Treatment of cancer of the anus.

Abstract

There is a widespread impression that the best results in the treatment of cancer of the anus are obtained by radical surgery, and that radiation has little or no place in the management of this disease. It is the object of this paper to show that, in many cases, radiotherapy is the treatment of choice and that permanent cure, with preservation of the anal sphincter and absence of complications, frequently follows. Cancer of the anus, usually epidermoid in type, is not common. From 1947 to 1954 only 9 new cases were encountered in the Saskatoon Cancer Clinic, representing 4 per cent of 239 new cases of cancer of the rectum seen in that period. This percentage is in accordance with the comparative figures found in large series (4, 6, 8, 16). Most authors advise radical surgery in all types of anal cancer, i. e., abdominoperineal excision (1, 3, 4, 7–10). A few recommend radiation therapy in certain cases (2, 12, 13). Some prefer local excision, usually for small lesions of the anal margin (5, 10, 11). It is generally agreed that the only treatment for involved lymph nodes is surgery. It is useful to classify these tumours according to their site of origin. The first type arises below the dentate line and extends into the peri-anal skin; the second arises in the anal canal, extending up and down; the third, quite rare, infiltrates upward into the rectum and is usually called anorectal cancer. It is also epidermoid in nature. The spread in cancers of the anus of the first type is to the inguinal lymph nodes. Block dissection on the involved side should be carried out only when it is known that secondary involvement has taken place. Though this procedure is often unsuccessful, it is the treatment of choice. It is seldom, if ever, successful when both inguinal regions are involved. Stearns (15) has shown that prophylactic block dissection has no place. Judd and DeTar (7), with commendable candour, arrive at the following conclusions: “⋯ when the nodes were not involved, bilateral dissections were attended by relatively good results. However, when the nodes were involved, none of the patients survived five years, no matter how radical the approach.” The use of local radiation treatment in cancer of the lower anus, therefore, can hardly be claimed to jeopardize the subsequent course, with respect to lymph-node metastases, since the decision as to the performance of block dissection of the groins is in no way affected. The lymphatic spread from cancer of the anal canal is frequently upward to the pararectal, superior rectal, and inferior mesenteric nodes. It must be admitted that only by abdominoperineal resection can the primary tumour and the lymphatic spread be adequately dealt with. In spite of this, some of these cases can be successfully treated with radium implantation.