[Colorectal metachronous tumors]

The metachronous colorectal carcinoma is defined as a primary carcinoma which arises after surgical removal of a previous carcinoma of the large bowel. The incidence of metachronous colorectal cancer has been reported to be 1-8 per cent.

The purpose of the present study was to determine the incidence of metachronous colorectal carcinoma and, on this basis, to propose a follow-up programme after primary resection for cure in this patient group of patients.

Twenty-eight patients with metachronous colorectal malignancies underwent surgery, 16 (57.1%) male and 12 (42.9%) female. These metachronous cancers were discovered at intervals ranging from eight months to seven years (range 28 +/- 10 months). Nine (32%) metachronous lesions were detected two years of more after the original cancer. Six of the metachronous cancers appeared in the right colon, eight were distributed throughout the transverse and descending colon, and fourteen in the rectosigmoid region. Histological examination revealed a high proportion of early stage lesions (82.1% Duke's A more B).

A set of patients surviving their initial colorectal cancer should be followed for the rest of their life because of the risk of developing a second primary. In the light of our experience, a full examination of the colon in these patients is mandatory, and colonoscopy is the best diagnostic procedure.