Diagnosis
While sophisticated diagnostics, including body scans, can help to identify potential tumours, a sample of tissue from the suspected area is necessary for an accurate diagnosis of cancer. Small tumours may simply be removed, but for larger ones, your vet may either take a small piece of suspect tissue (a biopsy), or use a needle and syringe to withdraw a sample of cells to be analysed. Cancers generally occur later in life, but can also affect younger individuals. Early diagnosis is vital, and dogs over seven years old should have yearly preventative veterinary examinations.
Causes
Primary liver cancer is the result of a primary liver tumor (one that originates in the liver). The most common primary liver tumor is the hepatocellular carcinoma which usually does not spread to other parts of the body. Instead, the tumor invades into the liver tissue.
Primary liver cancer is less common than metastatic liver cancer in dogs. Primary liver cancer occurs more frequently in older dogs (10 years of age or older). There is a slightly increased risk of primary liver tumors in male dogs. Although rather rare, primary liver cancer in dogs can also metastasize to other parts of the body.
Metastatic, or secondary, liver cancer is one that has spread to the liver from other organs. Metastatic liver tumors are generally multiple nodules.
The liver is the largest organ in the dog's body, and it is involved in a large number of bodily functions and processes. In particular, the liver is one of the main organs responsible for detoxifying many toxic substances circulating in the body. It is understandable, therefore, that the liver is one of the primary targets of almost all metastatic cancers. Cancer that metastasizes tends to travel to the liver through the blood stream or the lymphatic system, and the fact that the liver is supplied blood through two blood vessels instead of one makes it all the more vulnerable. The cause of primary liver cancer may be related to environmental factors, such as exposure to cancer-causing chemicals (carcinogens). Examples of possible carcinogens include chemicals in some commercial pet food (food additives, artificial coloring and flavors), certain pesticides, dyes, etc.
Treatment
Treatment for cancer is pretty general for all forms. The vet will look at the size of the tumor and decide if surgery is an option. You may not want an invasive procedure as well. Keep in mind that if surgery is an option it usually is the best thing to do to help your dog feel better. If the mass is too large surgery will not be an option and the vet will recommend medication, radiation, and/ or chemotherapy. The medications and therapy are to help reduce the cancer cells as well as prevent more cells from forming. It is important to realize that radiation and chemotherapy can last for several treatments before you will see results. In some cases the cancer may be too far along to do much good. It is always best to help make the dog as comfortable as possible.
Prognosis
It is difficult to detect liver cancer in its early stages, and prognosis of the advanced stage is extremely poor.
