Liver Cancer in Dogs - Symptoms, Diagnosis, and Treatment
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Tumors are one of the many pathologies that can affect the liver of dogs. Although primary liver tumors are not common in dogs, the liver is one of the organs where malignant tumors arising in other parts of the body most often metastasize. Liver cancer can be a silent killer in dogs because obvious clinical signs are not always apparent.
In the following AnimalWised article, we discuss liver cancer in dogs, its symptoms, and treatment.
Types of liver cancer in dogs
Before we explain the different types of liver cancer that can affect dogs, it is important to briefly clarify the difference between the terms "tumor" and "cancer."
Depending on their biological behavior, tumors can be benign or malignant:
- Benign tumors: they have a low capacity for local invasion and metastasis.
- Malignant tumors: They have a high capacity for local invasion and variable metastasis.
Usually, the term "cancer" is used to refer to a malignant tumor. Therefore, it could be concluded that "malignant tumor" and "cancer" are synonymous terms. In dogs, malignant liver tumors, i.e., liver cancer, are the most common. However, in this article, we will discuss both benign and malignant tumors.
After this clarification, we can now explain the types of liver tumors that can affect dogs. In general, liver tumors in dogs can be divided into two broad groups:
- Primary liver tumors: these arise in one of the tissues that make up the liver, i.e., the hepatocytes, bile ducts, connective tissue, or blood vessels.
- Secondary or metastatic liver tumors: when a tumor present in another area of the body metastasizes to the liver.
The different types of primary and secondary liver tumors are explained in more detail below.
Primary liver tumors are rare in dogs. In fact, they account for only between 0.6-1.3% of all neoplasms (abnormal and excessive growth of tissue) in dogs. Depending on the tissue from which tumor growth originates, the following primary liver tumors may be considered:
- Originating in the hepatocytes: there is hepatocellular adenoma (benign tumor) and hepatocellular carcinoma (malignant).
- Origin in the bile ducts of the liver: cholangiocellular adenoma (benign tumor) and cholangiocellular carcinoma (malignant tumor).
- Origin in connective tissue: fibrosarcoma (malignant tumor).
- Origin in blood vessels: hemangioma (benign tumor) and hemangiosarcoma (malignant tumor).
As we mentioned earlier, malignant liver tumors are more common in dogs. In addition, liver cancer is more common in older dogs. Specifically, hepatocellular carcinoma is the most common liver cancer in dogs, followed by cholangiocellular carcinoma.
Secondary or metastatic tumors
The liver, along with the lungs, is one of the organs to which malignant tumors arising in other parts of the body most frequently metastasize. Malignant tumors that can metastasize to the liver include:
Symptoms of liver cancer in dogs
As with most liver diseases, animals initially remain asymptomatic. As the tumor progresses, nonspecific signs such as vomiting, diarrhea, polyuria, polydipsia, anorexia, weight loss, apathy, and/or depression may occur.
Once the functional reserve capacity of the liver is exceeded, clinical signs suggestive of liver disease occur, including:
- Abdominal distension: this can occur for two reasons, enlargement of the liver and ascites. Ascites is the presence of free fluid in the abdomen that occurs when the liver is unable to maintain albumin levels in the blood.
- Jaundice: yellowish discoloration of the mucous membranes caused by an excess of bilirubin (yellow pigment) deposited in the tissues. In dogs, it usually first appears on the sclera. For more information about Jaundice in dogs, see this other article.
- Hepatic encephalopathy: It is a neurological picture that results from the accumulation of neurotoxic substances in the blood that are not metabolized by the liver, mainly ammonia. Signs that may occur in these dogs include an altered state of consciousness (lethargy, stupor and eventually coma), weakness or ataxia, pressure of the head against the wall or floor, circling and seizures. To learn more, read this post about Hepatic encephalopathy in dogs.
- Hemorrhages: they result from a decrease in the synthesis of clotting factors, platelet function and absorption of vitamin K.
Diagnosis of liver cancer in dogs
The diagnostic protocol for liver tumors in dogs should follow the following points:
- Clinical history and general examination: look for clinical signs suggestive of liver disease. Examination of the abdomen may show that it is enlarged.
- Blood tests: levels such as total proteins, albumin, liver enzymes, ammonia, glucose, and bile acids should be measured.
- Diagnostic imaging: this can be done by x-ray or ultrasound of the abdominal cavity. X-ray can show if the liver is enlarged and if the abdominal organs have moved backward. MRI is also recommended to better guide surgery and detect possible metastases to other organs.
- Biopsy and histopathological analysis: The sample can be obtained percutaneously (with biopsy needles) or surgically (by laparotomy or laparoscopy). Histopathological analysis allows a definitive diagnosis to be made and the specific type of liver tumor to be determined.
Prevention of liver cancer in dogs
The causes of liver cancer in dogs are not known with certainty, making prevention and early detection of the disease extremely challenging.
Usually, liver tumors begin with mild and nonspecific symptoms, and only in advanced stages do signs suggestive of liver disease appear. This makes early diagnosis difficult. Often, the cancer is diagnosed at advanced stages where local invasion has already occurred, including regional or distant metastases.
In this other AnimalWised article, you will learn more about the causes, symptoms, and possible treatment of liver failure in dogs, so you can act as early as possible.
Treatment of liver cancer in dogs
Different types of liver tumors in dogs require different treatments. There are mainly two options:
- Surgical treatment should be chosen for single nodular tumors, especially resection of the tumor. Since the liver of dogs contains bacteria under normal conditions, a possible complication after surgery is the occurrence of an abscess caused by these bacteria. To avoid this complication, it is recommended to administer broad-spectrum antibiotics after tumor resection.
- In multifocal nodal tumors, that is, when there are multiple nodules in the liver, or in diffuse nodules, surgery cannot be performed, so other treatments such as chemotherapy or radiotherapy must be used.
For more information on this topic, continue reading this AnimalWised article on chemotherapy in dogs.
Diet for dogs with liver cancer
Good nutritional management is essential in dogs with liver cancer to maintain their physical condition. In general, a diet should be offered:
- Highly digestible
- Rich in easily assimilated carbohydrates
- Low in fat
Continue reading this other article to learn more about the different types of healthy and balanced diets for dogs.
Life expectancy for dogs with liver cancer
The prognosis of liver cancer in dogs can vary depending on the specific type of tumor. Not surprisingly, dogs with benign tumors have a better prognosis and longer life expectancy than dogs with malignant tumors.
However, it is important to know that there are significant differences in the prognosis of different types of liver cancer in dogs:
- Cholangiocellular carcinoma: is the liver cancer in dogs with the worst prognosis, as it is highly prone to metastasis (between 80-87% of cases metastasize). Despite surgical resection, survival is usually short due to metastasis and recurrence of the tumor in the liver.
- Hepatocellular carcinoma: Prognosis varies depending on the form in which it occurs. If it has a nodular appearance, especially if it is a single mass involving the left lobe of the liver, the prognosis is good. After surgery, dogs have a long survival time and a low rate of metastasis. However, when these tumors diffusely affect the liver, the prognosis worsens significantly.
Continue reading this article if you want to learn more about the different types of cancer in dogs.
This article is purely informative. AnimalWised does not have the authority to prescribe any veterinary treatment or create a diagnosis. We invite you to take your pet to the veterinarian if they are suffering from any condition or pain.
If you want to read similar articles to Liver Cancer in Dogs - Symptoms, Diagnosis, and Treatment, we recommend you visit our Other health problems category.
- Buracco, P. (2014). Diagnosis and treatment of the most important gastrointestinal tumors (stomach, small and large intestine, and liver) in dogs and cats. XIV National Congress of AVEACA.
- Buriticá, E., Barbosa, X., Echeverry, D. (2009). Canine hepatocellular carcinoma: a case report. MVZ magazine; 14(2)