Mesothelioma is a rare and often difficult-to-diagnose type of cancer caused by exposure to asbestos, a carcinogenic mineral widely used throughout the 20th century. Mesothelioma also has an extremely long latency period, meaning it can take up to 60 years from the initial asbestos exposure for the disease to develop. Because the disease is so rare and takes years to develop, it can take a long time to receive an accurate mesothelioma diagnosis.
Because of its aggressive nature, early detection can greatly improve a mesothelioma prognosis. If you think you may have been exposed to asbestos or are experiencing symptoms associated with mesothelioma, contact your doctor immediately.
How Is Malignant Mesothelioma Diagnosed?
Diagnosing mesothelioma can be a stressful and time-consuming process. Upon showing symptoms, such as chest or belly pain or a painful cough, a patient’s primary care doctor should be contacted immediately.
Generally, patients undergo a number of blood tests, imaging tests, and biopsies, in addition to a thorough physical examination.
A biopsy remains the only conclusive way to diagnose mesothelioma.
The mesothelioma diagnosis process generally begins with a series of imaging tests, starting with the lowest resolution scans and working up if needed.
- X-rays are low-resolution, low-radiation images that allow doctors a two-dimensional glimpse into a patient’s body. They are able to see irregularities that may indicate the presence of mesothelioma. Fluid buildup, pleural thickening, tumors, and irregularities in lung size are usually visible with an x-ray. Abnormal scans may prompt doctors to move on to higher-resolution imaging tests.
- CT scan
- Computed tomography scans, also referred to as CT or CAT scans, are highly regarded as one of the most valuable medical diagnostic tools. CT scans combine rotating x-rays with computers to create multi-angled images of the body. They not only show if abnormalities are present but also give doctors a deeper understanding of the extent and exact location of the abnormality, making them particularly helpful in diagnosing mesothelioma.
- PET scan
- Positron emission tomography scans, or PET scans, use a small dosage of radiotracer, a radioactive chemical, to produce three-dimensional images doctors can use to see how a patient’s organs are working. PET scans are unique in that they show changes in an organ or tissue at a cellular level, where most diseases begin. This technology allows doctors to stage mesothelioma based on how it has spread throughout the patient’s body.
- MRIs (magnetic resonance images) use powerful magnetic fields and a computer rather than radiation to create high-resolution, three-dimensional images of affected areas in a patient’s body. They are used to identify areas that may require a biopsy and are often used for staging mesothelioma.
Following imaging tests, blood tests tend to be next in line when diagnosing mesothelioma. The most common blood tests used in the diagnostic process are listed below.
- Gaining FDA approval in 2007, MesoMark® was the first blood test to be used for mesothelioma diagnoses. MesoMark® works by measuring levels of soluble mesothelin-related proteins released by diseased cells, allowing doctors to assess the severity of mesothelioma present in the body. However, because sarcomatoid mesothelioma does not release these proteins, MesoMark® is unable to assist in the diagnosis of this mesothelioma cell type and should be used in concurrence with other tests to ensure an accurate diagnosis.
- Cancer antigen (CA 125)
- Cancer antigen 125 is a protein biomarker found in large concentrations of cancer cells. The CA 125 test measures how much of the protein is present in a patient’s blood. When factored in with stage and tumor location, a change in CA 125 levels can help determine a patient’s mesothelioma diagnosis as well as anticipate their response to systemic chemotherapy.
- Mesothelioma patients tend to demonstrate high levels of fibulin-3, another biomarker. The fibulin-3 blood test helps doctors distinguish between a mesothelioma diagnosis and other lung diseases. Tracking a patient’s fibulin-3 levels can also be helpful in measuring the efficiency of their treatment.
Because it can mimic other conditions, a biopsy is required to achieve a conclusive mesothelioma diagnosis. A biopsy involves the removal of tissue in order to determine the presence or scope of the disease. In mesothelioma patients, biopsies allow doctors to determine whether the cancer has spread and, if so, to what extent.
The most common biopsies include needle biopsies, camera-assisted biopsies, and surgical biopsies.
Sometimes called a closed biopsy, needle biopsies are the least invasive type of biopsy available for a mesothelioma diagnosis. They are generally outpatient procedures, meaning patients can come the same day. Needle biopsies have the potential to spread the cancer cells if done incorrectly; therefore, it is imperative to visit an experienced specialist when having this procedure done.
- Pleural biopsy
- The most common needle biopsy, pleural biopsies are done on patients experiencing fluid buildup between their lungs and chest (pleural effusion). An anesthetic is first injected to numb the area; then, a needle is inserted to collect a sample of the fluid and pleura tissue to check for the presence and extent of mesothelioma. The procedure usually lasts about 30 minutes to an hour.
- Similar to a pleural biopsy, during paracentesis, a needle is inserted into the patient’s peritoneal cavity to retrieve a sample of the ascitic fluid buildup in the abdomen. This procedure allows doctors to test for the presence of mesothelioma, as well as relieve patient discomfort. Depending on the level of fluid buildup being drained, this procedure usually takes about 30 minutes.
- Also similar to a pleural biopsy, thoracentesis involves the draining of fluid in the pleural cavity. It is done for diagnostic purposes as well as to reduce patient pain and discomfort. The procedure is fast, usually around 15 minutes in total.
- For patients experiencing fluid buildup around the heart sac (pericardial effusion), a pericardiocentesis procedure may be done to drain the fluid and prevent future buildup. Like other needle biopsies, pericardiocentesis can be helpful in the diagnostic process as well as alleviating patient pain. The procedure usually takes between 20 minutes to an hour.
Camera-assisted biopsies allow doctors to take a closer look at a patient’s disease. They are minimally invasive procedures involving a small camera and computer. Generally, camera-assisted biopsies are used after needle biopsies and before surgical biopsy options.
- During this minimally invasive procedure, a surgeon makes a small incision to insert a viewing tube into the chest cavity. The doctor is able to capture a diagnostic sample and relieve the patient of some discomfort by draining excess fluid. The procedure ranges from 45 to 90 minutes.
- Laparoscopy (sometimes called peritoneoscopy)
- Similar to thoracoscopy, laparoscopy involves making a small incision that allows doctors to insert a viewing tube into the abdomen. Doctors are able to examine the affected abdominal organs and take diagnostic samples. This procedure usually lasts around 75 minutes.
- This camera-assisted biopsy procedure allows doctors to examine the lymph nodes and see if the mesothelioma has spread. It generally takes about 60 to 90 minutes.
Surgical biopsies are used when less invasive biopsies are unable to provide definitive results. They are the most invasive type of biopsy and require hospitalization.
- When a tumor is detected in the chest or lungs, a thoracotomy may be performed. This procedure is used to either collect a sample of the tumor for further analysis, or, when possible, is used as a treatment option to eradicate as much of the tumor as possible.
- Similar to a thoracotomy, when a tumor is detected in a patient’s abdomen, a laparotomy may be performed to either collect a sample or when possible, used to remove as much of the tumor as possible.
Patients are encouraged to keep a copy of all test results and scans for their records. It’s also advised to keep a record of your symptoms, medications, and any questions you have for your doctor.