Oral contraceptives and the risk of breast cancer in BRCA1 and BRCA2 mutation carriers. Narod SA, Dube MP, Klijn J, et al. J Natl Cancer Inst 2002; 94(23): 1773-1779.

Contraceptive advice for the woman with a strong family history of breast and ovarian cancer is a difficult area. Some of these women carry known genetic mutations (BRCA1 and BRCA2) predisposing to breast and ovarian cancer. It remains unclear whether contraceptive steroids further increase their cancer risks. A recent international case-control study looked at the risks of breast cancer among 2622 women with these mutations. It was found that women with the BRCA1 gene mutation had a slightly higher risk of early-onset breast cancer if they had ever used oral contraception. The increased risk related particularly to women who had used oral contraception for more than 5 years, or at a younger age, or before 1975. Women with the BRCA2 gene mutation appeared not to increase their breast cancer risk by using oral contraception, however far fewer of these women were studied. This well-designed study adds to our knowledge in this difficult area but frustratingly did not look specifically at the oestrogen/progestogen content of oral contraceptives used by the women. Any evidence of increased breast cancer risk must be weighed against growing evidence that combined oral contraception helps protect against ovarian cancer in these high-risk women.