Document rpmb4Yq9J3okr3YKbjoJy7E07

FILE NAME Brakes BRK DATE 2012 DOC BRK212 DOCUMENT DESCRIPTION Journal Article - Regulatory Toxicology and Pharmacology Letter to the Editor Regulatory Toxicology and Pharmacology xxx 2012 XXX Contents lists available at SciVerse ScienceDirect Regulatory Toxicology and Pharmacology journal homepage www.elsevier.com/locate/yrtph Letter concerning the paper by Finley and colleagues dx.doi.org/ j.yrtph.2012.05.015 Dear Dr. Gori Having yesterday completed an invited review of an asbestos paper for Regulatory Toxicology and Pharmacol- ogy I think that it is appropriate for me to comment on the paper by Finley and colleagues entitled Malignant Pleural Mesothelioma in U.S. Automotive Mechanics Reported vs Expected Number of dx.doi.org/10.1016/j.yrtph.2012.05.015 Cases from the number 1975 to 2007 recently published online http The authors compared of malignant pleural mesothelioma MPM cases re- ported in the U.S. literature among auto mechanics between 1975-2007 to an expected value derived from estimated numbers of current and former auto mechanics A total of 106 cases categorized as mesothelioma or malignant neoplasm of the pleura were found in the literature Using background incidence rates for asbestos MPM of 2 and 3 cases per million individuals per year they esti- mated that a range of 278-515 cases of MPM respectively would have occurred in current or former auto mechanics from 1975 to 2007. They concluded that their findings are consistent with the numerous epidemiology studies that have found no increased risk of MPM in auto mechanics It is my opinion that the analysis of Finley and colleagues is fatally flawed and that their results and conclusion are not credi- ble The fundamental epidemiologic error is that the cases and controls were not derived from the same sampling frame and are thus not comparable The cases were derived from reports in the medical literature of mesothelioma among automotive mechanics the person at risk PYR from which the ex- pected number of cases was calculated were computed from a population based sample of all automotive mechanics working in the United States The authors have thus compared the experience of that unknown fraction of mechanics whose disease was re- ported in the literature to an expectation based upon the entire Table 1 Sensitivity analysis of observed vs expected cases of mesothelioma among US auto mechanics in which the reporting rate of cases in the literature is varied Finley et al found 106 cases They estimated that 500 would be expected Publication rate 0.1 % % 10 25 50 100 Actual incidence 1000 ^ 106 = 106,000 100 x 106 = 10,600 20^ 21=2 210 20 10 ^ 106 = 1060 ^ 424 ^ 21 = 22 12 106 Expected 500 500 500 500 500 500 500 SMR 200 20 4 2 1 04 02 population of US mechanics To provide a valid comparison the authors should have compared the total number of cases of mesothelioma among US auto mechanics unknown to the expectation computed from the PYR of all US auto mechanics or compared the number of cases of mesothelioma reported in the literature to the expectation computed from the PYR of those auto mechanics described in the literature There are enormous challenges to both these approaches but the authors have failed in their attempt to compute a credible estimate from the hybrid approach It will be clear to all physicians and epidemiologists that the a number of cases of any condition reported in the literature repre- sent only a small fraction of those actually occurring For example I was asked in August 2008 by plaintiff's attorney to review a case of mesothelioma in an auto mechanic Since that time I have been asked to review an additional 28 cases of mesothelioma in friction workers Not a single one of these 29 cases has been re- ported in the medical literature Finley reports that he or some of his colleagues have been retained by defense attorneys in asbestos litigation I estimate that there is a less than 0.1 probability that any of the friction cases that they consulted on have been reported in the literature From our combined experience the best estimate is that no cases of mesothelioma among auto mechanics have been reported in the literature The report by Finley and colleagues provides evidence that this estimate of a % reporting rate based on the experience of two groups of consultants is incorrect It is appropriate then to undertake a sensitivity analysis of how the relative risk of mesothelioma among auto mechanics would vary according to the reporting rate of mesothelioma cases in the literature Table 1 shows how the mortality rate ratio or SMR would vary according to the proportion of mesothelioma cases among mechanics that are actually reported in the literature The Table shows that the reporting rate would have to be somewhat over 25 for the SMR for mesotheli- oma to equal 1. At higher rates of reporting the SMR falls below 1 and reaches 0.2 at the level of reporting used by Finley and colleagues I leave it to you and your readers to guess as to the proportion of cases of mesothelioma among US auto mechanics that are re- ported in the literature and to extract your personal estimate of the SMR from the Table My own guess is that less than 1 in 20 cases of MPM occurring among brake mechanics are reported in the literature This would correspond to an SMR for pleural meso- of thelioma 4 or higher An increased risk of in auto mechan- MPM ics is consistent with the deposition and retention of Canadian asbestos fibers in the lungs of these workers Finkelstein 2008 Conflict of interest The author has worked as a consultant to plaintiff's lawyers in asbestos litigation 0273-2300 see front matter '2012 Elsevier Inc All rights reserved http dx.doi.org dx.doi.org 10.1016 j.yrtph.2012.08 016 2 Letter to the Editor Regulatory Toxicology and Pharmacology xxx 2012 xxx Reference Finkelstein M. 2008. Asbestos fibre concentrations in the lungs of brake workers another look Ann Occup Hyg 52 455-461 Murray M. Finkelstein Department of Family and Community Medicine University of Toronto Gluskin Family Granovsky Gluskin Family Medicine Sinai Hospital Medicine Centre Mt Sinai Hospital 60 Murray Street 4th Floor Toronto Ontario Canada M5T 3L9 Fax +1 416 736 8543 mail address murray.finkelstein@utoronto.ca Available online xxxx