Obesity increases risk of certain ovarian cancers

By David Douglas

NEW YORK (Reuters Health) - Obesity increases the risk of invasive clear cell ovarian cancer, a subcategory of ovarian cancer that is difficult to treat, according to Australian researchers.

In the International Journal of Cancer, Dr. Catherine M. Olsen of the Queensland Institute of Medical Research, Herston, and colleagues note that the association between body mass index (BMI), weight gain and different ovarian cancer subtypes has been unclear.

About 90 percent of all epithelial ovarian cancers fall into one of four subcategories: clear cell, mucinous, which is associated with a poor outlook if advanced; endometrioid ovarian cancer, which has a more favorable outlook; and serous ovarian cancer, the most common type.

All epithelial cancers arise from epithelial cells, rapidly dividing cells that continually renew themselves, making up areas such as the skin, the lining of the intestine and the hair.

To investigate further, the researchers studied data for 1,269 women newly diagnosed with invasive epithelial ovarian cancer, 311 women with borderline ovarian tumors and 1,509 "controls" without ovarian disease.

The team found that obesity was associated with more than twice the risk of clear cell tumors, but not with endometrioid or mucinous tumors. There was no association with invasive serous tumors overall, but obesity was linked with close to three-times the risk of serous peritoneal tumors.

For women with the borderline tumor subtypes, obesity was positively associated with serous tumors

"The study findings," Olsen told Reuters Health, "suggest that obesity may increase a woman's risk of developing some types of ovarian cancer."

"This therefore potentially offers women an opportunity to reduce their risk of ovarian cancer in addition to the numerous other chronic diseases associated with obesity," she concluded.

International Journal of Cancer, July 15, 2008.