| [ Summary ] |
In recent years, the frequncy at which early colorectal cancer has been detected has increased with the spread of group medical checkups and the progression of techniques for colonoscopy. However, few early rectal cancers can be detected in spite of a great deal of advanced rectal cancer. We compared the clinicopathologcal characteristics of 157 early rectal cancer cases with those of 531 early colon cancer cases. The following results were obtained. 1) Superficial depressed type had a tendency to be mostly distributed in the colon (p=0.06), and nodule aggregating type showed a significantly higher incidence than other types located in the rectum (p<0.05). 2) The average of size of superficial depressed type in the rectum w significantly larger than those lesions in the colon (p<0.01). 3) Submucosal invasion rates for the superficial depressed type in the rectum were significantly higher than for those lesions found in the colon (p<O.Ol). 4) Protruding type and superficial depressed type in the rectum were significantly deeper submucosal invasions than the lesions in the colon (p<O.Ol, p<O.O5). 5) The differentiation of carcinoma in the deepest sites of invasion in the rectum was significantly higher than moderately differetiated adenocarcinoma of the rectum (p<0.05).
These results indicate that small superficial depressed type in the rectum may be overlooked, and that rectal carcinomas are more malignant, deeper submucosal invasions than colonic carcinoma. Therfore, it is important that we make every effort to discover small superficial depressed type in the rectum through chromoscopic observasion, and are careful in diagnosing the degree of invasion when choosing therapies. |