Degree of differentiation in colorectal adenocarcinomas: a multivariate analysis of the influence on survival.

Three hundred and sixty eight resected colorectal adenocarcinomas were graded (WHO) retrospectively and the results correlated with estimated length of patient survival. In 30 (82%) of the tumours more than one degree of differentiation was found. Histological grade significantly influenced survival time when other explanatory variables such as tumour site and stage, age, and sex were adjusted for. The results suggested that three degrees of differentiation (well, moderate, and poor) are sufficient for the grading of colorectal carcinomas, and that grading should be based on the predominating degree of differentiation represented in the primary tumour.