Endoscopic ultrasonography in the staging and follow-up of epidermoid carcinoma of the anal canal.

Epidermoid (squamous cell) carcinomas of the anal canal are relatively rare, accounting for less than 3% of all malignant tumors affecting the large intestine. Radiation therapy alone or combined with chemotherapy is the treatment of choice. To be effective, this requires initially correct staging and accurate follow-up. Endoscopic ultrasonography plays an essential role, which, during a period of 20 months, we applied to 20 patients. This made possible initial staging according to the TNM classification system. Follow-up examinations showed reduction in size of lesions in all cases. Three patients required early post-radiation surgical intervention because of rectal or vaginal invasion or lymph node metastases. Recurrence in 3 patients, evident by mural expansion on consecutive ultrasound examinations, was diagnosed at 6, 10, and 12 months. In all 6 patients requiring surgical intervention, good correlation was observed between ultrasonic images and operative findings.