Cancer in your pet

The word “cancer” is probably one of the most feared words in our world today; and unfortunately that doesn’t stop with humans – it affects our pets as well.  According to the National Canine Cancer Foundation, it is a diagnosis one out of every three dogs will receive in their lifetime.  There are many different types of cancer but the five most common in canines are mast cell tumors, melanoma, lymphoma, osteosarcoma and hemangiosarcoma.


Mast cell tumors are a form of skin cancer.  Mast cells are found in the connective tissues, especially around the surface of the dog – skin, lungs, nose, and mouth.  The first sign of a mast cell tumor is commonly a lesion on the skin.  They are most common in older dogs and in breeds such as boxers, Boston terriers, labs, beagles and schnauzers. 

Melanoma is another form of skin cancer and is highly aggressive, growing deep into the skin to invade vital organs.  The majority of melanoma tumors start in the mouth or around the lips, but can also be found in the nail beds, footpads, and eyes.  The first signs often appear as a swollen paw, a draining eye, or a sore in or around the mouth.

Lymphoma occurs in the lymph nodes and bone marrow, affects a dog’s immune system, and can spread rapidly if left untreated.  It is most commonly diagnosed in dogs between the ages of six and nine years old.  Typical first signs are a painless, swollen lymph node in the neck or behind the knees. 

Osteosarcoma is a cancer of the bone.  Most of the tumors are malignant and grow very rapidly and while they can occur in any bone, they most commonly affect the limbs.  They are most often found in dogs between the ages of 4 to 7 and in breeds such as Great Danes, Irish setters, Dobermans, Rottweilers, German shepherds, and golden retrievers.  Initial signs may include swelling and lameness. 

Hemangiosarcoma is a malignant cancer of the blood vessels.  It is most common in the spleen, liver, and heart but can be found in any organ just under the skin.  Unfortunately, because there are typically no early warning signs, most dogs are not diagnosed until it has reached advanced stages.  It is most commonly seen in, but not limited to, golden retrievers and German shepherds. 


These are just five of the most common cancers but there are many more forms.  One thing all forms of cancer have in common is that finding them early is the most helpful way to treat them.  Early warning signs of any cancer may include:  abnormal swelling, a sore that doesn’t heal, weight loss, loss of appetite, bleeding or discharge from any opening on the body, unusual odor, difficulty eating or swallowing, lethargy, ongoing lameness, and difficulty breathing, urinating or defecating.  If you notice any of these symptoms in your pet, contact your veterinarian.  They will most likely recommend a type of biopsy and sending off a tissue sample for pathology.  This will be the most effective way to diagnose if and what type of cancer your pet may have, as well as the best way to treat it.  Veterinary medicine has made large strides in cancer treatment in recent years.  Typical treatment methods include chemotherapy, radiation and surgery – sometimes alone or in combination with one another.  Annual check-ups with your veterinarian will be the most effective way to diagnose any form of cancer in its early stages, and in turn, the most effective way to prolong your pet’s life.