8 Types of Cancer in Dogs, Dog Cancer Signs & Treatments

Sharing is caring!

Tips on detecting cancer in dogs and finding effective treatments to combat it. It’s widely understood that cancer that can manifest in virtually any organ in the human body. What some people don’t realize, however, is that it often affects animals, too.

One in every four dogs [BV1] is diagnosed with cancer in its lifetime. The likelihood of diagnosis increases in dogs over ten years old [BV2]. Although some types of cancer in dogs are more common than others and therefore more receptive to treatment, we would handle each type uniquely. Here are eight of the most common cancers in dogs and how to approach treatment.


dog melanoma signs

While this can be a scary diagnosis, thankfully, 90% of all cutaneous (skin) melanomas are benign. However, tumors arising in the mouth or from the toes are often malignant and aggressive and can spread quickly; therefore, early intervention is critical. Surgery, radiation therapy, and immunotherapy can help. In addition, a melanoma vaccine (immunotherapy) can help stimulate a dog’s body to make antibodies to help fight this disease.


Dog Osteosarcoma Signs

Osteosarcoma is the most usual form of bone cancer in dogs. We see Osteosarcoma commonly in large or giant breeds, which is more common in males, often seven years or older. However, there is a subset of dogs that may be diagnosed at between 1.5 and 2 years of age as well. 

Symptoms of Osteosarcoma may include progressive lameness of a leg to not wanting to use the body part at all. There is also a risk of fracture in the limb affected. 

Treatment options include a combination of amputation, chemotherapy, radiation therapy (which may help preserve the limb), and palliative medications. Many dogs can live a good quality of life for one to two years after diagnosis with treatment.  

Mast Cell Tumors

dog mast cell tumors

Mast Cell Tumors are the most common skin tumors seen in dogs. Some of these tumors will only affect the skin. In contrast, occasionally, others will affect other organs such as the lymph nodes, spleen, liver, and bone marrow. 

The grade of the tumor makes a big difference in terms of the prognosis and treatment options. Some tumors can be cured with surgery or radiation, while other tumors can spread and may need chemotherapy.   


lymphoma signs dogs

Lymphoma is the most common form of cancer in dogs. Lymphoma can present in the lymph nodes, spleen, liver, chest, and GI tract. However, we find Lymphoma most often in the peripheral lymph nodes; you may notice lumps under your dog’s neck, in his groin, or behind his knees in his rear legs. 

Chemotherapy is the treatment of choice and can often yield a long remission; occasionally, radiation therapy can help. For families who decline chemo, prednisone pills can slow the disease for a short while. 

Mammary Cancer

mammary cancer signs dogs

We see mammary tumors more commonly in unspayed dogs or those spayed at two years of age or older. Dogs spayed as puppies (6 months of age or younger) have a 0.8% chance of being afflicted with this cancer. Fifty percent of all mammary tumors in a dog are benign, and 50% are malignant. 

Surgery is the mainstay of therapy and the only way to distinguish whether the tumor is benign or malignant. In addition, chemotherapy may be recommended, depending on the aggressiveness of cancer. 


Hemangiosarcoma Dogs

Hemangiosarcoma is the most common tumor in dogs arising from the spleen; it occurs in the lining of a blood vessel. Hence, it has immediate access to the bloodstream. While any dog can develop hemangiosarcoma, golden retrievers, German shepherds, and boxers are more likely to get it. 

Typically, dogs are ten years of age or older when diagnosed, and it can strike dogs of either gender. These tumors can also spread to (or begin in) the liver, lymph nodes, lungs, and heart (right atrium) in addition to the spleen. 

Dogs with hemangiosarcoma may have pale gums, be lethargic, lose weight, or even collapse for no reason. Surgery and chemotherapy may be of help. 

Transitional Cell Carcinoma 

Transitional Cell Carcinoma

Transitional Cell Carcinoma is the most common bladder tumor seen in dogs. 

Female dogs and terriers are more likely to develop transitional cell carcinoma, though any dog could get this disease. Your dog may have blood in their urine, strain to urinate, strain to defecate, or have a change in stool shape.

 If your dog cannot urinate, seek veterinary care immediately! Treatment options include surgery, chemotherapy, radiation therapy, or a nonsteroidal pill to help slow the disease’s progression.  

Lung cancer

dog lung cancer

While this condition is relatively rare in dogs, older dogs can fall victim to lung cancer. Though this affects less than 1% of dogs, adenocarcinoma of the lung comprises 75% [BV4] of primary canine lung tumors. 

Your dog may have difficulty breathing, a poor appetite, lethargy, fever, or pain. Treatments include radiation after surgery to remove the tumors or chemotherapy if cancer has spread.

If this article regarding cancer in dogs was helpful, please consider sharing it with other dog lovers. If you are interested, please check out our FaceBook page @ Canine Owners | Mixed & Purebred Dogs. You can also follow us on Twitter & Pinterest.