What Is Sarcomatoid Mesothelioma?

Sarcomatoid malignant mesothelioma is a rare type of asbestos-related cancer. This cancer can affect the lining of the lungs, heart, abdomen or testes. “Sarcomatoid” refers to the tumor cell type. These cells make up most of the tumors for this type of mesothelioma.

Sarcomatoid mesothelioma is a rare subtype in contrast to epithelial. Sarcomatoid tends to be a little more locally progressive.

Sarcomatoid cells grow in connective tissues, such as bones, nerves and tendons. The sarcomatoid type is the rarest of the 3 primary cell types of mesothelioma. For comparison, about 60% of patients have the epithelial type, and 20% have the biphasic type. 

Tumors of the sarcomatoid cell type are more likely to spread to new areas. They’re also more resistant to treatment. These characteristics contribute to the poor prognosis associated with this type of mesothelioma. Thankfully, advances in immunotherapy have helped some sarcomatoid patients far surpass their prognosis.

Key Facts About Sarcomatoid Mesothelioma
  • Sarcomatoid mesothelioma, also known as spindle cell mesothelioma, accounts for 10% to 20% of all mesothelioma diagnoses.
  • Because the fibrous nature of sarcomatoid cells make them resistant to treatment, the prognosis is typically poor.
  • Advances in immunotherapy have demonstrated double survival rates for some sarcomatoid malignant mesothelioma patients.

What Causes Sarcomatoid Mesothelioma?

Asbestos is the primary cause of sarcomatoid malignant mesothelioma. Breathing or swallowing asbestos fibers lead to their accumulation in the body. Over time, irritation and inflammation cause mesothelial cells to turn cancerous. 

Diagram of how inhaling asbestos fibers can cause sarcomatoid mesothelioma.
Diagram shows how inhaled asbestos fibers lead to tumor development.

Mesothelioma risk factors include asbestos exposure on the job, in the military and from the environment. Workers have been exposed primarily at industrial job sites, and veterans were exposed in shipyards and military bases. Secondary exposure also occurred when workers unknowingly brought asbestos fibers home. 

Sarcomatoid Mesothelioma Symptoms

The most common symptoms of sarcomatoid mesothelioma are shortness of breath, chest pain and coughing. Severe symptoms include difficulty breathing and persistent cough. Symptoms may take 20 to 60 years to develop.

Most symptoms depend on tumor location. Sarcomatoid cells are most often found in pleural disease that develops in the lining of the lungs. However, patients with sarcomatoid peritoneal cancer will have abdominal symptoms instead. They may experience bowel problems, abdominal pain and swelling.

Symptoms of Sarcomatoid Mesothelioma
  • Anemia (low iron)
  • Chest pain or abdominal fullness
  • Coughing up blood
  • Fatigue and extreme tiredness
  • Lack of appetite, anorexia and nausea
  • Low blood oxygen levels
  • Persistent cough
  • Prolonged hoarseness
  • Shortness of breath
  • Weight loss and weakness

According to a 2023 medical review, symptoms of sarcomatoid mesothelioma are nonspecific, which means patients often don’t report specific symptoms with the disease that may help identify it. Symptoms often resemble those of more common illnesses like bronchitis.

If you have any symptoms or a history of asbestos exposure, speak with a specialist as soon as possible. If you have a history of asbestos exposure, speak with your doctor about early screening. More treatment options may be available with an early mesothelioma cancer diagnosis.

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How Is Sarcomatoid Mesothelioma Diagnosed?

Sarcomatoid cell mesothelioma stain
A pathology stain showing sarcomatoid mesothelioma cells under a microscope.

When patients go to the doctor with mesothelioma symptoms, doctors order imaging tests such as X-rays or CT scans. If X-rays reveal abnormalities, they’ll collect a tissue sample for a biopsy. Another doctor reviews the sample under a microscope and creates a pathology report.

Doctors use biopsies to confirm a sarcomatoid mesothelioma diagnosis. Only a biopsy can show specific details such as cell type.

Pathology stains are chemical laboratory tests that make cell features stand out under a microscope. Sarcomatoid cells are long, narrow and shaped like spindles.

Doctors diagnose 300 to 600 new patients with this cell type yearly. About 98% of these patients have pleural mesothelioma and about 2% have peritoneal mesothelioma.

Understanding Your Pathology Report

Your pathology report describes the tumor cell type, biomarkers and cancer stage. Your doctor uses the findings to complete your diagnosis. Ask your doctor about your report and how it affects your treatment options.

Most patients don’t know their cell type when I initially speak with them. I help them review their pathology report and explain what sarcomatoid cell types are and what this means for them.

Patient Advocates can walk you through each section of the report to make sure you have a good understanding of what it says. They can answer questions about how a sarcomatoid diagnosis may impact treatment and prognosis.

Immunohistochemical markers, or biomarkers, can indicate how to treat your cancer. These markers are like flags telling your doctor which drugs work best. For example, if sarcomatoid cells in your tumor express high levels of PD-L1, that will appear when a pathologist stains them. Checkpoint inhibitor drugs such as Opdivo and Yervoy may be the most effective in this case.

Rare Sarcomatoid Cell Types

Rare sarcomatoid mesothelioma cell subtypes can provide information about your prognosis. These types come in three categories. Some may provide a better prognosis. Others can point to a higher chance of metastasis.

Rare Sarcomatoid Cells
  • Desmoplastic Mesothelioma. This sarcomatoid subtype is one of the most difficult to diagnose. With this cell type, doctors may be unable to track if your tumor is growing.
  • Lymphohistiocytoid Mesothelioma. These tumors contain inflammatory and immune cells. This can translate to more symptoms but also a better life expectancy.
  • Transitional Mesothelioma. This type grows and spreads like other subtypes. It consists of large, spindle-shaped cells that make the disease easier to diagnose.

These sarcomatoid mesothelioma subtypes are generally rare. They most often develop in the pleura of the lungs. Ask your physician whether there are any abnormalities in your pathology report. They can offer more information on your prognosis.

What Is the Survival Rate of Sarcomatoid Mesothelioma?

The median overall survival for sarcomatoid mesothelioma was 15 months with immunotherapy and 10.7 months with chemotherapy in a recent study. Each patient’s prognosis differs based on health, tumor location and metastasis. Doctors use data from the recent past to make prognosis estimates for sarcomatoid mesothelioma life expectancy. 

Patients with pleural sarcomatoid mesothelioma survive about five months. The average life expectancy for peritoneal mesothelioma patients is about 10 to 11 months after diagnosis. Women with the sarcomatoid type tend to live longer than men. 

The most impressive advancement for checkpoint blockade has been the demonstration that for people with sarcomatoid and biphasic mesothelioma, we can double survival with the combination of ipilimumab and nivolumab.

Characteristics of these cells contribute to the prognosis of sarcomatoid mesothelioma. Their shape causes them to break apart rather than stick together. This separation allows for metastasis, when the cancer cells travel to new areas and form tumors. Sarcomatoid cells also recur quickly after treatment. 

These factors make the cancer likely to return and spread after treatment. However, some sarcomatoid patients have lived for years thanks to breakthroughs in immunotherapy. New therapies available through clinical trials may work better for some patients.

Survivor Story
Survivor Story
Wally Rogers Sarcomatoid Mesothelioma

Immunotherapy Works Wonders for Sarcomatoid Mesothelioma Survivor

Following rounds of chemotherapy, Wally Rogers’ tumors began growing again. Diagnosed with sarcomatoid mesothelioma, his tumors were particularly difficult to treat. After connecting with a specialist who recommended immunotherapy, he began Keytruda. Follow-up tests showed an almost immediate effect on the hard-to-treat cancer. CT scans showed no sign of remaining tumor cells.

Read Wally’s Story

Treatment Options for Sarcomatoid Mesothelioma

Sarcomatoid mesothelioma treatment options include chemotherapy, immunotherapy, palliative care, radiation therapy, targeted therapy and surgery. Treatment options differ for each patient based on cancer stage, tumor extent and overall health. For example, surgery isn’t generally recommended because this cell type tends to recur quickly. However, surgery is considered when peritoneal patients respond to immunotherapy.

Recent research suggests immunotherapy may have long-lasting beneficial effects in the sarcomatoid patients who respond to the treatment. Tumor Treating Fields therapy or noninvasive electrical pulse treatment, however, hasn’t shown the same effectiveness for sarcomatoid tumors in recent research. Consulting a mesothelioma specialist at a top cancer center is the best way to learn all your options.

Sarcomatoid Mesothelioma Treatment
  • Chemotherapy: Patients with sarcomatoid mesothelioma who receive Alimta (pemetrexed) plus cisplatin or carboplatin chemotherapy have a median survival of 15 months.
  • Immunotherapy: Patient survival with the immunotherapy drugs Opdivo (nivolumab) and Yervoy (ipilimumab) improves an average of 4 months compared to chemotherapy alone.
  • Palliative Care: Less invasive chemotherapy and surgery can ease symptoms, slow tumor growth and improve breathing quality through palliative care.
  • Radiation Therapy: Radiation is often used alongside other therapies and has increased the 2-year life expectancy 30% for some mesothelioma patients.
  • Targeted Therapy: Targeted therapies such as AZD8186 are showing effectiveness for some cancers in clinical trials

“Sarcomatoid mesothelioma is a little less responsive to chemotherapy,” mesothelioma specialist Dr. Andrea Wolf of Mount Sinai Hospital told The Mesothelioma Center at Asbestos.com. “But from what we see from more recent data, it may be more responsive to immunotherapy. And we have additional treatment options for those patients.” 

Sarcomatoid patients may consider palliative care, which aims to relieve symptoms and improve quality of life. Only about 48% of mesothelioma patients who responded to The Mesothelioma Center’s 2023 survey reported taking advantage of palliative care.

Dr. Jacques Fontaine and Dr. Andrea Wolf
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Common Questions About Sarcomatoid Mesothelioma

Is sarcomatoid mesothelioma curable?

Sarcomatoid mesothelioma is generally considered incurable. Surgery isn’t typically recommended for sarcomatoid mesothelioma. Other treatments including immunotherapy, chemotherapy and radiotherapy are unlikely to be curative. There may be occasional instances of very long-term survival in sarcomatoid mesothelioma treated with immunotherapies.

Answered By: Anna Nowak, internationally renowned asbestos researcher and mesothelioma advocate

Where can I get treatment for sarcomatoid cell mesothelioma?

You can get sarcomatoid mesothelioma treatment from a mesothelioma specialist at a top treatment center. This cell type is more challenging to treat and requires an expert. Mesothelioma specialists work at the best cancer centers, which are often located in major metropolitan areas throughout the country.

Can sarcomatoid mesothelioma be prevented?

You can prevent sarcomatoid mesothelioma by avoiding asbestos exposure. Exposure tends to happen at job sites or from damaged materials containing asbestos. Find out whether you have asbestos-containing materials in your home. If you do, take steps to prevent exposure, such as hiring an abatement professional.

Is there any ongoing research on sarcomatoid mesothelioma?

Yes, researchers are working on novel ways to treat sarcomatoid mesothelioma. Some patients have found success with new immunotherapy drugs in clinical trials. You may be eligible to join a clinical trial and receive the latest medication that targets sarcomatoid cells. Ask your mesothelioma specialist which treatments are right for you.

Is sarcomatoid mesothelioma different from sarcomatoid carcinoma?

Yes, sarcomatoid mesothelioma and carcinoma are two different types of cancer with unique origins and characteristics. Sarcomatoid malignant mesothelioma is a subtype of mesothelioma. This cancer arises from the mesothelial cells that line the lungs, abdomen or heart. The sarcomatoid type involves spindle-shaped or elongated tumor cells. These cells resemble those in sarcoma, a cancer that arises from connective tissue.

Sarcomatoid carcinoma is a subtype of carcinoma. This cancer occurs in the epithelial cells that line various organs and tissues. It can develop in several organs, including the lungs, liver and pancreas. Treatment is often different between the two types based on location and stage.

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