S1039
Clinical – Sarcoma, skin cancer, malignant melanoma
ESTRO 2026
1 Radiation Oncology, Fondazione IRCCS Istituto Nazionale Dei Tumori, Milan, Italy. 2 Medical Physics, Fondazione IRCCS Istituto Nazionale Dei Tumori, Milan, Italy. 3 Biostatistics for Clinical Research, Fondazione IRCCS Istituto Nazionale Dei Tumori, Milan, Italy. 4 Medical Oncoloy, Fondazione IRCCS Istituto Nazionale Dei Tumori, Milan, Italy. 5 Breast Unit, Fondazione IRCCS Istituto Nazionale Dei Tumori, Milan, Italy. 6 Pathology, Fondazione IRCCS Istituto Nazionale Dei Tumori, Milan, Italy. 7 Plastic Surgery, Fondazione IRCCS Istituto Nazionale Dei Tumori, Milan, Italy. 8 Sarcoma surgery, Fondazione IRCCS Istituto Nazionale Dei Tumori, Milan, Italy
( ≤ 3 months) and late (>3 months) toxicities were graded according to CTCAE v5.0. Local recurrence-free survival (LRFS) and metastasis-free survival (MFS) were evaluated by imaging, and overall survival (OS) was estimated using the Kaplan-Meier method.IMRT/VMAT with SIB was delivered in 15 consecutive fractions:Tumor bed (SIB): total dose (TD) 48.75 Gy, daily dose (DD) 3.25 Gy. The biologically equivalent dose (EQD2), calculated with α / β = 1, was 64 Gy for negative surgical margins and 68 Gy for positive margins.CTV1 (tumor bed margin): TD 43.9 Gy, DD 2.93 Gy (EQD2 54 Gy).CTV2 (surgical scar): TD 41.8 Gy, DD 2.79 Gy (EQD2 50 Gy). Results: Average age was 55 years; 47.1% female and 52.9% male. Median follow-up was 43± 17 months (range: 1.4-100 months). Tumor locations: lower limbs (54.9%), trunk (25.5%), upper limbs (19.6%). Most common stages were IIIA and II. Main histologies: liposarcoma and spindle cell sarcoma. Positive margins in 17.6%; negative in 82.4%. Adjuvant chemotherapy was given in 13.7%. Acute toxicity (51 patients): grade ≥ 2 dermatitis 27.4%, edema 1.9%, delayed wound healing 3.9%, and pain 16.6%. Late toxicity (49 patients): grade ≥ 2 fibrosis 20.4%, edema 4.1%, and hyperpigmentation in 44.9%. One patient developed a fracture one year after RT. LRFS, OS, and MFS at 48 months were 89.6%, 87.3%, and 77.3%, respectively. Conclusion: Although limited by its retrospective nature, this study suggests that postoperative hypofractionated radiotherapy with advanced technology may be beneficial for soft tissue sarcomas. References: Siegel RL et al. CA CANCER J CLIN. 2020;70:7-30.Beane JD, et al. Ann Surg Oncol. 2014;21:2484-2489SoyferV, et al . Br J Radiol. 2013;86Cammelli S, et al. Eur J Orthp Surg Traumatol. 2021;31a371-1380O Sulivan B, et al. Lancet. 2002;359:2235-2241El Bares, et al. Curr treat options oncol. 2015;16:33National Cancer Institute. CTCAEv5.0.2017 Keywords: Hypofractionated radiotherapy, VMAT, Toxicity
Digital Poster 2474
Postoperative hypofractionated volumetric modulated radiation therapy with integrated simultaneous boost in soft tissue sarcomas Maria Veronica Vera Merino 1 , Guillermo Folonier 1 , Daniela Mariel Angel Schutte 1 , Mario Borra 2 , Daniel Venencia 3 , Maria Jose Almada 3 , Silvia Zunino 1 1 Radioetrapia, Zunino, Córdoba, Argentina. 2 Estadistica, Zunino, Cordoba, Argentina. 3 Fisica, Zunino, Cordoba, Argentina Purpose/Objective: To evaluate acute and late toxicity, local recurrence- free survival (LRFS), overall survival (OS), and metastasis-free survival (MFS). Material/Methods: Between 2017 and 2024, 51 patients with soft tissue sarcoma (STS) were retrospectively analyzed after surgery followed by postoperative hypofractionated IMRT with simultaneous integrated boost (SIB). Acute
Proffered Paper 2564 Prospective phase 2 trial of preoperative intensity
modulated proton radiotherapy with simultaneously integrated boost for retroperitoneal sarcomas
Kevin X Liu 1,2 , Yen-Lin Chen 1 , Beow Y Yeap 3 , Ivy A Petersen 4 , Andrew J Bishop 5 , Sam S Yoon 6 , Alex B Haynes 7 , Christina L Roland 8 , Katherine E Santoro 1 , Madeline G Cavanaugh 1 , Sonia Cohen 9 , Edwin Choy 3 , Gregory M Cote 3 , Gunnlaugur P Nielsen 10 , Dian Wang 11 , John T Mullen 12 , Thomas F DeLaney 13
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