A new study finds obese colon cancer patients are at greater risk for death or recurrent disease compared to those who are within a normal weight range.
The study has been reported in Clinical Cancer Research, a journal of the American Association for Cancer Research.
"Obesity has long been established as a risk factor for cancer, but our study in colon cancer patients shows that obesity predicts a poorer prognosis after the cancer is surgically removed," said Frank A. Sinicrope, M.D., professor of medicine and oncology at the Mayo Clinic in Rochester.
In the study, Sinicrope and colleagues evaluated 4,381 patients with stage II or stage III colon cancer who had received adjuvant chemotherapy in clinical trials. Of these patients, 20 percent were obese.
Obesity was significantly linked with poorer overall survival and was independent of other variables analyzed. The prognostic impact was stronger in men than in women, and men in the highest body mass index category for obesity had a 35 percent increased risk of death compared to normal weight patients. The weaker effect in women is consistent with studies that have shown a lower risk of developing colon cancer in obese women compared to obese men.
"We do not know if this is due to biology or the way we measure obesity," said Sinicrope. "Body mass index is a limited measure and there is evidence that abdominal fat may be a better redictor of colon cancer risk and perhaps prognosis in men than in women. There is also the potential influence of menopausal status and hormone replacement therapy in women."