Full-dose gemcitabine is a more effective chemotherapeutic agent than 5-fluorouracil for concurrent chemoradiotherapy as first-line treatment in locally advanced pancreatic cancer

Objectives: To compare the efficacy of full-dose gemcitabine-based concurrent chemoradiotherapy (FG-CCRT) and conventional 5-fluorouracil CCRT (5FU-CCRT) for locally advanced pancreatic cancer (LAPC). Methods: 109 LAPC cases treated with FG-CCRT (n = 89) or 5FU-CCRT (n = 20) were reviewed retrospectively. The FG-CCRT group was composed of a full-dose gemcitabine monotherapy (1,000 mg/m²) arm and a combination therapy with cisplatin (70 mg/m²) arm. The 5FU-CCRT group used a radiosensitizing dose of 5-FU (500 mg/m²) plus leucovorin (20 mg/m²). Concurrent radiotherapy was targeted at the tumor with a 5-mm margin without lymph node irradiation. Results: Objective response rate (ORR) and disease control rate (DCR) was significantly higher in the FG-CCRT group (ORR: 32.6 vs. 5%, p = 0.013; DCR: 79.8 vs. 50.0%, p = 0.006). FG-CCRT showed remarkable superiority to 5FU-CCRT for suppressing distant metastasis (18.0 vs. 45.0%, p = 0.017). Neutropenia (34.8 vs. 10%, p = 0.032) and thrombocytopenia (21.3 vs. 0.0%, p = 0.021) were more frequent in the FG-CCRT group as originally expected. When dividing the FG-CCRT group to gemcitabine monotherapy (GEM) and gemcitabine plus cisplatin, toxicities of the GEM subgroup were not different than those of the 5FU-CCRT group. Conclusion: FG-CCRT, especially full-dose gemcitabine monotherapy-based CCRT was more effective for the initial control of LAPC than 5FU-CCRT, and also relatively safe.