Asbestos and the law

In the late 19th century and early 20th century, asbestos was considered an ideal material for use in the construction industry. It was known to be an excellent fire retardant, to have high electrical resistance, and was inexpensive and easy to use.

The dangers related to asbestos arise mainly when the fibers become airborne and are inhaled. Because of the size of the fibers, the lungs cannot expel them. These fibers are also sharp and penetrate internal tissues.

Society and Culture Sufferers of Mesothelioma

Mesothelioma, though rare, has had a number of notable patients :

• Bernie Banton, an Australian workers' rights activist, fought a long battle for compensation from James Hardie after he contracted mesothelioma after working for that company. He claimed James Hardie knew of the dangers of asbestos before he began work with the substance making insulation for power stations.

Society and Culture Sufferers of Mesothelioma

Mesothelioma eventually took his life along with his brothers' and hundreds of James Hardie workers'. James Hardie made an undisclosed settlement with Banton only when his mesothelioma had reached its final stages and he was expected to have no more than 48 hours to live. Australian Prime Minister Kevin Rudd mentioned Banton's extended struggle in his acceptance speech after winning the 2007 Australian federal election.

Prognosis and Epidemiology Mesothelioma

Prognosis

Mesothelioma has a poor prognosis. The median survival time for pleural mesothelioma is 12 months from diagnosis. Women, young people, people with low-stage cancers, and people with epithelioid cancers have better prognoses.

Negative prognostic factors include sarcomatoid or biphasic histology, high platelet counts (above 400,000), age over 50 years, white blood cell counts above 15.5, low glucose levels in the pleural fluid, low albumin levels, and high fibrinogen levels. Several markers are under investigation as prognostic factors, including nuclear grade, and serum c-reactive protein. Long-term survival is rare.

Multimodality Therapy Mesothelioma

All of the standard approaches to treating solid tumors - radiation, chemotherapy, and surgery - have been investigated in patients with malignant pleural mesothelioma.

Although surgery, by itself, is not very effective, surgery combined with adjuvant chemotherapy and radiation (trimodality therapy) has produced significant survival extension (3–14 years) among patients with favorable prognostic factors.

Immunotherapy Mesothelioma

Treatment regimens involving immunotherapy have yielded variable results. For example, intrapleural inoculation of Bacillus Calmette-Guérin (BCG) in an attempt to boost the immune response, was found to be of no benefit to the patient (while it may benefit patients with bladder cancer).

Immunotherapy Mesothelioma

Mesothelioma cells proved susceptible to in vitro lysis by LAK cells following activation by interleukin-2 (IL-2), but patients undergoing this particular therapy experienced major side effects. Indeed, this trial was suspended in view of the unacceptably high levels of IL-2 toxicity and the severity of side effects such as fever and cachexia.

Chemotherapy of Mesothelioma

Chemotherapy is the only treatment for mesothelioma that has been proven to improve survival in randomised and controlled trials. The landmark study published in 2003 by Vogelzang and colleagues compared cisplatin chemotherapy alone with a combination of cisplatin and pemetrexed (brand name Alimta) chemotherapy in patients who had not received chemotherapy for malignant pleural mesothelioma previously and were not candidates for more aggressive "curative" surgery.

This trial was the first to report a survival advantage from chemotherapy in malignant pleural mesothelioma, showing a statistically significant improvement in median survival from 10 months in the patients treated with cisplatin alone to 13.3 months in the group of patients treated with cisplatin in the combination with pemetrexed and who also received supplementation with folate and vitamin B12.

Prevention, Treatment, Screening, Staging of Mesothelioma

Prevention of mesothelioma

Mesothelioma can be prevented in most cases by preventing exposure to asbestos. The US National Institute for Occupational Safety and Health maintains a recommended exposure limit of 0.1 asbestos fiber per cubic centimeter.

Prevention, Treatment, Screening, Staging of Mesothelioma

Staging

Staging of mesothelioma is based on the recommendation by the International Mesothelioma Interest Group. TNM classification of the primary tumor, lymph node involvement, and distant metastasis is performed. Mesothelioma is staged Ia–IV (one-A to four) based on the TNM status.

Immunochemistry of Mesothelioma

Immunohistochemical studies play an important role for the pathologist in differentiating malignant mesothelioma from neoplastic mimics, such as breast or lung cancer that has metastasized to the pleura.

Micrographs showing mesothelioma in a core biopsy.

There are numerous tests and panels available, but no single test is perfect for distinguishing mesothelioma from carcinoma or even benign versus malignant. The positive markers indicate that mesothelioma is present; if other markers are positive it may indicate another type of cancer, such as breast or lung adenocarcinoma.