Abstract
Methods for early detection of colon cancer curable by endoscopic surgery were evaluated in 156 aged subjects over 70 years old without any symptom or abnormal finding of the abdomen. Barium enema and endoscopy of the colon were performed in all subjects for screening. Morbidity and the detection rates of adenoma and cancer were markedly high (61.5%, 26.9% and 13.5%, respectively), and 30 to 40% of adenoma and cancer were found proximal to the descending colon. When findings of endoscopy and barium enema were compared, the false negative rate by barium enema was 54.4%, which was observed in many cases of polyp and 3 cases of early cancer. A high positive rate of stool occult blood test and high values of tumor marker were found in cancer cases. But, there was no significant difference between neoplastic cases (adenoma and cancer cases) and other cases (non-neoplastic cases and normal subjects). Thus, stool occult blood test and measurement of tumor markers (CEA CA 19-9) were useless for early detection of colon cancer in the aged subjects without abdominal symptoms and abnormal findings, and barium enema as the close examination was also inappropriate because of the high frequency of false negative findings. Therefore, we conclude that endoscopy is the most useful method for screening and treatment and strongly emphasize the importance of total colonoscopy in view of the specificity of development site of cancer in the aged subjects.
