Epidemiology in Asbestos Cases

Yes, there remain epidemiology questions even after all these years . Pharyngeal

. Laryngeal Cancer

. Esophageal Cancer

. Stomach Cancer

. Colorectal Cancer A Valuable Resource re Other

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

. cancer without smoking? . Only Selikoff & Hammond/Selikoff.

. Many dangers from smoking including second hand smoke.

. RR 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 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.