Mesothelioma Diagnosis

The symptoms of pleural mesothelioma are similar to many other diseases. In most cases, a patient will experience shortness of breath, coughing, and chest pains, which can easily be mistaken for more common disorders. In fact, many people put off seeing a doctor about their mesothelioma symptoms because they mistakenly believe its signs of a minor illness.

Approximately 25 percent of people that have mesothelioma symptoms experience them for six months or more before they are even diagnosed. This is unfortunate because mesothelioma generally reaches the advanced stages of development before any symptoms appear. Anyone who has been exposed to asbestos should be evaluated by a physician specializing in asbestos-related illnesses on a regular basis.

Visiting a Mesothelioma Doctor

When someone visits their doctor with mesothelioma symptoms, the doctor will ask several questions regarding their past and present medical history. It’s important to mention any possible exposure to hazardous substances such as asbestos and other toxins. Mesothelioma can initially be misdiagnosed because physicians want to rule out more common disorders before looking at less likely possibilities.

A doctor visit will include a physical exam to look for signs of mesothelioma or other disorders. Pleural effusion, which is fluid in the chest cavity, can often be a sign of pleural mesothelioma and can be detected during a physical exam. Ascites, which is fluid in the abdominal cavity, can also be detected during a physical exam and may indicate a sign of peritoneal mesothelioma. Pericardial effusion, which is fluid around the heart, can be a sign of pericardial mesothelioma.

As part of a diagnostic work-up, the doctor may order blood tests. These are performed to determine a patient’s general state of health rather than to detect mesothelioma. An elevated level of a protein in the blood called osteopontin will rouse suspicion of mesothelioma. However, a blood test cannot officially determine whether or not a patient has mesothelioma. More extensive tests are needed to determine an exact diagnosis.

Mesothelioma Imaging & Tests

Several imaging tests, including x-rays, computerized tomography (CT) scans, and magnetic resonance imaging (MRI) scans can be used to diagnose cancer. Most doctors will perform more than one kind of imaging test. Chest x-rays are useful to show the abnormalities that occur after exposure to asbestos. The pleura (lining of the chest cavity) may be thickened or it may contain calcium deposits. Pleural effusion can also be seen by x-ray.

Computerized tomography (CT) scans are frequently used for the initial diagnose of malignant mesothelioma. CT scans can also help determine the exact stage of mesothelioma. During a CT scan, a patient will lie on a table surrounded by a ring that contains the scanner. After the scanner takes multiple x-rays of the body, the computer combines the pictures into an image that displays the part of the body being examined.

Doctors will typically order a second set of pictures using a contrast dye to create a better picture. The patient will then be given a radiocontrast agent (a dye) though an intravenous line (IV). An allergic reaction to the contrast solution can include hives or more serious reactions such as breathing difficulties and low blood pressure. Allergic reactions are relatively rare and a patient will be questioned about possible allergies before the test.

Another imaging technique that is sometimes used is called a positron emission tomography (PET) scan. Radioactive glucose (sugar) will be injected in a vein during the PET scan and any cancerous tumors will take up the radioactive material and show up more clearly on the scan. The PET scan can help distinguish between scar tissue and cancerous areas.

Magnetic resonance imaging (MRI) scans are also commonly used to detect cancer. These scans use strong magnets and radio waves to produce images. The body absorbs the energy from the radio waves and then releases it into a pattern. This pattern is then translated by a computer into a highly detailed image of the internal organs. An MRI may be used if the doctor wants to look at the diaphragm for signs of mesothelioma.

Occasionally, a contrast material may be injected during an MRI. MRI scans are not painful, but some people find them uncomfortable since the majority of the body is placed inside a large tube that contains the scanning equipment. There are some MRI machines that are not enclosed, but these are not readily available in all locations. MRI machines also make a loud noise, but many places give patients earphones to block out the noise.

Mesothelioma Biopsies & Tissue Samples

If someone has abnormal fluid in the chest cavity, abdominal cavity, or in the area around the heart, a fluid sample can help determine if they have mesothelioma. The doctor will take a fluid sample by inserting a needle into the chest cavity or abdominal cavity. The sample will later be examined under a microscope to see if it contains cancerous cells. If the sample contains cancerous cells, more tests will be done to determine whether the cancer is mesothelioma, lung cancer, or another form of cancer.

If suspicious spots are shown on an imaging test, the next step will be a biopsy to take a tissue sample. Tissue samples can be collected in different ways depending on the location of the tissue and the size of mass. A thoracoscopy allows the doctor to obtain a tissue sample of a tumor located in the chest. This is useful for pleural or pericardial mesotheliomas. A small incision is made in the chest and a thorascope (a tube-like instrument with a video camera), is inserted to look at any suspicious spots. A similar procedure, called a laparoscopy, is used to obtain tissue samples from the abdomen.

Another procedure used to diagnose pleural mesothelioma is the bronchoscopy. For this test, a flexible tube is inserted into the mouth, through the trachea, and into the bronchi to look for masses in the airway. A sample will then be taken of abnormal tissue.

If the doctor suspects a patient has cancer that has spread to other locations, he or she may perform a procedure called a mediastinoscopy. For this test, an incision is made under the sternum (chest bone) and a thin tube is inserted to examine the lymph nodes. The lymph nodes are small clusters of specialized cells that help the body fight infection. It is common for lung cancer to invade the lymph nodes, but it is less common for pleural mesothelioma. This form of test can especially be useful in distinguishing lung cancer from pleural mesothelioma.

If the imaging tests show large abnormal masses, the doctor may recommend actual surgery. During a thoracotomy, the surgeon will open the chest and remove either large samples of suspicious masses or the entire tumor. If the problem is in the abdomen, the surgeon will open the abdomen during a laparotomy and remove part or all of the tumor(s).

Distinguishing Mesothelioma from Other Cancers

Once tissue and or fluid samples are obtained, a pathologist will examine them under a microscope. Because mesothelioma cells can look like other types of cancer cells, a more powerful electron microscope is sometimes used to help distinguish the cancer cells. Special laboratory tests of the cells are often needed to make a diagnosis of mesothelioma. The immunohistochemistry test examines proteins on the surfaces of cells and can determine if a cancer is mesothelioma or lung cancer. The DNA Microarray analysis test looks at the genes of cancer cells.

After the Diagnosis

If the doctor determines a patient has mesothelioma, the next step is to determine what stage the disease has progressed to. Determining the stage of the mesothelioma cancer will help doctors recommend the various treatment options available. Staging is done by examining the already obtained imaging studies.

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