We did move forward with treatment yesterday. I got to the barn before the vet, and there was quite a lot of edema in the area. He took that as a somewhat positive sign, in that the body was starting it's own immune reaction to the growth. He does not like the surgical option, as in his experience, it's very difficult to get all underlying tissue, particularly since most of her tumor is "occult" or "plaque" type- i.e., the flat portion of it.
Step 1 started yesterday. He injected the tumor in several places, but focused on and under the large nodule, using
cisplatin, essentially a chemotherapy drug. She will be given about 2 weeks to see if this causes an immune reaction which triggers sloughing of the skin. Vet said this will increase the edema significantly- he wouldn't be surprised if she's swollen to the size of a softball under there in the next couple of days. From there, if the tumor does begin to die, it will get worse before it gets better, producing a really large, open wound (getting "angry," as Super Nova described). Part of the reason for not debulking with surgery is to provide an injection site if we continue this approach.
If the injection doesn't seem to have any affect, then we will move to option 2, which will be topical treatment with
Aldara cream. From what I've read, this does seem to have good results, but again will be accompanied with a really nasty open wound before healing eventually begins in 2-4 months.
The flies are definitely concerning me in either of these treatment options, as from looking at extensive pictures of other horses in treatment, I know what's coming, and this is absolutely the worst time of year for it. I've only really ever dealt with scratches and scrapes, so all I really know to do for flies is clean thoroughly with Betadine scrub wash and then cover liberally with SWAT. What else would you be doing with a much more significant wound that really can't be covered?
I think what's most frustrating about all of this is that I know this likely won't be the last sarcoid we deal with. Everything I've read indicates that once you begin treating, you're almost guaranteed to have another one pop up somewhere else in the future. I guess I can only hope that they never show up around her eyes, as those seem the worst.
Here are a couple of pictures from right after the injections yesterday. The pictures really hide the swelling, but it was pretty significant. The pictures also don't do a great job of showing how the texture of the nodule had already started changing. In person, it reminded me of the texture of a seed after you soak it in water- turning a little wrinkly and opaque. And just for comparison, the last picture is what it looked like back on June 30th- you can see how quickly the change has happened.
I'll plan to update this throughout the process in case it will be helpful for others making treatment decisions in the future. I will say I got some great advice regarding when to treat from one of the Minnesota vets involved in the Aldara study- she said a useful rule of thumb was that when the sarcoids are pea size, they're probably fine to leave, but when they become grape size, it might be time to start thinking of treatment. Obviously a judgement call for vet and owner.
