Weight loss in overweight or obese breast cancer survivors reduces hormonal factors that influence the risk of cancer recurrence

This study investigated how weight loss affects hormonal factors in breast cancer survivors. The levels of hormones which are thought to increase the risk of recurrence were compared before and after weight loss.

Overweight status and obesity have been shown to increase the risk of recurrence and lower survival in breast cancer survivors. This increase in risk is thought to be influenced by changes in the levels of hormones such as leptin (a hormone produced by fatty tissues which plays a role in fat storage), insulin (a hormone that helps the body use glucose as energy), estrogen (the main female sex hormone), and sex hormone binding globulin or SHBG (a protein that binds to sex hormones and blocks their actions in the body). The hormones leptin, insulin, and estrogen increase directly as a result of excess weight. Furthermore, SHBG decreases, contributing to high estrogen levels. It is not clear, however, whether weight loss can reverse these hormonal changes and reduce these risk factors in breast cancer survivors.

Researchers collected data from a previous study of 258 overweight or obese breast cancer survivors. Patients were previously diagnosed with breast cancer, but had completed all treatments. All patients were included in a supervised weight loss program and had leptin, insulin, estrogen and SHBG levels measured before starting the program and after 6 and 18 months.

A 5% weight loss was shown to be associated with reductions in leptin and insulin and an increase in SHBG. This also led to a reduction in estrogen levels in post-menopausal patients. A weight loss of more than 5% reduced hormonal risk factors for breast cancer recurrence even more significantly.

Weight loss of 5% or more significantly reduced several hormonal risk factors for breast cancer recurrence and mortality.

While this study showed significant results in respect to hormonal factors, how this change affects outcome and recurrence was not directly investigated but only assumed. Further follow up for these patients is necessary in order to determine long-term outcomes.

Consult with your doctor about achieving a healthy weight to reduce your risk for breast cancer recurrence.