Study reveals breast cancer risk to fertility drug users


A controversial, new report is out showing the relationship of fertility drugs to breast cancer. Women using fertility drugs who achieve a 10-plus week pregnancy have a statistically significant increased risk of breast cancer compared to unsuccessfully treated women. Compared to untreated women, there is a comparable risk of breast cancer. For women who used fertility drugs, but did not achieve pregnancy, their risk of breast cancer was significantly reduced from untreated women.

Estrogen plays a role in breast cancer

Estrogen is known to play a role in breast cancer. Ovulation-stimulating fertility drugs temporarily increase estrogen levels. “Our data suggest that exposure to a stimulated pregnancy is enough to undo the reduction in risk associated with a history of exposure to ovulation-stimulating drugs,” the authors wrote in Oxford Journal. They state that the exposure to the fertility drugs may raise risk by modifying breast tissue.

The study results are contradictory

In an accompanying editorial, Louise Brinton, PhD, Division of Cancer Epidemiology and Genetics at the National Cancer Institute, wrote that the findings are hard to understand given the conflicting results from previous tests. She stated that the reduced risk associated with drug usage may be related to the fact that clomiphene is a selective strong receptor modulator (SERM) similar to tamoxifen which is an established chemo-preventative.

Results may relate to a narrow group of women

She also postulates that the increased risk to successfully treated women may be due to increased exposure to ovarian hormones. She points out as well that this study focused on women under the age of 50 and for those women often genetic factors contribute to their cancer. She recommends caution interpreting these results.

Source: MedicalNewsToday, Oxford Journals


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