Hormonal Contraception Increases Breast Cancer Risk

December 28th, 2017

It is estimated that approximately 140 million women worldwide use hormonal contraception and this number accounts for approximately 13% of women between the ages of 15 and 49 years. Estrogen promotes the development of breast cancer and there is evidence to suggest that use of hormonal contraception at a young age may confer a higher risk of breast cancer than initiation of use later in life.
In a recent study (N Engl J Med 2017; 377:2228-2239), it was noted that the relative risk of breast cancer among all current and recent users of hormonal contraception was 1.20 (20% higher than average). This risk increased from 1.09 (9% higher than average) with less than 1 year of use to 1.38 (38% higher than average) with more than 10 years of hormonal contraception use (P=0.002). After discontinuation of hormonal contraception, the risk of breast cancer continued to be higher among the women who had used hormonal contraceptives for 5 years or more than among women who had not used hormonal contraceptives. Women who currently or recently used the progestin-only intrauterine system also had a higher risk of breast cancer than women who had never used hormonal contraceptives, with a relative risk of 1.21 (21% higher than average). These findings unequivocally suggest that no hormonal contraceptives are free of risk.