• The main risk factor is exposure to asbestos. In fact, about 70% to 80% of patients with malignant mesothelioma report a history of asbestos exposure.
• Occupational asbestos exposure includes miners, ship builders, automobile manufacturing, insulation manufacturing, railroad workers or construction workers.
• Exposure can also occur in household environments from exposure to asbestos containing products including insulation materials, brake linings, roof shingles, flooring products, cement, textiles, and paint.
• There is an estimated 8% lifetime risk of asbestos workers developing mesothelioma. In a study conducted on asbestos insulation workers, the death rate from mesothelioma was 344 times higher than in the general population.
• Family members of asbestos workers have an increased risk of mesothelioma because asbestos dust is carried home on clothing.
• There is no association between mesothelioma and smoking.
• Mesotheliomas are primary tumors arising from the surface lining of the pleura, peritoneum, or pericardium. Pleural mesotheliomas are the most common form, comprising about 80% of the new cases.
• There are between 2,000 to 3,000 new cases of mesothelioma diagnosed in the United States every year and the incidence is increasing. The peak incidence of mesothelioma is expected to occur in this country in the year 2020.
• Men outnumber women by a 3:1 ratio.
• The mean age at onset of symptoms is about 60 years.
• The latent period between exposure and onset of symptoms ranges from 20 to 40 years.
• The Environmental Protection Agency banned all new uses of asbestos in 1989. However, uses established prior to 1989 are still allowed. Asbestos continues to be imported and used in the United States.
The stage of mesothelioma determines a patient’s treatment options. The most common type of staging system is the TNM system. The TNM staging system is based on three variables: the size and location of the tumor, the involvement of the lymph nodes, and metastasis. The TNM system is made up of four stages. In Stage I the lymph nodes are not involved and mesothelioma involves either the right or left pleura. In Stage II the lymph nodes are affected on the same side as the mesothelioma on the pleura and/or lung. In Stage III the lymph nodes may or may not be affected but the chest wall, heart, and other organs in the chest are affected by mesothelioma. And in the final stage, Stage IV, mesothelioma has spread throughout the chest and into most of the chest lymph nodes. Distant metastases are also included in this stage.
There are many types of treatments available for mesothelioma whether they are palliative or curative. Since symptoms do not usually present until twenty to fifty years following exposure to asbestos, patients tend to be in the severe stages following diagnosis. The treatment depends on the location of the cancer, how far the cancer has metastasized, and the patient’s age. The approximate survival rate for people diagnosed with mesothelioma is eight to twelve months. The survival rate may increase for those patients that are diagnosed in the early stages of the disease.
The three types of treatments used for mesothelioma are surgery, chemotherapy, and radiation. Surgery may be used to remove the malignancy. Chemotherapy is introduced to the body by intravenous chemicals in order to destroy the multiplication of malignant cells. Chemotherapy is also often used following the surgical removal of a tumor to make sure that all malignant cells are destroyed. Radiation can be used to help control metastases of the tumor or shrink the size of a tumor prior to surgical excision. Often combinations of the treatments prior mentioned are used together.
Mesothelioma may occur in men and women of any age. The most common risk factor is a history of asbestos exposure. As asbestos particle separate, they float in the air and may be inhaled or swallowed by a person. This is the main reason why the most common asbestos exposure causing mesothelioma is in the pleura. Smoking has not been proven to cause mesothelioma. However, if a person has a history of asbestos exposure it is very important to educate a person about cessation of smoking due to the increased risk of lung cancer. Today, the United States Occupational Safety and Health Administration (OSHA) have set limits for the acceptable levels of asbestos exposure. People that have occupations in which they may come in contact with asbestos are required to wear protective equipment to decrease their exposure levels.
Symptoms of early mesothelioma are very general and often ignored as a serious pathological process. Most patients do not have serious symptoms until two to three months prior to a mesothelioma diagnosis. Since the most common area affected are the lungs the most common symptoms tends to involve the respiratory tract. Symptoms of pleural mesothelioma may include: shortness of breath, cough, weakness, weight loss, and hoarseness.
The easiest type of test is a chest x-ray combined with a good history from the patient. The only difficulty with a chest x-ray is that it is not very specific in telling whether a process is malignant or benign. The most common sign on an x-ray is thickening of the lining of the lungs. CT scans are often the first test to reveal mesothelioma and its extent. The test that confirms the diagnosis of mesothelioma is a biopsy. A biopsy requires sample of tissue to be removed from the body and examined under microscope by a pathologist.
Mesothelioma is a type of cancer of the mesothelial cells in the membranes that line an organ. The most common area of mesothelioma is in the pleura (surrounding the lungs) but can include the peritoneum (surrounds organs in the abdomen). The most common cause associated with mesothelioma is asbestos exposure. Asbestos usage has decreased in the last fifteen to twenty years due to its link with causing malignancy. Asbestos is a generic term for a group of mineral silicates. Asbestos has great insulation properties but its fibers are easily spread through airborne. Asbestos was most commonly used in insulation products, which was directly used by some construction workers, factory workers, and miners. The risk of mesothelioma increases with increased exposure. Mesothelioma symptoms tend to show until twenty to fifty years following exposure. Though tobacco use can also be a cause of mesothelioma, it is has a stronger link to causing lung cancer.
The treatment options available for the management of mesothelioma are surgery, chemotherapy, and radiation.
- Surgery is reasonable when the disease is localized or confined within the pleura.
- The two surgical procedures used in the treatment of mesothelioma are pleurectomy with decortication and extrapleural pneumonectomy (thought to be the preferred method in managing early disease)
- Cisplatin is the drug of choice when mesothelioma is treated with chemotherapy.
- Doxirubicin is another agent that can be used when treating mesothelioma with chemotherapy.
- Radiation therapy has more of palliative effect and has no effect on survival.
- Another treatment option that can be used is the combination of surgery, chemotherapy, and radiation therapy.