ESTRO 2025 - Abstract Book

S1820

Clinical – Upper GI

ESTRO 2025

3246

Digital Poster Preoperative chemoradiotherapy for esophageal and esophagogastric junction carcinoma: Single institutional results utilizing an extended CROSS regimen Tobias Haltmeier 1 , Jennifer Brazerol 2 , Martin D. Berger 3 , Yves Borbély 1 , Anna Stenger-Weisser 2,4 , Burim Sermaxhaj 2,5 , Hossein Hemmatazad 2 1 Department of Visceral Surgery and Medicine, Inselspital, Bern University Hospital, Bern, Switzerland. 2 Department of Radiation Oncology, Inselspital, Bern University Hospital, Bern, Switzerland. 3 Department of Medical Oncology, Inselspital, Bern University Hospital, Bern, Switzerland. 4 Department of Radiation Oncology, Kantonsspital Luzern, Lucerne, Switzerland. 5 Department of Radiation Oncology, Stadtspital Triemli, Zurich, Zurich, Switzerland Purpose/Objective: Despite advancements in treatment, the survival rates for locally advanced esophageal cancer (EC) remain low. CROSS trial demonstrated increased survival rates with preoperative chemoradiotherapy (CRT) using 41.4 Gy and weekly carboplatin/paclitaxel. At our institution, we implemented an extended form of CROSS treatment scheme with radiation dose escalation to 50.4 Gy. The aim of this study was to investigate the oncological outcomes and toxicity profiles of our neo-adjuvant treatment regime in comparison to the existing literature, particularly the CROSS trial. Material/Methods: This retrospective observational study focused on patients with esophageal cancer who underwent neoadjuvant chemoradiotherapy (NA-CRT) followed by surgical tumor resection at a tertiary care university hospital between 2014 and 2018. The study included patients with histopathologically confirmed adenocarcinoma (AC) or squamous cell carcinoma (SCC) of the esophagus or esophagogastric junction, with a tumor stage greater than T1 and/or nodal-positive disease NA-RCT was performed using a modified CROSS protocol with 28 x 1.8 Gy (50.4 Gy in total) and weekly chemotherapy with carboplatin/paclitaxel. The effect of the radiation dose and histopathological complete response on mortality was assessed in multivariable Cox regression analysis, adjusting for clinically important variables, including sex, age, American Society of Anesthesiologists (ASA) physical status classification system score, tumor and nodal stage, and the histological tumor type. Results: A total of 46 patients were included. Median age was 67 years (IQR 9) and 36 patients (78.3%) were male. In 90.7% an ASA score >= 3 was reported. The tumor stage (cT) was >= 3 in 38 patients (82.6%). The endosonographic nodal stage (uN) was positive in 42 patients (91.3%). Pathological complete response was found in 7/42 patients (16.7%). Median survival time was 2.7 years (95%CI 0.700- 1.340). In multivariable Cox regression analysis, pathological complete response was associated with significantly lower mortality over time (OR 0.152, 95%CI 0.202-1.115). For higher radiation volumes, multivariable regression revealed a trend towards increased mortality, although not statistically significant (radiation volume/100: OR 1.172, 95%CI 0.987-1.392). Conclusion: In comparison to the results of the CROSS trial, the dose escalation for radiation therapy (50.4 Gy in total) was not associated with a higher rate of pathological complete response or a survival benefit in patients with resectable EC. However, multivariable analysis revealed a trend towards increased mortality in association with higher radiation volumes. Therefore, using modern radiotherapy techniques such as online adaptive radiotherapy might be more beneficial instead of escalating the radiation dose.

Keywords: Esophageal cancer, dose escalation