Neal D Freedman

Associations of self-identified race and ethnicity and genetic ancestry with mortality among cancer survivors

Abstract Self-identified race and ethnicity (SIRE) and genetic ancestry are potentially associated with disparities in health outcomes; however, independent effects of SIRE and genetic ancestry on mortality in cancer survivors including when adjusting for multiple risk factors are understudied. Among 23 445 cancer survivors in the Prostate, Lung, Colorectal, and Ovarian Screening Trial, SIRE was associated with mortality among prostate, colorectal, lung, ovarian, and breast cancer survivors; genetic ancestry was associated with mortality among prostate, colorectal, and breast cancer survivors. Associations were strong when adjusting for age at cancer diagnosis, sex, and tumor characteristics but attenuated when adjusting for individual-level factors and population-level socioeconomic status. For example, mortality risk was higher among Black vs White prostate cancer survivors and African genetic ancestry vs European genetic ancestry, but associations were attenuated after multilevel adjustment. Results suggest that SIRE and genetic ancestry do not solely reflect biologic variation; rather, social factors may drive mortality differences by SIRE and genetic ancestry.

Serum perfluorooctane sulfonate and perfluorooctanoate and risk of postmenopausal breast cancer according to hormone receptor status: An analysis in the Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial

Abstract Per‐ and polyfluoroalkyl substances (PFAS) are highly persistent endocrine‐disrupting chemicals that may contribute to breast cancer development; however, epidemiologic evidence is limited. We investigated associations between prediagnostic serum levels of perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA) and postmenopausal breast cancer risk, overall and by hormone receptor status, in a nested case‐control study of 621 cases and 621 matched controls in the Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial. PFOS and PFOA levels were determined based on serum metabolomic profiling performed using ultraperformance liquid chromatography‐tandem mass spectrometry. We used multivariable conditional logistic regression to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for the association between each PFAS and breast cancer risk, overall, by estrogen receptor (ER) or progesterone receptor (PR) status, and by joint ER/PR status. We found little evidence of association between PFOS or PFOA and breast cancer risk overall. However, in subtype‐specific analyses, we observed statistically significant increased risks of ER+, PR+, and ER+/PR+ tumors for the third vs lowest quartile of serum PFOS (ORs [95% CIs] = 1.59 [1.01‐2.50], 2.34 [1.29‐4.23], and 2.19 [1.21‐3.98], respectively) and elevated but nonstatistically significant ORs for the fourth quartile. Conversely, for PFOA, modest positive associations with ER−, PR−, ER+/PR−, and ER−/PR− tumors were generally seen in the upper quartiles. Our findings contribute evidence supporting positive associations between serum PFOS and hormone receptor‐positive tumors, and possibly between PFOA and receptor‐negative tumors. Future prospective studies incorporating tumor hormone receptor status are needed to better understand the role of PFAS in breast cancer etiology.