Common Types of Cancer in Canines

Are you afraid your dog might have cancer? This guide will help you learn more about the different types of cancer that are common in canines and what warning signs and symptoms to watch out for.

Although cancer is the leading cause of death in dogs over ten years of age, half of all of the cancers a dog can develop are actually curable, as long as they are identified and treated early.

Dogs are susceptible to just as many forms of cancer as humans are, but the most common types found in canines include osteosarcoma, lymphoma, skin cancer, breast cancer, mouth and/or throat cancer, and hemangiosarcoma.

Common Types of Cancer in Canines


Osteosarcoma is the most common type of bone cancer in dogs. While it can affect almost any age or breed of dog, it is most commonly found in older and large-breed dogs.

This type of cancer usually involves some sort of abnormal bone production. Osteosarcoma is a very aggressive form of cancer, but it can be treated with chemotherapy and radiation therapy. The problem is that almost all dogs who develop it eventually succumb to it simply because the disease often goes undetected and undiagnosed until it is in its late stages.


Lymphoma is the most common type of cancer found in veterinary medicine, but it is not all that common among dogs. There are some breeds that are more at risk of developing the disease than others. These breeds include Basset Hounds, Boxers, Saint Bernard, Scottish Terriers, Airedale Terriers, Bulldogs, and Golden Retrievers.

Lymphoma originates in the white blood cells of the immune system, but its exact cause is yet unknown. Lymphoma can be treated using chemotherapy and radiation therapy, and in some cases a veterinarian may be required to treat the dog’s liver, spleen, lymph nodes, and in some cases the bone marrow if the cancer has progressed too far, but there is no known cure for the disease. While a dog may go into remission post-therapy, relapses aren’t uncommon.

Skin Cancer

Skin cancer is a common type of cancer found in dogs and there are a few different varieties of it, including malignant melanoma, squamous cell carcinoma, and mast cell tumors.

Malignant melanoma is a type of cancer that affects a dog’s pigmented cells, or melanocytes. In most cases of malignant melanoma, the tumors develop on the mouth or mucous membranes. They can also form on parts of body covered by hair, but this only occurs in about 10% of cases. Malignant melanoma produces very fast-growing tumors that are also quick to spread to other organs, including the lungs and liver.

Squamous cell carcinoma is a skin cancer that’s caused by exposure to the sun’s UV rays. This type of cancer doesn’t usually spread to the lymph nodes, but it can cause rapid destruction of the tissue surrounding the tumors.

Mast cell tumors are the most common type of skin cancer found in dogs and they can be either slow-growing or fast-growing. In aggressive cases, the tumors can ulcerate. This type of cancer occurs in the mast cells of the immune system. In a quarter of the cases, the tumors are found on the legs, but the majority of the time, they tend to develop on the dog’s trunk.

Breast Cancer

Breast cancer is proliferous among female dogs. In fact, more than half of all cancerous tumors detected in female dogs are mammary tumors. This makes breast cancer the most common type of cancer to affect female dogs.

A female dog that was never spayed or that was spayed after her first heat cycle is especially high at-risk for breast cancer. Other risk factors include a diet that’s high in meat, obesity, and an age of older than one year. Breast cancer is also more prevalent in certain breeds, such as Toy Poodles, English Springer Spaniels, German Shepherds, and Pointers.

Mouth and/or Throat Cancer

Dogs can suffer from a variety of different cancers in the mouth and/or throat. These types of cancers tend to be very aggressive, so very strong treatment methods are needed in order to eradicate them.

Gingival squamous cell carcinoma is one of the most common types of oral cancer among canines. It metastasizes extremely quickly, often invading nearby tissue and bone, making it a very deadly cancer among dogs. This cancer is most commonly seen in dogs ten years or older, but it is not restricted to older dogs.

When a dog has cancer in the throat, she is diagnosed with chondrosarcoma. This is a rare type of cancer that causes tumors to affect the larynx and trachea. Similar to gingival squamous cell carcinoma, chondrosarcoma spreads to the surrounding cartilage and connective tissues very quickly. It is most commonly found in older male dogs.


Hemangiosarcoma is a cancer that affects the blood vessels in the body, most commonly those in the liver and spleen. It starts in the lining of the blood vessels and if it is left untreated, it eventually spreads to the skin, liver, heart, spleen, and other organs in the body.

Its tumors are highly metastatic and malignant, and in severe cases, they can fill with blood and rupture, causing a very sudden and severe hemorrhage that results in collapse and rapid death. Often, dog owners aren’t even aware that their dog has this type of cancer until a hemorrhage occurs or she suddenly collapses.

How to Reduce Your Dog’s Risk of Cancer

Cancer is an especially secretive and destructive disease that most people associate with certain death. But, many cancers can be prevented or even treated. In order to help improve your dog’s ability to avoid cancer, certain steps can be taken.

For starters, you should spay or neuter your dog at an early age because this can help prevent reproductive cancers. You can also add antioxidant supplements to your dog’s diet. Vitamins A, C, E, beta carotene, lycopene, and the mineral selenium have been shown to help protect against cancer. Of course, feeding your pet a healthy and well-balanced diet, providing her with plenty of clean drinking water, and ensuring she gets plenty of daily exercise will also help keep cancer at bay.

Another important step is to take your dog to regularly scheduled veterinarian appointments. This will help ensure your dog is healthy, and in the event there is a cancer concern, the vet will be able to catch it early enough for the treatment to have the best chance of working.

Signs and Symptoms of Cancer in Dogs

When a dog develops cancer, she will start exhibiting certain physical and behavioral changes, including:

  • Difficulty urinating or defecating
  • Vomiting
  • Diarrhea
  • Bad breath or foul bodily odors
  • Pale gums
  • Sudden-onset lameness
  • Tarry, black stools
  • Sores that don’t heal
  • Lumps or swelling on the skin
  • Sudden weight loss
  • Loss of appetite
  • Difficulty breathing
  • Abnormal discharge from any bodily opening
  • Whimpering

If you notice one or more of the above signs, take your dog to the veterinarian immediately. In the event your veterinarian decides to prescribe medications for your dog, you can receive a free quote for the medication from Diamondback Drugs. We can help you save money on all of your pet medications.

As always, be sure to inform your veterinarian about any medications or supplements your dog is currently taking so your vet can make the best treatment decision for your pet’s unique case and help reduce the risk of a potential drug interaction.


Author: Giano Panzarella