As I look forward to fall, I notice that October is Breast Cancer Awareness month, No-Shave November (Movember) is for Prostate Cancer, but what about the horses? Equine Cancer is a thing too, but I don’t see anybody giving horses their own cancer awareness month! What gives? Well I, the honorable Tony, am officially declaring August to be Equine Cancer Awareness month! And my first act to raise awareness is writing this blog.
Like other species, horses are susceptible to many different types of cancer. The most common in horses are melanoma, sarcoids, squamous cell carcinoma, and lymphoma. I’m a cat, so I like to keep things simple. Basically if you are a grey horse, you are going to get melanomas. If you are an Appaloosa or Paint horse with white around your eyes, you are likely to have squamous cell. If you are an unlucky horse of any other color, you could end up with a sarcoid or lymphoma.
If you own a grey horse, you probably already know what melanomas look like. They are usually firm, round grey nodules that commonly occur under the tail or around the external genitalia. Luckily I make it a point to spend at least 5 hours a day grooming my external genitalia, so I would be sure to notice a melanoma right away. Small melanomas are usually benign, but as they get bigger and the horse gets older, they are more likely to become malignant. But have no fear- there are new treatments becoming available!
Oncept, a vaccine that has shown promise against canine melanoma, is now being studied in horses. Now, why you would want to prolong a dog’s life is beyond me, but I guess not everyone can be a cat person. Oncept is going to cost you a pretty penny too: about $4,000 for the initial course of treatment. In addition to Oncept there is an autologous vaccine (that’s a vaccine made from the horse’s own cells–aren’t you impressed I knew that?) in clinical trials.
Sarcoids come in many forms. They can be flat, bumpy, warty, or a mixture. They can show up anywhere on the body. Depending on their location, they usually don’t pose much of a threat, just more of a nuisance. Kind of like me lying in the doorway so everybody has to step over me when they walk through the door. However, the smaller they are, the easier to treat. One treatment for these pesky tumors is a cream called Aldara (aka Imiquimod- say that 5 times fast!) There is also an herbal cream called Xxterra that has shown success in shrinking sarcoids.
Squamous cell carcinoma is not as friendly. As mentioned, it tends to occur on and around the eyes and eyelids of light-skinned horses, and sometimes on their private parts too. This form of cancer is aggressive and difficult to treat. Chemotherapy with 5-Fluorouracil or Cisplatin, radiation, and enucleation (removal of the eye) are the most common treatment modalities. Boy, I can’t wait to play cat Scrabble with Teanie this weekend. Fluorouracil, how many points is that?!
Last but not least, horses can get lymphoma too. Just when you thought colic and laminitis were the only things horses could die from. Lymphoma is sneaky. It is usually impossible to diagnose until a large tumor has already grown internally and spread to other parts of the body. Weight loss and lethargy are often the first sign. Bloodwork usually doesn’t show any striking abnormalities. Sometimes a mass is identified by ultrasound or rectal exam, but most often it is a diagnosis made via the process of elimination.
Lymphoma is sad because it is usually fatal within a few weeks to months. Treatment with steroids and chemotherapy is being studied at UC Davis vet school, but it is going to cost you a lot of Meow Mix for that big of an animal. Hence why we need to raise Equine Cancer Awareness to fund new research!
So class, what have we learned from exceedingly wise, supremely intelligent, impressively well-educated Tony today? Cancer in horses does happen! It doesn’t always carry a poor prognosis for a long and happy life, but treatment options are few and very costly. We need to raise awareness of equine cancer in order to further research into new treatments for this malady!
Now that I’ve exhausted myself with all this knowledge, I must get back to my nap!
Until next week,
– Tony
