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What Is the Prognostic Value of the Pathologic Response after Neoadjuvant Radiotherapy in Soft Tissue Sarcoma? An Institutional Study Using the EORTC–STBSG Response Score
by
, ,
Anastasia Stergioula
1,2,3,*
,
Theodoros Kormas
4, 
Stefania Kokkali
5,
Nikolaos Memos
6,
Evaggelos Pantelis
3,7,
Despina Pouloudi
1 and
Georgios Agrogiannis
1 1
1st Department of Pathology, Medical School, National and Kapodistrian University of Athens, 157 72 Athens, Greece
2
Center of Radiotherapy, IASO General Hospital, 151 23 Athens, Greece
3
Radiotherapy Department, Iatropolis Clinic, 115 21 Athens, Greece
4
Department of Orthopedic Surgery, Agios Savvas Anticancer Hospital, 115 22 Athens, Greece
5
Oncology Unit, Department of Internal Medicine, Hippocratio General Hospital, National and Kapodistrian University of Athens, 157 72 Athens, Greece
6
2nd Department of Surgery, Medical School, Aretaieion Hospital, National and Kapodistrian University of Athens, 157 72 Athens, Greece
7
Medical Physics Laboratory, Medical School, National and Kapodistrian University of Athens, 157 72 Athens, Greece
*
Author to whom correspondence should be addressed.
Cancers 2024, 16(20), 3449; https://doi.org/10.3390/cancers16203449 (registering DOI)
Submission received: 5 September 2024
/
Revised: 9 October 2024
/
Accepted: 10 October 2024
/
Published: 11 October 2024
(This article belongs to the Special Issue Clinical and Surgical Outcomes in the Management of Extremity Soft Tissue Sarcomas)
Simple Summary
The pathologic response after neoadjuvant radiotherapy in soft tissue sarcoma of the extremities and trunk was evaluated using the EORTC-STBSG response score. The median percentages of viable cells, necrosis and fibrosis/hyalinization were 20%, 11% and 40%, respectively. A pathologic complete response, defined as ≤5% viable tumor cells, was achieved in 25% of cases. Local recurrence occurred in 33% of cases, with a significantly higher rate of 64% after R1 excision compared to 22% after R0 resection. Distant metastases were observed in 42% of patients, primarily in the lungs. The local recurrence free survival, distant metastasis free survival and overall survival rates were 65%, 54%, and 67% at 3-years, respectively. A correlation between tumor histological subtype, size and grade with outcome was observed. While the EORTC-STBSG response score did not correlate with clinical outcomes, resection specimens with ≤5% viable tumor cells were linked to improved outcomes.
Abstract
Background/Objectives: The relationship between pathologic findings in soft tissue sarcoma (STS) after neoadjuvant treatment and oncological outcomes remains uncertain due to varying evaluation methods and cut-off values. This study aims to assess pathologic findings after neoadjuvant radiotherapy in STS using the EORTC-STBSG response score and evaluate its prognostic value. Methods: Clinical and outcome data from 44 patients were reviewed. Resected specimens were re-evaluated to measure viable cells, necrosis, fibrosis, and hyalinization. Local recurrence-free survival (LRFS), distant metastasis-free survival (DMFS), and overall survival (OS) were analyzed using Kaplan–Meier survival analysis. Cox proportional hazards regression was used for univariate and multivariate analyses to correlate outcomes with pathologic response. Results: The median percentages of viable cells, necrosis, and fibrosis/hyalinization were 20%, 11%, and 40%, respectively. A pathologic complete response (pCR), defined as ≤5% viable cells, was achieved in 25% of cases. Local recurrence occurred in 33% of cases, with a significantly higher rate of 64% after R1 resection compared to 22% after R0 resection. Distant metastases were observed in 42% of patients, primarily in the lungs. The 3-year rates for LRFS, DMFS, and OS were 65%, 54%, and 67%, respectively. A correlation between outcomes and tumor size, grade and histological subtype was observed. Classifying pathologic response by the EORTC-STBSG score failed to show an association with outcomes. Patients achieving pCR showed lower risk of LR and improved OS. Conclusions: While the EORTC-STBSG score did not show a prognostic value, resection specimens with ≤5% viable cells were linked to improved LRFS and OS.
