Vol. 70, Iss. 7, July 2013
Cholangiocarcinoma among offset colour proof-printing workers exposed to 1,2-dichloropropane and/or dichloromethane
Riassunto
Objectives The present study was conducted to investigate the relationship between occupational chemical exposure and incidence of cholangiocarcinoma among workers in the offset colour proof-printing section of a small printing company in Osaka, Japan.
Methods We identified 51 men who had worked in the proof-printing room, and 11 men who had worked in the front room for at least 1 year between 1991 and 2006. We interviewed them about the chemicals they used, and estimated their levels of exposure to chemicals. We also investigated the medical records of 11 cholangiocarcinoma patients, and calculated the standardised mortality ratio (SMR) from 1991 to 2011.
Results Workers used 1,2-dichloropropane (1,2-DCP) from approximately 1985 to 2006, and dichloromethane (DCM) from approximately 1985 to 1997/1998. Exposure concentrations were estimated to be 100–670 ppm for 1,2-DCP and 80–540 ppm for DCM among the proof-printing workers. All 11 patients were pathologically diagnosed with cholangiocarcinoma. Ages at diagnosis were 25–45 years, and ages at death were 27–46 years among the six deceased individuals. The primary cancer site was the intrahepatic bile duct for five patients, and the extrahepatic bile ducts for six. All patients were exposed to 1,2-DCP for 7–17 years and diagnosed with cholangiocarcinoma 7–20 years after their first exposure. Ten patients were also exposed to DCM for 1–13 years. The SMR for cholangiocarcinoma was 2900 (expected deaths: 0.00204, 95% CI 1100 to 6400) for all workers combined.
Conclusions These findings suggest that 1,2-DCP and/or DCM may cause cholangiocarcinoma in humans.
Commento
Il rischio chimico nell'industria tipografica è correlato all’utilizzo di una vasta gamma di composti, principalmente rappresentati da pigmenti organici ed inorganici, olii, resine, cere, adesivi e solventi.
Già nel 1996, la IARC ha classificato il rischio chimico professionale presente nei processi di stampaggio come possibile cancerogeno per l'uomo, basandosi principalmente sulle evidenze di recenti studi di letteratura sul tema.
In occasione del congresso annuale della Società Giapponese di Medicina del Lavoro (maggio 2012), Kumagai e colleghi hanno riportato, in un loro studio, la presenza di cinque casi di colangiocarcinoma in una azienda tipografica di 40 lavoratori a Osaka, stimandone un incidenza di circa 600 volte superiore alla media nazionale Giapponese. I risultati ottenuti sono stati in parte confermati anche da altri autori nella letteratura sia europea che statunitense.
Nel presente studio, Kumagai e colleghi si propongono di indagare le relazioni esistenti tra l’esposizione chimica professionale e l’incidenza di cancerogenesi epatica in questa tipologia di lavoratori.