Hemangiosarcoma (HSA) is a very rare and aggressive cancer in cats. And, unfortunately, because it is so rare, there’s also very little information about treatment and outcomes. However, HSA does occur somewhat frequently in dogs and cats are often able to tolerate the same medications as dogs so treatment is possible.

What is HSA?

Hemangiosarcoma is a cancer of the blood vessels (veins, arteries, capillaries). Any place in the body can develop HSA, because blood vessels exist everywhere. And, because blood vessels are everywhere, HSA also has easy access to the rest of the body to metastasize (spread).

In cats the most common place for HSA tumors to be found is in the skin. These tumors can often be found through regular grooming of your cat (by yourself or by a professional groomer). Anytime you or your groomer finds a new or changing lump on your cat it’s important to follow up quickly with your veterinarian. The lump may be nothing serious, or may be an aggressive cancer like HSA.

HSA also occurs inside the body. In cats the most common place for HSA to begin is in the lungs. In dogs, and in my cat Oliver (who thinks he’s a dog) the most common place for this cancer to begin is in the spleen. You can read about Oliver’s experience with hemangiosarcoma at https://www.gofundme.com/f/oliver-fights-rare-cancer. His fundraiser page contains detailed information about his symptoms, diagnosis, surgery, initial recovery, chemotherapy, and see details on the costs associated with his treatment.

No matter where this cancer begins it will spread quickly. The most common places these tumors will spread to are the lungs, spleen, and liver. But nowhere in the body is safe.

How is HSA diagnosed?

Symptoms of hemangiosarcom depend on where the tumors are and how much they have spread. Cats with noticeable skin tumors are often diagnosed without any symptoms other than having a new or growing lump. Cats with internal tumors are more likely to be diagnosed after exhibiting sings of weakness, pain, difficulty breathing, or lethargy. These symptoms are usually due to a combination of anemia and internal bleeding because HSA tumors often rupture and bleed causing severe anemia.

The actual diagnosis of hemangiosarcoma requires a biopsy and histopathology.

How is HSA treated?

Treatment of HSA also depends on tumor location and the symptoms the cat is experiencing at the time they are diagnosed. Generally this means surgery to remove the primary tumor and chemotherapy to prevent growth/spread of the cancer. For cats with internal bleeding and/or anemia a blood transfusion may be required.

If the HSA is in a superficial skin tumor surgery alone may be enough to be curative. But for tumors within the organs surgery alone is unlikely to cure the disease. Treatment with chemotherapy, usually with doxorubicin, has been shown to increase survival times. Due to the rarity of HSA in cats there’s not a lot of statistical data available, but most cats who receive surgery and chemotherapy for HSA live 6-9 months after diagnosis and have excellent quality of life during that time.

If your cat has internal tumors it is strongly recommended that you have an esophageal feeding tube placed at the time of their surgery to remove the tumors. Following major surgery kitty is not very likely to want to eat or drink much on their own and a feeding tube can make a major difference in their survival and their quality of life during recovery. Feeding Tubes has information about when to get a feeding tube and how to use and properly care for them.

Yunnan Baiyao for Bleeding

The herb yunnan baiyao is excellent for the treatment of bleeding and is a common part of the treatment plan for cats with HSA. For cats with large internal tumors, or multiple internal tumor sites it may be beneficial to keep them on daily doses of yunnan baiyao. If your cat isn’t taking yunnan baiyao daily it’s a good idea to have some on hand in case of emergency. Any reputable local herb store (particular Chinese herb stores) should carry yunnan baiyao, and there are many online retailers who carry this herb as well.

One very important thing to know about with yunnan baiyao is The Red Pill. The red pill is a special pill that comes with yunnan baiyao and is uses in emergencies. If the cat is actively bleeding internally when yunnan baiyao is first started then the red pill is given along with the first does. Otherwise the red pill is used if bleeding had been controlled for awhile and has suddenly started again or if the cat suddenly develops signs of anemia. The red pill is somewhat hidden in the package and you wouldn’t know that it exists unless someone tells you about it. You only receive ONE red pill per pack of yunnan baiyao, so do not throw it away even if you finish the rest of the capsules in the pack. You cannot purchase the red pill separately.

Yunnan baiyao comes in loosely packed gelcaps. These gelcaps are a little too large for most cats to swallow easily, so you may need to put them into smaller gelcaps before giving them to your cat. Pilling Cats and Using Gelcaps for Pilling can give more information on how to give the pills. Yunnan baiyao has a very strong smell that’s not entirely pleasant to cats so you are not likely to be able to syringe it into their mouth with water or hide it in food or treats easily. The red pill does not have a strong smell so that one is much easier to give than the herb itself.

Support Groups

Feline Cancer, Feline (Cat) Cancer Support Group, and Cats with Multiple Medical Conditions are all Facebook groups that may be helpful.