Occupational exposure to asbestos and cholangiocarcinoma: findings from an explorative case-control analysis

Mattioli, Stefano

Wednesday, March 21, 2012: 15:35

Isla Mujeres 1 (Cancun Center)

Stefano Mattioli, Department of Internal Medicine, Geriatrics and Nephrology, University Of Bologna, Bologna, Italy

Andrea Farioli, Department of Internal Medicine, Geriatrics and Nephrology, University of Bologna, Bologna, Italy

Stefania Di Girolamo, Department of Hematology and Oncological Sciences “L. e A. Seragnoli”, University di Bologna, Bologna, Italy

Stefano Casciardi, Department of Internal Medicine, Geriatrics and Nephrology, University of Bologna, Bologna, Italy

Francesco Draicchio, Department of Hematology and Oncological Sciences “L. e A. Seragnoli”, University of Bologna, Bologna, Italy

Francesco Violante, Department of Internal Medicine, Geriatrics and Nephrology, University of Bologna, Bologna, Italy

Guido Biasco, Department of Hematology and Oncological Sciences “L. e A. Seragnoli”, University of Bologna, Bologna, Italy

Giovanni Brandi, Department of Hematology and Oncological Sciences “L. e A. Seragnoli”, University of Bologna, Bologna, Italy

Introduction
Alongside to respiratory cancers, exposure to asbestos has been associated with gastrointestinal cancers. An association between exposure to amphibole fibers and their presence in hepatic tissue has been reported. We conducted a case-control analysis to explore the association between occupational exposure to asbestos and cholangiocarcinoma.

Methods
We used historical data from 155 consecutive patients referred to our center for diagnosis and treatment of cholangiocarcinoma in 2007-2011 (69 affected by Intrahepatic Cholangiocarcinoma (ICC) and 86 by Extrahepatic Cholangiocarcinoma (ECC)). When feasible, cases were individually matched (ratio up to 1:4) by calendar period of birth (5-year interval), sex and provenience to historical population controls (originally sampled to study other occupational diseases, not related to asbestos). Occupational exposure to asbestos was assessed by industrial hygienists considering job titles and calendar period: we classified as exposed subjects that have held at least one potentially exposed job. Separate conditional logistic regression models were conducted for ICC and ECC, adjusting for smoking status and socioeconomic class.

Results
We matched 149 controls (median birth year: 1947; males: 56%) to 41 cases of ICC (median birth year:1946; males: 56%) and 212 controls (median birth year:1945; males: 48%) to 59 cases of ECC (median birth year: 1945; males 51%); 47 cases were not matched mainly due to provenience. We found an increased risk of ICC in workers exposed to asbestos (adjusted OR 4.81, 95%CI 1.73-13.33); conversely, no clear evidence of increased risk was found for ECC (adjusted OR 2.09, 95%CI 0.83-5.27). Sensitivity analysis conducted using only patients from our city district (conducted to minimize referral bias) produced confirmatory figures.

Discussion
Findings from our exploratory study support the hypothesis that ICC could arise from chronic irritation and inflammation caused by deposition of asbestos fibers. Well-designed case-control studies are needed to investigate the putative occupational determinants of this rare cancer.

A1612 Occupational exposure to asbestos and cholangiocarcinoma: findings from an explorative case-control analysis