Every pet parent dreads “The Big C” for their fur babies. Cancer strikes fear in the hearts and minds of pet-owning families. As a board-certified critical care specialist, one of the most common cancers I diagnose and treat is called hemangiosarcoma. I wanted to dedicate some time explaining this cancer, as some encouraging news about a novel treatment was recently released. Happy reading!

Hemangiosarcoma – What is it?

Hemangiosarcoma is a cancer of endothelial cells, the cells that line blood vessels. We don’t currently know what causes some dogs to develop this cancer. Multiple studies have tried to shed more light on this topic. Risk factors include:

  • Heritability – certain breeds are over-represented for developing this cancer
  • Ultraviolet light exposure – long-term exposure in lightly pigmented short-haired breeds increases risk
  • Abnormal gene expression
  • Abnormal development of new blood vessels

Hemangiosarcoma usually occurs in middle-aged and geriatric dogs. Certain breeds are over-represented, including:

  • Golden retrievers
  • German shepherds
  • Labrador retrievers
  • English setters
  • Boxers
  • Doberman pinschers

Hemangiosarcoma can develop anywhere in the body where there are blood vessels. This cancer is often classified as follows:

  • Dermal – The skin form typically appears as red or black skin growths. These masses can become ulcerated and bleed. Approximately 33% of these tumors will spread to internal organs, so early identification and removal are key.

Classic appearance of dermal hemangiosarcoma in a dog. Photo courtesy of Joel Mills.