Malignant Epithelioid Mesothelioma

What Is Epithelial Mesothelioma?

Epithelial mesothelioma, also known as epithelioid malignant mesothelioma, is the most common of the three types of mesothelioma cancer. Specifically, it is cancer that develops in epithelial cells that line the portion of the airway known as the bronchus. These cells are highly susceptible to asbestos exposure because they come in contact directly with the air you breathe in.

Epithelial mesothelioma accounts for 50% to 70% of mesothelioma cases. Patients with this tumor cell type live about six months longer than patients with other cancer cell types. It has the best prognosis because it is the most responsive to treatment. As a result, patients with epithelioid malignant mesothelioma often undergo more aggressive and effective treatment plans. 

Characteristics of Epithelial Cells

Epithelial mesothelioma cells clump together in groups, making them distinguishable from other types of mesothelioma cells. These cells do not move as easily as other cell types, so they are less likely to spread (metastasize) to other areas of the body, unlike sarcomatoid mesothelioma. This characteristic is one of the reasons epithelial mesothelioma has a better prognosis than other cell types.

Epithelial malignant mesothelioma cells can take on a variety of shapes and sizes, including cuboid (square), columnar (long), or squamous (flat). They are also characterized by the presence of a noticeably visible nucleus, which contains the cells’ DNA.

Symptoms of Epithelial Mesothelioma

Mesothelioma symptoms are the same no matter the cell type. This means a person with epithelial malignant mesothelioma will likely experience the same symptoms as a person with sarcomatoid mesothelioma. The cell type instead mainly affects the types of treatment used.

If you begin to experience any of these symptoms, talk to your doctor. Be as specific as possible so they can order the correct diagnostic tests for you.

Prognosis for Epithelial Mesothelioma

Cancer survival rates and life expectancy is measured from the time of diagnosis until death. According to recent data from the National Mesothelioma Virtual Bank, the median survival of epithelial malignant mesothelioma patients is 18 months. Patients with biphasic cell type, a mixture of both epithelial and sarcomatoid cells, have a median survival of 10 months, while those with only sarcomatoid have a median survival of seven months.

Other factors can contribute to a better epithelial mesothelioma prognosis. For example, one 2020 study from Oncology Reports found that patients with lower levels of the protein connective tissue growth factor (CTGF) have better prognosis and longer survival. In fact, patients with epithelioid cells live an additional 200 days compared to other cell types. 

“Epithelial cell type by far is the best malignant mesothelioma cell type to have. This patient will definitely have more options such as surgery and is more likely to respond to treatment. The survival rate for epithelial patients is overall significantly longer.”

Karen Selby, R.N.

Patient Advocate

Epithelial Mesothelioma Diagnosis

Accurately diagnosing epithelioid mesothelioma requires several steps, including imaging scans, biopsies, and blood tests. When symptoms first appear, such as cough or shortness of breath, they can be vague and prompt primary care doctors to order several tests to rule out other illnesses. This can delay the more thorough testing necessary for an accurate diagnosis.

Mesothelioma patients typically wait three months after first noticing symptoms before they receive a diagnosis. With this, one of the most important things you can do to help ensure a speedy and accurate diagnosis is to share any history of asbestos exposure with your doctor. If they know about your history, they are more likely to consider mesothelioma or another asbestos-related condition.

Challenges of Diagnosing Epithelioid Mesothelioma

When diagnosing epithelial mesothelioma, there are several obstacles that can delay the process. After a visit to your primary doctor, they may refer you to have imaging tests done. Even with a referral, scheduling these appointments can take weeks. Imaging scans can show abnormalities in the lungs, but they cannot definitively diagnose a condition.

The only way to accurately diagnose epithelial malignant mesothelioma is with a tissue biopsy. This requires taking a small sample of lung tissue to look at the cells under a microscope and confirm the cell type. After imaging tests, it may take several more weeks to book a biopsy appointment.

Role of Immunohistochemistry in Epithelioid Mesothelioma Diagnosis

Immunohistochemistry (IHC) is a laboratory test used to detect proteins on the surface of cells for classifying cancer cell types. The American Society of Clinical Oncology (ASCO) recommends using IHC for diagnosing suspected mesothelioma tumors.

The pathologist uses specialized antibodies that bind to certain proteins on the outside of epithelial mesothelioma cells. Some of the antibodies will bind proteins on epithelial cells, while others will not. This allows the pathologist to differentiate between epithelial malignant mesothelioma and another type of cancer called adenocarcinoma.

Epithelial Mesothelioma Cell Subtypes

After a biopsy, the pathologist will create a report for your treating physician. This report includes cell characteristics, their distribution in the tissue, and an overall diagnosis. 

While all epithelial malignant mesothelioma cases involve epithelial cells, there are additional subtypes that can be identified from a pathology report. The subtype informs your doctor how your cancer might progress, and which treatment options may be best.

Epithelial Mesothelioma Treatment Options

Of the three mesothelioma types, epithelial responds best to treatment. Early-stage epithelioid mesothelioma is treated aggressively with a combination of surgery, chemotherapy, and radiation. According to a recent report in The Annals of Thoracic Surgery, combination therapy resulted in significantly better outcomes for patients with epithelial malignant pleural mesothelioma.

Patients diagnosed with the epithelial variant can also be treated with radiation therapy and immunotherapy. Overall, you have a better chance of improving life expectancy when you seek out specialized mesothelioma care and treatments tailored to your diagnosis. The first step in finding the best mesothelioma treatment is to seek the advice of an expert physician. 

Common Questions About Epithelial Mesothelioma

How does a mesothelioma cell type affect my prognosis and treatment?

Patients with the epithelioid cell type have the most mesothelioma treatment options because their cell type responds the best to all forms of treatment. Epithelioid patients also live an average of 200 days longer than patients with other cell types.

How do I find a doctor who treats epithelial mesothelioma?

Most oncologists are not trained to treat epithelioid mesothelioma. Mesothelioma doctors have trained for years to specialize in the treatment of this cancer. Our Patient Advocates can help you find a top doctor who treats epithelial mesothelioma.

How can epithelial cells turn into mesothelioma?

Epithelial cells line the airways and are constantly exposed to substances from the air you breathe in. One of the main causes of mesothelioma is asbestos exposure. When you inhale asbestos fibers, they can become trapped in the lungs and induce inflammation. Long-term inflammation can lead to mutations in epithelial cells, eventually giving rise to cancer.