2760 - Factors Associated with Non-Completion of Palliative Radiation Therapy in Patients with Metastatic Cancer

Purpose/Objective(s):

Palliative radiation therapy (RT) is used to manage symptoms in patients with advanced cancer. However, a subset of patients do not complete their prescribed course, which may reflect suboptimal patient selection, inappropriate fractionation, or rapid clinical deterioration. Data characterizing this population are scarce. We aimed to describe the incidence, patient characteristics, treatment details, and reasons for non-completion of palliative RT courses at a tertiary cancer center.

Materials/Methods: We performed a retrospective review of all consecutive RT courses prescribed at a dedicated palliative RT clinic at one tertiary center from 2024-2025. Patients who did not complete their prescribed fractionation schedule were identified from a prospective palliative RT database. Data collected included demographics, primary cancer type, ECOG performance status (PS), radiation site, dose/fractionation, reason for discontinuation (death, clinical deterioration, patient preference, or physician decision), receipt of systemic therapy, and vital status at last follow-up. Descriptive statistics were used to summarize the cohort.

Results: Of 1,682 palliative RT courses, 39 (2.3%) were not completed. Of the 39 incomplete RT courses, median age was 65 years (range 37-86); 56% were male. The most common primary cancers were lung (21%), breast (18%), gastrointestinal (18%), head and neck (13%), and prostate (10%). The most common RT site was bone (49%; spine 33%, non-spine 15%), followed by thorax (13%) and head and neck (10%). Of patients who did not complete their RT course, 49% had ECOG PS 3 and 8% had ECOG PS 4. Half were on active systemic therapy at the time of RT. The most common prescribed dose was 20 Gy in 5 fractions (44%), followed by 16 Gy in 2 fractions (13%), and the median delivered dose was 12 Gy in 2 fractions. The most common reasons for non-completion were clinical deterioration (54%), patient preference (21%), and physician decision (13%). Death during treatment accounted for 8% (3/39) of the incomplete RT courses, corresponding to an overall rate of 0.18% among all palliative RT courses. Median overall survival from RT start was 27 days (95% CI 18–55).

Conclusion: Non-completion of palliative RT is uncommon (2.3%); it occurs predominantly in patients with poor performance status. Clinical deterioration was the leading cause. Given the short survival observed in this population, single-fraction or ultra-hypofractionated regimens should be strongly considered for patients with ECOG PS =3, and early goals-of-care discussions should address whether initiating RT is appropriate. Prospective studies incorporating predictive models to optimize patient selection and fractionation for palliative RT are warranted.