ESTRO 2025 - Abstract Book

S1752

Clinical – Upper GI

ESTRO 2025

Purpose/Objective: A high neutrophil-lymphocyte ratio (NLR) has been shown as a predictor of worse survival in esophageal cancer (EC) patients. However, its impact remains unclear for the EC patients who received proton beam therapy (PBT). This study aimed to assess the effect of NLR on survival in EC patients treated with PBT and concurrent chemotherapy. Material/Methods: The data of EC patients who underwent definitive PBT with concurrent chemotherapy between 2013 and 2020 were retrospectively reviewed. The following factors for overall survival (OS) were assessed using univariate and multivariate analyses: age (<70 years vs. ≥70 years); sex (female vs. male); Eastern Cooperative Oncology Group Performance Status (ECOG-PS) (0 vs. ≥1); tumor length (<6 cm vs. ≥6 cm); smoking status (yes vs. no); drinking status (yes vs. no); clinical stage ( Ⅰ vs. Ⅱ - Ⅲ vs. Ⅳ ); T/N/M classification (T1-2 vs. T3-4; N0-2 vs. N3; M0 vs. M1); chemotherapy (concurrent vs. concurrent plus induction/additional); and NLR (<3.02 vs. ≥3.02). To determine the optimal cutoff values for predicting OS, the median value was used for tumor length and receiver operating characteristic curve analysis was applied for NLR. Results: A total of 116 EC patients (median age, 68 years [range, 45-90 years]; female/male, 16/100) were examined. The histology of all EC patients was squamous cell carcinoma. The ECOG-PS of 0/1/2, clinical stage Ⅰ / Ⅱ / Ⅲ / Ⅳ , and NLR of <3.02/≥3.02 were 81/34/1, 30/16/43/27, and 65/51, respectively. The median follow-up and survival follow-up times were 51.2 months (range, 3.0-114.0 months) and 55.6 months (range, 3.0-114.0 months), respectively. The 1- and 3 year OS rates were 89.5% and 82.4%, respectively. In univariate analysis, ECOG-PS of ≥1 (≥1 vs. 0; hazard ratio [HR], 3.76; 95% Confidence Interval [CI], 1.58-8.97; p<0.01), clinical stage Ⅳ (stage Ⅳ vs. stage Ⅱ - Ⅲ ; HR, 3.19; 95%CI, 1.19 8.55; p=0.02), T classification (T3-4 vs. T1-2; HR, 3.44; 95%CI, 1.26-9.40; p=0.02), tumor length of ≥6 cm (≥6 cm vs. <6 cm; HR, 3.60; 95%CI, 1.32-9.85; p=0.01), and NLR of ≥3.02 (≥3.02 vs. <3.02; HR, 4.76; 95%CI, 1.84-12.29; p<0.01) were significantly unfavorable factors for OS. In multivariate analysis, ECOG-PS of ≥1 (HR, 2.60; 95%CI, 1.03-6.58; p=0.04), clinical stage Ⅳ (HR, 3.92; 95%CI, 1.39-11.02; p=0.01), and NLR of ≥3.02 (HR, 3.89; 95%CI, 1.36-11.07; p=0.01) were significantly unfavorable factors for OS. Conclusion: In EC patients who received definitive PBT with concurrent chemotherapy, NLR was one of the significant factors for OS, and a high NLR of ≥3.02 was associated with worse OS.

Keywords: NLR, esophageal cancer, proton beam therapy

603

Digital Poster Assessment of Suitability of PRV Margins Applied to Organs at Risk in Pancreatic Stereotactic Body Radiotherapy Ahmed Eltinay 1,2 , Maxwell Robinson 3,4 , Ben George 5 , James Good 5 , Robert Owens 2 , Somnath Mukherjee 2 , Rebecca Muirhead 2 1 Department of Oncology, Royal Berkshire Hospital NHS Trust, Reading, United Kingdom. 2 Department of Oncology, Churchill Hospital, Oxford University Hospital NHS Trust, Oxford, United Kingdom. 3 Department of Radiotherapy Physics, Churchill Hospital, Oxford University Hospital NHS Trust, Oxford, United Kingdom. 4 Oxford Institute for Radiation Oncology, University of Oxford, Oxford, United Kingdom. 5 Department of Radiotherapy Physics, GenesisCare, Oxford, United Kingdom Purpose/Objective: Pancreatic SBRT has shown improved tumour local control, PFS and is suggestive of an improved OS [1-3]. However, it is often limited by the proximity of GI OARs, such as the stomach, duodenum and bowel, which can move