How Is Mesothelioma Diagnosed?

Biopsy is the only way to confirm a mesothelioma diagnosis with certainty. The procedure provides a direct and accurate look at the cells that form a mesothelioma tumor.

Doctors take small tissue samples and examine them under a microscope to detect cancer cells and make a diagnosis. Additional tests aid in staging tumors and monitoring treatment response.

Tests Used to Diagnose Mesothelioma
  • Biopsies: A biopsy involves collecting a tissue sample and examining it under a microscope to check for abnormal cells.
  • Blood tests: Blood tests can measure levels of mesothelioma cancer cells and determine the effectiveness of treatment.
  • Imaging tests: PET and CT scans tell doctors where tumors are forming, how large they are and which structures they could affect within the body.
  • Physical exam: Your provider performs a physical exam to identify signs of disease and your overall function. This test could identify the need for further treatment.

The results of other medical tests, such as routine blood work or chest X-rays, may indicate the need for cancer testing that eventually leads to a mesothelioma biopsy and diagnosis. The diagnostic process isn’t linear for everyone, and the order of tests varies significantly.

Key Facts About Diagnosing Mesothelioma
  • Thoracic biopsy has a 98% diagnostic accuracy rate for diagnosing mesothelioma.
  • Thoracoscopy is the most accurate diagnostic test for pleural mesothelioma, and laparoscopy is best for peritoneal mesothelioma.
  • In 2020, the latest year data is available, there were 2,681 new mesothelioma diagnoses in the U.S., according to the CDC.
  • Between 2016 and 2020, 46% of mesothelioma diagnoses happened in the later stages of the disease, underscoring the importance of speaking to your doctor early about a history of asbestos exposure and cancer screenings.

Testing for Mesothelioma

Biopsies, imaging tests, blood tests and physical exams are among the different tests used to diagnose mesothelioma. The first step in diagnosing mesothelioma is typically a physical exam. During a physical exam, your doctor will ask you about your medical history.

Based on your asbestos exposure history, your doctor will look for symptoms of mesothelioma, such as fluid buildup in the chest, known as pleural effusions, or ascites in the abdomen. After this exam, your doctor will determine if you need imaging scans based on symptoms or a biopsy to test for cancerous tissue.

Process of how mesothelioma is diagnosed
Accurately diagnosing mesothelioma takes several steps and involves a variety of tests.

Doctors use imaging tests to identify the location and size of tumors. Mesothelioma blood tests aren’t accurate enough to diagnose the disease but can indicate potential responses to treatment.

One type of biopsy only requires a needle to extract fluid and cancer cells from a tumor. This test, known as cytology or fine-needle biopsy, has become a more accurate and reliable way to diagnose mesothelioma. Correct interpretation and diagnosis with cytology require experienced mesothelioma specialists.

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What Happens During a Mesothelioma Biopsy?

During a mesothelioma biopsy, small fluid or tissue samples are taken from the patient and examined under a microscope to check for cancer cells. These samples help doctors diagnose the type and stage of the cancer and plan the best treatment.

There are several types of biopsy, such as thoracoscopy, laparoscopy and fine-needle biopsy. The biopsy process differs for each type of mesothelioma biopsy, depending on tumor location and depth.

Mesothelioma Biopsy Options
  • Needle Biopsy: Also known as a fine-needle biopsy or fine-needle aspiration, it’s used for tissue samples that are hard to obtain
  • Laparoscopy: A type of endoscopic biopsy best for peritoneal mesothelioma
  • Mediastinoscopy: For biopsies of the lymph nodes and around the windpipe for pleural mesothelioma cases
  • Thoracoscopy: Most accurate for diagnosing malignant pleural mesothelioma
  • Surgical Biopsy: Used when an endoscopic or fine-needle biopsy isn’t possible

Your biopsy may take several hours or require an overnight hospital stay. Doctors always provide anesthesia to reduce pain. You may need to monitor the incision site for signs of infection after the procedure.

Pathologists look at biopsy samples under a microscope to see what types of cancerous cells are present. They use immunohistochemical testing and other pathology techniques to identify mesothelioma cells.

Survivor Story
Survivor Story
Cheryl Pilkington Pleural Mesothelioma Survivor

Physician and Survivor: Biopsy Confirms Mesothelioma Diagnosis

Cheryl’s background as a doctor helped lead to her mesothelioma diagnosis in stage 2, which is more treatable than later stages. She’d had a routine chest X-ray that initially attracted little attention. Experiencing shortness of breath a month later, Cheryl took a closer look at her X-ray and noticed an abnormality, leading to a biopsy that confirmed her diagnosis.

Read Cheryl’s Story

How Doctors Determine Stages of Mesothelioma Cancer

Doctors use the same diagnostic procedures, such as biopsies and imaging tests, to stage mesothelioma cancer. Some patients may receive a biopsy before imaging. Blood tests don’t play a role in staging mesothelioma. 

Results of mesothelioma tests commonly take several days to weeks, depending on how busy the cancer center is. Most patients learn about their stage when they first receive their mesothelioma diagnosis.

Tests Used for Mesothelioma Staging
  • Biopsies: The only way to determine whether you have mesothelioma. Identify whether cells within a mass are cancerous. Tissue and lymph node biopsies can confirm the location and spread of tumors.
  • Imaging Scans: Imaging tests, such as X-rays, computed tomography scans, magnetic resonance imaging and positron emission tomography can reveal the location and size of tumors in tissues, lymph nodes and other organs.

Imaging scans often occur before biopsy procedures to determine where to collect tissue samples. These scans help visualize tumors and track their response to treatment. A combination PET-CT scan with contrast dye is the gold standard for mesothelioma imaging. MRIs can also show whether cancer spreading has occurred.

“I did get used to the routine of going in for scans, but I still experienced ‘scanxiety,’” said peritoneal mesothelioma survivor Tamron Little, who used positive thinking to overcome anxiety. “Think positive thoughts. I know this may seem cliché, but it works. Thinking positively will take your mind off the scan.”

Early Detection and Mesothelioma Stages

Early detection of mesothelioma is critical for improving patient outcomes and increasing treatment options. Asbestos exposure, the primary cause of mesothelioma, often occurs decades before symptoms manifest, making early diagnosis challenging. 

Prompt detection enables healthcare providers to initiate treatment sooner. Rapid treatment improves prognosis and extends survival. Pleural mesothelioma specialist Dr. Jeffrey Velotta told The Mesothelioma Center, “If we could diagnose patients a year earlier, we could start treatment earlier. Then we’d put them in a protective mode where we monitor, rather than manage, advanced tumor growth.”

There are many benefits to early mesothelioma detection, but between 2016 and 2020, 46% of mesothelioma diagnoses occurred in later stages of the disease. It’s essential to start discussions and cancer screening with your healthcare providers as soon as possible if you have known asbestos exposure. 

Early mesothelioma treatment, including surgery, chemotherapy and radiation therapy, offers better therapeutic responses and improved quality of life for patients. Early detection and better access to screening programs can lead to improved patient outcomes.

Why Is Diagnosing Mesothelioma Difficult?

Diagnosing mesothelioma is difficult because symptoms often mimic more common illnesses. Mesothelioma survivor Wendy M. Phillips told us “I went to the hospital with a swollen arm and was initially told I had a blood clot. Further testing revealed mesothelioma tumors were blocking my lymph nodes.”

The Patient Advocates at The Mesothelioma Center add, “Many patients we speak with have told us they were diagnosed after going to the hospital for what they thought was an unrelated symptom.” The decades-long latency period between asbestos exposure and the development of mesothelioma means 20 to 60 years may pass before symptoms arise. 

Getting a second opinion from a mesothelioma specialist is essential because many primary care physicians and oncologists have never encountered mesothelioma. Without knowledge of asbestos exposure, they may misdiagnose mesothelioma or not consider it as a possible diagnosis. 

Most people who contact us about diagnosing mesothelioma are looking for a second opinion. We can connect them with mesothelioma specialists and arrange appointments and treatment if they do receive a confirmed mesothelioma diagnosis.

The Importance of Finding a Mesothelioma Specialist

Mesothelioma specialists have invaluable experience from years of dedicated treatment of mesothelioma patients. In contrast, a general practitioner or oncologist might go their entire career without diagnosing or treating a single case of asbestos-related cancer.


The number of patients The Mesothelioma Center at has connected to mesothelioma specialists.

Second opinions can significantly impact treatment outcomes, potentially prolonging a patient’s life. General healthcare providers might need more specialized experience, which could limit the comprehensiveness of the care they can offer. 

“At first, I was under the care of an oncologist who said he knew nothing about mesothelioma. But I finally found the right mesothelioma specialist,” Tamron Little told us. “I was presented with a roadblock and decided to go around it.”  

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What to Do After a Mesothelioma Diagnosis

Deciding on treatment is the most critical first step after a mesothelioma diagnosis. Treatment for mesothelioma may include surgery, chemotherapy, radiation therapy or immunotherapy.

Your doctor recommends treatments based on where the tumors formed, their cell type and stage of progression. Doctors specializing in mesothelioma have access to innovative therapies and clinical trials

Being diagnosed with mesothelioma can feel overwhelming to patients and their families. One of the best coping strategies is to build a mesothelioma support network. Reach out to family, friends, neighbors and community members. A robust support system will help you get through the challenges of a mesothelioma diagnosis.

Ask your cancer center if there is a social worker who can help you access local family resources. Your cancer center may also have a therapist available for counseling. Mesothelioma support groups can also help, creating opportunities to talk with others who understand your journey.

Common Questions About Diagnosing Mesothelioma

What should you do if you think you have mesothelioma?

If you have a history of asbestos exposure and develop mesothelioma symptoms, make an appointment with your primary care physician. They’ll refer you to a specialist if they believe you need further testing.

How long does it take to get a mesothelioma diagnosis?

The average time from initial symptoms, such as shortness of breath or chest pain, to a mesothelioma diagnosis is approximately 3 months.

How do you prepare for a mesothelioma biopsy?

Stop taking any blood-thinning medication at least 5 days before a biopsy. Wear loose clothing to the appointment, and plan to have a designated driver take you home. Don’t eat or drink anything 6 hours before your appointment. Plan to spend several hours undergoing the biopsy. Some biopsies, such as thoracoscopy, require at least a 1-night stay in the hospital.

Why is it essential to get a second opinion?

Seeking a second opinion from a mesothelioma specialist is essential because they have expertise in diagnosing and treating the disease. A specialist may offer a more accurate diagnosis and recommend better treatment options than a general oncologist.

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