Adjuvant postoperative radiation therapy for colorectal carcinoma above the peritoneal reflection. II. Antimesenteric wall ascending and descending colon and cecum.

From 1970 to 1981, 50 patients had curative surgery for carcinoma of the cecum, ascending, or descending colon and were Stage greater than or equal to B2. In 15 cases, the lesion originated on the antimesenteric (posterolateral) bowel wall. Of seven cases (with minimum three-year follow-up) not receiving adjuvant postoperative regional irradiation, four recurred in the tumor bed/abdominal wall versus 0/3 irradiated patients. Similarly, the five-year survival was improved in the irradiated group (2/3) versus only 2/9 in the unirradiated group. Patients with transmural extension of right or left colon cancers originating on the anti mesenteric (posterolateral) bowel wall may have a high incidence of postoperative regional failure which may be decreased by adjuvant postoperative regional irradiation.