Postoperative follow-up studies on cancer of the colon and rectum.

We followed up 790 patients with cancer of the colon and rectum treated at our hospital since 1962. The curative resection rate in the rectum and anus was 78 percent but decreased as the distance of the lesion from the anus increased. In the ascending colon the rate was 59.8 percent. The patients undergoing curative resection had a 5 year survival rate of 65 percent and a 10 year survival rate of 45 percent. The closer to the anus, the poorer the prognosis. Prognosis is greatly influenced by the stage at diagnosis. Surgical results have improved annually due to progress in diagnostic and therapeutic procedures. Factors greatly influencing prognosis were the presence of lymph node metastasis, the degree of invasion of the intestinal wall and the site of the primary lesion. Lymph node metastasis was an especially important prognostic factor. In cancer of the rectum primary recurrences were most often found in local sites (66 percent of cases), followed by metastasis to the liver and the lung. However, in cancer of the colon metastasis in both the liver and the peritoneum was observed in 67 percent of the cases. On the basis of these results, methods to prevent local recurrence of cancer of the rectum as well as metastasis to the liver from cancer of the colon must be developed. When extended abdominopelvic wide dissection was performed, the incidence of local recurrence decreased.