KAUAI, HAWAII – Current or recent use of hormonal contraception is associated with an increased risk of breast cancer, although in response to the Danish study findings.
“The data looks clear. It’s not a big risk, but it’s clearly a higher risk,” Lawrence F. Eichenfield, MD, said at the Hawaii Dermatology Seminar provided by the Global Academy for Medical Education/Skin Disease Education Foundation.
Investigators at the University of Copenhagen conducted a prospective cohort study among all 1.8 million Danish women aged 15-49 years who had not had cancer, venous thromboembolism, or treatment for infertility. Comprehensive nationwide registries were used to follow the women for an average of 10.9 years, which represents 19.6 million person-years of follow-up.
During that time, 11,517 cases of invasive breast cancer occurred in the study population. The relative risk was 1.2-fold greater in current or recent users of hormonal contraception, compared with never users of oral estrogen/progestin contraceptives or progestin-containing intrauterine devices. The risk rose with duration of use: from 1.09-fold with less than 1 year of exposure to 1.38-fold with more than 10 years of hormonal contraception.
From a population standpoint, there were 13 additional breast cancers diagnosed per 100,000 person-years of hormonal contraception use. That worked out to one extra breast cancer for every 7,690 women using hormonal contraception for 1 year ().Dr. Eichenfield pointed out that among Danish patients who used an oral contraceptive for less than 5 years, the excess risk of breast cancer went away within a year of stopping the medication. If patients used hormonal contraception for more than 5 years, the excess breast cancer risk lasted for 5 years after stopping.
He noted that the antiandrogen spironolactone, widely used off-label to treat adult female acne, has been shown to be free of any increased breast cancer risk.
He reported serving as a consultant to and/or recipient of research grants from more than a dozen pharmaceutical companies.
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