Mesothelioma: Causes, Symptoms, Diagnosis, and Treatment Options

A diagnosis of mesothelioma is a life-changing event, often accompanied by a great deal of uncertainty and fear. Because this is a rare cancer, it is natural to have many questions about the disease and its treatment. This comprehensive guide is designed to provide clear, compassionate, and authoritative information to help you understand what mesothelioma is, how it is diagnosed and treated, and what to expect on your journey. We will use simple, patient-friendly language to ensure you feel informed and empowered to make the best decisions about your health.

What Is Mesothelioma?

Mesothelioma is a rare and aggressive cancer that starts in the mesothelial cells. These specialized cells form a protective lining called the mesothelium, which covers most of the body’s internal organs. This thin layer of tissue protects organs by providing a smooth, slick surface that allows them to move against each other without friction.

There are four main types of mesothelioma, named for where the cancer originates:

• Pleural Mesothelioma: This is the most common type, accounting for about 80% to 90% of all cases. It develops in the pleura, the lining that surrounds the lungs and the inside of the chest cavity. Although it is in the chest, it is important to know that pleural mesothelioma is not a lung cancer and is treated differently.
• Peritoneal Mesothelioma: This is the second most common type, making up about 10% to 15% of cases. It develops in the peritoneum, the lining of the abdomen.
• Pericardial Mesothelioma: This is an extremely rare type that develops in the pericardium, the lining of the heart.
• Testicular Mesothelioma: This is the rarest form, which develops in the lining of the testicles.

What Are the Causes and Risk Factors for Mesothelioma?

Unlike many other cancers, the primary cause of mesothelioma is well-established. The overwhelming majority of cases are linked to a single cause: exposure to asbestos.

● Asbestos Exposure:

Asbestos is a group of naturally occurring minerals that were used widely in construction and industry for their heat and fire-resistant properties. When asbestos is disturbed, it releases tiny, needle-like fibers into the air. When these fibers are inhaled or, less commonly, swallowed, they can get lodged in the mesothelium. Over decades, these fibers cause inflammation and scarring, which can lead to the development of cancerous tumors. The time between initial exposure and a diagnosis of mesothelioma can be anywhere from 20 to 50 years.

Other Risk Factors:

• Genetic Predisposition: In very rare cases, a genetic mutation (such as a change in the BAP1 gene) can increase a person’s risk of developing mesothelioma, even with limited asbestos exposure.
• Radiation Therapy: A history of receiving radiation therapy to the chest for other cancers has been linked to a slightly increased risk of mesothelioma.

It is important to remember that most people who were exposed to asbestos do not develop mesothelioma. However, even brief or low-level asbestos exposure can increase risk, though the greatest risk is seen with prolonged and high-intensity exposure.

What Are the Symptoms of Mesothelioma?

The long latency period of mesothelioma means that symptoms may not appear for decades after exposure. When they do appear, they are often vague and can be mistaken for other, less serious conditions. This makes early detection a significant challenge.

Common Symptoms of Pleural Mesothelioma:

• Shortness of Breath (Dyspnea): This is the most common symptom, caused by fluid buildup (pleural effusion) between the lungs and the chest wall.
• Chest Pain: A dull, persistent ache in the chest.
• A Persistent Cough: A dry, persistent cough that doesn’t go away.
• Pain in the Shoulder or Upper Arm: This can happen if the tumor presses on nerves.
• Unexplained Weight Loss: Losing weight without trying.
• Fatigue: Feeling unusually tired or a general lack of energy.

Common Symptoms of Peritoneal Mesothelioma:

• Abdominal Pain and Swelling: Caused by fluid buildup in the abdomen (ascites).
• Loss of Appetite: Feeling full after eating only a small amount.
• Nausea and Vomiting
• Changes in Bowel Habits: Such as diarrhea or constipation.

If you have a history of asbestos exposure and experience any of these symptoms, it is crucial to see a doctor promptly.

How Is Mesothelioma Diagnosed?

Diagnosing mesothelioma can be a complex process because its symptoms mimic many other common diseases. The diagnosis often begins with a physical exam and a detailed discussion of your medical and occupational history, especially any potential asbestos exposure.

Diagnostic Steps and Tests:

1. Imaging Scans:

• Chest X-ray: Often the first test, which can show signs of fluid buildup in the chest or thickening of the pleura.
• CT (Computed Tomography) Scan: A CT scan provides detailed images of the chest and abdomen to help doctors see the exact size and location of the tumors.
• PET (Positron Emission Tomography) Scan: A PET scan uses a radioactive sugar that is absorbed by fast-growing cancer cells, which makes them light up on the scan. This can help find cancer that has spread to other parts of the body.

2. Biopsy (The Only Definitive Test): A biopsy is the only way to confirm a diagnosis of mesothelioma. A small sample of the suspicious tissue or fluid is removed and sent to a lab to be examined by a pathologist. There are several types of biopsies:

• Fluid Biopsy: Fluid cytology (thoracentesis or paracentesis) can detect malignant cells, but in mesothelioma it is often non-diagnostic. A tissue biopsy is usually required for confirmation.
• Needle Biopsy: A needle is inserted through the skin to get a small tissue sample from the tumor.
• Surgical Biopsy: In some cases, a small surgical procedure (thoracoscopy or laparoscopy) is needed to get a larger tissue sample for an accurate diagnosis.

3. Blood Tests: While not definitive, some blood tests can look for certain biomarkers (like soluble mesothelin-related peptides, or SMRP) that may be elevated in people with mesothelioma.

Staging and Grading of Mesothelioma

The stage and grade of the cancer are crucial for determining the treatment plan and predicting a patient’s prognosis.

Grading:

Mesothelioma is typically classified into three cell types based on its appearance under a microscope. This is often more important for prognosis than a numerical grade.

• Epithelioid: The most common and least aggressive cell type. It responds best to treatment.
• Sarcomatoid: The most aggressive cell type. It is less responsive to treatment.
• Biphasic: A mix of both epithelioid and sarcomatoid cells.

Staging:

This four-stage TNM system is primarily standardized for pleural mesothelioma; staging systems for peritoneal mesothelioma differ and are less universally applied.

• Stage I: The cancer is localized to the pleura on one side of the chest and has not spread to lymph nodes or other organs.
• Stage II: The cancer has started to spread into nearby tissues, such as the lung or diaphragm, but has not yet reached distant lymph nodes.
• Stage III: The cancer has spread more extensively to nearby structures like the chest wall or diaphragm and may have spread to nearby lymph nodes, but not to distant parts of the body.
• Stage IV: The cancer has spread to distant parts of the body (metastasis), such as the liver, bones, or brain.

What Are the Treatment Options for Mesothelioma?

Treatment for mesothelioma is complex and requires a multidisciplinary approach. Because the cancer is often diagnosed at a later stage, treatment is focused on prolonging life and improving a patient’s quality of life.

1. Surgery

Surgery is a primary treatment option for early-stage mesothelioma and can also be used to relieve symptoms in advanced stages.

• Extrapleural Pneumonectomy (EPP): This is a very aggressive surgery that involves removing the affected lung, the pleura, parts of the diaphragm, and the lining of the heart. It is only an option for a small number of patients who are in good overall health and have early-stage disease.
• Pleurectomy/Decortication (P/D): This less aggressive surgery involves removing the pleura and any visible tumors while leaving the lung intact. It has a lower risk of complications and is often a better option for a wider range of patients.
• Cytoreduction with HIPEC: For peritoneal mesothelioma, a surgeon will remove all visible tumors from the abdominal cavity. This is often followed by a heated chemotherapy wash that is poured directly into the abdomen to kill any remaining cancer cells.

2. Medical Treatment (Chemotherapy, Targeted Therapy, Immunotherapy)

• Chemotherapy: Chemotherapy (usually pemetrexed with cisplatin or carboplatin) remains a standard first-line systemic treatment, though survival benefits are modest.
• Immunotherapy: Immunotherapy has revolutionized the treatment of mesothelioma. These drugs, such as checkpoint inhibitors, help a patient’s own immune system recognize and attack the cancer cells. Checkpoint inhibitor immunotherapy (such as nivolumab plus ipilimumab) has become a new standard option for many patients with unresectable pleural mesothelioma.
• Targeted Therapy: These drugs work by targeting specific genes or proteins that help cancer cells grow and spread. At present, no targeted therapies are standard of care in mesothelioma, though clinical trials are ongoing, particularly for patients with BAP1 or other gene alterations.

3. Radiation Therapy

Radiation therapy uses high-energy rays to kill cancer cells. It is not typically used as a standalone cure for mesothelioma, but it is a valuable part of the treatment plan.

• Adjuvant Radiation: Radiation may be given after surgery to kill any remaining cancer cells and reduce the risk of recurrence.
• Palliative Radiation: In advanced cases, radiation can be used to relieve painful symptoms, such as chest pain or shortness of breath.

4. Proton Therapy

While not a standard treatment, proton therapy is an advanced form of radiation that uses protons instead of X-rays. Because protons can be precisely aimed to deliver a high dose of radiation directly to the tumor while sparing nearby healthy organs like the heart and spinal cord, it is being studied as a potential treatment for mesothelioma, particularly after surgery.

Prognosis and Survival Rates for Mesothelioma

The prognosis (the likely outcome of the disease) for mesothelioma can vary greatly. It is important to remember that these statistics are averages and cannot predict an individual’s outcome.

Prognostic Factors:

• The most important factors affecting prognosis are the stage of the cancer at diagnosis, the cell type (epithelioid, sarcomatoid, or biphasic), the patient’s overall health, and the type of treatment received.

Survival Rates:

• Survival rates for mesothelioma are difficult to generalize. For pleural mesothelioma, the average 5-year survival rate is around 12%. However, for peritoneal mesothelioma, the rate is significantly higher, at around 65%, due to more effective surgical treatments.

Screening and Prevention of Mesothelioma

There is no routine screening test for mesothelioma in the general population. The most effective way to prevent the disease is to avoid asbestos exposure.

Prevention Strategies:

• Avoid Asbestos: Be aware of the presence of asbestos in older buildings, especially during renovations. If you work in a high-risk industry, use proper protective equipment.
• Quitting Smoking: While smoking does not cause mesothelioma, it significantly increases the risk of developing asbestos-related lung cancer and other respiratory illnesses.

Early Detection:

• Know Your Symptoms: If you have a history of asbestos exposure, be vigilant for any of the symptoms listed above and see a doctor promptly.

For International Patients: A Seamless Journey to Apollo Hospitals

Apollo Hospitals is a leading medical destination for international patients seeking high-quality and affordable cancer care. Our dedicated International Patient Services team is here to ensure your entire experience is as smooth and comfortable as possible, from your initial inquiry to your return home.

Our Services for International Patients Include:

• Travel and Visa Assistance: We will provide you with a visa invitation letter and help with travel arrangements.
• Airport Transfers: We will arrange for a car to pick you up from the airport.
• Personalized Care: A dedicated patient coordinator will be your single point of contact, assisting with hospital admission, language interpretation, and any other needs you may have.
• Accommodation: We can assist you with booking suitable accommodation for you and your family near the hospital.
• Post-Treatment Follow-up: We will stay in touch with you after your return home to ensure a smooth recovery.

About Apollo Proton Cancer Centre

Apollo Proton Cancer Centre (APCC) is the first proton therapy centre in India. APCC has a fully integrated treatment suite that offers the most advanced treatment in surgical, radiation, and medical oncology procedures. True to the Apollo Pillars of Expertise and Excellence, the Centre brings together a powerful team of clinicians renowned globally for cancer care.

At Apollo Proton Cancer Centre (APCC), we combine advanced technology with globally renowned clinical expertise to deliver superior outcomes and improved quality of life to our patients.