I received a few questions in response to last week’s post on hemangiosarcoma in dogs. I thought I’d address them all together here.

1. Is there any (non-invasive) way to find hemangiosarcoma before there are clinical signs? Is there anything subtle that might be a clue?

Hemangiosarcoma is difficult to diagnose before clinical signs develop. The best, practical option is to bring older dogs in to see the veterinarian twice yearly for wellness checks. A physical exam and routine lab work can point to problems before symptoms arise. An ultrasound is the most sensitive tool for picking up small tumors in the abdomen or heart, but I wouldn’t recommend this as a screening test (i.e., for use on apparently healthy animals). A blood test is available for hemangiosarcoma, but again, it is not recommended for use on dogs with no clinical signs. Rather, it can play a role in differentiating this disease from others that have similar symptoms.

The earliest, most subtle sign associated with hemangiosarcoma in dogs is intermittent lethargy due to small bleeds that stop on their own. Unfortunately, almost all dogs have this symptom at some point in their lives, so it’s not too discriminating.

2. Is the course of hemangiosarcoma different in cats?

I’ve never diagnosed hemangiosarcoma in a cat, so I had to do a little research. Here are some quotes from a fascinating (at least to me) paper that was published in 2007 in the Journal of the American Veterinary Medical Association.

Feline hemangiosarcoma is a rare neoplasm of cats and was diagnosed in only 18 of 3,145 necropsies performed over an 11-year period … as in prior reports, no breed or sex predilection was detected in the present study, and most cats were middle-aged to older animals at the time of initial diagnosis.

Although the specific etiology of hemangiosarcoma is not well understood, the prevalence of cutaneous lesions on the head (including conjunctiva), muzzle, and ears make exposure to UV radiation and local pigmentation characteristics potential predisposing factors.

Surgical excision was the primary treatment modality used for cutaneous and subcutaneous hemangiosarcoma in the present study…

Results of the present study indicated that in cats cutaneous (involving the skin) and subcutaneous (involving the tissues under the skin) hemangiosarcoma may occur more commonly than visceral (involving a large organ in the abdomen or chest) hemangiosarcoma. Similar to canine hemangiosarcomas, feline subcutaneous hemangiosarcomas are more likely to be incompletely excised, recur locally, and have more aggressive biological behavior than cutaneous masses. Thus, subcutaneous hemangiosarcoma may warrant more aggressive surgical excision, multimodality therapy (a combination of surgery, chemotherapy, and/or radiation), and a more guarded prognosis … as in dogs, visceral hemangiosarcoma in cats warrants a poor to grave prognosis despite therapeutic interventions. As additional cats with hemangiosarcoma are treated with adjunctive therapy, more detailed information regarding the best treatment options and response to specific therapy will hopefully become available.

3. Is this an inherited disease?

We don’t have any specific evidence that heredity plays a role in most cases of canine hemangiosarcoma. However, the fact that the disease has a higher incidence in some breeds (e.g., boxers, doberman pinschers, German shepherd dogs, golden retrievers, Labrador retrievers, pointers, and schnauzers) indicates that genetics could be one of several factors that combine to determine which dogs are affected and which remain free of this devastating disease.

Dr. Jennifer Coates

Image: Bluey and Turtke at the Vet by Adria Richards / via Shutterstock