Being overweight increases a woman’s risk of ovarian cancer, according to a new comprehensive report.
Ovarian cancer now joins the list of cancers whose risk is increased by carrying excess body fat. That list includes postmenopausal breast cancer, colorectal cancer, endometrial cancer, esophageal cancer, kidney cancer, gallbladder cancer, and pancreatic cancer.
“This is an important finding because it shows a way for women to reduce their chances of getting ovarian cancer. There is so much we don’t know about preventing ovarian cancer, but now we can tell women that keeping to a healthy weight can help protect against this deadly disease,” said Elisa V. Bandera, MD, PhD, Associate Professor of Epidemiology at Rutgers Cancer Institute of New Jersey, New Brunswick, and one of the expert panelists who authored the new report from the American Institute for Cancer Research and World Cancer Research Fund (AICR/WCRF).
This latest report from the AICR/WCRF Continuous Update Project (CUP), “Ovarian Cancer 2014 Report: Food, Nutrition, Physical Activity and the Prevention of Ovarian Cancer,” analyzed 128 population studies that investigated how diet, weight, and activity link to ovarian cancer. The 25 studies that focused on weight included 4 million women, 16,000 of whom developed ovarian cancer.
The report showed a dose-response relationship: a 6% increased risk of developing ovarian cancer for every 5-point increase in body mass index (BMI).
The CUP panel of judges concluded that “greater body fatness (which the Panel interprets to be marked by BMI) is probably a cause of ovarian cancer.” They also found that evidence that developmental factors leading to greater linear growth (marked by adult attained height) are a cause of ovarian cancer is convincing and that the evidence suggesting that lactation protects against ovarian cancer is limited.
One of the expert panelists, Ricardo Uauy, MD, PhD, Professor of Public Health Nutrition at the London School of Hygiene and Tropical Medicine, explained that body fat increases the risk of ovarian and other cancers in complex ways. “Fat tissue is not only the main energy store in our bodies, but it is also metabolically active, producing hormone-like compounds that promote inflammation and specific proteins that can affect cell growth and turnover, thus increasing the risk of some forms of cancer. Being obese or overweight also increases blood levels of insulin and insulin-like growth factors that may promote the growth of cancer cells,” Dr Uauy wrote in a blog.
“This finding is significant for two reasons,” he said. “Firstly, ovarian cancer is both difficult to detect and often deadly, with the chances of the cancer recurring quite high. Secondly, maintaining a healthy body weight offers women a way to reduce the risk of getting the disease.”
Dr Uauy noted that a woman with a family history of ovarian or breast cancer who is taller than most women and who smokes has an increased risk of breast cancer. “However, maintaining a healthy weight represents an important new addition to the arsenal of preventive strategies against ovarian cancer,” he said, especially for an older woman, because most cases of ovarian cancer are diagnosed in women older than 55 years.
The report was published online on March 11, 2014.