Biphasic Mesothelioma
Biphasic mesothelioma is a cancer caused by asbestos exposure. Also called mixed mesothelioma, it is a combination of epithelioid and sarcomatoid cells. Prognosis depends on the dominant cell type and treatment. Immunotherapy can extend survival to 18 months. Symptoms include coughing and chest pain.
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What Is Biphasic Mesothelioma?
Biphasic mesothelioma is a specific cell type of mesothelioma cancer. Like all mesothelioma types, biphasic mesothelioma is caused by asbestos exposure. In biphasic mesothelioma, a combination of two different cell types is present in tumors. The cell types are epithelioid and sarcomatoid.
Biphasic mesothelioma primarily occurs in the pleura (lung linings) or peritoneum (abdominal lining). Biphasic mesothelioma tumors may sometimes form in the pericardium (heart lining) or tunica vaginalis (testes).
- Cell types: Two different cell types are present in the tumor: epithelioid and sarcomatoid.
- Diagnosis: This cell type may be prone to misdiagnosis because early tests can easily miss one of the cell types.
- Effective treatment: Recent trial data shows biphasic patients respond well to immunotherapy. The combo of Opdivo+Yervoy can target chemo-resistant sarcomatoid cells in biphasic tumors.
- Life expectancy: Patients commonly live 18 months or more, depending on the treatment approach.
- Occurrence: About 20% of all mesothelioma cancers are biphasic, making it the second most common cell type.
Biphasic mesothelioma is diagnosed when biopsy tests show at least 10% of both epithelioid and sarcomatoid cells. The portion of each cell type in biphasic mesothelioma impacts treatment options. For patients with more epithelioid cells, traditional chemotherapy, immunotherapy or surgery may be recommended. For those with more sarcomatoid cells, immunotherapy is generally preferred.
In the past, a smaller portion of sarcomatoid cells meant better prognosis for biphasic patients. But with immunotherapy, the difference is so narrow that it may not exist at all.
Because biphasic mesothelioma is more complex to treat than other types of mesothelioma, it is important to work with an experienced specialist. A mesothelioma expert can develop a personalized treatment plan to address this specific cell profile and improve the overall outcome.
Biphasic Mesothelioma Symptoms
Like all forms of malignant mesothelioma, symptoms may not present until decades after asbestos exposure.
Biphasic mesothelioma patients experience symptoms related to the location of their cancer. For example, patients with pleural biphasic mesothelioma may have lung-related symptoms.
Biphasic mesothelioma symptoms may include:
- Chest pain
- Pleural effusion
- Pleural plaques
- Pleural thickening
- Shortness of breath (dyspnea)
The biphasic cell type may also occur in peritoneal mesothelioma cases. Patients with peritoneal biphasic mesothelioma may experience abdominal pain, abdominal swelling and weight loss.
Patient factors, such as overall health, age and pre-existing conditions can also affect cancer symptoms.
How Is Biphasic Mesothelioma Diagnosed?
A biphasic mesothelioma diagnosis may start with general exams and tests followed by imaging scans. This can include X-rays or CT scans. If these scans find visible tumors or excess fluid, the doctor may order a biopsy. Biopsy test results can confirm a biphasic mesothelioma diagnosis. They can also rule it out.
Doctors may also perform blood tests to identify specific biomarkers. These tests can help identify cancers and conditions with symptoms similar to mesothelioma. The number of tests performed varies by each patient.
Lastly, a mesothelioma biopsy is required for an accurate diagnosis. The biopsy sample has to contain at least 10% of both epithelial and sarcomatoid cells to be considered biphasic.
Biphasic mesothelioma has a combination of cell types. So, multiple biopsies may be needed for a pathologist to recognize the two types of cells.
Multiple Biopsies May Prevent Biphasic Mesothelioma Misdiagnosis
Biphasic tumors are not uniform, so the different cell types may be unevenly distributed. This means a single biopsy sample may not show the presence of both types of cells. In one study, more than 50% of tumors eventually diagnosed as biphasic were first mistakenly diagnosed as epithelioid. This was due to inadequate biopsy sample size.
One study noted the accuracy* of initial diagnosis depended on the type of biopsy:
- Accuracy: 83%
- Description: An invasive surgical biopsy that allows doctors to directly examine and take a sample of the suspicious tissue
- Accuracy: 74%
- Description: A minimally invasive surgical biopsy that uses a camera to examine and take a sample of the suspicious tissue
- Accuracy: 44%
- Description: A minimally invasive procedure that uses a CT scan and a needle to take a sample of the suspicious tissue
*In this context, accuracy refers to the percentage of initial diagnoses from a given biopsy type that were the correct and final diagnosis for the patient.
Pathologists test biopsy tissue in various ways to confirm a biphasic mesothelioma diagnosis. This testing often includes immunohistochemistry to detect proteins made by sarcomatoid and epithelioid cells. If both types of proteins are found, the patient may have biphasic mesothelioma.
Biphasic Mesothelioma Treatment Options
The National Comprehensive Cancer Network (NCCN) 2026 guidelines recommend immunotherapy as the preferred treatment for biphasic mesothelioma. NCCN specifically advises the following:
- Keytruda® (pembrolizumab) and chemotherapy
- Opdivo® (nivolumab) and Yervoy® (ipilimumab)
These regimens are preferred for biphasic tumors of any stage or ratio of epithelioid to sarcomatoid cells.
Additional options are available for patients unable to receive the preferred approaches. In such cases, doctors may recommend any of the following:
- Chemotherapy: These drugs kill fast-growing cells in mesothelioma tumors. This can help slow the cancer and reduce symptoms.
- Clinical trials: New drugs and combinations may be available to eligible biphasic patients through clinical trials.
- Immunotherapy: This type of drug helps the immune system recognize and kill cancer cells. Doctors may recommend a solo drug instead of a combo to help reduce side effects and improve comfort.
- Radiation: This treatment uses energy to kill cancer cells. It may help shrink tumors, relieving pain from compressed nerves.
- Targeted therapy: These drugs interfere with specific molecules that cancer cells use to grow and spread. They may help slow progression and reduce symptoms.
In general, doctors don’t recommend surgery for biphasic mesothelioma. But many studies of surgery-based treatments have included biphasic patients.
Historically, the results showed surgery shortened life expectancy compared to other options. These findings came before Opdivo and Yervoy doubled survival compared to chemotherapy. Today, doctors seem more open-minded about the potential benefits of surgery and immunotherapy for biphasic patients.
No matter the final treatment plan, determining the right approach for biphasic tumors is a complex process. Experienced mesothelioma doctors are best qualified to weigh patient factors with the most current research. They can explain how your cancer stage, tumor characteristics and personal health point to the most beneficial treatment options.
Prognosis for Biphasic Mesothelioma
Biphasic mesothelioma survival ranges from about 1 – 3 years. However, survival varies depending on the location of the cancer and the chosen course of treatment:
- 1-year survival rate: 52%
- 2-year survival rate: 19%
- 1-year survival rate: 75%
- 2-year survival rate: 75%
Some recent studies involving cutting-edge treatments have reported longer survival times. For example, one study reported biphasic mesothelioma patients surviving nearly 7 years.
A biphasic mesothelioma prognosis varies patient-by-patient. This variance in prognosis depends on many factors. For example, the ratio of epithelioid and sarcomatoid cells can impact prognosis. Another contributing factor is the location of the tumors.
Depending on various factors, patients may have different treatment options and outcomes. Doctors can explain their patients’ prognoses and answer any questions they have.
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Common Questions About Biphasic Mesothelioma
What is the prognosis for biphasic mesothelioma?
Is surgery an effective treatment for biphasic mesothelioma?
In general, surgery is not a preferred treatment for biphasic mesothelioma at this time, but that may change. Past research indicated it didn't improve prognosis alone or with chemo. But the immunotherapy combo of Opdivo+Yervoy doubled survival compared to chemo. This advancement may open the door to combination plans with surgery plus Opdivo+Yervoy.
In fact, early data shows promise for this treatment option. In a small study, two biphasic pleural mesothelioma patients received Opdivo+Yervoy before and after surgery. One lived 18 months, which is similar to patients treated with just Opdivo+Yervoy. The other biphasic patient lived about a year longer.
Why is biphasic mesothelioma prone to misdiagnosis?
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Katy Moncivais, Ph.D., has more than 15 years of experience as a medical communicator. As the Medical Editor at Mesothelioma.com, she ensures our pages and posts present accurate, helpful information.
Medically
Reviewed by
James Stevenson, MD
Thoracic Medical Oncologist
Dr. James Stevenson is a Board-Certified Medical Oncologist. He specializes in treating mesothelioma and lung cancer and practices at the Cleveland Clinic in Cleveland, Ohio.
