Impact of Performance Status and Comorbidity on Palliative Radiation Treatment Tolerance and End-Of-Life Decision-Making

Abstract Purpose Previous studies indicate the relationship between functional status and comorbidity on overall survival when treating patients with bone and brain metastases. However, the degree to which these findings have been integrated into modern-day practice remains unknown. This study will examine the impact of performance measures, including Karnofsky Performance Status (KPS) and comorbidity, on palliative radiotherapy treatment tolerance and fractionation schedule. The relationship between a shorter fractionation schedule (SFx) and pending mortality will also be examined. Methods and Materials This study included patients treated with palliative intent to the brain or bone between January 1 st , 2016 and June 31 st , 2016. Demographic and medical characteristics collected include KPS [stratified into good (90-100), fair (70-80), and poor (≤60)], socioeconomic status (SES), comorbidity (a binary measure using the ACE-27 scale), site of metastatic disease, and treatment facility. Univariable analyses were performed using the Cox proportional hazards regression model to assess the impact of the variables on prescribed number of fractions [a binary measure, 10 or more (long fractionation schedule - LFx) and fewer than 10 (SFx)] and major treatment interruptions (MTIs), defined as missing ≥3 radiotherapy treatment days or ending treatment prematurely. Results 145 patients were eligible for study inclusion. 95 patients were treated for bony metastatic disease, and 50 patients were treated for brain metastases. High comorbidity (p = 0.029) and both fair (p = 0.051) and poor (p = 0.065) functional status were associated with more frequent MTIs. However, high comorbidity and low KPS were not associated with shorter treatment plans. In addition, patients with an earlier time-to-death were not more likely to receive a SFx (p = 0.871). Conclusion Low KPS and elevated comorbidity scores predict for a poorer prognosis and more frequent MTIs; however, there was no indication that physicians incorporated this information in fractionation scheduling.