U.N. Research Agency Determines Hormone Therapy Regimen Slightly Raises Risk of Some Cancers

In late July 2005, the International Agency for Research on Cancer —  the United Nations’ cancer agency  — announced its new determination that hormonal menopausal therapy causes cancer.  This IARC announcement was quick to point out, however, that their new determination does not mean that the millions of women around the world who are on a hormone therapy regimen should automatically stop the treatment.

"It’s a complicated picture," said Vincent Cogliano, head of IARC’s monographs department. "It doesn’t mean women should stop taking the treatment. There are still other reasons to take it. Each woman has to discuss it with her doctor and weigh the risks and benefits."

This IARC monograph on hormone therapy and cancer was published on July 29, 2005. It has reclassified hormonal menopause therapy from "possibly carcinogenic to humans" to "carcinogenic to humans" based on consistent evidence emerging from studies over the past few years.  According to the IARC monograph, various medical studies have shown that hormonal menopause therapy slightly increases a woman’s risks of breast cancer and endometrial cancer.

This July 2005 IARC monograph pointed out, also, that oral contraceptive pills, or birth control pills, which are taken by about ten percent of women in their reproductive years, cause more types of cancer than previously thought.  Previously, the contraceptive pills had been identified as causing liver cancer. According to IARC, more recent research has demonstrated that this birth control pill slightly increases a woman’s risks of breast cancer and cervical cancer, also. On the other hand, IARC’s investigation revealed that the birth control pill decreases a woman’s risks of endometrial cancer and ovarian cancer.

(Posted by: Tom Lamb)