Epidemiology in Asbestos Cases
Yes, there remain epidemiology questions even after all these years . Pharyngeal Cancer
. Laryngeal Cancer
. Esophageal Cancer
. Stomach Cancer
. Colorectal Cancer A Valuable Resource re Other Cancers
Asbestos: Selected Cancers (NAS) • Pre-Trial Hearings
. Articles read and relied upon . Dr. Schwartz and Colon Cancer Laryngeal Cancer
. Largely related to drinking and smoking, like esophageal cancer.
. NAS Study does see a link between asbestos exposure and laryngeal cancer --- BUT . Related to asbestos --- 1 < RR <2 --- disease causation is more ambiguous
Laryngeal Cancer Laryngeal Cancer Risk 1< RR <2 Present Absent Assuming RR=1.5 Exposure 6 4 Control 4 6
No disease
Disease w/ Asbestos
Disease w/ OR w/o Asbestos
Exposure Control
Among the 6 cases in exposure group, 4 cases will occur even without asbestos exposure Laryngeal Cancer
4/6 in Asbestos group will have Laryngeal cancer with or without Asbestos
No disease Due to Asbestos Disease w/ Asbestos w/ or w/o Asbestos Disease w/ OR w/o Asbestos
Exposure Control
Attributable Risk = (6-4)/6 = 33.3% --- <50% CONCLUSION
Chances of developing Laryngeal Cancer due to Asbestos v. Other Causes = (6-4)/6 = 33.3%
<50%
Lung Cancer
. Many questions, many studies: . Smoking . Synergy between smoking and asbestos . Absence of asbestosis . Presence of plaques Smoking
. Lung cancer without smoking? . Only Selikoff & Hammond/Selikoff.
. Many dangers from smoking including second hand smoke.
. RR lung cancer from smoking: . CPS I = 11.35 . CPS II = 22.36
Need for Asbestosis
. Heuper (1955)
. Kipen, Pulmonary Fibrosis in Asbestos Insulation Workers with Lung Cancer…, (1987) . Asbestosis found in 100% of cases.
. Helsinki -- Many opinions Mesothelioma Epidemiology
Is there anything left to learn about mesothelioma causation?
Can Chrysotile Asbestos Cause Mesothelioma at < 300 f-ml/yrs? . Liddell (1996) said “NO”. . Auto mechanic studies . Plaintiff claims: . Vianna (case report) . Studies from China . The Balangero Mines studies . Piolatto (1990) . Mirabelli (2008) . Balangeroite
Mesothelioma Epi Questions
. What levels of chrysotile have been shown epidemiologically to cause mesothelioma? . What about peritoneal meso?
. What low levels of asbestos generally have been epidemiologically shown to cause mesothelioma?
. Is there any epidemiology to support synergy between amphiboles and chrysotile? (Hammar idea)
A Tale of Two Mines
Thetford Mines - Quebec Balangero Mine - Italy Thorough cohort study over • Small cohort study many years supplemented by some case reports
The Balangero Mine
Piolatto study Mirabelli report Can Any Asbestos Cause Mesothelioma at < 1 f/cc-yr?
. No Epidemiology has shown that . Case reports - Vianna . Hillerdal (1999) – anecdotes. Synergy Between Chrysotile and Amphiboles?
. Dr. Hammar contention . Hessel, Mesothelioma Among Brake Mechanics…., (2004) – refutes the contention.