Epidermoid carcinoma of the anal canal. A series of 276 cases.

During the past ten years, substantial progress has been made in the knowledge of the natural history of epidermoid carcinoma of the anal canal and of the response of the disease to radiotherapy alone or combined with chemotherapy. At the present time, the main problem in the management of this tumor concerns identification of the best modalities to achieve local control and preservation of anal function. From a series of 276 cases, followed for more than three years, the necessity for a careful pretreatment evaluation was stressed. This included a systematic search for pelvic metastatic lymph nodes by palpation and CT scan. All patients were treated initially by irradiation except those who underwent groin dissection for inguinal node metastasis or colostomy for complete anal obstruction. Three groups of patients have been identified: unresectable or disseminated tumors (33 cases), resectable tumors but not suitable for sphincter conservation (21 cases) treated by radiochemotherapy and delayed surgery, and resectable tumors suitable for sphincter conservation (222 cases) which were treated by a split-course regimen combining a short course of carefully planned external beam irradiation (19 days) followed by an iridium 192 implant after a two-month rest. In this group, which represents 80 percent of the whole series, 80 percent of patients have had their cancer controlled and 90 percent of controlled patients have retained normal anal function. The use of chemotherapy during the first days of irradiation is advisable in all cases to reinforce the efficacy of treatment and increase the chance of anal preservation. Results of the split-course regimen, combining external beam and interstitial irradiation, demonstrate a clear superiority over external beam irradiation alone, especially for large infiltrating tumors, which represent the majority of cases.