Radiotherapy and brachytherapy for recurrent colorectal cancer

Radical surgical excision of locoregional recurrence of colorectal carcinoma usually produces the best survival and should be attempted whenever possible. However, recurrences are often unresectable; hence palliative local therapy may be indicated. There are several options for the radiation therapy of local, unresectable, recurrent, or metastatic colorectal cancer. Whole pelvis irradiation of 4,000-5,000 cGy followed by a coned-down boost of 1,000-1,500 cGy generally provides good symptomatic palliation in 80-90% of patients, but long-term control or cure is rarely achieved. External beam irradiation of 2,000-3,000 cGy to the whole liver with or without concurrent chemotherapy may be used for palliation of metastatic disease to the liver. A combination of intraoperative radiation therapy applied directly to the tumor bed and external beam irradiation may improve local control and survival rates. Multiple options are available for the intraoperative use of brachytherapy which can deliver high radiation doses to the residual tumor, or tumor bed, sparing normal tissue.