Clinical Characteristics, Patterns of Care, and Treatment Outcomes of Radiation-Associated Sarcomas.

Simple Summary: Radiation-associated sarcomas pose a significant clinical challenge due to their complexity, aggressiveness, and poor prognosis. Our retrospective study is one of the largest descriptions of radiation-associated sarcomas, aiming to shed light on their clinicopathologic characteristics and highlight treatment approaches. Our research found a significant association between high radiation-associated sarcoma histologic grade and inferior clinical outcomes. We also found that localized radiation-associated sarcoma patients who underwent margin-negative resections lived significantly longer than their counterparts. Our analysis thus confirms the paramount role of tumor grade and the central importance of margin-negative oncologic resection in determining clinical outcomes for radiation-associated sarcomas. Radiation-associated sarcomas (RASs) are rare tumors with limited contemporary data to inform prognostication and management. We sought to identify the clinical presentation, patterns of care, and prognostic factors of RASs. RAS patients treated at a single institution from 2015 to 2021 were retrospectively reviewed for clinicopathologic variables, treatment strategies, and outcomes. Thirty-eight patients were identified with a median follow-up of 30.5 months. The median age at RAS diagnosis was 68.4 years (27.9–85.4), with a median latency from index radiotherapy (RT) of 9.1 years (3.7–46.3). RAS histologies included angiosarcoma (26%), undifferentiated pleomorphic sarcoma (21%), and osteosarcoma (18%). Most were high-grade (76%). Genomic profiling revealed low tumor mutational burden, frequent inactivating TP53 mutations (44%), CDKN2A deletions (26%), and MYC amplifications (22%), particularly in breast angiosarcomas. Of 38 patients, 33 presented with localized disease, 26 of whom were treated with curative intent. Overall, the median progression-free survival (PFS) was 9.5 months (1.4–34.7), and the overall survival (OS) was 11.1 months (0.6–31.6). Patients with localized vs. metastatic RASs had a longer PFS (HR, 3.0 [1.1–8.5]; p = 0.03) and OS (HR, 3.0 [1.04–8.68]; p = 0.03). Among localized RAS patients, high grade was associated with shorter OS (HR, 4.6 [1.04–20.30]; p = 0.03) and resection with longer OS (mean 58.8 vs. 6.1 months, HR, 0.1 [0.03–0.28]; p < 0.001). Among patients undergoing resection, negative margins were associated with improved OS (mean 71.0 vs. 15.5 months, HR, 5.1 [1.4–18.2]; p = 0.006). Patients with localized disease, particularly those undergoing R0 resection, demonstrated significantly better outcomes. Novel strategies are urgently needed to improve treatment outcomes in this challenging group of diseases. [ABSTRACT FROM AUTHOR]