We analyzed the interrelations of sex, age, tumor site, Dukes' stage, growth pattern and differentiation, and their prognostic value in 293 patients with primary colorectal adenocarcinoma. Simultaneously, growth pattern, differentiation, DNA and S-phase fraction (SPF) in paired primary tumors and lymph node metastases from 97 colorectal cancer patients were compared. The results revealed that poorly differentiated and mucinous tumors, as against well/moderately differentiated tumors, were frequently located in the proximal colon, and their frequencies were increased as Dukes' stage advanced (p=0.03). Tumor differentiation was usually identical in primaries and corresponding metastases (p=0.002), but this was not true of tumor growth pattern, DNA ploidy or SPF. In multivariate survival analyses, Dukes' stage provided strongly prognostic information (p<0.001) and mucinous tumors tended to predict worse survival (p=0.08).