Treatment outcomes of proton beam therapy combined with retrograde intra-arterial infusion chemotherapy for locally advanced oral cancer in the elderly

The aim of this study was to evaluate the therapeutic efficacy and safety of proton beam therapy combined with retrograde intra-arterial infusion chemotherapy in elderly patients with locally advanced oral cancer. Between February 2009 and October 2019, 42 oral cancer patients aged ≥75 years were treated with this therapy. Median age was 80 years (range 75–90 years) and the median follow-up duration was 39 months (range 2–106 months). Of the 42 patients, 34 (81%) were diagnosed with stage IV cancer. The 3-year overall survival, local control, progression-free survival, and disease-specific survival rates were 56%, 69%, 32%, and 67%, respectively. Regarding acute toxicities, grade 3 neutropenia was observed in six patients (14%), anaemia in five (12%), acute kidney injury in one (2%), and oral mucositis in 18 (42%). Late toxicities of grade 3 were observed in seven patients: dysphagia in six (14%) and osteonecrosis of the jaw in one (2%). This study showed that proton beam therapy combined with retrograde intra-arterial infusion chemotherapy was effective for elderly patients with oral cancer, and toxicities were tolerable and manageable. The study findings suggest that this therapy is a potential treatment option for elderly oral cancer patients with difficulty in surgery and systemic chemotherapy.