Pleural mesothelioma is a rare cancer of the pleura, the lining of the lungs. It is the most common form of cancer caused by asbestos.
Exposure to asbestos is the only scientifically verified cause of pleural mesothelioma.
Pleural mesothelioma is the most common type, accounting for 70-90% of all mesothelioma diagnoses.
The average life expectancy of pleural mesothelioma is 1 year.
Most patients are treated with a combination of surgery, chemotherapy and radiation.
Pleural mesothelioma is a form of mesothelioma that affects the lining of the lungs, called the pleura. Though only about 3,000 new cases of mesothelioma are diagnosed each year, about 70 – 90% of the new diagnoses are pleural mesothelioma. Since it is the most common form of the rare cancer, it is the most studied and has seen promising treatment advancements in recent years.
Though survival rates have been slightly improving, pleural mesothelioma patients still face a rather poor life expectancy, with only about 40% expected to survive more than a year after diagnosis.
- Cause // Asbestos inhalation
- Location // Lung/chest lining (pleura)
- Common Symptoms // Chest pain
Dyspnea (shortness of breath)
Pleural effusion (fluid buildup)
- Treatment // Surgery
- Prognosis // 6 – 12 months
What Causes Pleural Mesothelioma?
Asbestos exposure is the only definitive cause of pleural mesothelioma, as is the case with its other forms. Most often, pleural mesothelioma is caused by inhalation of asbestos fibers. Once inhaled, the durable fibers become lodged in the lining of the lung, which is made of two parts. The inner layer, known as the visceral surface, is a delicate membrane that covers the surface of each lung. The outer layer of the pleura is called the parietal surface and attaches to the chest wall. The asbestos fibers may become trapped in either layer, causing chronic inflammation and scar tissue that can develop into tumors over time.
Because the right lung is bigger, it generally suffers more damage than the smaller left lung. But many pleural mesothelioma patients often have a sheath-like formation of tumors across the pleura, as the tumors grow quickly and can easily spread throughout the lung cavity. If the disease becomes more advanced, the tumors may also spread to other organs, including the abdomen, diaphragm, lymph nodes and heart.
Diagnosing the Symptoms of Pleural Mesothelioma
Like the other forms of mesothelioma, pleural mesothelioma is difficult to diagnose partially due to indistinct symptoms. At times, this rare cancer has even been confused for the flu, laryngitis, pneumonia, chronic obstructive pulmonary disease (COPD) and other more common lung or respiratory conditions. It has also been misdiagnosed as other lung cancers, like adenocarcinoma.
- Chest or lower back pain
- Persistent coughing
- Coughing up blood (hemoptysis)
- Difficulty swallowing (dysphagia)
- Shortness of breath (dyspnea)
- Fluid around the lungs (pleural effusion)
- Hoarseness or difficulty speaking
- Blood clots (less common)
Patients experiencing any of these symptoms should talk to their doctor about any possible exposures to asbestos in the past. Even if it happened years ago, no amount of exposure is considered safe, and it can help your doctor test for mesothelioma or other asbestos-related diseases.
With these nonspecific symptoms and the long latency period associated with all forms of mesothelioma, some patients have to wait weeks or even months before receiving a proper pleural mesothelioma diagnosis. Though a diagnosis will generally begin with a variety of imaging tests to determine the presence of cancer, a biopsy is currently the only method to confirm pleural mesothelioma.
The biopsy will consist of taking samples of pleural tissue for testing. The doctor may also perform a thoracentesis, or a pleural tap, which is a slightly invasive procedure that removes fluid from the pleura for analysis. A pathologist will determine if the cells are malignant, and if pleural mesothelioma is confirmed they will also be able to decipher the cell type.
Pleural Mesothelioma Stages
Unlike the other forms of mesothelioma, pleural mesothelioma has several staging systems that oncologists rely on to determine the progression of the disease. The most widely used and accepted, however, is the TNM Staging System, which stands for Tumor, Nodule, and Metastasis. Doctors will use the system to score an area for each category, which will collectively make up the stage.
Refers to disease which is confined to the primary site, or site of origin. The lymph nodes are free of disease and there are no metastases present. Most often, treatment for stage I mesothelioma consists of surgical resection, or removal, of the disease.
Refers to disease which is confined to one site. While the lymph nodes are still free of disease and there are no metastases present, the tumor extends into the deeper pleural surfaces on the same side as the tumor as well as at least one of the following: the diaphragm or the lung.
Refers to disease which either has spread to lymph nodes on the same side as the tumor; or, a tumor which is extensive and involves the deeper pleural surfaces as well as at least one of the following: chest wall, thoracic fascia, sac around the heart, or mediastinal fat. The tumor is still considered resectable by surgery. There is no metastasis present.
Refers to disease in which one of the following occurs: the tumor is too extensive for surgery, there is distant lymph node involvement on the opposite side from the tumor, or there is distant metastasis present.
Doctors may also use the Brigham staging system, which focuses on a tumor’s ability to be surgically removed, or the Butchart system, which focuses on the extent of the primary tumor and in general is viewed as more limiting. Regardless of the staging system used, the stage of pleural mesothelioma has a large impact in determining what treatments a patient is eligible for and their prognosis. A stage 1 patient, for instance, will have more treatment options like curative surgery, compared to a stage 4 patient whose mesothelioma has likely spread to other parts of the body or the tumors are too extensive for removal.
Pleural Mesothelioma Prognosis
Like the other types of mesothelioma, pleural mesothelioma patients also face a poor prognosis. Though it is the most common and most researched, doctors still face difficulties in diagnosing and treating the disease. Advancements in treatment and ongoing clinical trials have provided hope in finding new, effective treatments like immunotherapy, which has already shown promise in extending survival for some patients. On average, pleural mesothelioma patients have a life expectancy of about one year, though a number of factors can influence an individual’s prognosis like stage, cell type, and the patient’s age.
Pleural Mesothelioma Survival Rate
|Years of Survival||Survival Rate|
The cell type (epithelioid, sarcomatoid and biphasic) can also have a great impact on prognosis. Most pleural mesothelioma cases have epithelioid cells, which account for 50-70% of all mesothelioma cases. Epithelial cells have the best prognosis because they respond best to treatment.
Biphasic cells are the second most common, and consists of a mix of epithelial and sarcomatoid cells. Prognosis for patients showing biphasic cells can vary, dependent on which of the two cell types is more dominant. Sarcomatoid cells are the least common, difficult to diagnose (especially early on), and have a higher chance of spreading. As such, sarcomatoid mesothelioma typically has the worst prognosis.
Pleural Mesothelioma Prognosis Based on Cell Type
|Cell Type||Life Expectancy|
Pleural Mesothelioma Treatments
Most pleural mesothelioma patients are treated with a multimodal plan, which often consists of some combination of surgery, chemotherapy and radiation. There are also many ongoing clinical trials studying the effectiveness of different combination therapies, and new treatments. Immunotherapy, in particular, has shown promise for many kinds of cancer, including pleural mesothelioma. Researchers have seen promising results, with some patients extending their survival by months or even years.
For early stage pleural mesothelioma patients, there are two curative surgery options that are both considered rather aggressive and invasive. The goal of either option is to remove as many of the tumors and cancer cells as possible to help relieve symptoms and improve life expectancy, but both surgeries face potentially serious risks and complications.
|Pleurectomy Decortication||Extrapleural Pneumonectomy|
For patients who aren’t candidates for surgery or as part of a combination therapy, chemotherapy is another tool often used to treat pleural mesothelioma. Though a variety of chemotherapy drug combinations have been used to treat pleural mesothelioma, the standard of care has remained Alimta and Cisplatin for many years. Alimta is currently the only chemotherapy drug to be FDA approved as a treatment for malignant pleural mesothelioma. With this treatment, studies have found median survivals of 12 – 16 months. Other chemotherapy combinations, like Avastin in combination with the standard chemotherapy treatment, have had similar results, sometimes even extending survival to 19 months.
Radiation is also often used in combination with surgery or chemotherapy, and in some cases has been applied as a palliative treatment. One recent study explored pleural mesothelioma patients treated with radiation therapy, whether multimodally or individually, over the course of 10 years. The researchers found radiation therapy improved overall survival regardless of how it was implemented in the treatment plan, and should be a tool utilized more regularly to continue improving survival rates.
Clinical trials and research in new therapies and different combinations of even current standard treatments have helped make a lot of progress in improving quality of life and overall survival for mesothelioma patients. In particular, immunotherapy has shown some success in treating pleural mesothelioma, and continues to be an important aspect of research. Certain types of immunotherapy, like the checkpoint inhibitor Keytruda, have enabled some patients to achieve longer survival, and with further study will hopefully become even more effective.
So far, these treatments are only available in clinical trials. Because of the rarity of the disease, it can be difficult for some patients to find or learn about what clinical trials are available and if they are eligible for any of the studies. Working with a mesothelioma specialist can help you learn more about clinical trials and emerging treatments, and determine if any of these options are right for you.
Pleural Mesothelioma Specialists
Finding a mesothelioma specialist is an important aspect of your care, as they have experience evaluating an individual case and treating the disease, which can ultimately help improve your prognosis. Many of these doctors are also involved in research or heading clinical trials testing the latest, promising treatments.
Pleural Mesothelioma Treatment Costs
The costs of a pleural mesothelioma diagnosis can add up quickly. Imaging scans and biopsies just to confirm a diagnosis can cost even upwards of $5,000 for one test, and treatment costs only continue to rise. Recent estimates show a single cancer drug can cost well over $120,000 for a year of treatment, and may increase by even nearly 11% per year.
With such large medical bills looming on top of everyday living costs and the potential secondary costs of this diagnosis, like travel and lodging, it’s critical that patients and their loved ones take time to make a financial plan. Everything from understanding your health insurance policy to finding some programs that can also help cover treatment costs can help offset this significant financial burden.
Mesothelioma victims should also understand their legal right to file a claim and possibly receive compensation to help cope with these medical expenses. Some states have a statute of limitations of just one year, so it’s important to discuss your rights and legal options with a mesothelioma lawyer as soon as possible.