ESTRO 2025 - Abstract Book

S1694

Clinical - Sarcoma & skin cancer & malignant melanoma

ESTRO 2025

Conclusion: Our Pre-op Proton Radiotherapy outcomes are comparable to published data 3 . Pre-op proton radiotherapy had the best LC rates, although the difference was not statistically significant. Safety outcomes were reassuring as well.

Keywords: Ewings Sarcoma, Proton Beam Radiotherapy

References: 1. ZS, Nerella R et al. Cureus. Post-Radiotherapy Complications in Ewing Sarcoma: A Case Report and Literature Review. 2024 Jan 3;16(1):e51579. doi: 10.7759/cureus.51579. PMID: 38313991; PMCID: PMC10836181. 2. Bronk JK et al. Comprehensive radiotherapy for pediatric Ewing Sarcoma: Outcomes of a prospective proton study. Radiother Oncol. 2024 Jun;195:110270. doi: 10.1016/j.radonc.2024.110270. Epub 2024 Apr 5. PMID: 38583721. 3. Lex, Johnathan R. et al. Pelvic Ewing sarcoma: Should all patients receive pre-operative radiotherapy, or should it be delivered selectively? European Journal of Surgical Oncology, Volume 47, Issue 10, 2618 - 2626

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Digital Poster Preliminary clinical results of a phase II trial: SPRINT (Sarcoma Preoperative Radiation with simultaneous INTegrated boost). NCT05761054 Daniela Greto 1 , Mauro Loi 1 , Luisa Caprara 1 , Niccolò Bertini 1 , Marianna Valzano 1 , Marco Banini 1 , Ilaria Bonaparte 1 , Ilaria Morelli 1 , Chiara Mattioli 1 , Carolina Orsatti 1 , Andrea Romei 1 , Pierluigi Bonomo 1 , Viola Salvestrini 1 , Monica Mangoni 1 , Isacco Desideri 1 , Icro Meattini 1 , Gabriele Simontacchi 1 , Domenico Andrea Campanacci 2 , Annarita Palomba 3 , Giuliana Roselli 4 , Lorenzo Livi 1 1 Radiation Oncology, Azienda Ospedaliero Universitaria Careggi, Università di Firenze, Florence, Italy. 2 Department of Orthopaedic Oncology and Reconstructive Surgery, Azienda Ospedaliero Universitaria Careggi, Università di Firenze, Florence, Italy. 3 Histopathology and Molecular Diagnostics, Azienda Ospedaliero Universitaria Careggi, Università di Firenze, Florence, Italy. 4 Radiology, Azienda Ospedaliero Universitaria Careggi, Università di Firenze, Florence, Italy Purpose/Objective: Neoadjuvant radiotherapy in patients with locally advanced soft tissue sarcoma (STS) aims to downstage tumors and improve resectability. R0 resection may not be achievable in tumors located near critical structures, such as the neurovascular bundle (NVB), which can affect local control. The SPRINT trial aims to improve R0 resection rates by incorporating an intensity-modulated radiation therapy (IMRT) boost to areas where planned resection may be suboptimal. We report the pathological and safety data of the first 15 patients enrolled in the trial. Material/Methods: This is a prospective, single-arm, Phase II study enrolling STS patients eligible for surgery. Radiotherapy is delivered in 25 daily fractions, targeting the MRI-based Gross Tumor Volume (GTV) and the tissue at risk for microscopic spread (Clinical Target Volume 1, CTV1) with a total dose of 50 Gy. A Simultaneous Integrated Boost (SIB) is applied to the tumor/dissection plane interface, identified by both a radiation oncologist and a surgeon (Clinical Target Volume 2, CTV2), delivering a dose of 60 Gy. A 0.5 cm margin is added to create the Planning Target Volumes (PTV1, PTV2). Concurrent chemotherapy may be administered for up to 3 cycles. The primary endpoint is the R0 resection rate. Secondary endpoints include the pathological complete response (pCR) rate, objective response rate, overall survival (OS), local and distant progression-free survival (PFS), and both acute and chronic toxicity rates. Pathological complete response (pCR) and near-complete response (pNCR) are defined as necrosis rates of 100% and >90-99%, respectively. Toxicity is recorded using the CTCAE v.5.0.