How Much Do You Really Know About Dog Tumors?

Many of us who own dogs find that we take the health of our pets even more seriously than our own. The last realization we ever want to come to is that our canine counterpart has a tumor. Unfortunately, dogs get cancer approximately as often as we do, and dogs over ten years of age are especially susceptible.

The prospect of our companions developing a tumor is indeed heartbreaking. However, it does not always have to be a death sentence. Early detection can provide treatment options as well as hope for removal and recovery. Being more educated means being more prepared and giving our pets the best chance of overcoming the odds.

Types of Dog Tumors

Various types of dog tumors can form on our pets. Tumors can appear in numerous places and at different ages. Although tumors are more likely to occur in older pets, younger pets may still be at risk.

Canine Lymphomas

One of the most common types of dog cancers, canine lymphomas are a diverse group of cancers. There are over 30 different types of canine lymphoma, and each of these types differs. Some lymphomas can be extremely aggressive and life-threatening while others can be completely manageable as they progress very slowly.

The cause of lymphoma in dogs is still yet to be known. Some suspected potential factors include bacteria, viruses, and chemical exposures, but not enough evidence exists for any of these to be confirmed causes.

The most common symptoms of canine lymphoma include:

  • Large, non-painful lymph nodes
  • Weight loss
  • Lethargy
  • Loss of appetite
  • Swelling of the legs or face
  • Increased urination or thirst

A biopsy is the most common diagnosis method for canine lymphoma. Performing a biopsy requires heavy sedation or anesthesia.

Chemotherapy is the most efficient treatment method for canine lymphoma although radiation therapy or surgery may also be considerations depending on the type, location, and other factors. In most cases, the dog will experience remission following treatment with minor side-effects.

Prognosis for lymphoma is dependent on a few factors including the type of lymphoma and the kind of treatment used. According to Purdue University’s College of Veterinary Medicine, the median length of survival is between 9-13 months.


Histiocytoma is a type of skin tumor which is unique to dogs. These tumors usually occur in younger animals. Half of canines who develop Histiocytoma are less than two years of age. The most common site for the appearance of these dog tumors are the skin of the dogs’ head and they usually appear as ulcerated lesions which are dome-shaped, approximately 2cm in diameter, and rapid in growth.

Mast Cell Tumors

Mast Cell Tumors (MCT) account for 20% of all skin tumors in dogs. These tumors can appear in many different skin locations throughout the body and can vary in appearance. Surgery is an option although it will depend on the site of the tumor and the surrounding tissue.

The great news is that dogs who have grade I and II tumors completely removed have an excellent prognosis. Partially removed grade I and II tumors treated with radiation therapy still have a great overall prognosis. Roughly 90-95% of dogs in this category have no recurrence within three years of their treatment.


Meningiomaa is the name for the most common type of primary brain tumor in dogs. Membranes that the brain linings consist of form these tumors rather than the brain cells themselves. Long-nosed dogs such as Golden Retrievers are more prone to these types of tumors. Treatment of meningioma is more likely to be successful when it is detected early on. Meningioma usually grows at a slow rate.

There are a few signs that could indicate a brain tumor in our canine companions. These signs include:

  • Changes in behavior, depression, loss of learned behavior
  • Changes in thirst and appetite
  • Circling or pacing around more often than normal
  • Misjudging doorways, bumping into walls, decreased awareness
  • Onset of seizures

MRI’s and CT scans are the typical methods used to diagnose these types of dog tumors. Each test will require administration of general anesthesia. Before performing these tests, a vet will usually want a neurological examination as well as a complete physical and bloodwork to rule out other possibilities and determine if the dog is healthy enough for the required anaesthesia.

Treatment options for brain tumors in dogs include radiation therapy, surgical removal, palliative treatment, and chemotherapy. Unfortunately, the overall prognosis’ are mixed, and data is scattered because owners commonly decide to forego these treatment options.

Canine Soft Tissue Sarcomas

Mesenchymal cells can create a variety of tumors that result in Soft Tissue Sarcomas (STSs). This group of tumors includes peripheral nerve sheath tumors, fibrosarcomas, and hemangiopericytomas. Soft Tissue Sarcomas are typically slow-growing and located on the neck, extremities, or head.

Depending on the size and the location of the tumor, primary treatment usually includes surgical removal. Additional testing such as a CT scan may be necessary to learn more about the extent of the mass.

Nasal Tumors

Nasal tumors are much less common but do affect dogs. The general belief is that longer-nosed breeds in urban environments are more susceptible to this type of tumor. A few warning signs that may indicate a nasal tumor include:

  • Discharge from one or both nostrils
  • Nose bleeds
  • Deformity of the feces
  • Neurological abnormalities

CT Scans are the best way of diagnosing nasal tumors in dogs because they can reveal the exact location and the extent. Sometimes a radiograph of the lungs is requested after diagnosing a nasal tumor to evaluate for metastases.

Radiation therapy is the preferred way to treat nasal tumors, but it will depend on the proximity of the tumor to the brain or eyes. Although this type of cancer in dogs is not curable, radiation therapy can achieve remission as well as a high quality of life.

Keeping Tabs

Paying close attention to our dogs’ overall health is paramount. As owners, we need to constantly be on the lookout for growths, changes in behavior, appetite, or anything else that may signal the presence of a tumor. The faster we can get our best friend checked out and diagnosed, the better chance there is for successful treatment.

Do you have a story to share about your dog’s experience with a tumor? We strongly encourage you to share with us below!

  • January 6, 2017
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