Current issues in the treatment of colorectal cancer.

For colorectal cancers that are confined to the bowel wall with uninvolved nodes, surgery alone is curative in most patients, and adjuvant treatment is usually not indicated. A combined modality approach for the initial treatment of many rectal and selected colonic carcinomas is based on data that "radical" operations do not necessarily prevent either local regrowth or distant failures and acceptance of a significant palliative but infrequent curative role for irradiation and chemotherapy when such failures occur. Published data for rectal cancer indicates that local recurrence can be markedly reduced by moderate to high dose pre- and post-operative irradiation +/- chemotherapy. For colon cancer, data from pilot trials suggest that post-operative irradiation may reduce local recurrence by stage when compared with surgery alone analyses, but randomized trials are needed. With locally advanced disease, aggressive treatment combinations appear to increase both local control and survival, but much interaction is required between involved physicians.