ESTRO 2025 - Abstract Book

S1065

Clinical – Head & neck

ESTRO 2025

,disease, and survival outcomes were collected prospectively. Reasons for palliative intent, treatment breaks, acute toxicity, symptom relief, and treatment response after RT were retrospectively abstracted from medical records. Overall survival (OS), cause-specific survival (CSS), and locoregional control (LRC) was compared between cohorts with < vs ≥ median overall treatment time (OTT). Multivariable analysis identified prognostic factors for OS and CSS. Results: A total of 183 patients were included (Table 1). At time of treatment 91% of patients had pain and 5% bleeding. Reasons for palliative intent RT included: bulky tumors considered incurable (n=132), poor performance status or comorbidities (n=27), metastatic disease from HNSCC (n=51) or metastatic concurrent second primary (n=23). 51 (29%) patients had a planned break, 19 (10%) unplanned and 30 (16%) both while 83 (46%) had neither. Median OTT was 31 days. Grade 3 acute toxicity was significantly higher in the OTT <31 vs ≥31-day group (22% vs 16%, p<0.001). Median follow-up was 7.3 months (range 0.1-81.9). Symptom relief was achieved in 96% patients in both OTT cohorts. Patients with OTT <31 vs ≥31 days had similar 1-year LRC (80% vs 75%, p=0.892), but higher OS (58% vs 18%, p<0.001) and CSS (58% vs 31%, p=0.033). On MVA OTT ≥ 31-day and current smoking status (vs nonsmoker) had lower OS while lower OTT was predictive for CSS (Table 2).