Prediction of outcome after curative resection for large bowel cancer.

Prospectively collected information on 2524 patients who had undergone "curative" resection for colorectal cancer was analysed to establish the rank-order of importance of both clinical and pathological factors affecting outcome. The patients were divided into two groups. In the first, a statistical weighting was established for each prognostic factor and those that influenced long-term survival were, in order of importance, lymph node status, tumour mobility, number of lymph nodes positive for tumour, presence of bowel obstruction, and depth of primary tumour penetration. Factors that influenced in-hospital mortality were cardiopulmonary complications, intraabdominal sepsis (without anastomotic leak), presence of bowel obstruction, and age. In the second group these mathematical weightings were applied, and the predicted and observed outcomes were in close agreement. Statistical techniques of this kind will be of value in prognosis and in analysis of the results of new treatment regimens.