Intraoperative electron beam radiation therapy with particular reference to the treatment of rectal carcinomas--primary and recurrent

Radiation therapy is being used alone or in combination with surgery with increasing frequency in the treatment of colorectal malignancies. Preoperative or postoperative irradiation may be offered to patients with marginally resectable lesions who are at high risk for local recurrence. Dose levels required for cure, however, may be such that the complications are unacceptable. The use of intraoperative radiation therapy (IORT) has increased the possibility of a higher local control rate and possible cure. The ability to increase the therapeutic ratio between local control and complications using IORT is achieved only with close interaction between the surgeon and radiation oncologist. Furthermore, intraoperative radiation therapy may be offered for patients with recurrent rectal tumors. The technique of intraoperative radiation therapy will be described briefly and recent results regarding colorectal cancers from larger centers will be reviewed. It appears from many reports that the three-to-five-year results for marginally resectable disease are approximately 50 percent and for recurrent disease, approximately 40 percent. The incidence of complications following intraoperative radiation therapy does not appear to increase as a result of this aggressive treatment modality. The number of centers offering this modality is increasing rapidly.