Hemangiosarcoma Hemangiosarcoma (HSA) is a tumor of blood vessels.  Since blood vessels are essential in tumor metastasis, HSA spreads early and aggressively, even when metastatic lesions are not apparent at initial presentation. The most common sites for HSA are the spleen, liver, right atrium (heart), and skin.  The tumor spreads to the lung, most frequently, but can also metastasize to the brain or any other organ. Survival times are usually short, since the tumors cause significant bleeding and spread so early. Surgery is helpful to prevent massive blood loss, but rarely affords a cure. Doxorubicin-based chemotherapy (see protocols) can be helpful, but even with aggressive treatment, survival beyond one year is extremely rare.  Only superficial skin tumors allow long-term survival with surgery alone, although recurrence is likely.  The benefits of radiation therapy are not clear, although in our experience some tumors do respond by shrinking in the short-term.