Older women who take the breast-cancer drug tamoxifen may have an increased risk of developing diabetes, a recent study suggests. The findings, reported in the medical journal Cancer, do not prove that tamoxifen directly leads to diabetes in some women. But researchers say that for women with known risk factors for diabetes, such as obesity or a family history of the disease, tamoxifen can further the risk.
Of more than 14,000 breast cancer survivors age 65 and up, the study found that 10 percent were diagnosed with diabetes over five years. Those odds were one quarter higher among women who were currently on tamoxifen, versus those who were not.
That increase is small and the findings should not alarm women taking tamoxifen, said study leader Lorraine L. Lipscombe of Women's College Hospital and the University of Toronto in Canada. She said that tamoxifen is an important drug and she doesn't want women to think they should stop taking it.
If tamoxifen does affect the odds of developing diabetes, it may only do so in certain women, according to Lipscombe. She and her colleagues speculate that tamoxifen may boost diabetes risk in women who are already predisposed to the disease.
The National Cancer Institute says the benefits of tamoxifen in treating breast cancer are "firmly established and far outweigh the potential risks."
-source: The medical journal Cancer; the National Cancer Institute; University of Toronto
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