In order to detect early colon cancer in its nonsymptomatic stage, it is necessary to screen the colon regardless of complaints. About 70% of all cancers and polyps of the large intestine are located in its distal part (sigmoid colon and rectum). Therefore, proctoscopic examination is worthwhile to observe these area. However, some of Japanese have elongated sigmoid colon and a proctoscope is not long enough to observe the entire sigmoid colon of these persons. Therefore, during the last ten months, screening colonoscopy using a flexible sigmoidofiberscope, TCF-1s (O-lympus), was performed to 120 subjects. Age distribution of the patients was 32, under 39-year-old and 88, over 40-year-old. Seventy patients of 120 had some symptoms, whereas 50 had no complaints. Seventy patients who had some complaints were prescribed to take "Boncolon" for their diet and 250cc of magnesium citrate solution, and 50 patients without any complaints were forced to evacuate the bowels with aid of glycerin enema but no limitation of their diet. Almost all parts of sigmoid colon and rectum were visualized clearly without retained stool by both preparation methods. In six cases of advanced cancer and missprepared patients, TCF-1s could not pass through the leisons because of stenosis. Excepting these six cases, 114 cases were succeeded in introducing the scope to the proximal end of the sigmoid colon (sigmoid-descending colon junction) within 2.1 minutes. It took about 5.4-5.7 minutes to examine one case in this study. For the observation of the lower parts of the colon, handling of TCF-ls was easier than the conventional colonoscope. Various diseases could be detected not only in 29 cases (41%) among symptomatic patients but 6 cases (12%) among non-symptomatic patients. Especially, one early cancer was found out among non-symptomatic patients in this series. It is emphasized that the elder age groups must be screened as well as the gastric mass survey, and TCF-ls is very useful for the screening examination of the lower colon.
