All types of mesothelioma affect the mesothelium, which is a thin layer of tissue that surrounds most organs in the body. The pleura is the lining that surrounds the lungs, and when cancer begins here it is called pleural mesothelioma. The number one risk factor is exposure to asbestos. Most people diagnosed with pleural mesothelioma worked in an environment that exposed them to asbestos regularly. Other less common risk factors include genetics, a family history of pleural mesothelioma, and living with someone who worked around asbestos.
It may be the most common type of mesothelioma, but pleural mesothelioma is still rare. Only about 3,000 people are diagnosed with any type of mesothelioma each year. About 75 percent or more of those have the pleural form of the cancer. Most of these cases are seen in older men, reflecting the fact that workplace exposure to asbestos is the leading risk factor.
Asbestos and Pleural Mesothelioma
Asbestos was used extensively in construction and shipbuilding for many years and was only regulated beginning in the 1970s when health concerns came to light. Someone who inhaled fibers of asbestos on the job is at risk for pleural mesothelioma, yet only about five percent of these people will actually develop the disease.
The fibers of asbestos easily become airborne when not contained, and when inhaled they lodge in the lungs and pleura, causing damage. That damage can trigger illnesses like pleural effusion and asbestosis, and in some cases lung cancer or mesothelioma. The latency period, the time between initial asbestos exposure and diagnosis of mesothelioma is long, on average 30 to 40 years.
One reason that the diagnosis for most people with pleural mesothelioma only comes decades after exposure is because of thesymptoms. They don’t develop right away, and when they do, they mimic symptoms of other illnesses:
The most common symptoms of pleural mesothelioma are:
Shortness of Breath
Persistent Dry Cough
Coughing Up Blood
Pain When Breathing
Lumps Under the Skin of the Chest
The first difficulty in diagnosing mesothelioma is related to symptoms. The early symptoms too often cause a doctor to misdiagnose pleural mesothelioma as a less serious, lung related condition, like bronchitis or pneumonia. It may not be until after the symptoms persist and treatments have no effect that a patient will be tested further.
After a physical exam, the next step in diagnosing pleural mesothelioma is usually to do imaging scans. X-rays can usually rule out pneumonia, and can also pinpoint locations where tissues look abnormal. A CT or MRI can then look at those areas in better detail. From there a biopsy can be done on any suspected tumors.
A biopsy is a procedure that removes a small amount of tissue or fluid for examination. By looking at cells from the sample under a microscope a pathologist can determine if the cells are malignant. If they are malignant, or cancerous, the next step is to confirm that they are mesothelioma cells and not lung cancer cells. This last step can be tricky and may require an expert in pleural mesothelioma to make a final determination and diagnosis.
Staging and Treatment
Once a diagnosis of pleural mesothelioma has been given, the next step is to stage the cancer. This means looking at the original tumor, determining how far it has grown, and looking at how, if at all, the cancer has spread to other tissues outside the pleural lining. Pleural mesothelioma grows and metastasizes, or spreads, aggressively and quickly. It often spreads to the chest wall, the diaphragm, the lungs, and ultimately to the lymph nodes. From there it can spread even further. The more the original tumor has grown and the more the cancer has spread, the higher the staging will be.
When a medical team knows what the stage of the cancer is, they can develop an appropriate treatment planalong with the input of the patient. Treatment for pleural mesothelioma is typically aggressive and may include a combination of chemotherapy, radiation therapy, and surgery. Removal of an entire lung is one possibility for later stages of the cancer.
Because mesothelioma is rare and aggressive, clinical trials are possible for treatment for many patients given this diagnosis. Clinical trials are studies of new medications and therapies that are not yet approved by the Food and Drug Administration. By the time a new medication reaches this point it has been tested on laboratory animals and is considered mostly safe. Patients with deadly types of cancer like pleural mesothelioma are often accepted into these trials, although the treatments are riskier than those that are already approved.
The outlook for a diagnosis of pleural mesothelioma depends on each individual, but is generally not very good. Diagnosis typically comes after the cancer has reached a later stage and this means it is difficult to treat and nearly impossible to cure. Survival rates for this type of cancer are very low. Individual factors that affect prognosis include age, the stage of the cancer, whether the patient smokes, extent of exposure to asbestos, and gender.
With such a poor prognosis for this diagnosis, most patients need to consider how treatment will make them more comfortable or extend their lives. Some patients choose aggressive treatment in the hopes living longer, while others want to feel more comfortable. If the disease is very advanced, palliative or hospice care may be the best option.
Pleural mesothelioma is a terrible diagnosis to receive. Too many people who develop this disease were exposed to asbestos without their knowledge or without realizing what the risks were. Workplace asbestos exposure has led to many instances of this otherwise rare disease. If you have been impacted by pleural mesothelioma because of workplace asbestos exposure, you may have legal recourse to seek compensation from your former employer or the manufacturer of asbestos-containing materials.