Mucinous carcinoma of the colon and rectum comprised 35 (6.5%) of 540 cases of colorectal carcinoma. The clinical and pathological features of these mucinous carcinomas were compared with those of 478 well- and moderately differentiated adenocarcinomas.
Mucinous carcinoma was more common in those under 39 years of age (p<0.05) and tended to be more frequent in female patients. The greatest number of cases of mucinous carcinoma were located in the rectum, followed by the right colon. The ralative incidence, however, was high in the right colon (40.0% versus 12.1%, p<0.005). Mucinous carcinoma was characterized by infiltration to the surrounding tissues (25.7% versus 7.9%, p<0.005), positive lymph node involvement (74.3% versus 48.7%, p<0.005), and peritoneal implant (22.9% versus 4.0%, p<0.005).
The cumulative 5- and 10-year survival rates after resection of mucinous carcinoma were 46.9% and 41.0%, respectively; those after curative resection of mucinous carcinoma were 69.1% and 60.5%, respectively. These survival rates were lower, but not significantly, than those for well- and moderately differentiated adenocarcinoma.
The results suggest the need for aggressive lymph node dissection and wide excision of the surrounding tissues for mucinous carcinoma, with special attention given to local recurrence.