What is Mesothelioma?
- Mesothelioma – General Information
- NEW Developments in Diagnosis
- Risk Factors
- Other Asbestos Related Cancer
Mesothelioma cancer, or malignant mesothelioma, is an extremely rare disease generally affecting the lining of the lungs, and, more rarely, the abdominal cavity and/or the heart. Mesothelioma cancer is most strongly associated with exposure to asbestos, and can remain latent in those exposed for 30 to 40 years.
There are three types of mesothelioma cancer: pleural, in which the cancer affects the lining of the lungs/chest; peritoneal, which affects the lining of the abdominal cavity; and pericardial, which affects the lining of the heart.
Pleural mesothelioma is the most common form of malignant mesothelioma, accounting for approximately three out of every four cases. The pleura is defined as the outer lining of the lungs and chest cavity. Pleural mesothelioma typcially has a latency period of 30-40 years or longer.
Peritoneal mesothelioma generally accounts for about 25 percent of maglignant mesothelioma cases diagnosed each year. It can have a shorter latency period than pleural mesothelioma, developing in 20-30 years or shorter. It affects the peritoneum, which is the lining of the abdominal cavity. Peritoneal mesothelioma generally occurs more often in males than females.
Pericardial mesothelioma, which affects the pericardium, the lining of the heart, is extremely rare. This form of malignant mesothelioma is usually fatal, due to its difficulty in diagnosis and treatment. It is generally diagnosed in a very late stage, and surgical or other treatment options are dangerous and difficult.
Mesothelioma in general is fairly rare in the United States. There are an estimated 2,000 to 3,000 new cases of mesothelioma each year in the United States. However, in European countries, especially the UK, as well as in Australia, the rate of mesothelioma is increasing.
For years, mesothelioma was thought to be rare in people under age 55. Traditionally seen primarily in older men, usually with a background of working in a factory, shipyard, mine or other environment with heavy asbestos exposure, today more and more cases of secondary exposure are being diagnosed, and it is affecting greater number of women.
The average age for someone with mesothelioma used to be around 72, but each year it seems mesothelioma affects younger people, and a greater number of women. Last year, a 3-year-old girl was diagnosed with mesothelioma, stunning the physicians who were treating her.
Mesothelioma is a serious disease. By the time the symptoms appear and cancer is diagnosed, the disease is often advanced. The average survival time is about 1 year. The 5-year relative survival rate is around 10%, but this rate has been slowly improving.
The 5-year survival rate refers to the percentage of patients who live at least 5 years after their cancer is diagnosed. Many of these patients live much longer than 5 years after diagnosis, and 5-year rates are used to produce a standard way of discussing prognosis.
Five-year relative survival rates do not include patients dying of other diseases and are considered to be a more accurate way to describe the prognosis for patients with a particular type and stage of cancer. That means that relative survival only talks about deaths from mesothelioma. Of course, 5-year survival rates are based on patients diagnosed and initially treated more than 5 years ago. They may no longer be accurate. Improvements in treatment result in a more favorable outlook for recently diagnosed patients.
Symptoms of Mesothelioma
Early symptoms of mesothelioma can be very general. Thus, they are often ignored.
Symptoms of pleural mesothelioma (lining of the chest) can include:
* pain in the lower back or at the side of the chest
* shortness of breath
* trouble swallowing
* weight loss
* swelling of the face and arms
* muscle weakness
Symptoms of peritoneal mesothelioma (lining of the abdominal cavity) include:
* belly pain
* weight loss
* fluid or a lump in the abdomen
Symptoms of pericardial mesothelioma (lining of the heart) include:
* constrictive pericarditis
* pericardial effusion
* cardiac tamponade
* heart failure caused by myocardial infarction
Of course, these same symptoms can also be caused by other minor ailments. But if you have worked with asbestos and you have any of these symptoms, you should see your doctor right away.
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. As a rule, a chest x-ray is not useful in finding mesothelioma early.
One test being studied is a blood test. This test measures the levels in the blood of a certain protein that is higher in people who have lung damage due to asbestos. It is even higher if the person has mesothelioma.
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.
New developments in Diagnosis of Mesothelioma
A recently published report in the Journal of the American Medical Association holds out hope for earlier detection of mesothelioma, a deadly cancer linked to asbestos exposure.
Researchers compared three types of endoscopic collection for accuracy in detecting cancerous cells in the lymph nodes to determine their accuracy.
Typically, doctors use several different techniques to diagnose lung cancers, including mesothelioma. Those techniques include physical exams, chest X-rays, CT scans and surgical biopsies to examine the cells in the lungs and the lymph nodes.
Lung cancer is one of the most common cancers worldwide, and the outcomes are typically unpromising. The low survival rates for lung cancer are often attributed to the difficulty of diagnosing the disease early enough for effective treatment.
This is especially true of mesothelioma, a disease that affects the tissues of the lining between the chest wall and the lungs. Often, by the time mesothelioma is detected, the cancer has reached untreatable stages.
Because of this, researchers are increasingly turning to new methods of detection that may identify deadly cancers at earlier stages when chemotherapy, surgery and other treatments may be effective.
The most accurate methods of diagnosis to date involve collecting cell samples from the lungs or lymph nodes for examination under a microscope. The most common method for collecting these cells is a mediastinoscopy, which is an invasive surgery that involves anesthesia and incision. The surgeon makes an incision at the top of the breast bone and inserts a thin, lighted tube into the chest cavity to withdraw cell and fluid samples.
Mediatinoscopy is typically used to determine whether fluids in the chest cavity contain cancerous cells or asbestos fibers.
In the past few years, doctors have developed less invasive procedures to collect tissue samples from the chest. These procedures use an endoscope, a small medical device that consists of a camera mounted on a flexible tube. Ultrasound probes, needles and other instruments can be inserted through the tube to remove samples for biopsy. These endoscopic procedures are far less invasive than more traditional methods, reducing the risks to patients who undergo them.
In the study reported in JAMA, researchers compared three different procedures using an endoscope, each of them considered minimally invasive:
- Transbronchial needle aspiration (TBNA)
- Endobronchial ultra-sound guided fine needle aspiration (EBUS-FNA)
- Transesophegeal endoscopic ultrasound-guided fine needle biopsy (EUS-FNA)
In each procedure, an endoscope was used to remove tissues or fluids with a fine needle. The researchers then compared the findings among the three methods to determine which was the most sensitive for detecting the presence of cancerous cells in the lymph nodes of the chest.
The study consisted of tests taken on 138 patients in the U.S. who were believed to have lung cancer. Each patient underwent all three procedures in sequence.
The results of the study showed:
- 30% (42) of the patients had malignant lymph nodes
- EBUS-FNA detected 29 of the cancers. TBNA only detected 15
- EUS-FNA and EBUS-FNA used in combination detected 93% of the cancers.
The combination was also able to detect malignancies in patients who would not have been identified by CT scans of the chest. The results of the study suggest that the minimally invasive procedures may be a viable alternative to more invasive standard procedures for evaluation patients believed to have lung cancer.
The lower risks associated with the procedure will make the diagnostic process more comfortable for patients and provide for a shorter recovery time.
Reference: Wallace, M, Pascual, J, Raimondo, M, et al. Minimally invasive endoscopic staging of suspected lung cancer. Journal of American Medical Association. 2008. 299(5) 540-546. Source: www.asbestos.com
New System May Give Lung Cancer Patients Hope
The Associated Press Aug. 31, 2007 http://www.msnbc.msn.com/id/20533486
Thousands more lung cancer patients each year could be offered surgery or other aggressive therapy under a new system that classifies many tumors as more treatable than in the past.
It is the first big overhaul of a decades-old method used to predict survival and help determine whether a lung cancer patient will have surgery, chemotherapy or be treated at all.
The new guidance is to be presented at a conference of lung cancer specialists in Seoul, South Korea, that starts Saturday. It is expected to be adopted by policy-making groups in the next year. Lung cancer is the world’s top cancer killer, claiming 1.3 million lives each year.
In the United States, 213,380 new cases and 160,390 deaths from the disease are expected this year. Nearly 60 percent of people die within one year of diagnosis, and nearly 75 percent die within two years, American Cancer Society statistics show.
In treating it, doctors use a formula called tumor staging. It is based on a tumor’s size, how far it has spread and other factors to predict a patient’s survival odds and to guide treatment.
More precise sorting
The current system was developed from about 5,000 tumor samples from University of Texas M.D. Anderson Cancer Center in Houston decades ago — before improved scanning technology was available to evaluate a cancer’s spread.
The new plan is based on 100,000 tumor samples from around the world including Asia, where lung cancer rates are projected to climb because of trends in smoking, unhealthy lifestyles and aging populations. It keeps four broad groupings but sorts people more precisely based on refined understanding of tumor characteristics.
The result: “There will clearly be shifting of patients from categories not operable to operable” — as many as 10,000 a year in the United States, said Dr. David Johnson, a lung cancer specialist at Vanderbilt University in Nashville, Tenn. He reviewed the plan, which was partly published in a medical journal recently.
The stage of the tumor at diagnosis is the best predictor of survival. Only 20 percent of cases are diagnosed in Stages 1 or 2, when tumors are small and confined to a lung, Johnson said. About 30 percent to 40 percent are found in Stage 4, after they have widely spread. The rest are in the middle.
Five-year survival rates are 47 percent for Stage 1 and 26 percent for Stage 2, but only 8 percent for Stage 3, and 2 percent for Stage 4, according to the American College of Surgeons.
Most lung cancers are the type called ”non-small cell,“ which is covered by the new staging system. The system was developed by the International Association for the Study of Lung Cancer, a group of lung cancer specialists from around the world.
Dr. Peter Goldstraw, a surgeon at the Royal Brompton Hospital in London, led the project, and Canadian scientists independently validated the recommended changes by comparing survival across geographic regions.
Among the changes: creating more sub-stages for tumor size, reassigning some large tumors to a more advanced stage, reclassifying tumors that have spread into the fluid surrounding the lung, and recognizing that spread to certain lymph nodes is more dangerous than its spread to others.
“By changing some of these groupings, some patients will get moved to an earlier stage of disease for which we tend to be more aggressive” in treatment, said Dr. Joan Schiller, a lung cancer specialist at the University of Texas Southwestern Medical Center in Dallas .
“Before, a patient may have only been offered chemotherapy. They may now be offered chemotherapy and radiation,” or more intense radiation, she said. Conversely, some people thought to have earlier-stage tumors now will be grouped with those whose tumors have widely spread, and discouraged from undergoing therapies that have little chance of helping them.
“In some cases, patients were getting inappropriately aggressive treatment,” Schiller said.
Some people with very small tumors may get away with less therapy — taking out just a segment of lung instead of an entire lobe, said Dr. Stephen Swisher, a chest surgeon at M.D. Anderson.
The impact of the changes in Europe and Japan is unclear because doctors in those countries tend to remove whole lungs rather than lobes to treat lung cancer, Johnson noted. Doctors hope that ultimately survival will improve, but that won’t happen “unless we get patients into the right hands” and they get correct treatment, Johnson said.
Revising the staging system also will do little good if doctors don’t do the right tests to properly stage a tumor, said Dr. Len Lichtenfeld, deputy chief medical officer of the American Cancer Society. Staging for lung and other types of cancer should become even more precise in the near future as biomarkers and gene tests are developed to better sort patients, he added.
© 2007 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.
Risk Factors for Mesothelioma
The main risk factor for developing mesothelioma is exposure to asbestos.
Asbestos refers to a family of fibrous minerals made of silicate. Asbestos was once used in many products such as insulation, floor tiles, door gaskets, soundproofing, roofing, patching compounds, fireproof gloves and ironing board covers, and even brake pads.
As the link between asbestos and mesothelioma has become well known, the use of this material has almost stopped. Most use stopped after 1989, but it is still used in some products. Experts have linked this drop in asbestos use to the fact that the rate of development of mesothelioma is no longer increasing [in the U.S.].
Still, up to 8 million Americans may already have been exposed to asbestos. Exposure to asbestos particles suspended in air and building materials is much less hazardous except when they are being removed.
Since asbestos is a naturally occurring mineral, it can also be found in dust and rocks in certain parts of the United States as well as the world.
According to the U.S. Environmental Protection Agency, as many as 733,000 schools and public buildings in the country today contain asbestos insulation. As many as 10% to 15% of schools in the United States may contain asbestos insulation.
People who may be at risk for occupational asbestos exposure include some miners, factory workers, insulation manufacturers, railroad workers, ship builders, gas mask manufacturers, and construction workers, particularly those involved with installing insulation.
Several studies have shown that family members of people exposed to asbestos at work have an increased risk of developing mesothelioma, because asbestos fibers are carried home on the clothes of the workers.
The incidence rate for mesothelioma in men is dropping, probably because they are no longer being exposed directly to asbestos in their work. But the incidence rate for mesothelioma in women is steady, which suggests that they are being exposed in a way that is not directly tied to work, but more to their environment either at home or work. One example would be asbestos in buildings where they work or live.
A study from California also links mesothelioma to naturally occurring asbestos deposits in mountains.
Another important point about asbestos and mesothelioma is that the risk of mesothelioma does not drop with time after exposure to asbestos. The risk appears to be lifelong and undiminished.
There are 2 main forms of asbestos — serpentine and amphiboles. Serpentine fibers are curly and pliable. Chrysotile is the only type of serpentine fiber and it is the most widely used form of asbestos. Amphiboles are thin, rod-like fibers. There are 5 main types — crocidolite, amosite, anthrophylite, tremolite, and actinolyte. Amphiboles (particularly crocidolite) are considered to be the most carcinogenic (cancer-causing).
However, even the more commonly used chrysotile fibers are associated with malignant (cancerous) mesotheliomas and should be considered dangerous as well.
When asbestos fibers are inhaled, most are cleared in the nose, throat, trachea (windpipe), or bronchi (large breathing tubes of the lungs). Fibers are cleared by sticking to mucus inside the air passages and being coughed up or swallowed. The long, thin, fibers are less readily cleared, and they may reach the ends of the small airways and penetrate into the pleural lining of the lung and chest wall. These fibers may then directly injure mesothelial cells of the pleura, and eventually cause mesothelioma.
Asbestos fibers can also damage cells of the lung and result in asbestosis (formation of scar tissue in the lung), and/or lung cancer.
The risk of lung cancer among people exposed to asbestos is increased by 7 times, compared with the general population. Indeed, asbestosis, mesothelioma, and lung cancer are the 3 most frequent causes of death and disease among people with heavy asbestos exposure.
Peritoneal mesothelioma, which forms in the abdomen, may result from coughing up and swallowing inhaled asbestos fibers. Cancers of the larynx, pancreas, esophagus, colon, and kidney may also come from asbestos exposure, but the increased risk is small.
The risk of developing a mesothelioma is related to how much asbestos a person was exposed to and how long this exposure lasted. People exposed at an early age, for a long period of time, and at higher levels are most likely to develop this cancer.
Mesotheliomas take a long time to develop. The time between first exposure to asbestos and diagnosis of mesothelioma is usually between 20 and 50 years.
Other Asbestos-Related Cancer
Asbestos Related Lung CancerLung cancer, or bronchial carcinoma, occurs in several forms. The most common causes of lung cancer are smoking and asbestos.
This web site has focused on the most lethal of the lung cancers – mesothelioma. Not every asbestos-related lung cancer, however, is a mesothelioma. Other thoracic carcinomas, such as adenocarcinoma, are also caused by exposure to asbestos.
The connection between asbestos exposure and lung cancer was noted as early as 1925, and confirmed over the next 70 years by many epidemiologic studies of asbestos-exposed workers.
The four main types of commercially used asbestos, chrysotile, amosite, anthophyllite, and mixtures containing crocidolite, have all been associated with an increased risk of lung cancer. About one in seven people who suffer from asbestosis, a lung disease resulting from high exposure to asbestos, eventually develop lung cancer.
Asbestos is estimated to account for 3,400 to 8,500 new lung cancer cases in the United States each year. Like mesothelioma, the latency period between asbestos exposure and the development of asbestos related lung cancer may be two, three, four, or even more decades.
Very often, asbestos-related cancer victims also suffer from asbestosis, a scarring of the lung tissue caused by asbestos exposure. About one in seven people with asbestosis will eventually develop lung cancer.
Although commonly associated with lung cancer, adenocarcinoma is a type of cancer that develops in cells lining glandular types of internal organs, such as the lungs, breasts, colon, prostate, stomach, pancreas, and cervix.
Another type of adenocarcinoma, mucinous adenocarcinoma, accounts for only 10-15% of all adenocarcinomas and is particular to aggressive carcinomas that are comprised of at least sixty percent mucus. Non-small cell lung cancers make up over three quarters of all new lung cancer cases in the United States.
While there is only one type of small cell lung cancer, there are three types of non-small cell lung cancer. The three types of non-small cell lung cancer are squamous carcinoma, large cell carcinoma, and adenocarcinoma. When adenocarcinoma develops in the lung’s air sacs, it is called bronchioalveolar adenocarcinoma. About forty percent of all lung cancer cases diagnosed today are adenocarcinoma.
The progression of adenocarcinoma is quite unpredictable. In most cases, adenocarcinoma spreads slowly and causes very few lung cancer symptoms. But it can also be extremely invasive, aggressively spreading through the body and causing death before it can be treated. Given the disease’s variability, the five-year prognosis for patients with adenocarcinoma is dim: most are given only a 10 percent chance of survival.
Sometimes, tumors spread to the liver, adrenal glands, and bones, making adenocarcinoma much more difficult to treat. Symptoms of adenocarcinoma lung cancer may include shortness of breath, the coughing up of blood, fatigue, chest pains, and unexplained weight loss. Adenocarcinoma is usually treated with surgery, radiation therapy, and chemotherapy.