Early Info about mesothelioma, asbestosis, lung cancer and how to treatment, mesothelioma therapy, and mesothelioma prognosis, mesothelioma diagnosis, mesothelioma chemotherapy.
Note: smoking greatly increases risk - 50 to 90 times
The most common forms of asbestos disease are pleural plaques, asbestosis, lung cancer, and mesothelioma.
Asbestosis
Asbestosis is a disease which is characterized by pulmonary fibrosis, a progressive scarring of the lungs caused by the accumulation of asbestos fibers. Asbestosis is associated exclusively with chronic, occupational exposure. The build up of scar tissue interferes with oxygen uptake through the lungs and can lead to respiratory and heart failure. Often, asbestosis is a progressive disease, even in the absence of continued exposure. Symptoms include shortness of breath, cough, fatigue, and vague feelings of sickness. When the fibrosis worsens, shortness of breath occurs even at rest.
Pleural Plaques
Pleural plaques and pleural calcification are markers of exposure and may develop 10 to 20 years after initial exposure. Plaques are opaque patches visible on chest x-rays that consist of dense strands of connective tissue surrounded by cells. All commercial types of asbestos induce plaques. Plaques can occur even when fibrosis is absent and do not seem to reflect the severity of pulmonary disease.
Of all the diseases related to asbestos exposure, lung cancer has been responsible for over half of the excess deaths resulting from occupational exposure. Although tissues and cells react to the presence of asbestos immediately, detectable symptoms take years, or more often decades, to manifest themselves. Asbestos-induced lung cancer may not show up on x-rays for twenty years or more after the exposure began. This delay between exposure and onset is referred to as the "latency period". Even in cases of prolonged heavy exposure, abnormalities commonly appear on x-rays only after ten or more years following exposure.
Mesothelioma is rare or nonexistent in non-asbestos exposed populations but is becoming more common among asbestos-exposed individuals.
Mesothelioma is a cancer of the lining of the lungs and not a cancer that occurs inside the lung. Mesothelioma causes the cells of the mesothelium to become abnormal and infinitely reproduce.
A normal mesothelium cell (or any cell for that matter) can only reproduce a certain amount of times. This keeps certain cells from invading other cells. Cancer occurs when those cells become mutated and their limits are removed, allowing them to reproduce uncontrollably. These abnormal cells then form a lump that is known as a tumor. In a benign tumor the abnormal cells do not spread into surrounding areas, but malignant tumors do have the ability to spread. If the tumor is left untreated then it may spread and destroy the neighboring tissue. Sometimes cells can even break off the original tumor and spread to other organs and tissue through the bloodstream or the lympathic system. The lympathic system is part of the immune system. It is a complex system that includes the bone marrow, the thymus and the spleen, and lymph nodes throughout the body that are connected by a network of lympathic vessels. When the cancer cells reach a new site they may continue to divide and form a new tumor, which is referred to as a secondary tumor or a metastasis.
Mesothelial cells line the chest cavity, the abdominal cavity, and the cavity around the heart. They also cover the outer surface of most internal organs. The tissue that is formed by these mesothelial cells is called mesothelium. Mesothelium helps protect the organs by producing a lubricating fluid that lets organs move around. This fluid makes it easier for the lungs to expand and move around inside the chest during breathing. The mesothelium in the chest is called the pleura and the mesothelium around the abdomen is known as the peritoneum. The mesothelium around the heart (or the pericardial cavity, a sac like space around the heart) is called the pericardium.
The asbestos disease mesothelioma has a long latency period, where it is present but not evident or active. The disease can lie dormant for ten to sixty years after being exposed to asbestos. Because of this, it is often hard to determine the cause of mesothelioma.
Asbestos is the common name for any variety of silicate materials that are fibrous in structure and are more resistant to acid and fire than other materials. It has two forms, serpentine and amphibole, and is made of impure magnesium silicate. Asbestos is used for thermal insulation, fire proofing, electrical insulation, building materials, brake linings and has been used in numerous industries.
There are six different minerals commercially available that can make up "asbestos exposure", including:
Of these differerence minerals, chrysotile and amosite are most often used.
Asbestos is a potent carcinogen, that is, a cancer-causing substance, and is a serious health hazard. It is the known cause of pleural plaques, asbestosis, mesothelioma, and causes cancers of the lung, esophagus, and colon. Diseases caused by asbestos have a long latency period, usually taking ten to forty years before showing any symptoms of the disease. This is especially apparent today, when people who worked with installing asbestos as insulation and other materials in the 1970s are just now coming to realize that they are developing cancer at alarming rates.
Asbestos Exposure in My Home
The U.S. Environmental Protection Agency provides information in its website about possible locations in the home where asbestos hazards may be found9:
1. Some roofing and siding shingles are made of asbestos cement. 2. Houses built between 1930 and 1950 may have asbestos as insulation. 3. Asbestos may be present in textured paint and patching compounds used on wall and ceiling joints. Their use was banned in 1977. 4. Artificial ashes and embers sold for use in gas-fired fireplaces may contain asbestos. 5. Older products such as stove-top pads may have some asbestos compounds. 6. Walls and floors around wood burning stoves may be protected with asbestos paper, millboard, or cement sheets. 7. Asbestos is found in some vinyl floor tiles and the backing on vinyl sheet flooring and adhesives. 8. Hot water and steam pipes in older houses may be coated with an asbestos material or covered with an asbestos blanket or tape. 9. Oil and coal furnaces and door gaskets may have asbestos insulation.
How might I be exposed to asbestos?
We are all exposed to low levels of asbestos in the air we breathe. These levels range from 0.00001 to 0.0001 fibers per milliliter of air and generally are highest in cities and industrial areas.
People working in industries that make or use asbestos products or who are involved in asbestos mining may be exposed to high levels of asbestos. People living near these industries may also be exposed to high levels of asbestos in air.
Asbestos fibers may be released into the air by the disturbance of asbestos-containing material during product use, demolition work, building or home maintenance, repair, and remodeling. In general, exposure may occur only when the asbestos-containing material is disturbed in some way to release particles and fibers into the air.
Drinking water may contain asbestos from natural sources or from asbestos-containing cement pipes. top
How can asbestos affect my health?
Asbestos mainly affects the lungs and the membrane that surrounds the lungs. Breathing high levels of asbestos fibers for a long time may result in scar-like tissue in the lungs and in the pleural membrane (lining) that surrounds the lung. This disease is called asbestosis and is usually found in workers exposed to asbestos, but not in the general public. People with asbestosis have difficulty breathing, often a cough, and in severe cases heart enlargement. Asbestosis is a serious disease and can eventually lead to disability and death.
Breathing lower levels of asbestos may result in changes called plaques in the pleural membranes. Pleural plaques can occur in workers and sometimes in people living in areas with high environmental levels of asbestos. Effects on breathing from pleural plaques alone are not usually serious, but higher exposure can lead to a thickening of the pleural membrane that may restrict breathing. top
The Department of Health and Human Services (DHHS), the World Health Organization (WHO), and the EPA have determined that asbestos is a human carcinogen.
It is known that breathing asbestos can increase the risk of cancer in people. There are two types of cancer caused by exposure to asbestos: lung cancer and mesothelioma.Mesothelioma is a cancer of the thin lining surrounding the lung (pleural membrane) or abdominal cavity (the peritoneum). Cancer from asbestos does not develop immediately, but shows up after a number of years. Studies of workers also suggest that breathing asbestos can increase chances of getting cancer in other parts of the body (stomach, intestines, esophagus, pancreas, and kidneys), but this is less certain. Early identification and treatment of any cancer can increase an individual's quality of life and survival.
Cigarette smoke and asbestos together significantly increase your chances of getting lung cancer. Therefore, if you have been exposed to asbestos you should stop smoking. This may be the most important action that you can take to improve your health and decrease your risk of cancer.
Is there a medical test to show whether I've been exposed to asbestos?
Low levels of asbestos fibers can be measured in urine, feces, mucus, or lung washings of the general public. Higher than average levels of asbestos fibers in tissue can confirm exposure but not determine whether you will experience any health effects.
A thorough history, physical exam, and diagnostic tests are needed to evaluate asbestos-related disease. Chest x-rays are the best screening tool to identify lung changes resulting from asbestos exposure. Lung function tests and CAT scans also assist in the diagnosis of asbestos-related disease.
References Agency for Toxic Substances and Disease Registry (ATSDR). 2001. Toxicological Profile for Asbestos. Update. Atlanta, GA: U.S. Department of Health and Human Services, Public Health Service.
Early detection and diagnosis ofmesotheliomaoffers you the best chance of effectively fighting the disease. More often than not, patients suffering from mesothelioma will be treated with chemotherapy. Chemotherapy works to attack cancer cells and prevents them from multiplying, however, the science has not bee perfected so healthy cells are often destroyed alongside the cancer cells. This problem is the cause of many of the unpleasant side effects of chemotherapy treatments.
Mesothelioma
Mesothelioma is a form of cancer that is almost always caused by previous exposure to asbestos. In this disease, malignant cells develop in the mesothelium, a protective lining that covers most of the body's internal organs. Most people who develop mesothelioma have worked on jobs where they inhaled asbestos particles, or have been exposed to high levels of asbestos fibers.
Lung Cancer is the leading cause of death for both men and women. According to the American Cancer Society (ACS), in 2007 there will be about 213,000 new cases of lung cancer, and approximately 160,000 deaths. Average five-year survival rates for patients diagnosed with lung cancer are less than 15%. Five year survival rates for patients with advanced stage IV lung cancer are only about 5%. The population at highest risk for lung cancer includes approximately 5 million men and women between the ages of 50 and 69 who are current or former smokers.
Mesothelioma and Lung Cancer Study’s Objective in Evaluating LDCT Screening
December 24, 2007 — According to a recent and promising study in The Oncologist, researchers found that LDCT may be helpful in detecting pleural abnormalities including the early diagnosis of malignant pleural mesothelioma. Researchers evaluated low dose computed tomography (LDCT), i.e., spiral or helical computed tomography, screening of those exposed to asbestos. LDCT proved more effective at early detection of lung cancer than a chest radiograph (x–ray).
The objective of the study was to create a nonrandomized trial to evaluate the feasibility of baseline and annual repeat screening using LDCT for the early diagnosis of lung cancer and malignant pleural mesothelioma in a population that had been exposed to asbestos. 1,045 volunteers, already enrolled in a surveillance program for asbestos–exposed workers and former workers, were recruited for the study. The volunteers, between the age of 40–75, had no history of prior cancer, or other severe, preexisting conditions and no chest CT scan in the last two years. Participants underwent a structured interview regarding their medical and occupational history, including their involvement with asbestos. Researchers determined that the median age was 58 years, with an average amount of time exposed to asbestos of 30 years. Most participants, sixty–six percent, had smoked for almost 20 years.
After participants were screened, blood samples were taken and they were given respiratory tests, a chest x–ray and an initial LDCT screening. All LDCT images were reviewed by two radiologists and their findings were individually recorded, discussed and documented. In many participants, LDCT revealed nodules on their lungs, round or oval–shaped lesions, both benign and malignant. The nodules were identified and classified into categories. Positive baseline results were defined as noncalcified nodules (enlarged nodules that may be malignant) and pleural thickening (a hardening of the lungs). Participants with positive findings received a high–resolution CT–scan and additional diagnostic tests. If the nodule was not benign, it was treated by a CT–guided biopsy and video–assisted thoracoscopic surgery, or by a bronchoscopy—a procedure that allows your doctor to look at your airway through a thin viewing instrument called a bronchoscope.
LDCT Screening Results—Will LDCT Be Helpful in Early Diagnosis of Mesothelioma?
Results of LDCT screening were:
834 noncalcified (benign) nodules were detected in 44% of the participants on an initial LDCT compared to 43 noncalcified nodules in 4% of participants by chest x–ray.
There were nine cases of lung cancer detected by LDCT and none by chest x–ray. Of the nine lung cancers detected, eight lung cancers were Stage I and one was Stage IIA. All were treated with potentially curative surgery.
In addition, one person had a thymic carcinoid detected by LDCT. There were 11 false positive results.” (The Oncologist, August 21, 2007).
It was determined that annual repeat LDCT screening could provide useful information on the natural history and significance of asbestos–related pleural abnormalities.”" Researchers concluded that LDCT significantly increases the likelihood of detecting small nodules, and thus lung cancer, at an earlier, more curable stage.”" (The Oncologist, August 21, 2007) LDCT was 19 times more likely to detect nodules than the x–ray, and none of the malignant nodules were detected by x–ray.
LDCT’s sensitivity for detecting lung cancer is four times greater than the sensitivity of an x–ray. (American Family Physician, March 15, 2005) The assumption is that a 5– to 10–mm nodule found by LDCT is more curable than a 2– to 3–cm lesion seen on chest radiographs. (American Journal of Respiratory and Critical Care Medicine, March, 2001) . It is reasonable to expect that novel insights into the significance of pleural abnormalities may emerge from novel imaging techniques with higher resolution capabilities than 5–mm collimation CT. (The Oncologist, August 21, 2007)"
Although no cases of mesothelioma were detected in this study using LDCT, a very high number of pleural abnormalities were detected. Imaging is crucial in the diagnosis of mesothelioma. X–rays of the pleura (lining of the lungs) are used to show lung abnormalities such as pleural effusions (excess fluid between the two membranes that envelops the lungs) and pleural thickening which are symptoms of mesothelioma. Further clinical trials are necessary to evaluate the possibilities of using LDCT to detect and diagnose mesothelioma." resource : Brayton Purcell LLP
Study of the Protein Osteopontin Produced Encouraging Results.
According to a recent article published in the December 2005 New England Journal of Medicine, a recent study of the protein osteopontin produced encouraging results. Comparing patients diagnosed with mesothelioma, patients exposed to asbestos but disease free and healthy control subjects, revealed clear differences in the patients with malignant disease. Although more research is needed to confirm the accuracy of this investigation, a strong correlation between osteopontin levels and mesothelioma was found.
A significantly higher concentration of osteopontin was detected in patients with diagnosed cases of mesothelioma compared to subjects with asbestos exposure. When compared, the levels of osteopontin were not significantly different in unexposed control subjects versus those subjects exposed to asbestos. Nearly 78% of mesothelioma patients showed elevated osteopontin levels. Levels were elevated in both patients with early stage disease (Stage I) and advanced disease. In over 85% of cases, osteopontin levels differentiated patients with mesothelioma versus benign lung conditions.
Definitive detection of mesothelioma in the earlier stages makes surgical removal of tumors possible before the disease has had a chance to spread. Once spread occurs, the effectiveness of surgical treatment drops dramatically. In end?stage disease, surgery is simply a palliative measure to improve breathing capability with little of no curative value.
While it is not clear that this information will lead to longer survival, we do know that the earlier treatment can begin, the better chance for a prolonged life expectancy and with time, hopefully a cure. ( Mesothelioma Web).
Osteopontin is a type of protein that is involved in communication between cells, including signaling involved in the development of cancer. Osteopontin has also been linked to processes involved in cancer progression and spread. Furthermore, it can be found in circulating blood and would therefore be easily measured in individuals at a high risk of developing specific types of cancer.
In order to evaluate osteopontin as a potential marker for mesothelioma, researchers from several institutions conducted a clinical study to compare osteopontin levels in patients diagnosed with mesothelioma and patients with benign (non-cancerous) lung conditions. This study included 76 patients who had been diagnosed with mesothelioma, 69 individuals who had asbestos-related benign lung conditions and 45 healthy individuals who had not been exposed to asbestos. All individuals had their blood drawn and tested for osteopontin levels.
Overall, osteopontin levels were strongly associated with mesothelioma:
* Osteopontin levels were significantly higher in the group of patients diagnosed with mesothelioma compared to those individuals with asbestos-related lung complications (133 ng/ml versus 30 ng/ml, respectively).
* Osteopontin levels were not significantly different between individuals with asbestos-related lung conditions and those who were never exposed to asbestos.
* Osteopontin levels correctly identified nearly 78% of patients with mesothelioma, and accurately distinguished between mesothelioma and benign lung conditions at a rate of 85.5%.
* Osteopontin could accurately identify individuals with stage I mesothelioma (earliest stage - prior to spread), as well as those with advanced disease.
The researchers concluded that osteopontin may be a promising marker for the detection of mesothelioma. Furthermore, osteopontin identified patients with early-stagemesothelioma, a stage at which surgical removal is possible. However, further studies are necessary to confirm these findings, as well as determine whether early detection through osteopontin can improve survival.
Patients who have been exposed to asbestos may wish to speak with their physician regarding the risks and benefits of osteopontin testing or the participation in a clinical trial further evaluating screening measures for this disease. Two sources of information regarding clinical trials include the National Cancer Institute (cancer.gov) and www.cancerconsultants.com
Reference: Pass HI, Lott D, Lonardo F, et al. Asbestos exposure, pleural mesothelioma, and serum osteopontin levels. New England Journal of Medicine. 2005;353:1564-1573.
