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la Medicina del Lavoro ~\Ied Lav 2005; 96,4: 354-359

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Peculiar features of mesothelioma occurrence as related

to exposure patterns and circumstances in the Lombardy

Region,Italy

ANGELA CECILIA PES:-\TORl, C-\ROLINA NIENSI

Departmem of Occuparional Health, University of j\Iilan, Italy

KEYWORDS

lVIesothelioma, National Registries

SUVlVIARY

Baekground: The ''Lombardy ivJesothelioma Registl/' started its activity in 2000 in accordance with ltalian lawDL 277/91. Objectives and methods: The Registry collects ali new incident cases of NJalignant Nlesothelioma(iV]NJ) of pleura, peritoneum, pericardium and vaginal tunic of testis occurring in residents in the Lombardy Re-

gion (Northern ltaly). For each "possible case" reported to the Registry by Lombardy hospitals, diagnosis is ascer-

tained according to ISPESL Guidelines. For confirmed eases, a standardized questionnaire is administered to the

subject or next-of-kin, to verifY sourees of lifetime asbestos exposure. Descriptive results are given jr cases collected

in 2000-2001. Age standardized incidence rates jr the year 2000 were ca!culated jr males and ftmales. Results:After revision of clinical records, diagnosis was judged as "certain" ND1;J in 307 (60%) subjects, probable in 63(12%) and possible in 33 (6%) subjeets. 21 were peritoneal mesothelioma. Standardized ratesjr pleural mesothe-lioma were respective/y 3.7 and 1.4 per 100,000 jr males and ftmales. Occupational asbestos exposure was ascer-tained jr 71% of male cases and 26% of ftmales. Exposure was unknown in 11 % and 27% of males and ftmalesrespective/y. The main relevant exposures were in building trades, metal manulacturing, machine production and

maintenance; an unexpected/y high proportion 01ftmale cases was engaged in non-asbestos textile factories. Con-clusions: The high proportion of cases with unknown exposure underlines the need to explore new tools and sourcesto ascertain asbestos exposure. An ad hoe survey in textile industries showed exposure to asbestos to be wide/y spreadin this industry.

RIASSUNTO

MESOTHELIO\Lo\ A\'O ASBESTOS EXPOSURE l\' LOMBARDY 355

della casistica totale) sono i casi di mesotelioma maligno certo, 63 (12%) probabili e 33 (6%) possibili mesoteliomi.

21 erano mesoteliomi peritoneali. I tassi standardizzati per et nell'anno 2000 erano 3,7 e 1,4per 100.000 resi-denti rispettivamente per i maschi e lefemmine. L'esposizione occupazionale ad asbesto stata accertata per il 71 %

dei casi tm i maschi e i126% nelle femmine, mentre risultata ignota nel 11% e 27% rispettivamente. I principali

settori lavomtivi coinvolti sono l'edilizia, la metallurgia e la metalmeccanica; una elevata e inaspettata proporzio-

ne di casi stata osservata in donne lavomtrici nella industria tessile non-amianto. stata compiuta una indaginead hoc in tale settore che ha permesso di identificare diverse fonti di esposizione ad amianto nel settore tessile. L'alta

p7'oporzione di casi con esposizione tuttora ignota evidenzia la necessit di trovare nuovi strumenti efonti per l'ac-

certamento delle esposizioni di interesse.

The "Lombardy Mesothelioma Registry" was

established in January 2000 and comprises the Re-gional Operational Cemre of the ltalian National

Registry. The Registry collects all new incidem

cases ofMalignam Mesothelioma (MM), with frst

diagnosis after J anuar)' 2000, occurring in residemsof the Lombard)' Region.

MESOTHELIOMA REGISTRY PROCEDURES

The main departments of each Lombardy hospi-

tal report mesothelioma cases to the RegistI}' di-

rectl)' or through local sciemific institutions which

have already implememed collection of cases in the

past, for example, in the provinces of Brescia, Berg-amo, Cremona and l\1amo\'a. For each case, all

available clinical records are collected and reviewed,

including radiological examinations, histology re-

pom, and disease history, so that a panel composed

of pneumologists, oncologists, and pathologists ma)'

revise the diagnoses. According to standardized cri-

teria set up by the national registI}' (2), diagnoses

are categorized as certain, probable or possible,

based on the availability of histology, immuno-his-

tochemistry assays, and radiological examinations.

Evaluation of asbestos exposure is based on infor-

mation collected through a standardized question-

naire administered by trained interviewers to the

subject or next-of-kin. The information collected is

then discussed with an industri al hygienist, occupa-

tional health physicians, and an occupational epi-

demiologist to evaluate asbestos exposure in the

workplace and in environmental senings.

Case ascertainmem completeness is \'crified us-

ing other sources. Hospiral discharge records and

death certificates coded as 163 according to theICD (Imernational Classification of Diseases) are

obtained from the Lombardy regio n along with the

list of cases compensated by the National Insur-

ance Institute. A link is made with the Registry'sdatabase to idemifv undetected cases for which a

search for clinical documemation is then imple-

memed, and the usual procedures are followed to

conflrm diagnosis and ascertain exposure.

CASE DESCRIPTION A..i"iDDISCUSSION

Case completeness was verified for the years

2000- 2001 following the procedures describedabove. Abour 3000 records were extracted from the

regional database, corresponding to 625 subjects

with a discharge diagnosis of possible pleural tu-mour. After the collection and revision of clinical

records, it was clear that 106 cases had already beenidentified b)' the Registr)', another 106 were non-cases, 93 were prevalem cases. The number of cases

confirmed but not reported to the Registry was

134, equall)' distributed over the two years; these

have been included in the Registry database.

Our of 512 possible cases reviewed by the Reg-

istr;' in the first two years of activity (2000-2001),307 (60%) were judged as "certain" MM, 63 (12%)were probable MIVl, and 33 (5.8%) possible MM;

whereas the diagnosis \Vas not confirmed in 109subjects (21%). As expected, most of the cases(94%) were pleural mesothelioma; only 21 wereperitoneal cases. Descriptive results are given for

certain and probable cases onl)'.

Histological diagnosis \Vas available for 93% of

the cases (361). The most frequent histological

356

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"

,.

types were epithelial (216 cases), followed bybiphasic (66 cases) and tbrous mesothelioma (32cases); a small proportion of cases (30) \Vas detnedas mesothelioma not otherwise specited.

67% of the cases were interviewed directly, in29% of the cases the interview was administered to

relatives. No interview was available for 13 subjects(4%).

Case distribution by age and gender (figure 1)showed a higher proportion of cases among maleswith a 2:1 male/female ratio. Founeen cases oc-

curred in relatively young subjects, less than 45years old. This group of young cases was mainlycharacterized by environmental exposure to as-bestos at a young age (almost half the cases) or un-known exposure. Three cases lived in the Broniarea, weli known for being poliuted by a local as-bestos-cement factory. Only 1 subject had occupa-tional exposure as a plumber.

Age standardized incidence rates were calculatedusing the Italian population in 1991 as Standardand applying the direct method. Results are pre-sented for the year 2000 in which data coliectionand interviews were completed. In figure 2 stan-dardized rates for pleural mesothelioma includingalI diagnoses (certain, probable and possible) are

100 --:

90 -:

80 -

70 -

60 --

50 -

40 -

30 -

20

10

O

reponed separately for males and females and com-pared with the 1997 National Registry rates (4).The Lombardy rate for males was 3.7 per 100.000inhabitants and 1,4 for females. Both were some-

what higher than the national rates reflecting mor-tality data patterns (3). Rates by province did notdepan significantly from the regional rates. Mostof them were based on a very small number of cas-es and prevented any further detailed analysis ac-cording to occupational sectors located in the area.

The evaluation of asbestos exposure derivedfrom information coliected through the standard-ized questionnaire produced different results formales and females.

For males, the major source of exposure was re-lated to occupational activities (71%), 3% had envi-ronmental exposure, and for 11% of the cases, ex-posure was unknown, meaning that, based on theavailable information and current knowledge, wecannot exclude asbestos exposure.

The picture for females was quite different: only26% had occupational exposures, and a similar pro-portion (27%) of cases had unknown exposure. Inaddition, the proponion of cases that had not beenexposed (20%) was higher than in males. About10% had environmental exposure.

98

a Mi~F

35-44 45-54 55-64 65-74 75+

Figure 1 - Case distribution by age and gender (certain and probable cases, 2000-2001)

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~---------------MESOTHEUO:-'L\ A:\'D .-\SBESTOS EXPOSURE I?\ LO:-'1BARDY

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