Philadelphia, PA, October 15, 2007 Using a model to predict reductions in death from colorectal cancer, epidemiologists and clinical researchers from Memorial Sloan-Kettering looked at the relative effect of an initial screening colonoscopy which clears pre-cancerous polyps from the colon versus surveillance follow-up colonoscopy. Ann G. Zauber, Ph.D., Sidney J. Winawer, M.D., MACG and colleagues presented their findings at the Annual Scientific Meeting of the American College of Gastroenterology.
The model demonstrated a dramatic reduction in expected colorectal cancer mortality with initial polypectomy with or without surveillance, and suggests that the initial polypectomy accounts for the major component of the mortality reduction, explained Dr. Zauber.
Using a MISCAN model, researchers used National Polyp Study data to predict colorectal cancer mortality among three groups of patients: those with no initial removal of polyps or follow-up surveillance by colonoscopy, compared to patients with only initial polypectomy, and those with both polypectomy and follow-up surveillance. The model predicted mortality of up to thirty years after the initial colorectal exam and removal of pre-cancerous polyps.
According to Dr. Zauber, the major effect on colorectal cancer mortality reduction produced by the initial polypectomy rather than the surveillance colonoscopies is consistent with the low incidence of advanced adenomas observed during National Polyp Study (NPS) follow-up (i.e., pre-cancerous growths in the colon larger than 1 cm, polyps with a villous component, high grade dysplasia or invasive colorectal cancer.)
Dr. Zauber and her colleagues suggest that these findings may support the recommendation to lengthen the interval to six or more years for follow-up surveillance for patients who have polyps removed. Current recommendations by the American College of Gastroenterology call for surveillance colonoscopy in three
|Contact: Rosanne Riesenman|
American College of Gastroenterology