There is always research going on in the area of mesothelioma. Scientists are looking for causes and ways to prevent mesothelioma. Doctors are working to improve accuracy of diagnosis and effectiveness of treatment. Despite recent progress, much remains to be learned about the best way to treat these cancers.

Causes and Prevention

Much of the research on mesothelioma has focused on learning exactly how asbestos changes mesothelial cells and their DNA to cause these cancers. Understanding how these fibers produce cancer might help us develop ways to prevent those changes.

The risk of asbestos in developing mesothelioma is a definite public health concern. We are continuously learning more about which fibers can produce cancer, how they cause these cancers, and what levels of exposure can be considered safe. Now that we know about the dangers of asbestos, we can limit or stop exposure in homes, public buildings, and the workplace. Unfortunately, regulations protecting workers from asbestos exposure are much less stringent in some countries and nonexistent in others.

Research is also underway to clarify the role (if any) of SV40, a virus that has been linked to mesothelioma in some studies.

New Drugs

Because chemotherapy drugs have not been very effective against advanced mesothelioma, several new approaches to cancer treatment are now being studied. These include anti-angiogenesis drugs (which kill cancers by stopping their blood supply) such as Bevacizumab (Avastin) and anti-growth factor drugs (which interfere with substances some cancer cells produce to stimulate their own growth) such as Erlotinib (Tarceva).

Multimodality Therapy

Doctors are always learning more about the best way to treat patients with mesotheliomas. The roles of surgery, radiation therapy, and chemotherapy in the treatment of mesothelioma are highly debated. Treatments that use some combinations of surgery, radiation therapy, and chemotherapy, called multimodality therapy, are now being studied and may provide the most promising option for some patients. New chemotherapy drugs are currently being tested in clinical trials, together with other types of treatment.

Ranpirnase (Onconase) is an enzyme that breaks down RNA and in preliminary studies has helped some patients with mesothelioma to live longer. Larger clinical trials are currently in progress. Another new drug being tested in mesothelioma clinical trials is suberoylanilide hydroxamic acid (vorinostat, [SAHA]), which may reduce growth of mesothelioma cells by inhibiting an enzyme that controls certain proteins called histones, which regulate DNA.

Gene Therapy

A new approach to cancer therapy being tested on mesothelioma is gene therapy. One of these approaches to treating mesothelioma uses special viruses that have been modified in the laboratory. The modified virus is injected into the pleural space and infects the mesothelioma cells. When this infection occurs, the virus injects a gene into the mesothelioma for interferon-beta, an immune system hormone (cytokine) that may help activate immune system cells to attack the cancer.

Completing treatment can be both stressful and exciting. You will be relieved to finish treatment, yet it is hard not to worry about cancer coming back. (When cancer returns, it is called recurrence.) This is a very common concern among those who have had cancer.

It may take a while before your confidence in your own recovery begins to feel real and your fears are somewhat relieved. Even with no recurrences, people who have had cancer learn to live with uncertainty.

Make Healthier Choices

Think about your life before you learned you had cancer. Were there things you did that might have made you less healthy? Maybe you drank too much alcohol, or ate more than you needed, or smoked, or didn’t exercise very often. Emotionally, maybe you kept your feelings bottled up, or maybe you let stressful situations go on too long.

Now is not the time to feel guilty or to blame yourself. However, you can start making changes today that can have positive effects for the rest of your life. Not only will you feel better but you will also be healthier. What better time than now to take advantage of the motivation you have as a result of going through a life-changing experience like having cancer?

You can start by working on those things that you feel most concerned about. Get help with those that are harder for you. For instance, if you are thinking about quitting smoking and need help, call the American Cancer Society’s Quitline® tobacco cessation program at 1800-ACS-2345.

Diet and Nutrition

Eating right can be a challenge for anyone, but it can get even tougher during and after cancer treatment. For instance, treatment often may change your sense of taste. Nausea can be a problem. You may lose your appetite for a while and lose weight when you don’t want to. On the other hand, some people gain weight even without eating more. This can be frustrating, too.

If you are losing weight or have taste problems during treatment, do the best you can with eating and remember that these problems usually improve over time. You may want to ask your cancer team for a referral to a dietitian, an expert in nutrition who can give you ideas on how to fight some of the side effects of your treatment. You may also find it helps to eat small portions every 2 to 3 hours until you feel better and can go back to a more normal schedule.

One of the best things you can do after treatment is to put healthy eating habits into place. You will be surprised at the long-term benefits of some simple changes, like increasing the variety of healthy foods you eat. Try to eat 5 or more servings of vegetables and fruits each day. Choose whole grain foods instead of white flour and sugars. Try to limit meats that are high in fat. Cut back on processed meats like hot dogs, bologna, and bacon. Get rid of them altogether if you can. If you drink alcohol, limit yourself to 1 or 2 drinks a day at the most. And don't forget to get some type of regular exercise. The combination of a good diet and regular exercise will help you maintain a healthy weight and keep you feeling more energetic.

Rest, Fatigue, Work, and Exercise

Fatigue is a very common symptom in people being treated for cancer. This is often not an ordinary type of tiredness but a “bone-weary” exhaustion that doesn’t get better with rest. For some, this fatigue lasts a long time after treatment, and can discourage them from physical activity.

However, exercise can actually help you reduce fatigue. Studies have shown that patients who follow an exercise program tailored to their personal needs feel physically and emotionally improved and can cope better.

If you are ill and need to be on bed rest during treatment, it is normal to expect your fitness, endurance, and muscle strength to decline some. Physical therapy can help you maintain strength and range of motion in your muscles, which can help fight fatigue and the sense of depression that sometimes comes with feeling so tired.

Any program of physical activity should fit your own situation. An older person who hasnever exercised will not be able to take on the same amount of exercise as a 20-year-old who plays tennis 3 times a week. If you haven’t exercised in a few years but can still get around, you may want to think about taking short walks.

Talk with your health care team before starting, and get their opinion about your exercise plans. Then, try to get an exercise buddy so that you’re not doing it alone. Having family or friends involved when starting a new exercise program can give you that extra boost of support to keep you going when the push just isn’t there.

If you are very tired, though, you will need to balance activity with rest. It is okay to rest when you need to. It is really hard for some people to allow themselves to do that when they are used to working all day or taking care of a household. (For more information about fatigue, please see the publication, "Cancer Related Fatigue and Anemia Treatment Guidelines for Patients.")

• Exercise can improve your physical and emotional health.

• It improves your cardiovascular (heart and circulation) fitness.

• It strengthens your muscles.

• It reduces fatigue.

• It lowers anxiety and depression.

• It makes you feel generally happier.

• It helps you feel better about yourself.

And long term, we know that exercise plays a role in preventing some cancers. The American Cancer Society, in its guidelines on physical activity for cancer prevention, recommends that adults take part in at least 1 physical activity for 30 minutes or more on 5 days or more of the week. Children and teens are encouraged to try for at least 60 minutes a day of energetic physical activity on at least 5 days a week.

The treatment program for mesothelioma depends on many factors, including:

1. The stage of the cancer.

2. Where the cancer is.

3. How far the cancer has spread.

4. How the cancer cells look under the microscope.

5. The patient’s age and desires.

Surgery

Surgery for pleural mesothelioma may be done for 1 of 2 reasons: to relieve pain and discomfort caused by the tumor (called palliation) or to cure.

Palliative surgery is typically done in cases where the tumor has already spread beyond the mesothelium and is difficult to remove completely, or if you are too ill to tolerate a more extensive operation.

Curative surgery is offered if you are in otherwise good health and the tumor is thought to be localized and can be removed completely. Unfortunately, the cancer cells tend to spread into the chest wall, around the heart, over nerves, and the diaphragm. It is often difficult to detect this spread. Because of this, doctors are not clear on the exact role of surgery. It is not likely to cure you but may extend your life. Curative surgery is being done in some cancer centers and a few of the patients who have had the surgery are experiencing long remissions of their disease.

Depending on the stage of a mesothelioma, surgery may be used to remove the cancer and some of the surrounding tissue. Often, however, an operation is not appropriate and you may have only smaller procedures to relieve symptoms.

A thoracentesis, where fluid in the chest is removed by placing a needle into the chest cavity, may be done to make a patient more comfortable. Sometimes talc or drugs that cause scarring may be injected into the chest cavity to try to prevent the fluid from returning. This is called pleurodesis. These techniques are successful in controlling the fluid, at least temporarily, in as many as 90% of patients. Because pleural fluid can compress the lung and cause shortness of breath, these procedures can help you breathe more easily, however, they do not cure the cancer.

In the case of peritoneal mesothelioma, a needle may be inserted into the abdomen to drain the fluid. Similarly, a needle inserted into the pericardium (sac around the heart) can drain pericardial fluid and help relieve circulatory problems. Sometimes the cancer cells spread along the needle path, and a tumor nodule may form under the skin of that area. This concern should not prevent fluid removal, though.

Two surgical procedures may be offered if you have pleural mesothelioma: pleurectomy/decortication and extrapleural pneumonectomy.

Pleurectomy/decortication: Pleurectomy/decortication is usually a palliative procedure (relieves symptoms without curing the cancer) in cases where the entire tumor cannot be removed. This procedure removes the pleura, where the majority of the tumor is located. It can control the build up of fluid improve breathing and decrease pain caused by the cancer.

Extrapleural pneumonectomy: Extrapleural pneumonectomy is a far more extensive operation and is most often used in patients with localized mesothelioma of the epithelioid type, when the surgeon thinks a cure is possible. It is a difficult operation and is done only by surgeons in large specialized medical centers. You should talk with your doctor about an appropriate treatment center nearest to your home. The operation removes the pleura lining the chest wall, diaphragm, pericardium, and the whole lung on the side of the tumor. The diaphragm and the pericardium are then reconstructed with prosthetic material. You must be in overall good health with no other serious illnesses to tolerate the surgery. This operation attempts to remove all or most of the cancer and some surrounding tissues as well.

Surgical treatment of peritoneal mesothelioma is often done either to help relieve symptoms or to remove the tumor from the wall of the abdomen and other digestive organs. As with pleural mesothelioma, these tumors are often too extensive to remove completely. Similar operations can be done to remove a mesothelioma from the pericardium (the sac around the heart).

Surgery for mesothelioma of the tunica vaginalis testis, which occurs in the groin, is also not usually curative. Most of the time surgery is done because the tumor resembles a hernia. The surgeon attempts to treat a suspected hernia and only realizes the diagnosis after the surgery is begun. This kind of mesothelioma can’t be entirely removed.

Chemotherapy

Chemotherapy is the use of drugs for treating cancer. The drugs can be swallowed in pill form or they can be injected by needle into a vein or muscle. Chemotherapy is systemic therapy. This means that the drug enters the bloodstream and circulates throughout the body (through the whole system) to reach and destroy the cancer cells.

To treat mesothelioma, these drugs may also be given intrapleurally (directly into the chest cavity) or intraperitoneally (into the abdominal cavity). Based on the type and stage of mesothelioma, chemotherapy may be given as the primary (main) treatment or as an adjuvant treatment (treatment given in addition to the primary treatment) to surgery. Chemotherapy for this disease is palliative and not curative.

Several chemotherapy drugs have been used to treat mesothelioma. The preferred combination of drugs for now is pemetrexed (Alimta), which is combined with cisplatin. Because pemetrexed interferes with normal metabolism of folic acid and vitamin B12, these must also be given to avoid side effects. Another combination that has a good response rate is cisplatin and gemcitabine. Another option substitutes cisplatin with carboplatin, which causes much less nausea and vomiting.

Other combinations of drugs used to treat mesothelioma include:

• methotrexate and vincristine

• cisplatin, vinblastine and mitomycin

• cisplatin and doxorubicin

• doxorubicin, cyclophosphamide (or ifosfamide), and cisplatin

All the drugs above can be given alone in people who may not be able to tolerate two drugs. Other drugs such as paclitaxel and irinotecan are being studied to determine their effectiveness in treating mesothelioma.

A new, related drug called raltitrexed has also been shown to help patients with mesothelioma when given with cisplatin. Patients who received these drugs lived longer than those who received cisplatin alone.

Chemotherapy drugs kill cancer cells but also damage some normal cells. Therefore, your doctor will pay careful attention to avoiding or minimizing side effects, which depend on the specific drugs, the amount taken, and the length of treatment. Temporary side effects might include nausea and vomiting, loss of appetite, loss of hair, and mouth sores.

Because chemotherapy can damage the blood-producing cells of the bone marrow, patients may have low blood cell counts. This can result in an increased risk of infection (due to a shortage of white blood cells); bleeding or bruising after minor cuts or injuries (due to a shortage of blood; platelets); or fatigue or shortness of breath (due to low red blood cell counts).

Most side effects disappear once treatment is stopped. There are remedies for many of the temporary side effects of chemotherapy. For example, you can be given drugs to prevent or reduce nausea and vomiting. If you experience any side effects, be sure to talk with your doctor.

Radiation Therapy

Radiation therapy is sometimes used as the main treatment of mesothelioma in some patients, especially those whose general health is too poor to undergo surgery. Radiation therapy uses high-energy x-rays to kill cancer cells.

External beam radiation therapy uses radiation delivered from outside the body that is focused on the cancer. This type of radiation therapy is the preferred type to treat mesothelioma. These treatments are much like getting a diagnostic x-ray except for a longer time. A typical course of treatment takes anywhere from 3 to 5 weeks of daily treatments (5 days a week). In general, though, mesothelioma is not helped much by radiotherapy because it is relatively resistant to the effects of radiotherapy. Also, the need to treat a large part of the lung leads to problems with lung damage.

Brachytherapy places radioactive material directly into the chest or the abdomen at the site of the mesothelioma. It is seldom used for this cancer.

Adjuvant radiation therapy can be used in addition to surgery to kill small deposits of cancer that cannot be seen and removed during surgery.

Palliative radiation therapy can also be used to ease symptoms of mesothelioma such as shortness of breath, pain, bleeding, and difficulty swallowing.

Side effects of radiation therapy may include fatigue and mild skin changes that resemble sunburn. Often these side effects are temporary. Radiation may also make the side effects of chemotherapy worse. Chest radiation therapy may cause lung damage and lead to difficulty breathing and shortness of breath. Abdominal radiation therapy may cause nausea, vomiting, and diarrhea. If you are having any of these side effects of radiation therapy, talk with your doctor since there are ways to help control these symptoms.

If fluid collects in the pleural space, radioactive drugs can be put into the space after the fluids are removed. Sometimes they are successful in preventing the fluid from coming back.

Clinical Trials

The purpose of clinical trials: Studies of promising new or experimental treatments in patients are known as clinical trials. A clinical trial is only done when there is some reason to believe that the treatment being studied may be valuable to the patient. Treatments used in clinical trials are often found to have real benefits. Researchers conduct studies of new treatments to answer the following questions:

• Is the treatment helpful?

• How does this new type of treatment work?

• Does it work better than other treatments already available?

• What side effects does the treatment cause?

• Are the side effects greater or less than the standard treatment?

• Do the benefits outweigh the side effects?

• In which patients is the treatment most likely to be helpful?

Types of clinical trials: A treatment is studied in 3 clinical trial phases before it is eligible for approval by the FDA (Food and Drug Administration).

Phase I clinical trials: The purpose of a phase I study is to find the best way to give a new treatment and how much of it can be given safely. The cancer care team watches patients carefully for any harmful side effects. The treatment has been well tested in lab and animal studies, but the side effects in patients are not completely known. Doctors conducting the clinical trial start by giving very low doses of the drug to the first patients and increasing the dose for later groups of patients until side effects appear. Although doctors are hoping to help patients, the main purpose of a phase I study is to test the safety of the drug.

Phase II clinical trials: These are designed to see if the drug works. Patients are given the highest dose that doesn’t cause severe side effects (determined from the phase I study) and are closely observed for an effect on the cancer. The cancer care team also looks for side effects.

Phase III clinical trials: Phase III studies involve large numbers of patients—often several hundred. One group (the control group) will receive the standard (most accepted) treatment. The other groups will receive the new treatment. Usually doctors study only 1 new treatment to see if it works better than the standard treatment, but sometimes they will test 2 or 3. All patients in phase III studies are closely watched. The study will be stopped if the side effects of the new treatment are too severe or if one group has had much better results than the others.

If you are in a clinical trial, you will receive excellent care. You will have a team of experts taking care of you and monitoring your progress very carefully. The study is especially designed to pay close attention to you.

However, there are some risks. No one involved in the study knows in advance whether the treatment will work or exactly what side effects will occur. That is what the study is designed to find out. While most side effects disappear in time, some can be permanent or even life threatening. Keep in mind, though, that even standard treatments have side effects. Depending on many factors, you may decide to enroll in a clinical trial.

Deciding to enter a clinical trial: Enrollment in any clinical trial is completely up to you. Your doctors and nurses will explain the study to you in detail and will give you a form to read and sign indicating your desire to take part. This process is known as giving your informed consent. Even after signing the form and after the clinical trial begins, you are free to leave the study at any time, for any reason. Taking part in the study will not prevent you from getting other medical care you may need.

To find out more about clinical trials, ask your cancer care team. Among the questions you should ask are:

• What is the purpose of the study?

• What kinds of tests and treatments does the study involve?

• What does this treatment do?

• What is likely to happen in my case with, or without, this new treatment?

• What are my other choices and their advantages and disadvantages?

• How could the study affect my daily life?

• What side effects can I expect from the study? Can the side effects be controlled?

• Will I have to be hospitalized? If so, how often and for how long?

• Will the study cost me anything? Will any of the treatment be free?

• If I am harmed as a result of the research, what treatment would I be entitled to?

• What type of long-term follow-up care is part of the study?

• Has the treatment been used to treat other types of cancers?

The American Cancer Society offers a clinical trials matching service for patients, their family, and friends. You can gain access to this service through the ACS cancer information center at 1-800-ACS 2345 or on our Web site at http://clinicaltrials.cancer.org. Based on the information you provide about your cancer type, stage, and previous treatments, our computer can compile a list of clinical trials that match your medical needs. In finding a center most convenient for you, the service can also take into account where you live and whether you are willing to travel.

Complementary and Alternative Therapies

Complementary and alternative therapies are a diverse group of health care practices, systems, and products that are not part of usual medical treatment. They may include products such as vitamins, herbs, or dietary supplements, or procedures such as acupuncture, massage, and a host of other types of treatment. There is a great deal of interest today in complementary and alternative treatments for cancer. Many are now being studied to find out if they are truly helpful to people with cancer.

You may hear about different treatments from family, friends, and others, which may be offered as a way to treat your cancer or to help you feel better. Some of these treatments are harmless in certain situations, while others have been shown to cause harm. Most of them are of unproven benefit.

The American Cancer Society defines complementary medicine or methods as those that are used along with your regular medical care. If these treatments are carefully managed, they may add to your comfort and well-being.

Alternative medicines are defined as those that are used instead of your regular medical care. Some of them have been proven not to be useful or even to be harmful, but are still promoted as “cures.” If you choose to use these alternatives, they may reduce your chance of fighting your cancer by delaying, replacing, or interfering with regular cancer treatment.

Before changing your treatment or adding any of these methods, discuss this openly with your doctor or nurse. Some methods can be safely used along with standard medical treatment. Others, however, can interfere with standard treatment or cause serious side effects. That is why it's important to talk with your doctor.

Treatment of Mesothelioma by Stage

Stage I: Many patients with stage I pleural mesothelioma have their cancer removed by pleurectomy/decortication or extrapleural pneumonectomy, as described in the section How Is Mesothelioma Treated. Patients with peritoneal mesotheliomas in an early stage might also benefit from surgery. The value of adjuvant chemotherapy or radiation therapy (treatments given after surgery) for stage I mesothelioma is being studied. Radiation therapy may be used if your general health is too poor to tolerate a major operation. Some doctors have had success with putting cisplatin into the thoracic space after the surgery. This can also be used in the abdomen for peritoneal mesothelioma.

Stages II, III: Treatment options include palliative and supportive care providing relief of symptoms, such as thoracentesis (to remove fluid accumulation in the chest cavity) along with pleurodesis, paracentesis (removing fluid from the abdomen), operations to remove as much of the tumor as possible in some cases, and radiation therapy or chemotherapy aimed at easing symptoms. Cure is usually not possible for patients in these stages. Enrollment in clinical trials evaluating the newest treatment possibilities in large medical centers should be considered. Some patients can have long remissions after extensive surgery by experts.

Other approaches include putting chemotherapy or radioactive drugs directly into the pleural space or abdominal cavity. This can be done simply with the doctor placing a needle into the pleural space or abdomen after numbing the skin with local anesthetic. Although this only kills some of the cancer cells, it often helps slow down fluid collection.

Stage IV: Because stage IV mesothelioma has spread to distant organs, a cure is not possible. The goals of using any aggressive therapy such as chemotherapy and radiation therapy should be clear to you and your family. You might want to consider enrolling in a clinical trial in a large medical center. These studies evaluate the newest treatment possibilities.

Supportive care may be the best choice, perhaps in the setting of a good hospice program. Pain management is an important aspect of your care. It is important for you to know that drugs are available to effectively treat pain due to mesothelioma. You should not hesitate to request pain medicines or discuss pain control problems with your cancer care team.

Staging is the process of finding out how far the cancer has spread. Staging of mesothelioma is based on imaging studies such as x-rays, CT scans, and MRI scans. The treatment and outlook for patients with mesothelioma largely depends on the stage (extent of spread) of their cancer. Since pleural mesothelioma occurs most frequently and has been studied the most, it is the only mesothelioma for which a staging classification exists.

The major staging system has recently been developed by the International Mesothelioma

Interest Group and adopted by the American Joint Committee on Cancer (AJCC). This is a TNM system, similar to staging systems used for most other cancers. T stands for tumor (its size and how far it has spread to nearby organs), N stands for spread to lymph nodes, and M is for metastasis (spread to distant organs).

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 has 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.

Medical History and Physical Exam

A complete medical history (interview) is taken to check for risk factors and symptoms. This will include questions to determine if you have been exposed to asbestos.

A physical exam will provide information about signs of mesothelioma and other health

problems. Patients with pleural mesotheliomas (mesotheliomas of the chest) often have fluid in their chest cavity (pleural effusion) caused by the cancer. Some will have fluid in the abdominal cavity (ascites) in cases of peritoneal mesothelioma, or fluid in the pericardium (pericardial effusion) in cases of pericardial mesothelioma. All these might be detected during a physical exam. Otherwise they will be found by imaging studies.

Rarely, mesothelioma can develop in the groin and look like a hernia.

Imaging Tests

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.

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.

Computed tomography (CT) scan: 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.

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) scan: 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

As mentioned above, blood levels of a protein called osteopontin are elevated in people with mesothelioma. But this blood test is probably more useful for following a patient’s progress during and after treatment. It is not used to diagnose the disease, although an elevated level may raise suspicions.

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. If cancer cells are present, special tests are needed to diagnose whether the cancer is a mesothelioma, a lung cancer, or another type of cancer.

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.

Certain findings on chest x-rays that suggest asbestos exposure could prompt the need for further tests or close follow-up. However, the chest x-ray is not an effective test for early detection of mesothelioma in the general population. One test being studied is a blood test that measures the levels in the blood of osteopontin, a protein that is elevated in people who have lung damage due to asbestos. It is even higher if a person develops mesothelioma.

The best way to prevent mesothelioma is to prevent or limit your exposure to asbestos in homes, in public buildings, and at work. People who may be exposed to asbestos at work include miners, factory workers, insulation manufacturers, railroad workers, ship builders, gas mask manufacturers, and construction workers, particularly those involved with insulation. If there is a possibility of on-the-job exposure, such as renovating old buildings, then you should use all protective equipment, work practices, and safety procedures designed for working around asbestos.

If you live in an older home, there may be asbestos-containing insulation or other materials. A knowledgeable expert can check your home to determine if there is any asbestos and if it poses any risk of exposure. This may involve testing the air for asbestos levels. It is often more dangerous to remove the materials containing asbestos than to leave them alone. You may then decide to have the asbestos removed from your home. You should hire a qualified contractor to perform this job, to avoid contaminating your home further or causing any exposure to the workers. You should not attempt to remove asbestos-containing material yourself.

A risk factor is anything that increases your chance of getting a disease such as cancer.

Different cancers have different risk factors.

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.

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.

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.