Using Proton Beam Therapy in the Elderly Population: A Snapshot of Current Perception and Practice

PURPOSE: With limited proton therapy (PT) resources, several centers have designed their own decision-making systems for PT slot prioritization. The pediatric population is well recognized for deriving benefits from PT; however, elderly patients are not a focus for PT. When should PT be considered for use in the elderly population? METHODS AND MATERIALS: We performed a pilot survey of 25 international academic radiation oncologists (ROs) who also spend significant amounts of clinical time caring for elderly patients. RESULTS: Of the 12 respondents (48%), 58% used photons only, 17% used protons only, and 25% used photons and protons. Their definition of elderly was age ≥70 years. Geriatric evaluation was not systematic. Hypofractionation (60%) and decrease in total dose (50%) were advocated by half the ROs on the basis of age. Target volumes were similar to those in young patients for 80% of ROs. Organs at risk (OARs) associated with vulnerability and constraints to these OARs were considered different for 40% and 10% of ROs, respectively. Priorities for PT were ranked from highest to lowest as follows: survival, toxicity, quality of life, tumor coverage, locoregional control, patient's wish, dose to vulnerable OARs (oral mucosa, esophagus), quality-adjusted life-years, cost, irradiated volume, and integral dose. All ROs considered elderly patients eligible for accrual in clinical trials. CONCLUSIONS: This snapshot survey showed the current gap between chronological age and eventual PT allocation among some PT centers worldwide. The findings suggest that elderly age may become an even weaker argument against PT in the future. They also point out a lack of a systematic geriatric approach. As PT might be regarded as a relevant therapeutic means in the elderly population to limit the toxicity burden and hospital costs, better guidance to allocate PT for this growing segment of the population is still needed.