Original broadcast date: January 18, 2009

Colorectal Cancer is the second leading cause of cancer deaths in North America. Screening is essential to catch the disease in its early stages. From a clinical standpoint colonoscopy is considered to be the gold standard for evaluation of the colon. There is a caveat introduced into this interpretation. A new study published in the January 6, 2009 issue of the Annals of Internal Medicine indeed finds that colonoscopy is strongly associated with fewer deaths from colorectal cancer. However, the risk reduction appears to be entirely due to a reduction in deaths from left-sided cancers. According to the study, colonoscopy shows almost no mortality prevention benefit for cancer that develops in the right side of the colon.

• Dr. Nancy Baxter, MD, PhD, Colorectal Surgeon at St. Michael’s and a Research scientist at the Keenan Research Centre of the Li Ka Shing Knowledge Institute, St. Michael’s Hospital.  She is Assistant Professor in the Departments of Surgery and Health Policy, Management and Evaluation at the University of Toronto and Adjunct Scientist, Cancer Theme Group at the Institute for Clinical Evaluative Sciences and lead study author.