MESOTHELIOMA

Mesothelioma is a rare and aggressive cancer that affects the mesothelium, the protective lining covering many internal organs. These include:

Pleura: Surrounding the lungs.
Peritoneum: Encasing organs in the abdomen and pelvic area.
Pericardium: Enveloping the heart.
Tunica Vaginalis: Covering the testicles.

Although its prevalence is relatively low, mesothelioma is a severe and often deadly disease.

Causes

The primary cause of this condition in adults is past exposure to asbestos fibers and dust. About 70% to 80% of individuals with mesothelioma have a history of asbestos exposure, often through occupational settings. It typically takes over 20 years for symptoms to manifest after exposure.

In rarer cases, mesothelioma may develop following exposure to similar minerals like silica and erionite, a type of zeolite mineral linked to mesothelioma.

Researchers are investigating the role of genetics in this rare cancer development, as only a small proportion of individuals exposed to asbestos develop the disease.

Other potential causes being explored include exposure to chemicals, viral infections, and radiation. Radiation therapy, in particular, is associated with childhood mesothelioma.

Types of Mesothelioma

Mesothelioma can be categorized based on its cancerous nature and its location within the body:

Malignant Mesothelioma: Cancerous tumors.
- Subtypes include:
  - Pleural Mesothelioma.
  - Peritoneal Mesothelioma (also known as abdominal mesothelioma).
  - Pericardial Mesothelioma.
  - Mesothelioma of the Tunica Vaginalis Testis (also known as testicular mesothelioma).
Benign Mesothelioma: Non-cancerous tumors.

Mesothelioma can also be classified based on the type of cells forming the tumor:

Epithelioid: Common cells with a better prognosis.
Sarcomatoid: Less common cells with higher mobility and increased danger.
Biphasic: A mix of epithelioid and sarcomatoid cells

Prevalence

Mesothelioma is relatively uncommon, with an estimated 3,000 to 4,000 new cases diagnosed annually in the United States. It predominantly affects older adults, with the majority of cases occurring in individuals aged 65 and above. Men are more frequently diagnosed than women, likely due to higher rates of occupational exposure to asbestos. Among these cases, approximately 2,500 are diagnosed with malignant pleural mesothelioma.

Symptoms

Symptoms of this rare cancer can vary depending on the type of mesothelioma present. Some general symptoms may include:

Fever
Night sweats
Malaise (general feeling of being unwell)
Weakness
Unintended weight loss

Specific symptoms for each type of mesothelioma include:

Pleural Mesothelioma:
- Slowly worsening shortness of breath (dyspnea)
- Chest pain
- Difficulty swallowing (dysphagia)
- Chest lumps
- Pleural effusion (fluid on the lungs)
Peritoneal Mesothelioma:
- Abdominal pain
- Anemia
- Ascites (abnormal fluid collection)
- Diarrhea
- Loss of appetite and weight
- Nausea and vomiting
- Intestinal blockage
Pericardial Mesothelioma:
- Low blood pressure
- Abnormal heart rhythms
- Chest pain
- Difficulty breathing
Mesothelioma of Tunica Vaginalis Testis:
- Hydrocele (swelling in the scrotum)
- Scrotal lump
- Inguinal hernia
- Spermatocele (cyst in the epididymis)

Risk Factors

This rare cancer is strongly linked to exposure to asbestos, a mineral once widely used in various industries. While regulations now govern asbestos use, those exposed decades ago are still being diagnosed.

Demographics: Mesothelioma affects more men than women, with diagnoses most common among men aged 50 to 70.
Occupational Risk: Workers in industries such as construction, shipbuilding, mining, milling, and mechanics face increased risk due to asbestos exposure.
Military Veterans: Veterans may have been exposed to asbestos on military bases, ships, and during construction activities.
Childhood Mesothelioma: Asbestos exposure isn’t a factor, but children treated with radiation therapy for earlier cancers have a higher risk.

Several factors increase the risk of developing mesothelioma:

Age: Most cases occur in people aged 65 and older.
Gender: Men are at higher risk than women.
Family history: A history of this rare cancer in the family can increase risk.
Radiation exposure: Previous radiation therapy to the chest or abdomen may elevate the risk.

Diagnosis

Diagnosing this rare cancer can be challenging due to its nonspecific symptoms. Doctors use several methods to diagnose the disease:

Medical History and Physical Examination:

Your healthcare provider will review your medical history and conduct a physical examination, listening for specific symptoms and signs.

Diagnostic Tests:

Blood Tests: May be conducted to assess overall health and detect abnormalities.
Lung Function Tests: Measure how well your lungs are functioning.
Imaging Tests:
- Chest X-rays: Provide initial insights into lung health and potential abnormalities.
- Computed Tomography (CT) Scans: Offer detailed images of the chest and abdomen, aiding in tumor detection and evaluation.
- Positron Emission Tomography (PET) Scans: Assess metabolic activity within tissues, helping identify areas of concern.
- Magnetic Resonance Imaging (MRI) Scans: Less commonly used but may provide additional information in specific cases.
Biopsy: A tissue sample is collected and examined under a microscope to confirm the presence of mesothelioma cells.

Treatments

Treatment for this condition depends on the stage and location of the cancer and the patient’s overall health. Common treatments include:

Staging and Assessment

After the diagnosis, staging determines the extent of the disease progression. Higher stages indicate more advanced disease, such as Stage III or IV.

Treatment Options

Surgery:
- Surgical intervention may be considered, depending on the stage and location of the tumor.
- Malignant Pleural Mesothelioma: The most common type often treated with surgery, though less than one-third of patients are eligible.
- Surgical Approaches: These may involve tumor removal with or without adjunctive therapies like chemotherapy or radiation.
Chemotherapy and Radiation:
- If surgery is not an option, chemotherapy and/or radiation therapy are typically used to target and shrink the tumor.
- Combination Therapy: Often, a combination of chemotherapy and radiation is employed for enhanced efficacy.
Other Therapies:
- Experimental Treatments: Patients may have access to investigational treatments like biologic agents and antiangiogenic therapies.
- Antiangiogenic Therapy: Aims to disrupt the tumor’s blood supply, hindering its growth and spread.

Treatment approaches for mesothelioma vary depending on whether the tumor is benign or malignant.

Treatment for Benign Mesothelioma:
- Benign mesothelioma tumors do not spread to other parts of the body and can be surgically removed.
- Surgical Removal: Your healthcare provider may recommend surgical intervention to completely remove the tumor. This approach typically prevents recurrence.
- Additional Treatment: In some cases, chemotherapy may be recommended following surgery to target any remaining cancer cells.

Complications of Treatment

Despite the potential benefits of surgery and chemotherapy, they may pose risks and lead to complications such as:

Infection
Myocardial Infarction (Heart Attack)
Kidney Failure
Multi-Organ Failure
Prolonged Mechanical Ventilation

Home Care Tips

Managing this condition at home involves several strategies to improve quality of life:

Pain management: Using prescribed pain relievers and alternative therapies like acupuncture.
Nutritional support: Eating a balanced diet to maintain strength and energy.
Breathing exercises: To improve lung function and ease shortness of breath.
Emotional support: Seeking counseling or joining support groups.

Prevention

The prevention largely involves reducing asbestos exposure:

Avoid asbestos: Steer clear of materials containing asbestos, especially in older buildings.
Follow safety regulations: Adhere to workplace safety guidelines if you work in an industry with asbestos exposure.
Use protective equipment: Wear appropriate protective gear when handling asbestos.
Regular screenings: For individuals with a history of asbestos exposure, regular medical check-ups can help detect early signs of the disease.

Managing Side Effects

Chemotherapy and Radiation Side Effects: Discuss any side effects experienced with your healthcare team, as there may be strategies to alleviate discomfort.

Additional Common Questions

Fatality of Mesothelioma:
- While benign mesothelioma is non-fatal, malignant mesothelioma is almost invariably fatal due to its aggressive nature and limited treatment success.
Life Expectancy:
- Life expectancy varies based on mesothelioma type, individual health, and treatment response.
- Early detection and aggressive treatment may improve outcomes, but prognosis remains challenging.

When to See a Doctor

Seek medical attention if you experience persistent symptoms such as chest pain, shortness of breath, or unexplained weight loss, especially if you have a history of asbestos exposure. Early diagnosis can significantly improve treatment outcomes.

Outlook/Prognosis

The prognosis for this rare cancer is generally poor due to its aggressive nature and late diagnosis. However, early detection and advancements in treatment options can improve survival rates. Patients may live several years after diagnosis with appropriate care and treatment.

Sources

American Cancer Society. (2024).
Mayo Clinic. (2024).
National Cancer Institute. (2024).
Mesothelioma Research Foundation of America.
StatPearls
Canadian Cancer Society.
National Organization for Rare Disorders.