There has been a rapid increase in the number of 1-and 2-room proton beam therapy (PBT) centers. While this increases patient access to PBT, individual centers with 1-or 2-rooms may be limited in the number of patients that can be treated. The objective of this study was to analyze the impact of a clinical scoring algorithm, termed the 'clinical benefit score' (CBS), which was utilized as a method for patient prioritization for PBT at an NCI-designated comprehensive-cancer center operating in a 'cost-neutral' proton-photon payer environment, where the charges for proton or IMRT/VMAT radiotherapy (RT) are identical. Materials/Methods: This study includes patients considered for PBT within a network consisting of 4 photon centers and 1 PBT center that initially had only 1-2 treatment rooms available for clinical use. Any patient considered a candidate for PBT was prospectively scored using the CBS, which consisted of the following variables: age, clinical-site of treatment, re-irradiation, clinical trial participation, dosimetric factors, and patient-specific risk-factors for RT-toxicity. Patients with a higher CBS were prioritized for treatment, but were only scheduled for PBT once insurance approval for PBT was obtained. The outcome was receipt of PBT. The main variable was CBS. Other data collected included sex, race, and Medicare status. Crude and adjusted analyses were performed using logistic regression. Results: During the study period, 2163 patients were evaluated for radiation therapy. A total of 205 patients (9.5%) were deemed candidates for PBT, which was received by 122 (59.5%) patients. In patients considered for PBT, the mean CBS was 18.7 (19.7 for those who were treated vs. 17.3 for those not treated with PBT, pZ0.11). Patients who were <21years old, female, non-white, receiving re-treatment and those with Medicare had a higher CBS. Univariate analysis found no significant association of CBS on the odds of receiving PBT (ORZ1.02, 95%CIZ0.99-1.05, pZ0.11). However, multivariate analysis adjusting for insurance status revealed both CBS and insurance to be significant predictors for PBT. Specifically, a 1 unit increase in CBS was associated with a 4% increased odds of receiving PBT (ORZ1.04, 95%CI-1.01-1.07, pZ0.0145) and having Medicare was associated with 3.13 times higher odds of receiving PBT (ORZ3.13, 95%CIZ1.57-6.26, pZ0.0012). Subgroup analysis, which only included patients enrolled prior to opening the 2 nd gantry, showed a 5% increased odds of receiving PBT per unit increase in CBS (ORZ1.05, 95% CIZ1.00-1.10, pZ0.03) and 2.87 times higher odds of receiving PBT in patients with Medicare (ORZ2.87, 95%CIZ1.04-7.92, pZ0.04). Conclusion: The CBS utilized in this study was significantly associated with receipt of PBT in a cost-neutral payer setting. Physicians at PBT centers with 1 or 2 treatment rooms should consider use of the CBS as a resource allocation tool.
