Obesity Increases Mortality in Colon Cancer Patients

PHILADELPHIA — Postmenopausal women diagnosed with colon cancer may be at increased risk of death if they fail to maintain a healthy body weight before cancer diagnosis, according to a study published in the September 2010 issue of Cancer Epidemiology, Biomarkers & Prevention, a journal of the American Association for Cancer Research.
The researchers found that women considered "underweight" or "obese," or who had increased abdominal obesity prior to cancer diagnosis seemed to face a greater risk of mortality.

"Maintaining a healthy body weight is beneficial for postmenopausal women. This may also be beneficial for those diagnosed with colon cancer later in life. It looks like abdominal obesity may be a useful indicator of higher colon cancer mortality," said Anna E. Prizment, Ph.D., M.P.H., a postdoctoral fellow in the division of epidemiology and community health at the University of Minnesota, Masonic Cancer Center. "It is too early to say whether a decrease in weight characteristics after diagnosis will also decrease mortality risk; at that point it may be too late. Therefore, it's best to maintain a normal, healthy body weight throughout life."

Prizment and colleagues extracted data from the Iowa Women's Health Study, which included 1,096 women diagnosed with colon cancer who were observed over a maximum 20-year period. During that time, 493 died, of which 289 died from colon cancer.
Women classified as obese, with a BMI of at least 30 kg/m2, had a 45 percent increased overall mortality rate. The few women classified as underweight, with a BMI less than 18.5 kg/m2, had an 89 percent increased mortality rate compared to those with normal BMI.
Furthermore, women with high waist-to-hip ratio had a 30 to 40 percent greater risk of colon cancer related death. Prizment said that the "exact mechanisms underlying the link between obesity and higher mortality of colon cancer patients are unknown."