Copenhagen, Denmark
Onsite/Online

ESTRO 2022

Session Item

Sarcoma/Skin cancer/malignant melanoma
6022
Poster (digital)
Clinical
Preoperative moderate hypofractionated radiation therapy for soft-tissue sarcomas: response analysis
Xin Chen-Zhao, Spain
PO-1428

Abstract

Preoperative moderate hypofractionated radiation therapy for soft-tissue sarcomas: response analysis
Authors:

Xin Chen-Zhao1, Ángel Montero2, Jorge de las Heras3, Beatriz Álvarez1, Irene Barrientos3, Alejandro Prado4, Raquel Ciérvide1, Mercedes López1, Mariola García-Aranda1, Eduardo Ortiz3, Maite Gutiérrez5, Emilio Sánchez6, Ovidio Hernando7, Miguel Ángel De la Casa4, Jeannette Valero1, Rosa Alonso1, Pedro Fernández-Letón8, Carmen Rubio9

1HM Hospitales, Radiation Oncology, Madrid, Spain; 2HM Hospitales, Radiation Onccology, Madrid, Spain; 3HM Hospitales, Orthopedic Surgery, Madrid, Spain; 4HM Hospitales, Medical Physics, Madrid, Spain; 5HM Hospitales , Orthopedic Surgery, Madrid, Spain; 6HM Hospitales, Medical Physic, Madrid, Spain; 7HM Hospitales, Radiation Oncology, Madrid, Spain; 8HM Hospitales, Medical Physics, Madrid, Spain; 9HM Hospitales, Radiation Oncology, Madrid, Spain

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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.

Material 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.


Results

Eight patients (57%) reached mPR, being fully complete in 4 of them. On univariate analysis, mPR rates were higher for female patients, older patients, thigh location, smaller tumor size (<14cm), low grade tumors and liposarcoma histology although these differences were not statistically significant, probably due to low number of analyzed patients. However, addition of preoperative chemotherapy to radiation treatment associated higher probability of mPR. Complete analysis of relationship between mPR and clinical and epidemiological variables is detailed in table 2.

With a median follow-up of 13 months (7 – 19), 12 patients are alive, 2 patients died from distant tumor progression and no patient suffered from local relapse. Median overall survival (OS), local progression free survival (L-PFS) and distant progression free survival (D-PFS) times are not achieved. Actuarial 2-year OS and D-PFS are 79.5%, and 72.4% respectively.

mPR is related to a statistically significant better OS (p=0.032) and better D-PFS (p=0.016). The absence of mPR was associated with higher risk of developing distant metastases (100% vs 36.4%, p = 0.051).

Treatment tolerance: 5 patients (35.7%) presented grade 1-2 acute skin toxicity after radiation treatment. Post-surgical complications: 5 patients (35.7%) had post-surgical seroma, 1 patient (7.1%) had neuropathic pain and 8 patients (57.1%) had wound complications. Five patients did not experience any degree of radiation or postsurgical side effects.

 

Conclusion

preoperative hypofractionated radiotherapy in 3-weeks is feasible, well tolerated and associates acceptable pathologic response rates. Achievement of mPR is related to better distant-metastases and overall survival. Addition of preoperative chemotherapy to radiation therapy could increase pathologic response rates and deserves further study searching for radio-enhancement synergies