Endoanal ultrasonography in the follow-up of anal carcinoma.

As the modern treatment for anal carcinoma is either radiotherapy alone or combined radiochemotherapy, an exact histological staging is impossible. Therefore we have to depend on an accurate preoperative staging method. Endoanal ultrasonography enables imaging of the normal anal canal and its pathologies. In a prospective investigation we were able to confirm the histological proven diagnosis of an anal epidermoid carcinoma in 12 patients with a 10-MHz transducer covered with a sonolucent plastic cone. The depth of infiltration can be determined in relation to the normal layers of the anal canal. Six patients treated with radiotherapy alone or combined radiochemotherapy were followed and the success or failure of the treatment was documented. Endosonography of the anal canal allows an exact staging of a primary anal carcinoma and the follow-up in irradiated carcinomas. Besides digital palpation and proctoscopy with biopsy, endosonography complements the preoperative staging of anal carcinomas.