How is Mesothelioma Diagnosed?

The symptoms of mesothelioma are very similar to those of other conditions, including many common ailments related to aging or infections. Some have described the early symptoms as being similar to flu symptoms. Patient descriptions of symptoms may be a bit vague; thus, diagnosing mesothelioma can be a difficult process.  Further, it takes a pathology specialist to differentiate biopsy or tissue mesothelioma cells from other cancers and give an accurate diagnosis.

These complicating factors can be stressful for patients who are waiting diagnosis.  They may feel like the process is taking too long and that they are not getting the attention they deserve. Patients also sense that something is very wrong with their bodies and are not getting answers despite undergoing a number of medical tests. In most cases, it takes 3-6 months before a definitive diagnosis of mesothelioma can be given – from the moment the patient consults his/her doctor about symptoms to the final diagnosis of mesothelioma type.

Steps in Diagnosing Mesothelioma 

The first step in diagnosing mesothelioma usually involves a patient visiting his/her primary doctor due to symptoms such as pains or breathlessness.  Because these are common ailments linked to many conditions, a doctor typically will not suspect mesothelioma right away.  Instead, the doctor will assess the symptoms based on the patient’s medical history.  It is very important that people who have been exposed to asbestos inform their doctors because that can help the doctor zero in on the true medical issue.  The doctor is alerted to the possibility of mesothelioma and that can speed up the diagnostic process.

In addition to reviewing medical history, a primary doctor will give a physical examination which includes listening to the heart and lungs.  The exam can reveal irregularities of the respiratory or cardiovascular system.  A physical exam can also detect other mesothelioma symptoms like tumors underneath the skin.  If the doctor finds or suspects an irregularity, an imaging test is ordered.

Imaging tests can be used for detecting a wide variety of conditions, including asbestos-related diseases like mesothelioma, asbestosis, and pleural plaque. The main types of imaging tests used in mesothelioma diagnosis are x-rays, CT scans, MRIs, and PET scans. If mesothelioma is present, it will appear as unusual lumps or masses in the infected area (most commonly the lung or chest cavity).  Imaging tests alone are not adequate for an accurate diagnosis of mesothelioma.  In order to give a sure diagnosis, a doctor will then order a biopsy.1

There are various types of biopsies used in mesothelioma diagnosis.  They all essentially involve a doctor taking a small amount of tissue or fluid sample from the infected area. The biopsy may be done surgically or by using a biopsy needle that extracts fluids and tissue. Taking the right sized tissue sample from the right area is important if the pathologist is going to be able to accurately diagnosis the disease. Biopsies are directed by image guided cutting and immunohistochemistry to improve detection of malignancy.2

Then, the tissue or fluids are analyzed in a pathology laboratory to confirm that mesothelioma cells are present.  Analysis can also reveal other important information besides simply whether or not mesothelioma is present. The pathologist will identify the type of mesothelioma cells that are present, how much the cancer has spread, and how the cells are behaving.  This information is crucial for determining the best course of treatment for the mesothelioma.

Blood Testing for Mesothelioma

When malignant cancer cells are present in the body, they release certain biomarkers into the blood stream.  These biomarkers can be detected in a blood test and alert doctors to the possibility of cancers like mesothelioma.  The presence of the biomarkers in the blood does not necessarily mean that cancer is present.  However, it can help alert doctors to the possibility of mesothelioma so they perform further testing.  Imaging scans and biopsies are still needed to confirm mesothelioma.

The two blood tests which are primarily used for detecting mesothelioma are: 

  • Mesomark: Mesomark is an FDA-approved blood test which is used for screening patients for tumor markers. The test works by looking for Soluble Mesothelin-Related Peptides (SMRP) in blood.  As mesothelioma cells release SMRP, elevated levels of these peptides can help doctors detect mesothelioma, even in the earliest stages of the cancer.
  • miRview: The miRview test works by measuring microRNA levels in a tumor.  This helps experts distinguish whether the tumor is mesothelioma or another cancer.  The importance of this test is that it is incredibly accurate (95-96%) and can give a diagnosis of mesothelioma very quickly.  As it often takes several months before mesothelioma can be confirmed through biopsies, a miRview test can expedite the process so patients receive treatment faster.

Currently, blood testing is still not a very accurate method of detecting or diagnosing mesothelioma.  However, medical advancements may soon change this.  Once blood testing for mesothelioma has been improved, early detection of the cancer will be much easier – even in cases where symptoms have not yet occurred. Doctors have been researching a number of ways to identify a variety of biomarkers in effusion and lesions to make diagnosis more accurate.3 Early detection of mesothelioma means that patients will have a much better prognosis and open up more treatment options to patients.

References 

1 Symptoms of Mesothelioma (2010) Retrieved from Mesothelioma Applied Research Foundation at: www.curemeso.org/site/c.kkLUJ7MPKtH/b.4023387/k.643A/Mesothelioma_Information.htm#Diagnosis 

2 Adams, R. F., Gray, W., Davies, R. J. O., and Gleeson, V. (December 2001) Percutaneous Image-Guided Cutting Needle Biopsy of the Pleura in the Diagnosis of Malignant Mesothelioma. Chest. v120:6, 1798. 

3 Arnaud Scherpereel, Bogdan Grigoriu, Massimo Conti, Thomas Gey, Marc Grégoire, Marie-Christine Copin, Patrick Devos, Bachar Chahine, Henri Porte, and Philippe Lassalle Soluble Mesothelin–related Peptides in the Diagnosis of Malignant Pleural Mesothelioma,  Am. J. Respir. Crit. Care Med. v173: 1155-1160.