CLINICAL CHARACTERISTICS OF METACHRONOUS COLORECTAL TUMORS

A cancer-registry-based study was conducted to investigate the surviva l patterns associated with metachronous colorectal tumors and to compa re the survival of patients with single and metachronous colorectal tu mors. The study included all 1,396 White patients with metachronous co lorectal tumors diagnosed among 143,283 patients with primary colorect al tumors reported between 1973-1986 to the SEER program. The influenc e on survival of age at diagnosis, site of tumor and stage was evaluat ed by means of multivariate survival analysis, using Cox Proportional Hazards Models. Metachronous tumors developed more often following lef t-colon tumors. Stage distribution of the second tumors was better tha n that of single tumors but 47% of the second tumors were discovered i n regionally-advanced or distant-metastatic stages. Survival from the second tumor diagnosed in the rectum was worse than that of a single t umor in the same stage and site. Only the stage of the second tumor wa s found to influence survival from metachronous tumors. The relatively high rate of diagnosis of advanced second colorectal tumors may refle ct either improper follow-up after the diagnosis of the first tumor, o r more aggressive biological characteristics of the second tumors. (C) 1995 Wiley-Liss, Inc.