Mesothelioma may be caused by exposure to ultramafic rock

Everyday exposure to naturally occurring asbestos increases the risk of developing malignant mesothelioma, according to a study by UC Davis researchers.

The study - the largest to examine the question - will be published this fall in the American Journal of Respiratory and Critical Care Medicine.

Exposure to asbestos in the workplace, particularly in shipyards, has long been recognized as a risk factor for mesothelioma, a rare form of cancer affecting the lining of the lung. But in the new study, researchers found a consistent and dose-dependent association between mesothelioma and residential proximity to ultramafic rock, the predominant source of naturally occurring asbestos.

"Our findings indicate that the risks from exposure to naturally occurring asbestos, while low, are real and should be taken seriously," said Marc Schenker, professor and chair of the UC Davis Department of Public Health Sciences and the study's senior author. "This study provides important supportive evidence that naturally occurring asbestos causes mesothelioma - and public efforts should now shift to understanding the risk and how we can protect people from this preventable malignancy."

To put the mesothelioma risk in perspective, the disease kills about the same number of Americans each year as passive smoking. About 2,500 people a year die from mesothelioma in the United States, according to National Institute of Occupational Safety and Health statistics. About 3,000 deaths a year are attributed to exposure to secondhand tobacco smoke, according to U.S. Environmental Protection Agency statistics.

Ultramafic rock is distributed throughout the Sierra Nevada, Coast Ranges and Klamath Mountains in Northern and Central California, and has been a source of increasing concern as new housing developments cut through these areas. Of most concern are the areas of ultramafic rock associated with tremolite asbestos.

In their ambitious study, Schenker and his colleagues used California Cancer Registry data to identify 2,908 cases of malignant mesothelioma diagnosed between 1988 and 1997 in adults ages 35 and older. In most cases, the registry also provided occupational history. As a control group, an equal number of age- and gender-matched pancreatic cancer cases was selected (since pancreatic cancer has no known association to asbestos exposure). For both the mesothelioma and pancreatic cancer cases, the researchers employed sophisticated geographic information system mapping to pinpoint home or street addresses for every diagnosed individual. A map from the California Department of Conservation, Division of Mines and Geology, served as the reference for ultramafic rock deposits. Finally, statistical adjustments were made for sex, occupational asbestos exposure and age at diagnosis.

The researchers found that the risk of developing malignant mesothelioma was directly related to residential proximity to a source of ultramafic rock. Specifically, the odds of having mesothelioma fell by 6.3 percent for every 10 kilometers (about 6.2 miles) farther a person lived from the nearest asbestos source. The association was strongest in men, but was also seen in women. No such association showed up in the pancreatic cancer group. The study was not designed to determine the "ground zero" risk for those living closest to an asbestos source - only to test for a relationship between proximity and risk.

"This is very creative, painstaking epidemiology," said Jerrold L. Abraham, professor and director of environmental and occupational pathology at SUNY Upstate Medical University in Syracuse, New York, and a leading authority on mesothelioma. "The UC Davis researchers have shown a significant association between living near deposits of naturally occurring asbestos and mesothelioma. This is the strongest evidence possible without conducting one-on-one interviews with each diagnosed mesothelioma patient or his or her family."

Laurel Beckett, professor and vice chair of the UC Davis Department of Public Health Sciences and a study co-author, said the findings are important. "We showed that breathing asbestos in your community is not magically different from breathing asbestos in an industrial setting. It would have been a surprise to find otherwise."

Similarly, she said, it was no real surprise to scientists when passive smoking was found to cause lung cancer. "Like smoking, exposure to asbestos appears to be very dose-dependent," Beckett said. "Day-in, day-out occupational exposures are more dangerous than intermittent exposures in the community. But the more you can do to reduce your personal exposure, the safer you will be."

While the overall mesothelioma rate was about one case per 100,000 people per year in the California study, the rate varied markedly by gender and age. For white males, the rate was 2.29 cases per 100,000. For white females, it was 0.49. People over age 60 had ten times the rate of those ages 40 to 59.

Worldwide, epidemiological studies of mesothelioma have found occupational causes for most but not all cases of the disease. In some undeveloped areas of the world, including parts of Greece and Turkey, mesothelioma cases have been linked to use of naturally occurring asbestos in household materials such as whitewash. The UC Davis study suggests naturally occurring asbestos also causes mesothelioma in developed countries, through incidental, non-occupational exposures.

California has required statewide cancer reporting since 1985 and established the California Cancer Registry in 1988. One of the largest cancer databases in the world, the registry is responsible for collecting cancer incidence and mortality statistics for more than one tenth of the United States population. An estimated 98.9 percent of all mesothelioma cases diagnosed in California are reported to the registry.

The registry's size enabled researchers to identify an association that might not have been apparent in a smaller study.

Needed now are field studies to more accurately characterize determinants of exposure to asbestos fibers among residents in areas with naturally occurring asbestos, Schenker said. In addition, he said more must be learned about the types and size of fibers in asbestos deposits, the types of human activities that disturb asbestos fibers and the determinants of cancer risk in exposed populations.

"Because mesothelioma takes 20 to 30 years to develop, what we learn today will allow us to protect Californians from this preventable cancer decades into the future," Schenker said.

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Mesothelioma Chemotherapy

Chemotherapy is often one component of mesothelioma treatment that is difficult for the lay person to grasp. Part of the problem is that the literature dealing with this subject is jargon intensive. The other problem is that the science and research are ever advancing. Understanding chemotherapy is truly a moving target. As a nurse, I can assist in cutting through some of the medical jargon, but I would be remiss if I didn't inform patients at the beginning that the principle source of information should be their oncologist, or cancer specialist doctor.

Your oncology doctor is reading all the latest research, and is highly motivated to defeat your cancer, and extend your life. Ask all of your questions without holding back.

All three of the basic approaches to treating mesothelioma; surgery, radiation therapy, and chemogtherapy, are potentially frightening to a patient. Chemotherapy is perhaps a little more difficult to penetrate rationally, and weigh the risks, versus rewards. Certainly, the list of possible side effects is quite intimidating. Mesothelioma, however, is a killer and you must trust your oncologist as he will want to throw everything that he thinks can work at this disease.

If surgery is an option for you, it may be followed by radiation therapy, and/or chemotherapy in order to try to kill the microscopic cancer cells that remain in your body.

The chemotherapy agents that your doctor selects will often be a combination or recipe of drugs that when used together have better outcomes than when used by themselves.

One of the medications that you may encounter is Cisplatin. Cisplatin messes up the DNA strands inside cancer cells by crossing them during cell division and causing these abnormal DNA-crossed cells to die. Another medication , doxorubicin forms free radicals that fracture the DNA strands inside cancer cells. Pemetoexed slows or stops tumor growth by blocking cell enzymes required for the production of RNA and DNA. There are many others, and there are treatment programs that combine medications with radiation. Your treatment will be customized for your specific needs.

All chemotherapy agents have some possible side effects. Remember though, drugs affect different people differently. Fatigue affects many cancer patients, often due to anemia. You will probably be taking high potency vitamins to help combat this. Other blood changes that may occur are low platelets, affecting blood clotting, and low white blood cells, which can affect your resistance to infection. You may experience various gastrointestinal problems, such as vomiting, nausea, diarrhea, or constipation. You may also develop yeast infections, and sores in the mouth. There is also a condition known as "chemo brain". "Chemo brain" is difficulty concentrating, focusing, fuzziness, and poor memory. Side effects may cause you to make some lifestyle changes during the chemotherapy treatment. These side effects ease and go away after the round of chemo is complete.

When you are receiving chemotherapy, what is happening is that the chemo is attacking the cancer cells. Unfortunately, some of the normal cells are also affected. This is why most of the side effects occur. The normal cells that are affected are primarily the fast growing cells. Cancers themselves are fast growing cells. Normal fast growing cells are the bone marrow, where blood cells are produced, the blood cells themselves, the digestive tract including the mouth and stomach, and the hair follicles. Some drugs affect vital organs as well.

Your close relationship with your oncologist is very important. Defeating mesothelioma is a team effort, and he is your quarterback. You are the team owner, so you must play an active role.

Ed Desmond is a small business owner, and works as a Registered Nurse. For more on mesothelioma treatment see Mesothelioma Treatment Articles and resources about mesothelioma treatment.

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Everithing About Mesothelioma

Mesothelioma is a form of cancer that is normally caused by asbestos exposure. Mesothelioma is cancer that occurs in the mesothelium.

Mesothelioma:
Mesothelioma is a type of cancer affecting the cells of mesothelial lining in the chest and abdomen. Mesothelioma cancer can develop in the tissues covering the lungs or the abdomen. Mesothelioma has also been found in the stomach and other abdominal organs but it is much rarer in those areas than are both pleural mesothelioma and peritoneal mesothelioma. Mesothelioma can also occur in the ovaries and scrotum. Mesothelioma invades the chest wall or the esophagus during the second stage.Mesothelioma also takes a long time to develop (typically 15-40 years), so patients today could have been exposed prior to the 1980s when asbestos was not highly regulated. Mesothelioma is not caused by smoking, as lung cancer so often is.

Symptoms:
Symptoms One of the most common symptoms of mesothelioma is an accumulation of fluid between the lining of the lung and the chest cavity. Symptoms include:abdominal painascites, or an abnormal buildup of fluid in the abdomen a mass in the abdomen problems with bowel function weight loss. Symptoms such as trouble swallowing, pain, or swelling of the neck and face can be indications that the cancer has spread beyond the mesotheliom to other parts of the body. Symptoms of pleural mesothelioma include persistent pain in the chest and severe difficulty breathing caused by pleural effusion, or an accumulation of fluid in the pleural lining Cough, weight loss, and fever are also common symptoms. Symptoms of peritoneal mesothelioma include weight loss and abdominal pain and swelling due to a buildup of fluid in the abdomen. Symptoms of mesothelioma may not appear until 20 to 50 years after exposure to asbestos.

Diagnosis:
The key to long-term survival from treatment of mesothelioma is early diagnosis, which enables the greatest potential for success from standard therapies. Diagnosis begins with a review of the patient's medical history, including any history of asbestos exposure. Diagnosis of Mesothelioma is based on a pathological exam, more commonly referred to as a biopsy.Since this disease can be hard to diagnosis and costly to treat, it may require the consultation of an experienced attorney. When conclusive diagnosis cannot be made from fluid samples, diagnosis is often made through a surgical procedure called a throrascopy.The average age at diagnosis of mesothelioma is between 50 and 70 years old, with men being affected three to five times more often than women. The diagnosis may be suspected with chest X-ray and CT scan, and is confirmed with a biopsy (tissue sample) and microscopic examination. The median survival time is 17 months, with ten percent of patients living for three years after diagnosis.

Conclusion:
Mesothelioma is a deadly cancer which is fairly rare although in the last few decades the number of people who have died from it have dramatically increased. Mesothelioma is a rare form of cancer, but the deadliest one of all. Mesothelioma is a rare form of cancer and only affects between 2,000 and 3,000 people in the United States per year. Mesothelioma is less common in African Americans than in white Americans. Mesothelioma is rare in people under age 55. National Cancer Institute stats show that 3000 new diagnosis of malignant mesothelioma is reported each year. Mesothelioma is not always fatal and that is the hope to hold on to.

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