Mesothelioma Diagnosis
Diagnosing mesothelioma in a patient who is showing symptoms is a multi-step process. It involves discussing the patient’s medical history and past asbestos exposure, along with testing via chest X-rays, CT scans, and biopsies. Since mesothelioma is rare, it is often recommended to obtain a second opinion to ensure a correct diagnosis.
Challenges in Mesothelioma Diagnosis
- The symptoms are nonspecific. “Nonspecific” is a term used in medicine to denote symptoms that can be caused by a wide variety of diseases. The symptoms caused by mesothelioma are nearly identical to those of many other respiratory conditions. Because many of the conditions are far more common than mesothelioma, it may take a while to rule out the more prevalent causes and arrive at the correct diagnosis.
- The latency period is long. The term “latency period” refers to the time period between being exposed to a carcinogen—in this case, asbestos—and developing cancer. For mesothelioma, the latency period is quite long. It can be 20 to 40 years or even longer. By the time they develop mesothelioma, many people have forgotten about their exposure, and may not think to mention it to their doctors.
- The disease is relatively rare. Mesothelioma makes up 0.17% of all cancer diagnoses in the United States, and there are roughly 3,000 cases diagnosed each year. Doctors learn about mesothelioma in medical school, but they are unlikely to encounter the disease during their careers. Many doctors fail to consider mesothelioma a possible diagnosis, particularly early in the diagnostic process.
These factors can contribute to misdiagnosis of mesothelioma and make early detection of this cancer difficult.
- Medically Reviewed By: Patricia Shelton, M.D.
- Legally Reviewed By: Austin Taylor
- Last Modified March 23, 2023
Symptoms of Mesothelioma
Patients with malignant pleural mesothelioma may experience symptoms that may also be caused by pneumonia or other respiratory infections, COPD (emphysema), asthma, and lung cancer, including:
- Cough
- Shortness of breath
- Chest pain
- Trouble swallowing
- Hoarseness of the voice
These general symptoms include:
- Unexplained weight loss
- Night sweats
- Fever
These symptoms include:
- Abdominal pain
- Constipation
- Swelling of the abdomen
- Diarrhea
- Nausea
- Loss of appetite
Testing for Mesothelioma Diagnosis
Usually, the next step will be to order an imaging study. The specific type will be different for different types of mesothelioma, but commonly it’s one of the following.
Many types of biopsies are used for diagnosing mesothelioma.
In some cases, when an endoscopic biopsy isn’t enough, an open surgical biopsy may be needed. This involves making a larger incision to allow the surgeon to see the inside of a body cavity directly rather than through a scope. For pleural mesothelioma patients, the procedure used is called a thoracotomy, while for peritoneal mesothelioma, it’s a laparotomy.
It can be difficult to distinguish different types of cancer from each other. It’s important to be certain of the type in order to treat the patient correctly.
For example, lung cancer is treated differently from mesothelioma. To ensure that the diagnosis is correct, a series of blood tests known as immunochemistry may be used. These tests look for particular proteins in the blood, which are sometimes known as biomarkers.
Different types of cancer are associated with rises in different proteins. For example, patients with mesothelioma often show a rise in the level of soluble mesothelin-related peptides (SMRPs).
Although studies have shown that blood tests are not accurate enough for diagnosing mesothelioma on their own, they can be a useful adjunct to other types of testing in order to be certain of the diagnosis.
Tests for Staging
Doctors may use additional types of imaging studies for staging mesothelioma.