Mast Cell Tumors in Dogs

Mast cells are the cell type in skin responsible for allergic reactions (itching, swelling, redness). Mast cell tumors are the most common skin cancer in dogs. There are three grades of canine mast cell tumor, determined through histopathology (biopsy), which predict tumor behavior:

Grade I mast cell tumors are considered well-differentiated. Metastasis is rare and local therapy, surgery with or without radiation therapy, is the treatment of choice. 85-95% of dogs with aggressive surgery or radiation therapy have local control 2 years after treatment.
Grade II mast cell tumors are intermediate grade. Although metastasis is uncommon, they tend to be more locally aggressive than grade I mast cell tumors. They have a higher rate of recurrence after surgery compared to grade I.
Grade III mast cell tumors are poorly differentiated. Metastasis to lymph nodes, liver, and spleen is common. Both local therapy (surgery and radiation therapy) as well as systemic therapy, chemotherapy, is recommended. Once metastasis has occurred, most dogs have a good quality of life for 1-2 months with no treatment or no response to treatment. With a good response to chemotherapy (such as Vinblastine, Lomustine, both have a 50% response rate) this can be extended to 6-9 months, sometimes up to 1 year.
- The goal of chemotherapy is to extend quality of life. Therefore, it is important to us that side effects are absent to minimal (this is very different compared to chemotherapy in people, where side effects like nausea, weight loss, and hair loss are common).

Dogs that have one mast cell tumor are at higher risk for development of other mast cell tumors in the future, so physical examinations and cell samples of new masses are an important part of future care.

For further information and treatment options, have your veterinarian refer you to a board certified veterinary oncologist, who can discuss specific treatment options for your pet.

Back to top

Medical Services + Our Doctors + About Us
Cancer Survivors + Pet Tributes + Contact Us
Location + Home + Sitemap

Veterinary Specialists of North Texas & Animal Cancer Center
12101 Greenville Ave., Suite 114
Dallas, TX, 75243
972.437.9499

OFFICE HOURS: Monday-Friday 7 am - 6 pm By Appointment Only

OUR DOCTORS: Cheryl K. Harris, DVM, ACVIM Philip L. Treuil, DVM, MS, ACVR Héctor J. Encarnación, DVM Christine Rees, DVM, ACVD

Mast Cell Tumors in Dogs

OFFICE HOURS:

Monday-Friday
7 am - 6 pm
By
Appointment Only

OUR DOCTORS:

Cheryl K. Harris,
DVM, ACVIM

Philip L. Treuil,
DVM, MS, ACVR

Héctor J. Encarnación,
DVM

Christine Rees,
DVM, ACVD