Anal epidermoid carcinoma: a population-based clinico-pathological study of 164 patients.

The clinical and pathological features of 164 patients with anal epidermoid carcinoma were investigated in a population-based study between 1978 and 1984. Twenty-three tumours, the majority of which were small and well differentiated squamous cell carcinomas, were situated in the perianal region. Twenty of these patients are alive and disease-free. Of 141 tumours in the anal canal two-thirds were of the cloacogenic type, i.e. displaying transitional cell differentiation. The overall 5-year survival was between 40 and 50% for both cloacogenic and squamous cell carcinomas, respectively. However, poorly differentiated squamous cell carcinomas and cloacogenic carcinomas without any squamous cell differentiation (subtype A) had a more aggressive course, especially in men, than the other subgroups. Clinical stage also had an impact on prognosis. Both stage, sex, degree of differentiation and histologic subtypes revealed independent prognostic information. Although the primary aim of this study was not to evaluate therapy, it was noted that patients primarily treated with irradiation (with or without chemotherapy) had a more favourable course than patients treated with surgery alone.