The Oncologist’s thoughts on mast cell tumors
Sue Ettinger, DVM. Dip. ACVIM (Oncology). Dr. Sue is a boarded veterinary medical cancer specialist. As a Diplomate of the American College of Veterinary Internal Medicine (Oncology), she is one of approximately 400 board-certified veterinary specialists in medical oncology in North America. She is a book author, radio co-host, and an advocate of early cancer detection and raising cancer awareness. Along with Dr. Demian Dressler, Dr. Sue is the co-author of The Dog Cancer Survival Guide: Full Spectrum Treatments to Optimize Your Dog’s Life Quality and Longevity.
Updated: November 22nd, 2018
If ever there was a tumor that fits the saying: “one size does NOT fit all”, it is mast cell tumors (MCT). These tumors are common, particularly skin tumors, in dogs. You may know a dog that had a mast cell tumor removed with surgery and went on to live many happy years to never hear from the MCT again. On the other end of the spectrum, you may know a dog with an aggressive MCT that recurred and/or metastasized quickly and lived just a few months.
What gives? Why is there so much variation in outcome? If your dog has a MCT, will it be a “good” MCT or a “bad” MCT? Can that be predicted? Why is there a new grading system? Do the new c-kit inhibitors (Palladia and Kinavet) work? In my next series of blogs, I hope to answer many questions about the complicated mast cell tumor.
First, let’s understand what MCT are. Normal mast cells are a type of immune system cell and play an important role in inflammation. While other immune system cells tend to circulate throughout the body, mast cells don’t – once they mature, they take up residence in specific tissues. While they can be found anywhere, many live in tissues that mark the boundary between the outside and internal environments; for example, the skin, the mouth, the digestive tract, the nasal passages, and the lungs.
Mast cells hold structures inside their cell walls called granules, which are like little sacks. The granules are filled with substances, or cytokines, including heparin and histamine, which help the immune system respond to problems. Heparin is a blood thinner which helps defend the body against foreign invaders, and histamine is a chemical that triggers inflammation. Normal mast cells release these substances when prompted by the immune system. In addition to their role in inflammation, mast cells are involved in allergies, anaphylaxis (systemic inflammation), the healing of wounds, and defense against outside pathogens.
In this seminar, Dr. Dressler addresses a number of important topics on Mast Cell Tumors, so be sure to get your copy for more information!
Mast cell tumors are cancerous accumulations of mast cells with a malignant potential. MCT is very rarely found in humans, but it is the most common malignant skin tumor in dogs, accounting for 15-20% of all skin tumors. Mast cell tumors first occur in the skin and the subcutaneous tissues beneath the skin. It’s very rare to find MCT in internal organs without a primary skin tumor, but skin tumors can spread to the regional lymph nodes, the spleen, the liver, other places deep in the abdomen, and to the bone marrow.
What causes MCT? Like most tumors, the exact cause is not known. About one-third of dogs have a genetic mutation in a protein called the c-kit oncogene. Unlike skin cancer in humans, which is often associated with sun exposure, studies have found no link between sun exposure and MCT in dogs. But chronic inflammation of the skin may predispose dogs to develop MCT, as can the repeated application of skin irritants.
We also tend to see it more commonly in the following breeds: Boxers, Boston Terriers, Labradors, Golden Retrievers, Pugs, and Staffordshire Bull Terriers. Boxers tend to develop low and intermediate grade tumors.
MCT are one of the most common tumors I see in my oncology practice at the Animal Specialty Center. When should you see an oncologist for MCT? We will pick up there at my next post. In the meantime, remember there is a lot more information about MCT in the Guide.
Get the book to read more on Mast Cell Tumors from an Oncologists Perspective!
Sue Ettinger, DVM. Dip. ACVIM (Oncology). Dr. Sue is a boarded veterinary medical cancer specialist. As a Diplomate of the American College of Veterinary Internal Medicine (Oncology), she is one of approximately 400 board-certified veterinary specialists in medical oncology in North America. She is a book author, radio co-host, and an advocate of early cancer detection and raising cancer awareness. Along with Dr. Demian Dressler, Dr. Sue is the co-author of The Dog Cancer Survival Guide: Full Spectrum Treatments to Optimize Your Dog’s Life Quality and Longevity.
Dr. Ettinger,
I have a 6 yo brindle boxer. She is petite < 50 lbs. She has a mass in her ear and 2 small bumps on her side since she was around 2. The vet told me that they were nothing to worry about. Last wee the tumor in her ear became double the size. Little larger that a quarter. It was red and purple and was oozing/seeping blood and a clear liquid and became irritation. On Tuesday I brought he to the vet and had them remove it. The biopsy came back grade 2 with a mitotic rate of around 1 or 2. It did not have clean margins. The next day her 2 bumps on her side became larger reddish and oozing a clear liquid. I brought her back and they were aspirated. That came back as positive for mast cell. She now seems to have around 8 tumors on her right side. 2 on the left . 3 on her thigh 1 on the shoulder on on neck below her collar 1 on her ankle and the rest are on her trunk spaced between her 2 nipple and an inch from her spine. They are spread across her right side. This is all happening in less that a week and a half. I am going to bring her to an oncologist this week. Do you have some recommendations on what questions I should be asking? For the surgery to take all the tumors would be a lot of skin and the ear would have to go. I red that tumor with lo mitotic rates don't grow fast. I am really confused an d lost.
My wonderful Bischon, Snowball, died on June 24th. He would have been 14 in September. I miss him so much and never have cried so much since my sister died. I never suspected that he had any cancer until it was too late. In looking back, I feel guilty that I may have missed some signs. Maybe you can tell me.
I found a dark little sore on his body that I found when brushing him. If I wasn’t careful, I could scrub the scab off it and it would bleed. My vet said not to be concerned with it and an operation would be far more dangerous. I always checked it and seemed to never grow and never bleed. Much later, he did develop another smaller one on his body.
He would throw up on occasions which the vet and I thought that he had a sensitive stomach. He had some bouts with diarrhea which was corrected with pumpkin mixed in with his food.
He never was sick except a day or two here and there. As I look back, I wonder if some of the things I attributed to growing older was his sickness taking over. He no longer chewed on some of his bones, etc.
It wasn’t until he fell over after one of our walks in early June that I knew something wasn’t right. I thought he had a seizure but found out later on that he passed out. I had him checked over by my vet and was told that he appeared alright but to keep an eye on him. After that episode, Snowball was never the same. He plodded along way behind me on our walks with his tail always down. It broke my heart to see this sudden change in him and he and I knew that something was wrong but we didn’t know what it was. His breathing also seemed not right. The day before Father’s Day while bathing him, I found blood in his ear. I spent Father’s Day at an emergency clinic with him. They found two
growths in his ear and recommended that they be removed, either by them or my vet. I had my vet check him over again and look at his ear. He felt we should monitor it and only remove the growth if it became necessary.
Snowball’s breathing became a real concern to me and by the following Friday, my vet referred me to a cardiologist who also could find no problem with his heart. He suggested an x-ray, which we had done. After examining the x-ray, he gave me the bad news…Snowball had lung cancer. It had metastasized to his lungs from somewhere else in his body. He only lived another two days and died in my arms as I was carrying him in to my vet to be put to sleep.
It haunts me that somehow I missed the signs of cancer in him.
I wonder about those dark spots on his body. Were they cancerous?
I have a 5 year old pit bull mix (shar pei maybe the other half) that I adopted from a family in April that was moving out of state. Turns out that the lumps (3 in all) were MCT graded as II with miotic indexes of less than 1. She has had all three removed and a hermanginoma (which was benign). She was pretty sick after her thrid surgery in 2 weeks so I opted for no chemo but the oncolgy vet has prescribed kinavet. She has had 2 doses and seems to be doing ok with it so far. Do you find kinavet to work but with less side effects than the chemo drug palladia? Will you cover it in your next news letter.
My 7 year old toy poodle had his first mast cell tumor removed from an area between his chest and arm pit last summer (July, 2011). It was a Grade II, low. The biopsy report indicated that he needed surgery to get clean margins. I also did a blood panel and everything came back negative which was just great. Then six months later, he developed another mast cell between his back and neck. It was a grade II, low. I found it when it was very small. I was surprised because he had all negative results on his blood panel. My vet called an oncologist at the AMC again. She said that some dogs are just little “mast cell factories.” Since the margins were clean on the biosy nothing more according the oncologist needed to be done other than being extremely vigilant about checking his skin. About a week ago I discovered another – the smallest thing my vet said she had ever removed. It came back a Grade 1 with clean margins, hence nothing more had to be done. Since my dog is groomed regularly, I find that he comes back itchy and wonder if I should have the groomer use a special shampoo, although we have tried oatmeal and others, could you recommend something else. Also he tends to get red spots on his tummy when he lies on the grass; then they go away. Obviously, he has a very allergic skin. I adore this poodle with all my heart and soul! Is there anything else you feel I should be doing? I want him around for a long time – he is my little boy!!
I bought your book after Edward had the first mast cell and am very much looking forward to all your future blogs!! What else can I do for my little boy? I was cooking special meals for him but he got pancreatitis and now has to be on a strict Hill’s diet of I/D. I am not crazy about Hill’s prescription diets, but what can I do?
Hi Johanna,
unfortunately some dogs go make multiple MCT. I am glad he is under the care of an oncologist.
I really like the Apocaps supplement for dogs with MCT, if not on steroids or NSAIDs. Keep reading the book. Dr D has lots of good advice on supplements in there!
All my best,
Dr Sue
I have a big (not fat) 150 pound American Bulldog who is 6 1/2 yrs old diagnosed with Mast Cell Neoplasia. The vet insisted on 4 biopsies that he needled aspirated & charged $500. He next came back with a minimum estimate of $6000 to remove 2 tumors that were cancerous. He further wanted me agree to the removal of the dogs leg if he thought it necessary for an additional $3000 and he made it pretty clear he would think it necessary. He then said chemo would be an additonal $3500. Further he said the dog would probably need additional surgery every six months for returning tumors. He was the only vet I found willing to operate on a dog this large. I am on disability raising a 4 yr old grandchild. The doctor told me if I didn’t operate the dog would die shortly. This was far beyond anything I could afford. As a retired nurse I questioned this almost immediate death sentence. The dog had one swelling the size of a peach pit and another the size of a pea that tested cancerous, all sitting on the skin surface, with no redness or broken skin. The dog is active and I cart with him. If it wasn’t for the tumor swelling I would not know anything was wrong. There is no way I could assist a 3 legged 150 lb animal to go defecate as I have impaired balance myself. I contacted several bully breeders who directed me to your website. THANK GOD! I have him on Cimetidine 500mg and Benadryl 50mg BID for one week and today I noticed the smaller tumor was barely noticeable and the larger one was shrinking. He has no other symptoms. If the tumor is still visible after 3 wks should I continue with the Cimetidine and Tagamet until it is no longer visible? One breeder suggested even if the tumor disappeared, I should give my dog this treatment every six months to prevent a reoccurence. (Said it made the remissions last longer). I am an organic vegetable gardener, and he loves the cancer diet. I am hopeful with the diet, supplements and OTC chemo, the dog will be able to live out his normal life span which I am told is 8-9 yrs because of his excessive size. Thank you very much and God Bless for the work you do.
Hi Joan,
I am sorry about your dog. This is a complicated case and I cannot really make specific comments with the medical records and an examination, because I could be missing important info and make recommendations that are not specific to his case.
I am glad you found the site, and I would encourage you to read the chapter on MCT in the book. Cimetidine and Benadryl are addressing the substances release by the cancer cells, but they do not kill the cancer cells the way chemo does. So he may need to be on those for awhile. If you were not happy with your vet, trying seeing another who can help guide you with his meds. If surgery is not an option, chemotherapy for multiple MCT is an option.
All my best, Dr Sue
My 11 year old Border Collie was diagnosed with squamous cell carcinoma May 31, 2012. While having his teeth cleaned they found a mass on his tonsils and called me to approve a biopsy. The vet was only able to tell me it’s a fast spreading aggressive cancer and gave him 3 months to live. He also said chemo or radiation might prolong his life but only by a few months and the quality of life he would have would have would not be worth having the treatments.
I went online and ordered your amazing book and have had the pleasure of talking to someone on the “hotline” twice. The book doesn’t say much about the type of cancer my dog has nor did the vet give me any advice except for 3 months left. I’ve been following the diet to the T, and have stocked up on Apocaps, K-9 Immunity Plus (I called the manufacturer and they have since removed the sugar), digestive enzymes and everything recommended in the book. Is there any advice you could pass on other than the 3 months the vet gave for my dog to live?
In Gratitude,
Pamela Marentis
Pamela,
I am so sorry about your dog. Tonsilar SCC is mentioned in the oral tumors chapter, but there was not space in the book to cover it all.
Overall they are uncommon in dogs, they can be aggressive, but treatment can be considered, and I have seen successes when they are caught early and treated aggressively. Have you considered a 2nd opinion with an oncologist?
Other than that, it sound like you are covering your other bases as recommended in the book. Good luck!
All my best, Dr Sue
Pamela,
Sorry to hear about your Border Collie. Tonsillar SCC is an aggressive tumor, but uncommon. I believe I mention it briefly in the oral tumor chapters. I personally have had some dogs do well with combined surgery, radiation and chemo, so it may be something to consider. I would encourage you to consult with an oncologist for more specific recommendations as it is impossible for me to do that appropriately through this blog. It’s great you have the book and the supplements. Good luck!
All my best, Dr Sue
Please write some information on Hemangiosarcoma. What are your thoughts
about metronomic therapy after four sessions of doxirubicin? I am confused
and would like some clarification. What is the prognosis once it is
diagnosed.
Jeannette,
I think metronomic after IV doxorubicin is a good idea, but I personally give 6 IV doses before switching. Prognosis for hemangiosarcom varies based on location (spleen, heart, muscle, subcutaneous, skin). Sorry you are confused. Have you read the chapter in the Guide?
All my best, Dr Sue
Our Boxer, Spike has had a MCT Grade III removed twice. He is now four years old. He has been on Kinavet for a year now with no recurrence of the tumor. I am very interested in reading your thoughts on the drug and MCT in general. Thank you for your newsletter! Elaine
Elaine,
Thanks for reading! I have a few more posts planned on MCT so stay tuned. =) I do cover Kinavet and Palladia, both c-kit inhibitors, in the Guide too. Love to hear that spike is doing so well!
All my best, Dr Sue
Very interresting! I lost a dog to mastcel cancer, he was a Shar Pei, had skin problems all his life. Primary tumor was never found, tumor was in his lymph (on the side and leg behind). Masivet (in VS called Kinavet) did not help.
I see more and more Shar Peis dying in these last few years. Also at young ages!
Esther,
Thanks for your comments. Some MCT can be very aggressive. Sorry for your loss.
All my best, Dr Sue
My 7yr springer has had a grade 3 tumour removed & has had an ultrasound, aspirates etc no spread was detected thankfully, she is undergoing radiotherapy & chemo to kill off any remaining cells, my question is once treatment is over & she has recovered can she have vaccinations? we are in the uk & our kennels here do not accept titre test result certificates, I keep reading about vaccinations bringing back cancer but I don’t know if these are just scare stories or if there is some truth in them?