Malignant Mesothelioma

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Overview

Mesothelioma is a condition wherein cancer forms in the thin protective layer of tissues (mesothelium) present on the majority of the internal organs. Mesothelioma is aggressive cancer, which is also very challenging to treat. In most cases, mesotheliomas are detected in their advanced stages.

Exposure to the chemical asbestos significantly increases one’s risk of developing mesothelioma, and it is for this reason, mesothelioma is also called ‘asbestos cancer’.

Types

Based on the region of their occurrence, mesotheliomas are classified into:

1. Pleural Mesothelioma: Mesothelioma that occurs in the tissues layering the lungs is called pleural mesothelioma. Pleural mesothelioma is the most common mesothelioma type.
2. Peritoneal Mesothelioma: This mesothelioma type affects the tissues that layer the abdomen.
3. Pericardial Mesothelioma: Pericardial mesothelioma affects the mesothelium of the heart. This is an extremely rare condition.
4. Testicular Mesothelioma: This cancer type affects the cells present in the outer layer of the testicles (tunica vaginalis). Testicular mesothelioma is the rarest form of mesothelioma.

Be it of any origin, mesotheliomas are extremely aggressive and can readily damage the surrounding tissues and organs.

Symptoms

The symptoms of this condition differ based on the location of its origin. Pleural mesothelioma, which is the most common type of mesothelioma, can have the following symptoms:

Chest pain
Shortness of breath caused due to excess accumulation of fluid in the pleura
Extreme tiredness
Painful cough
Formation of unusual masses of tissues under the skin of the chest
Unintentional weight loss

Peritoneal mesothelioma may cause the following symptoms:

Abdominal pain and swelling
Lethargy
Appetite loss
Unintentional weight loss
Nausea
Change in bowel movements – constipation and diarrhoea

Pericardial mesothelioma may cause chest pain and breathing difficulties, and testicular mesothelioma, on the other hand, may lead to the swelling of the testicle.

Courses

The exact cause for the occurrence of mesothelioma is unknown. However, a few major risk factors have been identified:

Exposure to Asbestos: Asbestos exposure is the primary risk factor for mesothelioma. Those who have had prolonged exposure to asbestos are at a higher risk of getting mesothelioma. Living with someone who works with asbestos can also increase the risk of this disease.
Exposure to Zeolites: Zeolites are a class of minerals that are chemically related to asbestos, and prolonged exposure to this mineral can also increase one’s risk of developing mesothelioma.
A Family History of Mesothelioma: Having a close relative who is diagnosed with mesothelioma is also a risk factor for this disease.
History of Radiation Therapy to the Chest Region: Those who have received radiation therapy for cancers in the chest region could also be at a higher risk of developing this disease.

Diagnosis

The doctor recommends various tests if an individual is suspected to have mesothelioma. Following are the multiple methods used for the detection and diagnosis of mesothelioma:

a. Medical History Assessment and Physical Exam: When a patient first presents himself with the symptoms of mesothelioma, the doctor assesses his/her medical history in order to understand the cause behind the symptoms. Later, he/she may also conduct a physical exam in order to find swelling, lumps and other symptoms that are associated with mesothelioma.

b. Tumour Markers: If mesothelioma is suspected, then the doctor may recommend a blood test to look for mesothelioma markers, namely fibulin 3, osteopontin and soluble mesothelin-related peptides (SMRPs). However, additional tests are necessary for a conclusive diagnosis.

c. Fluid Sample Test: Fluid build-up is one of the common symptoms of mesothelioma. Therefore, the doctor may recommend collecting the sample of the fluid and getting it examined for the presence of mesothelioma cells. To collect the samples, a thin needle is inserted through the skin into the area where fluid build-up is observed.

d. Imaging Tests: Imaging tests, such as PET CT scans, MRI scans or CT scans may be recommended by the doctor to receive more data on the abnormal masses found. These scans also help in detecting if the mesotheliomas have spread to nearby organs. These tests are necessary for disease staging, treatment planning and also in evaluating the patient’s response to the treatment.

e. Biopsy: Biopsy is the only way to obtain a definitive diagnosis of mesothelioma. During this procedure, the cell samples from the area that is suspected to have cancer are collected and sent to the laboratory for a microscopic examination. The cell samples may be collected by inserting a fine needle or during the surgery.

Once the confirmed diagnosis is received, the disease staging is done with the help of advanced imaging, and the treatment planning is done accordingly.

Treatment

Treatment planning for mesothelioma is made based on various factors, namely the type, the stage of the disease, the grade, the age of the patient and his/her overall condition.

Three main treatment options available for mesothelioma include surgery, radiation therapy and chemotherapy.

a. Surgery: Surgery is one of the main lines of the treatment of mesothelioma. Surgery could either be performed with a curative intent or to manage the symptoms caused by the disease in the advanced stages. One of the following surgical procedures may be recommended by the doctor depending on the stage of the disease.

Surgery for Pleural Mesothelioma:

Wide Local Excision: This surgery removes the tumour along with a small portion of the healthy tissues surrounding it, called the margin.
Pleurectomy and Decortication: During this procedure, the pleura or the thin layer of tissue surrounding the lungs is removed along with the lining of the chest wall (on the side where cancer is present). Additionally, the pleura that covers the mediastinum and diaphragm is removed.
Extrapleural pneumonectomy: This procedure involves the removal of the entire lung and a portion of the diaphragm along with the lining of the lung (pleura) and heart (pericardium). This surgery is often combined with other treatment approaches, namely radiation therapy and chemotherapy.
Pleurodesis: Pleurodesis is a treatment approach, wherein the lung is permanently attached to the chest wall. The pleural gap between the lung and the chest wall is removed during this surgery, ensuring that fluid or air does not build up between the layers.

Surgery for Peritoneal Mesothelioma:

Peritonectomy or Debulking: Peritonectomy is a surgical procedure where the surgeon tries to remove as much of the disease as possible. At times, the procedure could involve the removal of a small portion of the intestine too.
HIPEC Treatment: During this procedure, a heated mixture of powerful anticancer or chemo drugs is directly pumped into the abdominal cavity and made to sit there for some time. This helps in destroying the mesothelioma cells present in the abdominal cavity. In most cases, HIPEC treatment is given after the debulking procedure.
Omentectomy: The omentum is a fatty tissue layer that lines various organs present in the abdominal region. Because peritoneal cancers frequently extend to this tissue, it may be removed as part of peritoneal mesothelioma surgery.

Surgery for Pericardial Mesothelioma:

Pericardiectomy: This surgery removes a portion or the entire pericardium to stop the mesothelioma from spreading. This surgery helps in extending the life span and easing the symptoms in mesothelioma patients.
Pericardiocentesis: This procedure removes the excess fluid that has built up in the sac around the heart. It helps in relieving the symptoms in patients with advanced mesothelioma.

Surgery for Testicular Mesothelioma:

Orchiectomy: Patients who are diagnosed with testicular mesothelioma could be treated with orchiectomy, wherein one or both of the testicles are removed along with the spermatic cord. This procedure could also be followed by lymphadenectomy, which removes the affected lymph nodes close to the tumour.

Owing to their rare occurrence, testicular mesotheliomas are often diagnosed in later stages and could also be misdiagnosed.

b. Radiation Therapy: Radiation therapy is also used to treat some types of mesotheliomas. This treatment approach involves delivering high-energy radiation beams to the tumour in order to destroy the cancer cells or stop them from multiplying. There are two ways to deliver the radiation for mesothelioma – internally and externally. During external beam radiation therapy, the radiation is delivered from an external source; whereas, during internal radiation therapy or brachytherapy, a radiation source (radioactive substance) is placed inside or very close to the tumour; the radiation emitted by this source destroys the mesothelioma cells. Needles, seeds, catheters or wires may be used to deliver the radiation source to the tumour’s location.

Frequently Asked Questions

1. Is mesothelioma treatable?

In most cases, mesothelioma is diagnosed in the advanced stages, and this often leads to a poor prognosis. However, if it is diagnosed in the early stages, it can be treated with decent clinical outcomes.

Since mesothelioma often causes non-specific symptoms, it is often misdiagnosed. Therefore those who are high-risk individuals for this disease should consider a second opinion if they are diagnosed with cancer. This is important in order to receive a correct diagnosis.

2. Is mesothelioma difficult to diagnose?

Due to its rare occurrence and the non-specific symptoms it causes, mesothelioma can be relatively challenging to diagnose.

However, we have multiple tests available today that can help us in detecting this condition accurately. Various diagnostic methods recommended by the doctors for mesothelioma include blood tests, fluid sample tests, imaging tests and biopsies.

3. Does mesothelioma cause pain?

The most common and earliest symptom of mesothelioma is pain. As fluids build up and tumours grow and press against key organs, breathing, coughing and digestion can also become painful. Increased pressure and pain in the chest and abdomen can also be caused by fluid build-up.

In these cases, patients should talk to their treating doctor who can put them in touch with the pain management specialists, who can help in the management of pain and other discomfort caused due to the disease.

4. What is palliative therapy for mesothelioma?

If a patient has advanced mesothelioma, treating the condition successfully may be difficult, and therefore, the doctor may recommend palliative therapy.

Palliative therapy does not treat mesothelioma; instead, it aims at extending the patient’s life span, easing the pain and other discomfort caused due to the disease and improving the overall quality of life for the patient.

5. How can I prevent mesothelioma?

Avoiding Prolonged Exposure to Asbestos:Asbestos exposure is the biggest risk factor for mesothelioma, and bringing down your exposure to this harmful chemical can significantly bring down your mesothelioma risk. Following are the categories of individuals who are at a higher risk of getting mesothelioma:

miners
construction workers
factory workers
insulation manufacturers and installers
plumbers
railroad and automotive workers
ship manufacturers

These individuals should wear the appropriate safety gear and follow all safety protocols that are recommended for those working with asbestos.

Avoid Zeolite Exposure:Getting exposed to zeolites on a regular basis can also increase your mesothelioma risk. Therefore, reduce your exposure to this mineral.

If you consider yourself a high-risk individual for mesothelioma, you should talk to your doctor who can help you with the best practices to reduce the risk of developing this condition.