The Pill Linked to Breast Cancer Risk for Younger Women
By Kathryn Doyle
Photo by Monik Marus/Flickr
NEW YORK (Reuters Health) - A new statistical analysis finds that women under age 50 who were diagnosed with breast cancer were also more likely to have recently been on some versions of the Pill.
The increased cancer risk still translates to less than a one percent chance of developing breast cancer for most younger women, researchers emphasize, so the results should not outweigh the many benefits of taking oral contraceptives.
These results are not enough to change clinical practice or to discourage any women from taking birth control pills, said lead study author Elizabeth F. Beaber, of the Fred Hutchinson Cancer Research Center in Seattle, Washington.
Some past research suggests that the hormones in birth control pills could “feed” hormone-sensitive tumors and thereby raise younger women’s risk of a breast cancer diagnosis, or of developing more aggressive cancers.
But birth control pills have evolved over the decades since their introduction and the hormone doses they contain have dropped steadily, so many studies are based on data for formulations that are no longer used, Beaber and her colleagues point out in the journal Cancer Research.
To examine the risk in a group of women more recently on birth control pills, Beaber’s team analyzed data from a large healthcare delivery system, tracking birth control pill prescriptions and breast cancer diagnoses.
The researchers compared 1,102 women diagnosed with invasive breast cancer between 1990 and 2009 with 21,952 women without cancer who were of similar age.
Women who had taken oral contraception during the past year, according to pharmacy records, were more likely to be in the cancer group than those who had never taken birth control pills or who had taken them more than a year prior.
Contraceptives with higher doses of estrogen or progestin were more strongly associated with increased cancer risk.