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Methods for Early Stage Diagnosis

The key to long term survival is early diagnosis. The use of biomarkers and new advances in radiology, technology, science and medicine are making detection and distinquishing types of cancer easier. If mesothelioma is diagnosed at an earlier stage then combined treatment (often referred to as multmodality treatment) involving surgery, radiation, chemotherapy plus new alternative therapies might be effective at prolonging life and increasing quality of life.

Malignant mesothelioma is a cancer that begins in the mesothelium, which is the cells in the lining of the lungs, heart, or abdomen. The three main types of mesothelioma are:

  • Pleural - occurs in the lining of the lungs;
  • Peritoneal - occurs in the lining of the abdominal cavity.
  • Pericardial - occurs in the lining of the heart;

Of the three, pleural mesothelioma is the most common.

Mesothelioma is caused by exposure to asbestos. Asbestos is a naturally occurring fibrous mineral that was once commonly used in heating insulation, vinyl flooring, roofing materials, brake linings, and other industrial products. In most cases, exposure is caused occupationally, especially in jobs such as construction, plumbing, factory work, and ship building and repair. Some cases of mesothelioma are caused by secondary exposure, such as a young child hugging their father when he comes home from work covered in asbestos dust. Even more rare are cases caused by environmental exposure.

The symptoms of mesothelioma can vary and do not develop until ten to fifty years after exposure to asbestos. Upon initial exposure, asbestos fibers are inhaled, penetrate the lungs, and lodge in the lining of the chest, lungs, or abdomen, causing damage that does not show signs until decades later. Because of this, the disease is more commonly diagnosed in people who are in their fifties or older, although more recently there have been a few cases of adolescents as young as thirteen.

Besides avoiding all exposure to asbestos, the next best line of defense is to diagnose mesothelioma early on, before it has progressed beyond Stage I or II. However, the long lag time between exposure and developing symptoms can make it very difficult to diagnose mesothelioma accurately and before it has advanced to late stages.

Symptoms can vary greatly, making it very difficult for doctors and pathologists to diagnose the progressive disease. Some typical symptoms may include:

  • chest pain and/or tightness,
  • breathlessness,
  • weight loss / loss of appetite,
  • sweating,
  • persistent and productive cough,
  • nausea and intestinal upset.

A combination of accurate exposure history along with exams by qualified radiologists and pathologists is essential in making an accurate diagnosis. A known history of exposure to asbestos is especially important; however because of the delay between exposure and symptoms developing, many do not realize the importance of or can not recall being exposed.

Along with getting a complete medical and work history, several other diagnostic steps are usually taken. To do these, a medical team of doctors, radiologists and pathologists take samples of pleural fluid and usually a pleural biopsy, chest xray, and/or CT scan as part of the diagnosis. Despite positive results for cancer, the challenge still exists in determining the type and location of the cancer. Even when a cells are examined, mesothelioma cells can be very similar to those of other lung cancer cells.

To help increase accuracy of diagnosis, several researchers are trying to find alternative ways of identifying mesothelioma. One effort is to find a biomarker that specifically identifies mesothelioma. A tumor or bio-marker is a chemical that is given off by cancer cells that are then carried in the blood. Different types of cancer have different chemicals, so when a blood test is performed it can help identify the type of malignancy.

Another type of biomarker that shows promising signs of being able to be used as a screening tool for mesothelioma is soluble mesothelin related protein (SMRP). In cases of malignant mesothelioma, there is an increased presence of mesothelin. Researchers are continuing to investigate the accuracy of biomarkers, and particularly SMRP, as an identifier of malignant mesothelioma.

More recently, researchers are finding that a good diagnostic tool is to look at several markers, or what they refer to as a panel of stains or immunohistochemical tests. This panel would include markers that are likely to react to mesothelioma tumors (positive markers, usually including SMRP) and markers that are not expected to react with these tumors (negative markers). By using a select panel, the medical team can more easily distinquish between mesothelioma and other types of non-asbestos related cancers.

Although there are numerous completed and in-process studies about the use of markers as a tool for early diagnosing, no consensus has been reached about which are the best markers or even if they are reliable enough to become a standard diagnositic tool. Despite this, there has been such progress in finding alternative ways to diagnose and treat this incurable cancer. The results of such scientific efforts has led to increased chances of longer survival and better quality of life. This is hopeful for anyone suffering from mesothelioma.

Two other hopeful diagnostic tools are the miRview(TM) meso test by Rosetta Genomics, Ltd., and a high resolution CT scan combined with using Vitrea(R), a new imaging software program developed by Vital Images, Inc. The miRview(TM) meso is a molecularly-based test that can distinguish mesothelioma from other types of lung cancer. For more information or for physicians to order this commercially available test, contact 1-888-522-7971 or visit the company's website.

The enhanced CT scan technology was announced last weekend at the Asbestos Disease Awareness Organization conference. The new technology allows doctors to see the asbestos-related cancers earlier than current standard scans, and also allows them to view it in three dimensional detail. For more information call 1-800-KARMANOS or visit Karmanos Cancer Institute. Karmanos Cancer Institute is heavily involved in research around asbestos-related diseases and dedicated to finding ways to prevent, detect and cure cancer.