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Biphasic mesothelioma is the second most common mesothelioma cell type. It accounts for approximately 20 to 35 percent of all mesothelioma diagnoses. The ratio of epithelioid to sarcomatoid cells determines a patient’s prognosis.

What is Biphasic Mesothelioma? 

A biphasic, or mixed, mesothelioma tumor is made of both epithelioid cells and sarcomatoid cells. These tumors can form in the pleura, peritoneum, pericardium, or testes. However, biphasic tumors are more common in malignant pleural mesothelioma (i.e. in the lung) than in peritoneal or other forms of mesothelioma. To be classified as biphasic, a tumor must contain at least 10% of both epithelioid and sarcomatoid cell subtypes. If it contains more epithelioid than sarcomatoid cells, a patient likely has more treatment options and a better prognosis because epithelioid cells are generally more responsive to various treatments. Based on a landmark study called Checkmate 743, patients with biphasic mesothelioma are increasingly recommended immunotherapy instead of chemotherapy, because it has a similar success rate as with tumors that only have epithelioid cells.

Things to Know About Biphasic Mesothelioma

Prognosis varies: Two people diagnosed with a biphasic cell type may have drastically different prognoses. This is because biphasic tumors with a majority of epithelioid cells are more treatable.

Second opinions can be important: A proper diagnosis is important to secure the best treatment possible for biphasic mesothelioma. Sometimes even doctors make mistakes, so consider getting a second opinion if your treatment options are limited. 

Biphasic Mesothelioma Characteristics

There are several key characteristics of this cell type:

  • How well a biphasic tumor responds to treatment depends on which type of cell, epithelioid or sarcomatoid, is more prevalent.
  • Biphasic tumors with more epithelioid cells grow faster than biphasic tumors with more sarcomatoid cells. They do not, however, spread to other parts of the body as quickly.
  • Epithelioid and sarcomatoid cells tend to grow in separate parts of the same biphasic tumor. This makes diagnosing biphasic mesothelioma difficult.

Common Biphasic Mesothelioma Symptoms

Biphasic mesothelioma symptoms, such as these, can take 10-50 years or more to develop, given a decades-long latency period between asbestos exposures and cancer development:

  • Abdominal pain or bloating
  • Chest pain or pressure
  • Coughing up blood
  • Difficulty breathing or swallowing
  • Dry cough
  • Pleural effusion (buildup of fluid in the pleura, which may or may not be drained)
  • Shortness of breath
  • Weight loss

Age, sex, overall health, and stage of mesothelioma can also impact symptoms and their severity. And because early symptoms can be nonspecific, mesothelioma may be misdiagnosed as different carcinomas or sarcomas or even something as simple as pneumonia. 

Symptoms of biphasic mesothelioma are often aligned with the location of tumors. For example, in the case of malignant biphasic peritoneal mesothelioma, patients may experience abdominal pain and swelling because of tumors in their abdomen. These symptoms can be mistaken for IBS or Crohn’s disease. Patients with malignant biphasic pleural mesothelioma may have chest pain because of tumors in the pleura (lining of their lungs). The symptoms may be similar to COPD.

Biphasic Mesothelioma Diagnosis

Your pathologist will conduct several tests to diagnose your condition, including imaging tests, biopsies, cytology, and immunohistochemical approaches. 

Imaging Tests

The first step specialists take to diagnose biphasic mesothelioma is an imaging test, such as an x-ray, CT scan, or MRI. Imaging tests are mainly used to locate cancerous growths in the chest and abdominal cavities. Determining the specific cell type of a tumor is not possible from imaging tests alone.


Epithelioid and sarcomatoid cells tend to grow in separate parts of the same biphasic tumor, making visual diagnosis a nearly impossible task. Both cell types also look very similar to the cells of other cancers.

To perform a biopsy, a surgeon takes a tissue sample directly from the tumor mass they located with an imaging scan. Common biopsies used to confirm a biphasic mesothelioma diagnosis include fine needle aspiration or a standard surgical biopsy, such as a thoracotomy or laparotomy.


Sometimes, a diagnosis may be made from cytology (a fluid sample), rather than from a tissue sample (biopsy). Recurrent fluid accumulation is a common early symptom of mesothelioma, regardless of the site. If mesothelioma is affecting the lung, for example, a person may have pleural effusions, which means a buildup of fluid within the lining of the lungs. The fluid is removed through a needle process called thoracentesis. If mesothelioma is affecting the abdomen, there may be a buildup of fluid that is removed through a needle process called paracentesis. A doctor may review the fluid for indications of mesothelioma, but the absence of cancer cells does not mean there is no mesothelioma. If fluid continues to accumulate without explanation, the likely next step is a biopsy.


Specialists then use a diagnostic technique called immunohistochemistry to obtain an accurate biphasic diagnosis. Pathologists, doctors who specialize in identifying cells, stain samples obtained from a biopsy with a dye that helps distinguish cancer cells.

Ensuring an accurate diagnosis

Biphasic tumors tend to be more difficult to diagnose accurately because tumors are not uniform given their mix of sarcomatoid and epithelioid cells. Biopsy samples are small and may not capture both types of cells or enough tissue to be diagnositc. Multiple biopsies can prevent misdiagnosis and ensure accurate histological subtypes. The type of biopsy also plays a factor, with some biopsies being more accurate than others:

  • Thoracotomy. This procedure is highly accurate but highly invasive because it is a form of open surgery under general anesthesia., It is most often done during another surgical procedure, such as talc pleurodesis
  • Thoracoscopy. Much less invasive, this procedure is still very accurate but not quite as sensitive as a thoracotomy for diagnosis. Instead of a large incision, one or more small incisions may be made so that a doctor can insert a camera for guidance in obtaining a tissue sample. It is often referred to as VATS, or video-assisted thoracoscopic surgery.
  • CT-guided biopsy. This less-invasive procedure may not accurately diagnose biphasic mesothelioma. It is often referred to as a needle biopsy and does not require general anesthesia. 

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Biphasic Mesothelioma Treatment Options

The availability of treatment options for a biphasic patient depends on the location of the tumor and the stage of cancer.

Early-stage patients may be eligible for an aggressive combination of curative surgeries.

Advanced-stage patients may only be eligible for palliative treatments designed to ease symptoms. A qualified mesothelioma specialist can determine which course of treatment can provide the most improved prognosis.

Mesothelioma treatment plans often include a combination of two or more treatment options, including surgery, chemotherapy, and sometimes radiation therapy. This combination of therapy is called multimodal therapy. Overall, using more than one treatment has improved the life expectancy of patients with mesothelioma in any area of the body. Your oncologist will work with you to determine the best treatment plan to improve your prognosis. 

For patients with biphasic tumors, some treatment options like chemotherapy and radiation can be ineffective against the sarcomatoid cells in their tumors. However, if found when the tumor is localized in an early stage, surgery plus chemotherapy or radiation can offer a better prognosis. 

The ratio of epithelioid and sarcomatoid cells may play a role in the aggressiveness of a treatment plan. A tumor containing mostly epithelioid cells will be more receptive to aggressive treatments than a tumor containing more sarcomatoid cells.

Emerging Treatments for Mesothelioma

Clinical trials give mesothelioma patients access to emerging treatments. Some therapies are still in clinical trials while others have received FDA approval. The effectiveness of these treatments varies based on the histology of the tumor. Researchers are studying gene therapy, cryotherapy, and immunotherapy to treat mesothelioma. 

A landmark clinical study called Checkmate 743 compared immunotherapy with chemotherapy in treating pleural mesothelioma.  With immunotherapy, patients with biphasic pleural mesothelioma could achieve a three year survival rate similar to that of patients who had tumors that only contain epithelioid cells. Immunotherapy is used to stimulate the immune system to fight cancer on its own. In particular, the combination of two immunotherapy drugs, Opdivo® (nivolumab) and Yervoy® (ipilimumab) have been shown to improve survival rates by 50%. These two drugs are an FDA-approved treatment for malignant pleural mesothelioma, and work together to identify and target cancer cells in the body. These treatments are now standard options for advanced stages of mesothelioma, as well as for mesothelioma that involves sarcomatoid cells, such as the biphasic type.

Biphasic Mesothelioma Prognosis, Survival Rate, and Life Expectancy

The prognosis for patients diagnosed with biphasic mesothelioma is generally less favorable than those diagnosed with epithelioid mesothelioma, but more favorable than those with sarcomatoid mesothelioma.

Biphasic mesothelioma patients have a median survival rate of 12 months, compared with 12 to 24 months for epithelioid type and 6 months for sarcomatoid type.

Prognosis depends on the type of mesothelioma, stage, age, gender, and a patient’s overall health. Life expectancy increases if cancer is found in earlier stages. Additionally, younger patients, female patients, and patients in good overall health tend to have a longer life expectancy.  

Treatment also plays an important role in increasing life expectancy. Patients should speak with their doctors about treatment options, including clinical trials and emerging therapies, that can help extend life. Immunotherapy can improve biphasic survival rates to those more similar to epithelioid-only mesothelioma.

Biphasic Mesothelioma FAQs

Is biphasic a specific type of mesothelioma?

Biphasic mesothelioma describes a type of mesothelioma where tumors are made up of both epithelioid and sarcomatoid cells. This type of mesothelioma is different from epithelioid or sarcomatoid mesothelioma, which are each made up of only one cell type. 

[h3] What is the life expectancy of a person with biphasic mesothelioma? 

Patients with biphasic mesothelioma have a median life expectancy of 12 months, compared with 12 to 24 months for epithelioid mesothelioma and 6 months for sarcomatoid mesothelioma. 

[h3] How does cell type affect treatment and prognosis?

Epithelioid cells are generally more responsive to treatment than sarcomatoid cells. As a result, patients with biphasic mesothelioma tumors with a higher percentage of epithelioid cells generally respond better to treatment and have a better prognosis than patients with more sarcomatoid cells. 

[h3] How do I get help with a biphasic mesothelioma diagnosis?

To learn more about mesothelioma, find a mesothelioma specialist, or find information on cancer treatment, contact Mesothelioma Group at (800) 333-8975.