Cancer in dogs

Mast Cell Tumor 101

A cancer diagnosis for your dog can feel overwhelming. Of course, you’ll want to get your dog the treatment they need so they can return to their normal self as soon as possible; but where do you start? Let’s start by learning about what your dog is facing.

What is a mast cell tumor?

Mast cell tumors (MCTs) are the most common type of skin cancer in dogs.1-4 Mast cells are a normal part of your dog’s immune system and are found naturally in most of their tissues and organs, including the skin. When healthy, mast cells are beneficial, helping dogs with allergies and inflammation. But when these cells turn cancerous, a mast cell tumor, or lump, forms. It’s important to get any lumps checked by your veterinarian who will determine if they are not harmful (benign) or need to be removed before they spread throughout your dog’s body (malignant).
Mast cell image under microscope
Mast Cell

A tumor, a cyst or a lipoma? Benign or cancerous?

Like our pups, no two mast cell tumors look and behave exactly the same. MCTs may be ulcerated or smooth, skin-colored or have a reddish tone, and hairless or completely covered in hair. Some grow slowly and others change rapidly in size and appearance. Because mast cell tumors are not easy for pet parents to identify, often looking like a benign cyst, it’s important to bring any lumps to your veterinarian’s attention as soon as possible.

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Tumor pictures

What is the life expectancy for dogs with a mast cell tumor?

The prognosis for every dog with mast cell tumor disease is different.  Dogs with low-grade tumors can often lead a normal life after successful removal of the tumor. However, for dogs with high-grade tumors, there’s a heightened risk of cancer spreading to other organs, posing greater challenges for treatment. Veterinary evaluation and ongoing monitoring will be crucial for assessing your dog’s prognosis and tailoring an effective treatment plan.

About STELFONTA
MCT treatment options

Tumor grade vs tumor stage? What do they mean?

Canine mast cell tumors are classified by grade and stage. This helps your veterinarian decide how to best treat your dog.

Tumor GRADE:

Likelihood of spreading.

Understanding the grade of mast cell tumors is crucial as it signifies their propensity to spread and recur. Two classification systems are utilized for this purpose:

1. Patnaik System: Grade 1 tumors are less likely to spread, while Grade 3 tumors pose the highest risk of spreading and recurring.

2. Kiupel System: This system categorizes tumors into either Low or High grade, providing insight into their potential behavior.

Tumor STAGE:

In the context of mast cell tumors “stage” refers to the extent the cancer has spread within the body.

Staging helps veterinarians determine the severity of the cancer and plan appropriate treatment. It considers factors such as tumor size, lymph node involvement, and presence of metastasis.

Understanding the stage is crucial for devising an effective treatment strategy and predicting the prognosis.

Do mast cell tumors only affect certain breeds?

While any dog can get a canine mast cell tumor, they occur most often in older dogs and certain breeds.

Breeds at increased risk for mast cell tumors:5

  • Boxers
  • Bull Terriers
  • Boston Terriers
  • Pugs
  • English Bulldogs
  • Labradors
  • Golden Retrievers
STELFONTA-Mast-Cell-Tumor-page-dogs-age
Most MCTs are diagnosed in dogs between 7.5 to 9 years old2
Dog breeds that get mast cell tumors
Breeds that get mast cell tumors

While Boxers, Pugs and Bulldogs are more susceptible for developing MCTs, they usually have less aggressive tumors than other breeds.2

Common cancers effecting dogs

Mast cell tumors are the most common type of cancer that can spread to other areas of a dog’s body.6 But other malignant cancers can affect our furry family members.

Lymphoma

Cancer that arises from white blood cells (lymphocytes) that are an important part of the immune system.

Often accompanied with large, firm lymph nodes in the dog’s jaw, neck, shoulder or back of knees

STELFONTA-Mast-Cell-Tumor-page-different-kind-of-tumors-Lymphoma

Mast cell tumors

Cancer that forms in mast cells, which are a type of immune system cell involved in allergic reactions.

Often appear on or under the skin but can also affect internal organs.

Can look and feel like a cyst, pimple or benign tumor.

STELFONTA-Mast-Cell-Tumor-page-different-kind-of-tumors-Mast-cell-tumors

Hemangiosarcoma

A malignant tumor that arises from cells lining the blood vessels

Located anywhere but most commonly in the spleen and heart

Can rupture, causing serious internal bleeding

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Osteosarcoma

An aggressive malignant cancer that arises from cells in dogs’ bones.

Painful, often causing bone fractures, limb swelling or lameness.

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Melanoma

A cancer of pigmented cells (melanocytes)

Commonly found in dogs’ mouths, melanomas are the most common oral cancer. They are often detected due to bad breath, and rapidly spread.

Also found in haired skin where they are small brown/black masses.

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happy dogs

References

  1. Withrow, S.J. and Vail, D.M. Small Animal Clinical Oncology, Elsevier Inc, Canada 402-421, 2007.
  2. Welle MM, Bley CR, Howard J, Rüfenacht S. Canine mast cell tumours: a review of the pathogenesis, clinical features, pathology and treatment. Vet Dermatol.2008;19:321–339.
  3. McNeil EA, et al. Vet Comp Oncol. 2006;4:2–28.
  4. Murphy S, et al. Veterinary Record. 2006;158(9):287–291.
  5. Withrow SJ, Vail DM. Withrow & MacEwen’s Small Animal Clinical Oncology, 5th Edition. Canada. Elsevier Inc; 2015;335-355.
  6. Brakke Consulting Mid-Year Animal Health Industry Overview 2020
FDA-CVM WARNING: SEVERE WOUND FORMATION IN HUMANS; EXTENSIVE WOUND FORMATION, MAST CELL DEGRANULATION, AND DEATH IN DOGS DUE TO MAST CELL DEGRANULATION Human Safety
  • Accidental self-injection of STELFONTA® may cause severe wound formation. To decrease the risk of accidental self-injection, sedation of the dog may be necessary (see Dosage and Administration, Human Warnings and Adverse Reactions).
Dog Safety
  • Always administer a corticosteroid, an H1 receptor blocking agent (e.g. diphenhydramine), and an H2 receptor blocking agent (e.g. famotidine) when treating with STELFONTA to decrease the potential for severe systemic adverse reactions, including death, from mast cell degranulation (see Contraindications and Dosage and Administration).
  • Do not inject STELFONTA into subcutaneous mast cell tumors located above the elbow or hock (e.g. on the body, head, or neck). This may result in accumulation of necrotic debris in the subcutaneous space increasing the risk of systemic adverse reactions, including death, from mast cell degranulation (see Contraindications, Warnings and Adverse Events).
  • Treatment with STELFONTA has been associated with cellulitis and severe tissue sloughing extending away from the treated site resulting in extensive wounds that require additional treatment and prolonged recovery times (see Warnings, Precautions and Adverse Events).
IMPORTANT SAFETY INFORMATION Formation of wounds, possibly extensive, is an intended and likely response to treatment with STELFONTA along with associated swelling, bruising and pain; these wounds are expected to heal. Appropriate pre- and post-treatment medications must be given, including a corticosteroid plus blocking agents for both H1 and H2 receptors, in order to decrease the potential for severe systemic adverse reactions, including death, from mast cell degranulation. Full prescribing information