S1089
Clinical – Upper GI
ESTRO 2026
Digital Poster 2867
model to evaluate their predictive value for heart dose changes, using 10 fold cross validation. Additionally, we assessed the impact of a clinically implemented adaptation protocol, triggered when MHD increased by more than 1.5 Gy. This protocol was applied to 93 patients treated after August 2022, of whom 25 underwent plan adaptation due to increasing MHD. Results: A linear mixed model (LMM) revealed significant increases in MHD (0.4 Gy/week, p < 0.001) and heart V40Gy (4.1 cc/week, p < 0.001) over the treatment course, along with significant trends in dysphagia, internal target volume (ITV), and cranio-caudal heart displacement (Figure 1). Additionally, diaphragm baseline shift showed a significant overall difference from the planning situation. The GBRT model showed diaphragm baseline shifts, heart volume changes, and ITV size as main predictors for MHD changes. The whole group of 200 patients showed an average MHD increase of 0.7 Gy, while in the subgroup of 23 patients who received plan adaptation due to MHD increase, the average MHD increase across all reCTs was reduced from 1.6 Gy to 1.1 Gy (Figure 2). Conclusion: Heart dose increases significantly during the course of IMPT for esophageal cancer. Diaphragm position, heart volume, and tumor regression contribute to this increase. A proactive adaptation protocol based on heart dose monitoring can effectively mitigate these effects.
Feasibility and Safety of Stereotactic Body Radiotherapy (SBRT) in Elderly Patients With Borderline or Locally Advanced Pancreatic Cancer Nunzia Luna Valentina Cernusco 1 , Pier Giorgio Esposito 2 , Giulia Volpi 1 , Alessandra Auriemma 3 , Michele Milella 3 , Carlo Cavedon 2 , Alessandro Muraglia 1 , Eliana La Rocca 1 1 Radiotherapy Unit, Azienda Ospedaliera Universitaria Integrata, Verona, Italy. 2 Medical Physics Unit, Azienda Ospedaliera Universitaria Integrata, Verona, Italy. 3 Oncology Unit, Azienda Ospedaliera Universitaria Integrata, Verona, Italy Purpose/Objective: Pancreatic cancer (PC) in elderly patients poses a clinical challenge due to frequent comorbidities and the limited eligibility for surgical resection. As curative surgery is often not feasible, stereotactic body radiotherapy (SBRT) has emerged as a promising modality. The use of SBRT in older patients, however, remains less clearly defined, and its safety and efficacy warrant further evaluation.This study aimed to evaluate the feasibility, safety, and clinical outcomes of SBRT in patients aged over 75 years with borderline resectable or locally advanced pancreatic cancer. Material/Methods: We retrospectively analyzed elderly patients (> 75 years) treated with SBRT at our institution from 2017 to 2025. Treatment consisted of five fractions, delivering 50 Gy to the tumor-vessel interface, 30 Gy to the gross tumor, and 25 Gy to overlapping regions involving organs at risk. All treatments were performed with volumetric modulated arc therapy (VMAT) using a Varian TrueBeam linear accelerator. Overall survival (OS), local control (LC), and progression-free survival (PFS) were calculated from the start of SBRT using the Kaplan–Meier method. Toxicities were graded according to CTCAE version 5.0. Results: A total of 53 patients were included, with a median age of 78 years (range 75–87). The majority were male (58.5%), and most tumors were located in the pancreatic head (58.8%). Locally advanced disease was observed in 66% of cases. Chemotherapy was administered to 85.6% of patients, most commonly gemcitabine plus nab-paclitaxel (75.6%). All patients completed SBRT as planned, and 33.3% subsequently underwent surgical resection. Two acute severe toxicities occurred (one grade 3 and one grade 5 cholangitis), while no late toxicity of grade ≥ 3 was reported. After a median follow-up of 11.1 months, local control at one and two years was 68.7% and 38.4%, respectively. Median overall survival and progression-free survival were 17.1 and 9.2 months. The one- and two-year overall survival rates were
Keywords: esophagus IMPT, heart, time trends in heart dose
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