Mast cell tumors on penis.

Dr. Marie replied:

I'm sorry to hear that Tyson is not doing well.

Mast cell tumors can sometimes be very difficult to deal with. Sometimes, just removing a mast cell tumor can cure the problem. However, if Tyson's are deeply invasive then surgery may not be an option. Or, if surgery is an option it will be an expensive one.

The drugs that you mentioned (prednisone, Lomustine (also known as CCNU) and Vinblastine) actually are a chemotherapy protocol. They are not simple medications that you just get a prescription for. Rather, under the direction of a veterinary oncologist you would have repeated visits and Tyson would get injections intravenously of these medications. He would also need repeated blood tests to make sure that his red and white blood cells are handling the chemo ok. This type of chemotherapy is something that is often suggested to use after a mast cell tumor has been removed, in order to prevent remaining cells from spreading. However, removing these tumors likely isn't an option for you.

If I had a patient with this problem and surgery and chemo was not an option then I would do something called a palliative treatment. In this case I would prescribe antihistamines to help against the histamines that mast cells release and also stomach protectant drugs. Sometimes I also do prescribe prednisone (which you mentioned above.) The prednisone can help reduce swelling but is not going to cure the cancer. While some of these drugs can be purchased over the counter, they need to be administered under the advice of a veterinarian. (I can't legally advise you on dosages and use of medications without actually seeing your dog in person.)

It will be hard to know when it is time to talk about putting him to sleep. Here are some things to consider:

1. Is he enjoying life more often than not? If you feel that he is obsessed with the tumors all of the time, then this is not fair and we should be thinking about euthanasia.

2. Is he still eating ok? Lack of appetite can be a sign of pain.

3. Are you enjoying having him? If Tyson's care has become a chore, or if he is oozing and bleeding all over your house then these are valid reasons to consider euthanasia.

I do find, however, that in most cases, my clients just "know" when it is time.

Please let me know if you have more questions.

Dr. Marie.

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