CHROMOSOME 18Q ALLELIC LOSS AND PROGNOSIS IN STAGE-II AND STAGE-III COLON-CANCER

The prognostic significance of chromosome 18q allelic loss was evaluat ed in a series of 118 patients with curatively resected TNM stage II o r stage III colon cancer. Chromosome 18q status was determined on froz en tumour samples, using microsatellite markers and the polymerase cha in reaction (PCR). Mean follow-up in surviving patients was 75.9 month s. Chromosome 18q allelic loss was significantly related to tumour sit e, extramural venous invasion, flow cytometric nuclear DNA content and p53 protein expression. Patients whose tumour had no evidence of chro mosome 18q allelic loss showed a better disease-free and overall survi val than patients whose tumour demonstrated 18q allelic loss. When pat ients were stratified by tumour stage, a significant survival advantag e for patients whose tumour had no allelic loss on chromosome 18q was observed in stage II as well as in stage III disease. In particular, p atients with stage II disease whose tumour had no chromosome 18q allel ic loss demonstrated an excellent clinical outcome, with a 5-year dise ase-free survival rate of 96%. In contrast, the 5-year disease-free su rvival rate of patients with stage II disease and chromosome 18q allel ic loss was only 54%. In multivariate analysis, status of chromosome 1 8q was the only significant independent prognostic factor for both dis ease-free and overall survival. These results indicate that assessment of chromosome 18q status provides relevant prognostic information in colon cancer and might be employed in the selection of patients for ad juvant therapy. Int. J. Cancer (Pred. Oncol.) 79:390-395,1998. (C) 199 8 Wiley-Liss, Inc.