Document Mo4N4n4V97jO7be1LkLazB99

43. Neoplasms of the Pleura 561 account for around 1% of all deaths. In 2005 Hodgson et al.67 stated there were 1848 mesothelioma deaths in Great Britain in 2001 and mesothelioma deaths were predicted to peak at around 1950 to 2450 per year between the years 2011 and 2015 (Fig. 43.1). The Health and Safety Executive Data68 suggested the peak would occur earlier than originally predicted and the maximum would be approximately 2000 deaths in or around the year 2010. According to Treasure et al.,69 one in every 100 men born in the 1940s will die of malignant pleural mesothelioma.... For a man first exposed as a teenager, who remained in a high-risk occupation such as insulation throughout his working life, the lifetime risk of mesothelioma can be as high as 1 in 5.... The disease is increasing in frequency.... We will see many more mesotheliomas in the next 25 years. In the developed world alone, 100,000 people alive will now die from it. In Australia, mortality from MM was stated to have been increasing since 1975. Mesothelioma incidence rates are among the highest in the world, and the Australian Mesothelioma Registry received 6129 mesothelioma notifications between 1986 and 2000. Of the mesotheli oma cases with past asbestos exposure, close to 89% were work-related, about 3% were not work-related, and about 8% could not be classified. Of the persons who developed work-related MM, one in three worked in the construc tion industry and one in five worked in the manufacturing industry. In contrast, Roggli,70 based on his experience, suggests that a mesothelioma epidemic was beginning to wane in the U.S. Lemen,7! using Surveillance Epidemiology and End Results (SEER) data and International Classifica tion of Diseases (ICD-10-TEM) coding that went into effect in 1999, stated the accuracy for reporting mesothe lioma was about 80% effective, which would mean that in the U.S. there were over 6000 cases of mesothelioma per year. Etiology Asbestos The association of asbestos exposure and the develop ment of mesothelioma has been reviewed in detail.72-74 The chronology of asbestos is shown in Box 43.1 (Figs. 43.2 and 43.3). Asbestos is the single most im portant causative agent of mesothelioma. Numerous Box 43.1. The History of Asbestos 4000 BCE 2000-3000 BCE 2500 BCE 800-900 AD 1000 1300-1.400 Early 1700s 1724 1828 1853 1866 1896 1900 1913 1919 1939-1945 1945-1975 1990s Asbestos was used for wicks in lamps and candles. "Asbestos" means inextinguishable or unquenchable. Embalmed bodies of Egyptian pharaohs were wrapped in asbestos cloths to offset the ravages of time. Used in Finland to strengthen clay pots. Anecdotal evidence of Charlemagne's tablecloth made from woven asbestos. Mediterranean people used chrysotile from Cyprus and tremolite from upper Italy for the fabrication of cremation clothes, mats, and wicks for temple lamps. Marco Polo visited an asbestos mine in China in the latter half of the 13th century. He concluded that asbestos was a stone and lay to rest the myth that asbestos was the hair of a woolly lizard. Asbestos papers and boards were made in Italy. Benjamin Franklin brought a purse made of asbestos to England. The purse is now in the Natural History Museum. United States patent issued for asbestos insulating material used in steam engines. Asbestos helmet and jackets worn by Parisian Fire Brigade. Molded lagging material made from water, glass, and asbestos. First asbestos brake linings were made by Ferodo Ltd., in England. High pressure asbestos gaskets made by Klinger in Austria. First asbestos pipes developed in Italy. Standard corrugated sheet asbestos introduced in Australia by Hardies. Wartime use included fireproof suits and parachute flares. In the film The Wizard of Oz in 1939, the Wicked Witch of the West appeared on a broom made of asbestos. Postwar construction projects relied heavily on the use of asbestos, reaching an all-time high in 1973. The solid fuel boosters of the space shuttle are insulated with asbestos, one of the few remaining current uses. 562 S.P. Hammar et al Figure 43.2. Canadian chrysotile fibers as visualized by scan ning electron microscopy (SEM). The individual fibers are long and wavy (serpentine). Figure 43.3. Scanning electron microscopy appearance of South African crocidolite fibers. In comparison to chrysotile fibers (Figure 43.2), these ampbiboie fibers are straight and show evidence of longitudinal splitting. reports31,59 75"86 have tabulated the percentage of mesothe lioma cases associated with asbestos exposure (Table 43.3). The association between asbestos exposure and mesothelioma is stronger in men than in women and, in many series, very few women with mesothelioma have had a history of exposure to asbestos. The threshold amount of asbestos necessary to induce mesothelioma is unknown, although in most reports a dose-response rela tionship has been suggested87,88; that is, persons with a greater intensity and duration of exposure to asbestos have a higher incidence of mesothelioma. Small concen trations of asbestos may induce mesothelioma89"97 (see Table 43.3. Association of exposure to asbestos and incidence of mesothelioma Sex distribution Cases associated with asbestos exposure Reference Number of cases Male Unspecified Female Male Unspecified Female Borow et al.'5 Cochrane and WebsterTM Tagnon et ai.7/ Whifweil and Rawcliffe78 Hammar'9 Taylor and Johnson80 Vogelzang et al.81 Newhouse and Thompson-'5 Peto et ai.S3 McDonald and McDonald59 Roggli et al.83 Oels et a!.84 Brenner et al.85 Ratzer et al.86 72 70 61 52 151 30 31 83 116 557 25 37 123 31 64 8 55/55 (100%) W 61 0 45/56 (80%) 40 12 35/40 (87,5%) 119 32 66/82 (80%) 23 7 17/23 (74%) 22 9 13/22 (59%) 41 42 24/41. (59%) 116 0 69/116 (59%) 395 162 188/344 (55%) 21 4 11/21 (52%) 32 5 10/32 (31%) 84 39 16/84(19%) 21 10 4/31" (13%) 60/70" (86%) 5/5 (100%) 8/12 (67%) 10/22 (45%) 0/7 (0%) 2/9 (22%) 17/42 (40%) 8/162 (5%) 0/4 (0%) 0/5 (0%) 0/39 (0%) "Gender not specified. 43. bel< hol ar ma; rep yon exp hol pie' dur hoi exp bot Hu no the anc dea 198 Ital pie' occ int om con occ pos ma' I me: tos. dor Prc Eri Thi inji has mir Bai Tu; hac In yea the fou in i fou of' san boi me et of] 43- Neoplasms of the Pleura 563 below). Malignant mesothelioma can occur via house hold exposure to asbestos.98 Vianna and Polan" reported a relative risk of 10 for such situations compared to matched controls unexposed to asbestos. Kane et al.100 reported 10 cases of MM in patients 40 years old or younger. In seven of the 10 cases, there was asbestos exposure--two occupational exposures and five house hold exposures. Cazzadori et al.101 reported a case of pleural MM in a 37-year-old woman exposed to asbestos during childhood. From birth to age 10 she lived in a house next to an asbestos-processing factory. Asbestos exposure was confirmed by finding 0.3 asbestos bodies per milliliter in her bronchoalveolar lavage fluid. Huncharek'52 pointed out that exposure to asbestos was no longer confined to asbestos industry workers, and there were nonoccupational hazards such as household and building occupant exposures. Dodoli et al.102 reviewed death certificates of 39,650 persons between 1975 and 1988 in Livorno, Italy and in 45,900 persons in La Spezia, Italy, between 1958 and 1988. A total of 262 cases of pleural mesothelioma were recorded, most of which occurred in persons occupationally exposed to asbestos in the shipbuilding industry. Thirteen cases of mesotheli oma occurred in women who washed the asbestoscontaminated work clothes of their relatives, and six cases occurred in persons domestically exposed to asbestos, possibly from installing fireproof or nonconductive materials. In 1997 Hammar et al.103 reported on 103 women with mesothelioma of whom about 70 were exposed to asbes tos, the most common source of asbestos exposure being domestic bystander exposure. Proposed Nonasbestos Causes of Mesothelioma Erionite Theoretically, MM might develop at the site of pleural injury caused by almost any agent. Of particular interest has been a group of naturally occurring fibrous silicate minerals called zeolites. In 1975 and subsequent years, Baris and colleagues104-108 reported that people living in Tuskoy and Karain (two small villages in central Turkey) had the highest incidence of mesothelioma in the world. In Karain, 21 of 50 deaths recorded in people over 20 years old during a 5-year period were caused by meso thelioma. People living in this region of Turkey were found to have very fine fibers of a zeolite called erionite in their sputum and lung tissue. These fibers were not found in similar specimens of people living in other areas of Turkey. A search for asbestos in soil, rock, and water samples was negative and it was hypothesized that air borne erionite fibers from building materials caused the mesotheliomas. Lillis109 substantiated the findings of Baris et al. Sebastien and coworkers110 demonstrated that 93% of ferruginous bodies from lung samples of two patients with MM from Tuskoy were formed on erionite cores. Wagner et al.111 induced mesotheliomas in 38 of 40 rats inoculated with erionite. Rohl et al.,112 however, were able to identify small amounts of tremolite and chrysotile in addition to erionite in environmental samples taken from Tuskoy and Karain (see Nonasbestos and Nonoc cupational Mineral Fibers and Mesothelioma, below). They also reported that erionite was found in environ mental samples taken from villages with no reported cases of mesothelioma. Recent studies have suggested a genetic susceptibility to mesothelioma in Turkey based on identification of mesothelioma in one village and not in another.113-114 Chronic Pleural Inflammation and Scarring In 1985 Hillerdal and Berg115 reported two patients who developed mesothelioma in regions of pleural scarring caused by tuberculosis that had been treated with pneu mothorax. They reviewed the literature and found 20 additional cases of malignant tumors in pleural scars, 12 of which were found in areas of squamous carcinoma. They reported that squamous carcinoma was the most common tumor associated with scarring from chronic empyema and extrapleural pneumothorax. Malignant mesotheliomas have occurred years after chronic inflam matory lesions of the pleura; for example, chronic empyema or packing of the pleural cavity with leucite spheres as treatment for tuberculosis (so-called piombage therapy). Also, there are a few reports (about eight cases) of an association of peritoneal mesothelioma with familial Mediterranean fever (FMF), possibly related to recurrent FMF serositis.116 Cases of this type are excep tional, and confounding factors for mesothelioma need to be addressed; for example, in relation to FMF, cases of mesothelioma have been reported in the Mediterranean littoral from white-washing of homes with tremolitecontaining material, so that domestic and environmental tremolite exposure might represent a potential confound ing factor for the association of FMF and mesotheli oma.117118 In addition, most cases of postinflammatory mesothelioma with a short interval between inflamma tion and tumor are probably mesotheliomas that pre sented with a burst of inflammatory activity, perhaps related to production of cytokines or mediators of inflam mation such as interleukin-8, before their final diagnosis as mesothelioma.119,120 Irradiation The literature contains multiple reports of mesothelioma following exposure to ionizing radiation,121-150 and excess rates of MM have also been reported among both Danish and German patients exposed to radio-active thorium dioxide (Thorotrast) for radiologic procedures.121,124,134,13-''