It`s not known what causes the initial genetic mutations that lead to mesothelioma, although researchers have identified factors that may increase the risk. It is likely that cancer develops due to an interaction between many factors such as hereditary diseases, your environment, your health status and your lifestyle choices. In a meta-analysis of phase II studies conducted between 1965 and 2001, cisplatin was the only active agent for the treatment of unresectable malignant pleural mesothelioma.41 Cisplatin served as the backbone for most duplicate treatments. In 2003, a randomized phase III study compared cisplatin alone with cisplatin plus pemetrexed in untreated pleural mesothelioma.42 With the combination, the response rate was 41.3% compared to 16.7% for cisplatin alone (P< 0.0001). The median time to progression was 5.7 vs. 3.9 months (P = 0.001) and median overall survival was 12.1 versus 9.3 months (P = 0.02), both in favour of the combined arm. Therefore, the combination of cisplatin and pemetrexed is considered the standard first-line treatment for unresectable malignant pleural mesothelioma. It has also become a standard recommendation in the adjuvant combination modality approach for resectable diseases. When mesothelioma metastasizes, they most often affect the liver, adrenal gland, kidneys or other lungs.
[16] If you think you may be exposed to asbestos at work or at home, there are steps you can take to limit your exposure and reduce your risk of mesothelioma. Ask your employer if you are at risk of inhaling asbestos in your workplace. Be sure to follow all safety rules set by your employer, including wearing protective equipment or showering and changing work clothes before returning home. If you live in an older home, it is safer to leave the asbestos where it is than to remove it. By breaking down asbestos fibers, they are released into the air, making them easy to inhale. If you think your home contains asbestos, contact a professional to test the air to determine if you are at risk. Staging When a person is diagnosed with mesothelioma, an assessment is also needed to determine the extent or “stage” of the disease. Staging is important to determine how far the disease has spread, characterize the potential course of the disease, and determine appropriate treatment approaches. Some of the diagnostic tests described above can be used in staging mesothelioma.
Even if the disease is confined to the breast, a doctor may need to perform a procedure called mediastinoscopy (similar to other techniques above) to take biopsies of the lymph nodes in the central region (mediastinum) of the breast, or laparoscopy to rule out spread to the abdomen, as X-ray tests may miss the disease in these areas. There is no consensus staging system for mesothelioma; At least six different staging systems have been proposed in the medical literature. Symptoms of mesothelioma vary depending on the location, type and stage of the cancer. Unfortunately, many people have no symptoms early in the disease and the tumor can be difficult to see on X-rays. Talc exposure is also a risk factor for mesothelioma; Exposure may affect those who live near talc mines, work in talc mines, or work in talc plants. [25] Exposure to asbestos fibres has been recognized as an occupational health hazard since the early 20th century. Numerous epidemiological studies have linked occupational exposure to asbestos with the development of pleural plaques, diffuse pleural thickening, asbestosis, carcinoma of the lungs and larynx, gastrointestinal tumours and diffuse malignant mesothelioma of the pleura and peritoneum. Asbestos is widely used in many industrial products, including cement, brake pads, seals, roof shingles, floors, textiles, and insulation.
[40] The most common symptoms of peritoneal mesothelioma are abdominal swelling and pain due to ascites (accumulation of fluid in the abdominal cavity). Other features may include weight loss, fever, night sweats, loss of appetite, vomiting, constipation, and umbilical hernia. [15] If the cancer has spread beyond the mesothelium to other parts of the body, symptoms may include pain, difficulty swallowing, or swelling of the throat or face. These symptoms can be caused by mesothelioma or other less serious conditions. [ref. needed] Epithelioid mesothelioma is characterized by high levels of calretin. [11] The effectiveness of radiation therapy compared with chemotherapy or surgery for malignant pleural mesothelioma is unknown. [70] The main risk factor for mesothelioma is exposure to asbestos.
Asbestos is a heat- and fire-resistant mineral fibre used in insulation and flame retardant materials before the 1970s. Although its use has been banned for more than 30 years, professions such as mining or machining, electricians, plumbers, pipe builders, insulators or even renovating old homes still pose a high risk of exposure. The longer you are exposed to large amounts of asbestos, the more likely you are to develop mesothelioma. That said, most people exposed to asbestos never develop mesothelioma. When pleural mesothelioma spreads into the chest, it puts pressure on the structures in that area. This can lead to complications, such as: Arginine, a semi-essential amino acid in humans, is essential for some cancers, including mesothelioma. Argininosuccinate synthetase catalyzes a rate-limiting step in arginine synthesis. Downregulation of this enzyme makes the cell dependent on extracellular sources of arginine, a process known as arginine aseotrophy. Several tumors have shown this dependence, including mesothelioma.
In these arginine-dependent cells, the degradation of arginine by pegylated forms of the enzyme arginine deiminase may prove to be a novel anticancer approach.66,67 Phase I/II studies of this process have shown activity in hepatocellular carcinomas and melanoma, 2 types of tumors known as auxotrophic arginine. A similar examination of malignant pleural mesothelioma is warranted and is being considered (verbal communication with Paolo Rodriguez, Stanley S. Scott Cancer Center, Louisiana State University, New Orleans, LA, May 2011). Asbestos fibers have been shown to alter the function and secretory properties of macrophages, ultimately creating conditions conducive to the development of mesothelioma. After phagocytosis of asbestos, macrophages produce increased amounts of hydroxyl radicals, which are normal by-products of cellular anaerobic metabolism.