Women using hormonal contraceptives have 20 per cent higher risk of developing breast cancer, researchers at University of Copenhagen have found. The study, according to cancer specialists, reaffirms a long-held suspicion regarding contraceptive pills.
The researchers at the University of Copenhagen assessed associations between the use of hormonal contraception and the risk of invasive breast cancer in a nationwide prospective cohort study involving all women in Denmark between the age of 15 and 49 who had not had cancer or venous thromboembolism (a travelling blood clot that gets caught in a small-diameter vein) and who had not received treatment for infertility.
“The risk of breast cancer was higher among women who currently or recently used contemporary hormonal contraceptives than among women who had never used hormonal contraceptives, and this risk increased with longer durations of use; however, absolute increases in risk were small,” they concluded in an article in the New England Journal of Medicine. The study was funded by the Novo Nordisk Foundation.
Breast cancer, with an incidence rate of 25.8 in every 100,000 women, is the commonest cancer among women.
Breast cancer projection for India for 2020 suggests that the number could go as high as 17,97,900. Incidence rates are lower in rural than urban women. According to the national family health survey IV, 3.5 per cent of all women using any family planning method used pills. The survey is based on 2015-16 data.
Among 1.8 million women whose cases were followed on average for 10.9 years, breast cancer occurred in 11,517 cases. The relative risk of breast cancer among all current and recent users of hormonal contraception was 1.20, the article said.
After discontinuation of hormonal contraception, the risk of breast cancer was still higher among women who had used hormonal contraceptives for five years or more than among women who had not used hormonal contraceptives.
Hormonal contraceptives include pills, injectable contraceptives, some intrauterine devices and also morning-after pills.
Dr Ashok Vaid, chairman of medical and haemato oncology at Medanta Medicity, said, “The study basically says that if for a normal woman the risk is 1, for a contraceptive user the risk is 1.20. The researchers also say that there are many factors, for example, they did not have information about variable alcohol consumption. The Danish health registry has data only from 1976. But the take home message to my mind is that if there are alternatives to hormonal contraceptives, a woman should be told about them and choice of hormonal contraceptive should happen with the knowledge of increased breast cancer risk.”