Vaccine induced sarcomas are a specific type of cancer caused by the injection of a vaccine. This type of cancer is highly aggressive and requires wide surgical excision to remove. The sarcomas begin as a firm mass under the skin. Based on location and behavior it is recommended that they be surgically removed and submitted for biopsy. I have seen many cats of all ages and breeds, and ages present with their parents concerned about a marble sized knot they stumbled upon while petting their cat. The mass can be painful when palpated, but for some cats it seems to to be bothersome at all. Unfortunately, even with an early diagnosis and surgical intervention most of my patients have recurrence of their cancer and succumb to the sarcoma in a matter of months. The prevalence and nature of this has influenced not only how often we vaccinate our cats but also where we vaccinate. Veterinarians started moving the placement of the vaccine from the shoulder blade area to the extremities when the American Association of Feline Practitioners recommended that vaccines be placed below the elbow or stifle. We also began using three year duration of immunity vaccines instead of annual vaccines.
Cats with sarcomas require aggressive surgical excision with wide margins. Excision for a sarcoma in the shoulder blade area, in many cases, needs to include the dorsal (top) aspect of the spinous processes of the vertebrae. This includes the skin all of the underlying muscle and the top part of the spine. For a general practitioner this surgery is beyond our comfort zone, or ability, so these patients are referred to specialists. The cost of this surgery is in many cases considerable leading many owners to decline treatment. The hope with placing vaccines low on the limb was that if, or when, a sarcoma occurred that the leg could be amputated to remove the cancer and hopefully save the cat.
For those of us who love our cats the thought of a vaccine costing our pet’s life or limb seemed too much to pay. Some clients chose not to vaccinate and others want to vaccinate even less then every three years. The cost-benefit decision was significantly altered by the fear of sarcomas.
Enter Dr. Levy of the University Of Florida College Of Veterinary Medicine. She has just released the findings from her study on feline tail vaccinations. She estimates that “1 to 10 cats out of 10,000 vaccinated against infectious diseases develop cancer at the infection site.” Dr. Levy studied 60 cats and found that using the tail as an injection site was just as effective and should a vaccine cause a sarcoma or require excision the tail is an easy structure to remove and will not disfigure or alter the cat’s ability to function normally. Dr. Levy recommends vaccinating as distally (down the tail away from the body) as possible. She also notes that cats tolerate tail vaccination as well as they do in traditional sites.
After reading Dr. Levy’s study I hesitantly jumped on the band wagon. Cats are not the easiest patients. The traditional spot of vaccinating between the shoulder blades was chosen because their is ample skin, less chance of being bitten, and it is the place our assistants scruff to hold our patients still. Admittedly, when I first read the article I thought, "this is never going to work." There just isn't enough room to hold safely, and there isn't enough skin to tent to place a SQ shot safely. But if it can save a cat I'm going to try. So, with some trepidation I vaccinated my first cats for a local rescue during their spay/neuter clinic. These cats were waking up from anesthesia and provided a quiet, calm patient for my first vaccination attempts. (Note about vaccinating anesthetized patients..)
I will add a few first impressions. It is difficult to tent the skin in the distal tail. The traditional 22 or 23 gauge 1 inch needle is too long and a bit large to place in the distal tail. I do think that it will take me a while to get used to this protocol. The standard pulling the plunger back to make sure that we are not in a blood vessel before we inject the vaccine needs to be done faster and I in inadvertently hit bone with each attempt when trying distally. Also, if you are placing multiple vaccines it is difficult to get enough SQ space to place them. Lastly, every site I used bled. So, be prepared to hold off those bleeders, and hold the cat, and not stick yourself. Like everything else "practice will make perfect." I hope.
I will keep you all posted as I transition to the more “lively” patients.
Dr. Levy’s study is published in The Journal of Feline Medicine and Surgery.
I posted this picture on my Wordless Wednesday blog and I received this from a reader;
"I read your blog – love it.
I wanted to comment on your Dec 18 entry – but not on the blog. You have a picture of a cat that you just spayed and are giving a vaccine into the tail. I am assuming that the cat is still under anesthesia since you say: “a nice, quiet pet to practice this on.” My concern is that it is not advisable to vaccinate a pet when under anesthesia. Not that I want to criticize – I just read a lot and have come across this many times – and feel that I should share this with you. I have attached a link to an article that is posted on the rabieschallengefund.org website and is authored by Dr. Dodds and Dr. Schultz who you are probably familiar with."
I sincerely appreciate her reminder! We all learn together, so please never hesitate to offer your opinion, advice, or experience. It is my sincere hope that this blog is an exchange of information to help pets worldwide.