Melanoma and Melanocytoma

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Melanoma affecting an eyelid in Labrador

Question: Dear Dr. Richards,

You helped me with my black Labrador's squamous cell carcinoma on her nose. As I wrote to you a couple of months ago, she has been thriving; however, she has had a small growth on her eyelid for a few years. Even the oncologists said just leave it along unless it starts growing. It's just been diagnosed by my vet as melanoma, covering one third of her eyelid. I have an appointment with the oncologist who did the surgery on her nose next week, but this thing is growing fast. I know we can't violate this poor animal's body by removing her eye. My regular vet had mentioned cryogenic shrinking. If this is not an option, should I have my family vet do the surgery (he charges considerably less) or have the oncologist perform the surgery (she charges about 3 times more). Can you explain what I might be looking at here? She's only seven years old. If she were an old lady, I wouldn't consider putting her through any more. Thanks in advance, Kathryn

Answer: Kathryn-

In the case of a melanoma affecting an eyelid, I don't think that it is necessary to have an oncological surgeon remove the tumor. However, it is best to have someone remove the tumor who is going to be aggressive enough to remove a wide margin, which may make it necessary to repair the lid margin using a corrective surgical procedure. This is not especially difficult and many general practitioners can do this surgery -- but many do not and may be reluctant to remove adequate tissue without knowing how to repair the lid margin. So I do think it might be worth discussing this with your vet. If he is comfortable doing this kind of surgery then there is no problem. If he is not, I would think an ophthalmologist or a board certified surgeon would both be good alternatives, although both would probably charge more than a general practitioner for the surgical procedures.

It is important to have the margins of the removed tissue examined by a pathologist to determine if there tumor has spread beyond them and it helps to know if the tumor seems to be arising from the skin of the lid or the conjunctival tissue (the skin of the lid seems to be less likely to form aggressive tumors). Radiation therapy can be helpful. Removal of the eye, if it seems as if it might contain the tumor, is a reasonable option. Dogs generally seem to do very well after removal of an eye and I would not hesitate to remove an eye from one of my dogs, if I thought that it would be helpful in controlling the spread of a tumor or in controlling pain associated with glaucoma or other eye diseases.

Mike Richards, DVM 10/17/2000

Melanoma

Q: I was told that my 12 year old black Schnauzer has melanoma. I cannot find any info on your website.

Please advise, Budd

A: Budd-

A melanoma on the skin of a schnauzer has about an 80 to 90% chance of being a low-malignancy tumor. These do not usually recur after surgical removal if a wide incision is made and tissue removed under the melanoma, too. It is a good idea to have tumors suspected of being melanomas removed and examined by a pathologist, who can give some idea of the potential malignancy. If it seem appropriate after examination by the pathologist chemotherapy can be used to try to limit the spread of the melanoma. Malignant melanomas sometimes in the skin of dogs and these are much more serious. Most malignant melanomas occur in the oral cavity or on the toes of affected dogs. These are much more serious and recurrence or spread of the tumor to other tissues is very likely.

I hope this is a benign tumor.

Mike Richards, DVM

Melanocytoma - benign now but precancerous

Q: Mike,

Thank you for the note about my Black Schnauzer's possible melanoma, and your advice about it. It is a benign melanocytoma, which I am told is precancerous. 1. Would zapping this with liquid nitrogen be OK? (would this be painfull to the dog?)

2. Would surgery, the way you describe with the wide incision and tissue removed under the tumor, be advised.( would this be painfull )

or

3. Just leave it alone.

He is such a good dog, he is 12 years old and the thought of hurting him or disfiguring him is more than I can bare.

Please advise and again thanks.

The reason I didn't answer sooner is because I had new hip surgery myself and at 77yrs one doesn't recover that fast.

Best regards---Budd

A: Budd-

Unless the guidelines have changed very recently, the best treatment for any melanoma is still considered to be radical (aggressive) surgical excision. For some reason the histologic (microscopic) appearance of these tumors is not as reliable as it is for most tumors so it is usually better to be safe than to be sorry.

Most dogs recover from surgical removal of these tumors very rapidly even when a large area of skin and underlying tissue is removed. Pain relief is available through several effective medications now, so post-operative pain can usually be controlled.

Your dog's age is a factor in making a decision on the treatment options. Somewhere between 25 and 50% of melanomas are malignant when they arise from normal skin (not oral or at a junction between normal and specialized skin like around the nose, lips, etc.) You have to factor that risk against the probable remaining lifespan of your schnauzer and then try to figure out what the best option is. It is sometimes a difficult choice. If he is healthy in most other respects surgery makes more sense than if he has another disease condition that is threatening his quality of life or threatening to shorten his lifespan.

Hope this helps in your decision making.

Mike Richards, DVM

Oral Melanoma

Q: Dear Doctor, I have an 11 year old black lab. about 7 months ago we discovered a large (quarter size) melanoma on the back of her tongue. It was removed an pathology looked good for a complete removal. She then underwent 4 chemotherapy treatments spread over 4 months. Her chest x-rays were all normal. Recently, chest films showed small masses in her lungs. The vet believes that further chemo would not be effective. Do you have an opinion. Who would serve as the best type of second opinion. Thank you for your help. TOM

A: Tom- The best second opinion in cases of cancer come from veterinary oncologists, as long as you remember that their bias is towards treating cancers. Most of them are pretty straightforward about the chances for success and pretty good at explaining what levels of success are possible (pain relief, increased quality of life, increased time before death or in some cases, a cure).

Our Rottweiler died of an oral melanoma that would not respond to treatment so my personal experience tends to make me think that your veterinarian is probably right.

I am sorry if this information is almost certainly too late to help you in making a decision. I hope that your vet and I were wrong in our assessment.

Mike Richards, DVM

Melanoma and Fibrosarcoma - is there a link

Q: Dear Dr. Mike, I have a 8 yr. old black lab/retriver mix recently diagnosed with fibrous-carcenoma (unsure of spelling). He has a protruding growth, redness and swelling along his upper gum/tooth line on one side. Approximately three months ago, Rufus had a small button looking malignant melanoma removed from the opposite side on his outer snout. These may not be related, but I know little of what to expect as to prognosis or treatment of canine cancers. Could you provide some general information about melanoma or fibrous carcinomas in dogs? Thank you. Rose

A: Rose- I can not find a link between the appearance of melanoma and fibrosarcoma in dogs but there may be one. In any case, this is a tough situation to find yourself in. Fibrosarcoma is not very responsive to chemotherapy so surgical removal and follow-up radiation may be the best course of action. The removal of these tumors is often very difficult due to their location and the need to remove healthy tissue around all margins for success. This makes it best to to have a surgical specialist and an oncologist to work with, making a veterinary school or large referral center the best choice in many instances (I am sure some general practices are competent in the surgery but few have radiation treatment ability).

Your vet can help you find a suitable referral center if you are inclined to go this route.

Mike Richards, DVM

Name of Clinical Study DNA Canine Melanoma Vaccine Principal Investigator Philip J. Bergman, DVM, MS, PhD; Head, The Donaldson-Atwood Cancer Clinic

Philip Bergman received his DVM from Colorado State University in 1990 and his PhD from MD Anderson Cancer Center in Texas in 1999. He is currently the Head of the Donaldson-Atwood Cancer Center and Director of the Flaherty Comparative Oncology Laboratory, both parts of the Animal Medical Center in New York. Dr. Bergman currently holds an adjunct associate faculty position at Memorial Sloan-Kettering Cancer Center and the Sloan-Kettering Institute for Cancer Research. He has presented his work at such venues as the Jean Holzworth Lecture series at Angell Memorial Animal Hospital, Japanese Veterinary Cancer Society and the American Association for Cancer Research Clinical Trials Symposium.

Purpose of This Clinical Trial The purpose of this study is to find out what effects the DNA vaccine has on malignant melanoma reoccurrence. This research is being done because there is a need for more effective treatments for malignant melanoma. We are extremely proud of our DNA vaccine program for canine malignant melanoma that has now generated this 4th study. We have a manuscript accepted for publication in the scientific cancer journal Clinical Cancer Research that reports initial findings of our DNA vaccine in dogs. These dogs had a median survival time of 389 days, a dramatic increase in survival (most dogs with advanced malignant melanoma have a median survival time of only 60-90 days with presently available therapies). There has been no toxicity noted in any dogs receiving DNA melanoma vaccines to date. To be Eligible For This Study, Your Dog Must 1) have a malignant melanoma (oral, toe or footpad), with or without metastases, 2) have an expected survival time greater than 8 weeks, without other serious disease, 3) have no evidence of brain metastasis, and 4) be able to travel to the AMC every 2 weeks for 5 visits (last four as outpatient visits).

http://www.amcy.org/department/ClinicalTrialsMelangreat50.htm

Last edited 08/04/05


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Michael Richards, D.V.M. co-owns a small animal general veterinary practice in rural tidewater Virginia. Dr. Richards graduated from Iowa State University's College of Veterinary Medicine in 1979, and has been in private practice ever since. Dr. Richards has been the director of the PetCare Forum...

 

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