Anti-psychotics may Increase Breast Cancer Risk

Dec. 30, 2002 (Ivanhoe Newswire) -- Drugs used to treat psychotic illnesses and other conditions may increase a woman's chance of getting breast cancer, shows a new study.

In an analysis of more than 100,000 women, researchers from Harvard Medical School linked use of dopamine antagonists and breast cancer.

Breast cancer strikes more than 180,000 women a year in the United States, leading to about 44,000 deaths. Understanding risk factors for the disease is paramount to controlling its incidence. Animal studies have suggested dopamine antagonists, i.e. anti-psychotics, can raise blood levels of prolactin, which has been shown to promote tumor growth in rats. The Food and Drug Administration has required warning labels on these drugs outlining the risks. However, studies linking the drugs and breast cancer in women have been limited.

This study compared breast cancer rates among about 52,000 women who were taking dopamine antagonists for either psychiatric illnesses or other conditions with about 55,000 women who were not taking the drugs. Women on the drugs had about a 16-percent increased risk of breast cancer compared to those not taking them. The link was also dose-related -- women taking larger doses had greater risk.

The researchers believe the risk is significant, but also note it is relatively small. They recommend more study before doctors change treatment strategies for patients taking dopamine antagonists.