What is Liver and Gallbladder Cancer in Dogs?
Liver and gallbladder cancer are conditions that can affect dogs similarly to humans. The liver, a vital organ responsible for metabolism and blood filtration, along with the gallbladder, which stores bile for digestion, are both susceptible to cancerous growths in dogs.
Dogs may experience cancer in either the liver or the gallbladder, but it’s not uncommon for them to develop tumors in both organs simultaneously due to their close proximity and interdependent functions.
The liver in dogs consists of six lobes, with the gallbladder nestled between them. Positioned in the abdominal cavity beneath the diaphragm, the liver and gallbladder are adjacent to the stomach and pancreas.
Veterinarians categorize these tumors based on various factors:
- Benign tumors, which are non-cancerous.
- Malignant tumors, which are cancerous.
- Primary tumors, originating within the liver or gallbladder.
- Secondary tumors, which have spread from another primary tumor elsewhere in the body.
- Focal tumors, localized to one specific area.
- Diffuse tumors, which have spread extensively throughout the entire organ.
Benign Liver Tumors
Benign liver tumors, although non-cancerous, can often be mistaken for malignant tumors, prompting veterinarians to recommend further tests to rule out more serious conditions when they discover any liver tumor in animals. These benign growths do not metastasize or spread to other parts of the body and thus do not pose a risk of metastasis. With early detection, many benign tumors can be removed, offering dogs a positive prognosis. They can manifest as focal, confined to one area or lobe, or diffuse, spreading across multiple lobes. Examples of such benign liver and gallbladder tumors encompass hepatocellular adenoma, hepatoma, nodular hyperplasia, bile duct adenoma, and hemangioma.
Malignant Liver Tumors
When it comes to malignant liver tumors, unlike benign ones with a typically positive prognosis if caught early, the outlook is not as favorable. The prognosis for malignant tumors depends on the aggressiveness of the cancer in the dog. Malignant tumors can either be primary, originating in the liver and gallbladder, or secondary, resulting from metastasis from distant tumors. Primary malignant liver and gallbladder tumors encompass hepatocellular carcinoma (the most common), cholangiocellular carcinoma, hemangiosarcoma, histiocytic sarcoma, fibrosarcoma, hepatic carcinoid, and lymphoma. Secondary malignant liver tumors, originating from other primary cancers, such as lymphoma, intestinal carcinoma, renal carcinoma, mast cell tumors, hemangiosarcoma, islet cell carcinoma, and exocrine pancreas carcinoma, are more prevalent than primary malignant liver tumors.
Symptoms
Identifying clinical indications of liver cancer in dogs can pose challenges due to their nonspecific nature or potential absence. However, if your dog exhibits signs of illness, symptoms may manifest as:
- Lethargy
- Reduced appetite
- Vomiting
- Diarrhea
- Low blood sugar, presenting as weakness, poor coordination, or lethargy
- Weight loss
- Presence of ascites (abnormal abdominal fluid)
- Increased thirst
- Frequent urination
- Enlarged liver
- Abdominal discomfort
- Jaundice or icterus (yellowing of skin and mucous membranes)
- Sudden collapse and shock due to tumor rupture.
Causes
The exact causes of liver and gallbladder cancer in dogs remain largely uncertain. However, genetics might contribute to its development. Female dogs may have a higher susceptibility to bile duct carcinomas, whereas hepatocellular carcinomas may be more common in male dogs. Hepatocellular carcinoma could be more prevalent among dogs with a history of chronic liver inflammation or damage. Certain breeds like German Shepherds, Labrador Retrievers, and Golden Retrievers exhibit a heightened incidence of hemangiosarcoma.
Diagnosis
Veterinarians can detect tumors or abnormal fluid accumulation during an abdominal examination of the dog. Additionally, they may observe yellowing of the mucous membranes. However, confirming a diagnosis of liver or gallbladder cancer typically necessitates further diagnostic procedures.
Blood Chemistry and Complete Blood Count Testing
Blood tests including complete blood count and blood chemistry are crucial in diagnosing liver or gallbladder cancer in dogs. A complete blood count may show a reduction in red blood cell count and alterations in platelet levels. Blood chemistry analysis may unveil changes indicative of liver and gallbladder cell damage, bile stasis, and liver insufficiency. Typically, veterinarians observe elevated levels of liver- and gallbladder-specific blood markers. However, it’s important to note that the severity of blood changes may not always correspond directly with the severity of the disease.
Bile Acid Testing
Bile acid testing is conducted to evaluate liver function, and the results might deviate from normal in dogs with liver cancer. This test measures bile acid levels before and after a fatty meal to gauge the liver’s ability to process bile acids effectively. Dogs with compromised liver function may exhibit abnormal processing of bile acids, leading to elevated test results.
Coagulation Testing
Testing for coagulation assesses the liver’s involvement in blood clotting. Fluctuations in liver function can directly affect a dog’s clotting ability.
Alpha-Fetoprotein (AFP)
Alpha-Fetoprotein (AFP) is a protein synthesized by youthful, regenerating, or cancerous liver cells. It serves as an indicator of significant liver ailments but doesn’t offer a conclusive diagnosis of a particular cancer type.
X-rays
Radiographs serve as valuable tools in assessing the size, shape, and positioning of the liver relative to surrounding abdominal organs. They also enable the detection of evident masses within the liver and other abdominal structures, along with abnormalities such as calcification. Additionally, veterinarians utilize X-rays to examine the lungs for indications of metastatic cancer.
Ultrasound
Ultrasound imaging provides a comprehensive examination of the internal composition of the liver and neighboring abdominal organs. Veterinary radiologists meticulously assess the entirety of the abdominal cavity for tumors, irregularities, and fluid accumulation. Additionally, veterinarians rely on ultrasound as a navigational tool during biopsy procedures, offering a definitive means of diagnosis.
Advanced Imaging
Advanced imaging techniques such as MRI (Magnetic Resonance Imaging) and CT (Computerized Tomography) scans play a crucial role in identifying the precise location, dimensions, and extent of cancers within the abdominal cavity. These scans can occasionally provide insights into the potential type of cancer based on specific characteristics observed. Utilizing advanced imaging aids in surgical staging by offering comprehensive visualization of the tumor and its interactions with the surrounding normal abdominal structures.
Surgery
Surgical procedures are employed by veterinarians to excise tumors or conduct biopsies on tumors that cannot be fully removed via surgery. Normally, prior to surgery, a dog will have undergone at least blood work, X-rays, and ultrasound examinations.
Treatment
Surgery
For dogs diagnosed with primary tumors of the liver or gallbladder, surgery stands as the primary treatment option. However, secondary tumors typically render surgery unfeasible due to the advanced spread of cancer throughout the body.
The liver boasts remarkable regenerative capabilities, allowing dogs to undergo the removal of a significant portion of the liver while still maintaining or recovering function.
Tumors confined to a single liver lobe are more straightforward to excise compared to those affecting multiple lobes. Additionally, veterinarians can perform complete gallbladder removal when necessary. Often, the nature and location of the tumor necessitate the removal of both the gallbladder and sections of the liver.
Before proceeding with surgery, a comprehensive work-up, including cancer staging, is essential to assess overall health and cancer dissemination. This evaluation may encompass blood tests, chest X-rays, and abdominal ultrasounds. Based on the outcomes of these examinations, veterinarians will determine the suitability of a patient for surgical intervention.
Chemotherapy
Following the excision of a liver and gallbladder tumor or in cases of unresectable tumors, dogs may qualify for chemotherapy. Additionally, chemotherapy could be considered as a treatment option for addressing more advanced malignant secondary tumors.
Medication
While there is no medication that can cure liver or gallbladder cancer.
Prognosis of Liver Cancer and Gallbladder Cancer in Dogs
Prognoses for liver and gallbladder cancer in dogs vary depending on diagnosis. Generally, benign tumors offer a favorable prognosis, especially if discovered incidentally and the pet remains asymptomatic, with a good chance of a full life expectancy.
However, for patients with additional secondary conditions, the prognosis becomes more guarded. Malignant tumors, particularly those spreading to multiple nodules in the liver, carry a more uncertain outlook. In contrast, large single cancers may offer a better prognosis, especially if surgical resection is feasible, potentially extending life expectancy by a few years.
Mesenchymal and neuroendocrine tumors generally present a worse prognosis compared to hepatocellular tumors, with life expectancy ranging from weeks to months. Gallbladder cancer, characterized by a high metastatic rate, poses greater challenges for removal compared to liver tumors.
Unfortunately, not all tumors are operable, and when left untreated, they may grow to the point of rupture. Liver tumors, in particular, are fragile and vascular, and signs of rupture in dogs typically include lethargy, collapse, pale gums, and an increased heart rate. Immediate veterinary care is crucial if any of these symptoms are observed in a dog.
Living and Management
The recovery and management process for liver and gallbladder cancer in dogs depend on the treatment administered and the type of tumor present. Treatment typically involves addressing symptoms, such as providing liver function supplements, antibiotics for infections, and blood products to aid coagulation if necessary. Dogs undergoing partial liver removal may require more intensive post-operative care compared to those having their gallbladder removed, who may only need low-fat diets.
Following surgery, dogs will need standard post-operative care, including monitoring the incision site and managing pain. Typically, the incision spans from the sternum to the pelvis. During the initial 10 to 14 days post-surgery, dogs should limit activity, and their incisions should be monitored closely. Follow-up appointments with surgeons and oncologists are usually scheduled for two weeks after surgery and then every one to three months thereafter, depending on the treatment plan.
During these check-ups, veterinarians will assess bloodwork parameters, conduct X-rays, and perform ultrasounds to monitor disease progression and assess the dog’s quality of life.
Liver and Gallbladder Cancer in Dogs FAQs
How long do dogs live with liver cancer?
The life expectancy of dogs with liver cancer varies depending on the type of cancer. While some dogs may live for years after diagnosis, the survival rate is significantly lower in more severe cases.
Is a dog with liver cancer in pain?
Dogs with liver cancer may exhibit signs of lethargy, nausea, and tenderness in the abdomen, depending on the specific disease.
How fast does liver cancer progress in dogs?
Liver cancer progression can vary, ranging from weeks to years, depending on the type of cancer.