Adjuvant therapy with gemcitabine and stereotactic body radiation therapy versus gemcitabine alone for resected stage II pancreatic cancer: a prospective, randomized, open-label, single center trial

BACKGROUND: The role of adjuvant radiation in pancreatic adenocarcinoma (PDAC) remains unclear. We aimed to investigate the efficacy of gemcitabine combined with stereotactic body radiation therapy (SBRT) as adjuvant therapy for resected stage II PDAC. METHODS: In this single-center randomized controlled trial, patients with stage II PDAC that underwent margin-negative resection were randomly assigned to gemcitabine-alone adjuvant chemotherapy or adjuvant SBRT followed by gemcitabine chemotherapy. The primary endpoint was recurrence-free survival (RFS). Secondary endpoints included locoregional recurrence-free survival (LRFS), overall survival (OS), and incidence of adverse events. RESULTS: Forty patients were randomly assigned to treatment between Sep 1, 2015 and Mar 31, 2018. Of these, 38 were included in the intention-to-treat analysis (20 in gemcitabine arm and 18 in gemcitabine plus SBRT arm). The median RFS and OS were 9.70, 28.0 months in the gemcitabine arm and 5.30, 15.0 months in the gemcitabine plus SBRT arm (RFS, P = 0.53; OS, P = 0.20), respectively. The median LRFS in both arms was unreached (P = 0.81). Grade 3 or 4 adverse events were all comparable between the two arms. Evaluation of data from the enrolled patients indicated that the addition of adjuvant SBRT was not associated with either better local disease control or recurrence-free survival. CONCLUSIONS: Adjuvant SBRT neither provided a survival benefit nor improved local disease control in resected stage II PDAC. TRIAL REGISTRATION: ClinicalTrials.gov, NCT02461836. Registered 03/06/2015