Role of Endoscopy in Screening and Treatment of Gastrointestinal Cancer

Abstract

Gastrointestinal cancer includes tumors of the proximal and distal stomach which are explored by upper GI endoscopy, using a flexible endoscope. It includes also tumors of the large bowel (colon and rectum), explored with flexible endoscopes by a complete colonoscopy or by a simple sigmoidoscopy. In 2008 the number of incident cases occurring in the World is estimated at 988 602 for gastric cancer and at 1 235 108 for colorectal cancer. A trigger role is played by Helicobacter pylori infection in gastric cancer, and by Diet, Nutrition and physical activity, in colorectal cancer. Gastric cancer is more frequent in developing countries of Asia and Latin America; colorectal cancer is more frequent in more developed countries of North America and Europe. For both tumors, endoscopic diagnosis is based on a 2 steps analysis, with detection followed by charaterization and prediction of histology, before decision of endoscopic resection. Techniques of endoscopic resection include polypectomy with a ligating snare, and modalities of resection called EMR and ESD. Endoscopic diagnosis with eventual treatment is the final step of all screening strategies, either in organized mass screening under the control of Health Authorities, or in Opportunistic screening in individual cases. In mass screening, endoscopy is performed only in persons with a positive filter test. In opportunistic screening endoscopy is a primary procedure. In secondary prevention of cancer, the early treatment of the tumor has a positive impact on survival and mortality. In the colorectum the treatment of premalignant adenomatous polyps has an impact on the reduction of incidence and could be considered as a primary prevention.