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N. De Klerk
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P2.05 - Poster Session/ Prevention and Tobacco Control (ID 216)
- Event: WCLC 2015
- Type: Poster
- Track: Prevention and Tobacco Control
- Presentations: 1
- Moderators:
- Coordinates: 9/08/2015, 09:30 - 17:00, Exhibit Hall (Hall B+C)
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P2.05-011 - Presence of Pleural Plaques and/or Asbestosis and the Risk of Lung Cancer in a Crocidolite Asbestos Exposed Population from Western Australia (ID 889)
09:30 - 09:30 | Author(s): N. De Klerk
- Abstract
Background:
Asbestos exposure is associated with dose-dependent risk of benign pleural disease, lung cancer and mesothelioma. While an association between asbestosis and lung cancer (even after adjustment for asbestos exposure) is well established [Reid et al, OEM 2005], the link between lung cancer and the presence of pleural plaque remains controversial.
Methods:
We followed 2,218 subjects exposed to crocidolite asbestos as miners (n=1286) or mine township residents, monitored with annual review, chest radiography (CXR) and outcome linkage to national cancer and mortality registry data over a 25-year period. Subjects were followed up from the date of their latest x-ray taken a year or more before the date of death, cancer incidence, or end of follow-up. Hazard ratios for lung cancer were estimated by Cox regression, with age as the underlying matching time variable, for sex, tobacco smoking, asbestos exposure estimates (time since first exposure and fibre/ml years), International Labour Organisation CXR readings for asbestosis (defined as profusion score > 1/0) and presence (and extent) of pleural plaques.
Results:
Mean age at follow up was 60.6 years, 1,575 (71%) were male, 328 (14.8%) had any pleural plaque and 359 (16.2%) had asbestosis. 103 (4.64%) lung cancers were recorded. 1568 (70.7%) were ever-smokers with a mean tobacco exposure of 39.3 pack years.
Table 1. Hazard ratios for diagnosis of lung cancerHR Lower 95% CI Upper 95% CI p-value Log (yrs) SFE 1.77 .60 5.22 0.298 Ever smoker 18.1 2.5 132 0.004 Pack years 1.009 1.005 1.01 <0.0005 Female 0.75 .38 1.48 0.408 Profusion: 0/1 1.88 1.14 3.10 0.013 1/0 1.64 0.87 3.07 0.124 1/1 3.64 1.83 7.24 <0.0005 1/2 6.10 2.03 18.3 0.001 > 2/1 2.18 0.64 7.49 0.215 Log f/ml yrs 1.223 1.076 1.390 0.002 Any PP 1.048 0.601 1.826 0.869 SFE = since first exposure; f/ml = fibres / ml; PP = pleural plaque; HR = hazard ratio; CI = confidence interval
Conclusion:
In our population, the presence of pleural plaque is not associated with an increased risk of subsequent lung cancer. This is contrary to a recent report that had smaller numbers of lung cancer and used death certificates [Pairon, AJRCCM, 2014]. As we have demonstrated previously, the presence of asbestosis and cumulative asbestos exposure both contribute to increased subsequent lung cancer risk, although previous tobacco smoke exposure remains the strongest risk factor.
