Among the most common cancers in companion animals, mast cell tumors respond well to lifestyle changes and complementary therapies, from vitamins to herbs to medicinal mushrooms.
No one wants to hear that their dog or cat has a mast cell tumor. Unfortunately, this type of cancer is the most common malignant skin tumor in dogs and the second most common in cats. Mast cell tumors are usually found in middle-aged animals, but can occur at any age. On the plus side, treatment options are improving the prognosis for these malignancies, and complementary therapies can be very beneficial.
How the Disease Differs Between Dogs and Cats
Dogs
Boxers and Boston terriers make up about 50% of all canine cases of mast cell tumors; other dog breeds commonly affected include pugs, bull mastiffs, cocker spaniels, bull terriers, fox terriers, Staffordshire terriers, golden and Labrador retrievers, bulldogs, beagles, Schnauzers and Weimaraners. In dogs, mast cell tumors are most often found on the trunk of the body, followed by the limbs, and are less likely to be found on the head and neck. Those located on the limbs, head, and neck are more likely to have a favorable prognosis than those found on the trunk or groin.
Cats
Siamese cats are the breed most commonly associated with the development of mast cell tumors. The tumors are most often found on the head and neck, followed by the extremities. Lesions on the head and neck are less aggressive than those on the extremities, and may spontaneously regress.
Note: Mast cell disease of the internal organs can also occur; this is a more aggressive form which is often preceded by tumors on the skin. Animals with internal mast cell cancer may show loss of appetite, vomiting, lethargy, bloody vomit or stools, and lymph node enlargement.
Diagnosis and Staging
Once a mast cell tumor is diagnosed using cytology (looking at cells under the microscope), the stage of disease must be determined. Full-body imaging (radiographs, ultrasound, CT
scan) may be done to look for spread to other organs. Surgical removal of the tumor is recommended if it’s in an area where clear margins are obtainable. The tumor is removed and submitted for microscopic analysis and grading.
Tumors submitted for biopsy will be graded I, II or III, or may be reported as either low- or high-grade tumors. Unfortunately, histologic assessment is prone to operator subjectivity, giving rise to extremely variable grading results for the same tumor among different pathologists.
Note: In one study that involved ten pathologists evaluating the same tumors, only four of 60 malignancies were given the same grade by all ten pathologists. The low- or high-grade scheme has less variability and more predictability for prognosis.
Conventional Treatments
Low-grade or Grade I tumors are less likely to reoccur or spread to other sites, whereas high-grade or Grade III tumors are more aggressive and may warrant aggressive treatment such as chemotherapy or radiation. Chemotherapy efficacy can be low, however, and is most often used to limit regrowth of an incompletely removed tumor, or in cases of metastasis or primary tumors in internal organs. Less than 20% of all mast cell tumor cases are Grade 3. Dogs with multiple skin mast cell tumors may not have a worse prognosis than a dog with only one, if they are all low-grade.
Traditional treatments for mast cell tumors include the use of antihistamines (diphenhydramine/Benadryl), antacids (famotidine/Pepcid or omeprazole/Prilosec), and corticosteroids (prednisone). Side effects can include increased or decreased appetite, increased thirst and urination, kidney and liver damage, and gastrointestinal ulceration, making long-term use of these medications undesirable.
Complementary Therapies
Complementary therapies can be extremely beneficial for treating dogs and cats with mast cell tumors. The goal is to decrease the inflammation and histamine release within the body. The following regimen, implemented under the guidance of a holistic or integrative 
vet, includes lifestyle changes as well as alternative treatment options.
- Decrease stress in your dog or cat’s life – this includes dealing with any anxiety, boredom, or frustration.
- Your animal’s diet should be hypoallergenic and low in carbohydrates. For many dogs and cats, this may mean avoiding chicken or beef. From a TCVM (Traditional Chinese Veterinary Medicine) perspective, pork, rabbit, duck, or cold-water fish would be good protein choices.
- Quercetin is considered nature’s Benadryl; it can be combined with nettles and bromelain to decrease itching and histamine release.
- Probiotics can help restore the skin and gut microbiome to decrease inflammation and improve the immune system.
- Cannabidiol (CBD oil) can help reduce inflammation and support a healthy immune system.
- Plant sterols are natural steroids, and can be used in place of prednisone in most cases. Phytosterols suppress the release of Interleukin 4 (IL-4) so histamine is not released.
- Beta-glucans found in mushrooms help regulate the inflammatory response, inhibit tumor growth and spread, and induce cancer cell death (apoptosis). Medicinal mushrooms include Cordyceps, Shiitake, Maitake, Reishi, Chaga, and Turkey Tail.
- The Chinese herbal formula Xue Fu Zhu Yu Tang (Stasis in the Mansion of the Blood) contains ten herbs; it promotes blood flow to the skin, bringing immune cells that can destroy cancer cells. This formula can be given orally and used topically in a paste with vitamin E or aloe.
- Turmeric helps move blood and has anti-cancer effects. Combining turmeric with black pepper and a fat will help with absorption.
- Antioxidant and cancer-fighting herbs that can be added to the diet include basil and ginger.
- Omega-3 fatty acids can help reduce inflammation. Options include fish oil, phytoplankton, algae oil, calamari oil, and krill oil.
- Have your animal’s vitamin D levels tested. Most dogs and cats with cancer have low vitamin D levels. This vitamin has been proven to have anticancer effects.
- Vitamin A is a powerful antioxidant and is found in broccoli, spinach, carrots, eggs, mushrooms, and fish.
Note: Avoid over-stimulating your animal’s immune system. Most holistic veterinarians will recommend that dogs and cats diagnosed with mast cell cancer no longer receive vaccinations. Also avoid pesticides and synthetic ingredients in pet food, and make sure he gets plenty of exercise to support his emotional well-being.
Having your dog or cat diagnosed with a mast cell tumor is frightening, but a holistic or integrative approach to his treatment will help improve his prognosis and quality of life, and keep him with you longer.
