Shelley S. Tworoger

Patterns of Associations with Epidemiologic Factors by High-Grade Serous Ovarian Cancer Gene Expression Subtypes

Abstract Background: Ovarian high-grade serous carcinomas (HGSC) comprise four distinct molecular subtypes based on mRNA expression patterns, with differential survival. Understanding risk factor associations is important to elucidate the etiology of HGSC. We investigated associations between different epidemiologic risk factors and HGSC molecular subtypes. Methods: We pooled data from 11 case–control studies with epidemiologic and tumor gene expression data from custom NanoString CodeSets developed through a collaboration within the Ovarian Tumor Tissue Analysis consortium. The PrOTYPE-validated NanoString-based 55-gene classifier was used to assign HGSC gene expression subtypes. We examined associations between epidemiologic factors and HGSC subtypes in 2,070 cases and 16,633 controls using multivariable-adjusted polytomous regression models. Results: Among the 2,070 HGSC cases, 556 (27%) were classified as C1.MES, 340 (16%) as C5.PRO, 538 (26%) as C2.IMM, and 636 (31%) as C4.DIF. The key factors, including oral contraceptive use, parity, breastfeeding, and family history of ovarian cancer, were similarly associated with all subtypes. Heterogeneity was observed for several factors. Former smoking [OR = 1.25; 95% confidence interval (CI) = 1.03, 1.51] and genital powder use (OR = 1.42; 95% CI = 1.08, 1.86) were uniquely associated with C2.IMM. History of endometriosis was associated with C5.PRO (OR = 1.46; 95% CI = 0.98, 2.16) and C4.DIF (OR = 1.27; 95% CI = 0.94, 1.71) only. Family history of breast cancer (OR = 1.44; 95% CI = 1.16, 1.78) and current smoking (OR = 1.40; 95% CI = 1.11, 1.76) were associated with C4.DIF only. Conclusions: This study observed heterogeneous associations of epidemiologic and modifiable factors with HGSC molecular subtypes. Impact: The different patterns of associations may provide key information about the etiology of the four subtypes.

Prospective Analysis of Circulating Biomarkers and Ovarian Cancer Risk in the UK Biobank

Abstract Background: Risk factors have a limited ability to predict individuals at high risk of developing ovarian cancer among average-risk women, highlighting the need for discovery of novel biomarkers. In the UK Biobank, we investigated serum biomarkers commonly measured in clinical laboratory tests and ovarian cancer risk. Methods: We conducted a prospective analysis of 20 serum biomarkers and ovarian cancer risk in 232,037 female UK Biobank participants (including 1,122 incident ovarian cancer cases diagnosed from 2006 to 2020). Multivariable adjusted Cox proportional hazards models were used to examine associations between biomarkers and ovarian cancer risk overall and by histotype. FDR was used to account for multiple testing. Results: Overall, higher levels of insulin-like growth factor (IGF)-1 [RRquartile 4 vs. 1 = 0.73; 95% confidence interval (CI), 0.60–0.87; P-trend = 0.002/FDR = 0.04], HbA1c (RRquartile 4 vs. 1 = 0.74; 95% CI, 0.62–0.89; P-trend = 0.002/FDR = 0.04), and alanine aminotransferase (RRquartile 4 vs. 1 = 0.76; 95% CI, 0.63–0.91; P-trend = 0.002/FDR = 0.04) were significantly associated with lower ovarian cancer risk. When stratified by histotype, higher IGF1 levels were associated with lower risk of serous (RRquartile 4 vs. 1 = 0.73; 95% CI, 0.58–0.91; P-trend = 0.01/FDR = 0.20) and clear cell tumors (RRquartile 4 vs. 1 = 0.18; 95% CI, 0.07–0.49; P-trend = 0.001/FDR = 0.02), and higher HbA1c levels were associated with lower risk of serous tumors (RRquartile 4 vs. 1 = 0.73; 95% CI, 0.59–0.90; P-trend = 0.004/FDR = 0.08). Conclusions: We observed that higher levels of circulating IGF1, HbA1c, and alanine aminotransferase were associated with lower ovarian cancer risk. Impact: These results suggest metabolism of glucose/amino acid and insulin/IGF1 signaling pathway may be contributing to ovarian carcinogenesis. Further research is needed to replicate our findings and elucidate how systemic changes in metabolism impact ovarian carcinogenesis.

Associations between common contraceptive use and circulating inflammatory biomarkers

Abstract Ovarian cancer incidence has declined in recent decades, due in part to oral contraceptive (OC) use and tubal ligation. However, intrauterine device (IUD) use has increasingly replaced OC use. As ovarian cancer is an inflammation-related disease, we examined the association of OC use, IUD use, and tubal ligation with plasma levels of C-reactive protein (CRP), interleukin 6, and soluble tumor necrosis factor α receptor 2 in the Nurses’ Health Study (NHS) and NHSII. After adjusting for reproductive, hormonal, and lifestyle factors and mutual adjustment for other methods of contraception, there were no differences in inflammatory markers between ever and never use of each method. However, CRP levels decreased from an average of 30.4% (95% CI, –53.6 to 4.4) with every 5 years since initial IUD use (P-trend = .03), while CRP increased an average of 9.9% (95% CI, 5.7, 14.3) with every 5 years of use of OC (P-trend < .0001) as well as differences by body mass index and menopausal status. Our results suggest IUD use and tubal ligation are not associated with higher circulating inflammatory markers long term, although long duration of OC use may increase generalized inflammation, which may in part explain why its protective effect wanes over time. This article is part of a Special Collection on Gynecological Cancer.

Lifetime Exposure to Cigarette Smoke, B-Cell Tumor Immune Infiltration, and Immunoglobulin Abundance in Ovarian Tumors

Abstract Background: Cigarette smoke exposure has been linked to systemic immune dysfunction, including for B-cell and immunoglobulin (Ig) production, and poor outcomes in patients with ovarian cancer. No study has evaluated the impact of smoke exposure across the life-course on B-cell infiltration and Ig abundance in ovarian tumors. Methods: We measured markers of B and plasma cells and Ig isotypes using multiplex immunofluorescence on 395 ovarian cancer tumors in the Nurses’ Health Study (NHS)/NHSII. We conducted beta-binomial analyses evaluating odds ratios (OR) and 95% confidence intervals (CI) for positivity of immune markers by cigarette exposure among cases and Cox proportional hazards models to evaluate hazard ratios (HR) and 95% CI for developing tumors with low (<median) or high (≥median) immune cell/Ig percentage. Results: There were no associations between smoke exposure and B-cell or IgM infiltration in ovarian tumors. Among cases, we observed higher odds of IgA+ among ever smokers (OR, 1.54; 95% CI, 1.14–2.07) and ever smokers with no parental smoke exposure (OR, 2.03; 95% CI, 1.18–3.49) versus never smokers. Women with parental cigarette smoke exposure versus not had higher risk of developing ovarian cancer with low IgG+ (HR, 1.51; 95% CI, 1.10–2.09), whereas ever versus never smokers had a lower risk (HR, 0.74; 95% CI, 0.56–0.99). Conclusions: Ever smoking was associated with increased odds of IgA in ovarian tumors. Impact: IgA has been associated with improved ovarian cancer outcomes, suggesting that although smoking is associated with poor outcomes in patients with ovarian cancer, it may lead to improved tumor immunogenicity.

Inequities in the Impacts of Hurricanes and Other Extreme Weather Events for Cancer Survivors

Abstract In this minireview, we examine the impacts of hurricanes and other extreme weather events on cancer survivors, focusing on structural and social determinants of health. We briefly explore influences on biological, psychosocial, and behavioral outcomes and discuss risk and resilience factors in cancer survivorship during and after hurricanes. Our goal is to inform future directions for research that can identify areas in which we can most efficiently improve cancer outcomes and inform changes in health systems, clinical practice, and public health policies. This timely minireview provides researchers and clinicians with an overview of challenges and opportunities for improving disaster preparedness and response for cancer survivors.

A Prospective Study Consortium for the Discovery and Validation of Early Detection Markers for Ovarian Cancer – Baseline Findings for CA125

Abstract Purpose: Epithelial ovarian cancer (EOC) is a lethal malignancy. Cancer antigen 125 (CA125), the “best” available marker for detecting EOC, has insufficient sensitivity and specificity for earlier-stage disease and is not a meaningful screening tool, motivating the search for further biomarkers. Cancer biomarker discovery is enhanced by “omics” technologies. Discovery studies for EOC biomarkers should be conducted in prediagnosis blood samples from prospective cohorts to maximize the likelihood of identifying markers that can detect disease before usual diagnosis and in earlier disease stage while reducing methodologic biases. Experimental Design: Individual cohorts with prediagnosis blood samples have insufficient sample size for such studies. Thus, we established “Prospective Early Detection Consortium for Ovarian Cancer” (“PREDICT”)—a collaboration of nine prospective studies—to assemble a sufficient number of EOC cases with blood samples collected ≤18 months before diagnosis plus controls. The 457 cases and 1,687 controls have circulating CA125 measured using a clinical assay. Results: The discrimination capacity for single CA125 measurements in samples collected <6 months prior to diagnosis was high (AUC; PREDICT overall = 0.92; range across cohorts of nonpregnant individuals = 0.89–0.98) and declined with extended time between blood collection and diagnosis. Between-cohort variability in CA125 levels and predictive performance was observed. Conclusions: Ongoing investigations in PREDICT are evaluating the early detection potential of tumor-associated autoantibodies and miRNAs using CA125 as a benchmark. PREDICT is a well-characterized resource for identifying and validating detection markers for EOC that may then be used in multimodal screening as a complement to CA125 and combined with imaging.

The relationship of lifetime history of depression on the ovarian tumor immune microenvironment

Depression is associated with a higher ovarian cancer risk. Prior work suggests that depression can lead to systemic immune suppression, which could potentially alter the anti-tumor immune response. We evaluated the association of pre-diagnosis depression with features of the anti-tumor immune response, including T and B cells and immunoglobulins, among women with ovarian tumor tissue collected in three studies, the Nurses' Health Study (NHS; n = 237), NHSII (n = 137) and New England Case-Control Study (NECC; n = 215). Women reporting depressive symptoms above a clinically relevant cut-point, antidepressant use, or physician diagnosis of depression at any time prior to diagnosis of ovarian cancer were considered to have pre-diagnosis depression. Multiplex immunofluorescence was performed on tumor tissue microarrays to measure immune cell infiltration. In pooled analyses, we estimated odds ratios (OR) and 95% confidence intervals (CI) for the positivity of tumor immune cells using a beta-binomial model comparing those with and without depression. We used Bonferroni corrections to adjust for multiple comparisons. We observed no statistically significant association between depression status and any immune markers at the Bonferroni corrected p-value of 0.0045; however, several immune markers were significant at a nominal p-value of 0.05. Specifically, there were increased odds of having recently activated cytotoxic (CD3 Our results provide suggestive evidence that depression may influence ovarian cancer outcomes through changes in the tumor immune microenvironment, including increasing T cell activation and exhaustion and reducing antibody-producing B cells. Further studies with clinical measures of depression and larger samples are needed to confirm these results.

The Association of Kidney Function and Inflammatory Biomarkers with Epithelial Ovarian Cancer Risk

Abstract Background: One of the mechanisms of ovarian tumorigenesis is through inflammation. Kidney dysfunction is associated with increased inflammation; thus, we assessed its relationship with ovarian cancer risk. Methods: In prospectively collected samples, we evaluated the association of kidney function markers and C-reactive protein (CRP) with ovarian cancer risk in the UK Biobank. We used multivariable-adjusted Cox proportional hazards models to evaluate quartiles of serum and urine markers with ovarian cancer risk overall and by histology. We assessed effect modification by CRP (≤3.0, >3.0 mg/L). Results: Among 232,908 women (1,110 ovarian cancer cases diagnosed from 2006–2020), we observed no association between estimated glomerular filtration rate and ovarian cancer risk (Q4 vs. Q1: HR, 1.00; 95% confidence intervals, 0.83–1.22). Potassium was associated with endometrioid (Q4 vs. Q1: 0.33, 0.11–0.98) and clear cell (4.74, 1.39–16.16) tumors. Poor kidney function was associated with a nonsignificant increase in ovarian cancer risk among women with CRP>3.0 mg/L (e.g., uric acid Q4 vs. Q1; 1.23, 0.81–1.86), but not CRP≤3.0 mg/L (0.83, 0.66–1.05). Other associations did not vary across CRP categories. Conclusions: Kidney function was not clearly associated with ovarian cancer risk. Larger studies are needed to evaluate possible histology specific associations. Given the suggestive trend for increased ovarian cancer risk in women with poor kidney function and high CRP, future work is needed, particularly in populations with a high prevalence of inflammatory conditions. Impact: This study provided the first evaluation of markers of kidney function in relation to ovarian cancer risk.

Associations between prediagnostic aspirin use and ovarian tumor gene expression

AbstractBackgroundAspirin use has been associated with reduced ovarian cancer risk, yet the underlying biological mechanisms are not fully understood. To gain mechanistic insights, we assessed the association between prediagnosis low and regular‐dose aspirin use and gene expression profiles in ovarian tumors.MethodsRNA sequencing was performed on high‐grade serous, poorly differentiated, and high‐grade endometrioid ovarian cancer tumors from the Nurses' Health Study (NHS), NHSII, and New England Case–Control Study (n = 92 cases for low, 153 cases for regular‐dose aspirin). Linear regression identified differentially expressed genes associated with aspirin use, adjusted for birth decade and cohort. False discovery rates (FDR) were used to account for multiple testing and gene set enrichment analysis was used to identify biological pathways.ResultsNo individual genes were significantly differentially expressed in ovarian tumors in low or regular‐dose aspirin users accounting for multiple comparisons. However, current versus never use of low‐dose aspirin was associated with upregulation of immune pathways (e.g., allograft rejection, FDR = 5.8 × 10−10; interferon‐gamma response, FDR = 2.0 × 10−4) and downregulation of estrogen response pathways (e.g., estrogen response late, FDR = 4.9 × 10−8). Ovarian tumors from current regular aspirin users versus never users were also associated with upregulation in interferon pathways (FDR <1.5 × 10−4) and downregulation of multiple extracellular matrix (ECM) architecture pathways (e.g., ECM organization, 4.7 × 10−8).ConclusionOur results suggest low and regular‐dose aspirin may impair ovarian tumorigenesis in part via enhancing adaptive immune response and decreasing metastatic potential supporting the likely differential effects on ovarian carcinogenesis and progression by dose of aspirin.

Germline Mutations in 12 Genes and Risk of Ovarian Cancer in Three Population-Based Cohorts

Abstract Background: With the widespread use of multigene panel genetic testing, population-based studies are necessary to accurately assess penetrance in unselected individuals. We evaluated the prevalence of germline pathogenic or likely pathogenic variants (mutations) in 12 cancer-predisposition genes and associations with ovarian cancer risk in three population-based prospective studies [Nurses’ Health Study (NHS), NHSII, Cancer Prevention Study II]. Methods: We included women with epithelial ovarian or peritoneal cancer (n = 776) and controls who were alive and had at least one intact ovary at the time of the matched case diagnosis (n = 1,509). Germline DNA was sequenced for mutations in 12 genes. Conditional logistic regression was used to estimate odds ratios (OR) and 95% confidence intervals (CI) for ovarian cancer risk by mutation status. Results: The mutation frequency across all 12 genes was 11.2% in cases and 3.3% in controls (P < 0.0001). BRCA1 and BRCA2 were the most frequently mutated (3.5% and 3.8% of cases and 0.3% and 0.5% of controls, respectively) and were associated with increased ovarian cancer risk [OR, BRCA1 = 12.38; 95% confidence interval (CI) = 4.72–32.45; OR, BRCA2 = 9.18; 95% CI = 3.98–21.15]. Mutation frequencies for the other genes were ≤1.0% and only PALB2 was significantly associated with risk (OR = 5.79; 95% CI = 1.09–30.83). There was no difference in survival for women with a BRCA germline mutation versus no mutation. Conclusions: Further research is needed to better understand the role of other mutations in ovarian cancer among unselected populations. Impact: Our data support guidelines for germline genetic testing for BRCA1 and BRCA2 among women diagnosed with epithelial ovarian cancer; testing for PALB2 may be warranted.

Multiple types of distress are prospectively associated with increased risk of ovarian cancer

AbstractBackgroundFew modifiable risk factors for epithelial ovarian cancer have been identified. We and other investigators have found that individual psychosocial factors related to distress are associated with higher risk of ovarian cancer. The present study examined whether co‐occurring distress‐related factors are associated with ovarian cancer risk.MethodsFive distress‐related factors were measured repeatedly over 21 years of follow‐up: depression, anxiety, social isolation, widowhood, and, in a subset or women, posttraumatic stress disorder (PTSD). Cox proportional hazards models estimate relative risks (RR) and 95% confidence intervals (CI) of ovarian cancer for a time‐updated count of distress‐related factors, in age‐adjusted models, then further adjusted for ovarian cancer risk factors and behavior‐related health risk factors.ResultsAcross 1,193,927 person‐years of follow‐up, 526 incident ovarian cancers occurred. Women with ≥3 versus no distress‐related psychosocial factors demonstrated increased ovarian cancer risk (HRage‐adjusted = 1.71; 95% CI = 1.16, 2.52). No significant difference in ovarian cancer risk was observed in women with one or two versus no distress‐related psychosocial factors. In the subsample with PTSD assessed, ≥3 versus no distress‐related psychosocial factors was associated with twofold greater ovarian cancer risk (HRage‐adjusted = 2.08, 95% CI = 1.01, 4.29). Further analysis suggested that women at highest ovarian cancer risk had PTSD co‐occurring with any other distress‐related factor (HR = 2.19, 95% CI = 1.20, 4.01). Adjusting for cancer risk factors and health behaviors minimally impacted risk estimates.ConclusionsPresence of multiple indicators of distress was associated with risk of ovarian cancer. When including PTSD as an indicator of distress, the association was strengthened.

Measurement of Ovarian Tumor Immune Profiles by Multiplex Immunohistochemistry: Implications for Epidemiologic Studies

Abstract Background: Despite the immunogenic nature of many ovarian tumors, treatment with immune checkpoint therapies has not led to substantial improvements in ovarian cancer survival. To advance population-level research on the ovarian tumor immune microenvironment, it is critical to understand methodologic issues related to measurement of immune cells on tissue microarrays (TMA) using multiplex immunofluorescence (mIF) assays. Methods: In two prospective cohorts, we collected formalin-fixed, paraffin-embedded ovarian tumors from 486 cases and created seven TMAs. We measured T cells, including several sub-populations, and immune checkpoint markers on the TMAs using two mIF panels. We used Spearman correlations, Fisher exact tests, and multivariable-adjusted beta-binomial models to evaluate factors related to immune cell measurements in TMA tumor cores. Results: Between-core correlations of intratumoral immune markers ranged from 0.52 to 0.72, with more common markers (e.g., CD3+, CD3+CD8+) having higher correlations. Correlations of immune cell markers between the whole core, tumor area, and stromal area were high (range 0.69–0.97). In multivariable-adjusted models, odds of T-cell positivity were lower in clear cell and mucinous versus type II tumors (ORs, 0.13–0.48) and, for several sub-populations, were lower in older tissue (sample age > 30 versus ≤ 10 years; OR, 0.11–0.32). Conclusions: Overall, high correlations between cores for immune markers measured via mIF support the use of TMAs in studying ovarian tumor immune infiltration, although very old samples may have reduced antigenicity. Impact: Future epidemiologic studies should evaluate differences in the tumor immune response by histotype and identify modifiable factors that may alter the tumor immune microenvironment.

Estrogen Receptor-β Expression of Ovarian Tumors and Its Association with Ovarian Cancer Risk Factors

Abstract Background: Differential associations between ovarian cancer risk factors and estrogen receptor-α (ERα) ovarian tumor expression have been noted; however, no research has assessed estrogen receptor-β (ERβ) expression. Thus, in exploratory analyses, we assessed the association of several factors with ovarian cancer risk by ERβ tumor status. Methods: We conducted a nested case–control study within the prospective Nurses' Health Study cohorts (NHS/NHSII), with exposures collected through biennial questionnaires. Paraffin-embedded tumor blocks were requested for cases diagnosed from 1976 to 2006 (NHS) and 1989 to 2005 (NHSII) and tissue microarrays were stained for nuclear ERβ (ERβ-nuc) and cytoplasmic ERβ (ERβ-cyto), with any staining considered positive (+). We obtained odds ratios (OR) and 95% confidence intervals (CI) using multivariate polytomous logistic regression. Results: We included 245 cases [43% ERβ-cyto (+) and 71% ERβ-nuc (+)] and 1,050 matched controls. An inverse association was observed between parity and risk of ERβ-nuc (+) (OR, parous vs. nulliparous: 0.46; 95% CI, 0.26–0.81), but not ERβ-nuc (–) tumors (OR, parous vs. nulliparous: 1.51; 95% CI, 0.45–5.04; Pheterogeneity = 0.04). Conversely, parity was inversely associated with ERβ-cyto (–) tumors (OR, parous vs. nulliparous: 0.42; 95% CI, 0.23–0.78), but was not associated with ERβ-cyto (+) tumors (OR, parous vs. nulliparous: 1.08; 95% CI, 0.45–2.63; Pheterogeneity = 0.05). Associations for other exposures, including hormone therapy, did not differ by ERβ-nuc or ERβ-cyto status. Conclusions: Our results suggest that parity may influence ovarian cancer risk, in part, through alterations in ERβ localization within tumor cells. Impact: Alterations in ERβ expression and localization appear to be important for ovarian cancer etiology. Future research should confirm our results and assess potential biologic mechanisms for the observed associations.

Ovarian Cancer Risk Factor Associations by Primary Anatomic Site: The Ovarian Cancer Cohort Consortium

Abstract Background: Epithelial ovarian, fallopian tube, and primary peritoneal cancers have shared developmental pathways. Few studies have prospectively examined heterogeneity in risk factor associations across these three anatomic sites. Methods: We identified 3,738 ovarian, 337 peritoneal, and 176 fallopian tube incident cancer cases in 891,731 women from 15 prospective cohorts in the Ovarian Cancer Cohort Consortium. Associations between 18 putative risk factors and risk of ovarian, peritoneal, and fallopian tube cancer, overall and for serous and high-grade serous tumors, were evaluated using competing risks Cox proportional hazards regression. Heterogeneity was assessed by likelihood ratio tests. Results: Most associations did not vary by tumor site (Phet ≥ 0.05). Associations between first pregnancy (Phet = 0.04), tubal ligation (Phet = 0.01), and early-adult (age 18–21 years) body mass index (BMI; Phet = 0.02) and risk differed between ovarian and peritoneal cancers. The association between early-adult BMI and risk further differed between peritoneal and fallopian tube cancer (Phet = 0.03). First pregnancy and tubal ligation were inversely associated with ovarian, but not peritoneal, cancer. Higher early-adult BMI was associated with higher risk of peritoneal, but not ovarian or fallopian tube, cancer. Patterns were generally similar when restricted to serous and high-grade serous cases. Conclusions: Ovarian, fallopian tube, and primary peritoneal cancers appear to have both shared and distinct etiologic pathways, although most risk factors appear to have similar associations by anatomic site. Impact: Further studies on the mechanisms underlying the differences in risk profiles may provide insights regarding the developmental origins of tumors arising in the peritoneal cavity and inform prevention efforts.

The Risk of Ovarian Cancer Increases with an Increase in the Lifetime Number of Ovulatory Cycles: An Analysis from the Ovarian Cancer Cohort Consortium (OC3)

Abstract Repeated exposure to the acute proinflammatory environment that follows ovulation at the ovarian surface and distal fallopian tube over a woman's reproductive years may increase ovarian cancer risk. To address this, analyses included individual-level data from 558,709 naturally menopausal women across 20 prospective cohorts, among whom 3,246 developed invasive epithelial ovarian cancer (2,045 serous, 319 endometrioid, 184 mucinous, 121 clear cell, 577 other/unknown). Cox models were used to estimate multivariable-adjusted HRs between lifetime ovulatory cycles (LOC) and its components and ovarian cancer risk overall and by histotype. Women in the 90th percentile of LOC (>514 cycles) were almost twice as likely to be diagnosed with ovarian cancer than women in the 10th percentile (<294) [HR (95% confidence interval): 1.92 (1.60–2.30)]. Risk increased 14% per 5-year increase in LOC (60 cycles) [(1.10–1.17)]; this association remained after adjustment for LOC components: number of pregnancies and oral contraceptive use [1.08 (1.04–1.12)]. The association varied by histotype, with increased risk of serous [1.13 (1.09–1.17)], endometrioid [1.20 (1.10–1.32)], and clear cell [1.37 (1.18–1.58)], but not mucinous [0.99 (0.88–1.10), P-heterogeneity = 0.01] tumors. Heterogeneity across histotypes was reduced [P-heterogeneity = 0.15] with adjustment for LOC components [1.08 serous, 1.11 endometrioid, 1.26 clear cell, 0.94 mucinous]. Although the 10-year absolute risk of ovarian cancer is small, it roughly doubles as the number of LOC rises from approximately 300 to 500. The consistency and linearity of effects strongly support the hypothesis that each ovulation leads to small increases in the risk of most ovarian cancers, a risk that cumulates through life, suggesting this as an important area for identifying intervention strategies. Significance: Although ovarian cancer is rare, risk of most ovarian cancers doubles as the number of lifetime ovulatory cycles increases from approximately 300 to 500. Thus, identifying an important area for cancer prevention research.

Reproductive and Hormonal Factors and Risk of Ovarian Cancer by Tumor Dominance: Results from the Ovarian Cancer Cohort Consortium (OC3)

Abstract Background: Laterality of epithelial ovarian tumors may reflect the underlying carcinogenic pathways and origins of tumor cells. Methods: We pooled data from 9 prospective studies participating in the Ovarian Cancer Cohort Consortium. Information on measures of tumor size or tumor dominance was extracted from surgical pathology reports or obtained through cancer registries. We defined dominant tumors as those restricted to one ovary or where the dimension of one ovary was at least twice as large as the other, and nondominant tumors as those with similar dimensions across the two ovaries or peritoneal tumors. Competing risks Cox models were used to examine whether associations with reproductive and hormonal risk factors differed by ovarian tumor dominance. Results: Of 1,058 ovarian cancer cases with tumor dominance information, 401 were left-dominant, 363 were right-dominant, and 294 were nondominant. Parity was more strongly inversely associated with risk of dominant than nondominant ovarian cancer (Pheterogeneity = 0.004). Ever use of oral contraceptives (OC) was associated with lower risk of dominant tumors, but was not associated with nondominant tumors (Pheterogeneity = 0.01). Higher body mass index was associated with higher risk of left-dominant tumors, but not significantly associated with risk of right-dominant or nondominant tumors (Pheterogeneity = 0.08). Conclusions: These data suggest that reproductive and hormonal risk factors appear to have a stronger impact on dominant tumors, which may have an ovarian or endometriosis origin. Impact: Examining the associations of ovarian cancer risk factors by tumor dominance may help elucidate the mechanisms through which these factors influence ovarian cancer risk.

Prediagnosis and postdiagnosis smoking and survival following diagnosis with ovarian cancer

Little is known about the influence of prediagnosis and postdiagnosis smoking and smoking cessation on ovarian cancer survival. We investigated this relationship in two prospective cohort studies, the Nurses’ Health Study (NHS) and NHSII. Analyses included 1,279 women with confirmed invasive, Stage I–III epithelial ovarian cancer. We used Cox proportional hazards regression models to estimate hazard ratios (HR) and 95% confidence intervals (CI) for ovarian cancer‐specific mortality by smoking status, adjusting for age and year of diagnosis, tumor stage, histologic subtype, body mass index and nonsteroidal anti‐inflammatory use (postdiagnosis models only). When examining prediagnosis smoking status (assessed a median of 12 months before diagnosis), risk of death was significantly increased for former smokers (HR = 1.19, 95% CI: 1.02–1.39), and suggestively for current smokers (HR = 1.21, 95% CI: 0.96–1.51) vs. never smokers. Longer smoking duration (≥20 years vs. never, HR = 1.23, 95% CI: 1.05–1.45) and higher pack‐years (≥20 pack‐years vs. never, HR = 1.28, 95% CI: 1.07–1.52) were also associated with worse outcome. With respect to postdiagnosis exposure, women who smoked ≥15 cigarettes per day after diagnosis (assessed a median of 11 months after diagnosis) had increased mortality compared to never smokers (HR = 2.34, 95% CI: 1.63–3.37). Those who continued smoking after diagnosis had 40% higher mortality (HR = 1.40, 95% CI: 1.05–1.87) compared to never smokers. Overall, our results suggest both prediagnosis and postdiagnosis smoking are associated with worse ovarian cancer outcomes.

Patterns and predictors of genetic referral among ovarian cancer patients at a National Cancer Institute‐Comprehensive Cancer Center

Abstract Germline mutations (eg, BRCA1 / 2 ) have prognostic and treatment implications for ovarian cancer (OVCA) patients. Thus, national guidelines recommend genetic testing for OVCA patients. The present study examines patterns and predictors of genetics referral in OVCA patients. Electronic medical record data were abstracted retrospectively from 557 OVCA patients treated from 1 January 2001 to 31 December 2015. Logistic regression models identified sociodemographic characteristics, disease/treatment characteristics, family history data, provider characteristics, and survival data that predicted genetics referral. Overall, 27.5% of patients received referral. Eleven variables predicting referral were selected during stepwise regression: younger age, White race, not having private insurance, professional school education, year of OVCA diagnosis, platinum sensitivity, female gynecologic oncologist, chemotherapy administered by a gynecologic oncologist, clinical trial enrollment, longer overall survival, and family history of OVCA. Genetics referral among OVCA patients was similar to rates reported nationwide. Unique predictive factors will contribute to quality improvement and should be validated at a multi‐institutional level to ensure guideline concordant care is provided to all OVCA patients. Future research should identify both patient‐level and provider‐level factors associated with genetics referral.

Adult dietary fat intake and ovarian cancer risk

The association of dietary fat intake with ovarian cancer risk has been inconsistent across populations. We examined dietary fat intake, overall and by type and ovarian cancer risk in two prospective cohort studies. We assessed long‐term dietary fat intake among Nurses’ Health Study (NHS) and NHSII participants using food frequency questionnaires administered every 2–4 years beginning in 1984 and 1991, respectively. We examined cumulative energy‐adjusted intake of total fat, specific types of fat (animal, vegetable, saturated, monounsaturated, polyunsaturated and trans fat) and cholesterol. We identified 700 ovarian cancer cases in NHS and 196 in NHSII with dietary information. Cox proportional hazards regression was used to estimate associations between intake and ovarian cancer risk. Dietary fat intake changed over time in both cohorts and was lower in NHS than NHSII. Higher cumulative average intakes of animal fat and cholesterol were significantly positively associated with risk of ovarian cancer in NHS (relative risk [RR] comparing extreme quartiles = 1.57, 95% CI: 1.20, 2.06 and 1.35, 95% CI: 1.08, 1.69, respectively), but not in NHSII. Other dietary fat sources were not clearly associated with risk in either population. We did not observe clear associations between dietary fat and ovarian cancer risk in two large prospective cohort studies.

Ovarian Cancer Risk in Relation to Blood Cholesterol and Triglycerides

Abstract Background: The association between circulating cholesterol and triglyceride levels and ovarian cancer risk remains unclear. Methods: We prospectively evaluated the association between cholesterol [total, low-density lipoprotein (LDL-C), and high-density lipoprotein (HDL-C)] and triglycerides and ovarian cancer incidence in a case–control study nested in the Nurses' Health Study (NHS) and NHSII cohorts and a longitudinal analysis in the UK Biobank. Results: A total of 290 epithelial ovarian cancer cases in the NHS/NHSII and 551 cases in UK Biobank were diagnosed after blood collection. We observed a reduced ovarian cancer risk comparing the top to bottom quartile of total cholesterol [meta-analysis relative risk (95% confidence interval): 0.81 (0.65–1.01), Ptrend 0.06], with no heterogeneity across studies (Pheterogeneity = 0.74). Overall, no clear patterns were observed for HDL-C, LDL-C, or triglycerides and ovarian cancer risk. Comparing triglyceride levels at clinically relevant cut-off points (>200 vs. ≤200 mg/dL) for cases diagnosed more than 2 years after blood draw saw a positive relationship with risk [1.57 (1.03–2.42); Pheterogeneity = 0.003]. Results were similar by serous/non-serous histotype, menopausal status/hormone use, and body mass index. Conclusions: Data from two large cohorts in the United States and United Kingdom suggest that total cholesterol levels may be inversely associated with ovarian cancer risk, while triglycerides may be positively associated with risk when assessed at least 2 years before diagnosis, albeit both associations were modest. Impact: This analysis of two large prospective studies suggests that circulating lipid levels are not strongly associated with ovarian cancer risk. The positive triglyceride–ovarian cancer association warrants further evaluation.

Early life physical activity and risk of ovarian cancer in adulthood

AbstractEmerging data suggest that exposures in early life may affect ovarian development and contribute to ovarian cancer risk. We evaluated the association between early life physical activity and risk of ovarian cancer in adulthood in two large prospective cohorts, the Nurses' Health Study (NHS) and NHSII. In total, analyses included 28 232 NHS participants (followed from 2004 to 2016) and 56 553 NHSII participants (followed from 1997 to 2017). Cox proportional hazards models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for risk of ovarian cancer overall and by early life body mass index (BMI). Neither physical activity at ages 12‐13, 14‐17 or 18‐22 years nor average physical activity across these three periods was associated with ovarian cancer risk overall (≥78 vs <24 MET‐h/wk, HRs = 1.34, 1.21, 1.08 and 1.24, respectively), or by categories of early life BMI (Pheterogeneity ≥ .44). No association was observed with the risk of high‐grade serous or poorly differentiated tumors or postmenopausal ovarian cancer. Overall, early life physical activity was not clearly related to ovarian cancer risk during adulthood.

Common Analgesic Use for Menstrual Pain and Ovarian Cancer Risk

Abstract Menstrual pain has been associated with increased ovarian cancer risk, presumably through increased inflammation, which is known to play a critical role in ovarian carcinogenesis. Analgesic medications are frequently used to treat menstrual pain, some of which lower ovarian cancer risk. In this study, we examined the association between analgesic use for menstrual pain during the premenopausal period and ovarian cancer risk among women with history of menstrual pain. We used data from the New England Case-Control Study, including 1,187 epithelial ovarian cancer cases and 1,225 population-based controls enrolled between 1998 and 2008 with detailed information on analgesic use for their menstrual pain. We used unconditional logistic regression to calculate the odds ratios (ORs) and 95% confidence intervals (CIs) for the association between analgesic use (i.e., aspirin, ibuprofen, acetaminophen) for menstrual pain and ovarian cancer risk. We further conducted a stratified analysis by intensity of menstrual pain (mild/moderate, severe). Among women with menstrual pain during their 20s and 30s, ever use of analgesics for menstrual pain was not significantly associated with ovarian cancer risk. However, among women with severe menstrual pain, ever use of aspirin or acetaminophen for menstrual pain was inversely associated with risk (OR, 0.41; 95% CI, 0.18–0.94 and OR, 0.43; 95% CI, 0.21–0.88 compared with never users, respectively). No significant association was observed between analgesic use and ovarian cancer risk among women with mild/moderate menstrual pain (Pinteraction ≤ 0.03). Our results suggest that use of aspirin or acetaminophen for severe menstrual pain may be associated with lower risk of ovarian cancer. Prevention Relevance: This study investigates whether analgesic use specifically for menstrual pain during the premenopausal period influences ovarian cancer risk. Our results suggest use of aspirin or acetaminophen for severe menstrual pain may be associated with lower risk of ovarian cancer among women with severe menstrual pain.

Prolactin and Risk of Epithelial Ovarian Cancer

Abstract Background: Prolactin is synthesized in the ovaries and may play a role in ovarian cancer etiology. One prior prospective study observed a suggestive positive association between prolactin levels and risk of ovarian cancer. Methods: We conducted a pooled case–control study of 703 cases and 864 matched controls nested within five prospective cohorts. We used unconditional logistic regression to calculate adjusted odds ratios (OR) and 95% confidence intervals (CI) for the association between prolactin and ovarian cancer risk. We examined heterogeneity by menopausal status at blood collection, body mass index (BMI), age, and histotype. Results: Among women with known menopausal status, we observed a positive trend in the association between prolactin and ovarian cancer risk (Ptrend = 0.045; OR, quartile 4 vs. 1 = 1.34; 95% CI = 0.97–1.85), but no significant association was observed for premenopausal or postmenopausal women individually (corresponding OR = 1.38; 95% CI = 0.74–2.58; Ptrend = 0.32 and OR = 1.41; 95% CI = 0.93–2.13; Ptrend = 0.08, respectively; Pheterogeneity = 0.91). In stratified analyses, we observed a positive association between prolactin and risk for women with BMI ≥ 25 kg/m2, but not BMI < 25 kg/m2 (corresponding OR = 2.68; 95% CI = 1.56–4.59; Ptrend < 0.01 and OR = 0.90; 95% CI = 0.58–1.40; Ptrend = 0.98, respectively; Pheterogeneity < 0.01). Associations did not vary by age, postmenopausal hormone therapy use, histotype, or time between blood draw and diagnosis. Conclusions: We found a trend between higher prolactin levels and increased ovarian cancer risk, especially among women with a BMI ≥ 25 kg/m2. Impact: This work supports a previous study linking higher prolactin with ovarian carcinogenesis in a high adiposity setting. Future work is needed to understand the mechanism underlying this association.

Joint IARC/NCI International Cancer Seminar Series Report: expert consensus on future directions for ovarian carcinoma research

Abstract Recently, ovarian cancer research has evolved considerably because of the emerging recognition that rather than a single disease, ovarian carcinomas comprise several different histotypes that vary by etiologic origin, risk factors, molecular profiles, therapeutic approaches and clinical outcome. Despite significant progress in our understanding of the etiologic heterogeneity of ovarian cancer, as well as important clinical advances, it remains the eighth most frequently diagnosed cancer in women worldwide and the most fatal gynecologic cancer. The International Agency for Research on Cancer and the United States National Cancer Institute jointly convened an expert panel on ovarian carcinoma to develop consensus research priorities based on evolving scientific discoveries. Expertise ranged from etiology, prevention, early detection, pathology, model systems, molecular characterization and treatment/clinical management. This report summarizes the current state of knowledge and highlights expert consensus on future directions to continue advancing etiologic, epidemiologic and prognostic research on ovarian carcinoma.

Prediagnosis and postdiagnosis leisure time physical activity and survival following diagnosis with ovarian cancer

AbstractLittle is known about the influence of prediagnosis and postdiagnosis physical activity on ovarian cancer survival. We investigated this association in two large cohorts, the Nurses' Health Study (NHS) and NHSII. Analyses included 1461 women with confirmed invasive, epithelial ovarian cancer and data on physical activity. Cox regression models were used to estimate hazard ratios (HR) and 95% confidence intervals (CI) for ovarian cancer‐specific mortality. Ovarian cancer‐specific mortality was not associated with physical activity reported 1‐8 years before diagnosis overall (≥7.5 vs <1.5 MET‐hours/week, HR = 0.96), for high‐grade serous/ poorly differentiated tumors, or non‐serous/ low‐grade serous tumors (P‐heterogeneity = .45). An inverse association was observed for activity 1‐4 years after diagnosis (≥7.5 vs <1.5 MET‐hours/week, HR = 0.67, 95%CI: 0.48‐0.94), with similar results by histotype (P‐heterogeneity = .53). Women who decreased their activity from ≥7.5 MET‐hours/week 1‐8 years before diagnosis to <7.5 MET‐hours/week 1‐4 years after diagnosis, compared to those with <7.5 MET‐hours/week across periods, had a 49% increased risk of death (HR = 1.49, 95%CI: 1.07‐2.08). Physical activity after, but not before, ovarian cancer diagnosis was associated with better prognosis.

The association of resistance training with risk of ovarian cancer

ABSTRACTBackgroundIncreasing evidence, including multiple putative inflammatory risk factors (e.g., c‐reactive protein, and adiposity), supports that inflammation plays an important role in ovarian carcinogenesis. Resistance training (RT) is associated with lower levels of circulating inflammatory markers, independent of physical activity.MethodsWe evaluated the relationship between RT and risk of ovarian cancer accounting for other physical activity (e.g., walking) in two large prospective cohorts, the Nurses’ Health Study (NHS) and NHSII.Key ResultsIn total, analyses included 42,005 NHS participants (2000–2016) and 67,289 NHSII participants (2001–2017) with RT assessed every 4 years. Multivariable Cox proportional hazards models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) of RT with ovarian cancer risk overall and by tumor subtype, adjusting for known and putative ovarian cancer risk factors. We identified a total of 609 cases over 1,748,884 person‐years. No association was observed with overall ovarian cancer risk (RT ≥60 vs 0 min/wk, HR = 0.95, 95%CI: 0.74–1.22) or by histotype (comparable HR = 0.86 and 0.98 for type I and II tumors, respectively). Results did not differ by body mass index (Pinteraction = 0.97), or other physical activity (Pinteraction = 0.31).Conclusions & InferencesWe observed no evidence that moderate levels of RT were associated with risk of ovarian cancer. Further investigations are required to confirm these findings.

Prospective Analyses of Lifestyle Factors Related to Energy Balance and Ovarian Cancer Risk by Infiltration of Tumor-Associated Macrophages

Abstract Background: Lifestyle factors related to energy balance have been associated with ovarian cancer risk and influence the tumor immune microenvironment, including tumor-associated macrophages (TAM). However, no studies have assessed whether these factors differentially impact ovarian cancer risk by TAM densities. Methods: We conducted a prospective analysis in the Nurses' Health Studies to examine the associations of physical activity, sitting time, and a food-based empirical dietary inflammatory pattern (EDIP) score with invasive epithelial ovarian cancer risk by TAM density assessed by immunohistochemistry. We considered density of CD68 (marker of total TAMs) and CD163 (marker of pro-carcinogenic M2-type TAMs), and their ratios. We used multivariable Cox proportional hazards regression to calculate hazard ratios (HR) and 95% confidence intervals (CI) of exposures with risk of ovarian tumors with high versus low TAMs, including analyses stratified by body mass index. Results: Analyses included 312 incident ovarian cancer cases with TAM measurements. Physical activity, sitting time, and EDIP score were not differentially associated with ovarian cancer risk by TAM densities (Pheterogeneity > 0.05). Among overweight and obese women, higher EDIP score was associated with increased risk of CD163 low-density tumors (HR comparing extreme tertiles, 1.57; 95% CI, 0.88–2.80; Ptrend = 0.01), but not CD163 high-density tumors (comparable HR, 1.16; 95% CI, 0.73–1.86; Ptrend = 0.24), though this difference was not statistically significant (Pheterogeneity = 0.22). Conclusions: We did not observe differential associations between lifestyle factors and ovarian cancer risk by TAM densities. Impact: Future investigations examining the interplay between other ovarian cancer risk factors and the tumor immune microenvironment may help provide insight into ovarian cancer etiology.

Circulating Biomarkers of Inflammation and Ovarian Cancer Risk in the Nurses' Health Studies

AbstractBackground:Chronic inflammation is a well-established mechanism of ovarian carcinogenesis; however, the specific immunogenic processes influencing ovarian tumor development remain unclear. In a case–control study nested within the Nurses' Health Study (NHS) and the NHSII, we examined the association between six inflammatory chemokines and cytokines [B-cell activating factor (BAFF), C-X-C motif chemokine ligand 13 (CXCL13), IL8, soluble(s)IL2-receptor-α(Rα), sIL6Rα] and epithelial ovarian cancer risk.Methods:Among 299 epithelial ovarian cancer cases and 334 matched controls, six inflammatory biomarkers were measured in plasma collected 1–24 years before diagnosis or index date using two custom multiplex Luminex panels. ORs and 95% confidence intervals (CI) were estimated for the association between each biomarker and risk using multivariable conditional logistic regression with adjustment for relevant confounders. We additionally assessed heterogeneity in the risk associations by histotype [high-grade serous carcinoma (HGSC) vs. non-HGSC], body mass index, smoking status, menopausal status, and aspirin use.Results:Women with the highest versus lowest quartile (Q) levels of CXCL13 had a 72% increased ovarian cancer risk (OR = 1.72; 95% CI = 1.04–2.83; Ptrend = 0.007). The positive association with CXCL13 was stronger in magnitude for non-HGSC, overweight or obese women, and postmenopausal women, although only menopausal status demonstrated statistically significant heterogeneity (Pinteraction = 0.04). The remaining biomarkers were not associated with risk.Conclusions:This first evidence that prediagnostic CXCL13, a B-cell chemoattractant, is associated with an increased risk of epithelial ovarian cancer expands current understanding of the role of inflammation in ovarian carcinogenesis.Impact:CXCL13 may represent a novel biomarker for ovarian cancer.

Modification of the Association Between Frequent Aspirin Use and Ovarian Cancer Risk: A Meta-Analysis Using Individual-Level Data From Two Ovarian Cancer Consortia

PURPOSE Frequent aspirin use has been associated with reduced ovarian cancer risk, but no study has comprehensively assessed for effect modification. We leveraged harmonized, individual-level data from 17 studies to examine the association between frequent aspirin use and ovarian cancer risk, overall and across subgroups of women with other ovarian cancer risk factors. METHODS Nine cohort studies from the Ovarian Cancer Cohort Consortium (n = 2,600 cases) and eight case-control studies from the Ovarian Cancer Association Consortium (n = 5,726 cases) were included. We used Cox regression and logistic regression to assess study-specific associations between frequent aspirin use (≥ 6 days/week) and ovarian cancer risk and combined study-specific estimates using random-effects meta-analysis. We conducted analyses within subgroups defined by individual ovarian cancer risk factors (endometriosis, obesity, family history of breast/ovarian cancer, nulliparity, oral contraceptive use, and tubal ligation) and by number of risk factors (0, 1, and ≥ 2). RESULTS Overall, frequent aspirin use was associated with a 13% reduction in ovarian cancer risk (95% CI, 6 to 20), with no significant heterogeneity by study design ( P = .48) or histotype ( P = .60). Although no association was observed among women with endometriosis, consistent risk reductions were observed among all other subgroups defined by ovarian cancer risk factors (relative risks ranging from 0.79 to 0.93, all P-heterogeneity > .05), including women with ≥ 2 risk factors (relative risk, 0.81; 95% CI, 0.73 to 0.90). CONCLUSION This study, the largest to-date on aspirin use and ovarian cancer, provides evidence that frequent aspirin use is associated with lower ovarian cancer risk regardless of the presence of most other ovarian cancer risk factors. Risk reductions were also observed among women with multiple risk factors, providing proof of principle that chemoprevention programs with frequent aspirin use could target higher-risk subgroups.

Tobacco Smoking and Survival Following a Diagnosis with Ovarian Cancer

Abstract Background: Little is known about the influence of smoking on ovarian cancer survival. We investigated this relationship in a hospital-based study. Methods: Analyses included 519 women with ovarian cancer. We used multivariable adjusted Cox proportional hazards regression models to estimate HRs and 95% confidence intervals (CI). Results: Risk of all-cause mortality was increased for current smokers (HR = 1.70; 95% CI: 1.09–2.63) versus never smokers, especially for those with ≥15 cigarettes per day (HR = 1.92; 95% CI: 1.15–3.20). Results were largely similar after additional adjustment for debulking status (current vs. never smokers, HR = 2.96; 95% CI: 1.07–8.21) or neoadjuvant chemotherapy (comparable HR = 2.87; 95% CI: 1.02–8.06). Compared with never smokers, smoking duration ≥20 years (HR = 1.38; 95% CI: 0.94–2.03) and ≥20 pack-years (HR = 1.35; 95% CI: 0.92–1.99) were suggestively associated with worse outcomes. Current smoking was also positively associated with the risk of mortality among patients with ovarian cancer recurrence (current vs. never/past smokers, HR = 2.79; 95% CI: 1.44–5.41), despite the null association between smoking and recurrence (HR = 1.46; 95% CI: 0.86–2.48). Furthermore, no association was observed for smoking initiation before age 18 (HR = 1.22; 95% CI: 0.80–1.85), or either environmental smoke exposure at home (HR = 1.16; 95% CI: 0.76–1.78) or at work (HR = 1.10; 95% CI: 0.75–1.60). Conclusions: Our results suggest active tobacco smoking is associated with worse ovarian cancer outcomes, particularly after a recurrence. Impact: Our findings support structured smoking cessation programs for patients with ovarian cancer, especially in recurrent settings. Further research to confirm these findings and examine the interplay between smoking and the tumor immune microenvironment may help provide insight into ovarian cancer etiology.

Cohort Profile: The Ovarian Cancer Cohort Consortium (OC3)

Associations between Parity, History of Breastfeeding, and T-cell Profile of Ovarian Tumors

Abstract Background: Parity and breastfeeding are associated with systemic changes in maternal inflammation and reduced risk of ovarian cancer, but little is known about their impact on the ovarian tumor immune microenvironment. Methods: We evaluated the associations of self-reported parity and history of breastfeeding with tumor-infiltrating T cells among 1,706 ovarian carcinoma cases with tumor tissue collected across four studies. The abundance of tumor-infiltrating T cells was measured by multiplex immunofluorescence in tumor tissue microarrays. ORs and 95% confidence intervals (CI) for the positivity of tumor immune cells were calculated using beta-binomial models and stratified by histotype. Results: Compared with ovarian tumors in nulliparous women, there was no association between parity and ovarian tumor T-cell abundance among all histotypes combined but suggestion of increased cytotoxic T cells and T-cell exhaustion among parous women with clear-cell tumors. When restricted to parous women, history of breastfeeding was associated with increased odds for all T-cell types [i.e., total T, cytotoxic T, helper T (Th), regulatory T, and exhausted T cells], with ORs ranging from 1.11 to 1.42. For every 6 months of breastfeeding, we observed increased odds of activated Th-cell infiltration (CD3+CD4+CD69+; OR, 1.13, 95% CI, 0.99–1.29), with a similar association for high-grade serous tumors, but lower odds in clear-cell tumors (OR, 0.43, 95% CI, 0.21–0.87). Conclusions: History of breastfeeding may alter the ovarian tumor immune microenvironment by modulating the abundance of tumor-infiltrating T cells. Impact: Although replication is required, history of breastfeeding may play a role in the activation of the ovarian tumor immune response.

Timing of depression in relation to risk of ovarian cancer

Abstract Background Several studies have suggested that depression may be associated with increased risk of ovarian cancer. Less is known about whether timing matters regarding when depression occurs. To provide evidence for an etiologically relevant exposure period, we examined depression occurring during the time in which precursor lesions develop and progress to invasive carcinoma with the risk of developing ovarian cancer. Methods Using data from 2 prospective cohorts (1992-2015), we divided follow-up into consecutive 2-year periods for analytic purposes, referred to as “cancer ascertainment periods.” We estimated associations of depression in the 10 years before each cancer ascertainment period with incident cancer, using Cox proportional hazards models. Next, we estimated associations of depression occurring up to 18 years before each ascertainment period, in 2-year increments, with incident cancer. We adjusted for demographic, health, and behavioral factors. All tests of statistical significance were two-sided, with a P-value threshold of less than .05. Results Depression occurring in the 10 prior years was associated with 30% greater risk of cancer (hazard ratio [HR] = 1.30, 95% confidence interval = 1.15 to 1.46). Associations were similar in fully adjusted models (HR = 1.27). Depression occurring in the 14 years before ascertainment was associated with elevated risk, although only estimates for depression 0-2, 6-8, and 8-10 years before ascertainment reached statistical significance (HR range = 1.20-1.36). Conclusion Depression occurring up to 14 years before cancer ascertainment was associated with greater cancer risk. This is the time of precursor progression to invasive ovarian carcinoma, suggesting depression may be an ovarian cancer-promoting agent.

Caregiver burden and risk of epithelial ovarian cancer in the Nurses’ Health Studies

Abstract Psychosocial stress may increase ovarian cancer risk and accelerate disease progression. We examined the association between caregiver burden, a common stressor, and risk of epithelial ovarian cancer. We prospectively followed 67 724 women in the Nurses’ Health Study (1992-2012) and 70 720 women in the Nurses’ Health Study II (2001-2009) who answered questions on informal caregiving (ie, caregiving outside of work). Women who reported no informal caregiving were considered noncaregivers, while, among women who provided care outside of work, caregiver burden was categorized by time spent caregiving and perceived stress from caregiving. For the 34% of women who provided informal care for ≥15 hours per week, 42% described caregiving as moderately to extremely stressful. Pooled multivariate analyses indicated no difference in ovarian cancer risk for women providing ≥15 hours of care per week compared to noncaregivers (hazard ratio [HR] = 0.96; 95% confidence interval [CI], 0.79-1.18), and no association was evident for women who reported moderate or extreme stress from caregiving compared to noncaregivers (HR = 0.96; 95% CI, 0.75-1.22). Together with prior work evaluating job strain and ovarian cancer risk, our findings suggest that, when evaluating a stressor’s role in cancer risk, it is critical to consider how the stressor contributes to the overall experience of distress. This article is part of a Special Collection on Gynecological Cancer.