Diseases of the pleura – the membranes lining the surface of the lungs and the inner surfaces of the chest cavity – are either benign or malignant. Benign diseases of the pleura are actually symptoms of other diseases; these are generally curable with the use of medication. Malignant pleural disease, i.e., mesothelioma(The most common form of which is pleural mesothelioma), is incurable and fatal. However, there are treatments available that can extend life and address the pain and discomfort associated with this type of cancer.
What the Pleura is and What It Does
Automobile service technicians recommend that engine oil be changed every six months; the purpose of this oil is to provide a thin film of lubricant between moving metal parts (i.e., the piston and the cylinder walls) in order to reduce the wear and tear of metal-on-metal contact.
Those who understand this have a good ideal of how the pleural lining works. It does essentially the same thing in the human body, providing a layer of lubrication between the lungs and the inner chest surfaces. Between the pleural lining of the outer lung surface (the visceral layer) and that of the inner chest wall (the parietal layer) is a narrow space called the pleural cavity. Normally, this space contains a small amount (less than 15 ml) of lymphatic fluid, which provides the lubrication.
When the pleura and/or lung is diseased or there are circulatory problems, this lining is affected. Lymphatic fluid can build up in the pleural cavity, as can air, blood or even pus, depending on the nature and location of the disease. The build-up of fluid is called pleural effusion. When the problem is a buildup of air in the pleural cavity, the condition is called pneumothorax.
Fibrous scar tissue can also build up on the pleural linings. This is common in cases of asbestosis.
In either case, the lungs’ ability to expand is severely compromised. The outside pressure on the lungs causes shortness of breath, coughs and chest pain.
What follows are the most common treatments currently used by medical professionals for the relief of pain and discomfort due to pleural diseaseand its symptoms.
Thoracentesis is also called a “pleural tap.” The purpose is to drain fluid or remove air that has accumulated in the pleural cavity. A special type of hollow needle, known as a cannula, is inserted into the pleural cavity. This needle is attached to a plastic tube, through which the air or fluid passes as it leaves the pleural cavity and drains into a bag or bottle.
This procedure can be completed as an outpatient procedure in as little as ten to twenty minutes, or may require two days in a hospital facility, depending on how much fluid must be removed from the pleural cavity.
For cases in which pleural effusion
Pleurodesis may be performed chemically or surgically. Chemical pleurodesis involves the introduction of bleomycin, tetracycline, iodine or talc slurry into the pleural cavity. These chemicals are injected by using the pleural tap in reverse.
This irritates the tissues of the pleural linings, causing them to fuse together. The procedure is often painful for the patient; sedatives and pain medication is usually necessary beforehand.
Surgical pleurodesis is the manual irritation of the outer (parietal) layer of the pleura using an abrasive pad. In extreme cases, the parietal layer of pleura is removed altogether.
Chemotherapy is the standard treatment for mesothelioma. Cancer is essentially the uncontrolled growth of bodily cells. Chemotherapeutic drugs attack cancerous cells by impairing their ability to divide and reproduce. Because the chemical treatments that destroy cancer cells also destroy healthy cells, the administration of chemotherapy must be precisely targeted at the malignancy. The destruction of some healthy tissue is inevitable, but by careful delivery, can be minimized.
Malignant mesothelioma, a form of asbestoscancer, generally does not respond to single drugs; usually, combinations of two or more are required in order to slow the progression of the disease. Most of the clinical trialcurrently underway involve new types of chemotherapeutic drugs.
Radiation treatment is a cancer treatment that uses high-energy radiation to directly target tumors and cancer cells. By specifically targeting tumors, cancer cells can be killed and therefore reduce the size of the tumor. radiation therapymay also be referred to as radiotherapy, brachytherapy or interstitial radiation depending on the type of radiation treatment.
This is difficult with mesothelioma, because the cancerous tissue spreads like a sheet rather than a lump. Some studies have suggested that the spread mesothelioma may be slowed by radiation therapy, but doses high enough to destroy the malignancy can also harm the lung tissue underneath as well as the heart, liver and spinal cord.
Photodynamic Therapy (PDT)
Photodynamic therapy is a fairly new treatment, currently available only at a few cancer specialty clinics around the nation. It is a non-invasive (non-surgical) procedure that targets malignant cells without harming healthy tissues.
The patient is administered a photo-reactive (light sensitive) drug that gathers in malignant tissues. Forty-eight hours later, the physician inserts a fiber-optic probe into the tumor. Finally, laser-generated beams of infrared light is delivered, which creates a photochemical reaction, destroying the cancerous tissue.
This therapy is most effective during the early stages of lung cancer. The only side effect noted among patients who have undergone PDT is an increased sensitivity to bright light and sun.
Patients for whom standard treatments have not been effective may benefit from participation in clinical trials. These are tests of cutting-edge treatments that have not yet been approved for general use; there are risks involved. On one hand, new treatments may be more effective. On the other hand, they may not work at all, there may be unexpected side effects, and costs associated with clinical trials will probably not be covered.