P181 Does The Degree Of Occupational Asbestos Exposure Affect The Outcome Of Radical Surgery For Malignant Pleural Mesothelioma?

Introduction Malignant Pleural Mesothelioma (MPM) is associated with variable exposure to asbestos and a spectrum of prognosis which may be extended by radical surgery. Proportional mortality ratios have been used in the past to estimate the risk of developing mesothelioma, and more recently specific occupational risk groups have been described.1 We aimed to determine whether those at highest risk of developing mesothelioma by virtue of working in high exposure occupations also fared worse after radical surgery for mesothelioma. Methods Case notes were reviewed for all patients undergoing radical surgery for MPM between 1999 and 2014. Prior asbestos exposure had been determined by histories taken by the multidisciplinary team. Patients were separated into one of 8 groups, using modified versions of the categories proposed by Rake et al. in 2009.1 Comparative outcome was assessed for each group. Results History of asbestos exposure was available for 262 patients. Thirteen patients were excluded from further analysis having died in hospital. Of the remaining 249 patients, 84.3% were male, and median age was 62 years (range 14–81 years). The only significant intergroup difference was gender, with more females in the low risk and no exposure groups (p = 0.021). However, in our cohort of surgically treated patients, gender had no effect on survival (p = 0.476). There was a significant difference in survival between the low risk group and the high and medium risk groups combined (24.2 vs 14.5 months p = 0.031). Survival was similar between those with known asbestos exposure and those who reported no asbestos exposure; 14.7 vs 15.2 months p = 0.573. Conclusion This is the first study to demonstrate that those patients who worked in occupations at highest risk of developing mesothelioma also have the worst comparative survival from radical surgery. The causation remains a topic for further research. It is also of note that patients with no reported asbestos exposure had an unexpectedly poor survival. The importance of a careful occupational history of asbestos exposure is emphasised. Reference Rake C, Gilham C, Hatch J, Darnton A, Hodgson J, Peto J. Occupational, domestic and environmental mesothelioma risks in the British population: a case-control study. Br J Cancer. 2009 Apr 7;100(7):1175–83 Abstract P181 Table 1 Exposure Group(Rake et al) Asbestos exposure n Median survival(months) p Risk Group Median survival(months) p 1 Any non-construction high-risk job 60