Grey Horse Melanomas

Questions for the Vet

(The picture above is Katie opening the latch to her stall.  She has mastered every lock on the property!)


I have noticed a small cluster of new masses under Katie’s tail over the last several weeks.  Katie has always been extremely defensive of her back side, and it is almost impossible to get a finger under her tail.  When the vet came out to give annual immunizations last week, I had her check Katie’s melanomas.  Thanks to the Nublada’s Cure that I’ve been using for years, existing melanomas on her chest, teats and the one under her tail have pretty much remained stable with no changes.  But there are now a few more under her tail that were not there before.  Following are my vet’s  comments:


Additional info:

See if you can go on thehorse.com and view the video webinar on grey horse melanoma. It is rather lengthy, with some interesting treatment options discussed at the end. One is frankincense oil injected intralesionally or applied topically. The other involves electric pulses to cause tumor cell membranes to "leak." In BOTH cases, the lesions got very messy as they were resolving, so the care needed during and after treatment would require a cooperative horse and committed owner. You would have to be willing to try an experimental treatment while enduring the aftereffects of the treatment. Perhaps UGA's medical people could consult with their oncology department and advise you further on this or other new treatments.

 

One question I have not heard answered yet is this: What percentage of horses with visible external tumors already have significant metastasis to internal organs??? Katie would likely be considered Stage 4 due to large lesions (chest, abdomen, tail) in multiple locations. We know you have seen lumps for years, so I suppose there would be some risk of internal melanoma. The tumor GRADE is a histologic/microscopic diagnosis, and requires biopsy and histopath to tell how aggressive it is. If you view the video, this particular equine specialist debunks the idea of surgical removal of skin lumps CAUSING metastatic spread - he cites studies that say this is not likely to be the reason for spread. In fact, he cites evidence that genetically, some horses and people have cells associated with melanoma throughout the body without surgery.

 

This is a very interesting topic, and one where information is still evolving. I hope you can view the video.

 

I have some experience with the melanoma vaccine - I had a dog patient with oral melanoma (very aggressive in dogs in the oral cavity). They had the mass resected twice, once by me at Chestatee where it was diagnosed via histopath, and again at GVS specialty hospital where I referred them for follow-up. At GVS they consented to the melanoma vaccine treatment. Ultimately several thousands of dollars and months later, the melaoma returned, and the pet was euthanized. "Success" according to oncologists sometimes consists of temporary remission of the tumor. So although it may have been successful, the outcome with or without the vaccine was the same. The vaccine is used in human oncology as well, but we have to be careful assuming the same outcome in other species. The vaccine is expensive, and still fairly experimental, but may be worth considering.


Dr. Pam