Introduction: Predictors of outcome in patients with metastatic colorectal cancer remain inconsistent. We aimed to identify predictors of outcome in these patients, to develop a prognostic scoring system, and to assess the general applicability of the current major risk scoring systems.
Materials and methods: Following IRB approval, medical records of 662 consecutive patients undergoing resection of colorectal metastases to the liver during 1960 to 1995 were reviewed. Clinicopathologic and outcome data were assessed from records and mailed questionnaire. Clinicopathologic variables were tested using univariate and multivariate analyses; best-fit models were then generated to study the effect of each independent risk factor on outcome. To validate existing scoring models, our independent data set was applied to those scores. The relative concordance probability estimates were calculated for these models and compared with that of the proposed Mayo model.
Results: The overall and disease-specific 5-year survival rates were 37% and 42%, respectively. The probability of recurrence at any site was 65% at 5 years. Perioperative blood transfusion and positive hepatoduodenal nodes were the major determinants of survival and recurrence. To assess the general applicability of the proposed risk scoring systems, we imported the data from our patient population into 3 other scoring systems. Neither survival nor recurrence among our patients was stratified discretely by any of the scoring systems. Based on probability estimates, all models were only marginally better than chance alone in predicting outcome.
Conclusion: Broad application of risk scoring systems for patients with metastatic colorectal cancer has limited clinical value and refinement and external validation should be undertaken before utilization.