Canine hemangiosarcoma is an aggressive cancer that originates from the cells lining blood vessels. This malignancy can develop in any area of the dog’s body. The disease often progresses rapidly, with subtle signs in its early stages.
Understanding Canine Hemangiosarcoma
Canine hemangiosarcoma is a malignant tumor derived from endothelial cells, which form the inner lining of blood vessels throughout the body. Because these cells are ubiquitous, the cancer can arise almost anywhere, though it most commonly affects the spleen, heart, liver, and skin. These tumors are highly vascular and fragile, making them prone to rupture and subsequent internal bleeding.
The aggressive nature of hemangiosarcoma means it can spread quickly to other organs, such as the lungs and other abdominal structures, even before a diagnosis is made. While the exact cause remains unknown, genetic predisposition plays a role. Breeds frequently affected include Golden Retrievers, German Shepherds, Labrador Retrievers, Boxers, and Portuguese Water Dogs. It primarily affects middle-aged to older dogs, though younger animals can also be affected.
Recognizing the Signs
Recognizing the signs of canine hemangiosarcoma can be challenging, as initial symptoms are often vague or non-specific. Dogs might exhibit intermittent lethargy, weakness, or a decreased appetite. These subtle changes can make early detection difficult, as they may resolve temporarily, giving a false sense of improvement.
More concerning signs often emerge when a tumor ruptures, leading to internal bleeding. Such events can cause sudden and severe symptoms, including collapse or profound weakness. Other indications of internal hemorrhage include pale gums, a distended abdomen, rapid or labored breathing, and vomiting. Any sudden onset of these severe signs warrants immediate veterinary attention, as they indicate a life-threatening emergency.
Diagnosis and Treatment
Diagnosing hemangiosarcoma often begins with a thorough physical examination, where a veterinarian might detect an abdominal mass or note pale gums. Initial diagnostic steps involve imaging tests such as abdominal ultrasound and X-rays of the chest and lungs to identify masses and assess for spread. An echocardiogram, an ultrasound of the heart, may also be performed to check for tumors in the heart, particularly the right atrium.
Blood tests, including a complete blood count and chemistry panel, help evaluate the dog’s overall health and can reveal anemia due to blood loss. A definitive diagnosis of hemangiosarcoma requires a biopsy, where a tissue sample is taken from the suspected tumor and examined by a pathologist. Due to the fragile nature of these tumors, fine needle aspirates may not yield a conclusive diagnosis, as they often collect only blood rather than tumor cells.
Treatment for hemangiosarcoma involves a combination of surgery and chemotherapy. Surgical removal of the tumor, such as a splenectomy for splenic tumors, aims to remove the primary mass and address any active bleeding. This procedure can improve a dog’s quality of life in the short term and is often followed by chemotherapy to target any remaining cancer cells and delay the progression of metastatic disease. While surgery alone offers a short survival time (19-86 days), combining it with chemotherapy can extend the median survival to four to six months, or up to nine months. For tumors in locations where surgery is not feasible, such as the heart, chemotherapy may be the primary treatment option, and radiation therapy might be considered for incompletely excised skin tumors or as palliative care.
Prognosis and Management
The prognosis for dogs diagnosed with hemangiosarcoma is often guarded due to its aggressive nature and high propensity for metastasis. Microscopic spread of cancer cells is common even before a definitive diagnosis, with up to 80% of dogs having metastases at the time of diagnosis. Despite aggressive treatment, the one-year survival rate for splenic hemangiosarcoma remains low, less than 10-15%.
Median survival times vary depending on the tumor’s location and whether treatment is pursued. For splenic hemangiosarcoma treated with surgery alone, median survival can range from one to three months. This can extend to four to six months with the addition of chemotherapy protocols, often involving drugs like doxorubicin. Palliative care focuses on managing symptoms and maintaining comfort, which can include pain medication, nutritional support, and monitoring for signs of distress. Discussions with a veterinarian about quality of life and potential end-of-life care are important to ensure the dog’s comfort throughout the disease progression.