Pulmonary Artery Sarcoma Study: A Multi-Center ESTS Working Group Evaluating Diagnosis, Treatment, and Outcomes

Objectives: Pulmonary artery sarcoma (PAS) is a rare and aggressive malignancy often mimicking pulmonary embolism, leading to diagnostic delays and poor outcomes. This study aims to describe the clinical characteristics, diagnostic pathways, treatment modalities, and outcomes of PAS patients of a multicentre cohort. Methods: This retrospective cohort study included patients from seven institutions between 1994 and 2024. Clinical, radiological, histological, and treatment data were collected via a standardized REDCap-based platform. All patients underwent either multimodal treatment or single therapy approach, including systemic therapy, surgery and/or radiotherapy. Kaplan-Meier survival analysis and log-rank testing were performed to assess overall survival (OS) and progression-free survival (PFS). Results: 84 patients from seven international centers were analyzed. The mean age was 54.4 years, and 43.8% of patients were female. The most common presenting symptoms were dyspnoea (81.2%) and chest pain (50.0%). Pulmonary embolism was the most frequent initial misdiagnosis (49.1%). Histologically, PAS was diagnosed in 46 cases.Tumors were bilateral in 58.1% of patients with surgery only. Most commonly endarterectomy was performed in 59.5%.After a median follow-up time of 39 months, 19 were excluded as they either had no treatment information or received monotherapy only. Additionally, 11 patients were excluded due to missing date of diagnosis, and 17 due to missing overall follow-up date. There was moderate evidence for OS to differ between treatment groups (75th quantile: 34 multimodal (95%-CI: 26 to not reached) vs 11 surgery only (95%-CI: 7 to 21) months; log-rank p = 0.022). There was no evidence for PFS to differ between treatment groups (median 19 multimodal (95% CI: 14 to 39) vs 16 surgery only (95% CI: 11 to 21) months; log-rank p = 0.69). Conclusions: This study represents the largest reported PAS cohort to date and underscores the diagnostic challenges and poor prognosis associated with this disease. Our findings offer evidence that multimodal treatment provides significant prognostic benefits. However, further prospective studies are warranted to establish standardized diagnostic and therapeutic protocols.