Learn what canine hepatocellular carcinoma (HCC) is, what the different subtypes are, which signs and symptoms may present, how canine HCC is diagnosed, and what to expect in terms of prognosis. Understanding this disease can help you make informed, compassionate decisions about testing, treatment, and comfort care in partnership with your veterinarian.
What Is HCCTypes of HCCSigns & SymptomsDiagnosisPrognosisHepatocellular carcinoma (HCC) is a cancer that begins in liver cells (hepatocytes). It’s considered “primary” liver cancer, meaning it starts in the liver rather than spreading there from another organ.1
While it is considered the most common primary liver cancer in dogs2, accounting for 35% to 60% of primary liver tumors3 and 50% to 77% of primary hepatobiliary tumors4, HCC is considered rare in dogs5 as primary liver tumors represent only about 0.6–1.5% of all canine tumors6.
Canine hepatocellular carcinoma is classically divided into three types: massive, nodular, and diffuse.2
Dogs with hepatocellular carcinoma (HCC) may remain asymptomatic, showing no symptoms at all, or they may exhibit clinical signs such as vomiting, diarrhea, increased thirst (polydipsia), increased urination (polyuria), abdominal distention due to fluid buildup (ascites), decreased appetite (inappetence/anorexia), weight loss, lethargy, seizures, and jaundice (yellowing of gums, eyes, or skin). Not all dogs display signs, and in some cases, HCC is discovered only incidentally during evaluation for another concern.1,10
Diagnosis of hepatocellular carcinoma (HCC) in dogs typically involves multiple steps. It may begin with a physical examination and bloodwork11, including measurements of liver enzymes such as ALT and ALP10, which can indicate liver injury12. Because bloodwork alone cannot definitively diagnose HCC, additional diagnostic tests are required, including imaging13. Radiographs and ultrasonography can evaluate the liver and detect masses14. When a mass is identified, tissue sampling may be pursued. This may be done via an ultrasound-guided fine-needle aspiration with cytology and/or a liver biopsy with histopathology.10,11,15
Prognosis for dogs with hepatocellular carcinoma (HCC) can vary widely and depends on several important factors. Tumor subtype and location within the liver play a significant role in determining available treatment options, including whether surgery or chemotherapy may be appropriate. Understanding how these factors influence outcomes can help set realistic expectations and support informed decisions about treatment and quality of life in collaboration with your veterinarian.
In a retrospective study, dogs whose tumors were surgically removed had a median survival time (MST) of more than 1,460 days.16 The massive subtype is generally considered amenable to surgical resection2, whereas the nodular and diffuse subtypes, which often involve multiple liver lobes, are usually not considered amenable to surgical treatment17.
Tumor location within the liver may influence surgical outcomes. In one study, dogs with HCC in the right middle liver lobe had an increased risk of death before discharge.2 Another study reported a 40% intraoperative mortality rate for dogs with right-sided liver tumors.16
Dogs managed conservatively without surgery had an MST of approximately 270 days in one study16, while in another study, dogs whose tumors were deemed unresectable and who only received a biopsy had an MST of 695 days2.
One study reported that in dogs with unresectable HCC, treatment with sorafenib (chemotherapy) resulted in a median overall survival time of 361 days, whereas dogs treated with metronomic chemotherapy had a median survival of 32 days.17