The diagnosis of liver cancer is somewhat challenging as there is both Primary liver cancer and Secondary liver cancer. Each of these have a similar appearance but widely different treatment and prognosis.
Most likely patient to develop primary liver cell cancer is a person with an underlying liver disease like cirrhosis or chronic (long standing) viral hepatitis. When your doctor suspects hepatocellular cancer, he requests a series of blood tests including a tumor marker called serum alpha-fetoprotein (AFP) level. In the presence of liver cell cancer there will be rising levels of this tumor marker. The second set of blood tests, called the liver function tests, examines the blood components closely related to the liver. The purpose of this blood test is to determine the overall health of the liver.
If the blood tests are abnormal the doctor will likely request imaging studies which have a major role in diagnosing liver cell cancer. Usually ultrasound scan is performed to see the liver and adjacent structures as the first step. It can detect masses in the liver by the use of sound waves which get converted into an image on a video screen. Serial ultrasound scans (every 6 months) become a very important screening tool to diagnose liver cancer early, in high risk patients. Ultrasound scan being performed by a doctor or technician, the images are on the screen.
The CT scan is another imaging modality which gives detailed cross-sectional images of the body using X-rays. A CT scan of the abdomen can identify and provide precise information about the size, shape, and position of any tumors in the liver. MRI scans also become very useful to identify liver tumors and it uses electromagnetic waves rather than x-rays to build up the image. Using MIRI scans, it is possible to differentiate between a liver cancer and a non-cancerous lesion in the liver.
When diagnostic imaging results are uncertain, a tissue sample can be taken from liver called biopsy. This can be done in several ways. Percutaneous biopsy is performed by placing a needle into the liver, via skin under local anesthesia. This can be done under ultrasound or CT guidance. Biopsy specimens can also be taken as laparoscopic biopsy. During this procedure, the person who takes the biopsy can see the liver and take samples of areas which look abnormal. The tip of the needle is placed where the abnormality is seen on the CT scan or ultrasound image. The needle is confirmed in the right position before any tissue is removed.
After the diagnosis, the full workup will be done to find out possible etiology (cause), how much remaining liver function, staging (to find the extent of the disease) and general condition of the patient for the purpose of establishing the best treatment plan. Hepatitis B and hepatitis C are the main causative agents for hepatocellular carcinoma and are critical to evaluation. The serum levels of specific antigens (parts of the virus which can make immune response in our body) and antibodies (molecules made by our immune system to fight against infection) are tested using a technique called radioimmunoassay to detect hepatitis B and C infection.
The assessment of liver function includes measurement of several serum markers. Serum levels of aspartate transaminase and alanine transaminase will be elevated when there is damage to liver tissue due to tumor invasion. There will be elevated alkaline phosphatase and bilirubin levels when there is obstruction to biliary system by the local growth of the cancer. Serum albumin and protein levels will be low due to reduced protein synthetic function of the liver. The tests to assess clotting function of blood including INR (International normalizing ratio) will often show clotting abnormalities due to impaired production of clotting factors by liver.
Staging of primary hepatocellular carcinoma is based on the results of the physical exam, imaging tests (ultrasound, CT or MRI scan) and sometimes results of surgery. Common sites of metastasis (distal spread) in liver cancer include the lung, lymph nodes in the abdomen and bone. Due to that reason, chest imaging and a bone scan are recommended in the initial workup. The stage of the cancer is critically important in selecting the mode of treatment and the duration.
Barcelona Clinic Liver Cancer (BCLC) system is a commonly used staging system for staging primary liver cancer. The BCLC system categorizes HCC based on characteristics of the tumor, liver function, performance status, and cancer-related symptoms. There are four stages categorized as follows.
Very early stage – The tumor is smaller than 2 cm. There is no increased pressure in the portal vein. Bilirubin levels are normal.
Early stage – The tumor is smaller than 5 cm. Liver function varies. There may be no increased pressure in the portal vein, increased portal vein pressure and normal bilirubin levels, or increased portal vein pressure and increased bilirubin levels.
Intermediate stage – The tumor may be large or there may be multiple tumors.
Advanced stage – The tumor has invaded the portal vein or spread to other parts of the body, such as the lungs and bones.
The general condition of the patient is assessed in determining optimal therapy. Useful studies may include a complete blood cell count (CBC); mainly to identify anemia and platelet levels, electrolyte levels and renal function tests (blood urea nitrogen and creatinine) for characterizing the patient’s clinical status and function of other systems.
Diagnosis of secondary liver cancer
If there is suspicion regarding metastatic or secondary liver cancer where the primary focus of the cancer is outside the liver the patient should have an extensive evaluation to search for the primary cancer. Main types of cancer that will metastasis to the liver are colon, rectum, breast, pancreas, stomach and lungs. The investigations target the primary site as the doctor suspects after taking the history and examination findings coorelated with the initial imaging studies and general laboratory tests.
For instances if the primary site is colon the patient may undergo colonoscopy according to the site where the lesion is suspected in the colon. Colonoscopy is an endoscopic procedure done under sedation (make you to go into sleep) while lying onto a side. In this procedure, a camera is passed from the anus into the colon via rectum and the lumen (inner cavity) of the colon and rectum is visualized on a video screen. If any suspicious area is found, a biopsy can be taken through the endoscope and sent to lab for microscopy. If the patient is suspected to have primary stomach cancer, endoscopy can be performed by passing the scope through the mouth and then the lumen of the esophagus, stomach and initial part of the small intestine can be visualized. There also biopsy studies can be performed to get the tissue diagnosis of the primary site. To exclude primary lung cancer, a chest radiography and spiral CT of the chest are performed and for primary breast cancer, mammography and ultrasound scans can be used for radiological diagnosis.
For secondary liver cancers, the staging will be done according to the primary site of the cancer and when the liver metastasis are found this almost always means that this is an advanced stage of the primary cancer.