Main Session
Sep 27
PQA 02 - Pediatric Cancer, Sarcoma and Cutaneous Tumors, Medical Education & Professional Development, and Health Services Research

2320 - Response Evaluation and Prognostic Factors in Soft Tissue Sarcoma Patients Treated with Preoperative Hypofractionated Radiotherapy

04:00pm - 05:00pm ET
Poster Hall - Exhibit Hall A
Screen: 16
POSTER

Presenter(s)

Ece Ercan, MD - Marmara Universitesi Pendik Egitim ve Arastirma Hastanesi, Istanbul, Istanbul

E. Ercan Jr1, Z. Ozgen1, E. Cesmecioglu Karavin2, O. Bugdayci3, H. K. Turkoz2, E. Sirin4, and O. Sofulu4; 1Department of Radiation Oncology, Marmara University School of Medicine, Istanbul, Turkey, 2Department of Medical Pathology, Marmara University School of Medicine, Istanbul, Turkey, 3Department of Radiology, Marmara University School of Medicine, Istanbul, Turkey, 4Department of Orthopedics and Traumatology, Marmara University School of Medicine, Istanbul, Turkey

Purpose/Objective(s):

Limb-sparing surgery with radiotherapy (RT) is the standard treatment approach in selected patients with soft tissue sarcomas (STS). The aim of this study was to evaluate the clinical and pathological outcomes and the association of HIF-1a and p53 expression with treatment response in STS patients treated with hypofractionated preoperative RT.

Materials/Methods:

This retrospective study included 25 patients diagnosed with STS who received preoperative hypofractionated RT (42.75 Gy/15 fractions). HIF-1a and p53 expression were assessed using immunohistochemical methods in pretreatment biopsy specimens. Pathological response was determined based on the total proportion of necrosis and fibrosis identified in the surgical resection specimens, with =90% necrosis/fibrosis defined as pCR90. Radiological response was evaluated according to RECIST 1.1. Major wound complications were recorded using the NCIC-SR2 trial criteria. Functional status and quality of life were assessed before and after RT using the MSTS and the EORTC QLQ-C30.

Results:

Mean age of the patients was 54.8 ± 16.7 years; 80% of tumors were located in the lower extremity, and 76% were high-grade. pCR90 was achieved in nine patients (36%). No significant association was observed between pCR90 and tumor size, tumor grade, HIF-1a or p53 expression, or radiological response. The median follow-up time was 16 months. One- and two-year overall survival rates were 87.8% and 81.5%; disease-free survival rates were 87.5% and 68.7%, respectively. The rate of major wound complications was 33.3%, with no significant risk factors. Post-RT MSTS scores improved significantly in patients with lower-extremity tumors.

Conclusion: Hypofractionated preoperative RT is a feasible treatment approach with an acceptable toxicity profile in STS, and further studies are needed to clarify the role of biomarkers such as HIF-1a and p53 in treatment response.