Indications for and results of irradiation +/- chemotherapy for rectal cancer

With mobile rectal cancers, surgery alone is insufficient treatment for most patients with high-risk factors of tumour extension beyond the rectal wall, node involvement, or both in conjunction. While single modality adjuvant treatment with pre- or postoperative irradiation can reduce the incidence of local relapse, a statistically significant impact on survival has not been achieved. Combined modality postoperative chemoirradiation has resulted in both improved disease control (local and distant) and improved survival (disease free and overall). Randomized trials are underway in high-risk patients to determine the most optimal combinations of postoperative chemoirradiation and to compare preoperative versus postoperative chemoirradiation. Standard therapy with surgery, external irradiation, and chemotherapy is often unsuccessful for patients with locally advanced primary cancers that are unresectable for cure or locally recurrent cancers. When intraoperative electron irradiation is combined with standard treatment, encouraging trends are seen with regard to improvements in local control and survival in separate analyses from the Mayo Clinic and the Massachusetts General Hospital. More standard use of systemic therapy is needed as a component of treatment, however, in view of high rates of systemic failure in spite of the locally aggressive treatment regimens.