Reported February 27, 2008 
Second Thoughts on Hormone Therapy
(Ivanhoe Newswire) -- Hormone therapy may make it harder to find breast cancer in women. A new report finds combined hormone therapy seems to increase the risk of women having abnormal mammograms and breast biopsies and may decrease both methods’ effectiveness of detecting breast cancer.

Researchers looked at 16,608 post-menopausal women who participated in the Women’s Health Initiative (WHI) clinical trial, beginning in 1993 through 1998. About half were assigned to receive a combination of estrogen plus progesterone, while the others took a placebo. Each woman had an annual mammogram and breast exam.

Results show 199 women taking the combined hormones and 150 of those taking the placebo developed breast cancer. Mammograms with abnormal results were more common among women taking hormones compared to those taking placebo -- 35 percent versus 23 percent. Those taking hormones also had a four percent greater risk of having an abnormal mammogram after one year and 11 percent greater risk after five years.

The study also found breast biopsies were more common in the hormone group than in the placebo group -- 10 percent versus 6.1 percent.

“Although breast cancers were significantly increased and were diagnosed at higher stages in the combined hormone group, biopsies in that group less frequently diagnosed cancer (14.8 percent vs. 19.6 percent),” the authors write. “After discontinuation of combined hormone therapy, its adverse effect on mammograms modulated but remained significantly different from that of placebo for at least 12 months.”

They conclude using combined hormone therapy for about five years “resulted in more than one in 10 and one in 25 women having otherwise avoidable mammogram abnormalities and breast biopsies, respectively, and compromised the diagnostic performance of both.”

They recommend their findings be taken into consideration when women are considering even short-term combined hormone therapy.


SOURCE: Archives of Internal Medicine, 2008;168:370-377