Sphincter preservation in rectal cancer. Endocavitary radiation therapy.

Endocavitary radiation therapy (Endo RT) is performed mainly with a contact x-ray tube. Interstitial brachytherapy is a supplementary method to boost the tumor bed. Only strictly selected patients can be treated for cure by Endo RT. More than 1,000 patients have been treated in Europe and North America since 1950. In T1 N0 adenocarcinoma, the primary local control rate is close to 90%. The overall 5-year survival is between 60% and 90% depending on patient selection. Careful follow-up is necessary because the majority of local failures can be salvaged, usually by radical surgery. The main advantages of Endo RT are a fully ambulatory and simple treatment that can be applied even in frail or elderly inoperable patients, a low risk of complications, and an inexpensive treatment. Results show it is possible to perform curative treatment in patients with more advanced rectal carcinoma. With the combination of external-beam radiation therapy and Endo RT in stage T2-3 N0-1 tumors, the primary local control rate is around 70%, and the incidence of severe radiation toxicity is less than 5%. Overall 5-year survival is between 50% and 70%. Endo RT can also be used as an adjuvant treatment after local excision, in the treatment of villous adenomas, and for palliation of advanced inoperable tumors.