Blood Tests for the Diagnosis of Liver Cancer

Blood tests are a routine part of liver cancer care. They help doctors with diagnosis, planning treatment and monitoring progress over time. Although a single blood test cannot diagnose liver cancer, understanding the purpose and results of these tests is important. With this knowledge, you can actively participate in treatment decisions.

For liver cancer care, blood tests aid in:

• Diagnosing liver cancer via cancer markers such as alpha-fetoprotein (AFP) or des-gamma-carboxy prothrombin (DCP)
• Understanding the cause or risk factors of liver cancer, such as viral hepatitis and other indicators of abnormal liver function
• Assessing liver function, though tests measuring bilirubin, albumin, ALT, and AST, which help determine what treatments are safe
• Evaluating general health and how well other organs are working, which also affects the treatment plan
• Monitoring how well a patient responds to liver cancer treatments
• Detecting potential signs of cancer recurrence after treatment

Still, blood tests have limits (for example, AFP levels can appear normal in some liver cancers), and they are always interpreted together with imaging and sometimes biopsy results.

Understanding their role can help you take part in treatment decisions confidently.

Can liver cancer be detected through a blood test? No, a single blood test cannot diagnose liver cancer. These tests may be part of routine health examinations. When the results look suspicious, doctors may order further evaluation depending on a person’s signs and symptoms. This could lead to the discovery of liver cancer.

Could you have liver cancer even with normal blood test results? Yes, it is possible. For example, less than 20% of patients with early-stage liver cancer exhibit abnormal AFP levels, a tumor marker for liver cancer.

The AFP test measures alpha-fetoprotein, a protein produced during early pregnancy. Higher-than-normal AFP levels can sometimes be a sign of liver cancer, but they may also occur in other liver diseases such as hepatitis, cirrhosis or even certain non-cancerous tumors.

Generally, an AFP level of 20 ng/mL is taken as a benchmark to prompt further evaluation for liver cancer. If AFP levels exceed 400 ng/mL and a lesion is visible on the ultrasound, imaging (CT scan and/or MRI) is required, as it is highly likely to be liver cancer.

However, the AFP test alone is not sufficient for diagnosing liver cancer (up to 1 in 3 patients with liver cancer never have an elevated AFP). For this reason, AFP results are always combined with imaging tools, such as a CT scan, MRI or tumor biopsy, to confirm the diagnosis of liver cancer.

The AFP test can also help guide treatment decisions. A decrease in AFP levels typically indicates that treatment is working well. Conversely, a rise in AFP levels after treatment may suggest the cancer has returned or progressed, prompting further tests

Doctors often order additional blood tests alongside the AFP test. While these tests do not target specific cancer markers, they help monitor liver health and guide liver cancer treatment decisions.

Liver function tests (LFTs)

LFTs measure liver enzymes and proteins that reflect liver health and functionality. Liver cancer often develops from long-term liver diseases like hepatitis B or C, alcohol-related damage or fatty liver. These conditions can result in the formation of scar tissue (cirrhosis), which affects liver function.

Many treatment options for liver cancer, especially in advanced cases, depend heavily on how well the liver is functioning. If cirrhosis is so severe that major parts of the liver are not functioning, surgery to remove liver cancer may not be a good choice. Other aggressive treatments, such as certain targeted therapies and chemotherapy, may also be suitable if the liver is too weak to handle them.

Complete blood count (CBC)

The liver plays a role in blood cell processing by

• Producing hormones needed for blood cell formation
• Breaking down old or damaged red blood cells and recycling their components
• Excreting the by-products of blood cell breakdown through bile

A CBC measures the levels of different blood cells, such as red and white blood cells, as well as platelets. Liver diseases, cancer and certain cancer treatments can cause blood cell levels to fall outside their normal range.

Blood clotting tests

The liver makes proteins that help blood clot. Blood clotting tests assess the ability of the liver to make these proteins. If blood takes longer than normal to clot, that may indicate impaired liver function.

The readings on blood clotting tests, such as prothrombin time (PT) and INR, are part of the Child-Pugh score. This score measures liver health, and a high score means the liver is damaged. In such cases, surgery to remove liver cancer may not be safe because the remaining liver may not be healthy enough to support the body.

Kidney function tests

These tests measure creatinine and blood urea nitrogen (BUN) levels to check kidney health. The kidneys and liver work together to filter and detoxify the blood. Kidney health has a major impact on liver function and the overall treatment plan, including the administration of chemotherapy.

Kidney function is a key factor in the MELD score, which stands for “Model for End-Stage Liver Disease”. The MELD score helps prioritize patients for liver transplant. A higher MELD score means the liver is in worse condition, and the need for a transplant is more urgent. For many liver cancer patients, a transplant can treat both the cancer and the underlying liver disease.

Blood chemistry tests

Blood chemistry tests measure the levels of various substances in the blood, some of which can be affected in the presence of liver cancer. The liver plays a key role in regulating calcium, glucose and cholesterol levels in the body. When the liver function is impaired, the levels of these substances may fall outside their normal range.

Viral hepatitis tests

These tests check for the presence of viral infections such as hepatitis B and C. These viruses cause liver inflammation. Chronic infection increases the risk of liver cancer over time.

Navigating the complexities of liver cancer requires a comprehensive approach. Blood tests are invaluable tools in this process. You can approach your cancer journey with greater clarity by staying informed about your blood test results. Remember, your proactive involvement in health monitoring can make a significant difference in your treatment journey.