How Do Doctors Diagnose Mesothelioma?
Diagnosing mesothelioma is a multi-step process:
- Physical exam. The first step in any diagnosis is a thorough physical exam. Your doctor will ask you questions and go over your symptoms at this time.
- Ruling out other illnesses. Because mesothelioma is rare, it’s far from the most likely cause of symptoms. A doctor will first check for other illnesses, like pneumonia, and rule out common conditions before looking for cancer.
- Imaging Scans. If cancer seems likely, or other illnesses have been ruled out, your doctor will order imaging scans. This helps the diagnostic team see any tissue abnormalities, such as tumors.
- Biopsy. If abnormalities show up on an imaging scan, doctors will biopsy the area. This involves removing a small amount of tissue. A pathologist looks at the tissue under a microscope to identify cancerous cells, their location of origin, and type.
These are the main steps to getting a diagnosis. In some cases, doctors may use blood tests to look for markers indicative of mesothelioma. This is not a perfect test, but it can help doctors distinguish between mesothelioma and other cancers.
When Do I Need to See a Doctor for a Mesothelioma Diagnosis?
- Chest pain
- Shortness of breath
- Painful coughing
- Lumps on the chest
- Unexplained and unintentional weight loss
- Abdominal pain and swelling
Early signs of mesothelioma are usually mild. Doctors and patients often overlook them, especially since they are similar to signs of more common conditions. If you have these symptoms, and especially if they persist and if you know or suspect you have been exposed to asbestos, ask your doctor about mesothelioma.
This initial step is important because your doctor may be able to rule out mesothelioma. Your doctor can also rule out other conditions that are more common and less serious. If your doctor cannot make a conclusive diagnosis or rules out other conditions, your next step is to see an oncologist.
Imaging Tests for Mesothelioma
Medical providers use several imaging studies to help diagnose the cause of your symptoms.
X-rays are often the first test done to evaluate symptoms related to mesothelioma. This can show a pleural effusion (fluid inside your lungs) or obvious abnormalities of the heart or lung structures. It’s also helpful to rule out common health conditions that are not mesothelioma.
CT scans (computed tomography) use radiation to further evaluate the lungs or abdomen in better detail. This can usually give your provider useful information to explain your symptoms and determine a diagnosis plan.
MRIs (magnetic resonance imaging) use magnetic fields and radio waves instead of radiation to provide different images than CT scans. MRI scans can provide additional information, such as invasion of tumors into other structures that cannot be seen on a CT scan.
PET/ CT scans are specialized tests usually only ordered by an oncologist or surgeon. These scans highlight areas of higher metabolic activity, which is seen in most cancer cells. This is usually used to help determine the stage of the cancer or for surgical treatment planning.
You may need more than one imaging test to ensure the presence of tumors and their locations.
What Does Mesothelioma Look Like on an Imaging Scan?
Reading imaging scans is a skill. It’s best to work with mesothelioma specialists who know what to look for in these images. X-rays can show hazy masses but are far from definitive.
On a CT scan, which images a cross-section of the chest cavity, doctors can see areas of thickening of the pleural tissue, indicating tumors. They can also see tumors in the chest wall and on the diaphragm.
MRIs have the greatest ability to show differences in soft tissue. In these images, a doctor can see where cancer invades the chest wall, which is invisible in other images.
If an imaging scan does show abnormal tissue, the next step is a biopsy. This removes tissue and cells that a pathologist examines under a microscope to look for malignancy. There are several methods for performing a biopsy:
- Fine-needle aspiration: This procedure uses a long, thin needle inserted into one of the imaged tumors. It withdraws a small amount of tissue or fluid for examination. This is usually done at a hospital, but you are able to go home the same day.
- Thoracoscopy: This is minimally invasive surgical procedure that involves a camera to look inside your chest cavity. This allows the surgeon to evaluate areas of abnormality and take biopsies that help confirm a diagnosis. This is also called a surgical biopsy.
- ADD Laparoscopy: This also is a minimally invasive surgical procedure but includes entering the abdominal cavity. The surgeon is able to look inside with a camera and obtain biopsies to help gather more tissue for a diagnosis or determine if the cancer has spread to other organs.
- Endoscopy: An endoscope is a nonsurgical procedure that uses a long tube and camera to look inside the digestive tract. During the procedure, biopsies can be taken to help confirm a diagnosis.
Will I Need Surgery for a Biopsy?
You probably won’t need surgery for a biopsy. In rare cases, doctors need more tissue for pathology or cannot reach the potentially cancerous area with a simple biopsy. In these situations, a surgeon may need to do open surgery to complete the diagnosis. They may remove an entire tumor during this procedure.
Blood Tests for Mesothelioma
Right now, a combination of imaging scans and biopsy tests gives specialists the most accurate way to diagnose mesothelioma.
Unfortunately, there is no definitive blood test for mesothelioma. They can be useful as part of a comprehensive diagnosis, but they are not conclusive. Some of the blood tests used currently include:
- The SOMAmer test: This test can detect over 1,000 different proteins in the blood, and is the most accurate blood test to date. Trials proved doctors could use it to diagnose 90% of patients already known to have mesothelioma.
- MESOMARK: MESOMARK is already approved by the U.S. Food and Drug Administration and can detect mesothelin, a protein associated with mesothelioma.
- Human MPF: Blood tests that detect megakaryocyte potentiation factor, or MPF, can show markers for mesothelioma.
The final step in diagnosing mesothelioma is to assign a stage to the cancer. This describes how advanced mesothelioma is in an individual patient. Various factors help determine how advanced the cancer is:
- The size of the original tumor
- The extent of the spread of the tumor to nearby tissues
- The spread of the cancer to lymph nodes
- The spread of cancer to distant tissues or organs
Staging helps specialists plan for your treatment and helps you make more informed choices about treatment. Mesothelioma can be staged as one, two, three, or four, with one being the earliest stage and four the most advanced.
Assigning a Prognosis
Once your team has diagnosed mesothelioma and staged it, they may give you a prognosis. Keep in mind that prognosis at this stage is largely based on averages from other patients. Your doctors can give you a more accurate prognosis once they see how you respond to treatment.
Prognosis at this point depends mostly on the stage of the cancer and your current overall health. It’s important to consider because it gives you an idea of what to expect and helps inform your treatment decisions.
How Long Will the Diagnosis Take?
In terms of the time it takes from asbestos exposure to diagnosis, the period is usually decades. Mesothelioma takes many years to develop to the point that it causes symptoms. You may have worked around asbestos 50 years ago and receive a diagnosis only now.
The process of diagnosing mesothelioma may take a few months, or even longer if your doctor is stumped or makes a misdiagnosis. It takes this long because of all the tests and procedures needed to firmly diagnose this challenging cancer.
Do I Need a Second Opinion?
Diagnosing mesothelioma is imperfect. There is no single test that can provide a definitive answer, and misdiagnosis happens. It is typical for patients to get a misdiagnosis of something more common and less serious, like bronchitis or irritable bowel syndrome. If you are uncomfortable with your diagnosis, treatment options, or prognosis, you should seek a second opinion from another specialist.
Often it is only after symptoms persist and treatments for other conditions don’t work that doctors consider the possibility of cancer. Sometimes this results in a misdiagnosis of another type of cancer, like lung cancer. Early-stage mesothelioma is difficult to diagnose, and it mimics other types of cancers.
If you feel uncomfortable about a diagnosis, you have every right to see another doctor for a second opinion.
Is it Easy to Misdiagnose Mesothelioma?
Yes, unfortunately, mesothelioma is often misdiagnosed. It is a challenging disease to diagnose for several reasons:
- Early symptoms of mesothelioma tend to be mild and similar to those of other, more common illnesses.
- Even when more advanced, the rarity of mesothelioma means that many doctors first consider other diseases that cause the same symptoms.
- Mesothelioma can be difficult to distinguish from other cancers, especially lung cancer.
- Mesothelioma has a long latency period, taking decades to develop after first asbestos exposure. Patients may not know or remember that they encountered asbestos, a major indicator that mesothelioma is a possible diagnosis.
- Most doctors, even oncologists, have little or no experience with mesothelioma and don’t know to look for it.
Nearly half of all mesothelioma patients receive at least one misdiagnosis before getting the correct one. Advocate for yourself with doctors. If you don’t feel comfortable with a diagnosis, push for more tests or see a mesothelioma specialist.
Common Misdiagnoses for Mesothelioma
Certain illnesses have similar symptoms and diagnostic features as mesothelioma. Because they are much more common, they tend to come up as misdiagnoses for mesothelioma.
Typical misdiagnoses for pleural mesothelioma include asthma, COPD, bronchitis, emphysema, pneumonia, adenocarcinoma, and lung cancer. Peritoneal mesothelioma may be misdiagnosed as irritable bowel syndrome, Crohn’s disease, colitis, ovarian cancer, and other types of abdominal cancers.
Pericardial mesothelioma, which affects the tissue around the heart, can be mistaken for heart failure, tuberculosis pericarditis, coronary heart disease, and other types of cancer. Testicular mesothelioma is very rare and may be misdiagnosed as a hernia, epididymitis, or testicular cancer.
What Should I Do After a Mesothelioma Diagnosis?
Getting a diagnosis of mesothelioma can feel devastating and overwhelming. Have loved ones around you to support you and help with difficult decisions. There are a few things you should do after getting your diagnosis:
- Get a second opinion if you feel you need one. See a mesothelioma specialist to confirm a diagnosis made by a general oncologist.
- Ask your specialist or diagnosing oncologist about the stage of your cancer and prognosis so you know what to expect.
- Select a treatment team and discuss your options.
- Rely on family to support you and the guidance of your doctors to make decisions about treatment.
When Does Treatment Start After Diagnosis?
This is up to you and your doctors, but for the best outcome and prognosis, get started immediately. Your doctors will discuss options with you and suggest the preferred course of treatment.
You should spend some time discussing this with close family. Consider your goals for treatment, such as achieving remission, extending your life, or improving your quality of life. Your treatments will vary depending on which of these you prioritize. Don’t spend too much time mulling it over, though. Early treatment provides the best results.
Learning about and understanding your treatment options can help during the process of diagnosis and deciding on what treatments to choose from. Let your oncologist give you resources so that you can make informed decisions. Ask any questions you have before starting on a treatment plan, so you feel comfortable with the next steps. Involve your loved ones, so you have support and help making important decisions.
If you do not have a support system available to you, or would like assistance, please call us at 1-800-692-8608 or fill out our form for your Free Resources. We’re standing by to offer you any assistance you need.
Page Medically Reviewed and Edited byLuis Argote-Greene, M.D.
Luis Argote-Greene is an internationally recognized thoracic surgeon. He has trained and worked with some of the most prominently known thoracic surgeons in the United States and Mexico, including pioneering mesothelioma surgeon Dr. David Sugarbaker. He is professionally affiliated with University Hospitals (UH). His areas of interest and expertise are mesothelioma, mediastinal tumors, thoracic malignancies, lung cancer, lung transplantation, esophageal cancer, experimental surgery, and lung volume reduction. Dr. Argote-Greene has also done pioneering work with video-assisted thoracoscopic surgery (VATS), as well as robotic assisted minimally invasive surgery. He has taught the procedures to other surgeons both nationally and internationally.