Mesothelioma is a deadly cancer caused by asbestos -- a fluffy and hardy fiber once lauded for its fire- and heat-resistant properties. Decades ago, asbestos was so widely used it was common in everything from walls to clothing. But today, experts agree that asbestos is a dangerous substance that must be handled with caution.
While asbestos is not banned in the United States, there are many restrictions put on its use. Many other industrialized countries around the world have banned asbestos, including Australia, France and the United Kingdom. Asbestos is a name given to a group of minerals found in nature that look like petrified wood. When broken apart, this wood-like mass splinters into strands of fiber that are easily mixed or woven into other materials. Centuries ago, it was discovered that these fibers are nonconductive and resistant to harsh chemicals and other corrosives.
According to the U.S. Centers for Disease Control and Prevention, malignant mesothelioma is primarily caused by asbestos exposure. Even though the mineral is no longer mined in the U.S., it is imported. Also, a substantial amount of asbestos remains in aging structures. Each year, thousands of workers are unknowingly exposed.
Symptoms and Types of Mesothelioma
Mesothelioma is a disease that is known to have a long latency period, which means it takes a long time for the symptoms to appear. By that time, the disease is usually in the advanced stages. This latency period can take from 20 to 50 years, with about 30 years as the median time. In addition, family members of mesothelioma victims who are exposed to asbestos fibers have also been diagnosed with the disease as well.
Each year, up to 3,000 patients are diagnosed with the disease.
There are three main types of mesothelioma. The early symptoms for each type resemble pneumonia, including a persistent cough, shortness of breath and chest pains. For each type, there are accompanying symptoms that are exclusive to the area of the body where the disease originated:
Accounting for nearly 75 percent of all mesothelioma cases, pleural mesothelioma starts in the protective lining that surrounds the lungs called the pleura. It starts when an unsuspecting person breathes in asbestos fibers. The fibers become trapped in the lungs and migrate to the pleural membrane. These fine fibers irritate the tissue and cause scarring, which can eventually lead to cancerous tumors.
The initial symptoms of the pleural mesothelioma -- a persistent cough and chest pains -- are largely due to the accumulation of fluids in the chest cavity and the pleura. Other symptoms include:
- Painful breathing
- Chest pains
- Difficulty swallowing
- Coughing blood
- Shortness of breath
Because pleural mesothelioma is the most common of the mesothelioma diseases, it is known to have the most potentially curative treatment options.
This develops in the peritoneum, which is the lining that surrounds the abdomen. About 20 percent of all mesothelioma cases are peritoneal, accounting for up to 600 cases a year. Peritoneal mesothelioma starts when asbestos fibers are inhaled. The fibers then migrate from the lungs to the abdominal area. Doctors say the fibers migrate either through the lymphatic system or the digestive organs. Either way, these trapped fibers lead to changes in cells that cause cancerous tumors.
The initial symptoms of peritoneal mesothelioma include an accumulation of fluids in the abdomen, called ascites. Other symptoms appear after the disease is well established:
- Lumps under the skin the abdomen
- Diarrhea or constipation
- Night sweats
- Vomiting or nausea
- Unexplained weight loss
Treatment options include a peritonectomy, which is the surgical removal of the peritoneum, and cytoreductive surgery, which is aimed at removing tumors from multiple sites in the abdominal area.
As one of the rarest forms of mesothelioma, this develops on the pericardium or the lining that surrounds the heart. Pericardial mesothelioma accounts for about five percent of all mesothelioma cases. This disease results from the inhalation of asbestos fibers. When the fibers become lodged in the pericardium, they cause an irritation that can eventually lead to cancerous mesothelioma tumors.
The most common symptom of the disease is heart palpitations or an irregular heart beat, called an arrhythmia. Other symptoms also mimic heart conditions:
- Heart murmur
- Chest pains
- Difficulty breathing
- Night sweats
Because the disease process is located so close to the heart, there are limited options for treatment. Surgery is not typically an option, so many doctors opt for chemotherapy.
Doctors and New Treatment Methods
Medical professionals have long used standard treatments to attempt to eradicate all forms of mesothelioma. That includes chemotherapy, radiation and surgery, either separately or together. More recently, doctors started using multimodal therapies that combines two or more treatments with an aim at removing the tumors or controlling the disease process. Again, chemotherapy, radiation and surgery have been the therapies of choice for years. However, in recent years, doctors have been utilizing traditional treatments with newer ones that include the following:
Immunotherapy -- Also known as biotherapy, this utilizes the body’s immune system to treat mesothelioma. While this is still in the early, experimental stages, doctors see great promise. It can be administered in two ways -- using drugs to enhance the body’s current immune system or using man-made immune system proteins to make up for what is missing.
Gene Therapy -- Researchers are just beginning to understand how changes to DNA can help mesothelioma patients. Genes, which are part of our DNA, can control when and how our cells grow and divide. Gene therapy is aimed at controlling oncogenes, which cause an overgrowth of cells, and tumor suppressor genes, which slows cell division.
Photodynamic Therapy -- Also known as PDT, this uses a light-activated drug that is injected into a vein and collects on cancer cells. A special red light is placed inside the chest cavity and aimed at the cancerous cell clusters. This causes the cancer cells to die.
Improving Your Prognosis
Today, there are several factors that go into a positive prognosis, including early detection. However, that isn’t always possible. Because mesothelioma takes so long to manifest, it is typically not diagnosed until it is in the later and less-treatable stages. There are also a variety of factors that go into the overall prognosis:
- Type of mesothelioma
- Stage of mesothelioma
- Cell types
- Location of tumor
- Overall health
- Symptom progress
Many patients who have already been diagnosed with mesothelioma are urged to take part in clinical trials that may improve their recovery chances. Many clinical trials allow patients to be on the cutting edge of new research that may help the future of the disease.
At the same time, researchers have been working to develop technology that will allow for earlier detection, especially in those who have worked closely with asbestos or asbestos-laden products.
If you or a loved one has worked with asbestos or asbestos products, it is important to tell your doctor, even if you have no symptoms.
Agency for Toxic Substances & Disease Registry. Asbestos Health Effects. Retrieved from http://www.atsdr.cdc.gov/asbestos/asbestos/health_effects/
American Cancer Society. What’s new in malignant mesothelioma research and treatment? Retrieved from http://www.cancer.org/cancer/malignantmesothelioma/detailedguide/malignant-mesothelioma-new-research
American Lung Association. Mesothelioma Fact Sheet. Retrieved from http://www.lung.org/lung-disease/lung-cancer/resources/facts-figures/mesothelioma-fact-sheet.html
U.S. Centers for Disease Control and Prevention. Mesothelioma and the Environment. Retrieved from http://ephtracking.cdc.gov/showCancerMesotheliomaEnv.action