Mast Cell Tumors in Dogs-- What You Need To Know

 

 

WHAT ARE MAST CELL TUMORS?

Mast cell tumors are a common tumor type for dogs, especially in Pit Bulls, Retriever,  Shepherd, and other large breeds.  They are less common in cats.

Mast cells are one of the cell types involved in the immune system, in particular the mediation of allergies and sensitivities.  Thus it makes sense that the breeds mentioned above are the most commonly affected, since they are breeds which are known for their allergic problems.

 

HOW ARE MAST CELL TUMORS DIAGNOSED?

In general, early mast cell tumors appear as simple thickening of the skin, rather than as more prominent “lumps” like lipomas create.  This makes their early diagnosis very difficult. 

Once we find a suspicious bump, the best way to make a diagnosis is to do a “fine needle aspirate”, where we stick a small needle into the mass and aspirate, or suck back, some of the cells within the bump.  We then look at those cells under the microscope, and mast cells have a very characteristic appearance.  If there is any question, we always recommend sending the microscope slide off for histopathologic exam by a pathology specialist.

 

WHAT'S THE BEST TREATMENT FOR MAST CELL TUMORS?

Once diagnosed, the primary form of treatment for mast cell tumors is their surgical removal.  Because they have a tendency to develop roots, we always try to get a margin of at least one centimeter—and preferably two—both around and under the mass. 

The early excision of these masses is very important when you realize that they have a tendency to spread to distant sites via the bloodstream or lymphatic vessels.  Thus the bumps you and we feel on the skin may not be the only ones your pet has, and the longer they are in place before surgical removal the higher the likelihood of internal spread becomes.  Regional lymph nodes and the spleen are common sites of metastasis.

 

STELFONTA FOR MAST CELL TUMORS IN DOGS

Introduced about 3 years ago, Stelfonta is a brand new and non-surgical approach to treating mast cell tumors in dogs.  Stelfonta is injected directly into mast cell tumors and essentially kills them without need for a scalpel blade.  However, as the tumor is killed it leaves a hole in your pet's skin, which can look a little tough for a couple days but heals very quickly.  For this reason, Stelfonta can only be used on a pet's sides, lower abdomen, or legs to insure good drainage from the post-surgical wound.

 

PALLADIA FOR MAST CELL TUMORS IN DOGS

Palladia is an oral tablet that was specifically developed to fight Mast Cell Tumors that could not be surgically removed for some reason -- generally size or location.  It's not cheap, but the biggest issue with Palladia is that about half of patients run into GI problems like vomiting or diarrhea while they are on the drug.  

Palladia is now being used as adjunct therapy for a number of different tumor types, in addition to mast cell tumors. 

 

IMMUNOTHERAPY FOR MAST CELL TUMORS IN DOGS

Perhaps the most exciting development is that we in veterinary medicine now have access to the same immunotherapy used in advanced human cancer treatment.  Basically this involves a) the surgical removal of at least part of the tumor, b) sending it off to a specialized lab, where they will c) develop an injectable vaccine SPECIFICALLY against your dog’s tumor.  This enables us to use your dog’s own immune system to fight their cancer.

If you're thinking of using a cancer vaccine in your pet's journey, PLEASE talk to your vet prior to the biopsy process as they may need to process the sample a little differently.

Another approach is used by FidoCure, who uses a biopsy sample from your pet's mast cell tumor to test the cancer for genetic markers which may enable the use of human checkpoint inhibitor drugs given orally by you at home.

 

NATURAL TREATMENT OF MAST CELL TUMORS

From an integrative approach, our goal with mast cell tumors  is to mellow your pet's immune system.  We do this by...

  • avoiding or aggressively treating allergies,
  • minimize inflammatory disease like dental problems or arthritis, and
  • by minimizing vaccines, as vaccines are designed to STIMULATE the immune system and that is the last thing we need.

Secondly, we can use natural supplements to help reduce inflammation throughout the body.  Here are the best natural supplements for reducing inflammation in our pets:

 

HOW ELSE CAN I HELP MY DOG WITH MAST CELL TUMORS?

Because mast cells are a normal part of allergic responses, as mast cell tumors develop we may see signs of allergies develop—itchy skin or GI symptoms like vomiting or diarrhea.  For this reason, it is never a bad idea to begin a mast cell tumor patient on simple antihistamines like Benadryl (dosed at 2 mg per lb body weight 2x a day) or Zyrtec (1 mg per lb body weight once a day), and Pepcid AC or Prilosec (1 mg per lb body weight once daily)  to protect the stomach.

 

 WHAT'S MY PET'S PROGNOSIS WITH MAST CELL TUMORS?

It is important that you understand that once a pet begins developing mast cell tumors, it is very likely that you will see others develop in the future.  For this reason, we recommend weekly “massages” of your pet in an effort to detect other tumors as early as possible.

Once excised, we always recommend the histopathologic exam of your pet’s tumor for staging purposes.   Mast cell tumors are typically graded on the Patnaik scale from 1- 3.  The lower the number, the less aggressive such masses are.  The higher the grade, the more likely we are to see recurrence and/or metastasis.

 

And here's the biggest point of all.  We're here to help you, so just let me know if you need a hand.