Early Clinical Outcomes of Intensity Modulated Radiation Therapy/Intensity Modulated Proton Therapy Combination in Comparison with Intensity Modulated Radiation Therapy Alone in Oropharynx Cancer Patients

Purpose: To report the early clinical outcomes of combining intensity-modulated radiation therapy (IMRT) and proton (IMPT) in comparison with IMRT alone treating oropharynx cancer (OPC) patients. Materials Methods: The medical records 148 OPC patients who underwent definitive radiotherapy (RT) concurrent systemic therapy, from January 2016 till December 2019 at Samsung Medical Center, were retrospectively reviewed. During 5.5 weeks’ RT course, initial 16 (or 18) fractions delivered by all patients, subsequent 12 10) either 81 (IMRT only) or IMPT 67 (IMRT/IMPT combination), respectively, based on adaptive re-plan profiles availability equipment. Propensity-score matching (PSM) was done 76 (38 each group) for comparative analyses. Results: With median follow-up 24.7 months, there no significant difference overall survival progression free between groups, both before after PSM. Before PSM, IMRT/IMPT combination group experienced grade ? 3 acute toxicities less frequently: mucositis 37.0% 13.4% (p < 0.001); analgesic quantification algorithm (AQA) 19.4% = 0.019), respectively. same trends observed PSM: 39.5% 15.8% 0.021); AQA 47.4% 21.1% 0.016), In multivariate logistic regression, significantly frequent group, PSM 0.027 0.024, respectively). score also 0.085 0.018, Conclusions: comparable oncologic outcomes, more favorable toxicity achieved following than alone.