Moore AJ, Parker RJ, Wiggins J.

Department of Respiratory Medicine, Wexham Park Hospital, Wexham, Slough, Berkshire, UK. a.moore@ic.ac.uk

Abstract

Malignant mesothelioma is a fatal asbestos-associated malignancy originating from the lining cells (mesothelium) of the pleural and peritoneal cavities, as well as the pericardium and the tunica vaginalis. The exact prevalence is unknown but it is estimated that mesotheliomas represent less than 1% of all cancers. Its incidence is increasing, with an expected peak in the next 10-20 years. Pleural malignant mesothelioma is the most common form of mesothelioma. Typical presenting features are those of chest pain and dyspnoea. Breathlessness due to a pleural effusion without chest pain is reported in about 30% of patients. A chest wall mass, weight loss, sweating, abdominal pain and ascites (due to peritoneal involvement) are less common presentations. Mesothelioma is directly attributable to occupational asbestos exposure with a history of exposure in over 90% of cases. There is also evidence that mesothelioma may result from both para-occupational exposure and non-occupational “environmental” exposure. Idiopathic or spontaneous mesothelioma can also occur in the absence of any exposure to asbestos, with a spontaneous rate in humans of around one per million. A combination of accurate exposure history, along with examination radiology and pathology are essential to make the diagnosis. Distinguishing malignant from benign pleural disease can be challenging. The most helpful CT findings suggesting malignant pleural disease are 1) a circumferential pleural rind, 2) nodular pleural thickening, 3) pleural thickening of > 1 cm and 4) mediastinal pleural involvement. Involvement of a multidisciplinary team is recommended to ensure prompt and appropriate management, using a framework of radiotherapy, chemotherapy, surgery and symptom palliation with end of life care. Compensation issues must also be considered. Life expectancy in malignant mesothelioma is poor, with a median survival of about one year following diagnosis.

Glossary

prevalence

a measure of the proportion of persons in the population with a certain disease at a given time.

diagnosis

identifying a disease by its signs or symptoms, and by using imaging procedures and laboratory findings. The earlier a diagnosis of cancer is made, the better the chance for long-term survival.

chemotherapy

(key-mo-THER-uh-pee) treatment with drugs to destroy cancer cells. Chemotherapy is often used with surgery or radiation to treat cancer when the cancer has spread, when it has come back (recurred), or when there is a strong chance that it could recur.

benign

(be-nine) not cancer; not malignant.

mesothelioma

a tumor derived from mesothelial tissue, such as the peritoneum (lining the abdomen) or pleura (lining the lungs). More on mesothelioma.

tunica vaginalis

The serous sheath of the testis and epididymis, derived from the peritoneum; it consists of outer parietal and inner visceral serous layers.

peritoneal

(pair-uh-tuh-nee-al) the serous membrane that lines the cavity of the abdomen. (More on Peritoneal Mesothelioma.)

pleural effusion

an abnormal accumulation of fluid, usually caused by trauma or disease, in the pleural space.

ascites

(uh-sigh-tees) excess fluid accumulation in the abdominal (peritoneal) cavity.

Park EK, Hannaford-Turner KM, Hyland RA, Johnson AR, Yates DH.

Research and Education Unit, Workers’ Compensation Dust Diseases Board of NSW, Sydney, Australia.

Abstract

Asbestos is a fibrous silicate which is recognized as causing a variety of lung disorders including malignant mesothelioma of the pleura, lung cancer and asbestosis. Asbestos use has been banned in most developed countries but exposure still occurs under strict regulation in occupational settings and also occasionally in domestic settings. Although the hazards of asbestos are well known in developed countries, awareness of its adverse health effects is less in other parts of the world, particularly when exposure occurs in non-occupational settings. Experience of asbestos use and its adverse heath effects in developed countries such as Australia have resulted in development of expertise in the diagnosis and treatment of asbestos-related diseases as well as in screening and this can be used to help developing countries facing the issue of asbestos exposure.

Keywords: Asbestos, Mesothelioma, Asbestos-related diseases, Occupational exposure, Public health

Glossary

screening

the search for disease, such as cancer, in people without symptoms. For example, the principal screening measure for breast cancer is mammography. Screening may refer to coordinated programs in large populations.

pleura

(pler-uh) the membrane around the lungs and lining of the chest cavity. (Pleural mesothelioma.)

diagnosis

identifying a disease by its signs or symptoms, and by using imaging procedures and laboratory findings. The earlier a diagnosis of cancer is made, the better the chance for long-term survival.

cancer

malignancy; a group of diseases typified by abnormal, generally out-of-control, cell growth.

mesothelioma

a tumor derived from mesothelial tissue, such as the peritoneum (lining the abdomen) or pleura (lining the lungs). More on mesothelioma.

Pairon JC, Andujar P, Matrat M, Ameille J.

INSERM Unité 841, Créteil, France. JC.Pairon@chicreteil.fr

Abstract

Lung cancer and pleural mesothelioma are the most common occupational cancers.

Recent epidemiological studies have estimated that the fraction attributable to occupational factors varies from 13 to 29% for lung cancer in men and is about 85% for pleural mesothelioma in men. Previous occupational exposure to asbestos is the most common occupational exposure in these cancers. Mesothelioma immediately leads the clinician to look for past asbestos exposure. In contrast, the search for an occupational exposure that should be routine in all cases of lung cancer, is generally more difficult because of the number of occupational aetiological factors and the absence of criteria that allow distinction of an occupational cancer from a tobacco related one.

Therefore attention should be paid to the identification of occupational exposure in order to set up primary prevention programmes to prevent exposure still present in the working environment and, on the other hand, to identify the subjects entitled to the acknowledgement of occupational disease and/or to obtain the compensation available to asbestos victims.

Keywords: Asbestos, Silicon dioxide, Occupational diseases, Lung, Carcinogens

Glossary

DES

abbreviation for diethylstilbestrola (die-eth-l-steh-BES-ter-ol),  synthetic form of estrogen.

cancer

malignancy; a group of diseases typified by abnormal, generally out-of-control, cell growth.

mesothelioma

a tumor derived from mesothelial tissue, such as the peritoneum (lining the abdomen) or pleura (lining the lungs). More on mesothelioma.

Schneider F, Sporn TA, Roggli VL.

Department of Pathology, Duke University Medical Center, Durham, North Carolina 27710, USA. frank.schneider@duke.edu

Abstract

This study reports changes in the frequency of detection of various asbestos fiber types between 1982 and 2005. Crocidolite is increasingly detected in U.S. mesothelioma patients. The percentage of crocidolite fibers detected in lung tissue has risen from 4 to 10%, and the percentage of cases in which crocidolite was detected increased from 19 to 37%. Meanwhile, the frequency of detection of amosite and chrysotile has decreased. The authors performed a detailed analysis of cases in which crocidolite was identified in the absence of amosite. Most of such cases were identified in recent years, a finding of concern since crocidolite is considered the most potent fiber type with respect to the pathogenesis of mesothelioma.

Keywords: amosite; amphiboles; asbestos; crocidolite; mesothelioma

Glossary

detection

finding disease. Early detection means that the disease is found at an early stage, before it has grown large or spread to other sites. Note many forms of cancer can reach an advanced stage without causing symptoms. Mammography can help to find breast cancer early, and the PSA blood test is useful in finding prostate cancer.

tissue

a collection of cells, united to perform a particular function.

mesothelioma

a tumor derived from mesothelial tissue, such as the peritoneum (lining the abdomen) or pleura (lining the lungs). More on mesothelioma.

Reid A, Heyworth J, de Klerk N, Musk AW.

Occupational Respiratory Epidemiology, School of Population Health, M431, University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia. Alison.Reid@uwa.edu.au

Abstract

Objectives: Knowledge of mortality patterns following exposure to asbestos has been determined mostly from cohort studies of men who were exposed to asbestos in their workplace. Women are more likely to have obtained their asbestos exposure domestically or from their environment.

Methods: 2552 women and girls are documented to have lived in the blue asbestos mining and milling township of Wittenoom between 1943 and 1992 and were not involved in asbestos mining or milling. Quantitative asbestos exposure measurements were derived from periodic dust surveys undertaken in the industry and around the township. Death records were obtained for the period 1950–2004. Standardised mortality ratios (SMRs) were calculated to compare the Wittenoom women’s mortality with that of the Western Australian female population.

Results: There were 425 deaths, including 30 from malignant mesothelioma. There was excess mortality for all causes of death (SMR = 1.13), all neoplasms (SMR = 1.42), symptoms, signs and ill defined conditions (SMR = 6.35), lung cancer (SMR = 2.15) and pneumoconiosis (SMR = 11.8). Mortality from cancer of the ovary (SMR = 1.52), upper aerodigestive cancers (SMR = 2.70) and tuberculosis (SMR = 5.38) was increased but not significantly. The risk of death from mesothelioma was increased, but not significantly, in residents known to have lived with or washed the clothes of an Australian Blue Asbestos Company asbestos worker (HR = 2.67, 95% CI 0.77 to 9.21; HR = 2.61, 95% CI 0.85 to 7.99, respectively).

Conclusion: Women who were former residents of Wittenoom, exposed to asbestos in their environment or in their home, have excess cancer mortality, including mesothelioma, compared with the Western Australian female population.

Glossary

mortality

a measure of the rate of death from a disease within a given population.

epidemiology

(ep-uh-deem-ee-AHL-uh-gee) the study of diseases in populations by collecting and analyzing statistical data. In the field of cancer, epidemiologists look at how many people have cancer; who gets specific types of cancer; and what factors (such as environment, job hazards, family patterns, and personal habits, such as smoking and diet) play a part in the development of cancer.

cancer

malignancy; a group of diseases typified by abnormal, generally out-of-control, cell growth.

mesothelioma

a tumor derived from mesothelial tissue, such as the peritoneum (lining the abdomen) or pleura (lining the lungs). More on mesothelioma.

Berry G, Pooley F, Gibbs A, Harris JM, McDonald JC.

School of Public Health, University of Sydney, Sydney, Australia. geoffb@health.usyd.edu.au

Abstract

A cohort of 1,154 employees, mainly women, who had worked 1940-1945 on the manufacture of military gas masks using filter pads containing 20% crocidolite, was traced through 2003, by which time 65 were known to have died from mesothelioma. The last known death with mesothelioma was in 1994, whereas a further 5 cases would have been expected in those with known duration of exposure. Lung tissue samples, from 50 deaths from mesothelioma and 20 other causes, had been analyzed for mineral fiber content. For ten of the mesothelioma cases data on fiber size were collected. Crocidolite fiber concentrations were analyzed in relation to exposure by time and duration. Fiber concentrations overall fell fairly steadily by decade of death, and increased with length of exposure up to 36 months and then fell sharply. The annual rate of elimination estimated by regression was 7.5% corresponding to a half life of 9.2 years. The proportion of fibers longer than 6 μm increased over time implying that the shorter fibers were eliminated more rapidly than the longer ones. The decline in concentrations with time confirms the hypothesis that crocidolite and, by inference, other amphibole fibers are slowly removed from the lung, but since the longer more carcinogenic fibers were cleared more slowly it is unclear to what extent this clearance explains the slowing down of the increase in mesothelioma mortality from about 40 years from the most recent exposure. The exact biostatistical models which most closely conform with the data remain open to question.

Glossary

mortality

a measure of the rate of death from a disease within a given population.

tissue

a collection of cells, united to perform a particular function.

mesothelioma

a tumor derived from mesothelial tissue, such as the peritoneum (lining the abdomen) or pleura (lining the lungs). More on mesothelioma.

Sichletidis L, Chloros D, Spyratos D, Haidich AB, Fourkiotou I, Kakoura M, Patakas D.

Laboratory for the Study of Environmental Diseases, Pulmonary Clinic of Aristotle University of Thessaloniki, Thessaloniki, Greece.

Abstract

Background: Asbestos exposure is related to serious adverse health effects. However, there is disagreement about the relationship between chrysotile exposure and mesothelioma or lung cancer.

Objectives: Our aim was to investigate the mortality rate among workers exposed to relatively pure chrysotile in an asbestos cement factory.

Patients and Methods: In an asbestos cement plant opened in 1968, we prospectively studied all 317 workers. A quantity of 2,000 tons of chrysotile, with minimal amphibole contamination, was used annually until 1 January 2005. Asbestos fiber concentration was measured regularly. Date and cause of death were recorded among active and retired workers.

Results: Asbestos fiber concentration was always below permissible levels. Fifty-two workers died during the study. The cause was cancer in 28 subjects; lung cancer was diagnosed in 16 of them. No case of mesothelioma was reported. Death was attributed to cardiovascular diseases in 23 subjects and to liver cirrhosis
in 1. Overall mortality rate was significantly lower than that of the Greek general population, standardized mortality ratio (SMR) was 0.71 (95% CI 0.53-0.93). Mortality due to cancer was increased (SMR 1.15, 95% CI 0.77-1.67), mainly due to lung cancer mortality (SMR 1.71, 95% CI 0.98-2.78), but not significantly.

Conclusions: Occupational exposure to relatively pure chrysotile within permissible levels was not associated with a significant increase in lung cancer or with mesothelioma. Decreased overall mortality of workers indicates a healthy worker effect, which – together with the relatively small cohort size – could have prevented small risks to be detected.

Keywords: Asbestos, Epidemiology, Lung cancer, Mesothelioma, Chrysotile

Glossary

mortality

a measure of the rate of death from a disease within a given population.

epidemiology

(ep-uh-deem-ee-AHL-uh-gee) the study of diseases in populations by collecting and analyzing statistical data. In the field of cancer, epidemiologists look at how many people have cancer; who gets specific types of cancer; and what factors (such as environment, job hazards, family patterns, and personal habits, such as smoking and diet) play a part in the development of cancer.

cancer

malignancy; a group of diseases typified by abnormal, generally out-of-control, cell growth.

mesothelioma

a tumor derived from mesothelial tissue, such as the peritoneum (lining the abdomen) or pleura (lining the lungs). More on mesothelioma.

Betti M, Neri M, Ferrante D, Landi S, Biava A, Gemignani F, Bertolotti M, Mirabelli D, Padoan M, Ugolini D, Botta M, Bonassi S, Magnani C, Dianzani I.

Department of Medical Sciences, University of Piemonte Orientale, Via Solaroli 17, 28100 Novara, Italy.

Abstract

Malignant mesothelioma (MM) is a rare and aggressive tumor of the pleura. The most important causal factor for the development of MM is occupational exposure to asbestos. Different lines of evidence suggest a role of genetic background in MM development, as for other cancers. Two published studies observed an association between MM and N-acetyl-transferase 2 (NAT2) polymorphisms. First, a Finnish study observed that the NAT2 slow acetylator phenotype was associated with an increased risk of MM. Conversely, MM risk was higher in Italian subjects carrying the NAT2 fast acetylator genotypes. The conflicting results obtained in Finland and Italy could be ascribed to random chance, considering the small panel of patients and controls in the two studies, but also ethnic or other differences may have been important. To ascertain the role of NAT2 genotype, we performed a study on 252 MM patients and 262 controls recruited in two Northern Italy areas that were characterized by high asbestos exposure, due to intense industrial activities (an asbestos cement factory in Casale Monferrato, mainly shipyards and refineries in Liguria). Unconditional multivariate logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs). NAT2 fast acetylator genotypes showed an increased OR, although not statistically significant, both in asbestos-exposed subjects (OR=1.47; 95% CI=0.96–2.26) and in the entire population (OR=1.38; 95% CI=0.93–2.04). These results suggest that NAT2 polymorphisms do not exert a strong effect on individual susceptibility to MM.

Keywords: Asbestos; Mesothelioma; N-acetyltransferase; Oxidative stress; Single nucleotide polymorphism

Glossary

pleura

(pler-uh) the membrane around the lungs and lining of the chest cavity. (Pleural mesothelioma.)

tumor

an abnormal lump or mass of tissue. Tumors can be benign (not cancerous) or malignant (cancerous).

mesothelioma

a tumor derived from mesothelial tissue, such as the peritoneum (lining the abdomen) or pleura (lining the lungs). More on mesothelioma.

Cioffredi LA, Jänne PA, Jackman DM.

Dana-Farber Cancer Institute, Boston, Massachusetts 02115, USA.

Abstract

Peritoneal mesothelioma is a rare and often aggressive malignancy, mostly affecting asbestos exposed adults. We present four pediatric peritoneal cases treated with a cisplatin-based doublet regimen, the standard of care in the systemic therapy of adult mesothelioma. Treatment was well tolerated, and three of these patients have achieved long-term survival. The fathers of three of the patients worked in the construction industry and may have been the source of indirect asbestos exposure.

Keywords: chemotherapy, pediatric oncology, solid tumors

Glossary

therapy

any of the measures taken to treat a disease. Unproven therapy is any therapy that has not been scientifically tested and approved. Use of an unproven therapy instead of standard (proven) therapy is called alternative therapy. Some alternative therapies have dangerous or even life-threatening side effects. For others, the main danger is that a patient may lose the opportunity to benefit from standard therapy. Complementary therapy, on the other hand, refers to therapies used in addition to standard therapy. Some complementary therapies may help relieve certain symptoms of cancer, relieve side effects of standard cancer therapy, or improve a patient's sense of well-being. The ACS recommends that patients considering use of any alternative or complementary therapy discuss this with their health care team.

systemic therapy

treatment that reaches and affects cells throughout the body; for example, chemotherapy.

regimen

(rej-uh-men) a strict, regulated plan (such as diet, exercise, or other activity) designed to reach certain goals. In cancer treatment, a plan to treat cancer.

oncology

(on-call-o-jee) the branch of medicine concerned with the diagnosis and treatment of cancer.

chemotherapy

(key-mo-THER-uh-pee) treatment with drugs to destroy cancer cells. Chemotherapy is often used with surgery or radiation to treat cancer when the cancer has spread, when it has come back (recurred), or when there is a strong chance that it could recur.

cancer

malignancy; a group of diseases typified by abnormal, generally out-of-control, cell growth.

mesothelioma

a tumor derived from mesothelial tissue, such as the peritoneum (lining the abdomen) or pleura (lining the lungs). More on mesothelioma.

peritoneal

(pair-uh-tuh-nee-al) the serous membrane that lines the cavity of the abdomen. (More on Peritoneal Mesothelioma.)

Reid A, Berry G, Heyworth JS, de Klerk N, Musk AB.

University of Western Australia, Australia

Abstract

Introduction: Nearly 3,000 women and girls were documented to have lived at the blue asbestos mining and milling town of Wittenoom, in Western Australia between 1943 and 1992. Eight percent of deaths among these women to the end of 2004 have been from malignant mesothelioma of the pleura. AIM: To predict future mortality from mesothelioma to 2030 in this cohort.

Methods: Mesothelioma mortality rates incorporating parameters for cumulative exposure, a power of time since first exposure and annual rates of fibre clearance from the lung were calculated from maximum likelihood estimates. These rates plus age specific mortality rates for Western Australian females incorporating an excess lung cancer risk were then applied to all the Wittenoom cohort women surviving to the end of 2004, in yearly increments, to predict the future numbers of cases of mesothelioma to 2030.

Results: There were 40 deaths from mesothelioma among the Wittenoom women to the end of 2004. Using a range of models that incorporate time since first exposure, competing risks from other diseases, latency periods and clearance of mesothelioma from the lungs we predict 66 (lowest estimate) to 87 (highest estimate) deaths from mesothelioma until 2030. This represents one and a half to two and a half times the number of deaths that have already occurred to the end of 2004.

Conclusion: The high toll from mesothelioma in this cohort of women and girls will continue well into the future.

Glossary

pleura

(pler-uh) the membrane around the lungs and lining of the chest cavity. (Pleural mesothelioma.)

mortality

a measure of the rate of death from a disease within a given population.

cancer

malignancy; a group of diseases typified by abnormal, generally out-of-control, cell growth.

mesothelioma

a tumor derived from mesothelial tissue, such as the peritoneum (lining the abdomen) or pleura (lining the lungs). More on mesothelioma.