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.
Great to hear good news!
🙂
D
Marti,
I am sorry to hear this bad news. It is all too common.
please check out the latest blog entries on radiation and the previous one on life quality.
Also do a search on luteolin. Key words luteolin, mast cell stabilization, and cancer, etc. You should look into Lutimax which contains luteolin.
You should be thinking about intralesional triamcinolone, cimetidine, carb restriction, and all the rest of it. Honestly, it would benefit you and yours to just start reading this blog from the beginning….lots to talk about!!
Go Big Red!
Best,
Hi again,
Mystik has been responding extremely well to the pred and has to date only had 2 chemo treatments. She will have 2 weekly checkups at this stage and will continue on daily pred until further notice. I have completely removed processed food from her diet and am feeding her raw. Sourcing raw is somewhat of a mission but here in NZ we do have K9 Natural (raw meat with no grains) and mightymix (raw meat and fats with some grains). Her CBC 10 days ago was great and she had 1 mast cell in the lesion. It was the first time I’d been given numbers so to hear that was just fantastic. Just thought I’d give an update.
Cheers
Nardine
Hi Dr Dressler,
My 21 week old Siberian Husky was diagnosed with grade 3 MCT when she was 17 weeks old. She is currently under the care of Dr Bill Rogers at Massey University Vet Training Hospital here in Palmerston North, New Zealand. Mystik is currently on daily pred and weekly chemo. She is responding extremely well and we are hopeful for a positive outcome for her.
Surgery for Mystik is not an option at this stage due to the location of the tumour. The idea is to shrink it to a size where removal will not cause her disfigurement. The tumour is situated in the part between her nose and top lip.
I have scoured for information and just today came across your website. What a great wealth of knowledge and I thank you for it.
Regards
Nardine
1. There are no studies I am aware of showing that neoplastic mast cells respond to stimulation either by beta glucans or by cimetidine.
2. The medicinal mushrooms as a group tend to protect against side effects of chemotherapy. More specifically cordyceps protects against marrow suppression from cyclophosphamide and nephrotoxicity from other agents. Do a search for cordyceps and colony stimulating factor in the bone marrow and nephrotoxicity. There are also links in the medicinal mushrooms blog you should read.
3. Intralesional triamcinolone is for MCT of the skin/subcutis, not spleen, correct.
4. “Antioxidants” is a huge area and is hugely oversimplified in conventional veterinary thinking. Read the blog post on it, and also the one on ozone for some supplemental info. I will do another one soon to help with people’s general understanding.
Other than that, try to read the blog posts one by one. I have a book coming soon too that tries to do exactly what you are requesting.
D
Dear Dr. Dressler,
I was wondering if you could direct me to where I might find information studies of cimetidine versus famotidine for mast cell tumors if you know of any. It seems like cimetidine would be preferable, but my dog is on famotidine as per oncologist prescription. I asked why, and was told that theoratically cimitidine may have an undesirable immunostimulant action in the case of mast cell tumors. I understand that mast cells are part of the immune system, but it does not seem like cimetidine would necessarily stimulate the mast cells, since it acts on lymphocytes.
There is probably no definite answer, but is stimulating the immune system bad for mast cell disease given that the cancerous mast cells are no longer normal immune system cells anyway? Can you shed some light on this dilemma?
Also, do you know of any studies or other info on the interactions between medicinal mushroom extracts/derivatives and chemotherapy drugs? Or between omega-3\\\’s, antioxidant vitamins and chemotherapy drugs? Or the effects CAM on mast cell tumors? Not being a scientist I don\\\’t know, do compounds that stimulate T cells, as with mushrooms, necessarily stimulate mast cells?
Is there any conventional treatment I\\\’m missing, that I should ask his vets about? I see where you discuss intralesional triamcinolone, maybe that could be done on the inguinal tumor, but it can\\\’t be used in an organ like the spleen, right?
My 11 yr old Lab was recently diagnosed with systematic mast cell disease, after having a small grade 2 removed with clean margins a year ago, there was no other treatment done at that time, regrettably. I guess I thought that if it recurred it would be another localized skin tumor, but now he has an under the skin inguinal tumor, numorous dispersed skin tumors, and spleen involvement. No noticable effect on his daily life yet though. He is getting benadryl, famotidine, prednisone, vinblastine, and lomustine. His current vets (WSU) did not suggest surgery or radiation, I guess because of the locations/ extent. Obviously, bleak even with the chemo since its doesn\\\’t work that well without surgery.
I would like to do complementary supplements, but I don\\\’t know and the vets here do not know for sure what will antagonize the chemo treatments, which I definitely don\\\’t want to do. One has said no problem on the antioxidants, the other says none the day before, day of, or day after the treatments. Neither knows about mushroom compounds except to say that if they stimulate the immune system they could be detrimental. I am having a terrible time trying to find credible studies on the interactions of conventional and complementary medicine, maybe there just aren\\\’t any or maybe I don\\\’t know where to look.
I know I\\\’m basically asking for a mini-course in veterinarian oncology and CAM, but any insight would be appreciated.
Thank you.
Cathy,
Your post requires individualized attention as it is too complex. You can contact me directly. What did your vet say? He or she should be addressing many of these concerns.
D
Dear Dr. Dressler:
My 11 year old mixed breed spay female, Mommy’s Baby, had a lump removed from her left vulvar lip 12 days ago. According to the pathology report, it was one lesion, four months duration, slow growth rate, excised. The biopsy of the mass was the entire specimen 1 x 1x1cm. There was no lymph node involvement. It was rated as a canine mast cell tumor grade 3 with a mitotic index of 1. The mitotic figures are frequent and many atypical. There were no neoplastic cells seen at the surgical margin. (It helps having the report in front of me!)
From what I am reading, I am not encourged by the grade of 3, but can I be encouraged by the fact that it appears when the mass was removed, they were able to take enough to show clean margins?
I can also tell by the report that the cells in the tumor were showing signs of still harboring the cancer.
She is the best dog in the world (to me anyway) and I will try anything to keep her with me longer, but given her age and advancing arthritis, I am also concerned about her quality of life.
She takes Deramaxx, Flaxseed oil, melatonin, Vitamin E, glucosamine and chondroitin plus msm and Proin.
Would the prednisone be a place to start to slow the metastatic rate?
Should I ask my vet about blood work? Would that be a way to tell if it may have spread already?
Since recurrence at the surgery site is common, is there anything in particular I should be looking for?
She is still her happy, hungry self..even loving going to the vet to get her stitches out today and home again being a great big sister to our 3 month old kitten!
Thank you for your time!
The recommended treatment for grade 2 mast cell tumors is wide excision. That means wide margins (a lot of tissue removed…hopefully 1-1.5 inches on all sides approximately. Although the malignant potential of grade 2 MCT’s can be malignant, some are not. Try to get a wide excision done, that, in my opinion, is the best use of your dollars. Get the cells out of the dog.
Oncologists have not researched the information on this blog. It might be illuminating printing the abstracts on the links I provide for his or her review…it can help everyone involved. He/she should almost definitely have heard of cimetidine (as most everyone has…it is Tagamet, a common over the counter med).
I need some help !
My 3 year old Weimaraner had what looked like a wart , to me, about the size of a pencil eraser, on his docked tail. I took him to our country vet and he removed it and I had him biopsy it. It came back MCT grade 2. I had never even heard of this and had no idea how serious this was untill I began researching on the net. My local country vet left me hanging high and dry, with no answers to my questions, nor could he even give me a name of anyone locally to treat this or get any information. The said the closest hospital was about 5 hours away.
I started making phone calls and did find a local clinic that has an internal medicine/oncology vet come in as needed. I met with him and he did a buffy coat and CBC/Chem 12 and everything came back normal. I do not have the money for everything that he suggested, stagging, vinblastine and CCNU.
He recommended doing just the CCNU. I asked him about the intralesional triamcinolone and he said that was only if the tumor was not removed. I asked him about other things that I have read about, such as, Cimetidine, EGCG, Curcumin and he has never heard of these. I’m not getting much reponse about diet either. He told me to keep him on the Iams that he is on now.
I had heard from a gal who works in a vets office ( from a message board that I posted on) and she said that they have had good results with prednisone alone. I asked my vet today about this and he said if you use that in itself that the chemo drugs will not be affective down the road if needed.
I am so confused ! It’s hard for me to even find the CCNU. ( I have to find a pharmacy myself ) I am just so worried I’m not doing what I can for my dog. From what I read, there’s a 40% chance that this won’t spread, but do I take that chance? If I do the CCNU, will it ruin his quality of life, for whatever time he may have ? He has no signs of being ill. Will this drug make him sick or even help him ?
I guess is what I’m asking is….what is my best path to take? Like I said, I am not wealthy and cannot spend thousands. The CCNU and office visits will be over $2,000. That’s all I can do. Have you had success with CCNU alone or does this prolong his life for a few months? Will it make him terribly ill ?
Any advice will be greatly appreciated.
Dear Dr. Dressler,
I see that your expertise is with dogs but I was wondering if you would be able to comment on possible treatments for a cat who recently had surgery for a malignant rectal mast cell tumor (it was just inside the rectum, not far). My cat is an 8 year old male, neutered, domestic mix although possibly half Russian Blue. He’s always been a very active and energetic cat, his diet is both canned (Wellness brand) and dry kibble (Nutro natural). Prior to the discovery of the growth and subsequent surgery, he had no symptoms. The tumor was found incidentally while our regular vet was expressing his anal glands during an routine office visit. He had surgery 4 weeks ago and the pathology came back saying that the growth was a malignant mast cell tumor. (He recovered just fine from the surgery and his back to his old normal self.) We had a consultation with an oncologist vet last week who wants to do an ultrasound, re-tested his blood (all normal, no mast cells floating around) and has suggested radiation therapy or possibly chemo with CCNU (lomustine). My questions are these:
1. Is ultrasound the best diagnostic imaging for small animals to check for other tumors that might be inside or should they be doing an MRI, CT or X-Ray?
2. Assuming no other tumors are found, is radiation therapy the best first choice for this type of tumor, since there was no way they could excise it to clean margins, or would chemo be a better choice? (I can’t imagine getting my cat into the carrier and to their clinic 3x a week for 5 weeks plus subjecting him to anesthesia each time.) I’m not sure how effective radiation would be, plus the possibility that the tissue in that area could become scarred, painful and interfere with proper defecation.
3. Should I adjust his diet to exclude foods with grains?
4. Should I add any supplements such as curcumin, which I had been reading about earlier before I found your site here?
5. Do you know someone who is an expert on this in cats that you could point me to? There is so little information or studies done on visceral MCT’s in cats (especially rectal) it’s very difficult to know what the best course of treatment is
.
Thank you.
Jessica