Clinical outcome and toxicity of 3D-conformal radiotherapy combined with chemotherapy based on the Intergroup SWOG 9008/INT0116 study protocol for gastric cancer.

PURPOSE: To retrospectively evaluate the efficacy and toxicity of adjuvant radio-chemotherapy in patients with gastric cancer and to relate them to the outcome of the landmark INT0116 study that is criticized because of the high toxicity and poor treatment compliance. METHODS: A total of 102 patients who underwent postoperative fluorouracil (5-FU)-based radio-chemotherapy in our institution between 2004 and 2010 for stage IB-IV (AJCC 6th Edn.) gastric cancer were selected. Radiotherapy to 45 Gy was defined individually and delivered with 3D conformal technique. Chemotherapy was carried out during the first 4 and the last 3 days of radiotherapy with continuous infusion of 5-FU (400mg/m²/day) and leucovorin. Patients received an additional 3 cycles of chemotherapy of 5-FU (425mg/m²/day), mostly 1 before and 2 after radio-chemotherapy. Acute hematological and gastrointestinal toxicities were evaluated according to the CTC v3.0 scale. RESULTS: Stage distribution was as follows: IB-5 (5%), II-32 (31%), III-49 (48%), and IV-14 (14%). There were 96% R0 resections; 15% of the patients had a D2 resection. Seventy-four patients (72.5%) received all 5 planned cycles and 98 (96%) completed radiotherapy. The 3- and 5-year overall survival (OS) rates were 57% and 48%, respectively. Multivariate analysis showed that variables significantly affecting OS were pT3-T4, pN2-3, R1 resection and female gender. Only 2% of the patients experienced grade 3 gastrointestinal toxicity; 7% had grade 3 or higher hematological toxicity. CONCLUSIONS: We demonstrated better treatment tolerance, compliance, OS of adjuvant radio-chemotherapy for gastric cancer in comparison with INT0116 study. Conformal radiation techniques might have contributed to this improvement.