S1072
Clinical – Upper GI
ESTRO 2026
Medical Physics and Biomedical Engineering, UCL, London, United Kingdom
This study aimed to evaluate the efficacy and safety of combining endostar and envafolimab with concurrent chemoradiotherapy in patients with unresectable locally advanced esophageal squamous cell carcinoma (LA-ESCC). Material/Methods: Patients with histologically confirmed LA-ESCC were enrolled. Prior to enrollment, radiologists evaluated each patient to exclude the risk of esophageal fistula. Treatment involved involved-field radiotherapy at a dose of 50.4 Gy (1.8 Gy per fraction, once daily), two cycles of paclitaxel liposome (150 mg/m ² ) and carboplatin (AUC = 5) administered every 4 weeks, and five cycles of endostar (75 mg via 48-hour infusion, once weekly). Envafolimab (400 mg) was administered subcutaneously every 4 weeks, starting concurrently with chemoradiotherapy and continued for up to 12 cycles. The primary endpoint was progression-free survival (PFS). Secondary endpoints included the objective response rate (ORR) and the rate of endoscopic complete remission (EsCR), defined as the absence of invasive carcinoma on esophagoscopic biopsy. Results: Between September 2021 and March 2023, 35 patients were enrolled. The ORR assessed by PET-CT was 97.1%, and the EsCR rate was 77.1%. The median PFS was 21.5 months, with a 24-month PFS rate of 48.6%. The 24-month overall survival (OS) rate was 74.3%, and the median OS was 41.5 months. The most frequent grade 3 or higher treatment-related adverse events (TRAEs) were leukopenia, neutropenia, and thrombocytopenia. Pneumonitis occurred in one patient (2.7%). One patient had esophageal fistula and 1 patient died of massive hemorrhage after radiotherapy. There were no treatment-related deaths or treatment discontinuations due to serious adverse events. Conclusion: The combination of envafolimab, endostar, and concurrent chemoradiotherapy was well-tolerated and demonstrated promising efficacy in patients with LA- ESCC. The risk of esophageal fistula and bleeding should be fully assessed before treatment. Keywords: chemoradiotherapy, immunotherapy, target therapy Digital Poster 1294 Characteristics and early toxicity outcomes of definitive proton chemoradiotherapy for esophageal cancer patients with fragile lungs Elina K Cook 1,2 , Douglas Brand 2 , Maria Hawkins 2,3 1 Radiation Medicine Program, Princess Margaret Cancer Centre, Toronto, Canada. 2 Clinical Oncology, UCLH, London, United Kingdom. 3 Department of
Purpose/Objective: Comorbid fibrotic lung conditions, particularly subtypes of interstitial lung disease (ILD) such as idiopathic pulmonary fibrosis (IPF), are associated with high morbidity and mortality after thoracic radiotherapy [1]. The risk of radiation pneumonitis with ILD remains high with esophageal cancer radiotherapy [2], with added concerns for heart toxicity due to increased burden of comorbid cardiovascular conditions [3]. Proton therapy can spare lung and heart from irradiation. We hypothesized that treating esophageal cancer patients with high-risk pulmonary conditions with definitive chemoradiation using proton beam therapy (PBT) would enable low rates of toxicity. Material/Methods: PBT referrals to University College London Hospitals (UCLH) were tracked April 2023 – October 2025. Radical PBT was defined as 50Gy in 25 fractions with systemic therapy. Plan dosimetry, toxicity data (acute to 6 weeks and late >6 weeks) and outcomes were collected from patient charts. Data was analyzed using SPSS v31. Results: 17 patients with esophageal cancer meeting PBT eligibility criteria with frail lungs were referred to UCLH for PBT, and 15 were treated with concurrent chemoradiation. Demographics, staging, lung function and dosimetry are summarized in Table 1. Notably, most had ILD, 20% had IPF, and normal tissue dose was low (Figure 1 shows an example of sparing in an IPF case). Follow up data was available (median six months, range two weeks to 15 months) for 11 treated cases (four were still on treatment). There were no documented cases of radiation pneumonitis nor cardiac complications to date, and 91% of patients completed all fractions. Three deaths occurred at two weeks, six months and 11 months post chemoradiation from chest infection (systemic sclerosis), unrelated sepsis (scleroderma), and pneumonia and suspected esophageal-pericardial fistula (systemic sclerosis), respectively, all with baseline ILD-GAP scores 0-3. Two cases (IPF, COPD) had a hospital admission >6 months due to lung infections. The worst acute toxicities were grade 3, consisting of radiation dermatitis (one systemic sclerosis case), dysphagia (one case), and pulmonary embolism (one case).
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