|
Authors: Dr Christopher W. Clarke MB, BS, PhD (Lond), FRACP, LLM is Honorary Medical Advisor Officer to adfa and a Consultant Thoracic Physician
What is asbestos?Asbestos is a mineral which has been mined extensively and processed for many commercial applications throughout the world. It is commonly known in its various forms as blue asbestos (crocidolite), brown asbestos (amosite), or white asbestos (chrysotile). How does asbestos get into the body?Asbestos fibres can become airborne because they are very fine. They can then be breathed into the lungs or swallowed. Swallowed fibres cause peritoneal (abdominal) mesothelioma. Is all asbestos harmful?All types of asbestos are unsafe for humans. The three forms of commercial asbestos that have been used in Australia are all harmful. There is no amount of asbestos exposure low enough to be guaranteed 100 per cent free of health risk. | ||||||||||||
|
Normally the chest wall pleura and the lung pleura have no space in between but they sit together because the lung fills up all the space inside the chest cavity. The lung structure resembles a tree. The air-ways form the trunk and branches and the air sacs (alveoli) are like the leaves. |
 |
 | ||||||||||
| ||||||||||||
|
Pleural plaques reach a certain size and then stop growing. They usually develop about 20 years after asbestos exposure started and they do not go away. They can be quite small but they may be numerous enough to cover most of the inside of the chest wall. |
 |
The risk for other asbestos related diseases is due to the asbestos exposure itself and not because pleural plaques have formed. A worker with plaques is no more likely to get an asbestos related disease than a workmate who had the same amount of asbestos exposure but did not have plaques.
What is benign Asbestos Related Pleural Disease (ARPD)?
ARPD usually begins with an inflammation of the pleura leading to fluid collecting in the space between the lung and the chest wall. This may be associated with some discomfort, but most usually it causes shortness of breath, which may come on over days or weeks.
 |
|
What treatment is available for
Asbestos Related Pleural Disease (ARPD)?
Removal of the fluid is usually indicated and is usually followed by immediate relief of breathlessness. This is a small procedure done with local anesthetic and it may need to be repeated if the fluid gathers again.
The fluid eventually stops coming back if nothing is done and the lung pleura may begin to thicken. This pleural thickening can be seen on x-ray or CT scan. Because the thickening of the pleura tends to squeeze the lung it may cause shortness of breath.
The amount of thickening may vary from person to person.
What is lung cancer?
|
Lung cancer is a lump of abnormal tissue in the lung. It is able to keep growing by using nutrients from the normal parts of the body. |
|
What has lung cancer got to do with asbetos?
Lung cancer is rare in people who do not smoke and who have not been exposed to asbestos. Lung cancer is still quite rare in asbestos workers who have not smoked but have been exposed to asbestos.
Asbestos workers who do smoke greatly increase their risk of lung cancer. This risk can be very high in heavy smokers who have also been exposed to ashestos.
The exposure needs to he sufficient to cause asbestosis although that may not be obvious.
If I stop smoking will it reduce my risk of lung cancer?
Yes!
The risk of lung cancer increases as the amount of smoking increases. Stopping smoking begins to reduce the risk of lung cancer. The greater benefit of stopping smoking is for those who have stopped smoking early. However, it is never too late to stop smoking and a reduced risk of lung cancer is to be expected.
What treatment is available for lung cancer?
Treatment is decided individually for each particular patient, but some general comments can be made.
The treatment for lung cancer in asbestos exposed workers is the same as for anyone with lung cancer. The earlier the diagnosis is made, the better the outcome of treatment.
Early lung cancer can sometimes be cured by surgery. If cancer has spread outside the lung. surgery would not usually be recommended as it would not cure the cancer.
One form of lung cancer (small cell lung cancer) is usually treated with chemotherapy (drug treatment) and not usually surgery because the results are better.
Radiotherapy is usually given to improve symptoms due to lung cancer.
What is Pleural Mesothelioma?
Mesothelioma is a malignant tumor, which develops in pleura.
|
The pleura is the wrapping tissue of the lung and also the lining tissue of the inside of the chest wall. It is a thin laver, normally transparent like plastic cling wrap. Mesothelioma tends to produce fluid which may compress the lung. It can be difficult to tell the difference between mesothelioma and benign asbestos related pleural disease without a tissue sample (biopsy). |
|
Mesothelioma continues to grow and never reaches a stable size. The effect it has on the body is like a weed in the garden; it can take over and interfere with normal body nutrition resulting in weight loss.
Mesothelioma usually occurs on one side of the chest affecting only one lung.
Mesothelioma takes many years to develop after first asbestos exposure. It rarely occurs before 15 to 20 years after first exposure and delays of 30 to 40 years are common.
What treatment is available for mesothelioma?
Unfortunately there is no cure for mesothelioma. There is research going on in Australia and overseas looking for new treatments.
There are procedures available to stop the repeated build-up of fluid due to mesothelioma in the pleural space. This reduces discomfort and repeated visits to hospital to remove fluid.
Treatment may be the injection of a chemical into the chest cavity (chemical pleurodesis), a small surgical procedure with a viewing instrument (thorascoscopy and pleurodesis), or a conventional surgical operation (thoracotomy and surgical pleurodesis).
These procedures are done to make life more comfortable, but they do not offer any prospect of permanent cure. Radiotherapy is now recommended to the site of a pleural aspiration in a patient with mesothelioma to prevent spread into the chest wall.
Newer chemotherapy agents are now available and patients should be given an opportunity to discuss them with an oncologist.
What is Peritoneal Mesothelioma?
Occasionally rnesotheliorna is not in the chest, but occurs in the abdomen. About one out of ten mesotheliomas is abdominal (or periotoneal).
The abdomen is lined with a similar type of tissue to the pleura, but it is called peritoneum when it is inside the abdominal cavity. The first sign of peritoneal mesothelioma is usually swelling of the abdomen.
In most cases peritoneal mesothelioma is associated with higher levels of asbestos exposure than pleural mesothelioma.
What is Asbestosis?
Asbestosis is a scarring disorder of lung tissue where in severe cases the spongy parts of the lung become stiffened and shrunken and the air sacs can neither hold as much air as normal nor transfer oxygen across to the body as effectively as usual.
|
The lung stiffness reduces the depth of each breath so breathing becomes faster and more shallow. Shortness of breath may become a problem. |
|
What treatment is available for Asbestosis?
The scarring process cannot be reversed by any known treatment.
Life can be made more comfortable by supportive treatment, such as oxygen supplied at home or portable oxygen systems for outings etc. for those with severe disease.
Respiratory rehabilitation programs may also help to improve general body fitness and performance while assisting breathless people to be more comfortable with their disability in this severe group.
How much asbestos exposure matters,
and when do the conditions present?
Any amount of asbestos exposure is too much.
Different asbestos diseases are due to different amounts of asbestos.
Asbestosis is definitely due to quite high doses of asbestos. The total amount of asbestos build-up in the body is what matters.
Asbestosis usually takes at least ten years to develop after first exposure.
Benign asbestos related pleural disease is caused by moderate levels of asbestos exposure but less than the levels usually required to cause asbestosis.
Pleural plaques usually require a moderate asbestos exposure, but occasionally plaques may be seen in what seems to have been fairly light exposure.
Lung cancer is linked to a significant amount of asbestos exposure, as well as the amount of smoking. It follows the same time course of asbestosis.
Mesothelioma may occur with very little asbestos exposure. Even owner/ renovators of fibro homes have developed mesothelioma, as have wives who regularly shook out asbestos workers' overalls before laundering.
It usually develops over a longer time lag from when originally exposed than original exposure to asbestos or pleural plaques does.
Smoking and asbestos
Smoking and asbestos exposure act together to multiply the number of lung cancer cases.
Stopping smoking does help to reduce this high lung cancer risk in asbestos workers.
Smoking also increases the risk of asbestosis, probably because it reduces the natural cleansing process of the lungs.
Asbestos workers will also suffer from the usual bad health effects from smoking (heart attack, stroke, poor circulation in the legs, chronic bronchitis and emphysema).
As far as we know, stopping smoking will not reduce the risk of mesothelioma or asbestos related pleural disease. However, lungs affected by smoking are likely to make the symptoms of these diseases worse because breathlessness will occur sooner in lungs which have already been damaged by smoking.
