Adjuvant postoperative therapy of gastrointestinal malignancies.

Postoperative treatment with adjuvant chemotherapy with or without radiation has been extensively studied in cancers of the gastrointestinal tract. Clinical trials of adjuvant postoperative chemotherapy in gastric cancer have failed to show a survival benefit, and although studies in pancreatic cancer suggest a benefit for postoperative concurrent chemoradiotherapy, confirmatory trials have not been performed. In contrast, adjuvant therapy for cancers of the colon and rectum has been shown to improve survival in patients at significant risk for disease recurrence. For Dukes' C colon cancer, postoperative adjuvant chemotherapy with a combination of fluorouracil and levamisole is now recommended as standard therapy. Recent studies suggest that adjuvant therapy with fluorouracil plus leucovorin also improves disease-free survival; longer follow-up is needed to assess effects on overall survival. For Dukes' B2 and C rectal cancer, standard therapy is postoperative treatment with fluorouracil-based chemotherapy and concurrent pelvic radiotherapy.