Fertility treatment bears no excess breast cancer risk for BRCA1/2 mutation carriers

Among women carrying BRCA1/2 mutation, the use of fertility treatment does not contribute to a discernible increase in breast cancer risk, according to a study.

The analysis included a total of 1,824 Jewish Israeli women with confirmed BRCA1/2 mutation, among whom 332 (18.2 percent) had undergone fertility treatment with clomiphene citrate (n=134), gonadotropin (n=119), in vitro fertilization (n=183), or a combination of treatments (n=89). The remaining 1,492 (81.8 percent) women had not been treated for infertility.

Breast cancer was diagnosed in 687 women overall. Multivariable Cox proportional hazards analysis showed no link between fertility treatment and breast cancer risk in the overall population and when stratified by each gene.

The corresponding hazard ratios (HRs) for breast cancer were 0.77 (95 percent confidence interval [CI], 0.49–1.19) with clomiphene citrate, 0.54 (95 percent CI, 0.28–1.01) with gonadotropin, 0.65 (95 percent CI, 0.39–1.08) with in vitro fertilization, and 1.23 (95 percent CI, 0.49–3.06) with combined treatments.

Meanwhile, paternal origin of the mutation conferred a risk increase (HR, 1.43, 95 percent CI, 1.17–1.75), as did the long-term use of oral contraceptives (>5 years vs nonuse: HR, 1.62, 95 percent CI, 1.27–2.06), in both BRCA1 and BRCA2 mutation carriers.

Finally, women using any oral contraceptives were at lower risk of ovarian cancer (HR, 0.61, 95 percent CI, 0.46–0.82).