Abstract 5427: Weekend radiotherapy for oncologic emergencies: A single-institution analysis of indications and practice patterns.

Abstract Purpose: Oncologic complications can arise that require emergency radiotherapy (RT) outside of standard working hours. This study documents the incidence, indications, RT dose/fractionation and outcomes for patients receiving RT on weekends/scheduled holidays at a single institution. Methods: Patients receiving RT on weekends (Saturday, Sunday, or long weekend holidays) from January 2022 through December 2024 were identified retrospectively. Patient demographics, primary cancer diagnosis, clinical indication, treatment site, dose/fractionation, inpatient status, treatment completion, and survival were collected and analyzed. Results: Over three years, 122 patients received emergency weekend RT. Median age was 67 years (39-98); 63.1% male, 66.4% inpatients. Patients most commonly presented with lung (25.4%), gastrointestinal (23.8%), and hematologic (18.0%) malignancies. The top three indications for emergency weekend RT included spinal cord compression (38.9%), GI bleeding (20.7%), or obstructive airway/lung disease (7.6%). The most common RT regimen was 20 Gy in 5 fractions (80.3%), with most patients receiving two days of treatment (54.1%). Six patients (4.9%) did not complete their course of treatment owing to clinical deterioration. One-month mortality was 13.1% and three-month mortality was 36.9%. Conclusions: Weekend RT is predominantly used to manage well-identified oncologic emergencies such as spinal cord compression and tumor-related bleeding. The high inpatient proportion and substantial short-term mortality reflect advanced disease burden requiring urgent intervention. These findings demonstrate the importance and incidence of weekend radiotherapy services and provide evidence to help inform staffing & resource allocation as well as institutional policies. Citation Format: Ahmed Allibhai, Asiyah Allibhai, . Weekend radiotherapy for oncologic emergencies: A single-institution analysis of indications and practice patterns [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl):Abstract nr 5427.