Canine Liver Cancer
Canine liver cancer can be primary (originated in the liver) or metastatic (originated somewhere else and spread to the liver). Symptoms of liver cancer in dogs can be vague and indistinct, such as appetite loss, lethargy, and vomiting. It is therefore difficult to diagnose. Prognosis is poor because diagnosis is often made too late for treatment to be successful.

The liver is the largest organ in the dog’s body, and it is a vital organ responsible for a large number of bodily functions and processes, such as metabolism, storage of glucose (glycogen), decomposition of red blood cells and plasma protein synthesis.

In addition, the liver is one of the main organs responsible for detoxifying many toxic substances circulating in the body.

Two forms of liver cancer can occur in dogs – primary and secondary (metastatic).

Primary liver cancer occurs when there is a tumor that is growing in the liver.

The most common type of primary malignant liver tumor is hepatocellular carcinoma. This tumor usually is locally invasive – it invades into the liver tissue and rarely spreads to other locations of the body.

Another primary liver tumor is hepatoblastoma. It is rather rare but is also malignant and can metastasize to sites such as regional lymph nodes, lungs, kidneys, pancreas, spleen and others.

Primary liver cancer is not common (less than 1.5% of all dog cancers), and it usually occurs in dogs that are 10 years of age or older.

For some reasons, male dogs seem to be slightly more susceptible to primary liver tumors.

The exact cause of primary liver cancer in dogs is not clear, but it is suspected that exposure to carcinogens (cancer-causing agents) such as certain pesticides may be a possible trigger.

Metastatic liver cancer is cancer that has originated elsewhere in the body (particularly in the spleen, pancreas, and the gastrointestinal tract), and has spread to the liver.

The liver is a common target for metastasis for several reasons:

  • It is the largest organ in the body.
  • One of its functions is detoxification of toxic substances.
  • Two blood vessels, instead of one, supply blood to the liver, so it is more susceptible to cancer cells that are traveling through the blood circulation.

Symptoms of Canine Liver Cancer

Unfortunately, signs and symptoms of canine liver cancer are often nonspecific. As the cancer progresses, it can cause some of the following symptoms:

  • Loss of appetite
  • Weight loss
  • Vomiting
  • Lethargy
  • Increased thirst
  • Excessive urination
  • Fluid accumulation in the peritoneal cavity (the space within the abdomen that contains the intestines, the stomach, and the liver)

In addition, as the disease is more advanced, the dog will show symptoms such as:

  • Stools with blood (due to internal bleeding)
  • Anemia
  • Pale gums (due to anemia)
  • Jaundice

Note that some other diseases involving the liver can cause similar symptoms as described above.

For example, liver infections, hepatic abscesses. hepatitis and leptospirosis all cause similar symptoms.

It is therefore extremely important to get your dog to the vet for a proper diagnosis if he shows some of the above signs.

Diagnosis of Canine Liver Cancer

Diagnosis is usually made by the following procedures:

  • Blood tests (elevated white blood cell count, low red blood cells, and high platelet counts in the blood are common in dogs with liver cancer)
  • Biochemical profile to measure albumin (a blood protein made by the liver), blood sugar, blood urea nitrogen, etc. will be used to assess liver function
  • X-rays, CT scan or MRI will be used to check for the presence of masses in the liver
  • Fine-needle aspiration or liver biopsy can be used to obtain samples of the tumor for analysis of malignancy

Conventional Treatment of Canine Liver Cancer

For primary liver cancer caused by a solitary tumor that has not spread throughout the liver and has not metastasized, surgery to remove part of the liver is possible.

As much as 80% of the liver can be removed without causing harm.

Many hepatocellular carcinomas are single masses and operable. If all the cancerous tumor and cells can be successfully removed, the dog can survive at least one year or so after surgery – some even longer (for several years).

Some malignant tumors (e.g. nodular and diffuse hepatocellular carcinoma) cannot be removed surgically because multiple liver lobes are involved.

Also, surgery is not effective if the cancer has metastasized to other parts of the body.

For these cases, treatment by chemotherapy may be suggested.

However, chemotherapy is not so effective in treating primary liver tumors since they are highly resistant to chemotherapy drugs. As a result, prognosis is poor if chemotherapy is the only treatment protocol.

As you can see, there are not too many conventional treatment options for liver cancer in dogs.

In addition, most liver cancer cases are diagnosed rather late due to a lack of distinctive symptoms in the early stage, and the liver can continue to function for a while even with cancer. As a result, canine liver cancer generally carries a very poor prognosis.

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