Toxicity and survival results of a phase II study investigating the role of postoperative chemoradioimmunotherapy for gastric adenocarcinoma

Background and purpose: to investigate the role of postoperative concomitant chemoradioimmunotherapy in gastric adenocarcinoma patients. Patients and methods: 59 patients, who underwent total or subtotal gastrectomy, with lymph node involvement, positive microscopic surgical margins or serosal involvement were included in the study. Radiotherapy started concomitantly with chemotherapy and levamisole. Extended-field radiotherapy was given to gastric bed and regional lymphatics via two anterior-posterior/posterior-anterior fields. A total dose of 45 Gy in 25 fractions with a fraction size of 1.8 Gy was planned. In 28 patients (48%) with positive surgical margins a 10-Gy boost dose was given to the anastomosis site. An adjuvant i.v. bolus of 450 mg/m2/day 5-fluorouracil (5-FU) was administered concomitantly during the first 3 days and at the 20th day of irradiation. After completion of radiotherapy, i.v. boluses of 450 mg/m2/day 5-FU and 25 mg/m2/day rescuvorin were continued for 6 months once a week. Levamisole 40 mg/day orally was started at the 1st day of radiotherapy and also continued for 6 months. Median follow-up was 37 months (7-112 months). Results: median survival was 23 months. Overall 3- and 5-year survival rates amounted to 35% and 14%, respectively. Median survival of the patients with positive surgical margins was 22 months. The 3- and 5-year locoregional control rates were 59% and 55%, respectively. The most common toxicity was upper gastrointestinal system toxicity, which was observed in 42 patients (71%). Four patients (7%) died on account of early toxic effects, and six (10%) could not complete treatment. Conclusion: although 48% of the study population involved patients with microscopic residual disease, the survival results as a whole were satisfactory. However, due to high toxicity, radiotherapy must be delivered with the most proper techniques along with adequate nutrition and supportive care. (orig.)