For women who experience breast tenderness after beginning hormone replacement therapy (HRT), the risk for developing breast cancer may be upped considerably – by as much as twofold. The recent study was published in the October 12, 2009 issue of Archives of Internal Medicine.
The study, part of the Women’s Health Initiative, involved some 16,600 women; half of the women were given the hormone combination estrogen−progestin, and the other half took placebo pills. All participants were given mammograms and clinical breast exams at the study’s onset, and women reported breast tenderness at this time and one year later. Instances of breast cancer were recorded for up to 5.6 years.
[A]mong the women who were on HRT, those who experienced new−onset breast tenderness had a 48% greater risk of developing invasive breast cancer than those who did not experience breast tenderness.
Among women who were not experiencing any breast tenderness at the beginning of the study, those who were on the hormone treatment experienced breast tenderness over the coming year three times as often as did women on placebo. Looking at the numbers another way – of those women who experienced “new−onset” breast tenderness, 76% of them had been on HRT, indicating a connection between HRT and breast tenderness.
Though the connection seems substantial, researchers aren’t yet sure of the underlying reason. Lead author Carolyn J. Crandall speculates, “[i]s it because the hormone therapy is causing breast−tissue cells to multiply more rapidly, which causes breast tenderness and at the same time indicates increased cancer risk? We need to figure out what makes certain women more susceptible to developing breast tenderness during hormone therapy than other women.”
The researchers say that more research must be devoted to this relationship, since breast tenderness is experienced by about a quarter of women starting out on HRT and usually goes away fairly quickly. They do say, however, that breast tenderness experienced while on HRT “may be a marker of increased breast cancer risk.” The authors also encourage women who experience breast tenderness to consult their doctors to discuss whether or not continuing the treatment is right for them.