Risk Factors for Mesothelioma

Risk Factors for Mesothelioma

Mesothelioma is a rare but deadly cancer that affects the linings of various organs. Asbestos exposure is the No. 1 risk factor for mesothelioma, but other risk factors also have been identified. Mesothelioma is a deadly cancer that affects the mesothelium. The mesothelium is the membrane, like a net, that covers many organs in the body, such as the lungs and the heart. It has two layers: One covers the organ, the other acts like a sac, letting the organ move, if necessary.

People who develop mesothelioma have usually been exposed to a substance that infiltrated the mesothelium.

Mesothelioma Risk Factors: Long-Term Asbestos Exposure

Among the risk factors for mesothelioma, exposure to asbestos dust is by far the most important. About 70 percent to 80 percent of mesothelioma patients report a history of asbestos exposure at work.

And because asbestos was widely used in industry, car manufacturing, and construction until just a few decades ago, millions of U.S. workers had long-term exposure to asbestos and still are at risk for the disease. Leading the list are:

• Asbestos miners
• Shipyard workers
• Makers of asbestos products and textiles
• Workers in the heating and construction industries

Mesothelioma Risk Factors: Short-Term Asbestos Exposure

Many more people with shorter or less intensive exposure to asbestos face reduced but still real risks. For instance, demolition workers, firefighters, drywall removers, asbestos removal workers, and automobile workers may also be exposed to asbestos fibers. Even family members of asbestos workers may be exposed to asbestos dust because the workers bring it home on their clothing.

One particular group that may be at elevated risk are the crews involved in the cleanup of the World Trade Center in New York City after 9/11. Asbestos was used in the construction of the North Tower and it is estimated that hundreds of tons of asbestos were among the debris.

The risks posed by asbestos exposure can be hard to quantify, but in general risk depends on:

• The quantity of asbestos the person was exposed to
• The length of time the person was exposed
• The size, shape, and chemistry of the asbestos fibers
• Personal risk factors, such as smoking

There are two main forms of asbestos, amphibole (straight fibers) and chrysotile (curly fibers). Although all asbestos is dangerous, recent studies suggest that exposure to amphibole asbestos may pose a greater risk of mesothelioma than chrysotile asbestos because amphibole fibers remain in the lungs longer.

Mesothelioma Risk Factors: Genetic Possibilities

While it is clear that the risks climb with more intensive exposure over longer periods of time, some people have gotten mesothelioma after only brief exposure to asbestos, while others who were intensively exposed do not.

"There is a lot of work being done to try to find links to genetic predisposition to the disease," says Timothy Winton, MD, an associate professor of surgery, and division director of thoracic surgery, of the University of Alberta in Edmonton, Canada. "There is also often a co-morbid history of smoking or a genetic predisposition to smoking-related problems. With many cancers — and mesothelioma is one of them — you may need multiple hits from different carcinogens before you develop the disease."

Mesothelioma Risk Factors: Simian Virus 40 (SV40)

In the 1950s some polio vaccines were contaminated with SV40, which has been shown to cause mesothelioma in laboratory animals. In humans, an association between SV40 and mesothelioma has been suggested because SV40 has been found in human mesothelioma tumors, but no clear connection has been established.

Mesothelioma Risk Factors: Thorium Dioxide and X-Ray Imaging

Some studies have linked the use of the X-ray radioactive contrast medium thorium dioxide (Thorotrast) to an increased incidence of cancer, including mesothelioma.

One study found that a group exposed to thorium dioxide had a cumulative incidence of peritoneal mesothelioma (the peritoneum lines the stomach cavity) as much as 0.6 percent higher than asbestos-exposed workers. Thorium dioxide has not been used in X-ray imaging for many years.

Mesothelioma Risk Factors: Zeolites

Zeolites are minerals found naturally in volcanic rock and ash that contain hydrated aluminum and silicon. In synthetic forms, zeolites are used in detergents, for water and air purifications, and in other uses. Exposure to airborne zeolite dust has been associated with high incidence of mesothelioma in Turkey. In one Turkish village, a form of zeolite used to whitewash houses caused pleural mesothelioma incidence to soar to 440.9 per 100,000 for women and 298.1 per 100,000 for men.(source everydayhealth)

Mesothelioma Prognosis

What factors help determine a mesothelioma prognosis?

When an individual is diagnosed with mesothelioma or any other kind of cancer, one of the first questions they will have is “How long do I have to live?” This is a scary question - and a hard one to ask - but one for which most cancer patients will eventually seek an answer.
It is often very difficult for oncologists and members of a patient’s medical team to give a definitive answer to this query. Indeed, every case is different and cancer can be an unpredictable disease. Sometimes, cases that look hopeless turn out to be not so bleak. In other cases, cancers that don’t look so bad progress quickly and result in an untimely death.
Overall, the prognosis has been rather grim for mesothelioma patients during these past few decades. Malignant mesothelioma is extremely aggressive and has a long latency period. Hence, cases are usually not detected until the disease has reached the advanced  stages of cancer. As a result the prognosis for such patients is often not favorable: the meothelioma survival rate following diagnosis is usually just a year or two. That doesn’t mean, however, that there won’t be exceptions and that this dour outlook will not change in years to come, especially as more and better treatments are developed.

Determining Prognosis

Currently, a number of different issues determine the mesothelioma patient’s prognosis. These include:
Type – Mesothelioma is classified as one of three types, depending on the tissues involved. The epithelial type accounts for about 50 percent of all cases, sarcomatoid mesothelioma  is seen in 15 percent of diagnosed patients, and 35% have the mixed type of the disease. Those with epithelial mesothelioma have a better survival rate than the other types.
Location - Mesothelioma is also classified on the basis of location. For example,pleural mesothelioma  , which attacks the lining of the lung, is the most common, accounting for approximately 8o percent of all cases. Those with this type of cancer have the best rate of survival. Peritoneal mesothelioma, found in the lining of the abdomen, is the next most common and is diagnosed in about 10 -15 percent of mesothelioma victims. It is generally harder to treat. Less common types are very difficult to treat, including pericardial and testicular mesothelioma.
Stage of the disease - The prognosis for mesothelioma cancer depends on how early the disease is diagnosed and how soon treatment can begin. Because of the disease’s extended latency period, it is often not diagnosed until it has reached Stage 3 or 4, when mesothelioma symptoms finally appear. Sadly, many of these symptoms are common to a wide range of respiratory diseases including many that are less serious, like the flu or pneumonia. This often results in misdiagnosis.
Metastasis - When a mesothelioma diagnosis is finally made, oncologists will often find that the cancer has spread - or “metastasized” - from the location of the primary tumor - usually the pleura - to other parts of the body, often to the nearby organs as well as the lymph nodes. The extent of the metastases will determine what type of treatment is recommended as well as the prognosis.
General health of the patient - Simply put, younger and stronger patients with mesothelioma live longer than those of advanced age who have extant health problems. Seniors are often dealing with issues like heart disease, diabetes, and high blood pressure, making mesothelioma surgery as well as traditional cancer treatments much more risky and severely limiting treatment options.

Additional Mesothelioma Prognosis Factors

Mesothelioma Life Expectancy

Life expectancy for those diagnosed with malignant mesothelioma depends on a number of factors including, general patient health, cancer stage at diagnosis, and the eligibility of the patient for certain treatment options. Those diagnosed with early stage cancer and in generally good health will have a more favorable prognosis than those diagnosed with later-stage disease.
Mesothelioma Survival Rate
Most survival rates for cancer are quoted in regards to what is commonly known as the relative five-year survival rate. This indicates the number of patients who are still alive five years after they are diagnosed with the disease. Currently, the five-year survival rate for mesothelioma victims is just 10 percent. Though this seems like a grim number, it is indeed higher than it was about 10 years ago and much higher than it was 20-30 years ago.
The current one-year survival rate for mesothelioma patients is about 40 percent. This has also increased significantly in the last 10 years. Unfortunately, however, the prognosis for most mesothelioma patients remains poor overall. Many still die less than a year after diagnosis, with the average survival rate being 10-11 months, according to the American Cancer Association.
Mesothelioma Remission
Mesothelioma is one of the most aggressive types of cancer and can quickly metastasize from its origin into the lungs, abdominal cavity, and lymph nodes. As a result, very few mesothelioma patients go into remission. However, if treated properly and early enough, many patients have been able to extend survival rates long beyond previous expectations. Treatment options include surgical resection, chemotherapy, and mesothelioma radiation.
Mesothelioma Survivors
While there is currently no cure for mesothelioma, many patients have had success in managing their cancer with not only traditional treatments like chemotherapy and surgical methods, but also through the use of nutritional supplements, palliative therapies, and body-stress reduction techniques. Some patients diagnosed with mesothelioma have survived many years after what was an initially unfavorable prognosis.

Improving the Mesothelioma Prognosis

During the last decade, the plight of mesothelioma sufferers has gained more attention and more research dollars have been funneled towards the study of this disease and the discovery of new and novel drugs and treatments to provide more hope of a better prognosis for the mesothelioma sufferer.
Scientists have been working on new tests that strive to diagnose the disease at an earlier stage. For example, the Mesomark® assay is a simple blood test that measures the rate of Soluble Mesothelin-Related Peptides (SMRP) in the blood. This biomarker is released by mesothelioma cells into the bloodstream and SMRP can be elevated for many years before symptoms appear and an actual diagnosis of the disease is made. This tool for early diagnosis could potentially save hundreds of lives.
Treatments with new chemotherapy drugs Like Alimta and procedures that deliver more targeted radiation to the tumor have also helped to add to a mesothelioma patient’s life expectancy. In addition, experimental treatments such as immunotherapy, gene therapy, and photodynamic therapy have shown some success in treating this difficult disease.
Each new step in the field of mesothelioma research improves the mesothelioma prognosis little by little and provides additional hope for mesothelioma-affected individuals and their loved ones.
Source
http://www.cancer.org/Cancer/MalignantMesothelioma/OverviewGuide/malignant-mesothelioma-overview-survival-rates