Prospective Phase I Study of Capecitabine and Oxaliplatin Concurrent with Radiation Therapy for the Treatment of Locally Advanced Pancreatic Adenocarcinoma, and Retrospective Comparison to Concurrent 5-Fluorouracil/Radiation and Gemcitabine/Radiation

Purpose The aims of this study is to determine the maximum tolerated dose of capecitabine and oxaliplatin (CAPOX) delivered concurrent with radiation therapy (RT) in the treatment of locally advanced pancreatic adenocarcinoma and to retrospectively compare outcomes with this regimen to concurrent 5-fluorouracil or capecitabine with RT (5FU-RT) or concurrent gemcitabine-based chemotherapy with RT (GEM-RT). Materials and Methods Twelve patients were enrolled in a phase I study using 50.4 Gy RT concurrent with capecitabine chemotherapy (twice daily, 7 days per week) and oxaliplatin (once weekly during weeks 1, 2, 4, and 5). Capecitabine and oxaliplatin doses were 400 mg/m 2 and 50 mg/m 2 , respectively, at dose level 1; 600 mg/m 2 and 50 mg/m 2 at level 2; and 600 mg/m 2 and 60 mg/m 2 at level 3. A standard dose of gemcitabine was recommended following RT or following surgery (if done). The outcomes of patients treated with this regimen were retrospectively compared to 20 patients treated with 5FU-RT and 30 patients treated with GEM-RT. Results Dose level 3 was tolerated with acceptable toxicity. Survival in patients receiving CAPOX-RT did not differ from GEM-RT or 5FU-RT. Response of the primary tumor was observed in 38% of patients treated with CAPOX-RT, 31% of patients treated with 5FU-RT, and 66% of patients treated with GEM-RT ( p = 0.03 GEM-RT versus 5FU-RT). Conclusions CAPOX-RT has acceptable toxicity. A retrospective comparison shows higher response rate with GEM-RT versus 5FU-RT, but this difference did not translate into improvement in overall survival.