Pazopanib treatment for primary cardiovascular sarcoma: A retrospective observational study and literature review.

Primary cardiovascular sarcoma (PCS) is a rare, aggressive malignancy with a poor prognosis. The present study describes a single-center experience with pazopanib, an oral multikinase inhibitor, for the outpatient management of unresectable PCS. A retrospective review was conducted of consecutive patients with sarcoma involving the heart and/or pulmonary artery treated with pazopanib at Ehime University Hospital (Toon, Japan) between January 2015 and December 2025. Pazopanib was initiated at 200-400 mg daily and escalated to 600-800 mg according to tolerability. Five patients aged 56-81 years were identified, with angiosarcoma (n=1), intimal sarcoma (n=2) or leiomyosarcoma (n=2). Two patients achieved durable stable disease for >500 days. A case of right atrial angiosarcoma with lung metastasis remained stable for 33 months when treated with 800 mg pazopanib; the patient later died of recurrent cerebral infarction. A case of pulmonary artery intimal sarcoma remained stable for 22 months when treated with 400-600 mg pazopanib; however, treatment was discontinued because of fatigue. Two additional patients stopped treatment because dose escalation led to intolerable toxicities. One patient continued therapy with 800 mg pazopanib as of 8 months, with stable disease, despite requiring a pericardial window for malignant pericardial effusion during treatment. In conclusion, pazopanib can provide meaningful disease control and long-term stabilization for selected patients with unresectable PCS. As treatment-related toxicities frequently limit therapy, individualized dose management and proactive supportive care are essential to maintain treatment continuity and to maximize clinical benefit.