Oxaliplatin and Capecitabine-Based Chemoradiotherapy for Gastric Cancer - An Extended Phase I RGIT and AIO Trial

Adjuvant 5-fluorouracil-based chemoradiotherapy has been shown to improve the prognosis of gastric cancer. To optimize these results, in the present study oxaliplatin and capecitabine were used instead of 5-fluorouracil. We sought to determine the maximum tolerated dose and the dose-limiting toxicities (DLT) of these drugs in combination with intensity-modulated radiotherapy. Methods and Materials - Patients with resected adenocarcinoma of the stomach or the gastroesophageal junction were included. They received two cycles of induction chemotherapy (oxaliplatin and capecitabine [XelOx] regimen). Using standard Phase I methodology, patients received 45 Gy in 1.8- Gy fractions either in combination with capecitabine 825 mg m super(-1) twice a day (Dose Level [DL] I) or capecitabine in combination with weekly oxaliplatin 40 or 50 mg m super(-1) (DL II and III). After the completion of chemoradiation, two additional cycles of XelOx were scheduled. Results - A total of 32 patients were recruited. Only 1 of 6 patients evaluable on DL I had DLT. Of the first 6 patients on DL, 1 patient experienced DLT, and 3 of the remaining patients had Grade 3 toxicity. Therefore, DL II was defined as the maximum tolerated dose and a total of 20 patients were treated at this DL. The most frequently observed toxicities (Common Toxicity Criteria Grades 1, 2 and 3) were, respectively, leukocytopenia in 5, 5, and 4 patients; nausea in 3, 7, and 3; and diarrhea in 4, 0, and 1. Conclusions - In summary, capecitabine 825 mg m super(-1) twice a day (Days 1-33) and weekly oxaliplatin 40 mg m super(-1) was safe and tolerable in combination with intensity-modulated radiotherapy. Furthermore, four cycles of XelOx could be applied before and after chemoradiotherapy in two thirds of the patients.