Liver Cancer and Tumors in Dogs: Causes, Symptoms, Surgery, Treatments, and Tips for Improvement and RecoveryThe Power of Immunity to Overcome Liver Cancer

What Is Liver Cancer, Hepatocellular Carcinoma, and Liver Tumors in Dogs?

You may have heard it referred to as the “silent organ,” because liver cancer often does not present symptoms in its early stages, making it harder to detect early.

When these symptoms appear, liver cancer may already be in an advanced stage.

Types of Liver Cancer in Dogs – Hepatocellular Carcinoma

Primary Liver Cancer – Cancer in Dogs, Hepatocellular Carcinoma

There are mainly four types of primary liver cancer in dogs.

The most common is hepatocellular carcinoma, which accounts for about half of primary liver cancers.

Hepatocellular Carcinoma

Primary liver cancer in dogs is relatively uncommon among malignant tumors that develop in dogs.

Of primary liver cancers, hepatocellular carcinoma is a cancer that originates from hepatocytes (liver cells) rather than metastasizing from cancer in other organs.

Hepatocellular carcinoma in dogs is reported to be the most common primary liver tumor, often forming isolated mass lesions in a single lobe (part of the liver).

Therefore, the first-line treatment for hepatocellular carcinoma is surgical removal. If the tumor can be completely excised through surgery, the prognosis is relatively favorable.

However, it is not easy to detect hepatocellular carcinoma early.

One reason is that the liver is a very large organ. Additionally, it has a high reserve and regenerative capacity, so by the time liver cell cancer is detected due to “abnormalities in the dog’s condition,” the tumor is often already large.

A lot of blood flows through the liver, and if the cancer infiltrates the hepatic veins, portal veins, or vena cava, it becomes very difficult to remove the tumor surgically.

Intrahepatic Cholangiocarcinoma

It is rare for dogs to develop intrahepatic cholangiocarcinoma, but it can cause jaundice due to bile flow congestion and can lead to diarrhea, constipation, or other abnormalities in stool condition.

A few years ago, actress Naomi Kawashima passed away from this type of cancer.

Because it is a highly invasive cancer, even if it is detected early and surgically removed, there are many cases where it recurs or metastasizes.

Additionally, it is generally said that intrahepatic cholangiocarcinoma has a poor prognosis because it responds poorly (or hardly at all) to chemotherapy.

Hemangiosarcoma

Hemangiosarcoma is a troublesome type of cancer that can develop anywhere as long as there are blood vessels. Because it develops within blood vessels, it is also a disease that tends to metastasize.

The liver is an organ where a lot of blood flows, and hemangiosarcoma often occurs in the liver. If a hemangiosarcoma grows large, it can rupture, causing massive bleeding and potentially leading to death.

Additionally, in general, the prognosis for hemangiosarcoma is not good.

Leiomyosarcoma

When we think of muscles, we often think of the skeletal muscles used for movement in the arms and legs, but muscles are also necessary for moving blood vessels and internal organs; these are called smooth muscles.

Smooth muscles are found throughout the body, so leiomyosarcoma can develop in various locations.

Carcinoid & Neuroendocrine Tumors

Since carcinoids are highly metastatic cancers, it is not uncommon for them to have already metastasized to other organs by the time they are discovered.

Metastatic Liver Cancer – Cancer and Liver Tumors in Dogs

For instance, cancers originating in the stomach, intestines, gallbladder, bile ducts, and pancreas can sometimes metastasize to the liver. Additionally, mammary gland tumors (breast cancer) and lung cancer can also metastasize to the liver.

Liver metastasis is also commonly observed with hemangiosarcoma, lymphoma, multiple myeloma, mast cell tumors, and melanoma.
When tumors from other organs metastasize to the liver, it is called metastatic liver cancer.

Causes of Liver Cancer – Liver Cancer in Dogs

Causes of Primary Liver Cancer

In humans, many cases are caused by hepatitis viruses such as Hepatitis B or C. However, in dogs and cats, it is known that chemical substances can cause inflammation in liver cells leading to cancer.

The liver functions as a chemical factory that detoxifies toxins within the body.

When carcinogenic substances like pesticides, drugs (chemotherapy agents, antibiotics, long-term use of steroids), preservatives, colorings, additives, paints, chemicals, exhaust gas, detergents, and other harmful agents enter the body, the liver works hard to neutralize these toxins.

However, if these carcinogenic substances chronically enter the body, the liver can become inflamed.
Chronic irritation and inflammation increase the risk of liver cancer development.

There are reports that cigarette smoke increases the incidence of cancer in dogs and cats, so caution is necessary in households with smokers.

While not all exposures to these chemicals result in cancer immediately, it is advisable to avoid long-term exposure to such chemical substances.

Causes of Metastatic Liver Cancer

The causes of metastatic liver cancer vary depending on the primary cancer (the original cancer).
If there is a stagnation of blood flow or a low body temperature, metastasis can occur more easily, so it is important to keep the body warm.

Liver Cancer Diagnosis – Liver Cancer in Dogs

The following tests are included in the examination:

It is difficult to diagnose liver disease based solely on a medical interview because liver cancer and other liver diseases often do not show clear symptoms.

If blood tests show abnormal (high) values for ALP, AST (GOT), ALT (GPT), γGTP, etc., there may be some disease in the liver, so imaging tests (such as ultrasound) are recommended.

However, sedatives may be required for imaging tests, so it’s recommended to discuss with your veterinarian if the tests are truly necessary.

Treatment of Liver Cancer – Liver Cancer in Dogs

Liver cancer can be completely cured when the cancer can be entirely removed through surgery.

If the cancer forms a mass, is not invasive, and is limited to a single liver lobe, the prognosis after surgery is good, so it is worth actively considering surgery.

On the other hand, if the cancer is invasive or spreads to multiple liver lobes, even if it seems to be cleanly removed, there is often residual cancer at the cellular level, causing rapid recurrence. Therefore, many cases are not suitable for surgery.

Intrahepatic cholangiocarcinoma is highly invasive, and recurrence and metastasis occur frequently and shortly after surgery, resulting in a poor prognosis.

Of course, if cancer has spread extensively, surgery is not indicated.

Carcinoids are also a type of aggressive cancer that easily metastasizes to lymph nodes, peritoneum, lungs, etc., from an early stage, generally making them unsuitable for surgery.

Surgery – Liver Cancer in Dogs

There are two types of surgery: curative surgery and palliative surgery.

For localized mass-type hepatocellular carcinoma, long-term survival can be expected after resection, so surgery should be actively considered.

On the other hand, if cancer is widespread or invasive in multiple liver lobes, extensive resection of the liver (expansive surgery) is required, placing a significant burden on the body.

Even if cancer appears to be resected, there is a high possibility of recurrence within a short period, thus careful consideration is required to determine if surgery is the best option.

It’s recommended to thoroughly discuss with your veterinarian whether surgery is appropriate.

Chemotherapy – Liver Cancer in Dogs

Chemotherapy may also be used to treat liver cancer in dogs. However, it is important to remember that chemotherapy aims to temporarily shrink the cancer rather than cure it.

There are animal hospitals that perform treatments such as hepatic artery embolization and liver intra-arterial chemotherapy, but in any case, it is difficult to completely cure cancer with chemotherapy.

If chemotherapy is recommended, we strongly suggest that you thoroughly check whether the expected therapeutic effects and side effects will not deteriorate the QOL (quality of life) and then decide whether to proceed with the treatment or not.

Radiation Therapy for Canine Liver Cancer

It can be used in combination with surgery or as a standalone treatment.

However, the response to radiation varies from individual to individual, and since the treatment requires general anesthesia, the burden on the body from the anesthetics is unavoidable.

For elderly dogs or dogs with lung diseases, the risks associated with anesthesia increase, so careful consideration is essential.

Precautions When Undergoing Liver Cancer Treatment in Dogs

Both surgery, chemotherapy, and radiation therapy have their merits and demerits.

The person who knows your dog’s condition best is you, the owner.

“I treated my pet because the vet told me to, but the treatment made the condition worse, and the suffering increased.”
We recommend that you, as the owner’s principal, decide whether to proceed with, pause, or forgo treatment for your beloved pet to prevent such situations.

If you decide to proceed with chemotherapy, please consider managing side effects with Cordy for immune support and Placenta extract derived from domestic SPF pigs for liver and kidney care.