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Mesothelioma | Everything you need to know.

Mesothelioma | Everything you need to know.

10 mins

mesothelioma

Mesothelioma is a rare and aggressive cancer that develops in the mesothelium—a thin layer of tissue that lines many of the body’s internal organs. Although it most commonly affects the lining of the lungs (pleura), it can also develop in the abdominal lining (peritoneum), the lining around the heart (pericardium), or even the lining of the testicles (tunica vaginalis). Often referred to as malignant mesothelioma, this disease has also been known by alternative names such as “mesothelioma” or “malignant pleural mesothelioma” (when referring to the chest cavity) en.wikipedia.org.

Due to its strong association with asbestos exposure, mesothelioma is sometimes considered a “sentinel” cancer that signals the harmful effects of asbestos. While the disease is notoriously difficult to treat and has a poor prognosis overall, advances in diagnosis and treatment are gradually offering hope to patients.

In this article, we explore the definition, alternative names, causes, symptoms, diagnostic methods, treatment options, available support resources, prognosis, possible complications, indications for seeking medical attention, and preventive measures related to mesothelioma.

1. Definition and Alternative Names

What Is Mesothelioma?

Mesothelioma is a type of cancer that arises from mesothelial cells. These cells form the mesothelium, a protective membrane covering internal organs. Depending on its location, mesothelioma may be classified into several types:

Pleural Mesothelioma: Affects the pleura, the lining of the lungs and chest wall. This is the most common form, accounting for approximately 75–80% of all cases.
Peritoneal Mesothelioma: Develops in the peritoneum, the lining of the abdominal cavity.
Pericardial Mesothelioma: Occurs in the pericardium, the sac that surrounds the heart.
Testicular Mesothelioma: Rarely, mesothelioma can develop in the tunica vaginalis, the lining around the testicles.

Because the cancer originates in the mesothelial tissue, it is sometimes simply called “mesothelioma” or “malignant mesothelioma” to distinguish it from benign mesothelial conditions. In clinical discussions, the term “malignant mesothelioma” is used to emphasize the cancerous and aggressive nature of the disease en.wikipedia.org.

Alternative Names and Terminology

Malignant Mesothelioma: Emphasizes the cancerous nature of the disease.
Pleural Mesothelioma: Specifically refers to tumors affecting the lung lining.
Peritoneal/Abdominal Mesothelioma: Indicates cancer developing in the abdominal lining.
Pericardial Mesothelioma: Refers to the rare form affecting the heart’s lining.
Testicular Mesothelioma: The rarest form, affecting the tunica vaginalis.

Understanding these terms is important because treatment and prognosis can vary based on the mesothelioma type.

2. Causes and Risk Factors

Primary Cause: Asbestos Exposure

The overwhelming majority of mesothelioma cases—over 80%—are linked to asbestos exposure. Asbestos is a naturally occurring mineral known for its heat resistance, durability, and insulating properties. These qualities made it a popular material in construction, shipbuilding, and manufacturing from the early to mid-20th century en.wikipedia.org.

How Asbestos Causes Mesothelioma

When asbestos-containing materials are disturbed during activities like demolition or maintenance, tiny asbestos fibers become airborne. Once inhaled or ingested, these fibers can lodge in the mesothelial tissue. Over decades (typically 20–50 years), the chronic irritation and inflammation caused by these fibers can lead to DNA damage and ultimately result in malignant transformation of the mesothelial cells.

Other Causes and Contributing Factors

While asbestos exposure is by far the most important cause, mesothelioma can also be linked to:

Erionite Exposure: Erionite is a naturally occurring zeolite mineral with properties similar to asbestos. In some regions (such as Cappadocia in Turkey), environmental exposure to erionite has been associated with high rates of mesothelioma.
Radiation Therapy: Previous radiation treatment to the chest or abdomen has been identified as a potential risk factor for developing mesothelioma.
Genetic Predisposition: Inherited mutations—most notably in the BAP1 gene—may increase an individual’s susceptibility to mesothelioma, even at lower levels of asbestos exposure.
Infection with SV40: Although controversial, early studies suggested that simian virus 40 (SV40) might contribute as a cofactor in mesothelioma development. However, more recent research has largely discredited a direct causal link
webmd.com
Low-Level or Indirect Asbestos Exposure: Even brief or secondary exposure (such as fibers carried home on a worker’s clothing) can increase risk.

Occupational and Environmental Risk Factors

Occupational exposure is the most common route of asbestos contact. Individuals in the following occupations are at higher risk:

Construction workers, insulation installers, and demolition crews.
Shipyard and maritime workers.
Miners and millers involved in asbestos extraction and processing.
Automotive mechanics (due to asbestos in brake linings).
Factory workers involved in manufacturing asbestos-containing products.
Military personnel, particularly those who served in shipyards.

Environmental exposure can occur when living in older buildings with asbestos-containing materials or near asbestos mines.

3. Symptoms

General Overview

Symptoms of mesothelioma often develop slowly and can mimic less serious conditions, which makes early diagnosis challenging. Depending on the type of mesothelioma, symptoms may vary:

Pleural Mesothelioma: Typically presents with respiratory symptoms.
Peritoneal Mesothelioma: Often associated with abdominal symptoms.
Pericardial Mesothelioma: Involves heart-related symptoms.
Testicular Mesothelioma: May present with scrotal masses.

Symptoms by Mesothelioma Type

Pleural Mesothelioma (Lung Lining)

Common symptoms include:

Shortness of Breath: Often due to fluid buildup (pleural effusion) that compresses the lung.
Chest Pain: Persistent pain that can worsen with breathing or coughing.
Chronic Cough: A dry cough that may become persistent over time.
Difficulty Swallowing: In some cases, tumors may press on the esophagus.
Fatigue and Weight Loss: General symptoms as the cancer progresses.
Pleural Effusion: Accumulation of fluid in the chest, leading to further breathing difficulties.

Peritoneal Mesothelioma (Abdominal Lining)

Symptoms typically involve the abdomen:

Abdominal Pain and Swelling: Often due to ascites (fluid accumulation in the abdomen).
Bloating and Distension: Noticeable increase in abdominal girth.
Loss of Appetite and Weight Loss: As the disease affects the digestive organs.
Nausea and Vomiting: Resulting from intestinal blockage or irritation.
Changes in Bowel Habits: Such as constipation or diarrhea.

Pericardial Mesothelioma (Heart Lining)

Although rare, symptoms can include:

Chest Pain: Often related to the pericardium.
Irregular Heartbeat (Arrhythmia): Due to tumor involvement.
Shortness of Breath: Secondary to fluid accumulation or impaired heart function.
Fatigue and Weakness: As the heart struggles to pump effectively.

Testicular Mesothelioma

The rarest form, with symptoms including:

Scrotal Mass or Lump: Often painless and discovered incidentally.
Swelling of the Testicle: May cause discomfort over time.
Changes in Testicular Size or Consistency: Not always painful but warrant evaluation.

Early Versus Advanced Symptoms

In the early stages, mesothelioma may cause only mild or nonspecific symptoms, leading many individuals to delay seeking medical care. By the time symptoms become pronounced, the disease is often in an advanced stage, which complicates treatment options.

4. Diagnostic Exams and Tests

Given the nonspecific nature of early symptoms, a combination of diagnostic tests is usually required to confirm mesothelioma.

Medical History and Physical Examination

The diagnostic process typically begins with a thorough medical history:

Asbestos Exposure History: Detailed information regarding occupational or environmental exposure.
Symptom Review: Documenting the onset, duration, and severity of symptoms.
Physical Examination: Checking for signs like decreased breath sounds, abnormal chest wall findings, or abdominal distension.

Imaging Studies

Imaging tests are critical for visualizing abnormalities in the chest or abdomen:

Chest X-ray: Often the first imaging test performed; it may reveal pleural thickening or fluid accumulation.
Computed Tomography (CT) Scan: Provides detailed cross-sectional images of the chest, abdomen, or pericardium, helping to assess tumor size and spread.
Magnetic Resonance Imaging (MRI): Useful for evaluating the extent of tumor invasion, particularly for surgical planning.
Positron Emission Tomography (PET) Scan: Helps detect metabolic activity in tumors and can be combined with CT for better localization.
Ultrasound: Often used to guide fluid drainage procedures such as thoracentesis or paracentesis.

Laboratory Tests

Laboratory tests can support the diagnosis:

Blood Tests: Although no blood test can diagnose mesothelioma definitively, tests for biomarkers such as soluble mesothelin-related peptides (SMRPs), fibulin-3, and osteopontin may be elevated in mesothelioma patients
mayoclinic.org
.
Pulmonary Function Tests: Assess lung capacity and function, which may be affected by pleural effusion.

Biopsy Procedures

A biopsy is essential for a definitive diagnosis:

Needle Biopsy: Often guided by CT or ultrasound, a needle is used to extract tissue samples.
Thoracoscopy: A minimally invasive procedure in which a thoracoscope (a thin, lighted tube) is inserted through a small incision in the chest to visualize and sample the pleura.
Laparoscopy: Similar to thoracoscopy but used to sample tissue from the peritoneum.
Open Surgical Biopsy: In cases where less invasive methods are inconclusive, a thoracotomy or laparotomy may be performed to obtain larger tissue samples.

Immunohistochemistry

Once tissue is obtained, immunohistochemical staining is used to differentiate mesothelioma from other cancers (such as lung adenocarcinoma). Key markers include:

Calretinin: Often positive in mesothelioma.
WT1: A marker that supports mesothelial origin.
Cytokeratin 5: Commonly expressed.
Negative Markers: Such as CEA (carcinoembryonic antigen) help rule out other malignancies.

Staging

Staging helps determine the extent of disease spread and is critical for treatment planning. The TNM (Tumor, Node, Metastasis) system is commonly used:

Stage I: Cancer is localized to the mesothelial lining.
Stage II: Spread to nearby structures or lymph nodes.
Stage III: Involvement of neighboring tissues.
Stage IV: Distant metastasis.

For pleural mesothelioma, specific staging systems (often based on the International Mesothelioma Interest Group recommendations) are used, while peritoneal and pericardial mesotheliomas are staged less uniformly due to their rarity.

5. Treatment Options

Treatment for mesothelioma is challenging due to its aggressive nature and often advanced stage at diagnosis. Options are tailored to the individual based on the mesothelioma type, stage, patient health, and personal preferences. Most treatment plans are multimodal, involving a combination of therapies.

Surgical Options

Surgery is considered for patients with early-stage mesothelioma and may involve:

Extrapleural Pneumonectomy (EPP): Removal of the affected lung, part of the diaphragm, pericardium, and pleura. It is a radical surgery that aims for complete tumor resection.
Pleurectomy/Decortication (P/D): Removal of the pleural lining and as much tumor as possible while sparing the lung. This procedure is less radical than EPP and may offer a better quality of life.
Peritonectomy: For peritoneal mesothelioma, the surgical removal of parts of the peritoneum, often combined with heated intraperitoneal chemotherapy (HIPEC).

Chemotherapy

Chemotherapy uses cytotoxic drugs to kill cancer cells. The standard regimen for pleural mesothelioma includes:

Pemetrexed: An antifolate drug that interferes with cell division.
Cisplatin or Carboplatin: Platinum-based drugs that cause DNA damage. Chemotherapy can be administered before (neoadjuvant) or after (adjuvant) surgery, or as a primary treatment when surgery is not an option.

Radiation Therapy

Radiation therapy uses high-energy beams to target and destroy cancer cells:

Curative Radiation: Rarely used as a sole modality due to the diffuse nature of mesothelioma.
Palliative Radiation: Aims to relieve pain and reduce tumor size, particularly to manage symptoms such as chest pain or fluid buildup.
Post-Surgical Radiation: Often employed after surgery to target residual microscopic disease.

Immunotherapy

Immunotherapy has emerged as a promising treatment option:

Checkpoint Inhibitors: Drugs like nivolumab (Opdivo) and ipilimumab (Yervoy) have been approved for mesothelioma treatment. They work by boosting the immune system’s ability to recognize and destroy cancer cells
mesotheliomahope.com
.
Clinical Trials: Ongoing studies are investigating other immunotherapeutic agents and combinations to further improve outcomes.

Targeted Therapy and Experimental Treatments

Researchers are actively studying new treatments, including:

Targeted Therapy: Drugs designed to block specific molecules involved in tumor growth.
Tumor Treating Fields (TTF): A novel approach using electric fields to disrupt cancer cell division.
Gene Therapy: Experimental treatments aimed at correcting genetic abnormalities in mesothelioma cells.
Photodynamic Therapy (PDT): Uses light-sensitive drugs activated by laser light to kill cancer cells.

Palliative Care

For advanced-stage mesothelioma, the primary goal is symptom management and quality of life improvement:

Pain Management: Medications, nerve blocks, or procedures to alleviate chronic pain.
Fluid Drainage Procedures: Thoracentesis or paracentesis to relieve symptoms from fluid buildup.
Nutritional and Psychological Support: Addressing the physical and emotional challenges of the disease.
Hospice and End-of-Life Care: Providing comfort care when curative treatment is no longer feasible.

Multimodality Therapy

Many patients benefit from a combination of treatments (surgery, chemotherapy, and radiation) to maximize outcomes. The decision is individualized, with multidisciplinary teams (oncologists, surgeons, radiologists, and palliative care specialists) working together to design the optimal treatment plan.

6. Prognosis

Mesothelioma generally has a poor prognosis, though outcomes vary depending on several factors:

Survival Statistics

Overall Survival: For malignant pleural mesothelioma, the median survival is typically between 12 and 21 months.
Five-Year Survival Rate: In the United States, the five-year survival rate is around 8–12%, although patients with early-stage disease or epithelioid histology (the most common type) tend to have a somewhat better outlook
en.wikipedia.org
.
Peritoneal Mesothelioma: Patients treated with cytoreductive surgery combined with HIPEC have reported median survival times extending beyond five years in some studies.
Pericardial Mesothelioma: Due to its rarity and aggressive nature, median survival is typically shorter (around 10 months).

Factors Affecting Prognosis

Stage at Diagnosis: Early-stage mesothelioma offers a better chance for long-term survival.
Histological Subtype: Epithelioid mesothelioma generally has a better prognosis than sarcomatoid or biphasic types.
Patient Age and Overall Health: Younger, healthier patients tend to have more treatment options and better outcomes.
Completeness of Surgical Resection: Achieving complete removal of the tumor (R0 resection) is associated with improved survival.

While the overall prognosis remains guarded, ongoing advances in treatment and early detection strategies are slowly improving survival outcomes.

7. Possible Complications

Mesothelioma and its treatments can lead to various complications, which may further impact quality of life:

Disease-Related Complications

Pleural Effusion: Fluid buildup in the chest, which can worsen breathing difficulties and increase the risk of infection.
Ascites: In peritoneal mesothelioma, fluid accumulation in the abdomen can cause discomfort, swelling, and digestive issues.
Tumor Invasion: As tumors grow, they may invade nearby structures such as the chest wall, diaphragm, or lymph nodes, leading to pain and functional impairment.
Metastasis: Although mesothelioma primarily remains localized to the mesothelium, it can spread (metastasize) to other parts of the body, including the bones, liver, and other organs.

Treatment-Related Complications

Surgical Risks: Major surgeries like EPP carry significant risks, including infection, bleeding, and respiratory complications.
Chemotherapy Side Effects: Nausea, vomiting, kidney dysfunction, hearing loss, and neuropathy can occur.
Radiation Side Effects: Radiation may cause skin irritation, fatigue, and, in some cases, damage to surrounding healthy tissue.
Immunotherapy Reactions: Immune-related adverse events such as colitis, dermatitis, or pneumonitis may develop.

Managing these complications is an integral part of the overall treatment plan and often involves supportive and palliative care measures.

8. Indications for Seeking Medical Attention

Early detection of mesothelioma is critical to improving treatment outcomes. You should consider seeking medical advice if you:

Have a History of Asbestos Exposure: If you or a family member has worked in high-risk industries (e.g., construction, shipbuilding, mining) or you have lived in an older building with asbestos-containing materials.
Experience Persistent Respiratory Symptoms: Such as a chronic cough, shortness of breath, chest pain, or unexplained respiratory infections.
Notice Unexplained Weight Loss or Fatigue: These can be subtle signs of an underlying cancer.
Develop Abdominal Symptoms: In cases of peritoneal mesothelioma, persistent abdominal pain, bloating, or changes in bowel habits should be evaluated.
Have Unexplained Fluid Accumulation: Both pleural effusions and ascites warrant further investigation.
Are Concerned About Your Family’s Exposure: Family members of asbestos-exposed workers should be aware of potential secondary exposure risks.

Early consultation with a healthcare provider—ideally one with expertise in asbestos-related diseases—can help facilitate timely diagnosis and intervention.

9. Preventive Measures

While mesothelioma cannot be cured once it develops, most cases are preventable by reducing exposure to asbestos and other harmful agents.

Avoiding Asbestos Exposure

Workplace Safety: Workers in industries with potential asbestos exposure should adhere strictly to occupational safety guidelines, including wearing protective clothing and respirators.
Asbestos Abatement: In older buildings, professional asbestos abatement should be performed prior to renovation or demolition. Homeowners should consult certified professionals rather than attempting DIY asbestos removal.
Public Awareness: Increased education on the risks of asbestos and safe handling practices is critical. Employers and regulatory bodies should provide regular training and updates on asbestos hazards.

Government Regulations and Guidelines

Exposure Limits: Agencies such as the U.S. Occupational Safety and Health Administration (OSHA) and the Environmental Protection Agency (EPA) have set exposure limits to minimize the risk of asbestos-related diseases
en.wikipedia.org
.
Bans on Asbestos Use: Many countries have banned or severely restricted the use of asbestos in building materials and industrial products.
Screening Programs: Although there is no universally accepted screening program for mesothelioma, at-risk individuals (those with known asbestos exposure) may benefit from periodic imaging tests and biomarker evaluations.

Personal and Community Preventive Measures

Regular Health Check-ups: Individuals with known exposure should have routine evaluations, including imaging studies if symptoms develop.
Educational Campaigns: Community health organizations and government agencies should continue to raise awareness about asbestos risks.
Legislative Advocacy: Support policies that enforce safe handling and removal of asbestos from public spaces and residential areas.

10. Support Groups and Resources

Dealing with a mesothelioma diagnosis can be overwhelming, but many organizations provide emotional, educational, and sometimes financial support for patients and their families.

National and International Organizations

Mesothelioma Applied Research Foundation (MARF): Offers patient resources, research updates, and support group information.
Asbestos Disease Awareness Organization (ADAO): Provides advocacy, education, and support services for individuals affected by asbestos-related diseases.
National Organization for Rare Disorders (NORD): Contains a comprehensive rare disease database and links to mesothelioma support groups
rarediseases.org
.
Cancer Support Community: Provides support groups, counseling, and various services to help cancer patients and their families cope.
American Cancer Society: Offers information on mesothelioma, treatment options, and local support programs.

Online Communities and Forums

Mesothelioma Hope: An online resource that connects patients with specialists and legal support while offering a wealth of educational materials.
Health Forums and Social Media Groups: Many patients find support and share personal experiences through online communities, which can provide comfort and practical advice.

Legal and Financial Assistance

Patients diagnosed with mesothelioma may be eligible for compensation due to past asbestos exposure. Legal assistance organizations can help:

File Asbestos Claims: Many firms specialize in mesothelioma lawsuits, helping patients secure compensation for treatment costs and lost income.
Access Asbestos Trust Funds: Various funds have been established to compensate victims of asbestos exposure.
Workers’ Compensation: For those who were exposed during their employment, workers’ compensation benefits may be available.

11. Conclusion

Mesothelioma remains a challenging and aggressive cancer with a poor overall prognosis. However, understanding its definition, causes, symptoms, and diagnostic methods is crucial for early detection and effective management. The disease is most strongly linked to asbestos exposure, making preventive measures and strict occupational safety guidelines key to reducing its incidence.

Patients who suspect they have been exposed to asbestos—and who develop persistent respiratory, abdominal, or cardiac symptoms—should seek prompt medical attention. Early diagnosis, although difficult, can significantly improve treatment options and potentially extend survival.

Advances in treatment modalities, including surgery, chemotherapy, radiation therapy, and especially newer immunotherapeutic approaches, are offering hope to patients even in advanced stages. Multimodality treatment plans, tailored to the individual’s specific disease characteristics and overall health, are now the standard of care in specialized centers.

In addition to medical treatment, the role of comprehensive support services cannot be overstated. Emotional, legal, and financial support are critical components of the holistic care approach for mesothelioma patients and their families. Numerous organizations and online communities are available to provide the needed resources and comfort during this challenging time.

Preventing mesothelioma is possible through rigorous efforts to eliminate asbestos exposure. Government regulations, workplace safety protocols, and public education are key pillars in the fight against this asbestos-related disease.

While mesothelioma continues to pose a significant public health challenge worldwide, ongoing research and clinical trials hold promise for improved survival rates and, ultimately, better outcomes for patients. With increased awareness, early detection, and a commitment to preventive measures, we can hope to see a future with reduced incidence of this devastating disease.