Primary liver tumors in dogs

Surprisingly, hepatocellular carcinoma can carry a favorable prognosis, despite the sometimes huge size of some of these tumors. In dogs, malignant liver tumors outnumber benign tumors in which hepatocellular and biliary carcinomas are the most common primary liver tumors. They tend to occur in older animals (10-11 years old) and males are more commonly affected than females. The cause of liver tumors is unknown in dogs: the liver functions to detoxify mutagenic (potentially cancer causing) compounds and this may render the hepatobiliary system more susceptible to their effects. Liver tumors present in three different forms: solitary (massive), nodular and diffuse. Hepatocellular carcinomas most commonly present in the solitary (massive) form.

The treatment of choice for solitary masses is surgery. Seventy-five percent of the liver can be surgically removed and the liver will regenerate to complete functional levels in 6-8 weeks. Chemotherapy is reserved for high grade solitary tumors or the diffuse/nodular forms, but is often not effective. For dogs with massive (solitary) hepatocellular carcinomas metastatsis is less common and tumor regrowth is slow. One recent study of 48 cases of hepatocellular carcinomas reported a metastatic rate of only 4.8%. Reported survival times for massive hepatocellular carcinomas are > 1,460 days in which the ability to perform surgery was the main prognostic factor. In this study, no further treatment beyond surgery was pursued or recommended. JAVMA Liptak et al. Oct. 15, 2004.

Dr. Walshaw has removed quite a few extremely large liver tumors at our practice with excellent outcomes for the patients! If you do an ultrasound and find a massive tumor, it doesn't mean we can't help that patient!