ESTRO 2022 - Abstract Book

S1210

Abstract book

ESTRO 2022

Conclusion In our experience a high dose IMRT irradiation following CRYO, IRE or HIFU is well tolerated with moderate acute and late toxicity.

Poster (digital): Sarcoma/Skin cancer/malignant melanoma

PO-1427 Salvage Irradiation and Repeat Wide Resection for Unplanned Surgery of Soft Tissue Sarcoma

V. Soyfer 1 , R. Kollender 1 , A. Sternheim 2 , Y. Gortzak 2 , S. Dadia 2 , A. Doron 3 , I. Novikov 4 , Y. Kollender 2 , O. Merimsky 3

1 Tel Aviv Medical Center, Radiation Oncology, Tel Aviv, Israel; 2 Tel Aviv Medical Center, Orthopedic Oncology, Tel Aviv, Israel; 3 Tel Aviv Medical Center, Oncology, Tel Aviv, Israel; 4 Gertner Institute, Statistics, Tel Aviv, Israel Purpose or Objective The main goal of the treatment of soft tissue sarcomas is achieving wide negative margins to improve local control and prevent a recurrence. The role of radiation therapy (RT) is well-established in sarcomas of the extremities, however, published data on its role in unplanned “Oops” operations are scarce. We report on the effect of RT followed by resection as salvage treatment after unplanned surgery. Materials and Methods Sixty-five patients who had undergone an unplanned resection of a postoperatively diagnosed soft tissue sarcoma were treated with RT and/or surgery and retrospectively evaluated for disease progression. Treatment started with RT in 49 (75.4%) cases, including 8 cases of no further surgery. A repeat wide resection was performed directly after the initial surgery in 16 patients followed by RT in 15 of them. Results The disease recurred in 7 out of 49 (14.3%) patients who received RT first and in 9 out of 16 (56.25%) who underwent reoperation before RT ( P = .001). Disease-free progression was higher in cases of low-grade malignancy ( P = .049). The clinical diagnosis of lipoma was associated with better outcome than non-lipoma ( P = .034). The presence of residual tumor at reoperation did not impact disease control. Patient age, time between symptom onset and diagnosis, hospital level of initial diagnosis (tertiary versus non-tertiary), anatomic site, tumor size, and margin status at the initial excisional biopsy were not significantly correlated with outcome. Conclusion Initiating treatment with RT followed by resection as salvage treatment after an unplanned resection of soft tissue sarcoma improves disease control. X. Chen-Zhao 1 , Á. Montero 2 , J. de las Heras 3 , B. Álvarez 1 , I. Barrientos 3 , A. Prado 4 , R. Ciérvide 1 , M. López 1 , M. García- Aranda 1 , E. Ortiz 3 , M. Gutiérrez 5 , E. Sánchez 6 , O. Hernando 7 , M.Á. De la Casa 4 , J. Valero 1 , R. Alonso 1 , P. Fernández-Letón 8 , C. Rubio 9 1 HM Hospitales, Radiation Oncology, Madrid, Spain; 2 HM Hospitales, Radiation Onccology, Madrid, Spain; 3 HM Hospitales, Orthopedic Surgery, Madrid, Spain; 4 HM Hospitales, Medical Physics, Madrid, Spain; 5 HM Hospitales , Orthopedic Surgery, Madrid, Spain; 6 HM Hospitales, Medical Physic, Madrid, Spain; 7 HM Hospitales, Radiation Oncology, Madrid, Spain; 8 HM Hospitales, Medical Physics, Madrid, Spain; 9 HM Hospitales, Radiation Oncology, Madrid, Spain Purpose or Objective Preoperative radiotherapy +/- chemotherapy is a standard approach for conservative treatment of soft-tissue sarcoma (STS). We report our experience by using a moderate hypofractionated radiation treatment and its impact on pathologic response. Materials and Methods 14 consecutive patients with localized STS sarcoma were prospectively included in this analysis from 2015 to 2021. All patients underwent preoperative IMRT/VMAT up to a total median dose of 52.5 Gy (50-52.5Gy) in 15 fractions of 3.2-3.5Gy followed by perioperative HDR brachytherapy 16.5 Gy in 3 fractions of 5.5 Gy BID. Complete details of patients’ characteristics are detailed in Table 1. Pathologic response was considered as major response (mPR) when less than 10% of viable tumor was found. Statistical analysis by using SPSS v20 comprised Person’s Chi-square to determine significant difference between analyzed variables and the Kaplan-Meier method for survival analysis. PO-1428 Preoperative moderate hypofractionated radiation therapy for soft-tissue sarcomas: response analysis