Is Your Pet Sleeping on a Hotbed for Bile Duct Cancer?

Story at-a-glance -

  • Bile duct cancer, or biliary carcinoma, is a common type of liver cancer in both cats and dogs, primarily seen in pets over the age of 10. This type of cancer is very aggressive, with metastasis occurring in 80 percent of patients
  • A suspected cause of biliary carcinoma is environmental exposure to carcinogens, so it’s important to reduce your pet’s exposure to food-borne carcinogens in kibble, fabrics or pet beds treated with flame-retardants, and chemical pesticides/herbicides
  • Symptoms of bile duct cancer include a swollen abdomen, lack of appetite, lethargy, excessive thirst and urination, vomiting, and jaundice
  • The treatment of choice for biliary carcinoma is surgery. Even with successful tumor removal and no metastasis at the time of surgery, the prognosis for pets with this type of cancer is poor

By Dr. Becker

There are two types of bile duct tumors that affect dogs and cats. One is biliary adenoma, which is a benign tumor, and the other is biliary carcinoma, which is malignant (cancerous).

Benign biliary adenomas are the most prevalent type of liver tumor in cats, accounting for over 50 percent of all feline primary liver tumors. These cysts are large and filled with fluid, and they typically don’t cause problems until they grow so big that they begin pressing on other organs. Treatment of these cysts, if they become a problem, involves either draining the fluid every so often or removing them surgically.

Biliary Carcinoma in Cats and Dogs

The topic of today’s discussion is the other type of bile duct tumor, which is biliary carcinoma. Biliary or bile duct carcinoma is the most common type of liver cancer in cats and the second most common in dogs. The disease typically affects animals over 10 years of age.

Biliary carcinoma usually originates in the cellular lining of the liver bile ducts. It occurs more often in the bile ducts within the liver, called intrahepatic bile ducts, than in the extrahepatic bile ducts located outside the liver. In dogs, these tumors are more likely to be found in the left lobe of the liver. 

Unfortunately, bile duct cancer is very aggressive, with metastasis (spreading of the disease) occurring in about 80 percent of both dogs and cats. When the cancer spreads, it can move anywhere, but usually involves the lungs. It can also spread to the lymph nodes, abdominal lining, intestines, pancreas, spleen, kidney, and bladder, as well as the bone. Complications of the disease include blockage of bile within the bile ducts.

Causes and Symptoms

Suspected causes of biliary carcinoma are parasitic infections as well as environmental exposure to carcinogens. I recommend keeping your pet really healthy, which includes reducing potential food-borne carcinogens created during the dry food extrusion process. I also recommend reducing your pet’s exposure to household toxins such as fabrics or pet beds that have been treated with flame-retardants. Eliminating lawn and garden pesticides and herbicides is also really smart.

A dog or cat with bile duct cancer usually has a round or swollen abdomen caused by an enlarged liver and/or fluid in the abdomen. Other common symptoms include lack of appetite, lack of energy, excessive thirst and urination, vomiting, and yellowing of the skin or whites of the eyes, which is called jaundice.

Diagnosis and Treatment

In addition to performing a physical examination on your pet, your veterinarian will order a chemical blood profile, a complete blood count (CBC), and a urinalysis. He or she will be looking for elevated liver enzymes that indicate the liver is inflamed or has spilled enzymes into the bloodstream, indicating liver damage.

X-rays and an ultrasound will also be needed to provide information on the texture and size of the liver and nearby abdominal organs. If cancer is suspected, your pet’s lungs will also be X-rayed to see if the disease has spread there and to evaluate the size of the lymph nodes in the chest cavity. A liver biopsy will be required to confirm the presence of cancer. Often this biopsy can be obtained by a fine-needle aspiration. If your pet has fluid in the abdomen, your veterinarian will probably collect a sample for analysis.

Surgery to remove the cancer is the treatment of choice for biliary carcinoma. Chemotherapy is not recommended because it hasn’t been found to be effective against this disease in dogs or cats. Sadly, even with successful surgery and little to no metastasis of the cancer throughout the pet’s body, the prognosis for pets with bile duct cancer is very poor.

In my opinion, partnering with a holistic veterinarian who can provide an integrative protocol that focuses on managing your pet’s quality of life, pain control, and great natural options to assist in immune and detoxification support, is the best treatment approach for this devastating disease