Reviewed and updated for accuracy on August 9, 2019 by Dr. Hanie Elfenbein, DVM, PhD
Liver cancer in dogs is usually caused by a malignant tumor called a hepatocellular carcinoma. This malignant tumor forms in the tissue that lines the cavities and surfaces of the liver.
Hepatocellular carcinomas are quite rare in dogs and significantly less common than benign liver tumors in dogs. However, they account for more than 50% of all types of malignant liver tumors.
Unlike in humans, this type of dog liver cancer has no known association with viruses like hepatitis or cirrhosis.
Types of Dog Liver Cancer
These are the types of hepatocellular carcinomas:
Massive: a single, large tumor typically confined within a single section of the liver (called a lobe).
Nodular: several nodules within one or a few liver lobes.
Diffuse: widespread nodules in all liver lobes.
Symptoms of Liver Cancer in Dogs
Your dog may show no signs of illness until the disease reaches an advanced stage. The following symptoms are typically only seen once dog liver cancer is in the advanced stages:
Loss of appetite (anorexia)
Paleness (anemia) or yellowness (jaundice) of the skin
Excessive thirst (polydipsia)
Swollen abdomen, especially uneven swelling
Most of the time, there is no known cause for liver cancer in dogs. There are no breed predispositions for liver cancer, but affected dogs are, on average, older than 10 years of age.
Dogs with a history of chronic inflammation or liver damage may have an increased risk for developing cancer. Specifically, some types of toxins that damage the liver may make your dog more prone to liver cancer.
Your veterinarian will perform a thorough physical exam on your dog, including a chemical blood profile, a complete blood count and a urinalysis.
Diagnostic imaging will include an abdominal ultrasound to assess the tumor and look for other organ involvement, as well as X-ray imaging of the chest to see if it has spread into the lungs.
The vet will take cells from the liver by needle (fine-needle aspiration) and study them under a microscope to determine whether they are cancerous (hepatocellular carcinoma or another type of liver cancer) or benign (hepatocellular adenoma).
The needle aspiration may not always be conclusive, so occasionally, a hepatic biopsy will need to be conducted in order to make the diagnosis. For this, your veterinarian will need to surgically remove a sample of liver tissue for laboratory analysis.
Fortunately, there are more treatments available for liver cancer in dogs than there were even five years ago.
Surgical removal of the tumor is recommended, when possible, and is often most successful when the tumor is a discrete mass that’s confined to one section of the liver.
Up to 75% of the liver can be surgically removed without pronounced loss of function.
However, nodular and diffuse forms are often not good candidates for surgery. As a result, these types of dog liver cancer have a poor prognosis.
Your veterinarian may refer you to a veterinary oncologist for care. Not all veterinarians are comfortable surgically removing part of the liver.
Chemotherapy may be recommended for your dog. However, only some liver tumors are sensitive to chemotherapy, so whether to pursue treatment is an important conversation to have with a veterinary oncologist.
Life Expectancy for Dogs With Liver Cancer
The best case scenario is that your dog has a single mass that can be completely removed surgically. Then your dog can live healthfully for another four years or more.
Diffuse and nodular liver cancers in dogs have a poor prognosis.
If your dog already has evidence of cancer in other abdominal organs or in the lungs, the prognosis is grave and your dog may only have a few weeks left.
If your dog is not a surgical candidate, the life expectancy for dogs with liver cancer is about six months. Even with a surgery that is only partially successful, life expectancy goes up to a year or more.
Close monitoring by your veterinarian can keep your dog as healthy as possible for as long as possible. Symptoms can be managed even if the illness cannot be cured.
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