Hemangiosarcoma (HSA) is one of two inherited cancers in the Australian
Shepherd. (The other is lymphoma.) HSA, an aggressive cancer of the vascular tissue
(blood vessels) is very common in the breed. It can form almost anywhere but tumors
most frequently initiate in the spleen, heart, and occasionally the skin. Because it
begins in a blood vessel it spreads readily, often to the lungs or liver.
Prognosis for dogs with HSA is a very poor, with most surviving only a few weeks
or months after diagnosis. Sometimes the first indication that the dog is ill is a sudden
catastrophic collapse. If any Aussie over 4 years that dies suddenly from no apparent
cause may have died from HSA; if at all possible a necropsy should be done to verify
whether or not HSA was the cause. The skin form, if caught early enough, may be
cured by tumor removal. It is also the easiest type to treat with the longest survival
First-step relatives of affected dogs (parents, full and half siblings, and offspring)
should be bred only to mates with pedigrees as clear of HSA as possible and who have
no affected close relatives. If semen has been stored from a male that developed HSA
it should be discarded.