[Evaluation of the effectiveness of screening for tumors of the digestive system].

Some features of digestive cancers encourage screening programs, even though no such program has been shown so far effective in reducing mortality rates. The visual inspection of the oral cavity and pharynx, with the addition of flexible endoscopy and, possibly, blue-toluidine staining, can be easily performed by specialists and dentists. The strong association with smoking habits and alcohol consumption favours the organization of screening programs but primary prevention maintains the highest priority. For cancer of the colon-rectum two different screening approaches are under close scrutiny: fecal occult blood testing, on an yearly basis, and once-in-a-life sigmoidoscopy at 55-60 years of age. Only one of five ongoing randomized prospective studies on occult blood testing has reported, so far, a significant reduction, around 33%, of mortality from colorectal cancer, with, however, a large burden of sigmoidoscopies.