Comparison of lung cancer risk in black-coal miners based on mortality and incidence

Abstract

Background Cancer risk (especially as regards lung cancer) in black-coal miners is mainly analyzed on the basis of mortality. The risk calculated based on mortality may differ from the values based on incidence. The aim of the study was to compare cancer risk in black-coal miners with and without coal workers’ pneumoconiosis (CWP), based on data on mortality and the incidence of lung cancer in the Czech Republic in 1992–2013. Material and Methods The cohort without CWP was composed of 6687 miners, and the cohort with CWP of 3476 miners. Information on the incidence of lung cancer was obtained from the Czech National Oncological Register (NOR), and information on mortality from the National Population Register. The risk of lung cancer incidence was compared with the general male population in the Czech Republic using the standardized incidence ratio (SIR), and the risk of lung cancer mortality using the standardized mortality ratio (SMR), with the 95% CI. Results In miners with CWP, a lower SMR value was found, SMR = 1.70 (95% CI: 1.41–2.04), compared with the SIR value, SIR = 2.01 (95% CI: 1.70–2.36). In miners without CWP, this was opposite, the value of SIR = 0.81 (95% CI: 0.69–0.94) was lower than the value of SMR = 0.83 (95% CI: 0.70–0.98). In miners without CWP, 17 cases of lung cancer (out of 176 cases in total) were not registered in NOR. In miners with CWP, the share of not registered cases was significantly lower (p = 0.018), and it was represented by 3% of not registered lung cancer cases, out of 156 cases with the diagnosis of lung cancer. Conclusions In spite of the difference between SIR and SMR, the results of both indicators were consistent with the resulting relationship between the lung cancer risk and CWP. Med Pr. 2020;71(5):513–8

Keywords

• lung cancer
• aging
• standardized mortality ratio
• standardized incidence ratio
• misleading results
• coal workers’ pneumoconiosis