Moderate hypofractionated radiation therapy and pathologic response for soft tissue sarcomas (STS) of limbs and trunk: experience from a tertiary cancer center

• Angel Montero ^[1] ; Xin Chen-Zhao ^[1] ; Raquel Ciérvide ^[1] ; Beatriz Álvarez ^[1] ; Alejandro Prado ^[2] ; Mercedes López ^[1] ; Emilio Sánchez ^[1] ; Ovidio Hernando ^[1] ; Miguel Angel de la Casa ^[2] ; Mariola García-Aranda ^[1] ; Jeannette Valero ^[1] ; Rosa Alonso ^[1] ; Pedro Fernández-Letón ^[2] ; Carmen Rubio ^[1]
  1. [1] Department of Radiation Oncology, Centro Integral Oncológico Clara Campal (C.I.O.C.C.), HM Hospitales, Madrid
  2. [2] Department of Medical Physics, Centro Integral Oncológico Clara Campal (C.I.O.C.C.), HM Hospitales, Madrid
• Localización: Clinical & translational oncology, ISSN 1699-048X, Vol. 26, Nº. 1, 2024, págs. 204-213
• Idioma: inglés
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• Resumen

  • Background Preoperative radiation therapy following by limb-sparing or conservative surgery is a standard approach for limb and trunk STS. Data supporting hypofractionated radiotherapy schedules are scarce albeit biological sensitivity of STS to radiation would justify it. We sought to evaluate the impact of moderate hypofractionation on pathologic response and its influence on oncologic outcomes.

    Material and methods From October 2018 to January 2023, 18 patients with limb or trunk STS underwent preoperative radiotherapy at a median dose of 52.5 Gy (range 49.5–60 Gy) in 15 fractions of 3.5 Gy (3.3-4 Gy) with or without neoadjuvant chemotherapy. A favorable pathologic response (fPR) was considered as ≥ 90% tumor necrosis on specimen examination.

    Results All patients completed planned preoperative radiotherapy. Eleven patients (61.1%) achieved a fPR, and 7 patients (36.8%) a complete pathologic response with total disappearance of tumor cells. Nine patients (47%) developed grade 1–2 acute skin toxicity, and 7 patients (38.8%) had wound complications on follow-up. With a median follow-up of 14 months (range 1–40), no cases of local relapse were observed, and actuarial 3-year overall survival (OS) and distant metastases-free survival (DMFS) are 87% and 76.4%, respectively. In the univariate analysis, the presence of a favorable pathologic response (fPR) was associated with improved 3-year OS (100% vs. 56.03%, p = 0.058) and 3-year DMFS (86.91% vs. 31.46%, p = 0.002). Moreover, both complete or partial RECIST response and radiological stabilization of the tumor lesion showed a significant association with higher rates of 3-year distant metastasis-free survival (DMFS) (83% vs. 83% vs. 56%, p < 0.001) and 3-year overall survival (OS) (100% vs. 80% vs. 0, p = 0.002).

    Conclusions Preoperative moderate hypofractionated radiation treatment for STS is feasible and well tolerated and associates encouraging rates of pathologic response that could have a favorable impact on final outcomes.