Initial Experience With Proton Beam Therapy for Pancreatic Cancer at Shonan Kamakura General Hospital

In Japan, proton beam therapy (PBT) for locally advanced pancreatic cancer was administered under an advanced medical treatment system until 2022; since then, it has been covered by national insurance. Our hospital initiated PBT for pancreatic cancer in July 2022. This study evaluated the clinical outcomes of PBT for pancreatic cancer after the initiation of national insurance coverage and assessed whether our initial experience at our hospital reproduced previously reported results. This study included 10 patients with pancreatic cancer confirmed as inoperable due to locally advanced stage, comorbidity, or refusal to undergo surgery, without distant metastasis. All patients received a total PBT dose of 67.5 Gy (relative biological effectiveness) delivered in 25 fractions. The median follow-up durations for all and surviving patients were 13.9 months (range=3.9-24.6 months) and 19.5 months (range=8.1-24.6 months), respectively. The 1- and 2-year overall survival and local control rates were 70% and 35%, and 89% and 89%, respectively. No grade 3 or higher acute or late non-hematological toxicities associated with PBT were observed. The clinical outcomes at the newly established PBT facility were comparable and reproducible to those observed in patients treated under the previous advanced medical treatment system.