1 Metachronous carcinomas in colorectum and its clinicopathological significance

PUROPOSE: The study was designed to examine the significance of colorectal metachronous carcinoma in a large cohort of patients. METHODS: Over a mean follow-up period of 10 years, the clinicopathological features, microsatellite instability (MSI) and clinical follow-up of 56 patients with metachronous colorectal carcinoma were analysed. RESULTS: The prevalence of metachronous colorectal carcinoma was 2.1%. The metachronous colorectal carcinomas appeared between 7 to 246 months (mean=66 months) after surgical resection of the index colorectal carcinomas. Thirty-six per cent (n=20) of the metachronous carcinoma occurred more than 5 years after the operation of the index carcinoma. Of the 56 patients, 20 % (n=11) of the metachronous colorectal carcinomas were mucinous adenocarcinoma. Cancers detected in the secondary operations (metachronous colorectal carcinomas), when compared with the primary index cancers, were smaller, showed higher proportions of mucinous adenocarcinoma and more often located in the proximal colon. Patients wit