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.

The impact of reproductive life on breast cancer risk in women with family history or BRCA mutation.

Reproductive history and exogenous hormonal exposures are acknowledged risk factors for breast cancer in the general population. In women at increased breast cancer risk for genetic predisposition or positive family history, data regarding these risk factors are limited or conflicting, and recommendations for these categories are unclear. We evaluated the characteristics of reproductive life in 2522 women at increased genetic or familial breast cancer risk attending our Family Cancer Center. Breast cancers in BRCA mutation carriers were more likely to be hormone receptor negative, diagnosed at 35 years or before and multiple during the lifetime than tumors in women at increased familial risk, while the distribution of invasive cancers and HER2 positive tumors was similar in the different risk groups. At least one full-term pregnancy (HR 0.27; 95% CI 0.12-0.58; p = 0.001), breastfeeding either less (HR 0.24; 95% CI 0.09-0.66; p = 0.005) or more (HR 0.25; 95% IC 0.08-0.82; p = 0.022) than one year and late age at menopause (HR 0.10; 95% CI 0.01-0.82; p = 0.033) showed to be protective factors in BRCA mutation carriers, while in women at increased familial risk early age at first full-term pregnancy (HR 0.62; 95% IC 0.38-0.99; p = 0.048) and late menarche (HR 0.61; 95% CI 0.42-0.85; p = 0.004) showed to be the main protective factors. Finally, for the entire population, combined hormonal contraceptives demonstrated to do not increase breast cancer risk. The results of our study suggest that women at high familial risk and mutation carries develop tumors with different clinical-pathological characteristics and, consequently, are influenced by different protective and risk factors.