What is Pleural Mesothelioma?

The Pleura: Understanding the Affected Area

The pleura is a crucial part of the respiratory system, consisting of two layers:

• Visceral Pleura: The inner layer that covers the lungs.
• Parietal Pleura: The outer layer that lines the chest wall and diaphragm.

Between these two layers is a small space known as the pleural cavity, which contains a thin film of fluid that allows the lungs to move smoothly during breathing. Pleural mesothelioma occurs when asbestos fibers are inhaled and become lodged in the pleura, leading to chronic inflammation, scarring, and eventually the development of cancerous cells.

Causes of Pleural Mesothelioma

The primary cause of pleural mesothelioma is exposure to asbestos, a group of naturally occurring minerals that were widely used in various industries throughout the 20th century for their heat-resistant properties. When asbestos-containing materials are disturbed, they release tiny fibers into the air. These fibers can be easily inhaled and become trapped in the pleura. Learn more about what causes mesothelioma.

Asbestos Exposure

• Occupational Exposure: Most cases of pleural mesothelioma are linked to occupational exposure in industries such as construction, shipbuilding, manufacturing, and mining, where asbestos was commonly used.
• Secondary Exposure: Family members of workers exposed to asbestos can also be at risk through secondary exposure, where asbestos fibers are brought home on clothing, hair, or skin.
• Environmental Exposure: In some cases, people living near asbestos mines or factories have developed pleural mesothelioma due to environmental exposure. Find out more about how much exposure to asbestos is dangerous.

Symptoms of Pleural Mesothelioma

Pleural mesothelioma symptoms often take decades to appear after the initial exposure to asbestos, which complicates early diagnosis. Symptoms typically become noticeable as the cancer progresses and include:

• Chest Pain: Persistent pain in the chest or lower back area, often described as sharp or stabbing.
• Shortness of Breath: Caused by pleural effusion (a buildup of fluid in the pleural cavity) or the thickening of the pleura.
• Cough: A chronic, dry cough that does not go away and may worsen over time.
• Fatigue: Generalized weakness and tiredness, which can be debilitating.
• Unexplained Weight Loss: A significant and unintentional loss of weight.
• Difficulty Swallowing (Dysphagia): In some cases, tumors can press on the esophagus, making swallowing painful or difficult.

Because these symptoms are non-specific and can resemble those of other respiratory conditions, pleural mesothelioma is often misdiagnosed in its early stages. For more details, see common symptoms of mesothelioma.

Diagnosis of Pleural Mesothelioma

Diagnosing pleural mesothelioma is challenging due to its rarity and the non-specific nature of its symptoms. A thorough diagnostic process typically involves several steps:

Imaging Tests

• X-rays: Initial imaging to check for abnormalities in the chest, such as pleural thickening or fluid buildup.
• CT Scans: Provide detailed cross-sectional images of the chest, helping to identify the size and location of tumors.
• PET Scans: Used to detect cancerous cells by highlighting areas of high metabolic activity.

Biopsy

• Needle Biopsy: Involves using a needle to extract a small sample of tissue from the pleura for examination under a microscope.
• Thoracoscopy: A minimally invasive procedure where a camera and surgical instruments are inserted into the chest to obtain tissue samples directly from the pleura.

Pathology Tests

• Histopathology: Examination of the biopsy sample to determine the presence and type of cancer cells. Pleural mesothelioma is typically classified into three histological subtypes: epithelioid, sarcomatoid, and biphasic (a combination of the two).

Blood Tests

• Biomarkers: While not definitive, certain biomarkers in the blood, such as mesothelin-related peptides, may support the diagnosis of pleural mesothelioma. Learn more about diagnosing mesothelioma.

Treatment Options for Pleural Mesothelioma

Treatment for pleural mesothelioma depends on several factors, including the stage of the disease, the patient’s overall health, and the specific characteristics of the cancer. Common treatment options include:

Surgery

• Extrapleural Pneumonectomy (EPP): A radical surgery that involves the removal of the affected lung, part of the diaphragm, the pleura, and nearby lymph nodes. It is usually considered in early-stage patients who are otherwise healthy.
• Pleurectomy/Decortication (P/D): Involves removing the pleura and any visible tumors while preserving the lung. This surgery is less invasive than EPP and is often preferred for patients with limited disease.

Chemotherapy

• Systemic Chemotherapy: The use of drugs, typically a combination of pemetrexed and cisplatin, to kill cancer cells or stop their growth. It is the standard treatment for patients who are not candidates for surgery.
• Intraperitoneal Chemotherapy: In some cases, heated chemotherapy drugs are directly administered into the pleural cavity to target the cancer more effectively. Discover more about how chemotherapy works for mesothelioma.

Radiation Therapy

• External Beam Radiation: Focuses high-energy rays on the affected area to kill cancer cells and reduce tumor size. Radiation is often used in combination with surgery or chemotherapy to enhance treatment effectiveness.

Immunotherapy

• Immune Checkpoint Inhibitors: Newer treatments that help the body’s immune system recognize and fight cancer cells. These therapies are being studied in clinical trials and show promise for treating pleural mesothelioma.

Palliative Care

• Symptom Management: For patients with advanced disease, palliative care focuses on relieving symptoms and improving quality of life. This may include procedures to drain fluid from the pleural cavity, pain management, and respiratory therapy.

Prognosis and Survival Rates

The prognosis for pleural mesothelioma is generally poor, with a median survival time of 12 to 21 months after diagnosis. However, factors such as the stage of the disease at diagnosis, the patient’s overall health, and response to treatment can significantly influence outcomes. Early detection and aggressive treatment can improve survival rates, and ongoing research continues to explore new therapies that may extend life expectancy. For more information, see the prognosis for someone with mesothelioma.

Conclusion

Pleural mesothelioma is a serious and often deadly disease caused primarily by asbestos exposure. Its symptoms can take decades to appear, and its diagnosis is often delayed until the disease is advanced. Despite the challenges in treating pleural mesothelioma, advances in medical research and new treatment options offer hope for improved outcomes. Understanding the nature of this disease, its causes, and available treatments is essential for those affected by pleural mesothelioma and their families.

Sources:

• National Cancer Institute - Pleural Mesothelioma Overview
• American Cancer Society - Detailed Guide on Pleural Mesothelioma
• Centers for Disease Control and Prevention (CDC) - Asbestos and Mesothelioma