Factors Associated with and Characteristics of Patients Receiving Proton Therapy at the End Of Life

Purpose To identify the characteristics, indications, and toxicities among patients receiving proton beam therapy (PBT) in the final year of life at an academic medical center. Materials and methods A retrospective review of patients who received PBT within the final 12 months of life was performed. Electronic medical records were reviewed for patient and treatment details from 2010-2019. Patients were followed from start of PBT until death or last follow-up. Acute (3 months) toxicities were graded using the CTCAE v5.0. Imaging response was assessed using the RECIST v1.1. Chi-square test was used to evaluate factors associated with palliative treatment. Simple logistic regression was used to evaluate factors associated with toxicity. Results Bet299 patients were treated at the end of life (EOL) out of 5802 total patients treated with PBT (5.2%). Median age was 68 years (19-94 years), 58% male. The most common cancer was non-small cell lung cancer (27%). Patients were treated for symptom palliation alone (11%), durable control (57%), curative intent (16%), local recurrence (14%), or oligometastatic disease (2%). Forty-five percent received reirradiation. Median treatment time was 32 days (1-189 days). Acute toxicity was noted in 85% of patients (31% G1, 53% G2, 15% G3). Thirteen patients (4%) experienced chronic toxicity. Breast and hematologic malignancy were associated with palliative intent χ2 (1, N=14) = 17, p=0.013; (χ2 (1, N=14) = 18, p=0.009). Conclusion The number of patients treated with PBT at the EOL was low compared to allcomers. Many of these patients received treatment with definitive doses and concurrent systemic therapy. Some patients spent a large portion of their remaining days on treatment. A prognostic indicator may better optimize patient selection for PBT at the EOL.