5 Most Common Cancers That Affect Dogs

Just like their human counterparts, dogs can develop cancer. These include bone cancer, bladder cancer, and some you’ve never even heard of.

Mar 30, 2024bySara Payne
cancers that affect dogs

No one wants to find out that their dog has cancer. It can be a devastating diagnosis, but veterinarians can use modern medicine to treat cancers much more effectively than in the past. Early diagnosis and treatment can make a significant difference in the prognosis of your canine companion.

Five major types of cancers affect dogs: osteosarcoma, lymphoma, bladder cancer, leukemia, and gastric cancer. Understanding these five cancers, their signs, treatment options, and prognosis can help you keep your dog comfortable throughout their illness.


boxer dogs
Image credit: Pixabay

Canine osteosarcoma is a malignant bone tumor that can begin in any bone. These tumors are formed from osteoblasts and osteoclasts that are produced abnormally. These cells begin to break down the bone. Most commonly, front and hind leg bones are affected in dogs. This is an aggressive type of cancer that sometimes spreads to other parts of the body.

Some dogs susceptible to this cancer include:

  • Boxers
  • Doberman Pinschers
  • Golden Retrievers
  • German Shepherds
  • Great Danes
  • Greyhounds
  • Irish Setters
  • Rottweilers

The symptoms of this tumor are lameness, swelling of the limbs, lethargy, loss of appetite, and pain that makes it hard to walk or play. Often, by the time there are symptoms, cancer cells have spread throughout the body. This is an aggressive cancer.

However, if it is caught early, there are a few treatment options. The affected limb can be amputated to relieve pain and prevent the spread of the cancer. Post-surgery, your dog will also undergo chemotherapy to control the disease. Your dog may also have radiation therapy.


chow chow
Image credit: Pixabay

Lymphoma is caused by an overgrowth of lymphocytes. Lymphocytes, or white blood cells, normally fight off infections and keep your dog’s body healthy. However, when the lymphatic system has cancer, it can affect many organs throughout the body, including the following:

  • Lymph nodes
  • Spleen
  • Tonsils
  • Organs
  • Tissues
  • Vessels

Lymphoma is typically a cancer found in older dogs, but young dogs can also develop it. Chow Chows, Basset Hounds, Terriers, English Bulldogs, and Poodles are predisposed to developing lymphoma as they age.

Often, the first sign of lymphoma is the swelling of lymph nodes. Other symptoms, such as lesions, vomiting, diarrhea, weight loss, coughing, and shortness of breath, can develop based on the type of lymphoma.

Chemotherapy is the typical treatment for this type of cancer. Surgery and radiation may be options based on the location of the disease. Without treatment, the average prognosis for a dog with lymphoma is about six weeks. With chemotherapy, the dog may live another year.

Bladder Cancer

scottish terrier lying down
Image credit: Pixabay

Bladder cancer, as the name suggests, affects the urinary tract of dogs. This type of cancer is especially common in Scottish Terriers, Shetland Sheepdogs, Beagles, West Highland Terriers, and Wire Hair Fox Terriers. Older, female dogs tend to be most at risk of this type of cancer.

A dog with bladder cancer will often have trouble urinating. They may begin to have accidents around the house. The urine may also be discolored or bloody. They may also suffer from frequent urinary tract infections.

Vets often treat bladder cancer with a combination of surgery, chemotherapy, and radiation. But, due to its location, removing the tumor is often not an option. The prognosis for bladder cancer is sadly only about four to six months without treatment and six months to a year with treatment.


old golden retriever
Photo from Pixabay

Affecting the blood and bone marrow in dogs, chronic leukemia is a slow-progressing disease where the white blood cells are abnormal. They perform their jobs but not well. Acute leukemia produces white blood cells that cannot perform their functions. This is a fast-spreading deadly disease.

Dogs with leukemia generally have the following symptoms:

  • Weight loss
  • Fever
  • Lethargy
  • Lack of appetite
  • Stomach issues like nausea, vomiting, and diarrhea
  • Recurrent infections
  • An enlarged abdomen
  • Enlarged lymph nodes (located near the jaw)

Golden Retrievers and German Shepherds are more predisposed to developing leukemia than other dog breeds. More common in older canines, a dog may also develop leukemia after being exposed to the chemical benzene. This is a naturally occurring substance emitted by cigarette smoke, forest fires, and gasoline.

female vet with dog
Image credit: Wikimedia Commons

Treatment for leukemia does not cure the cancer. It is used to manage symptoms. Vets use a combination of antibiotics, well-balanced diet, chemotherapy, immunotherapy, and medications to manage this disease.

Dogs diagnosed with acute leukemia only have a few weeks to months to live. Dogs with chronic leukemia may live several months to years with treatment.

Gastric Cancer

german shepherd
Photo from Pixabay

German Shepherds, Bouvier des Flandres, Collies, Poodles, and Norwegian Elkhounds have a higher incidence of developing gastric (or stomach) cancer. This type of cancer is often diagnosed in male dogs that are over nine years old. Some studies suggest that exposure to nitrosamines (a preservative) may increase the susceptibility to this disease.

Gastric cancer symptoms include the following:

  • Weight loss
  • Bloody vomit
  • Irregular urination and bowel movements
  • Licking parts of the body
  • Nipping when touched

This type of cancer is very painful. Often, by the time it is diagnosed, the dog is already in an advanced stage of cancer. Most dogs diagnosed with gastric cancer only live around two months without treatment. With chemotherapy and surgery, a dog may be able to live up to six months.

Worried About Your Dog? Consult a Vet

old dog
Photo from Pixabay

If you are worried your dog may have cancer, it is important to get them checked out by a veterinarian. You could spend all day researching your options, but ultimately, only a vet can answer your questions, diagnose your dog, and plan for treatment. Often, catching cancer early can make treatment easier. It can even save your pal’s life!


Q: Are there any specific signs that distinguish one type of cancer from another in dogs, helping owners identify the specific cancer type earlier?

A: Specific signs distinguishing cancer types can include the location of swelling, sudden changes in behavior related to a particular body part, or symptoms unique to an organ system, aiding in early identification.


Q: What preventative measures can dog owners take to reduce the risk of their pets developing these types of cancers?

A: Preventative measures include regular veterinary check-ups, a healthy diet, avoiding exposure to known carcinogens, and maintaining a healthy weight.


Q: How do veterinarians determine the stage of cancer in dogs, and how does the staging influence the treatment plan and prognosis?

A: Veterinarians determine the stage of cancer through diagnostic tests like blood work, X-rays, ultrasounds, and biopsies. The cancer stage influences the aggressiveness of the treatment plan and helps in giving a more accurate prognosis.

Sara Payne
bySara Payne

Sara is a mother of two and a high school English teacher who rediscovered her love of writing during the pandemic. She has 5 rescue cats: Neville and Luna, who are white cats with black and grey spots, and Ginny, Blue, and Fairy, who are calicos. Besides taking care of humans and fur babies, Sara enjoys gardening, crafting, and spending time in nature.