The Impact of Early Palliative Radiation Among Patients Enrolled on Early Phase Clinical Trials

Abstract

Early phase clinical trials (EP-CTs) investigate novel oncology treatment options with the goal of improving response rates, decreasing toxicity, and improving survival. Utilization of palliative radiation (RT) in the EP-CT population is poorly characterized, but greater understanding is needed to aid with optimizing symptom management and extending time on trial.We retrospectively reviewed the electronic health records of consecutive patients enrolled in EP-CTs at our phase I clinical trials center from 2017-2019 to obtain demographic and clinical factors and to evaluate the influence of treatment utilization including the timing of palliative radiation therapy on clinical outcomes, including time on trial, and emergency room visits or hospitalizations.Among 241 patients enrolled on EP-CT (median age 63.2 years [range 23-84.3 years]; 52.7% female, 97.1% metastatic cancer), the most common primary cancer types were gastrointestinal (26.0%), lung (23.6%), and breast (11.6%). Eighty patients (33.2%) received palliative RT with a total of 241 treatment courses [median courses: 2 (range 1 - 21), median fractions: 5 (range 1 - 26)]. The most common sites of palliative RT were the brain (41%), spine (13.8%), and long bone (10%). Approximately half of patients (48.8%) received their first course of palliative RT before EP-CT enrollment versus 47.5% (n = 38) following completion of EP-CT and 3.7% (n = 3) during EP-CT. Median time on EP-CT by timing of first palliative RT treatment was 63 days (pre-EP-CT), 68.5 days (after EP-CT), and 156 days (during EP-CT). Among patients receiving palliative RT before or during EP-CT enrollment, there were fewer ED visits or hospitalizations versus patients who received palliative RT after EP-CT completion (30.1% vs 50.0%, P = 0.042).In a cohort of advanced cancer patients enrolled in EP-CTs, palliative RT was utilized in one-third of patients at some point during their care. Those who received palliative RT prior to or during EP-CT enrollment experienced fewer ED visits and hospitalizations compared to those who received it after EP-CT. While rare, those patients who received palliative RT while on EP-CT experienced a markedly longer time on trial, highlighting the potential benefits of EP-CT trial designs that allow for palliative RT while remaining on study. Additional research is warranted to characterize the impact of palliative RT on the EP-CT trial experience.