Mesothelioma is one of the rarest forms of cancer in the human body. An estimated 3,000 people are diagnosed with mesothelioma each year in the United States. With a 5-year survival rate, more than 43,000 people worldwide die from the disease each year.
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What is Mesothelioma?
Mesothelioma is a rare and aggressive form of cancer found in the mesothelium lining of the lungs, stomach, and heart. The mesothelium is a protective lining that covers the internal organs of the human body. The function of this layer of cells is to secrete a lubricating fluid that enables the smooth movement of the tissues and the underlying organs. Mesothelioma cancer is a type of cancer that affects the lining of the lungs while the abdominal lining and the sac near the heart are rarely affected.
Malignant Mesothelioma is a type of cancer that most people know of only because law firms representing its victims advertise aggressively on television. This cancer starts in a thin layer of protective tissue called the mesothelium that lines several major body cavities and covers most of the body’s internal organs like lungs, stomach, and heart. The rarest form of mesothelioma is pericardial mesothelioma, which involves the sac surrounding the heart.
There are two major types of mesothelioma cells: Epithelial and Sarcomatoid. Sometimes both of these cell types can be present. The sarcomatoid type is rarer and occurs in only about 15% of cases; it gives a poorer prognosis. In very rare cases, mesothelioma can originate from benign, non-malignant cells. This so-called benign mesothelioma can be cured surgically. When the cells of the mesothelium undergo changes that become malignant, they can spread to other parts of the body.
Types of Mesothelioma, based on location
There are four primary types of mesothelioma cancer based on the location where a tumor first develops: pleural (lungs), peritoneal (abdomen), pericardial (heart), and testicular. Mesothelioma can start in the membrane surrounding the lungs, heart, or abdomen, with the lungs being the most common site of the disease. Approximately three-quarters of all cases start in the chest cavity.
Types of Mesothelioma Tumors, based on malignancy
Another way to categorize mesothelioma is based on whether the tumor is malignant or not. A malignant tumor indicates that it is harmful, and if left untreated, will cause sickness and death.
- Malignant Mesothelioma is a common form of mesothelioma and can be fatal if left untreated. Since mesothelioma has a long latency period, it can be challenging to diagnose, making the malignancy that much more dangerous. However, even if a patient is diagnosed with malignant mesothelioma, there is still hope, especially if the disease is caught early. With the right treatment schedule, survivors can live for years after being diagnosed.
- Benign Mesothelioma is relatively rare and occurs in only a few limited cases. For example, Well-Differentiated Papillary Mesothelioma (WDPM) is commonly considered a benign form of mesothelioma. It is generally easier to treat than the deadly form of cancer, and in most cases, it can be treated successfully.
Causes of Mesothelioma
Mesothelioma predominantly affects one population group: those who have had prolonged exposure to asbestos.
These are a group of minerals that contain tiny fibers that are immune to heat and chemicals. As a result, this material does not permit the conduction of electricity. The tiny fibers make their way into the human body when they are released into the environment during the manufacturing or construction process.
Asbestos exposure accounts for nearly 75% of the cases of mesothelioma cancer, making asbestos exposure the most common cause of the disease. This includes mainly the people who are directly affected by working with asbestos but can also affect family members who are regularly exposed to asbestos fibers brought into the home and people living near asbestos mines. More rarely, it can occur in people who have undergone high-dose radiation treatment to the chest or abdomen or who have had exposure to minerals that are related to asbestos. Continuous exposure to this dangerous substance can lead to mesothelioma cancer and can be life-threatening if they are not treated on time.
One of the puzzling facts about mesothelioma cancer is that many people who have had years of asbestos exposure never develop the disease, while others with very little exposure do. It isn’t known why this happens, although there may be a genetic predisposition.
Common Symptoms of Mesothelioma
Due to its long latency period, the symptoms of mesothelioma can manifest twenty to fifty years after exposure to asbestos. Some of the common symptoms include:
- Shortness of breath
- Chest Pain
- Bowel Obstruction
- Weight Loss
- Abdominal swelling and pain
- Lumps under the skin of the chest or abdomen
The initial symptoms can be easily confused as other ailments, so people tend to ignore or neglect these signs.
Symptoms of pleural mesothelioma can include a sharp pain along the side of the chest, shortness of breath, fever and cough, tiredness, and excessive sweating. Peritoneal mesothelioma can be diagnosed if you complain of abdominal pain, constipation, swelling in the abdomen region, followed by nausea. Note that these symptoms are caused due to mesothelioma and can often be confused with other common ailments like a common cold or general malaise.
Diagnostic Procedures for Mesothelioma
Blood tests and X-rays are used to diagnose malignant mesothelioma in the peritoneum.
- Imaging tests are used to locate tumors inside the body. Tests like X-rays, CT scans, PET scans, and MRIs are most commonly used.
- Blood-marker tests are performed to determine the presence and type of cancer. It is also used to analyze the best course of treatment for each patient.
- The biopsy is the process of extracting a tissue or fluid sample from a tumor or its surrounding area. These samples are examined under a microscope to determine cell type and is the only way to diagnose mesothelioma definitively.
Many doctors have never encountered mesothelioma due to its rarity. This results in a high percentage of misdiagnoses when compared to other cancers. It is commonly misdiagnosed because the symptoms are typical to illnesses such as the common cold, flu, and pneumonia. To prevent misdiagnosis, patients should seek a second opinion from a separate mesothelioma specialist.
Misdiagnosis also occurs in two other ways. Mesothelioma is mistaken for other cancers, including lung cancer or some cancers in the abdominal region. Moreover, mesothelioma can be staged (1-4) incorrectly, leading to limited treatment and recovery options for patients. (Source: Mesothelioma Guide)
Treatment of Mesothelioma Cancer
While no cure currently exists, mesothelioma patients can usually improve their prognosis through some form of treatment. Even in cases where improving lifespan is not viable, palliative care and alternative therapies are available to help reduce the pain and suffering from symptoms.
Because this aggressive cancer is usually only diagnosed when it has become advanced, treatment options are limited. In cases where standard treatments do not work, mesothelioma patients may also be able to try experimental treatments through clinical trials.
In those cases, surgery is used to remove cancer if it hasn’t spread widely, to decrease fluid build-up in the abdomen, and sometimes for the removal of an affected lung. Surgery may also be used to remove the tissue surrounding the heart or abdomen, but this is a way to help relieve painful symptoms and will not cure cancer.
Systemic chemotherapy can help shrink or stop mesothelioma from growing and is sometimes used on patients who have cancerous cells and growths that cannot be removed surgically. Sometimes chemotherapy drugs can be administered directly to the abdominal cavity to reach cancer without harming healthy cells. Chemotherapy may be followed by radiation to pinpoint and treat specific areas of cancer or simply to alleviate painful symptoms of the disease.
There are also clinical trials investigating gene therapy, biological therapy (using the body’s immune system to battle cancer), and targeted therapy, which uses certain drugs to target cancer cells in certain parts of the body specifically.
Standard Mesothelioma Treatments
Important considerations in determining a mesothelioma treatment plan include the cancer stage, primary site affected, and cell type. Treatment options also depend on whether the cancer is localized to the chest or has spread to the chest wall, diaphragm, or lymph nodes, as well as your age and overall health. The three standard therapies used to treat mesothelioma are surgery, chemotherapy, and radiation.
- Surgery is recommended for patients with an early-stage mesothelioma diagnosis, as it is possible to remove all or most of the tumors. Depending on the tumor location, it may include removing the mesothelial lining, one or more lymph nodes, part or all of a lung or other organ.
- Chemotherapy drugs work by attacking fast-growing cells, such as cancer cells. Often used in conjunction with surgery, chemotherapy can kill any remaining mesothelioma cells that the surgeon was unable to remove physically.
- Radiation Therapy is used to target mesothelioma tumors. It can shrink the tumors, thereby making it easier to be surgically removed. Depending on the tumor location, the radiation can be delivered using an external or an internal source.
In many cases, specialists recommend a multimodal approach that uses a combination of these three types of treatment. Multimodal treatment typically consists of a primary treatment used in combination with neoadjuvant therapy or adjuvant treatment. An example of a multimodal approach might include:
- Neoadjuvant therapy
- Helper treatment: Radiation to shrink the tumor size
- Primary treatment: Surgery to remove the tumor
- Adjuvant therapy
- Primary treatment: Surgery to remove the tumor
- Helper treatment: Chemotherapy to kill any remaining tumor cells
Mesothelioma can be prevented by reducing exposure to asbestos. This entails providing awareness to workers regarding the hazards associated with asbestos and how to monitor the air for the presence of asbestos particles in the environment. People who might be exposed to high levels of asbestos at work include miners, factory workers, insulation manufacturers and installers, railroad and automotive workers, shipbuilders, gas-mask manufacturers, plumbers, and construction workers. If there is a chance of on-the-job exposure, such as during the renovation of old buildings, one should use all protective equipment and safety procedures designed for working around asbestos.
Intact, undisturbed materials containing asbestos generally do not pose a health risk. They may pose a risk if they are damaged, are disturbed in some way, or deteriorate over time and release asbestos fibers into the air. By federal law, all US schools are required to inspect materials with asbestos regularly and to have a plan in place for managing them.