Results of radiation therapy in gastric cancer.

Radiation therapy has been used in the treatment of patients with gastric cancer in two clinical settings: definitive therapy for locally advanced, unresectable tumors and adjuvant therapy following surgery for high-risk disease. For patients with locally advanced, unresectable or subtotally resected gastric carcinoma, radiotherapeutic approaches with and without chemotherapy have been employed, because these tumors appear localized, without clinically detectable metastases. Combined treatment with radiation therapy and chemotherapy appears to prolong survival but rarely results in long-term cure. Although only a modest effect was seen on survival, importantly, these studies established the foundation of contemporary combined-modality therapy and have served to stimulate further clinical investigation in gastric cancer as well as other gastrointestinal disease sites. For patients undergoing resection and lymphadenectomy with curative intent, the development of local or regional failure is common, occurring in 40% to 65% of patients. Sites of local and regional failure following resection include the gastric/tumor bed in 20% to 55%, the anastomosis in 25% to 50%, and the regional nodes in 40% to 50% of patients. Intergroup Trial 0116 (INT 0116), a phase III trial, has recently demonstrated that adjuvant radiation therapy with concurrent and maintenance 5-fluorouracil (5-FU) and leucovorin (LV) reduces local failure and improves survival. Adjuvant therapy is now routinely administered to patients undergoing resection of gastric cancer for high-risk disease. Ongoing trials are now investigating new systemic agents with radiation therapy to establish efficacy compared to 5-FU and LV, as well as evaluating neoadjuvant approaches prior to resection.