Kensler KH, et al. - Researchers determined the prognostic significance of circulating sex hormone levels, especially its association with survival, among 2,073 patients with breast cancer from the Nurses’ Health Study (NHS) and Nurses’ Health Study II (NHSII) cohorts in this study. Plasma samples from the patients were analyzed to measure levels of estradiol (postmenopausal women only), testosterone, dehydroepiandrosterone-sulfate (DHEAS), and sex hormone-binding globulin (SHBG). Adjusting for patient and tumor characteristics, hazard ratios and 95% confidence intervals for survival were calculated using Cox proportional hazards models. Over follow-up through 2015, the occurrence of 639 deaths and 160 breast cancer deaths were documented. The investigators noted a modest association of prediagnostic postmenopausal circulating estradiol levels with worse survival among breast cancer patients. A 1.43-fold overall mortality rate and a non-significantly higher breast cancer mortality rate were reported in postmenopausal women in the highest quartile of estradiol vs women in the lowest quartile. Also, a nonsignificant relation of higher DHEAS levels to better overall survival, though not to breast cancer survival, was observed. They did not observe any links between testosterone or SHBG and survival.