Clinicopathological studies on pm-colorectal carcinoma

During the 13 years from 1978 to 1990, 50 cases of colorectal cancer, infiltrating to the proper muscle layer, were experienced, and were evaluated on the basis of clinicopathological findings. Pm colorectal carcinoma were classified into two groups (pm1,pm2) according to the depth of invasion into the proper muscle layer. Most of the pm colorectal carcinomas were located in the rectum (64%). According to macroscopic classification, the ulcerative type occurred more often (84%) than the elevated type (16%). As the carcinoma invaded deeper into the proper muscle layer, the incidence of lymphatic vessel invasion tended to become higher. Lymphnode metastasis from the ulcerative type cancer (26.2%) was less frequent than that of the elevated type (62.5%). Lymphnode metastasis from the elevated type cancer was confined to the n2 lymphnode. On the other hand, lymphnode metastasis from the ulcerative type had invaded to the n3 lymphnode. These findings indicated that R3 operation is needed for pm colorectal cancer of both the elevated and the ulcerative type, although nerve preserving operation or selective lateral lymphnode dissection is reasonable for pm rectal cancer