ESTRO 2025 - Abstract Book

S1869

Clinical – Upper GI

ESTRO 2025

placed near or in the tumor in 79,2% and SABR treatments were planned using VMAT in 79,2% of the patients. The most used regimen was 5 fractions of 10 Gy (58,4%) followed by 5 fractions of 8 Gy (32,4%). No acute toxicity associated with the treatment was observed in 79,59% of patients. The median time to assess radiological response was 6 months using liver CT/PET-CT scan in 87,1% of patients. With a median follow-up of 24 months (range 3-84), median overall survival was 54 months (95% CI: 23,3-84,8). Local control (LC) was achieved 56% at 1 year, sustained throughout f/u in 55,9. Median time to LP was 14 months (95% CI:9,18-18,8). No factors associated with survival or local control were found in either the multivariate or univariate analysis. Conclusion: Despite the high local control rates and significant survival outcomes, the high proportion of patients with prior treatments and diverse clinical backgrounds may have influenced the outcomes, highlighting the need for further research to identify predictors of improved outcomes.

Keywords: SBRT, oligometastases, liver

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Poster Discussion Is surgery in esophageal cancer patients with complete response after neo-adjuvant chemoradiotherapy necessary? Efrat Gur, Kundel Yulia, Dror Limon Radiation oncology, Beilinson hospital, Petah tilva, Israel

Purpose/Objective: The main treatment paradigm for locally advanced esophageal cancer includes neoadjuvant

chemoradiotherapy(nCRT) or perioperative chemotherapy followed by esophagectomy1,2. Several studies have raised the question whether esophagectomy is necessary among patients achieving clinical complete response (cCR) after nCRT, especially in patients with squamous cell carcinoma(scc).Meta-analysis evaluating the usefulness of surgery in patients with complete remission after nCRT showed that nCRT alone has better survival benefit than nCRT plus surgery without significant difference in disease free survival.

Material/Methods: Retrospective study of patients with locally advanced esophageal cancer

admitted to a single tertiary care center from 2013 to 2023. Included patients were those who received CRT followed by surgery and achieved pathological complete response (pCR), compared to those who achieved cCR and continued with surveillance only. Criteria for cCR was tumor resolution on computed tomography. pCR was defined as no residual cancer upon pathological examination of surgery. Overall survival (OS) and disease-free survival (DFS) were compared between patients who received surveillance only after CRT and those who underwent surgery. Data was analyzed using Cox proportional hazard analyses. Results: A total of 252 patients were treated with CRT. Mean age at diagnosis was 68.8, 60% male, 48% adenocarcinoma. 56 (22%) patients achieved cCR of whom 76% had scc. 52 (20.6%) achieved pCR of whom 50% has scc. No survival differences were noted between the surveillance and surgery groups (p=0.27). Even stratified between adenocarcinoma (p=0.85) and squamous cell carcinoma (p=0.22) there was no difference in survival. In Scc, there was a trend in DFS (p=0.06) favoring surgery among patients under the age of 70. No prognostic factor for survival was identified in the multivariable model.