Vaccine Associated Feline Sarcoma: Misty's Story

Despite the popular belief that all vaccines are both necessary and beneficial to your cat, there are sometimes hidden dangers that pet owners need to be aware of.

I'm a long time pet owner, and have experienced a lot with my cats over the years. Every cat I've ever had has been a rescue of a stray right off the street. Misty came to me as a 3 week old, 8-ounce baby, abandoned in a friend's yard, in October, 2004. We bottle fed and babied her, and she developed into a strong, seemingly healthy cat.

In the summer of 2005 - a particularly hot summer - Misty seemed to be sick. She was just lying around in the window all day, but so was her big sister, Jinx, so we weren't sure something was wrong. After a couple days, we decided to take her to the vet. Our suspicions were correct: Misty had a fever, and had we waited another day, she would have had to be admitted. After a cycle of antibiotics, she was back to normal.

Until the Fall, that is. Again she seemed not herself, and ended up with another round of antibiotics (one of these doses, either summer or fall, was an injection at the vet's). There had been a lot of activity in our house lately - replacing an old tile floor, using a strong new cleaning product (it made some of us sensitive humans sick, too!), and turning the furnace on for the first time of the season. We thought she might have allergies, so we'd keep an eye on her.

Misty's yearly physical and vaccines came President's weekend, 2006. She was a healthy 13 pounds, and was given her shots: 3-year rabies, 1 year distemper, 1 year feline leukemia. Within a couple weeks, we noticed a lump on Misty's leg. It was hard and solid, and she didn't like having it touched. It's not uncommon for cats to develop a temporary bump in response to a vaccine, but still we took her back to the vet. We were given some antibiotics, our vet made note of the lump's size, and we started watching it. We brought her back a few times for the vet to evaluate it; he was always very gracious and assured us it was getting smaller (at one point, 70% smaller than it was initially), but it's hard not to feel like you're overreacting.

In August, we decided to take her yet again, not satisfied with the lump's reduction (at one point, we had discussed removing it, but for simply "cosmetic" reasons, it seemed selfish and risky). At that appointment, our vet told us it had to come out - and soon. We scheduled surgery for the next week.

In the meantime, we dared look on the internet for what it could possibly be. Unfortunately, "vaccine associated feline sarcoma" was a frequent search result. I stopped reading, as it was too depressing; I would rather wait for the vet's results.

Misty's surgery went well, we were told. When we went to pick her up, we were expecting maybe a 1" spot where the lump was removed. Instead, we were greeted with the shocking sight of a 5" gash of long stitches, all of the fur on her right leg gone. A plastic cone was put around her neck to prevent her from picking at the stitches. Our vet - always amazing with the animals but definitely on the young and possibly inexperienced side - had suspected the vaccine associated feline sarcoma and had erred on the side of caution, making generous cuts in the removal of Misty's muscle and tissue. She now had 10% less muscle in her right leg, and we had to wait for the biopsy results.

As everyone dreaded, the biopsy confirmed that Misty's lump was in fact cancer. What now? Everything online was grim - amputations, chemotherapy, and high chance of reoccurrence. Most online stories had also had experience oncologists perform their pets' surgeries. Our vet had told us he'd never had such a case in his six years of practice. His father, also a vet, had one case in over ten years of practice. Though, tragically, common in some areas of the country, vaccine associated feline sarcoma was not common here. Such cases were also originally thought to be associated with the feline leukemia vaccine, but Misty's was on the right leg, and the vet told us the leukemia shot had been given in the left leg.

Naturally, we fought amongst ourselves. We should have taken her sooner. We should have insisted that something be done with the lump (though cancer would not respond to antibiotics, so why did it briefly get smaller?). We should have gotten a second opinion.

The lab report indicated that cancerous cells were detected to the edge of the sample, which concerned us. We had pretty high odds to overcome, as far as reoccurrence was concerned. On the plus side, our vet informed us that had they done a biopsy on the lump without removing it, the cancer cells would have spread. This eliminated some of the second guessing as to how we treated it.

Misty had a regular schedule of vet visits after that - 1 day, 1 week, 1 month later, and then once every month. Her recovery was quick; and we were happy to find that she had removed her cone after just a couple days, and had no interest in her stitches. Had she not gotten that off, we would've waited the full two weeks to remove it. It was sad watching her struggling to eat and sleep comfortably, but it was better than taking a chance on hurting her stitches.

Vaccine associated feline sarcomas are generally localized and will reoccur at the same spot before spreading. Our task was to monitor the surgery line and hope for no sign of lumps. After the three month mark, there was a far less chance of it reoccurring.

Misty has been lump-free for eight months now, and seems healthier than ever. I still hold my breath at each visit (which are now three months apart), hoping we didn't miss something. I declined Misty's booster shots this year, which my vet did not seem totally pleased with (Jinx and new sister Suki continue to get theirs). He was sure to explain the risks of contracting feline leukemia, and that she may not necessarily have a genetic predisposition that made her susceptible to the vaccine associated feline sarcoma. I just couldn't take the chance that she could have this all over again. We may end up getting a DNA profile done, to determine what would be safe for her in the future (is it just vaccines? Did the injection of antibiotics set something off?), especially when her rabies vaccine comes due. I feel she has been through enough, and if the only lasting reminder is a scar (which is totally covered by her hair) and a slight misshapen appearance of her leg when you look down at her), I am thrilled with that. It's just shocking to learn that the very shots you get for your beloved cat may in fact do more harm than good.