Breast cancer sufferers who are obese continue to have higher levels of estrogen than women of normal weight even after treatment with hormone-suppressing drugs, raising the possibility that they might benefit from different treatment regimes. The new findings, published in the Journal of Clinical Oncology, could lead to improvements in doctors' ability to select the most appropriate treatment for overweight and obese women.
The majority of breast cancers require estrogen to grow, so one of the main ways of treating the disease is by blocking the hormone's production or action. Obese women have higher levels of estrogen than women of normal weight, and the new findings show that although their estrogen levels are markedly reduced with hormone-suppressing drugs (aromatase inhibitors), the levels are higher than those in similarly treated normal weight women.
"We found that women with higher BMIs had more estrogen remaining in their blood after treatment than healthy-weight women, which is consistent with previous suggestions that aromatase inhibitors might be slightly less effective in these women," noted Professor Mitch Dowsett, a team leader at The Institute of Cancer Research (UK).
The findings are based on laboratory studies, rather than clinical trials, so Dowsett says women with higher BMIs should not be alarmed by this finding or stop being treated. "The effect of obesity was modest and women taking breast cancer treatment should not be concerned by the findings. Our study takes us a step closer to understanding which of the treatment options available might be the most suitable for individual women," he concluded.
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Source: Institute of Cancer Research