Vaccine Associated Sarcoma (VAS) is the new name for the vaccine induced fibrosarcoma (cancer) previously called, vaxosarcoma, of cats. While the combo respiratory and cat fever, FVRC-P, vaccine is safe, Feline Leukemia (FeLV) and Rabies may not be. No particular brand of FeLV or Rabies Vaccine is identified as the cause. Dr. Dennis Macy of C.S.U. says, "Cats should not be unnecessarily vaccinated (i.e. annual vaccination for rabies with a three year rabies product should be discouraged). None of the killed FeLV or Rabies vaccines should be given in the inter-scapular space (between the shoulder blades). Vaccines administered S.Q. on a limb may be preferable. Your vet should use only the single dose Rabies vaccines (not the multiple dose type) and give it under the skin behind the knee on the right rear leg and FeLV on the left rear leg with documentation of the manufacturer. These precautions will minimize problems. Vaccines given into the muscle just makes detection of cancer more difficult."

If you find a lump between the shoulder blades of your cat, suspect a Vaxosarcoma. See your vet for a biopsy. Do not attempt simple surgical excision as it is seldom curative. Even aggressive wide surgical excisions are often incomplete." Dr. Macy recommends radiation therapy be included either before or after extremely wide surgical excision; however, recurrence is common and death results.

Our Cancer Center's protocol for Soft Tissue Sarcomas is the most aggressive approach to any soft tissue sarcoma and especially for Vaxosarcoma of cats that is being used in the entire U.S.A. Our data suggests that tumor bed implants with carboplatinum chemotherapy along with intraoperative radiation therapy into the tumor bed is effective in long term survival. Chemotherapy is given as a radiation therapy enhancer along with 10 fractions of external beam radiation therapy totalling 5,000 cGy to the tumor bed over a five week period sarting two weeks after surgery.

Cats are rechecked monthly with follow up chemotherapy for six to eight months. Hair returns 2-4 months post treatment. The fur often grows back a different color.

Cases may be received from anywhere in the world. Our pick up service from LAX will deliver pets with any type of sarcoma to our facility promptly and safely. We have successfully treated cases as far away as Vancouver. We have declared war on Vaccine Associated Sarcomas and we are winning! Our data shows that 13 cats admitted to our Center that were treated had only a 33% recurrence in 100 weeks whereas most institutions report a 50% recurrence in one year. The management decisions which you and your vet make at the very onset of any cancer determines the chances of successful treatment and patient survival.

The ideal VAS referral for us is a cat that has been diagnosed with the cancer via a small true cut or wedge biopsy only. A small biopsy will not disturb the primary tumor. If we have the first surgical and intraoperative procedure for that cat, we have the ideal referral.

Ask your vet!

Vaccine Lumps What should I do?

About five years ago young woman who was referred to our cancer treatment service made an amazing observation. Her cat developed a lump over his shoulders which was surgically removed and a sample sent for biopsy. The biopsy report showed that the lump was a malignant cancer known as fibrosarcoma. It is a soft tissue cancer which has an invasive nature and likes to regrow despite surgical removal. This young woman said that she knew of two other cats that had developed similar lumps in the same general location. She said that she was suspicious that these lumps may be caused by something that all three cats had in common such as vaccinations of some kind.

This young woman made a tremendous observation. It seems that this kind of cancer was noted to be increased on the East Coast by a veterinary pathologist who published her findings and suspicions. She said that the fibrosarcoma cancer was increased by 68% since the use of Feline rabies vaccinations were allowed to be given under the skin rather than in the muscle.

Veterinary scientists seem to think that a commonly used agent, ammonium hydroxide, which potentiates the immune response to vaccines may be the cause. Veterinarians and pet owners alike are concerned. For the moment, it is prudent to switch to single dose vials for Feline rabies vaccines and administer them under the skin in the right rear leg as distal as possible at the level of the knee. Also pet owners should be advised to examine the vaccine site for any lumps that form. If the lump enlarges or does not reduce to nothing in 3-8 weeks, a biopsy is needed. A fine needle aspirate which sucks cells from the mass is not adequate to evaluate this type of lump. Sarcoma cells do not get into the needle easily enough during aspiration to give your vet a reliable negative result. An experieced cytologist will miss the diagnosis if the cells are not on the slide! I like to use a large 18 guage needle and I deliberately jab tissue loose to fill the core of the needle with representive cells for my slide examination. That jabbing motion cuts enough tissue so my sample is reliable.

If you notice a lump near a vaccine site, it should be officially biopsied with a true cut or wedge sample first and foremost. Discuss the biopsy results with your vet. If you can't get to a referral hospital that handles this nasty octopus-like cancer, then locate a good veterinary surgeon so it can be aggressively removed surgically with a 5 centimeter, extremely wide margin. Those margins (edges) must be sent in for biopsy. Unfortunately over 95% of these innocent looking lumps will return with simple and even wide aggressive surgery. That is why we recommend referral before any attempt is made to remove the mass.

Sadly we see cats presented to us after 2-5 recurrences. Or we will see cats that had false negative aspirations of the tumor months before so the owner did not know that the mass was malignant. These cats are at an extreme disadvantage.

If the lump is malignant, large, has satellite lesions or returns once, an immediate referral for consultation at our facility, the VCA Animal Cancer Center, is the option that may save your cat's life.

The soft tissue sarcoma protocol offered at our facility is the most aggressive combination treatment for sarcoma in the pet world, because we introduce a chemotherapy implant and a megadose of radiation therapy into the open tumor bed during surgery. This is perceived to reduce the growth factors that normally function in wound healing that may retard viable cancer cells from recurrence. A follow up program of 10 additional radiation treatments is started two weeks after the initial procedure after the wound is healed.

Your location is not a problem. we are located 15 minutes from LAX and we will be happy to pick up your cat at the airport and board your cat during the treatment. We happily celebrated a 3 year anniversary for one cat from Vancouver and a one year tumor free anniversary for "Yodette" from Stanford! Ask your Vet!

updated 11-22-98

By Dr. Alice Villalobos
VCA Coast Animal Hospital
and Cancer Center, Hermosa Beach, CA
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