Epidemiological Features of Mesothelioma

Epidemiological Features of Mesothelioma in Egypt

Asbestos and Mesothelioma in the last 20 years in Egypt
Zakaria and coworkers (1989) diagnosed 13 (9 females and 4 males) mesothelioma patients between 1984 - 1987 which came from an area of ~4.7 km radius in the neighborhood of Sigwart El-Maasara Company, south Cairo (Table 1). None of the cases had a history of occupational asbestos exposure, but all had been living near the Sigwart El-Maasara Company. In the period 1989 - 1999, 148 cases of mesothelioma were diagnosed and treated at NCI, Cairo University. Females represented 36.5%, with male to female ratio of 1.7. Residential asbestos exposure was 81.1% whereas occupational exposure was 13.5% (Eldin et al., 2005).

Age and sex of patients with pleural mesothelioma during the
period 1984‐1987 (Zakaria et al., 1989)

In the first 4 years of the 3rd millennium (2000 - 2003), 635 cases of mesothelioma were diagnosed at NCI and ACH, Cairo. Both hospitals drain and serve most of the high risk populations living in the neighborhoods of the Sigwart Companies (Eldin et al., 2005). The median age was 53 years (19 - 90). Females represented 39.2% and young adults ≤40 years represented 19.1%. Residential exposure was evidenced in 64.7% of cases (Shoubra El Kheima, 35.6%, El Maasara, 23.6%, El Zeytoon 5.2% and other
exposed areas 0.5%). Twenty five percent of the mesothelioma cases came from other Cairo areas while 9.8% came from other governorates (Eldin et al., 2005) (Table 2). The NCI hospital-based registry showed an increase in the relative frequency of MPM from 0.47% in the year 2002 to 1.3% in the year 2003.

Epidemic features of mesothelioma in Egypt during the periods
1989‐2003 (Eldin et al., 2005)

Hussin (2007) studied the epidemic mesothelioma among 487, 2 913, and 979 people occupationally, environmentally and control, exposed to asbestos in Shoubra El-Kheima, north Cairo, respectively. He recorded a total of 88 MPM cases, among them 4 cases were occupational, 83 environmental and 1 non-exposed person (Table 3). MPM was more prevalent in the environmentally exposed group (83/2 913, 2.8%) than in the occupationally exposed group (4/487, 0.8%) and control group (1/979, 0.1%) (Table 3). The control area was an agricultural village located at Banha city ~40 km north of the asbestos plant. People who agreed to be included in the study were 979 people chosen by cluster sampling, a response rate of 94%. None of those individuals had a history of occupational or environmental exposure to asbestos fibers.

The prevalence of MPM cases among environmentally, occupationally and non‐exposed groups
in different areas surrounding Sigwart Shoubra El Kheima over the period 2003‐2005 (Hussin, 2007)

There was a significantly (P<0.001) higher prevalence of MPM cases in El-Wehda Arabia area (4.5%) which lies 100 m away from the asbestos company compared to Ezbet Osman area which had the lowest prevalence (1.1%). Moreover, there was a significant positive correlation (P<0.001) between airborne asbestos fibre counts and number of mesothelioma cases among environmentally exposed patients (Hussin, 2007). The mean age of patients with MPM was 51.3 years; 54.1 ± 8.5 years (range 39 - 70 years) for males and 49.5 ± 7.4 years (range 35 - 60 years) for females (Hussin, 2007). Females and males represented 61.4% and 38.6% of MPM cases respectively, diagnosed between Shoubra El-kheima,s residents (Hussin, 2007). Evidence from other countries. Sheard et al. (1991) found that the mean age of MPM cases was 54.1 years.

The median latency from time of asbestos exposure to disease development is ~32 years and ranged from 20 to ~50 years (Pass et al., 2005). The shortest lag time between first exposure and death with mesothelioma was 20 years for residents compared with 13 years in the former workers (Berry et al., 2004). For exposures starting at age 30, the excess mortality estimate is applied to the total expected mortality from age 40 to age 79 and about 70% of survivors to age 30 will die between the ages of 40 and 80 years in Cappadocia, Turkey (Umran, 2003). Incidence of mesothelioma was found to be higher in populations living near naturally occurring asbestos than those non-exposed.

Mesothelioma is rare between cohorts that are not exposed to asbestos, but it is frequent in workers who are exposed to it (Sluis-Kremer, 1991). In central Cappadocia, Turkey mesothelioma caused 50% of all deaths in three villages, Tuzköy, Karain, and Sarihidir. Initially, this was attributed to erionite, a zeolite mineral with similar properties to asbestos, however, detailed epidemiological investigation showed that erionite causes mesothelioma mostly in families with a genetic predisposition (Umran, 2003).

There was statistically significant interaction between asbestos exposure, mesothelioma and sex (Reid et al., 2007). The rate of mesothelioma is higher in males and those ≥15 years of age at first exposure, but women had a steeper dose-response curve than men; however their risk was lower than that for men (Reid et al., 2007). Reid et al. (2008) concluded that women who were former residents of Wittenoom, Western Australia, exposed to asbestos in their environment or in their houses, had excess cancer mortality including mesothelioma compared with the Western Australian female population. Madkour et al. (2009) attributed the predominance of MPM cases between females in the vicinity of Sigwart Company (Shoubra El-Kheima) to their long duration of residency.