ASCO - Raloxifene May Protect Against Endometrial Cancer

By Megan Rauscher

ORLANDO MAY 17, 2005 (Reuters Health) - A population-based case-control study shows that raloxifene may reduce the risk of endometrial cancer and confirms that tamoxifen increases the risk of endometrial cancer.

At the 41st annual meeting of the American Society of Clinical Oncology, Dr. Angela DeMichele of the University of Pennsylvania, Philadelphia, noted that raloxifene, in contrast to tamoxifen, does not stimulate endometrial estrogen receptors and may therefore be associated with a lower risk of endometrial cancer than tamoxifen.

To investigate, Dr. DeMichele and her colleagues compared raloxifene and tamoxifen use among 511 women with endometrial cancer and 1410 controls with no history of endometrial cancer.

"In multivariate analysis, users of raloxifene had half the risk of endometrial cancer as nonusers, which is highly significant," Dr. DeMichele said. The adjusted odds ratio for endometrial cancer with raloxifene use was 0.50.

The protective effect of raloxifene was "most striking" in those using it for less than 3 years, with an adjusted odds ratio of 0.41.  "Protection continued with longer use but it was not as striking," Dr. DeMichele reported. 

In contrast, "users of tamoxifen had a 50% increased risk of developing endometrial cancer," according to Dr. DeMichele, with an adjusted odds ratio of 1.5.  In this study, however, this "did not reach statistical significance," she said.

Summing up, Dr. DeMichele noted that endometrial cancer is the most common gynecologic cancer, making it important cancer for chemoprevention strategies.  "If raloxifene proves effective at preventing both breast cancer and endometrial cancer, that information could weigh heavily on a woman"s decision about which drug to choose," she said.


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