Is obesity associated with advanced stage or grade of colon cancer?

Population-based studies from Europe have suggested that obesity is associated with more advanced stage colorectal cancer on presentation. Obesity is an even more prevalent issue in North America, but comparable data on associations with cancer are lacking. We reviewed the cases of 672 patients with colon cancer diagnosed between 2004 and 2008 in the province of Manitoba who underwent surgical resection at a Winnipeg Regional Health Authority-affiliated hospital. We tested if obesity was associated with more advanced cancer stage or grade. On multivariate analysis, after adjusting for age, sex, tumour location and socioeconomic status, we were unable to show any significant associations between body mass index of 30 or more and advanced stage or grade cancer on presentation. The reasons for the lack of association are likely multifactorial, including the pathophysiology of the disease and process factors, such as screening habits and colonoscopic diagnostic success rates in obese patients.