Combined Hormonal Contraceptive Use and Risk of Breast Cancer in a Population of Women With a Family History

CHCs are the most used methods of contraception in the more developed world. Their use does not increase the risk of breast cancer in women with a family history of BC from our Family Cancer Clinic. These results are confirmed for very-high-risk (BRCA1-2), high-risk and intermediate-risk groups. Background: We estimated the association between combined hormonal contraceptive (CHC) use and breast cancer (BC) incidence in a well-selected population of women at familial risk of BC at the Modena Family Cancer Clinic. Materials and Methods: We performed a retrospective cohort study by reviewing the data from 2527 women (4.5% BRCA mutation carriers, 72.2% high risk, and 23.3% intermediate risk using the Modena criteria and the Tyrer-Cuzick model). Results: We did not find any specific feature of breast cancer (infiltration, hormone receptor and HER2 status, onset before age 35 years, multiple diagnoses) in the CHC users (P > .05). Only 2.0% of women used a preparation with 50 mg of ethinylestradiol (EE). The use of CHCs was not associated with an increased risk of breast cancer (cumulative hazard: never used, 0.17; CHC users, 0.20; P ¼ .998), regardless of the duration of use (cumulative hazard: never used, 0.17, used < 5 years, 0.20; used 5-10 years, 0.14; used > 10 years, 0.25; P ¼ .414). This was confirmed for the different risk groups when interacted in a Cox proportional hazard regression model. The EE dose did not influence the risk of BC (cumulative hazard, 2.37; 95% confidence interval, 0.53-10.1; never used, 0.18; EE < 20 mg used, 0.04; EE 20 mg used, 0.16; P ¼ .259). The types of progestins used might influence the risk, with some, such as gestodene (P ¼ .028) and cyproterone acetate (P ¼ .031), associated with an even greater reduced risk. Conclusions: CHC use does not increase the risk of BC in a population of women with a family history, encouraging CHC use in this group of women.