Pain response of patients treated with radiotherapy for painful bone metastases between 2013 and 2024 - An analysis of the prospective real-world PRESENT cohort

Objectives: This study aimed to evaluate the pain response following external beam radiotherapy (EBRT) in a large real-world cohort of patients with painful bone metastases. Methods: Patients receiving EBRT were enrolled in a prospective cohort. Pain scores and analgesic use were collected at baseline and until 12 weeks post-treatment. Pain response was defined as ≥ 2-point pain reduction (on 0–10 scale) without increased pain medication, or ≥ 25 % opioid reduction without pain increase. Logistic regression analyses were performed based on primary tumor type, baseline pain severity, baseline performance status, metastasis location, and treatment period. Survival was analyzed with the Kaplan-Meier method. Results: Of 2363 patients enrolled between June 2013 and July 2024, 2067 (87%) were included for analyses. Seventy percent (n = 1442) of these analyzable patients experienced complete or partial pain response. The average pain score decreased from 5.9 at baseline to 3.7 at twelve weeks post-treatment. Patients with prostate or breast cancer and those with baseline pain scores ≥ 5 showed higher response rates (75%, 76%, and 73%, respectively). The pain response rate slightly increased from 67% (95%CI, 63–71) to 73% (95%CI, 69–77) (p = 0.037) over the last eleven years. Patients with pain response had longer median survival than non-responders (14 versus 6 months, p < 0.001). Conclusions: Approximately 70% of patients with painful bone metastases experience a partial or complete pain response after radiotherapy. Over the past decade, the pain response rate improved slightly from 67 to 73%.