Five hundred and twenty seven colorectal carcinomas were reviewed histologically. A multivariate analysis (Cox) was used to test the prognostic importance of certain histological features (invasiveness, inflammatory reaction, and amount of fibrous tissue) at the tumour edge after allowance had been made for clinicopathological stage, tumour site, and histological type and grade. A poorly defined tumour border, lack of inflammatory reaction, and a pronounced fibrosis (desmoplasia) at the tumour edge were associated with unfavourable stage distributions, but each of these features also had an independent effect on prognosis.