Diagnosis of Malignant Mesothelioma:

Diagnosis of Malignant Mesothelioma:


If there is a reason to suspect you may have mesothelioma, your doctor will use one or more methods to find out if the disease is present. The first step in diagnosing mesothelioma is recognizing your symptoms.

Signs and Symptoms of Mesothelioma

Early symptoms of mesotheliomas are not specific to the disease. People often ignore them or mistake them for common, minor ailments. Most people with mesothelioma have symptoms for only 2 to 3 months before they are diagnosed. About one-fourth of people have symptoms for at least 6 months before they are diagnosed.

Over half of patients with pleural mesothelioma have pain in the lower back or at the side of the chest. Many report shortness of breath. A smaller percentage have trouble swallowing, cough, fever, sweating, fatigue, and weight loss. Other symptoms include hoarseness, coughing up blood, swelling of the face and arms, muscle weakness, and sensory loss.

Symptoms of peritoneal mesothelioma include abdominal (belly) pain, weight loss, nausea, and vomiting. There may also be fluid or a mass in the abdomen.

If you have any of these symptoms and have been exposed to asbestos you should see a doctor right away

Imaging Tests

Chest x-ray: This may show irregular thickening of the pleura, calcium deposits on the pleura, or fluid in the pleural space. These findings suggest asbestos exposure leading to the development of a mesothelioma.

Imaging studies such as x-rays, computed tomography (CT) scans, and magnetic resonance imaging (MRI) scans will help determine the location, size, and extent of the cancer.

Computed tomography (CT): The CT scan is an X-ray procedure that produces detailed cross-sectional images of your body. Instead of taking one picture, like a conventional x-ray, a CT scanner takes many pictures as it rotates around you. A computer then combines these pictures into an image of a slice of your body. The machine will take pictures of multiple slices of the part of your body that is being studied.

CT scans are often used to make the initial diagnosis of malignant mesothelioma, and are helpful in staging the cancer (determining the extent of its spread).

Often after the first set of pictures is taken you will receive an intravenous injection of a "dye" or radiocontrast agent that helps better outline structures in your body. A second set of pictures is then taken.

CT scans are more tiring than regular x-rays because they take longer and you need to lie still on a table while they are being done. But just like other computerized devices, they are getting faster and your stay might be pleasantly short. Also, you might feel a bit confined by the ring you lie within when the pictures are being taken.

You will have an IV (intravenous) line through which the contrast "dye" is injected. The injection can also cause some flushing (redness and warm feeling). Some people are allergic and get hives or rarely more serious reactions like trouble breathing and low blood pressure. Be sure to tell the doctor if you have ever had a reaction to any contrast material used for x-rays. You may be asked to drink 1 to 2 pints of a solution of contrast material. This helps outline the intestine so that it is not mistaken for tumors.

Positron Emission Tomography (PET Scan): In this test, radioactive glucose (sugar) is injected into your vein. Because cancers use sugar much faster than normal tissues, the cancerous tissue takes up the radioactive material. A scanner can spot the radioactive deposits. This test, which is still being studied, is useful for telling whether a thickening of the tissues is cancer or merely scar tissue. It can also spot spread of the cancer.

Magnetic resonance imaging (MRI): MRI scans use radio waves and strong magnets instead of x-rays. The energy from the radio waves is absorbed and then released in a pattern formed by the type of tissue and by certain diseases. A computer translates the pattern of radio waves given off by the tissues into a very detailed image of parts of the body. Not only does this produce cross sectional slices of the body like a CT scanner, it can also produce slices that are parallel with the length of your body. A contrast material might be injected just as with CT scans, but is used less often. Sometimes MRI scans are useful in looking at the diaphragm (the thin muscle at the bottom of the lung cage that is responsible for breathing) where the mesothelioma may spread.

MRI scans are particularly helpful in examining the brain and spinal cord. MRI scans are a little more uncomfortable than CT scans. First, they take longer — often up to 1 hour. Also, you have to be placed inside a tube, which is confining and can upset people with claustrophobia (fear of enclosed places). The machine also makes a thumping noise that you may find disturbing. Some places will provide headphones with music to block this out.

Blood Tests

There are no blood tests that are useful in diagnosing malignant mesothelioma

Tests of fluid and tissue samples

If you have a pleural effusion (a build up of fluid) a sample of this fluid can be removed by inserting a needle into the chest cavity. A similar technique can be used to obtain abdominal fluid and pericardial fluid. The fluid is then tested to see its chemical make up and viewed under a microscope by an expert in diagnosing cancer (pathologist) to determine whether cancer cells are present.

A tissue sample of a pleural or pericardial tumor can be obtained using a relatively new technique called thoracoscopy. A thoracoscope (telescope-like instrument connected to a video camera) is inserted through a small incision into the chest. Your doctor can see the tumor through the thoracoscope, and can use special forceps to take a tissue biopsy. Similarly, laparoscopy can be used to see and obtain a biopsy of a peritoneal tumor. In this procedure, a flexible tube attached to a video camera is inserted into the abdominal cavity through small incisions on the front of the abdomen. Fluid can also be collected during thoracoscopy or laparoscopy. The biopsy specimen will be sent to the pathology laboratory where the pathologist will examine it to determine if it is cancer.

Surgery, either a thoracotomy (which opens the chest cavity) or a laparotomy (which opens the abdominal cavity), allows the surgeon to remove a larger sample of tumor or, sometimes, to remove the entire tumor.

If you might have pleural mesothelioma, the doctor may also do a bronchoscopy. In this procedure a flexible lighted tube is inserted through your mouth, down the trachea, and into the bronchi to see if there are other masses in the airway. Small samples of abnormal-appearing tissue can be removed for testing.

You may also have a mediastinoscopy. A lighted tube is inserted under the sternum (chest bone) at the level of the neck and moved down into the chest. Mediastinoscopy allows the surgeon to view the lymph nodes in this area and remove samples to check for cancer. Lymph nodes are bean-sized collections of immune system cells that help the body fight infections and cancers. Cancers in the lung often spread to lymph nodes, but mesotheliomas do this less often. Tests on lymph nodes can give the doctor information on whether a cancer is still localized or if it has started to spread, and can help distinguish lung cancer from mesothelioma.

It is often hard to diagnose mesothelioma by looking at the cells from the fluid around the lungs, abdomen, or heart. It is even hard to diagnose mesothelioma with tissue from small needle biopsies. Under the microscope, mesothelioma can look like several other types of cancer. For example, pleural mesothelioma may resemble some types of lung cancer and peritoneal mesothelioma may resemble some cancers of the ovaries. For this reason, special laboratory tests are often done to help distinguish mesothelioma from some other cancers.

These tests often use special techniques to recognize certain markers (types of chemicals) contained in mesotheliomas. One test called immunohistochemistry looks for different proteins on the surface of the cells. It can be used to tell if the cancer is a mesothelioma or a lung cancer, which can appear to start in the lining of the chest cavity. A newer test is called DNA Microarray analysis. This test actually looks at genes in the cancers. Mesotheliomas have different gene patterns than other cancers.

The electron microscope can sometimes help diagnose mesothelioma. This microscope can magnify samples more than 100 times greater than the light microscope that is generally used in cancer diagnosis. This more powerful microscope makes it possible to see the small parts of the cancer cells that distinguish mesothelioma from other types of cancer.
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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.

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What are the risk factors for mesothelioma?

The risk factors for mesothelioma

A risk factor is anything that increases your chance of getting a disease such as cancer. Different cancers have different risk factors. For example, exposing skin to strong sunlight is a risk factor for skin cancer. Smoking is a risk factor for cancers of the lung, mouth, larynx, bladder, kidney, and several other organs. Individuals exposed to asbestos should be encouraged to avoid tobacco exposure because together the risk for lung cancer is significantly higher than from smoking without a history of asbestos exposure. But having a risk factor, or even several, does not mean that you will get the disease.

Asbestos

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.

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.

Radiation

There have been a few published reports of pleural and peritoneal mesotheliomas that developed following exposure to thorium dioxide (Thorotrast). This material was used in the past by doctors for certain x-ray tests. Because Thorotrast was found to cause cancers, it has not been used for many years.

Zeolite

This is a silicate mineral, chemically related to asbestos, common in the soil of the Anatoli region of Turkey. Many cases of mesothelioma have been described in this region and may have been caused by this mineral.

Tobacco

Although tobacco smoking has not been associated with developing mesothelioma, the combination of smoking and asbestos exposure greatly increases the risk of lung cancer. Asbestos workers who also smoke have a lung cancer risk 50 to 90 times greater than that of the general population. More asbestos workers die of lung cancer than of mesothelioma.

SV40 Virus

Some recent studies have raised the possibility that infection with simian virus 40 (SV40) might increase the risk of developing mesothelioma. Some injectable polio vaccines prepared between 1955 and 1963 were contaminated with SV40. About 10 to 30 million people were probably exposed to the virus.

Intentional infection with SV40 of some laboratory animals, such as hamsters, causes mesotheliomas to develop. Researchers also have noticed that SV40 can cause mouse cells grown in dishes to become cancerous, and that asbestos increases the cancer-causing effect of SV40 on these cells. Other researchers have studied biopsy specimens of human mesotheliomas and detected SV40 DNA. However, similar fragments of SV40 DNA can also be found in noncancerous human tissues and some researchers think the SV40 viruses found are contaminants.

Another study did find SV40 virus in tissues from mesothelioma patients that did not appear to be contaminants. In this study, which also looked at tissue from healthy people, the SV40 virus wasn’t linked to mesothelioma unless the person was also exposed to asbestos. The researchers in this study thought the SV40 infection was not caused by the polio immunization, but occurred naturally as do other viral infections.

So far, the largest studies addressing this issue in humans have not found any increased risk for mesothelioma or other cancers among people who received the contaminated vaccines as children. But, the peak age range for diagnosis of mesothelioma is 50 to 70 years. Some researchers have pointed out that this issue may remain unresolved until more of the people accidentally exposed to SV40 between 1955 and 1963 reach that age range. Research into this important topic is still underway.

A recent study by the Institute of Medicine concluded that we still don’t know whether SV40 is responsible for some mesotheliomas and more research needs to be done. Last Revised: 10/19/2006

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How is Mesothelioma diagnosed?

A diagnosis of mesothelioma is most often obtained with careful assessment of clinical and radiological findings in addition to a confirming tissue biopsy. (Learn about typical mesothelioma symptoms.) A review of the patient's medical history, including history of asbestos exposure is taken, followed by a complete physical examination, x-rays of the chest or abdomen, and lung function tests. A CT scan or MRI may also be done at this time. If any of these preliminary tests prove suspicious for mesothelioma; a biopsy is necessary to confirm this diagnosis.

Is there a cure for Mesothelioma?

Unfortunately, the only current ways to combat Mesothelioma are heavy doses of Chemotherapy and medication. Depending on how advanced the cancer is, the treatment options vary.

Treatments for Mesothelioma

Research into new and more effective treatments for mesothelioma is ongoing. There is no cure as yet for mesothelioma. The standard treatments that attempt to hold back the progression of this cancer are:

• Surgery - to remove part of all of the affected body tissues
• Radiation therapy - to target and kill the mesothelioma cells
• Chemotherapy - the use of drugs, injected or taken orally, to kill or stop the growth of the cancer cells

How does mesothelioma kill you?

It will kill you like any other cancer- cancer cachexia, infections, etc

In addition it can compromise your respiratory functions (not enough lung tissue for your routine breathing)

If it involves major portion of lung that can add strain on your right heart which can fail(called cor pulmonale)

Mesothelioma :Over 2000 new patients from USA

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.