A case–control analysis of oral contraceptive use and breast cancer subtypes in the African American Breast Cancer Epidemiology and Risk Consortium

Abstract Introduction Recent oral contraceptive (OC) use has been consistently associated with increased risk of breast cancer, but evidence on specific breast cancer subtypes is sparse. Methods We investigated recency and duration of OC use in relation to molecular subtypes of breast cancer in a pooled analysis of data from the African American Breast Cancer Epidemiology and Risk Consortium. The study included 1,848 women with estrogen receptor-positive (ER+) breast cancer, 1,043 with ER-negative (ER-) breast cancer (including 494 triple negative (TN) tumors, which do not have receptors for estrogen, progesterone, and human epidermal growth factor 2), and 10,044 controls. Multivariable polytomous logistic regression models were used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for exposure categories relative to never use, controlling for potential confounding variables. Results OC use within the previous 5 years was associated with increased risk of ER+ (OR 1.46, 95% CI 1.18 to 1.81), ER- (OR 1.57, 95% CI 1.22 to 1.43), and TN (OR 1.78, 95% CI 1.25 to 2.53) breast cancer. The risk declined after cessation of use but was apparent for ER+ cancer for 15 to 19 years after cessation and for ER- breast cancer for an even longer interval after cessation. Long duration of use was also associated with increased risk of each subtype, particularly ER-. Conclusions Our results suggest that OC use, particularly recent use of long duration, is associated with an increased risk of ER+, ER-, and TN breast cancer in African American women. Research into mechanisms that explain these findings, especially the association with ER- breast cancer, is needed

Migraine and Use of Progestin-Only Contraception

Progestin-only contraception (POC) is not associated with an increased risk for cardiovascular events. In contrast to combined hormonal contraceptives, POC does not increase frequency of migraine attacks and does not initiate migraine. The continuous use of this contraceptive might contribute to the good tolerability in migraineurs. Only for the progestin-only pill with desogestrel 75 μg has it been demonstrated in several studies that it exerts significant reduction in migraine days and migraine intensity. This observation was made for migraine with and without aura. The LNG_IUS 20 is not well tolerated by many migraineurs, potentially as a result of highly fluctuating estrogen levels caused from ovarian cysts