Liver cancer is luckily not a very common cancer in dogs. The Pet Cancer Center estimates that tumors of the liver make up only about 1.5% of all canine tumors. However, liver cancer is significantly more treatable when it is discovered early, so it is important to recognize any symptoms and other signs of cancer in dogs.

Below is a list of the most common symptoms of liver cancer in dogs, so you will catch the signs as early as possible—take your dog to the vet if you notice any of these symptoms, as every case is unique and testing will be needed to determine if your dog has liver cancer.

What is Canine Liver Cancer?

Most liver tumors in dogs are metastatic tumors of the liver. This means that the cancer has spread from another organ in the dog’s body, and did not originate in the liver. Metastatic tumors of the liver are often benign, which is a good sign for your dog.

Though there is a smaller chance of your pet having primary liver tumors, or tumors that did originate in the liver, it can still happen. Over 50% of primary liver cancers in dogs are Hepatocellular Carcinomas. These start in the liver and rarely spread outside of the liver, but are typically malignant and can be more difficult to treat than benign tumors.

Causes of Liver Cancer in Dogs

No known cause has been discovered for liver cancer in dogs, including no signs of any breed predisposition. Studies have shown that liver cancer is more common in dogs over 10 years of age, so this may play a factor in the causing of liver cancer. There have been some studies that also suggest liver cancer is more common in male dogs, but this is not as widely proven.

Symptoms of Liver Cancer in Dogs

Some warning signs of liver cancer include, but are not limited to:

• Decreased appetite
• Weight loss (over 10% of his/her body weight in a short period of time)
• Lethargy
• Significantly increased thirst
• Vomiting or Diarrhea
• Abdominal mass
• Jaundiced or yellowed eyes
• Frequent or bloody urine
• Confusion or disorientation

Diagnosing Liver Cancer in Dogs

If your vet thinks your canine has liver cancer, they will check for any masses or abnormalities in the abdominal area. Blood and urine tests will then determine the functionality of the liver, but the only definitive way to tell if your dog has liver cancer is to check for tumors by doing an x-ray or ultrasound.

Types of Liver Cancer in Dogs

The types of liver cancer found in dogs are determined by the size and shape of the tumors that they form. Massive tumors are typically one large mass, as opposed to Nodular tumors which are smaller masses in various places on the liver. The Nodular tumors are more likely to metastasize or spread to other organs than Massive tumors.

Diffuse cancers refer to cancer cells that are diffused throughout the liver and not in discrete masses—this is the type that is most difficult to treat as there is no mass to remove. A hepatocellular adenoma refers to a benign tumor of the liver; these are less dangerous but may still need to be removed depending on their placement.

Treatment of Liver Cancer in Dogs

There are a few treatment options depending on the exact type of cancer your dog may have. The most likely fix would be to have the tumor or tumors removed via surgery. The liver can actually regenerate itself after surgery, so your dog will be able to recover from the surgery, but he will need to be monitored closely and put on a diet that is low-stress for the liver.

Chemotherapy, radiation, and medicine are all alternative methods depending on the type and severity of the particular cancer your dog has. Most liver cancers are treated with a combination of several of these methods. Every case is unique and should be treated as such —you will probably visit with a veterinary oncologist to determine the most appropriate treatment for your dog’s case.

Though there is no singular type of liver cancer that appears in canines, there is a great deal of information available on how to treat your dog’s cancers if they appear. The most important thing in dealing with liver cancer is early detection, so make sure you take your dog to the vet quickly if you notice any of the symptoms listed above—especially bloody urine or a mass in the abdomen.