Energy in and Energy out: What Matters for Survivors of Colorectal Cancer?

It has long been known that obesity increases the risk of type 2 diabetes and cardiovascular disease, but only in the past decade has it become widely accepted that obesity is also one of the risk factors for various cancers, including colorectal cancer.1,2 Renehan et al3 analyzed 29 data sets including 37,334 patients and reported that every 5 kg/m2 increase in body mass index (BMI) was associated with 24% higher incidence of both colon and rectal cancer in men and 9% higher incidence of colon cancer in women. Despite the consistency of the data associating adiposity with colorectal cancer development,4–6 the impact of obesity on mortality among patients with colorectal cancer is less clear.7–13 Some of the variability in the results seems related to the timing of BMI measurements (prediagnosis, at the time of diagnosis, postdiagnosis), potential gender interactions, site of cancer (colon v rectum), and stage of cancer. Mehr