What tests are performed to help diagnose mesothelioma?

As we mentioned previously, the first test that is usually performed after the history and physical exam is an x-ray of the chest. These x-rays can show areas of fluid accumulation, scarring of the lungs, masses in the chest, and other types of abnormal findings, but they are not as sensitive as other test available today.

The results of the chest x-ray will usually prompt the doctor to order a CAT of CT scan (computerized axial tomography scan) of the chest and abdomen. These scans provide a three-dimensional view of the area of the body the physician is interested in. CT scans have a better ability to show how much solid mass is present and how much fluid contributes to the picture. They also give a much better anatomic picture so your doctor can see how any masses relate to the lung, heart, diaphragm (the muscle that helps you breathe), and the blood vessels in the chest or abdomen. CT scans do not tell the doctor what type of tumor it is or whether the disease has invaded other structures, but they do give a very good idea of whether your disease can be classified as early with minimal disease (Stage I), or advanced with a large amount of disease (Stages III and IV). In mesothelioma, a CT scan is not very good for showing whether your lymph nodes (the round structures in certain positions in the chest and abdomen that drain the lung and intestines and act as filters and sites for immune responses) are involved. The reason it does not show this well is that the pleura can be thickened in areas where the lymph nodes are, and this lumpy, bumpy thickening can be confused with lymph nodes or can hide lymph nodes.

The doctor may also request an MRI (magnetic resonance image). An MRI uses radio waves and strong magnets along with a computer to form detailed images of the body. The MRI can occasionally give the doctor information about whether the diaphragm or chest wall have become involved and if the tumor has invaded through it. Not all mesothelioma specialists use MRIs in their workup.

A PET scan (positron emission tomography) is a relatively new type of scan that shows how the body takes up and uses glucose (sugar). Tumors, cancer cells, and areas that are inflamed or infected use glucose at a higher rate than normal tissues do. Since a radioactive tracer is attached to the glucose injected into your body, the areas which use glucose at a higher rate (i.e. tumors) will hold onto the radioactive tracer longer than normal cells. Areas on PET scans that “light up” as bright spots are abnormal. It is important to know, however, that areas on PET scans are not necessarily cancerous; they can also be the result of inflammation. The PET scan can also give the doctor information as to whether the cancer has spread outside the original area to other parts of the body, and it may pick up areas of spread that are completely unexpected. There have not been enough large studies that prove the usefulness of this scan i nmesothelioma, and therefore it has not been approved by most insurance companies as a standard test for mesothelioma, as it has been for lung cancer. However, there are mechanisms that can help pay for PET scans that doctors who do them (nuclear medicine physicians) can help you with. Ask them about these programs.

Your doctor will also order a biopsy when a tumor or fluid is suspected to be cancerous.

This entry was posted on Friday, July 23rd, 2010 at 7:17 pm and is filed under Mesothelioma. You can follow any comments to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.