Alan A. Arslan

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.

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.