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Mast cell tumor life expectancy in dogs depends on many things.

Mast Cell Tumor Dog Life Expectancy

The life expectancy of a dog with a mast cell tumor depends on the stage and grade of the tumor, the location, treatment options chosen, the particular strain of mast cell tumor and the overall health of the dog.

Most mast cell tumors can be treated with surgical removal without a recurrence.

It’s important to note that very aggressive tumors (considered Grade 3) are also the least common.

The life expectancy of a dog with an aggressive tumor that has spread to other parts of the body (mediatized) is roughly 4 to 6 months.

Assuming the mast cell is in a place where it can be completely removed through surgery (including a wide margin to account for cancer cells not seen) *there is a 90 – 100% chance the tumor will not recur.

[*Source: Long Island Veterinarian Specialists]

Quick Diagnosis is Key to Life Expectancy

Diagnosing mast cell tumors in dogs quickly is essential for a good prognosis. The first step is to obtain a fine-needle aspiration which will help determine whether the mass is cancerous or not.

Fine-needle aspirations and biopsies are two different things.

The fine-needle aspirate involves inserting a needle into the mass and withdrawing cells for examination. A biopsy, however, involves the removal of a small piece of mass for microscopic examination.

The following diagnostic tools may or may not all be necessary. There are a series of steps taken to make an accurate diagnosis.

If the tumor is believe to be benign, testing might stop at the fine-needle aspiration stage. If there is concern that the tumor is cancerous and may have spread, more elaborate testing may be required.

Blood Test

A blood test should be conducted to obtain a complete white blood cell count. A serum chemistry panel and urinalysis help to determine the dog’s overall health condition.

If underlying conditions are diagnosed it can affect the type of treatment options chosen and could affect the dog’s overall life expectancy.


A piece of the tissue is drawn out with a very fine needle and that tissue is examined under a microscope.

The importance of the biopsy is to establish grading of the tumor. Grading of tumors is generally done by a pathologist.

Grade 1

Typically benign or non-cancerous.

Grade 2

There is a possibility that the tumor is cancerous and may invade nearby skin tissue.

Grade 3

Grade III tumors represents a more aggressive tumor likely to have spread to other parts of the body.

Staging is another step that identifies the extent to which the tumor has spread (or not).

Lymph Node Examination

The veterinarian might feel for enlarged lymph nodes close to the mast cell tumor site. 

The examination is painless and can give the doctor a better sense of whether the cancer has spread. If the lymph nodes are enlarged, a local lymph node aspiration may be conducted.

When tumors are found in areas that make it difficult to remove completely through surgery, more tests might be required.

The additional tests help to determine what the treatment options should be.

Abdominal Ultrasound (Sonograph)

Ultrasounds use sound waves to create images of organs within the body. Abdominal ultrasounds are another way to help determine whether cancer has spread to the liver, spleen, and lymph nodes located in the abdomen.


Although radiographs are not entirely helpful in determining the spread of mast cell tumors, they can be useful if there are other underlying conditions present.

Bone Marrow Aspiration

Bone marrow aspiration in dogs involves administering a sedative along with local anesthesia. A needle is then inserted into the bone marrow to remove cells for microscopic examination.

A bone marrow biopsy is more involved and requires general anesthesia. A veterinary surgeon then removes what’s known as a “core sample” of the bone marrow.

Not every dog will require this diagnostic tool.

Mast cell tumor dog life expectancy varies depending on the stage of the cancer.

Mast Cell Tumors Symptoms In Dogs

It’s common for dogs to develop lumps and bumps, especially as they age. Unfortunately, it’s impossible to determine whether a lump is cancerous or not just by looking at it.

Unfortunately, mast cell tumors are complicated and may or may not involve the presence of the following signs:

  • Lumps that randomly increase and/or decrease in size
  • Swollen lymph nodes
  • Loss of appetite (inappetence)
  • Welts on the skin
  • Vomiting
  • Weight Loss
  • Bloody or black stool
  • Pain in the abdomen

Top Treatment of Canine Mast Cell Tumors

The first line of treatment for dogs with mast cell tumors is surgery. The goal is to completely remove the tumor by including a safety margin of 1 inch around the site.

This is performed to ensure that any cancer cells that have migrated into the surrounding skin tissue is removed.

After the initial surgery, the tumor is examined to determine whether it is benign or cancerous and whether it has spread.

If it is cancerous and thought to have spread, further treatment options include:


Radiation therapy helps to permanently destroy any microscopic cancer cells.


Chemotherapy is an option for dogs who have aggressive mast cell tumors thought to have spread to the lymph nodes and organs.

It’s also used for dogs with multiple mast cell tumors occurring at the same time.

Chemotherapy stops cancer cells from dividing and can help reduce the size of a tumor prior to surgery.

Targeted chemotherapy using drugs like Palladia (toceranib) or Kinavet (masitinib) work to slow down the progression of mast cell tumors in dogs.


Prednisone is used in combination with other treatment options and may be useful in shrinking the size of the tumors.

In some cases, it may even create a temporary remission.


Antihistamines help stabilize mast cell tumors in dogs by de-activating excessive histamine release.

Common Side-Effects of Chemotherapy

Dogs typically receive lower doses of chemotherapy than humans. As a result, the side-effects tend to be milder.

Dogs do not lose their fur as a result of chemotherapy, although they may experience appetite loss, vomiting or diarrhea.

Dogs tend to respond very well to chemotherapy with few side-effects. However, if you notice anything unusual or ongoing, be sure to discuss with the veterinarian or veterinarian oncologist.


Remember that most mast cell tumors can be completely removed through surgery and often do not recur or spread.

It’s important, however, to be aware of any new lumps and bumps on your dog. Mast cell tumors are common in dogs over the age of 8, although they have occurred in puppies.

Posting a photograph of the lump on social media is not a substitute for veterinarian care.

Nobody can diagnose a mast cell tumor by appearance alone. Unfortunately, these tumors can look like any number of things. Getting an early diagnosis with treatment offers your dog the best prognosis for long-term life expectancy.


TMS The Mast Cell Disease Society, Inc.

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9 thoughts on “Mast Cell Tumor Dog Life Expectancy”

  1. Thank you. This article was very helpful to me as my dog was just diagnosed with MCT. THANK YOU! Jamie

  2. We have a very precious Shih Tzu who just had surgery yesterday for mast cell. We found it in July and tried prednisone. Our vet ad used us to remove it. She is recovering nicely today. As with any surgery, it was hard on her. But she actually wagged her tail today. Mom is having a problem with the diagnosis and I can’t seem to stop crying. It gave me great comfort to read your article and all the information. We are waiting for the biopsy report but you have raised my expectations. Thank you for your research.

  3. We have a 10 year old American Staffordshire who had a suspicious lump on her abdomen. The dog did not seem bothered when I felt it. The vet thought it maybe a mammary cancer even though she was spayed at 6months. Given her age we decided to have the lump removed rather than have a biopsy and then subsequent surgery. The vet successfully removed the lump and pathology results revealed it was a stage II MCT. Vet removed enough tissue and the margins were clean. Dog has recovered well.

  4. I have a 9 year old French Bulldog that was diagnosed with agressive
    stage 2 MCT nearly three ago. He had surgical removal of single tumor on abdominin. After initial surgery and staging I decided to see a Vet Oncologist and get opinion. He recomennded second surgery to get wider margins. A local Vet he recomended performed the resect at half the Oncologist price. Happy to report that this boy is doing great three years post op now. I also researched the use of the spice Turmeric and have given my boy a 400 mg capsule of it daily since surgery along with an antacid and Cimitidine that you can get cheap off the shelf at store( research dose). Ive read of the anti cancer benefits of these products in Suzanne Summers book Knockout when my Mom was diagnosed with cancer. Dont know if its helped but he is still here dispite the grim outlook we were given three years ago of 2 to 4 months without surgery and 12 to 15 months best case with surgery. I would recommend anyone faced wifh this difficult prognosis with their pet to consult with a Vet Oncologist before doing anything and to research these other supplements that can retard MCT process. For those with deep pockets I was impressed with what I read about the herb nick named “Turkey Tail”. It was pretty expensive but had some impressive studies. I opted for Turmeric after reading some testimonials from some pet owners in our situation. I have unfortunately just began another angjishing journey with this disease. My 14 year old female Frenchie just yesterday diagnosed with MCT on her ear, looks agressive, pending surgery. I know, I know shes 14 but she still so full of life I have to give her a chance.

  5. I also want to note that I found a web site for PENN VET, a vet hospital college in Pa. It was a wonderful educator about this disease!!!

  6. I have a 5 yo Boston Terrier female, Ruby, that was diagnosed with stage II MCT in July of this year. The tumor was removed on July 27, 2018 and 4 weeks later, I have discovered another growth that has been dx’d as the same by needle biopsy. I am very pleased to hear about turmeric and Cimitidine. I will give that a try. I don’t want to put her through aggressive treatments, just to prolong her life for 6-12 months. It is extremely difficult, but I am working on acceptance of the diagnosis. I will love this very special baby girl because she deserves it!

  7. I am taking my dachshund in to the vet today to have what I believe is a MCT on his neck looked at. It was just a small warty looking thing smaller than a pea a month ago now it has grown to the size of a quarter. ☹️ He’s almost 13 years old. He’s still pretty spunky for 13 years old. Hoping for a good outcome.

  8. Hi Sherry (is it Sherry?) I’m sorry because I believe I called you Brian in a previous response. It sounds like you’ve been through a lot with your dogs. I highly agree to consult with a vet oncologist. That’s the person with all of the answers and best suggestions.

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