ESTRO 2025 - Abstract Book

S1539

Clinical – Mixed sites & palliation

ESTRO 2025

time. For a subset of patients, self-reported pain scores using the Brief Pain Inventory were collected at baseline, 4 weeks, 8 weeks, and 3 months. Pain response was calculated over the 3 months post-treatment period for patients with baseline pain scores >1 and reported for patients receiving hypofractionated and multiple-fraction regimens. Patients achieving a complete (pain score 0) or partial (reduction ≥2 points) response were classified as responders; others were non-responders. Results: A total of 11,495 individual patients were included in this study, receiving 21,280 total treatment regimens. Of these, 6,421 patients (56%) received 1 treatment, 2,794 (24%) 2 treatments and 2,280 (20%) ≥3 treatments. Hypofractionated regimens were the most common (n=16863,79%). Multiple fractions (≥5) were used in 3962 (19%) of the regimens. Additionally, 455 (2%) regimens consisted of <5 fractions but other than 1x8 Gy or 2x8 Gy. Treatment patterns remained relatively stable from 2018 to 2022, with a slight increase in hypofractionated regimens from 2020 onwards (Figure 1). The use of hypofractionated regimens ranged from 70% to 90% between treatment centers. Pain response over the 3 months post treatment did not differ significantly between hypofractionated regimens and multiple- fraction (≥5) regimens (month 3 56% vs. 63%, P=0.406) (Figure 2).