Malignant mesothelioma is rarely detected early. Symptoms of mesothelioma can mimic those of other conditions, and often do not develop until late in the disease. For this reason, a diagnosis is complex and is often only made when the disease is advanced. Unfortunately, the later in the disease process that detection takes place, the lower the chances of survival.
Current Screening Tests for Mesothelioma
To catch the disease as quickly as possible, some doctors recommend screenings for people who have been exposed to asbestos in the past. Both of the most commonly used screenings are painless imaging studies. They include:
- Chest XRay, or CXR: A black-and-white image of the lungs. In mesothelioma, the pleura, or lining, of the lungs, is typically thickened. Often, a build-up of fluid called a pleural effusion is also present which can hide the pleural thickening.
- Computed tomography, or CT scan, of the chest: A series of X-rays taken from different angles and processed by a computer. A CT scan allows the doctor to see a cross-section of your body and gives more detail than a standard X-ray. The doctor can have a better view of any pleural effusions and pleural thickening.
Because mesothelioma most commonly develops in the pleura, visually observing changes in the pleura is one of the main ways that doctors currently look for the disease. Other tests like biopsies can then confirm if the disease is present. Unfortunately, when the disease reaches the stage where it can be seen on X-ray or CT scan, it is often too advanced to cure. For this reason, doctors are trying to develop more tools for early diagnosis of the disease, in the hopes that catching it early will improve survival.
Future Mesothelioma Tests in Development
Researchers are currently investigating several biomarkers, or chemical signals, in the body that may help doctors identify people who are at high risk for developing mesothelioma, so that the disease may someday be stopped before it ever develops. These include:
- Breath biomarkers: Doctors are trying to figure out how chemicals in the breath of people with mesothelioma differ from the breath of people without the disease. When doctors have this information, they plan to develop a breath test for the disease. They hope that by looking for chemicals in breath linked to mesothelioma, they can more easily find the disease in its early stages before it has spread. One study is ongoing and is expected to last until 2022.
and pleural fluid tests:
The levels of several substances are often higher in someone with mesothelioma.
Doctors are studying how testing one or more of these substances may lead to
earlier detection of mesothelioma. These substances include:
- Soluble mesothelin-related peptides, or SMRPs: These substances are chemical fragments normally found in the body. However, they are present at much higher levels in certain cancers like mesothelioma. They can be found in both blood and pleural fluid. The MESOMARK test has been approved by the FDA to monitor SMRP levels in people with mesothelioma.
- Osteopontin: This chemical is a protein that is present at high levels in cancers like mesothelioma. High levels of osteopontin are linked with more advanced mesothelioma.
- Fibulin-3: Fibulins are a type of protein whose link to cancers like mesothelioma was only discovered in recent years. High levels of fibulin-3 have been found in both blood and pleural fluid of people with mesothelioma.
- Megakaryocyte potentiating factor, or MPF: This chemical is a byproduct of mesothelin production. Like SMRPs, mesothelin is normally found in the body, but is present in high quantities in mesothelioma.
- microRNA: These substances are common in plants, animals and humans, and scientists are still learning about their role. However, cancers like mesothelioma produce their own specific microRNAs which can be found in the blood. Specifically, the microRNAs miR-103a-3p, miR-126 and miR-625-3p are linked to mesothelioma.
Mesothelioma is a deadly disease which is often not diagnosed until its advanced stages, when it is difficult to treat. Currently, only chest Xrays and CT scans are routinely used to screen for the disease. However, with new research into chemical markers in blood, breath and fluid, doctors are hopeful that new screening tools can be developed to catch the disease earlier. In turn, doctors hope that mesothelioma diagnoses can be made earlier in the disease and may lead to improved survival.