Stereotactic body radiation therapy with sequential S-1 for patients with locally advanced pancreatic cancer and poor performance status: An open-label, single-arm, phase 2 trial

The optimal treatment for a particularly neglected group of patients with locally advanced pancreatic cancer (LAPC) and poor performance status, who are usually excluded from most clinical trials, is required. Therefore, we aim to investigate the efficacy and safety of stereotactic body radiation therapy (SBRT) with sequential S-1 for those patients.Eligible patients had histologically and radiographically confirmed LAPC and ECOG performance status of 2 or more points determined by two independent physicians. Radiation doses ranged from 35-40 Gy/5f. S-1 was taken orally, twice daily, at a dose of 80 mg/m2 for 28 days, followed by a 14-day interval, which repeated for 6 cycles and was initiated one month after SBRT. The primary endpoint was 1-year overall survival (OS). The secondary endpoints were OS, progression free survival (PFS), treatment-related toxicity and quality of life. The study was registered at ClinicalTrials.gov: NCT02704143.Sixty-three patients were enrolled. At the time of data cut-off, all patients died. No patients were lost to follow-up. Median follow-up was 15.8 months (95%CI 12.9-18.7 months). One-year OS was noted in 46 of 63 patients (73.0%, 95%CI 67.4%-78.6%). The median OS and PFS was 14.4 (95%CI 13.2-15.6 months) and 10.1 months (95%CI 9.7-10.5 months) respectively. Eighteen patients (28.6%) had grade 3 toxicity. According to Quality of Life Questionnaire-Core 30, significant improvements of abdominal pain were found, and patients with poorer baseline global health status had greater improvement of health status and pain relief after treatment.SBRT with sequential S-1 shows promising efficacy and acceptable toxicity in poor performance status patients with LAPC.