Blood Tumors in Dogs

Canine hemangiosarcoma (HSA) is a common, incurable blood tumor. It is a highly malignant, soft-tissue cancer of the cells that normally form blood vessels. According to the National Canine Cancer Foundation (NCCF) "Based on the current estimates of the lifetime risk of cancer in dogs and the prevalence of hemangiosarcoma, we predict that of the 73.9 million pet dogs living in the United States today, as many as two million may get this cancer and die from it."

  1. Types

    • HSA is broken down into three types: dermal, hypodermal and visceral. Canine Cancer Awareness.org states that the visceral (splenic or cardiac) form is most common and "accounts for two percent of all reported malignancies and up to five percent of all non-cutaneous tumors in dogs." The spleen and the right atrium of the heart are the most common locations. Dermal (skin) HSA appears as a dark to purple, raised skin lesion on non-haired areas. And hypodermal (under the skin) HSA can occur anywhere on the body.

    Signs

    • Watch for loss of stamina in your dog, which is an early warning sign of cancer

      The NCCF lists the following signs of HSA: abnormal swellings that persist or continue to grow, sores that do not heal, weight loss, loss of appetite, bleeding or discharge from any body opening, offensive odor, difficulty eating or swallowing, hesitation to exercise or loss of stamina, persistent lameness or stiffness, and difficulty breathing, urinating or defecating. Although the above are somewhat generic symptoms, HSA is a "silent" killer difficult to detect until in an advanced stage. Therefore, monitoring for early warning signs is critical.

    Diagnosis

    • Veterinarians will confirm diagnosis through physical exam and laboratory tests. Very large tumors are easy to spot during physical exam. However, hundreds of small tumors may spread throughout the body, thus making them difficult to find without X-rays and lab work. As a result, vets normally run several tests to obtain a diagnosis and prepare for surgery. These include blood tests, urinalysis, clotting profile, exam of fluid taken from the abdomen, as well as chest and abdominal X-rays.

    Treatment

    • Surgery is the primary method of treatment for HSA, which involves removal of the spleen. Although patients are stabilized prior to surgery, complications can present during surgery, such as hemorrhage, cardiac arrhythmias and pancreatitis. According to Canine Cancer Awareness.org, "Recommended chemotherapy for hemangiosarcoma is single-agent doxorubicin, intravenously given every three weeks." A total of four to six doses are recommended via the use of an indwelling catheter. Cardiotoxicity and other problems may result from chemotherapy.

    Prognosis

    • The American College of Veterinary Surgeons (ACVS) comments that "tumor spread (metastasis) is present in more than 80 percent of dogs" at their initial presentation. Mean survival times with surgery alone range from 19 to 86 days. The ACVS notes, "One-year survival is less than 10 percent. Ultimately dogs die of metastatic disease. Chemotherapy may increase survival times up to 141 to 179 days, but owners must weigh the outcome against the risk of side effects." No known prevention exists for this disease, although clinical trials are ongoing.