Influence of radiation therapy on cure and recurrence rates

Radiation alone has produced modest reductions in the rates of pelvic failure after curative resection of rectal cancer, but has had little effect on survival rates. Trials of higher radiation doses near normal tissue tolerance levels have not yet been completed. Because of the frequency of extrapelvic metastases many studies currently incorporate both chemotherapy and radiation therapy although the long-term benefits of such combinations are not yet known. Radiation and more limited surgical procedures may allow preservation of anorectal function and be an alternative to abdominoperineal and similar excisions. At present selection criteria are not sufficiently developed to allow exclusion of many patients who do not require multimodality therapy.