Cancer of the liver most often occurs in older cats who are 10 years of age or older; male cats have a slightly greater risk of developing liver tumors than females. Treatment depends on whether the liver tumor is benign or malignant and what other organs (if any) are involved.

Liver tumors in cats, also known as hepatic neoplasia, occur when a primary tumor develops in the liver, when cancer develops in the blood cells or lymphoid tissue that involve the liver, or when a different type of cancer metastasizes and spreads to the liver. Primary liver cancer is rare in cats and accounts for less than two percent of all cases. The majority of liver cancer occurs when cancer of the spleen, pancreas, or intestinal tract becomes metastatic.

Symptoms may vary depending on if the tumor is benign or malignant and if the tumor has metastasized from another primary cancer in the cat's body. These symptoms include:

There are several different types of primary liver tumors, including:

There is no known cause of liver tumors. Researchers believe that age could be a risk factor. The older a cat is, the more cell divisions that its body has gone through, increasing the risk of a mutation. Other possible risk factors include genetics, consumption or inhalation of chemicals or toxins, chronic inflammation, and hepatotoxicity.

The veterinarian will need to know the cat's complete health history, which will include what symptoms are present and when the symptoms first began. The veterinarian will examine the cat, feeling for any enlarged lymph nodes or abdominal enlargement and listening to its breathing and heart. Because liver tumors are often asymptomatic until they grow and spread to other organ systems, the tumor may be found during a routine exam.

Several labs will be taken, which will include a complete blood count, biochemical profile, an electrolyte panel and a urinalysis. These labs don't test for liver cancer but can show signs of liver damage or bile duct obstruction, which can lead to further testing. An abdominal ultrasound and chest x-ray will be performed to look for evidence of a tumor or metastasis to the lungs and to eliminate other conditions. To make a definitive diagnosis, the veterinarian will need to do a liver biopsy. This will be done via a needle that is inserted into the liver to remove a sample of tissue, or during surgery to remove a small portion of the liver tissue. These samples will then be tested for cancer cells.

Surgery is the preferred treatment for primary liver tumors. Because the liver is regenerative, up to 75 percent of the liver can be safely removed to eliminate the tumor while still preserving function. The cat will be placed under general anesthesia during the surgery. An incision will be made in the abdomen, the tumor will be removed, along with a portion of the liver to ensure margins are clear. The incision will then be closed with sutures. Surgery is normally successful, even for large tumors, when the tumor hasn't spread beyond the liver.

Chemotherapy may be utilized to slow the progression of cancer that has spread to other organs beyond the liver or for the treatment of primary cancers that have metastasized to the liver. Chemotherapy has a variety of side effects, however, and should only be attempted if these side effects can be managed and if regular abdominal ultrasounds indicate that the chemotherapy is effective in shrinking the tumor.

Medications for pain management may be prescribed in order to keep the cat comfortable and free from the pain of the tumor. Antibiotics will also be prescribed after surgery to ensure that infection doesn't occur.

When caught early, primary liver tumors have a high success rate after surgery and have a good prognosis. The cat will need to regularly follow up with the veterinarian to monitor the liver for signs of the cancer returning. Cats who have a liver tumor that has metastasized from another primary cancer or have primary liver cancer that has spread have a poor prognosis. The cat will need to be cared for at home and proper care will need to be taken to keep the cat comfortable.

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