Melanomas- Treatments? Experiences?

[dressage_ryder]

I have an 8 year old Andalusian gelding. I've known him since he was a weanling, and he first developed a few melanomas around his anus when he was 5. They didn't grow much at first, but in the past 6 months, they have grown rapidly. he now has a large cluster around his anus and several (10-15) small ones on the underside of his dock. they don't seem to bother him at all, but they really really worry me. It wouldn't worry me if he were 20 years old, but he's still so young. I've talked to several vets, none of which are very interested in treating him. 2 vets told me to try Cemeditine, which i'm going to start this week. has anyone else tried this? what dose did you use and how often and for how long? any experiences (good or bad) would be greatly appreciated.

[rcloisonne]

There have been numerous threads regarding melanoma in the horse. Try the search feature.

Here's an up-to-date article published in The Horse. You'll have to sign up to see the whole article but it's free.

BTW, you should be getting the "how much and how oftens" from your vet regarding cimetidine.

From: The Horse
Don't Ignore Melanomas
by: Marcia King
October 01 2008, Article # 12755
http://www.thehorse.com/ViewArticle.aspx?ID=12755

The latest research indicates that equine practitioners and the general public need to understand that a melanoma is not just a benign bump.

The statistics are a little daunting:

1. Up to 80% of gray horses older than 15 years will develop at least one melanoma, a type of cancerous tumor.

2. Approximately 30% of equine melanoma cases seen by at least one referral hospital had developed into extremely large, advanced, infiltrative, multinodular, metastasizing (spreading) or multicentric (having multiple centers of origin) lesions.

3. All melanomas are malignant (even the tiny ones) and possess the propensity to have further and unpredictable patterns of growth.

Non-surgical treatment options:

Cimetidine: Opinions are divided on cimetidine (an anti-ulcer/heartburn medication). "Cimetidine has a good reputation with most practitioners for shrinking tumor size," Graves reports. "But owners should know that some horses become 'resistant' to the drug's effects. If that occurs, some veterinarians suggest stopping the drug for two to three weeks, then restarting therapy. The second round may or may not be effective."
Robertson feels there is insufficient scientific data to support cimetidine use.

Cisplatin: "Intralesional treatment with cisplatin (an antineoplastic drug, meaning it inhibits the growth and spread of malignant cells) in oil was shown in one study to be effective in shrinking tumor size," says Graves. "This is not a common therapy, though."

Frankincense oil : This oil, injected or applied topically, has had some success in reducing tumor size, says Robertson, who is currently researching its efficacy in melanoma treatment. "It is much too early to tell if this oil kills all melanomas."

Vaccines: Melanoma vaccines or immunostimulants for treatment or prevention is without sufficient positive research data to support use, Robertson states. Nevertheless, Graves reports that, although she has had no personal experience using the vaccine to treat melanomas, some of her colleagues "have been happy with its efficacy in shrinking masses."

[Altitude Rider]

Sorry you have to deal with that!! I am going through the cancer thing too with my old gray guys.

My 23 yo Arab has melanomas and my vets won't touch them though they don't sound as bad as yours. I have heard positive things about the cemetidine but I am not using it. In your case it sounds like it would be worth using that product since he is so young.

My 20 yo half Andalusian has squamous cell carcinoma and the vets are more worried about that than the melanomas in the Arab.

I use Frankensense oil with both of them. I had one vet recommend it and some other people have mentioned it. Both my cancer horses react to it (lip smacking) and want to take it out of my hand. I use it when I treat Cody with the chemo cream along with Orange oil. Does it help? I don't know but it wasn't overly pricey so I got it.

A friend had an Arab with the large melanomas on the anus and they just did their best to keep them clean.

Good luck and post results of what you try please.

[dressage_ryder]

Thanks for the replies. Where can you get the Frankenscence oil from? I've heard of it, but none of the vets had heard about it. I had conflicting advice from 3 vets about the Cemiditine dose/kg, which is why i wondered what other people had used. Has anyone had luck with cisplatan injections?

[X3allie]

My trainer had a pony with melanomas. She was put on cimetidine before we got her. It seemed that in the time we had her it shrunk the tumors slightly, and when tumors started to spread again we upped the dose. Unfortunately we lost her before we had a chance to see if the higher dose would have helped.
Our vet seemed to think that the effects the drugs had were hit or miss

[thatmoody]

We use Cimetidine in two horses we have with melanomas (both greys, both geriatric). It's working quite well in one, but not too much change in the other (although it does seem to have halted the growth). The dosing is quite a pain in the butt, because you have to dose during the night. We discontinued it on the horse that it's NOT working with, due to the difficulty in administration. He's the older of the two anyway (29 as opposed to 21).

[rcloisonne]

This is by no means carved in stone but typical dosage used to treat melanoma in horses:

Cimeditine provides the greatest therapeudic benefit in equine patients with melanomas that are actively increasing in size and number. Its effect on melanomas that have not changed in size or appearance for many years is minimal. Cimetidine is administered orally at a dosage of 2.5 mg/kg three times daily. If the drug cannot be administered in this fashion, the total daily dose (7.5 mg/kg/day) can be divided into one or two daily doses, however horses treated every eight hours have responded (subjectively) best. If there is no change in the size or number of melanomas after three months of treatment, therapy should be discontinued. If there is a continual decrease in size and number of melanomas, therapy should continue until two to three weeks after a positive response is no longer apparent. The progression of the disease may be halted for months to years after the cessation of treatment, even if there was no clinically observable response to treatment.

http://www.miravalandalusians.com/garbosa/melanom2.htm

[Tif_Ann]

My 24 year old gray thoroughbred has responded very well to Cimetedine. I've posted about him multiple times in the past so you should be able to find his story. He recently was diagnosed with ringbone as well, so we stopped the Cimetidine (figured why fight the tumors so aggressively now that he has another progressive disease and will be retiring in a year anyway) ... but the largest remaining tumor started to swell up so we've restarted the Cimetidine. My vet says one theory about how Cimetidine works is it cuts off the blood flow to the melanoma, so we're assuming the "swelling" is blood flow returning to it. Rocky is on 1200 mgs 2x per day.

[springer]

My 3 yr old andalusian already has 2 melanomas- and I had some success with Cimetidine with my other grey horse so we are putting this guy on a course of it for 3 months- 16,000 mg/day split into 2 feedings. (The tablets are 800mg each- 10 tablets per feeding).

[dressage_ryder]

I started my horse on the Cemitidine today, 800mg tablets. He won't eat them!!! :-( I crushed them up with a hammer and mixed them in applesauce in his grain (he gets a mix of beet pulp, bran sweetfeed and pellets). he had a mouthful of his feed and wouldn't eat the rest. Any tips? I may need to look into the flavoured liquid from a compounding pharmacy but it's even more expensive. I don't know how i'll get the pills into him three times a day.

[springer]

I started my horse on the Cemitidine today, 800mg tablets. He won't eat them!!! :-( I crushed them up with a hammer and mixed them in applesauce in his grain (he gets a mix of beet pulp, bran sweetfeed and pellets). he had a mouthful of his feed and wouldn't eat the rest. Any tips? I may need to look into the flavoured liquid from a compounding pharmacy but it's even more expensive. I don't know how i'll get the pills into him three times a day.

I use brown sugar. Got the idea from these forums, actually! Mix about a TBSP with about a cup of warm water and pour it over the stuff. He's gotten used to it and now eats it pretty well (my boy gets a similar mix of feed to yours BTW)

[BeastieSlave]

You'll find many old threads if you search for "Cimetidine" and "melanomas".

I recently lost a pony who had been on Cimetidine for nine years at least. For the last year or so she was getting 3,200mg/day. I was lucky because I could just snap the tablets in half (she got 400mg tabs) and drop them in her feed and she'd eat them.

The thing to remember is that you have to give the stuff time to work. Don't give up if you don't see changes right away. In my pony's case, I didn't see any change at first, it was just that the ulcers stopped growing for a long time. That was good enough for me! When they did grow, I was happy that the they weren't ulcering and kept on with the Cimetidine. The stuff isn't expensive, might help, and won't hurt.

Good luck!