Top 5 Cancers in Dogs

Cancer can afflict dogs of all ages, especially older dogs.  We know how devastating it can be to get a diagnosis of cancer in your dog. However, just like humans, cancers your dog may have that are caught early are treatable and sometimes cured.

Cancer means the unrestrained cell division and growth.  Normally, cell division is tightly regulated.  When a single cell undergoes a series of genetic mutations, cancer may arise, causing cell division to become unregulated, resulting in a tumor.

While symptoms of canine cancer vary, watch out for things like a lump or a bump on your dog, a wound that does not heal any kind of swelling or enlarged lymph nodes, lameness or swelling in the bone or abnormal bleeding. Many times there are little or no signs, at least early on.  Please contact your family veterinarian if you notice any of these symptoms in your dog or if your dog “just isn’t quite right”.


Mast Cell Tumors – Mast cell tumors found most commonly on the skin.  Mast cells are cells that reside in the connective tissues, especially the vessels and nerves that are close to the external surface of your dog (skin, lungs, nose, and mouth).  Mast cell tumors are graded according to their location in the skin, presence of inflammation and how well they are differentiated.  Less commonly, they can arise internally.

Melanoma – Melanoma is a common type of cancer in dogs and is the most common malignant tumor of a dog’s mouth.   They are usually black in color, but not always.

Lymphoma – Lymphoma is a cancer of a type of blood cell (lymphocyte) and lymphoid tissues.  Lymphoid tissue is present in many places in the body, including lymph nodes, spleen, liver, gastrointestinal tract and bone marrow.

Bone Cancer (Osteosarcoma) – Osteosarcoma refers to the most common bone tumor found in dogs. Bone cancer can affect any breed of dog, but it is more commonly found in the larger breeds.

Hemangiosarcoma – Hemangiosarcoma is a highly malignant cancer that can spread rapidly, causing tumors almost anywhere in the body. It is most often found in the dog’s heart and spleen. Many times it is in the advanced stage before it is diagnosed.