ESTRO 2025 - Abstract Book

S1572

Clinical – Mixed sites & palliation

ESTRO 2025

conducted a phase III trial to evaluate whether esophagus/pharynx-sparing RT can reduce patient-reported dysphagia without compromising ambulatory function.

Material/Methods: A multicenter, randomized, single-blind, phase III clinical trial enrolled patients aged > 18 years, with cervical or thoracic MSCC referred for RT of 1-10 fractions (NCT05109819). Patients were stratified by fractionation and center and randomized 1:1 to either conventional or esophagus/pharynx-sparing Volumetric Arc Therapy (VMAT) or Intensity Modulated Radiotherapy (IMRT). Follow-up consisted of daily PRO-CTCAE assessments for five weeks and weekly evaluations with EQ-5D-5L, EORTC-QLQ-C30, weight, and analgesic use for nine weeks. Co-primary endpoints were peak dysphagia during 5 weeks after treatment start and ambulatory function at 9 weeks (measured by the mobility dimension of EQ-5D- 5L). Patients who completed ≥3 days of questionnaires in at least one week were eligible for analysis of peak dysphagia. Both endpoints were analyzed by Wilcoxon rank-sum test. Secondary endpoints were incidence of dysphagia, primary treatment site re-irradiation, and overall survival (OS). Esophageal dose metrics (Dmax (Gy), D1cm³ (Gy), D2cm³ (Gy)) were tested in a logistic regression model for their association with severe or worse dysphagia. Results: From May 21 to April 24, 188 patients were randomized from two Danish centers (Figure 1). Baseline characteristics were balanced across treatment arms (Table 1). Dysphagia occurred in 63% (25% mild, 17% moderate, 14% severe, 7% very severe) of the control group and 54% (25% mild, 17% moderate, 7% severe, 4% very severe) in the esophagus-sparing group. There was no significant difference in peak dysphagia (p=0.2) or ability to walk (p=0.3) between arms. OS was similar between standard RT (median: 6.5 months, 95% CI: [4.2, 11.7]) and esophagus sparing RT (median: 8.3 months, 95% CI: [6.3, 12.69]) (p=0.5). Re-irradiation rates were 8% in the esophagus-sparing and 10% in the conventional arm. Increasing esophageal dose was significantly associated with risk of severe or worse dysphagia: Dmax (OR 1.08, 95% CI [1.03;1.13]), D1cm³ (OR 1.10, 95% CI [1.04;1.15]), and D2cm³ (OR 1.11, 95% CI [1.05;1.17]).