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.