Liver Cancer In Dogs
A properly functioning liver is critical to a dog’s health. The liver filters blood and plays key roles in digestion and metabolism, among many other jobs. Fortunately, liver cancer in dogs is very rare, with only about 1% of dogs experiencing it. They typically are 10 years of age or older, and no particular breeds are more likely than others to be stricken. Nor is a dog’s sex a factor.
There are several types of liver tumors. They are often slow-growing, and not all liver tumors are cancerous. Treatment modalities depend on the type of tumor and, if it is cancerous, how far the cancer has advanced before detection. Treatment options may include surgery, stereotactic radiation, chemotherapy or some combination of these. Many dogs respond well and go back to living their normal lives for periods ranging from several months to well over a year.
Types of Liver Tumors in Dogs
As is the case with humans, some dog organs have lobes, which are rounded projections of the organ. A dog’s liver has six lobes. This is important because tumors or smaller liver nodules in dogs can develop in a single lobe or in multiple lobes. Other types of cancer also can metastasize (spread) to the liver. A liver tumor also can be benign (noncancerous). “Hepatic” means having to do with the liver; types of hepatic tumors in dogs include:
Hepatocellular carcinoma in dogs: Hepatocellular carcinoma (or hepatocellular adenocarcinoma) is the most common primary liver tumor seen in dogs. Typically, this solitary mass will arise in only one liver lobe. On occasion, this type of cancer can occur in many lobes of the liver, creating a more nodular appearance.
Sarcoma: A tumor within the liver also could be a sarcoma, such as a leiomyosarcoma or a fibrosarcoma. Other tumors can metastasize to the liver from another part of the body. Histiocytic sarcoma and hemangiosarcoma (tumors that arise in blood and blood vessel cells) are two examples.
Mast cell tumors: Though a common type of skin cancer in dogs, mast cell tumors can arise from or spread to multiple lobes of the liver.
Lymphoma: Cancer from the lymph nodes and lymphatic system also can spread to the liver. At times, lymphoma will arise in the liver first.
Benign tumors: Not every type of liver tumor in dogs is cancerous. Adenomas are generally benign, like cysts. In the case of a benign tumor growing in a single lobe of the liver, surgical removal is curative.
Clinical Signs to Look for
Because of the liver’s location and its various functions, signs of liver cancer in dogs can be both physical and behavioral. The liver sits near the end of the rib cage, and so a mass can make a dog look full or pot-bellied. However, many dogs with bigger bellies are just overweight, so this sign alone is not necessarily a cause for alarm. In terms of behavior, a dog with liver cancer may slow down and become lethargic. A tumor pushing on a dog’s stomach can also cause him or her to vomit or demonstrate a decreased appetite, resulting in weight loss. Because of the “full” feeling, a dog may also struggle to get up, similarly to if the dog has eaten too much. However, these can also be signs of other issues, not just liver cancer.
Workup and Diagnosis
Since liver cancer in dogs is rare and there are other causes for similar symptoms, you could expect a veterinarian to perform a series of diagnostic procedures before determining whether your dog has cancer. Bloodwork can determine whether liver enzymes are elevated and a full blood panel may include a CBC (complete blood count), chemistry profile and a coagulation profile (which measures clotting ability). Urinalysis is standard. If the presence of a tumor is suspected, a veterinarian may order chest X-rays to determine whether the cancer has spread to the lungs, an abdominal ultrasound and/or CAT scan to further assess the abdominal cavity, and perhaps an ultrasound-guided biopsy or aspiration of the tissue in question.
Treatment Options and Prognosis
While there is no cure for liver cancer, there are a range of treatment options that may restore your dog’s quality of life and significantly extend your time together.
Surgery: For canine hepatic cancer, surgical removal of the tumor is often the treatment of choice. A CAT scan can be used to help determine whether removal is feasible. Ideally, the tumor should affect only one liver lobe and not be involved with vital structures that cannot be excised. Dogs fare very well with only 5 liver lobes. After removal, dogs typically are feeling great within a week or two, and it may be a year or even a year and a half before cancer returns.
Stereotactic Radiation: If surgery is not an option or a pet parent declines that possibility for any reason, Stereotactic Radiation is an alternative. This is a newer treatment modality for liver cancer in dogs, but veterinarians are reporting good outcomes, with dogs doing well for quite a while. The goal of Stereotactic Radiation is to damage the tumor without harming surrounding tissues and organs. Three treatments are typical, and Stereotactic Radiation results in fewer side effects than chemotherapy. Tumors sometimes die quickly after radiation. Sometimes they slowly regress over the course of months. The PetCure Oncology team is qualified to provide Stereotactic Radiation and has extensive experience in providing this treatment option.
Chemotherapy: Since the liver is essential to life, there are scenarios under which surgical removal is not an option. The spread of a tumor to multiple liver lobes is one such scenario. In these types of cases, chemotherapy may be indicated, depending on the specific type of cancer. For instance, dogs with lymphoma respond well to chemotherapy; hemangiosarcoma is not as responsive.
No treatment: If a pet parent opts to decline treatment, subsequent decisions should be made based on the dog’s quality of life. Clinical signs will worsen, and a dog may drink more water and urinate more frequently. The timeframe depends on the type of liver cancer. Again, a single-lobe hepatic carcinoma is slow-growing; while a metastatic cancer that is left untreated can grow quickly in a couple to a few months.
Find a PetCure Oncology Location Near You
PetCure Oncology provides innovative treatments for liver cancer in dogs. You will find that we share your concerns for your dog’s health and are supportive and professional at all times. We are driven by our mission to prolong your dog’s life, and maintain his or her quality of life, for as long as possible.
For more information about PetCure Oncology and our treatment options, find a location near you today.