Early-stage rectal cancers may be treated either with endocavitary irradiation alone or transanal excision. Tumors that may be somewhat less favorable are often treated with a transanal excision combined with either preoperative or postoperative radiation therapy. More advanced rectal cancers require removal of part or all of the rectum. If at all possible, only part of the rectum is removed and a permanent colostomy is avoided. Before any treatment is started, the recommended treatment, the reasons it is recommended, the procedures to be carried out, the expected or possible side effects or complications, and the expected benefits are all explained to the patient and family.
Radiation therapy is more effective and better tolerated if given before the operation.
The surgery in these situations generally takes place approximately a month after completion of external-beam radiation therapy. If at the time of the operation it appears that there may be areas at high risk for tumor remaining, it is possible to perform intraoperative brachytherapy where catheters are placed into the tumor bed and then afterloaded with radioactive isotopes. This provides a boost dose of radiation to the tumor bed without exceeding the radiation tolerance of the small intestine, thus reducing the risk of a complication such as a bowel obstruction. University of Florida Treatment Results for Patients with Rectal Cancer Conservative treatment of rectal adenocarcinoma with endocavitary irradiation or wide local excision and postoperative irradiation. By Mendenhall WM, Rout WR, Vauthey JN, Haigh LS, Zlotecki RA, Copeland EM 3rd.