[Malignant tumors of the anal canal and the anal margin].

81 patients with tumors of the anal canal and anal margin treated at the Cantonal Hospital, Lausanne, during the period January 1942 to June 1974 have been studied. The morbid anatomy of transitional zone and cloacogenic carcinomas, subdivided into basaloid types, is related to the anatomy and histology of the normal anal canal. The average age of the patients was 66.5 years. The incidence of canal tumors was highest in women (71% of cases), but tumors of the anal margin were most frequent in men (75% of cases). The main symptom of anal canal growths in this series of advanced cases was blood on the feces; marginal tumours were associated with anal aching. Cloacogenic carcinomas of the basaloid type have the best prognosis; this is also related to the volume and invasion rate of the tumor, which are features difficult to assess. Melanomas have the worst prognosis; leiomyomas may grow like sarcomas despite their benign histological appearance. 18 patients had inguinal metastases, and only 2 of these are alive 2 1/2 and 3 1/2 years after excision of the rectum; the volume and histological type of the tumor were unrelated to the poor rate of survival. In the light of this experience, rectal amputation is the most effective prodecure for all canal tumors and for most tumors of the margin. Radiotherapy by itself is associated with an unacceptably high risk of actinic proctitis.