Mast Cell Tumors in Dogs: some advances in conventional care
Dr. Demian Dressler is internationally recognized as “the dog cancer vet” because of his innovations in the field of dog cancer management, and the popularity of his blog here at Dog Cancer Blog. The owner of South Shore Veterinary Care, a full-service veterinary hospital in Maui, Hawaii, Dr. Dressler studied Animal Physiology and received a Bachelor of Science degree from the University of California at Davis before earning his Doctorate in Veterinary Medicine from Cornell University. After practicing at Killewald Animal Hospital in Amherst, New York, he returned to his home state, Hawaii, to practice at the East Honolulu Pet Hospital before heading home to Maui to open his own hospital. Dr. Dressler consults both dog lovers and veterinary professionals, and is sought after as a speaker on topics ranging from the links between lifestyle choices and disease, nutrition and cancer, and animal ethics. His television appearances include “Ask the Vet” segments on local news programs. He is the author of The Dog Cancer Survival Guide: Full Spectrum Treatments to Optimize Your Dog’s Life Quality and Longevity. He is a member of the American Veterinary Medical Association, the Hawaii Veterinary Medical Association, the American Association of Avian Veterinarians, the National Animal Supplement Council and CORE (Comparative Orthopedic Research Evaluation). He is also an advisory board member for Pacific Primate Sanctuary.
Updated: May 6th, 2019
Hi! I have been getting feedback about mast cell tumors and I would like to get some info out there. I will focus on some conventional medicine advances for the time being that should be thoroughly checked into by dog lovers interested in mast cell tumors. These are not general cancer recommendations, rather just a window to full spectrum care, which is a phrase I coined to describe evidence-based selection of cancer fighting weapons from any source. I will focus on Western (allopathic) viewpoints today.
First, the traditional treatment is surgery…get ’em out. I wrote about pre-treatment with Benadryl before surgery, in a previous post, so remind your vet. Have any mass aspirated (needle biopsy) before surgery to diagnose most mast cell tumors so your vet surgeon has a general diagnosis before surgery.
Chemo consists of drugs like prednisolone, vinblastine, and others traditionally. Chemo in dogs is tolerated better than in humans as lower doses are used for cancer. The word “chemo” has a bad ring to it, but this is a prejudice developed from human medicine. Dogs generally handle it better, on the average, although everyone is different.
Note: if you have a Collie or related breed, make sure your vet tests for a MDR-1 gene mutation common in these herding dogs. This genetic issue may increase chances of side effects not only from vinblastine (above), but also vincristine and doxorubicin. Doses of these drugs shoud be lowered significantly if your dog is positive on this test. For more information, see the post on 8/30/08.
Predisolone or prednisone (“pred”, ) are cheap, common, side effects are most often not too bad, and they are tablets so you can change the dose easily depending on your dog’s responses. Vinblastine is a stronger chemo vinca alkaloid chemo agent, more potent than pred, which requires the dog to be in the hospital for injections. Some oncologists like cyclophosphamide and L-asparaginase (you’ll get different opinions and preferences from different oncologists). These are all used for mast cell tumors.
Some stats for Grade 3 mast cell tumors treated with surgery, pred, and vinblastine: At 1 year after surgery, 57% of dogs were still alive, and at 2 years 45% were still alive. Average remission times are about 10 weeks to 5 months with surgery, prednisolone, and vinblastine. Remember, every dog is different, however.
Radiation is used for mast cell tumors that are difficult to remove completely, or any grade 3. This can be high voltage radiation, or brachytherapy, which involves the use of radioactive implants within the tumor site. Yes, a little weird, involved, and costly, but long remissions in the literature.
For more helpful information and tools on Mast Cell Tumors, get a copy of the Dog Cancer Survival Guide
Many are not into invasive care, so take a look below:
One that should be considered for a less intensive protocol is Lomustine or CCNU. This drug has gotten a lot of attention in the last couple of years for good reason. It is a pill,and can be given every 3 weeks. Pretty easy and non-invasive, unlike most chemo protocols, and is a single agent so it is simple. About 40% of dogs with mast cell tumors respond to CCNU all by itself, which is pretty darn good.
Cimetidine should be used in dogs with mast cell tumors, especially those with decreases in appetite or vomiting. This is an antacid which kills two birds with one stone. Mast cell tumors cause excessive acid production in the stomach when they get bad, which cimetidine counters. Additionally, cimetidine has some good anticancer effects that have nothing to do with acid stomach. Finally, it is cheap and easy to get.
Ask your vet about intralesional triamcinolone. They may have not used it before, so do not be surprised, but they can access the info easily (1 mg per cm q 2-3 weeks SQ). It is an simple injection of a form of cortisone that most vets will have sitting on their shelves. It is not very expensive, and very common. Every 2-3 weeks, your vet can inject the mast cell tumor, or infuse the area where the mast cell tumor was removed, with a small dose of this drug. The direct contact of the triamcinolone with any mast cells left in the body will blast them pretty good.
A new drug called SU 111654 (great name eh?) is being worked on at Michegan State University. Looks promising. There is also a technique out there consisting of injecting the mast cell tumor sites with deionized water. Cheap as dirt, but mixed reviews.
This post is just a piece of full spectrum cancer care for mast cell tumors folks. There is a lot more, but I’ll let you sink your teeth into this…
Best to all,
Dr Dressler
Dr. Demian Dressler is internationally recognized as “the dog cancer vet” because of his innovations in the field of dog cancer management, and the popularity of his blog here at Dog Cancer Blog. The owner of South Shore Veterinary Care, a full-service veterinary hospital in Maui, Hawaii, Dr. Dressler studied Animal Physiology and received a Bachelor of Science degree from the University of California at Davis before earning his Doctorate in Veterinary Medicine from Cornell University. After practicing at Killewald Animal Hospital in Amherst, New York, he returned to his home state, Hawaii, to practice at the East Honolulu Pet Hospital before heading home to Maui to open his own hospital. Dr. Dressler consults both dog lovers and veterinary professionals, and is sought after as a speaker on topics ranging from the links between lifestyle choices and disease, nutrition and cancer, and animal ethics. His television appearances include “Ask the Vet” segments on local news programs. He is the author of The Dog Cancer Survival Guide: Full Spectrum Treatments to Optimize Your Dog’s Life Quality and Longevity. He is a member of the American Veterinary Medical Association, the Hawaii Veterinary Medical Association, the American Association of Avian Veterinarians, the National Animal Supplement Council and CORE (Comparative Orthopedic Research Evaluation). He is also an advisory board member for Pacific Primate Sanctuary.
Matt, try to call first. That way they can block off the 15-30 min needed for the biopsy and you can do it in a single trip (recheck first, next biopsy) Don’t forget to fast your dog that morning (you don’t want any surgery done on an empty stomach if possible).
Best,
Dr D
Thanks so much, Dr. Dressler!
I will be heading back to the vet this week to have him looked at again, likely get the biopsy done, and discuss your suggestions. I am also not very far from UC Davis and my pet sitter recommended I tap into that resource as well.
As I get more information, I will return to post the information in hopes of helping others out there.
thanks again…Matt
Hi Matt
Okay, here’s the scoop:
1. All mast cell tumors have the potential to be malignant, although grade 2 and 3 (especially 3) are bad stuff. Grade 1 and only some Grade 2’s have a tendency to be benign, especially grade 1. You can’t diagnose grade on an aspirate. So if you have a little cash, get a biopsy done. Small piece gets send to the lab, no disfiguring, can be done under deep sedation with a little local block of lidocaine, bada bing, there’s the info you need on grade to make a smart decision. Have the DVM give a benadryl inj. first.
2. Your dog is acting fine- great! Problem: once the little one is not acting fine due to mast cell metastasis, you just sealed his fate to a yucky death which can be postponed with some of the stuff I talk about but…so behavior is a JUNK indicator of the severity of the malignant potential of a mass. Sorry, but that is the truth.
3. Please research and discuss with your vet the following for your dog:
Intralesional acemannan injections
Intralesional triamcinolone injections
These are shots right into the tumor which can help it shrink. No disfiguring, can be done under sedation or if the dog is compliant and sturdy, sometimes without even that. There is a ton of other stuff to consider as well (see this thread for some generic suggestions)
Let me know if you need other help.
Thanks!
Dr D
Dr. Dressler,
Please give me some advice. My dachshund was just diagnosed with a mast cell tumor by his anus. I went to a surgeon on the vet\’s advice and she said she wouldn\’t be able to get much of a margin because of its location. And he would possibly be fecally incontinent.
I asked the vet about using prednisone to shrink it some. (it\’s about 1 cm). She said prednisone doesn\’t work well with mast cell tumors. She said surgery is the best option.
Is there any alternative to help him? He\’s healthy otherwise, but this week I see that pooping seems to be harder for him.
What else can be done for this boy? I just lost my other dog recently–she was older and had kidney failure. I\’m not ready to see him go too.
Thank you,
Marcia
Hello, Dr. Dressler
I just learned a couple of days ago that the bump on the muzzle of my 8 year old male dachshund is a mast cell tumor. This was determined after an aspiration taken by our vet. The bump, which as been there for up to a year or so, has recently gotten a little larger and does seem to swell/shrink a bit. This bump is on the upper right side of his muzzle and is now about the size of a dime, but initially was the size of a bug/mosquito bite (about a year ago.) It has not changed size over the past 3 months, give or take. Having read other accounts, this sounds like a slow rate of spread to me.
He is a very healthy dog who joins me regularly for 4+ mile hikes and/or runs in steep terrain and I have observed no other drastic signs or symptoms in his behavior. I have noticed that he has had occasional scratching episodes when no fleas or other skin irritants are present, but these are short lived and not severe ( ie no self mutilation). I understand now this could be related to the release of histamines associated with the tumor. This symptom has been present for about a year or more, but doesn’t occur often. I plan to treat this with 1mg of Benadryl/per 1 lb of body weight if it reappears.
So the vet is telling me that the recommended procedure for this is to remove the tumor, but that it will be very difficult to get good margins. Moreover, she says that my dog may be quite disfigured after the surgery (not just scarred but disfigured!) She also stressed that there are no guarantees that this tumor has not metastasized, which would render the procedure pointless. Moreover, it is not known at this point if the tumor is indeed malignant.
I read on another site that mast cell tumors that have been around several months without significant growth are often benign. What’s your take on that? Part of my dilemma is that I would hate to put my dog through the stress associated with this procedure, and remove part of his nose when it may be unnecessary, or may not even stop the spread of the cancer. And if the tumor is malignant, what kind of quality of life is he going to have after such a procedure? It seems to me that he’s perfectly OK – strong appetite, appropriate weight, good temperament and great stamina, etc, and that has been unchanged over the past year.
I recognize the real challenge here is the location of the tumor and whether or not the entire tumor and margins can be removed. Are there any alternative methods of treatment you might recommend that are less invasive?
Are there any key follow up questions I should ask my vet about his prognosis? Is there more information or data that can be analyzed from lab tests that show the grade or severity of the tumor? What kind of nerve damage or other impact on his olfactory senses could be caused by the procedure?
Based on what information I have, and the signs/symptoms present, I am leaning towards riding this out without surgical removal of the tumor. It just seems like a big gamble for something that might not require such drastic measures or prove ineffective. If I thought that this procedure would cure him, but still leave him disfigured, then I would do it. But that question cannot be answered.
Any help or insight would be greatly appreciated. Thanks for your time.
Thanks for all that wonderful information. I will print and discuss with my vet. I truly appreciate it. Once again you are doing a wonderful service for all of us out here. I look forward to more of your blogs.
Hi Julia,
I am sorry to hear this bad news. Grade 3 MCT are not good. BUT there are some things to consider:
First, consider MDR-1 mutation testing. See the next blog. Rarely a problem in Labs but if you want to be extra extra extra safe get it done.
Second, DEFINITELY discuss cimetidine and triamcinolone acetonide infusions. Print out the blog for dosing. The triamcinolone also can decrease the oral pred requirements.
Third: other things! There is tons of unsound advice out there that has not been really checked out for safety and/or benefit. Here are some things that have:
Ask your vet about ND commercial food, shown to extend life by itself in lympho dogs (without other treatment) by median 6 months, which is solid.
IF No ND, then please research and consider implementation of the following AFTER consulting with your vet or oncologist for precautions (presented for information only but not recommendations for your dog):
a.go low carb, high fat, moderate protein diet. Cancers love carbs. Change foods very slowly by mixing with regular food over 2 weeks to stave off diarrhea.
b.Add fish oil or krill oil (I like krill) up to about 18 caps per day. Introduce slowly and work your way up, also over 2 weeks. Some oncologists don’t like the antioxidants in some of these in the astaxanthin found therein during chemotherapy…a theoretical concern but discuss with your vet.
c. A vitamin supplement, normal doses. DO NOT load up on antioxidants but maintenance antioxidant have been shown to lessen toxicity of chemo without decreasing efficacy.
Regardless of diet, also learn about:
Beta Glucans (see K-9 Immunity), non specific immune stimulator, seems to help with survival times in my experience.
Melatonin, AT NIGHT. Total darkness at night. Anticancer effect documented very well, almost totally ignored in vet med.
EGCG (epigallocatechin gallate) daily (check out Teavigo). Anticancer effect documented, also almost totally unknown in vet med except one rediculous toxicity paper using 200X standard human doses where they killed a bunch of beagles. Disgusting.
Luteolin, multiple documented anticancer effects.
JUVEN, mixed in cottage cheese especially if your dog starts losing weight.
Modified citrus pectin. Antimetastasis effect by receptor blocking documented, also unknown in vet med(okay, you get the idea..)
Curcumin mixed in lecithin for absorption through intestinal wall, start slow, work your way up to full dose over 2 weeks. Can make stool yellow.
Start fresh ginger, 1 teaspoon peeled and chopped, daily in food for nausea and mild immune stim, also mild pro-apoptosis effect in cancer cells.
Direct sunlight, for black dogs about 1-2 hours twice weekly to boost active Vit D3 (don’t bother with oral, can’t get high enough levels), don’t overheat your dog.
Excercise, train, build your dog’s self esteem, stimulate and interact with your dog a lot.
There are gobs of other things but that should get your teeth in something.
Best,
Dr D
My 10 year old lab-mix (has features of a lab mix and vet thinks so, but DNA test says rotterman) was diagnosed with grade 3 MCT in his mouth 7 months ago, no signs of it anywhere else, but could not get enough of tumor to get clean margins with surgery. 6 months of chemo led to clean bill of health. 2 months later, same spot in the mouth the tumor is back, much smaller, but still grade 3. Sounds like radiation is being recommended followed by more chemo. Does this make sense for a large dog who is this old? Will he spend the rest of the time he has left going every week for some treatment or another? If we don’t go there, is there anything else we can do to prolong his life? Our oncologist did not offer any dietary / supplement suggestions. (BTW, prednisone leads to bad incontinence.)
P.S. I am a CU Engineering grad and my husband a CU Engineering MS. I miss the rolling hills far above…
Marcia,
prednisolone is used in mast cell tumor chemo protocols, combined with vinblastine. This is a standard current protocol.
I cannot give recommendations on individual dogs, but:
See above:
intralesional triamcinolone could maybe be an option.
Talk to your vet, maybe a second opinion…
Dr D
Hi Dr. Dressler,
I finally found you! I have been scouring the Internet as well, for information on Grade III Mast Cell Tumors, undifferentiated for my 9 year old black lab. I have read some journal articles and other sites, but I was looking for someone like you who was posting their clinical experience because I do not feel like I get the whole picture from my vet. I also read Lori’s response and commend her on her treatment decisions. Lena’s tumor was found on her left flank, about the size of a silver dollar. The vet did not prophylactically treat her with Benadryl either. The margins came back clear except for one tiny area that was superficial on one lateral border. We had it re-excised to get clear margins, but FedEx lost the sample. I was devastated!!!!!! Her subsequent diagnostic exams have not shown spread to thorax, abdomen, or buffy coat blood smear. But the vet recommended Vinblastine 1.76 mg (she weighs 58 pounds) once a week for four weeks, then every other week for four more treatments, and 40mg of Prednisone for one week and then taper with chemo. She had her first treatment 8/27/08. Now her butt smells like a chemical dump. I am extremely worried about whether I am doing the right thing. She looks like the picture of health as well, great energy, great coat, great appetite. Would you recommend asking my vet about CCNU, cimetidine, and the triamcinolone injections as well? I know the prognosis is horrible, but I did find some research reporting that dogs have survived for quite some time with that Vinblastine/Prednisone treatment protocol. And that they tolerate Vinblastine all right. My husband and I do not have kids, we are both 40, and she really is like one to us. I just started medical school this week and am having a very hard time concentrating on that while I try to figure out the best thing for Lena. Any advice that you could possibly share with me would be much appreciated. And I plan to visit your blog often. Thank you so much for putting this information out there for us. It will make a difference in our pet’s life and many others I believe.
Sincerely, Julia
I think, but am not certain, that our veterinarian described Brandy’s skin growth on her underbelly in very much the same way you did. Even though I know he is an experienced veterinarian… I felt I had to ask him if he had seen anything similar after his close examination prior to surgery. And I was very pleased with his answers although his first educated guess was that it was probably nothing.
I know there are many many wonderful veterinarians out there and I DO include ours as one of them. 🙂
My long post was really to help so many of us know if our “Vet is on the ball.” I now do not know if HAD HE given Brandy a Benadryl injection (just to be safe) prior to surgery — could it have saved her many many more months or years? Something we will never know.
In other words, I guess sometimes it does come down to responsible pet owners to find out as much as they can about ANY conditions. As well as to keep the closest eyes you have on your beloved pet.
Brandy was our first Golden and I remember doing all kinds of Internet research for information on them. Right away I found out that they were more prone to hip dysplasia. But she was not yet two years old yet and I was hoping she would not acquire it. Not so lucky. One morning she tried to get up and walk and she “froze” — scaring us greatly. And THEN finding the diagnosis that she did have it. Very early on.
Cancer was the very last thing we would have been thinking of even during her later years. Yet we had to find out the hard way. *sigh*. I had NEVER come across this type of cancer in all that I have read. But I know now!
A big thanks to you and Rochelle!
And now… OUR household dilemma described in the Omega-3 vs Krill oil thread!
Lori Michaelson
Lori, thanks for the compliment! About your vet: we are all doing the best we can, and we are all human beings with our limitations, including me, you, and your vet. It is really for anyone easy to look back in retrospect and note what could have been done better…BUT..mast cell tumors are known as “The Great Imitators”. They have a variety of looks, sometimes amazingly so. So don’t let the fact that this mass was not diagnosed as a mast cell tumor ruin your confidence in your vet.
Having said that, there are very few vets who are spending the time and energy doing what I am doing. It is not that I am so great or went to Cornell or anything like that…rather I have devoted myself to the area of “outside the box” treatments that withstand a scientific critique, in the hope that we will be able to do better in the future with cancer than we have in the past (rather dismally in conventional medicine). I know it can be done, and I promise I will succeed in this given enough time. It is just a matter of looking and avoiding “condemnation prior to investigation.”
So, there will be inexpensive suggestions and more in this blog, and in upcoming projects. Although I am no longer in your area, you will have access to what I have to offer!
In summary, do not forget all the healing your vet has provided your pets with. I hope the the information in dogcancervet.com and dogcancerblog.com will continue to help both you and your vet help with your dog’s cancer.
Hi Dr. Dressler,
Of course there are many things to consider after such grave diagnosis’. Yet MORE to digest and being aware of. Often times the more options put forth … the more questions become needed. As I described in my post of what supplement is best for dogs with diagnosed mast cell cancers.
Our veterinarian did not suspect mast cell cancer at all so he did not give our dog a Benadryl injection prior to removing the skin growth that we found on our 9 1/2 – 10 -year-old Golden Retriever earlier this month. And, unfortunately, I did not know about you or your blog then or read about doing this. In your other post on mast cell tumors and pre-surgery Benadryl injection you said “Make sure that your Vet is on the ball…”
We have been very happy with the veterinarian that we have been going to for over four years now. He and his colleague have been veterinarians for 25-30 years and he has the bedside manners of an angel and anything we have needed him for … his answers and his logic and his medical explanations have never been disappointing.
But how can someone really know if the Veterinarian they have chosen (or have been pleased with many years) is on the ball with EVERYTHING? This is really a rhetorical question for obvious reasons.
We have had our Golden a little over 6 1/2 years and we had been to 3 other Veterinarians prior to finding our current veterinarian. He was able to help her with a big problem several years ago when everyone else (including ourselves and service dog personnel and the three other veterinarians) were at a loss. But that is another topic/medical problem.
When we went to get our Golden’s stitches removed last week from her recent surgery (removing what was LATER found out to be mast cell tumor – grade 3) I asked him if he had ever heard of giving an injection of Benadryl prior to a surgery on a potential mast cell cancer tumor. It was a chaotic day and neither my husband or I remember his response! He responded right away without hesitation but I can’t remember a thing he said. I have a “feeling” that he MAY have been ‘baffling us with bullsh*t’ but I can’t say for sure now. And, of course, NOW it doesn’t matter as it was not done.
Unfortunately, I think many of us find ourselves in a predicament whereby a certain condition comes up with our beloved pets and THAT is when one finds out if their veterinarian “is totally on the ball.” Unfortunately so. Perhaps that could be another topic — the list of a thousand questions you should ask your veterinarian before choosing him or her as your veterinarian!
The list of potential problems/conditions is ongoing and that poses a problem when it does comes to choosing a veterinarian as well as where someone lives. That is one reason why I like the program MYSTERY DIAGNOSES (for humans) because people find themselves going from doctor to doctor to doctor for years on end before finding the problem. And sometimes the problems the conditions are SO RARE that it may take one doctor in 10,000 that is familiar with THAT certain condition. Been there, done that with myself and “syringomyelia”. Took 4 years for my diagnoses. And a great percentage of those people, including myself, had to diagnose themselves!
The myriad of symptoms also propose a problem and OFTEN throws doctors off. One recent medical condition that I saw on that program was so rare that the blood test to confirm it was only done in another country (I think it was Switzerland)!
So, our veterinarian is very good but NOW, we see, is not perfect. When he called us with the grave diagnosis he also told us that further surgeries or treatments would not help at this point. We most assuredly agree and would not allow further surgeries had he suggested any. And then, many folks like ourselves, do not have thousands of dollars to spend on treatments that may only give her five more months (as an example). Quality of life over quantity of life again. A dog can become a research animal with the best of intentions but certain choices may put the dog through too much and then the dog passes away only months later anyway.
Dr. Dressler … You were very fortunate to be able to go to Cornell. And I am from, and used to live, only about 45 minutes away from there. 🙂 It is one of the best colleges especially for veterinary medicine. And it most definitely sounds like you have more than a vested interest in everything you can find out beyond schooling. But, for the rest of us, how to find more “Dr. Dressler’s” is surely not an easy task!
Thank you,
Lori Michaelson