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

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 μg 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 = .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 = .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 μg used, 0.04; EE ≥ 20 μg used, 0.16; P = .259). The types of progestins used might influence the risk, with some, such as gestodene (P = .028) and cyproterone acetate (P = .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.