Liver Cancer (cont.)

In theory, a definitive diagnosis of liver cancer is always based on microscopic (histological) confirmation. However, some liver cancers are well differentiated, which means they are made up of nearly fully developed, mature liver cells (hepatocytes). Therefore, these cancers can look very similar to non-cancerous liver tissue under a microscope. Moreover, not all pathologists are trained to recognize the subtle differences between well-differentiated liver cancer and normal liver tissue. Also, some pathologists can mistake liver cancer for adenocarcinoma in the liver. An adenocarcinoma is a different type of cancer, and as previously mentioned, it originates from outside of the liver. Most importantly, a metastatic adenocarcinoma would be treated differently from a primary liver cancer (liver cancer). Therefore, all of this considered, it is important that an expert liver pathologist review the tissue slides of liver tumors in questionable situations. New advances in immunohistochemistry (staining the microscopic cells with proteins that identify cell types very specifically) have helped to be able to tell the difference among cell and cancer types more reliably.

Tissue can be sampled with a very thin needle. This technique is called fine needle aspiration. When a larger needle is used to obtain a core of tissue, the technique is called a biopsy. Generally, radiologists, using ultrasound or CT scans to guide the placement of the needle, perform the biopsies or fine needle aspirations. The most common risk of the aspiration or biopsy is bleeding, especially because liver cancer is a tumor that is very vascular (contains many blood vessels). Extremely rarely, new foci (small areas) of tumor can be seeded (planted) from the tumor by the needle into the liver along the needle track.

The aspiration procedure is safer than a biopsy with less risk for bleeding. However, interpretation of the specimen obtained by aspiration is more difficult because often only a cluster of cells is available for evaluation. Thus, a fine needle aspiration is not generally recommended. Moreover, a core of tissue obtained with a biopsy needle is more ideal for a definitive diagnosis because the architecture of the tissue is preserved. The point is that sometimes a precise diagnosis can be important clinically. For example, some studies have shown that the degree of differentiation of the tumor may predict the patient's outcome (prognosis). That is to say, the more differentiated (resembling normal liver cells) the tumor is, the better the prognosis.

All of that said, in many instances, there is probably no need for a tissue diagnosis by biopsy or aspiration. If a patient has a risk factor for liver cancer (for example, cirrhosis, chronic hepatitis B, or chronic hepatitis C) and a significantly elevated alpha-fetoprotein blood level, the doctor can be almost certain that the patient has liver cancer without doing a biopsy. Moreover, recent advances in MRI interpretation can identify small liver cancers as such with an extremely high degree of probability. However, recent understanding of gene variations in some liver cancers is beginning to be useful in helping to decide what kind of therapy might be best for an individual patient. Therefore, the patient and physician should always ask two questions before deciding on doing a liver biopsy:

1. Is this tumor most likely a liver cancer?

2. Will the biopsy findings change the management of the patient?

If the answer to both questions is yes, then the biopsy should be done. Finally, there are two other situations related to liver cancer in which a biopsy may be considered. The first is to characterize a liver abnormality (for example, a possible tumor) seen by imaging in the absence of risk factors for liver cancer or elevated alpha-fetoprotein. The second is to determine the extent of disease when there are multiple areas of abnormalities (possibly tumors) seen by imaging in the liver.

Overall, no blanket recommendation can be given regarding the need for liver biopsy or aspiration. The decision has to be made on an individual basis, depending on the treatment options and the expertise of the medical and surgical teams. The truth is, biopsies are not always definitive; people with cirrhosis have many small nodules in their livers, and while one might be cancerous, others are not. Occasionally, people have to undergo several biopsies over many months before a definite diagnosis can be made.

Source: MedicineNet.com
http://www.medicinenet.com/liver_cancer/article.htm