The future of adjuvant treatment in gastrointestinal cancer.

Adjuvant treatment is based on the concept that surgery is only potentially curative and that apparently localized disease has extended beyond surgical resection or is already disseminated. Although death might be related to local recurrence as well as to disease dissemination, most of the trials have tested only one adjuvant modality. Among many negative and non-contributory studies, very few positive results were obtained: in rectal cancer it seems that pre-operative and perhaps postoperative radiotherapy may reduce the incidence of local recurrences, and in colon cancer patients treated with Methyl-CCNU, vincristine and 5-fluorouracil (5-FU) had a significant increase in survival. In colon cancer, the lack of active drug might at least partly explain negative studies, but in gastric cancer the most active combination in advanced disease has failed to demonstrate an improvement of survival in the adjuvant setting. Future trials should take account of this succession of negative trials.