Our knowledge of epidemiologic risk factors for
ovarian cancer supports a role for
androgens in the pathogenesis of this disease; however, few studies have examined associations between circulating
androgens and
ovarian cancer risk. Using highly sensitive LC-MS/MS assays, we evaluated associations between pre-diagnostic serum levels of 12
androgens, including novel
androgen metabolites that reflect
androgen activity in tissues, and
ovarian cancer risk among postmenopausal women in a nested case-control study in the Women's Health Initiative (WHI) Observational Study (OS). We frequency-matched 169
ovarian cancer cases to 410 controls from women enrolled in WHI-OS who were not using menopausal
hormones at enrollment/blood draw. We estimated associations overall and by subtype (n = 102 serous/67 non-serous) using multivariable adjusted logistic regression.
Androgen/
androgen metabolite levels were not associated with overall
ovarian cancer risk. In analyses by subtype, women with increased levels of
androsterone-glucuronide (ADT-G) and total 5-α reduced
glucuronide metabolites (markers of tissue-level androgenic activity) were at increased risk of developing non-serous
ovarian cancer: ADT-G tertile (T)3 versus T1 odds ratio [OR] (95% confidence interval [CI]) 4.36 (1.68-11.32), p-heterogeneity 0.002; total
glucuronide metabolites 3.63 (1.47-8.95), 0.002. Risk of developing serous
tumors was unrelated to these markers. ADT-G and total
glucuronide metabolites, better markers of tissue-level androgenic activity in women than
testosterone, were associated with an increased risk of developing non-serous
ovarian cancer. Our work demonstrates that sex
steroid metabolism is important in the etiology of non-serous
ovarian cancers and supports a heterogeneous hormonal etiology across histologic subtypes of
ovarian cancer.