Risk factors of local recurrence of colorectal cancer: a multivariate study.

BACKGROUND/AIMS: Duke's staging is still the most widely used parameter in the estimation of risk for local recurrence in patients with colorectal neoplasia. The aim of this study is to identify biological determinants that may be of use in segregating patients with similarly staged tumors into groups with different risk of local recurrence. METHODOLOGY: Ninety-eight patients who had undergone curative resection for colorectal cancer between 1989 and 1991 were prospectively studied. Statistical analysis of clinical and pathologic variables was carried out using a Cox multivariate proportional hazard model. RESULTS: Dukes stage and DNA ploidy were the only significantly predictive variables for local recurrence. In particular, the factors increasing local recurrence risk were seen to be the presence of lymph node metastases and aneuploid status. In the absence of both of these negative prognostic factors the risk of local recurrence is practically nil, in the presence of just one it reaches 16% and in the presence of both it rises to over 40%. CONCLUSIONS: The results of this study indicate that the presence of an aneuploid tumor with positive lymph nodes places patients at a higher risk of local recurrence, and calls for post-operative adjuvant therapy and intensive follow-up.