Early Detection, Diagnosis, and Staging of Mesothelioma

A chest x-ray is often the first test done to look for problems in or around the lungs. Findings that might suggest mesothelioma include an abnormal thickening of the pleura (lining of the lung and chest wall), calcium deposits on the pleura, pleural effusion, or changes in the lungs due to asbestos exposure.

A CT scan uses x-rays to make detailed cross-sectional images of your body. CT scans are often used to help look for mesothelioma and to find the exact location of the cancer and tell whether the cancer has spread to other organs.

This can help determine the stage (extent) of the cancer and whether surgery might be a treatment option. CT scans can also be used to learn if treatment is shrinking or slowing the growth of the cancer.

MRI scans show detailed images of the soft tissues in the body by using radio waves and strong magnets. A contrast material called gadolinium is often injected into a vein before the scan to better show details.

MRI scans can sometimes help show the exact location and extent of a tumor since they provide very detailed images of soft tissues. For mesotheliomas, they might be used to see if cancer has spread to the diaphragm (the thin band of muscle below the lungs that helps us breathe).

For a PET scan, a slightly radioactive form of sugar, known as FDG, is injected into the blood and collects mainly in cancer cells. These areas of radioactivity can be seen on a PET scan using a special camera.

The picture from a PET scan can give the doctor a better idea of whether a thickening of the pleura or peritoneum seen on a CT scan is more likely to be cancer or scar tissue.

If you’ve been diagnosed with mesothelioma, your doctor might use this test to see if the cancer has spread to lymph nodes or other parts of the body. A PET scan can also be useful if your doctor thinks the cancer might have spread but doesn’t know where.

PET/CT scan: Some machines can do both a PET and CT scan at the same time. This lets the doctor compare areas of higher radioactivity on the PET scan with the more detailed picture of that area on the CT scan.

This is an ultrasound of the heart. It might be done if your doctor suspects that you have a pericardial effusion, which is fluid buildup around the heart. This test can also show how well your heart is working.

If you have a build-up of fluid in part of the body that might be from mesothelioma, a sample of this fluid can be taken out for testing.

This is done by putting a thin, hollow needle through a numbed area of skin and into the fluid. This might be done in a doctor’s office or in the hospital. Sometimes ultrasound or an echocardiogram is used to guide the needle.

This procedure has different names depending on where the fluid is:

• Thoracentesis removes fluid from the chest.
• Paracentesis removes fluid from the belly.
• Pericardiocentesis removes fluid from the sac around the heart.

The fluid is examined to see if it contains cancer cells. If cancer cells are found, special tests might be done to see if the cancer is a mesothelioma, a lung cancer, or another type of cancer.

Even if no cancer cells are found in the fluid, a person might still have cancer. In many cases, doctors need to get an actual sample of the mesothelium (the pleura, peritoneum, or pericardium) to know if a person has mesothelioma.

Sometimes a needle biopsy might be used to remove small pieces of tumor for testing. The advantage of a needle biopsy is that it doesn’t require a surgical cut or and overnight hospital stay. But because of their downsides, needle biopsies can have, a more invasive biopsy method such as an endoscopic biopsy or surgical biopsy is usually needed.

Needle biopsies are most often done for tumors in the chest. After numbing the skin, a long, thin, hollow needle is passed between the ribs and into the pleura (lining of the lung and chest wall). An imaging test, such as a CT scan, might be used to guide the needle into the tumor so that small samples can be taken out.

A needle biopsy can also be used to get samples of the lymph nodes in the space between the lungs to see if the cancer has spread there. (See Endobronchial ultrasound needle biopsy below.)

Downsides and risks of needle biopsies

The main downside of using a needle biopsy to diagnoses mesothelioma is that it can only sample small pieces of tissue. Sometimes needle biopsy samples might not be enough to diagnose mesothelioma.

Even if mesothelioma can be diagnosed, sometimes the samples might not be big enough to determine the subtype, which is important in planning treatment.

There's also a slight chance that the needle could put a small hole in the lung during the biopsy. This can cause air to build up in the space between the lung and the chest wall, known as a pneumothorax.

A small pneumothorax might not cause any symptoms. It might only be seen on an x-ray done after the biopsy and will often go away on its own. But a larger pneumothorax can make part of a lung collapse and might need to be treated.

This is often done by putting a small, flexible tube (a catheter) through the skin and into the space to suck the air out and re-expand the lung. It's left in place for a short time as the hole heals.

Endoscopic biopsy is commonly used to diagnose mesothelioma. An endoscope is a thin, lighted tube with a camera on the end that’s used to look inside your body. Long, thin tools can be used through the endoscope to take out tissue samples.

Endoscopes have different names depending on the part of the body where they’re used.

Thoracoscopy (thoracoscopic biopsy)

This procedure, also known as a video-assisted thoracoscopic (VATS) biopsy, uses an endoscope called a thoracoscope to look inside the chest. It can be used to look at the pleura and take tissue samples for biopsies.

Thoracoscopy is done in the operating room while you are under general anesthesia (in a deep sleep). The doctor slides the thoracoscope through one or more small cuts made on your chest to look at the space between your lungs and the chest wall.

This lets the doctor see possible areas of cancer and biopsy different areas in the chest for testing. The doctor can also take out lymph nodes and fluid.

Thoracoscopy can also be used as part of a procedure to keep fluid from building up in the chest, called pleurodesis. This is covered in Treating Mesothelioma.

Laparoscopy (laparoscopic biopsy)

For this test, the doctor uses an endoscope called a laparoscope to look inside your belly and biopsy any tumors there. This is done in the operating room while you are under general anesthesia. The laparoscope is put into your abdomen through small cuts on the front of your belly.

Mediastinoscopy

If imaging tests suggest that the cancer might have spread to the lymph nodes between the lungs, the doctor might want to sample some of them to see if they contain cancer.

The area between the lungs is called the mediastinum, and looking at it with an endoscope is called mediastinoscopy. This is done in an operating room while you are under general anesthesia.

A small cut is made in the front of your neck above your breastbone (sternum). Then a thin, hollow, lighted tube called a mediastinoscope is put in to look at the area. Special instruments can be passed through this tube to biopsy the lymph nodes along the windpipe and the space around the major breathing (bronchial) tubes.

Testing the lymph nodes can help show whether a cancer has started to spread, which might affect treatment options. It can also sometimes help tell lung cancers from mesotheliomas.

Endobronchial ultrasound (EBUS) needle biopsy

For this test, a long, thin, flexible, lighted tube with an ultrasound device at its tip, called a bronchoscope, is passed down your throat and into your windpipe. The ultrasound lets the doctor see the nearby lymph nodes outside the windpipe.

A hollow needle can be passed down the bronchoscope and through the airway wall to biopsy lymph nodes.

This procedure might be done with either general anesthesia, or with local anesthesia (numbing medicine) and light sedation, where you are conscious but very relaxed.

Sometimes, endoscopic biopsies aren’t enough to make a diagnosis, so surgery is needed. By making an incision in the chest (thoracotomy) or in the abdomen (laparotomy), the surgeon can remove a larger sample of the tumor for testing or sometimes take out the entire tumor.