Mesothelioma Diagnosis

Mesothelioma is a rare cancer mostly caused by asbestos. It strikes the tissue layer over many of the body’s internal organs. That tissue is the mesothelium.

About 3,000 new cases are diagnosed in the US every year. Because mesothelioma is so rare, and since it is symptomatic in a way that all the other diseases are, it is not easy to diagnose. There are several tests and procedures to get a clear mesothelioma diagnosis.

Difficulties in Diagnosing Mesothelioma

Mesothelioma symptoms can include chest pain, tiredness, and palpitations. And there might be dozens of other diseases that might give us the same symptoms. That’s why mesothelioma is so often misdiagnosed.

Then there is the interval of time between asbestos exposure and mesothelioma symptoms, which can range from 20 to 71 years. Because the disease is so late, the patient doesn’t even remember having been exposed to asbestos in the first place.

Mesothelioma is so rare that doctors will not even think of this diagnosis if they aren’t aware that the patient was exposed to asbestos.

Diagnostic Tests For Mesothelioma

Multiple tests are performed to confirm a mesothelioma diagnosis. Those include scans, biopsy, and blood work. They’ll do tests to confirm the original mesothelioma diagnosis, and to measure the extent of the cancer’s invasion in the body.

Imaging Tests for Mesothelioma

Images from imaging procedures make precise maps of internal organs. Examples of imaging procedures include X-rays, computed tomography (CT) scans, and ultrasounds. The type of image that’s obtained depends on the patient’s symptoms and the body part under examination.

They are used early in the stage of mesothelioma diagnosis to confirm a cancer diagnosis. This is diagnostic imaging. Even the status of the cancer is checked through imaging.

Other types of tests will be needed to determine the type of cancer.

Types of Mesothelioma

There are three main types of mesothelioma. They are characterized by where they are found within the body.

• Pleural mesothelioma affects the lining of the chest. This lining is known as the pleura. Pleural mesothelioma is the most common type of the disease, making up 75 to 80% of all mesothelioma cases.
• Peritoneal mesothelioma affects the lining of the abdomen. This lining is known as the peritoneum. Peritoneal mesothelioma is less common, making up 10 to 15% of all mesothelioma cases.
• Pericardial mesothelioma affects the lining of the heart. This lining is known as the pericardium. Pericardial mesothelioma is very rare, making up less than 1% of all mesothelioma cases.

Diagnostic Imaging for Pleural Mesothelioma

A common first step in getting a pleural mesothelioma diagnosis is a chest X-ray. This can rule out other common problems, such as pneumonia, and the tumor may also be visible on the X-ray image. 

Seeing a mass on an X-ray strongly suggests a tumor, but it doesn’t reveal anything about what kind of cancer it is. In many cases, the tumor is small and may appear only as an area where the pleura is unusually thick. There may also be fluid buildup around the lung.

A CT scan of the chest may also be used. This is a more detailed scan that allows doctors to get a more complete and three-dimensional view of the chest’s structures. Sometimes a CT scan is done instead of a chest X-ray. In other cases, it’s the next step after a chest X-ray.

Diagnostic Imaging for Peritoneal Mesothelioma

A CT scan of the abdomen is commonly performed for those having digestive symptoms. This is a detailed scan that is made using a series of X-ray images. A computer then uses these to generate a 3D image that your doctor can view. 

For a peritoneal mesothelioma patient, a CT scan may show one or more masses in the abdomen or one or more areas where the peritoneum has thickened. Malignant peritoneal mesothelioma often spreads within the abdomen before diagnosis, so there may be multiple tumors present.

Diagnostic Imaging for Pericardial Mesothelioma

The diagnostic process for pericardial mesothelioma often includes an echocardiogram. This type of imaging is an ultrasound test. Ultrasound tests use sound waves to make an image of the heart. 

The most common finding in pericardial mesothelioma patients is fluid buildup around the heart. The test may also show pericardial thickening or a mass next to the heart.

A chest X-ray may also be part of the diagnostic process for pericardial mesothelioma. Similar to pleural mesothelioma, one purpose is to rule out common medical problems that can also cause symptoms like chest pain.

Getting a definitive diagnosis of mesothelioma requires a biopsy. This procedure involves taking a small sample of tissue or fluid from the patient. Once a sample is collected, it can be examined for the presence of disease.

Biopsy for Pleural Mesothelioma

If the pleural mesothelioma tumor is close to the chest wall, a needle biopsy may be performed. This procedure obtains the tissue sample with a needle that is inserted through the skin. Ultrasound is used to guide the needle to the right place. However, depending on the location of the tumor, a needle biopsy may not be possible.

Another way to perform a biopsy is through a thoracoscopy. In this procedure, a small incision is made in the chest wall. A flexible tube-like device with a camera on the end is then inserted into the body. Specially designed surgical instruments can be passed through the tube. 

Thoracoscopies let the surgeon obtain the biopsy sample and visualize the structures of the chest to look for tumors. Some patients have a buildup of fluid around the lung, which can be drained during the procedure.

Biopsy for Peritoneal Mesothelioma

The most common way to get a biopsy for peritoneal mesothelioma is through a laparoscopy. In this procedure, a small incision is made in the skin of the abdomen, and a flexible tube-like device with a camera on the end is inserted into the body. This allows a surgeon to get a sample for the biopsy, and also to visualize the organs of the abdomen to look for tumors.

For tumors of the abdomen, a needle biopsy is occasionally used if the tumor is close to the skin.

Biopsy for Pericardial Mesothelioma

Getting a biopsy for pericardial mesothelioma can be challenging. Because this type of cancer originates in the lining around the heart, the tumor is usually somewhat difficult to access. The biopsy is almost always done using thoracoscopy. 

If a patient has a buildup of fluid around the heart, it can be drained during the procedure. 

Blood Testing

To ensure a correct mesothelioma diagnosis, a blood test using a science called immunochemistry can be useful. 

Looking for specific immune system markers in the blood helps doctors confirm what type of cancer cells are present. In immunochemistry, a blood sample is taken and tested for one or more specific proteins in the blood.

Although mesothelioma can’t be diagnosed based on a blood test alone, the results of this test can be useful in combination with imaging tests and biopsies. Blood tests also help accurately determine cancer’s cell type.

Subtypes of Mesothelioma

Doctors use the results of the biopsy and blood test to determine the type of mesothelioma cells present in the body. There are three subtypes of mesothelioma.

• Epithelioid mesothelioma is the most common cellular subtype. It makes up 50 to 70% of all mesothelioma cases. It is the least aggressive cell type and typically responds the best to treatment.
• Sarcomatoid mesothelioma is a rare cellular subtype. It is very aggressive and responds poorly to treatment.
• Biphasic mesothelioma is a combination of both epithelioid and sarcomatoid cells. Prognosis and treatment options vary depending on the cell type ratio.

Stages of Mesothelioma

Once a diagnosis is reached, the next step is staging. The stage of mesothelioma cancer refers to how far the cancer has spread within the body. Malignant pleural mesothelioma is the only form of the disease with a formal system of staging.

• Stage 1 cancers remain localized to the area where they originated.
• Stage 2 cancers have spread to nearby lymph nodes.
• Stage 3 cancers have spread to more distant lymph nodes and/or to nearby structures, like the chest wall.
• Stage 4 cancers have spread to other organs of the body.

Doctors may use various tests to determine the stage of a patient’s mesothelioma.

A PET scan helps to determine whether the cancer has spread to other parts of the body. This scan uses a radioactive tracer to check for areas of increased metabolic activity. Increased metabolic activity is a strong indication of the presence of cancer cells. PET scans are often combined with other body scans, like MRI or CT scans.

How to Prepare for Mesothelioma Diagnosis Appointments

The process of getting a mesothelioma diagnosis can take a considerable amount of time because of the amount of tests that are needed. In one 2017 study, the average time between diagnosis and the initial onset of mesothelioma symptoms was approximately 4 to 6 months.

When you discuss your symptoms with your doctor, make sure that you discuss your occupational history, especially if your job may have exposed you to asbestos. This will help your doctor make an accurate diagnosis. The occupational history of anyone that you lived with may also be important because asbestos fibers can stick to clothing or hair.

There are different recommendations for preparing for each diagnostic test. You should be given instructions before each appointment.

How to Prepare for Mesothelioma Imaging Tests

Each imaging test requires different preparations.

• You can usually take your normal medications on the day of your test, but you should always ask your doctor to make sure.
• Although you don’t usually need to fast for an extended period, it’s best not to eat a large meal right before your test. If you’re having imaging tests of the abdomen, then you may need to stop eating completely for a few hours before the test.
• If you tend to feel nervous in enclosed spaces, you may want to practice some relaxation techniques to help you feel more comfortable during the scan. In some cases, doctors can prescribe one pill of anti-anxiety medication.

How to Prepare for a Mesothelioma Biopsy

Because a biopsy is a surgical procedure, it requires more preparation than an imaging test.

• Don’t take any blood thinners in the five days before the procedure. This includes certain over-the-counter medications, like ibuprofen or aspirin.
• Stop eating or drinking at least 6-8 hours before the procedure. Your stomach needs to be empty.
• If you are sedated during anesthesia, you will need someone to drive you home after the procedure.

What Happens After a Mesothelioma Diagnosis?

After a diagnosis of mesothelioma, the next step is to create a treatment plan. In most cases, your treatment will be overseen by an oncologist. An oncologist is a doctor who specializes in the treatment of cancer. The treatment of mesothelioma usually involves some combination of surgery, radiation therapy, immunotherapy, and chemotherapy.

The specific treatments will vary, depending on the characteristics of the cancer. For example, while surgery would be considered for epithelioid mesothelioma in an early stage, it would not be recommended for sarcomatoid mesothelioma. Your mesothelioma specialist will talk with you about their treatment recommendations in your specific case.

FAQs on Mesothelioma Diagnosis

Understanding mesothelioma and its diagnosis can be challenging. Here are some frequently asked questions to help you navigate this complex process.