My dog has been diagnosed with primary hepatocellular carcinoma. The veterinarian found after exploratory surgery that the cancer is located too close to the vena cava to permit surgical excision. My dog is having chemotherapy treatments and so far she is tolerating them well. An ultrasound of the liver shows the tumor is not enlarging. Could you give me any information about primary hepatocellular carcinoma? I have had trouble finding out much about it. I heard it also occurs in cats and people.
I'm sorry that your dog has received this diagnosis, although it's nice to hear that she is tolerating the chemotherapy well. I'm assuming that a veterinary oncologist is supervising her treatment, either directly or indirectly. Such persons remain your best resource for contemporary information on the condition and treatment alternatives. Veterinary cancer textbooks list few treatment options for primary liver tumors. Treatments are limited in people as well.
Dogs, and less commonly cats, may develop primary hepatocellular carcinoma. Primary hepatocellular carcinoma is cancer that arises from uncontrolled growth of liver cells (hepatocytes). The cause is not known, but experimental exposure to several specific carcinogens (substances known to cause cancer) has resulted in the formation of these tumors. This type of liver cancer may develop as a single (solitary) tumor, or as multiple nodular tumors, or as many diffuse small growths. Generally, solitary tumors are less likely to metastasize, or spread, readily. Nodular liver cancer usually spreads, and diffuse growths almost always spread. Hepatocellular cancer most commonly spreads to the regional lymph nodes, lung and spleen.
Animals with large solitary liver lesions are less likely to experience metastasis; they are the preferred candidates for surgery, with the potential for long-term remission (greater than two years). However, most dogs with hepatocellular carcinoma will have multiple nodular or diffuse tumors; affected cats usually have diffuse ones.
Generally this cancer arises in older dogs and cats, usually over 10 years old. Male cats are more often affected than female cats, and domestic shorthairs are the most commonly affected breed of cat. Signs common to both species may include lethargy, weight loss, loss of appetite, vomiting excessive thirst, hepatomegaly (enlarged liver) and a palpable tumor if it is solitary or even nodular. Affected dogs may have bleeding disorders as a result of disruption of vitamin K-1 metabolism and may also develop low blood sugar and seizures. Jaundice may occur if the tumor occludes the biliary tree, causing bile to back up into the blood stream or if there is enough tumor mass to cause liver failure.
Diagnostic tests and procedures include bloodwork, radiographs (x-rays), ultrasonography, and liver biopsy. Many affected animals will have elevated liver enzymes in the blood. Dogs with coagulopathy (bleeding disorders) will have abnormal clotting tests. Liver biopsy, where a sample of the liver and tumor tissue is obtained, with ultrasound guidance or with surgery, allows microscopic analysis of the tissue to establish the final diagnosis of primary hepatocellular carcinoma.
Treatment and prognosis depend on the form of the cancer present. Solitary tumors are surgically excised and carry a fair to good prognosis. Nodular tumors may or may not be readily treated surgically and diffuse lesions are rarely if ever removed. The prognosis for inoperable nodular and diffuse tumors is poor.
Currently there is not a sufficient body of data available to evaluate the effectiveness of chemotherapy in these cases. Maintaining stable disease (no growth or metastasis) may be the most reasonable goal of chemotherapy. We wish you the best of luck with this difficult problem.
11/17/00
