That may sound scary. But Morch and other doctors say it’s important to consider how that additional risk translates in terms of actual cases of breast cancer. The illness is fairly rare among women in the age group studied.
“A 20 percent increase of a very small number is still a very small number,” says Mia Gaudet, an epidemiologist with the American Cancer Society. The risk contributed by hormonal contraception, she says, is similar to the extra breast cancer risk contributed by physical inactivity, excessive weight gain in adulthood, or drinking an average of one or more alcoholic drinks per day.
“The absolute increase in risk [found in the study] is 13 per 100,000 women overall, but only 2 per 100,000 women younger than 35 years of age,” writes epidemiologist David Hunter, of the University of Oxford, in an editorial accompanying the study in NEJM.