Survival in colorectal carcinoma associated with previous extracolonic cancer.

Between 1971 and 1990, 1198 patients presented with a primary colorectal cancer, of whom 70 patients (5.8%) had survived previous extracolonic primary malignancies. Complete data were available on 63 cases (metachronous group) of the 70 patients, who had a total of 67 previous extracolonic cancers. Clinical and pathological characteristics of these cases were identical to the remaining patients with primary colorectal cancer (primary group, n = 1128), except that the former group was significantly older, P < 0.05. In the metachronous group there was a preponderance of breast, female genital, gastric, urological, lung and skin cancers, and the median time to develop a colorectal primary tumour was 7 years. The 5-year overall actuarial survival was better in the metachronous group, log rank test: chi 2 = 4.07, P = 0.04. In the metachronous group, 44 patients who had undergone curative resection were matched with patients with primary colorectal cancer (control group, n = 88) in the ratio of 1:2 based on age, sex, tumour site, Dukes' stage, tumour differentiation, grade of surgeon and date of operation. Comparison between these groups showed a significantly better survival in the former group, log rank test: chi 2 = 5.99, P = 0.01. These results suggest that patients with colorectal cancer and a history of previous extracolonic tumours have similar clinicopathological features as the general colorectal cancer population but have a better survival.