Https://doi.org/10.18632/oncotarget.28654 Marta Arregui, Antonio Calles, María del Mar Galera, Ana Gutiérrez, Carlos López-Jiménez, Carolina Agra, Adriana Fernández, Natalia Gutiérrez, María de Toro,...

Background/Objectives: Primary cardiac sarcomas are rare and aggressive tumors. Management is often guided by evidence from other sarcoma types due to limited disease-specific data. This study aimed to analyze the clinical characteristics, pathology, treatment, and outcomes of primary cardiac sarcomas at a national referral center in Spain. Methods: We conducted a retrospective, observational, single-center study from February 2017 to December 2024. Patient data were collected from medical records, and a descriptive analysis was performed. Results: Twelve patients were identified (58% female; median age 43 years, range 13–76). Dyspnea was the most common symptom (8/12, 67%), and the right atrium was the most frequent tumor site (6/12, 50%). Angiosarcoma was the predominant histologic subtype (6/12, 50%). Seven patients had localized disease at diagnosis. Surgery was performed in six patients, with complete (R0) resection in two. Two patients received adjuvant chemotherapy, one underwent cardiac transplantation, and one received sequential chemo- and radiotherapy. All patients experienced tumor recurrence, with a median recurrence-free survival of 5 months (95% CI, 1.5–8.6). Median overall survival for localized disease was 22 months (95% CI, 16–28). Five patients were metastatic at diagnosis, and 11 of 12 developed metastases. Median progression-free survival for first-line therapy was 5.9 months (95% CI, 1.8–9.9), and median overall survival for advanced disease was 12 months (95% CI, 10–13.6). Conclusions: Complete surgical resection was rarely achieved, and recurrence was universal. Outcomes remained poor even for localized disease, highlighting the limited efficacy of current therapies and the need for improved multimodal treatment strategies.

Supplementary Table S3. Univariate Analysis of Different Potential Prognostic Factors on PFS and OS.

Supplementary Table S1. Representativeness of Study Participants

Supplementary Figure S2. Variation of HMGB1 protein levels between samples collected after treatment (week 6) and before treatment (baseline).