What is Asbestosis ?

Asbestosis is a scarring of lung tissue caused by the inhalation of asbestos fibers. A portion of the fibers reach the alveoli (air sacs) where oxygen is transferred into the blood. Asbestos activates the lung's immune system and starts a reaction best described as an inflammatory process. Scavenger white blood cells (macrophages) try to break down the asbestos (phagocytosis) but are not successful, causing other cells (fibroblasts) to grow and form connective-tissue-based scars.

The formation of scar tissue or collagen in the lungs is known as fibrosis. The scar tissue slowly builds up, often reducing the lung's ability to deliver oxygen to the blood and remove carbon dioxide (reduced diffusion capacity). The total lung capacity or TLC may also be reduced. In severe cases, the impairment of lung function can strain the heart, or even result in heart disease, such as right-sided heart failure or "cor pulmonale."

Asbestosis and the Inflammatory Process

The inflammatory process starts within hours or days after inhalation of asbestos and injury at the cellular level begins shortly thereafter. In people who develop asbestosis, the inflammatory process continues to progress, fueled by indestructible asbestos fibers, even after exposure to asbestos ceases.

This asbestosis inflammatory process may continue undetected for decades causing no pain or respiratory symptoms. In many people, the process eventually produces symptoms-breathing abnormalities and radiographic changes. Usually, the first symptoms are shortness of breath and a dry cough. These symptoms often precede abnormalities on chest x-ray or pulmonary function tests. The period between exposure and diagnosis is called "latency" and may range from 10 to 50 years.

Where Is It Found?

More that 3,000 products in use today contain asbestos. Most of these are materials used in heat and acoustic insulation, fireproofing, and roofing and flooring. Some of the more common products that may contain asbestos include:

	Pipe and duct insulation.		Pot holders and ironing board pads.
	Building insulation.		Hairdryers.
	Wall and ceiling panels.		Floor tiles.
	Carpet underlays		Electrical wires.
	Roofing materials.		Textured paints.
	Artificial fireplaces and materials.		Cements.
	Patching and spackling compounds.		Toasters and other household appliances.
	Brake pads and linings.		Furnaces and other furnace door gaskets.

Asbestos is a group of silicate fibers with a crystalline structure. These naturally occurring fibers have been mined and used for about the last 100 years with peak use in the 1970's. At that time adverse health effects were widely associated with the use of asbestos. Although asbestos use has drastically declined in the United States, it continues to be used in developing countries. Of importance is the fact that the negative health effects associated with asbestos may take years to develop. Thus, workers exposed years ago and even people within close contact of workers (family members who may inhale asbestos fibers from worker's clothing) may begin to encounter the symptoms of asbestos-related disease today.

Asbestos is a serious threat to one's health because it can cause severe forms of lung disease. One form of disease and the topic of this pamphlet is asbestosis. Asbestosis is a fibrosis or scarring of the lung tissue. The lung is made of a delicate tissue which allows the blood to pick up oxygen and drop off carbon dioxide. As can be imagined, scarring of the lung tissue decreases the ability of the lung to exchange these gases. Second, one's chances of developing a tumor or cancer of the lung is five times greater than normal if exposed to asbestos. If the lung is also subjected to the deleterious effects of smoking on top of the asbestos exposure, one's chance of developing cancer is about 55 times greater than normal.

Incidence and Cause

When people inhale air, it always contains small particles.
These particles have to be filtered out because the lungs need to remain sterile. The nose and the bronchi (the airways leading down to the lungs) are the main air filters for the lungs. Asbestos particles (called amphiboles) are long, extremely thin, microscopic glass-like fibers that are not filtered by the nose or the bronchi because they are so thin and light. Asbestosis development starts when a person inhales an amphibole.

This particle travels deep into the lungs to one of the 300 million gas exchanging structures called an alveolus. Each alveolus has many cleaning cells called macrophages that eat up any particles that made it down to the alveoli. Unfortunately the macrophages can not eat the amphibole because it is too long, but they still try. In trying to eat this particle the macrophage essentially cuts itself open and the digestive molecules that were contained inside the macrophage have now spilled on the alveolus. These molecules injure the alveolus and cause it to form a scar.

This scarring formation is called fibrosis. The same amphibole that could not be eaten attracts other macrophages from neighboring areas. They try to eat the particle and also fail, and this further damages the lungs. In reality, people who are exposed to asbestos inhale hundreds and thousands of amphiboles, which causes large-scale injury. Such large-scale injury is when major lung damage (fibrosis) develops and is named "Asbestosis" after the disease-causing particle.

Asbestosis is found in people who are chronically exposed to asbestos material. Those who are at the highest risk are the people who directly handle asbestos material at their job. This group includes vehicle mechanics, construction workers, shipyard workers, electricians and other workers in the building trades. Of importance to workers in the United States is the fact that old asbestos can be encountered during refurbishing and demolition of old buildings or other structures in which asbestos is still found. Exposure to asbestos is not limited to those who directly handle the material.

The painter who works with the construction worker or the construction worker's wife who shakes out her husband's clothes have also been known to be at risk for developing asbestosis. A study conducted on Finnish asbestos workers who either worked construction for ten years or worked in shipyards for one year showed that 22% of the workers showed signs of asbestosis development. If one examines the entire population of a country instead of just those at high risk, Asbestosis is a relatively uncommon disease.

Signs and Symptoms

The signs and symptoms of asbestosis can show up many years after the asbestos exposure has ended. Manifestations rarely occur less than 10 years following first exposure and are more common after 20 years or more.

Symptoms (what a patient with asbestosis will experience)

• Shortness of breath.
• Asbestosis has been called a monosymptomatic disease because the earliest, most consistently reported, and most distressing symptom is shortness of breath.
• Occurs with heavy effort and then progressively diminishing levels of effort as the disease becomes worse.
• Persistent and productive cough.
• Almost as common as the shortness of breath.
• Often occurs with distressing spasms.

Other symptoms include:

• Chest tightness, Chest pain, General ill feeling, Fitful sleep, Hemoptysis, Appetite loss.

Signs (what your doctor will look for with asbestosis) :

• Basal crackles or rales. When a stethoscope is used to listen to the lower lungs , you can hear what sounds like Velcro opening up.
• An early distinctive feature of asbestosis.
• Usually heard first over the basal regions.
• Persistent (unaffected by coughing)
• Precise timing (at first, mid to late inspiration and eventually during most of inspiration)
• High pitched quality.
• Small irregular opacities on X-ray ( Looks like ground glass ).
• Obscures normal lung vasculature.
• Usually first seen in the lower lateral lobes in between the rib shadows.
• Borders of the heart, particularly the left side may be obscured.
• Pulmonary function tests usually show restrictive disease but can also show obstructive and mixed disorders. This means that your lungs will lose the ability to breathe .
• Reduced diffusion capacity.
• Reduce lung volumes and capacities
• Reduced flow rates.

• Clubbing of fingers and toes. Swelling of the fingers and toes due to excess blood accumulating there.

What are the Clinical Signs of Asbestosis?

Clinical presentation of this disease may include the following:

• Shortness of breath (dyspnea)
     -rarely occurs before a decade of exposure
     -appears first only upon exertion and subsequently occurs at rest
• Dry cough
     -dry and troublesome cough, perhaps associated with chest pain
• X-Ray changes
     -generally beginning with irregular opacities at the bases of the lungs,     perhaps extending into the upper zones gradually
• Pulmonary function deficiencies
     -typically a pulmonary function test reveals a restrictive lung disease     pattern
     -there may be a pulmonary function loss before x-ray changes     become evident

• Other more advanced symptoms of this disease include clubbing of the fingers (increased thickness of the digits and curvature of the nails) and cor pulmonale. Medical monitoring for radiologic changes is key, as persons with asbestosis have an increased risk of developing a malignancy

None of these symptoms are specific. Something as benign as the common cold could also give you these symptoms. Keep in mind that asbestosis is a chronic progressive disease meaning that once these symptoms start, they generally do not get better. Fortunately, the disease progresses slowly giving your doctor time to catch it.

Treatment and Prevention

Unfortunately, there currently is no cure for asbestosis. The treatment involves preventing further complications of the disease and treating its symptoms.

Prevention

A patient with asbestosis must first prevent any further contact with asbestos and if they are a smoker they should be advised to quit.

The asbestosis patient should receive aggressive medical care for any respiratory infection, with frequent use of antibiotics when warranted. Vaccinations for the flu and pnuemococcus should be kept up to date. They should also participate in respiratory therapies such as bronchial drainage or the use of an ultrasonic mist humidifier that assist in the clearing of secretions from the lungs. Patients should avoid situations that may expose them to respiratory infections such as large crowds. These steps should help to avoid the complications of serious lung infections. Finally, the asbestosis patient should undergo regular chest x-rays to screen for cancers associated with asbestosis.

Symptomatic Treatment

Shortness of breath is treated with bronchodilators that open up the bronchial tubes and allow passage of air. The patient may also receive supplemental oxygen. Respiratory treatments that remove secretions from the lung through postural drainage may also be used.

Productive cough is treated with humidifiers, breathing therapies and chest percussion. These therapies loosen and thin out bronchial secretions allowing them to be expelled by the cough. Chest pain can be treated with normal over the counter drugs such as acetaminophen or ibuprofen.

Prognosis

Once asbestosis has been established by findings on chest X-ray, regression of the disease is rare. The disease may remain unchanged, but it is generally slowly progressive due to accumulating damage caused by asbestos fibers in the lung. Rapid progression after the onset of symptoms is rare. Evidence of progression as seen on chest X-ray may require comparison of chest X-rays taken as many as 4-6 years apart.

There are several factors that determine progression, including the level and duration of exposure to asbestos, cumulative exposure, the type of asbestos fiber, and according to some studies, the status of the chest X-ray at the time of diagnosis. Progression will occur even in the absence of further exposure to asbestos, and it will likely be accelerated in the face of continued exposure.

As the disease progresses, the individual's shortness of breath becomes more pronounced. The shortness of breath initially experienced during heavy effort will be produced by lower levels of effort. It will eventually interfere with the ability to carry out everyday activities, and the individual may require oxygen. The end result of progression is failure of the lungs and eventual heart failure, resulting from the stress being placed on the heart.

Increased risk of infection may be a complication of asbestosis, although tuberculosis is uncommon. Individuals with asbestosis are at a considerably increased risk for developing lung cancer and other cancers associated with asbestos exposure, including mesothelioma and bronchogenic carcinoma.

There are certain measures a patient can take to slow the progression of the disease and prolong life. As mentioned previously, one way is to avoid further exposure to asbestos. Another thing is to stop smoking. Smoking may increase the rate of disease progression, and it definitely increases the risk of developing lung cancer.

Severe asbestosis is becoming a less common cause of death. More people are dying of other causes before their asbestosis progresses beyond the mild to moderate stage

Mesothelioma is a rare form of cancer in which malignant (cancerous) cells are found in the mesothelium, a protective sac that covers most of the body's internal organs. Most people who develop mesothelioma have worked on jobs where they inhaled asbestos particles.

What is the mesothelium?

The mesothelium is a membrane that covers and protects most of the internal organs of the body. It is composed of two layers of cells: One layer immediately surrounds the organ; the other forms a sac around it. The mesothelium produces a lubricating fluid that is released between these layers, allowing moving organs (such as the beating heart and the expanding and contracting lungs) to glide easily against adjacent structures.

The mesothelium has different names, depending on its location in the body. The peritoneum is the mesothelial tissue that covers most of the organs in the abdominal cavity. The pleura is the membrane that surrounds the lungs and lines the wall of the chest cavity. The pericardium covers and protects the heart. The mesothelial tissue surrounding the male internal reproductive organs is called the tunica vaginalis testis. The tunica serosa uteri covers the internal reproductive organs in women.

What is mesothelioma?

Mesothelioma (cancer of the mesothelium) is a disease in which cells of the mesothelium become abnormal and divide without control or order. They can invade and damage nearby tissues and organs. Cancer cells can also metastasize (spread) from their original site to other parts of the body. Most cases of mesothelioma begin in the pleura or peritoneum.

How common is mesothelioma?

Although reported incidence rates have increased in the past 20 years, mesothelioma is still a relatively rare cancer. About 2,000 new cases of mesothelioma are diagnosed in the United States each year. Mesothelioma occurs more often in men than in women and risk increases with age, but this disease can appear in either men or women at any age.

What are the risk factors for mesothelioma?

Working with asbestos is the major risk factor for mesothelioma. A history of asbestos exposure at work is reported in about 70 percent to 80 percent of all cases. However, mesothelioma has been reported in some individuals without any known exposure to asbestos.

Asbestos is the name of a group of minerals that occur naturally as masses of strong, flexible fibers that can be separated into thin threads and woven. Asbestos has been widely used in many industrial products, including cement, brake linings, roof shingles, flooring products, textiles, and insulation. If tiny asbestos particles float in the air, especially during the manufacturing process, they may be inhaled or swallowed, and can cause serious health problems. In addition to mesothelioma, exposure to asbestos increases the risk of lung cancer, asbestosis (a noncancerous, chronic lung ailment), and other cancers, such as those of the larynx and kidney.

Smoking does not appear to increase the risk of mesothelioma. However, the combination of smoking and asbestos exposure significantly increases a person's risk of developing cancer of the air passageways in the lung.

Who is at increased risk for developing mesothelioma?

Asbestos has been mined and used commercially since the late 1800s. Its use greatly increased during World War II. Since the early 1940s, millions of American workers have been exposed to asbestos dust. Initially, the risks associated with asbestos exposure were not known. However, an increased risk of developing mesothelioma was later found among shipyard workers, people who work in asbestos mines and mills, producers of asbestos products, workers in the heating and construction industries, and other tradespeople. Today, the U.S. Occupational Safety and Health Administration (OSHA) sets limits for acceptable levels of asbestos exposure in the workplace. People who work with asbestos wear personal protective equipment to lower their risk of exposure.

The risk of asbestos-related disease increases with heavier exposure to asbestos and longer exposure time. However, some individuals with only brief exposures have developed mesothelioma. On the other hand, not all workers who are heavily exposed develop asbestos-related diseases.

There is some evidence that family members and others living with asbestos workers have an increased risk of developing mesothelioma, and possibly other asbestos-related diseases. This risk may be the result of exposure to asbestos dust brought home on the clothing and hair of asbestos workers. To reduce the chance of exposing family members to asbestos fibers, asbestos workers are usually required to shower and change their clothing before leaving the workplace.

What are the symptoms of mesothelioma?

Symptoms of mesothelioma may not appear until 30 to 50 years after exposure to asbestos. Shortness of breath and pain in the chest due to an accumulation of fluid in the pleura are often symptoms of pleural mesothelioma. Symptoms of peritoneal mesothelioma include weight loss and abdominal pain and swelling due to a buildup of fluid in the abdomen. Other symptoms of peritoneal mesothelioma may include bowel obstruction, blood clotting abnormalities, anemia, and fever. If the cancer has spread beyond the mesothelium to other parts of the body, symptoms may include pain, trouble swallowing, or swelling of the neck or face.

These symptoms may be caused by mesothelioma or by other, less serious conditions. It is important to see a doctor about any of these symptoms. Only a doctor can make a diagnosis.

How is mesothelioma diagnosed?

Diagnosing mesothelioma is often difficult, because the symptoms are similar to those of a number of other conditions. Diagnosis begins with a review of the patient's medical history, including any history of asbestos exposure. A complete physical examination may be performed, including x-rays of the chest or abdomen and lung function tests. A CT (or CAT) scan or an MRI may also be useful. A CT scan is a series of detailed pictures of areas inside the body created by a computer linked to an x-ray machine. In an MRI, a powerful magnet linked to a computer is used to make detailed pictures of areas inside the body. These pictures are viewed on a monitor and can also be printed.

A biopsy is needed to confirm a diagnosis of mesothelioma. In a biopsy, a surgeon or a medical oncologist (a doctor who specializes in diagnosing and treating cancer) removes a sample of tissue for examination under a microscope by a pathologist. A biopsy may be done in different ways, depending on where the abnormal area is located. If the cancer is in the chest, the doctor may perform a thoracoscopy. In this procedure, the doctor makes a small cut through the chest wall and puts a thin, lighted tube called a thoracoscope into the chest between two ribs. Thoracoscopy allows the doctor to look inside the chest and obtain tissue samples. If the cancer is in the abdomen, the doctor may perform a peritoneoscopy. To obtain tissue for examination, the doctor makes a small opening in the abdomen and inserts a special instrument called a peritoneoscope into the abdominal cavity. If these procedures do not yield enough tissue, more extensive diagnostic surgery may be necessary.

If the diagnosis is mesothelioma, the doctor will want to learn the stage (or extent) of the disease. Staging involves more tests in a careful attempt to find out whether the cancer has spread and, if so, to which parts of the body. Knowing the stage of the disease helps the doctor plan treatment.

Mesothelioma is described as localized if the cancer is found only on the membrane surface where it originated. It is classified as advanced if it has spread beyond the original membrane surface to other parts of the body, such as the lymph nodes, lungs, chest wall, or abdominal organs.

How is mesothelioma treated?

Treatment for mesothelioma depends on the location of the cancer, the stage of the disease, and the patient's age and general health. Standard treatment options include surgery, radiation therapy, and chemotherapy. Sometimes, these treatments are combined.

Surgery is a common treatment for mesothelioma. The doctor may remove part of the lining of the chest or abdomen and some of the tissue around it. For cancer of the pleura (pleural mesothelioma), a lung may be removed in an operation called a pneumonectomy. Sometimes part of the diaphragm, the muscle below the lungs that helps with breathing, is also removed.

Radiation therapy, also called radiotherapy, involves the use of high-energy rays to kill cancer cells and shrink tumors. Radiation therapy affects the cancer cells only in the treated area. The radiation may come from a machine (external radiation) or from putting materials that produce radiation through thin plastic tubes into the area where the cancer cells are found (internal radiation therapy).

Chemotherapy is the use of anticancer drugs to kill cancer cells throughout the body. Most drugs used to treat mesothelioma are given by injection into a vein (intravenous, or IV). Doctors are also studying the effectiveness of putting chemotherapy directly into the chest or abdomen (intracavitary chemotherapy).

To relieve symptoms and control pain, the doctor may use a needle or a thin tube to drain fluid that has built up in the chest or abdomen. The procedure for removing fluid from the chest is called thoracentesis. Removal of fluid from the abdomen is called paracentesis. Drugs may be given through a tube in the chest to prevent more fluid from accumulating. Radiation therapy and surgery may also be helpful in relieving symptoms.

Are new treatments for mesothelioma being studied?

Yes. Because mesothelioma is very hard to control, the National Cancer Institute (NCI) is sponsoring clinical trials (research studies with people) that are designed to find new treatments and better ways to use current treatments. Before any new treatment can be recommended for general use, doctors conduct clinical trials to find out whether the treatment is safe for patients and effective against the disease. Participation in clinical trials is an important treatment option for many patients with mesothelioma.

People interested in taking part in a clinical trial should talk with their doctor. Information about clinical trials is available from the Cancer Information Service (CIS) (see below) at 1-800-4-CANCER. Information specialists at the CIS use PDQ®, NCI's cancer information database, to identify and provide detailed information about specific ongoing clinical trials. Patients also have the option of searching for clinical trials on their own. The clinical trials page on the NCI's Cancer.gov Web site, located at http://cancer.gov/clinical_trials on the Internet, provides general information about clinical trials and links to PDQ.

People considering clinical trials may be interested in the NCI booklet Taking Part in Clinical Trials: What Cancer Patients Need To Know. This booklet describes how research studies are carried out and explains their possible benefits and risks. The booklet is available by calling the CIS, or from the NCI Publications Locator Web site at http://cancer.gov/publications on the Internet.