What is Pleural Mesothelioma?
Pleural mesothelioma is a malignant cancer that develops in the pleura, the two layers of tissue that surround and protect the lungs.
Mesothelioma is caused by exposure to asbestos. People who worked with asbestos products are most at risk.
A long latency period of 20 to 50 years transpires between exposure and development of the cancer. It takes decades for asbestos to cause the genetic damage that leads to pleural mesothelioma.
Once the cancer develops, it progresses quickly. Unfortunately, the first symptoms of the cancer arise after tumors have progressed into an advanced stage of mesothelioma development. This is the primary reason the disease is often diagnosed too late for surgery to work.
While surgery is considered the best treatment to improve prognosis, it isn’t the only option. Other treatments can extend life expectancy, including chemotherapy, radiation therapy, immunotherapy, gene therapy and photodynamic therapy.
Clinical trials are testing and refining these therapies, and researchers are working hard to find better ways of controlling the disease. While there is no cure for pleural mesothelioma, many patients can live a long time with the cancer thanks to advances in treatment technologies.
What Causes Pleural Mesothelioma?
Pleural mesothelioma is primarily caused by exposure to asbestos, a mineral that was once widely used in many commercial and domestic products.
It generally takes years of repeated exposure to asbestos to become at risk of developing pleural mesothelioma. The people who develop the cancer usually worked with asbestos products throughout their career.
Sometimes the family members of asbestos workers develop pleural mesothelioma. Known as secondary exposure, this kind of exposure happens when workers unknowingly bring asbestos fibers home on their work clothes.
Asbestos fibers cause tissue inflammation and genetic damage to cells. Over time, the inflammation and genetic damage lead to cancerous changes in mesothelial cells. Once tumors begin to form, it doesn’t take long for mesothelioma to rapidly grow and spread.
What Are the First Signs of Pleural Mesothelioma?
- Difficulty breathing
- Shortness of breath
- Chest pain
- Dry cough
- Weight loss
- Night sweats
As mesothelioma progresses, more serious symptoms may develop such as difficulty swallowing, back pain and nerve pain.
Many patients may experience symptoms associated with pleural effusion, which is a buildup of fluid around the lungs. This condition may cause shortness of breath and a feeling of pressure inside the chest.
How Is Pleural Mesothelioma Diagnosed?
Primary care doctors often order a chest X-ray when patients present symptoms. Difficulty breathing and chest pain are the most common symptoms that bring patients to the doctor.
An X-ray may reveal something suspicious on or around the lungs, prompting the doctor to refer a patient to a pulmonologist, oncologist or local hospital for additional testing.
Tissue biopsies and advanced imaging scans are required to make an official pleural mesothelioma diagnosis. Tissue biopsies help doctors confirm the precise type of cancer present. Imaging scans — such as CT and PET scans — help stage how far along the cancer has progressed.
Stages of Pleural Mesothelioma
The most widely used method of staging is the Tumor, Node, Metastasis (TNM) system. The International Union Against Cancer and the American Joint Committee on Cancer have adopted this system.
Pleural mesothelioma cancer growth is categorized in four stages. As the stage number increases, the prognosis for mesothelioma becomes poorer and survival rates decrease.
- Stage 1: Cancer cells are only found in the pleural lining of one lung.
- Stage 2: Cancer cells have grown into nearby lymph nodes.
- Stage 3: Cancer cells have spread into nearby tissues and distant lymph nodes within the chest.
- Stage 4: Cancer cells have spread throughout the chest cavity and potentially to distant organs.
A patient’s stage of mesothelioma at diagnosis is the most important factor in determining treatment options.
Pleural Mesothelioma Treatment
Pleural mesothelioma treatment options include chemotherapy, surgery, radiation therapy and certain experimental therapies.
The most commonly administered chemotherapy drugs for pleural mesothelioma are carboplatin/cisplatin and pemetrexed. Recent studies have shown that the addition of a third drug, bevacizumab, improves survival in mesothelioma patients.
Approximately 80% of patients are diagnosed too late to qualify for surgery.
- Radiation Therapy
Radiation therapy is sometimes used following surgery to improve local control of tumors. However, studies do not show that the addition of radiation therapy results in longer survival.
- Experimental Therapies
Experimental therapies, including immunotherapy, gene therapy and photodynamic therapy, are available through clinical trials. Patients may be able to access immunotherapy drugs through compassionate use programs.
- Complementary Therapies
Many patients use complementary therapies in addition to these conventional cancer treatments. Known as integrative oncology, this approach uses safe complementary therapies to help ease the side effects of cancer treatment. Examples of complementary therapies include acupuncture, yoga and meditation.
Pleural Mesothelioma Doctors and Their Cancer Centers
- Abraham Lebenthal, M.D.
Lebenthal trained under mesothelioma treatment pioneer Dr. David Sugarbaker and has dedicated part of his career to helping veterans with mesothelioma. He splits his time operating at the VA Boston Healthcare System and Brigham and Women’s Hospital. He also teaches up-and-coming surgeons at Harvard Medical School.
- Raja Flores, M.D.
Flores is the chief of thoracic surgery and director of the Thoracic Surgical Oncology program at Mount Sinai Medical Center in New York. He is renowned for his surgical expertise and bedside manner. He helped pioneer the use of intraoperative chemotherapy for pleural mesothelioma. Flores is known for his low surgical complication rates and his friendly manner with patients.
- Robert Cameron, M.D.
Cameron is the pioneer of a surgical procedure for pleural mesothelioma known as pleurectomy and decortication, which keeps both lungs intact. He is the director of UCLA’s Comprehensive Mesothelioma Program. Cameron’s patients enjoy a higher quality of life post-surgery thanks to the preservation of both lungs. Cameron is involved in pleural mesothelioma research and improving surgical approaches for the cancer.
What Is the Prognosis for Pleural Mesothelioma?
The prognosis for most pleural mesothelioma patients is poor. The disease shortens life expectancy by an average of 10.6 years, according to a 2013 study published in the American Journal of Industrial Medicine.
What Factors Impact a Pleural Mesothelioma Prognosis?
- Stage: The cancer’s stage at diagnosis has the biggest impact on prognosis. Early stage patients have a better prognosis and may live for several years with mesothelioma. Last stage patients have a poor prognosis and live around one year.
- Location: Pleural mesothelioma is associated with a poorer prognosis compared to peritoneal mesothelioma, the second most common type of the cancer.
- Cell Type: Patients with epithelial cell type tumors live an average of 200 days longer than patients with sarcomatoid or biphasic cell types.
- Gender: Women have a much better chance of living longer with mesothelioma than men, and doctors believe hormonal differences are a factor.
- Age: Younger patients tend to live longer with mesothelioma than older patients.
- Treatment: Patients who elect treatment live at least a year. Those who decide to forego treatment have an average life expectancy of six months.
Pleural Mesothelioma Survival Rates
- 73% survived one year
- 23% survived three years
- 12% survived five years
- 4.7% survived 10 years
Improving prognosis involves working with a mesothelioma expert to get the best possible treatment.
Joining a clinical trial is a common option for patients who don’t respond well to first-line treatment. Innovative therapies — such as immunotherapy and gene therapy — are available through clinical trials.
Even though there is no cure for pleural mesothelioma, patients may improve their prognosis by working with an expert doctor and participating in clinical trials.