Hemangiosarcoma and Your Dog


If you are reading this, it's probably not for fun.  But here's something you should know -- You are NOT alone.  I've been helping pets with hemangiosarcoma.. and their parents... for over 30 years, and I am happy to help you, too.

Here's what you need to know.



Hemangiosarcomas, or HSA, are a tumor derived from the cells that line blood vessels.  Because the spleen acts as a filter for the blood, it has vast numbers of blood vessels and this is why the spleen is the most commonly affected organ for HSA.   Another common spot is the heart, for obvious reasons, but HSA can occur anywhere.  There is a benign version of blood vessel walls called a hemangioma, although they are pretty uncommon.



HSA start as microscopic nodules growing within the wall of a blood vessel.  As they grow, they expand in all directions, pushing normal tissue out of the way and damaging it.  This tumor growth is nourished by the blood within the affected blood vessel itself, and so they can grow very quickly. 

Because blood is literally flowing through the tumor,  it is very easy for tumor cells to dislodge, float downstream in the blood vessels, and settle out somewhere else.  This is why the odds of metastasis, or distant spread, are so high (more on that below). 

You can think of the normal spleen as a fine sponge shaped like a large New York steak.  As the tumor grows, it stretches and enlarges the spleen.  This enlargement tugs on the spleen’s attachment, called a mesentery, and creates abdominal pain.

If the tumor breaks through the outer lining of the spleen, it can cause massive bleeding which will generally result in death within just a few minutes.



Traditionally, most HSA are diagnosed via abdominal imaging of either ultrasound or x-rays, or as an incidental finding during surgery.  Anemia on routine blood tests can also be an indicator.

However, now there are "Early Cancer Detection" blood tests that can reliably detect HSA even before they are visible on imaging.  This is a HUGE improvement in diagnosing HSA, as it can potentially allow tumor removal prior to spread.   The two test companies are NuQ and OncoK9, and I can help you with the testing procedure. 



The general rule of thumb is that if you find a splenic mass in a large breed dog…

     -80% of the time it is a malignancy, almost always an HSA, and…

     -80% of the time that tumor has already spread to distant sites, generally in the abdomen.

Should that stop you from surgery?  Absolutely not, because…

     -you still have a 20% chance of benign tumor or hematoma; and

     -as noted above, if that tumor/hematoma ruptures, a pet will die within minutes.

The diagnosis of malignancy can ONLY be made by biopsy of the mass.  No exceptions.



When you and your vet identify a splenic mass, the best course of action is IMMEDIATE surgical spleen removal.  The longer you delay, the higher the odds of both metastasis and tumor rupture.

Pre-operative blood tests should always be done, because you can see blood leakage into the belly which can create anemia.  If this is the case, your pet may need a transfusion either before or during the surgery.



Traditionally, most HSA patients only live for 2-3 months post diagnosis.  There are some things that we can do to improve our odds, and I cover them below.

ABOVE ALL ELSE,  LOVE YOUR PET.  They don’t know that they are sick, they just know that their belly hurts after the surgery.  Pets are VERY INTUITIVE, and will pick up on your emotions.  So spoil them, laugh with them, and keep their normal routine…. And cry in private.

 AND FIND A SPECIALIST.  This is absolutely a time to involve a veterinary oncologist, or cancer specialist.  Here is a link to search for the oncologist nearest you.



1)  TRADITIONAL CHEMOTHERAPY:   Combining surgery with chemotherapy is currently thought to give longest survival.  The drug of choice is doxorubicin, which is generally given as an IV injection by your vet every 3 weeks for 5-6 cycles.  Here is a good study that shows significant increases in survival time with this protocol, as opposed to just surgery alone.  However, this survival is generally limited to just a few extra months.

2) RAPAMYCIN: Rapamycin is a very safe drug given orally by you at home 3x weekly.  It has broad anti-cancer activity, and studies have shown that it retards the growth of HSA cells.  You are WELCOME to purchase it from us after your consult.

3) FIDOCURE IMMUNE THERAPY:  FIDOCURE can test your pet's tumor biopsy for genetic markers which may allow the use of oral anti-cancer drugs from human medicine, given by you at home.  This approach can markedly increase survival times in many forms of cancer.

4) HSA VACCINES:  There is a BUNCH of work being done on tumor vaccines, which enlist your pet’s own immune system, instead of drugs, to fight the HSA.  While expensive, this approach has shown improved survival compared to the chemotherapy mentioned above.  Study 1, Study 2, Clinical Trial

5) METRONOMIC CHEMOTHERAPY:  These are micro-doses of oral chemotherapy drugs given  by you at home.  Most dogs tolerate this very well, and of course the big advantage is that this is truly home care.  Metronomic chemo has shown to extend survival in other forms of sarcomas.  Studies on HSA have been mixed, with some showing improved survival and some showing no benefit.

6) CURCUMIN has been proven to not only kill HSA cells directly but also to interrupt cancer growth pathways.  It also has broad anti-inflammatory properties.  The best on the market is our own Longevity Plus, and if you read up on it you'll understand why. 

7) TURKEY TAIL MUSHROOMS:  A 2012 study at UPenn showed increased survival for splenic HSA dogs when treated with a turkey tail mushroom extract called Im-Yunity.  You can find this online, and we also carry a turkey tail mushroom extract.

8) YUNNAN BAO: This is a Chinese herbal preparation that can be purchased online.  It has traditionally been thought to reduce bleeding tendencies – always a good thing with HSA – and more recently was proven to actively kill HSA cells.


If you have questions or just need a sympathetic ear, my email is ktomandvm@gmail.com.