The pathologist's role in the diagnosis and therapy of rectal cancer

The pathologist's role in the diagnosis and therapy of rectal cancer is reviewed. Basically, it concerns the diagnosis established at biopsy, the staging and the definition of prognostic factors. The biopsy-proven diagnosis confirms the clinical or radiologic diagnosis of malignancy while the histological type and grading is also assessed. The latter includes three levels and is based on the tubular clumping of neoplastic cells. The most commonly used staging systems: Dukes' classification, TNM, and Jass' system are presented. The staging aspects which impact on prognosis are stressed. Particular attention is paid to the specific problems of preoperative radiochemotherapy which frequently affects the initial grading and staging. Finally, the role the pathologist plays in the definition of histopathologic prognostic factors complementary to the conventional morphological study, is underlined.