Estrogen levels remained more than double in obese women than in women of lower weight, even after treatment with first-line therapies for more than 75 percent of breast cancers—drugs that block the production or action of estrogen.
This news is not to disparage women who have higher weight. This research, published July 16 in the Journal of Clinical Oncology, can lead to improvements in doctors’ ability to select the most appropriate and successful treatment for all women.
What is obesity?
Obesity means having too much body fat. Obese women have higher levels of estrogen than women with lower weight.
Obesity is not the same as being overweight, which means weighing too much. A person may be overweight from extra muscle, bone, or water, as well as from having too much fat.
Obesity and breast cancer
Obese women have higher levels of estrogen than women with lower weight, and most breast cancers thrive in estrogen-rich environments.
The estrogen-suppressing drugs significantly reduced estrogen levels in obese women – but their levels still remained more than double that of women of lower weight. Scientists emphasize that women taking breast cancer treatment should not be concerned by the findings.
“Our findings are based on laboratory studies, so we would need to carry out clinical trials to tell us whether women with a higher BMI would benefit from changes to their treatment. Women with higher BMIs should certainly not be alarmed by this finding or stop taking their treatment. Our study takes us a step closer to understanding which of the treatment options available might be the most suitable for individual women,” said Senior researcher Professor Mitch Dowsett.
The study was led by researchers from The Institute of Cancer Research in London, one the world’s leading cancer research centers, and The Royal Marsden NHS Foundation Trust.