1494PRisk of lung cancer following pulmonary tuberculosis: A nationwide population-based cohort study, South Korea

Background: Some epidemiologic studies on lung cancer have reported findings that suggest the possibility of association between lung disease and lung cancer. The association of pulmonary tuberculosis (TB) and lung cancer has attracted attention for several years and has remained controversial. Therefore, we investigated that the relationship between pulmonary TB and lung cancer by considering the time of TB diagnosis in this study. Methods: This study was used the National Health Insurance Service – National Sample Cohort in South Korea. Patients with pulmonary TB diagnostic codes and treated with anti-tuberculosis in adults over 20 years of age were defined as pulmonary TB patients. It was monitored the incidence of lung cancer after diagnosis of active pulmonary TB. We compared 3,776 patients with pulmonary TB and 18,880 controls matched for sex and age from 2003 to 2013. Multivariate Cox proportional hazard model was used to calculate the adjusted hazard ratio of lung cancer after adjusting for sex, age, house income, smoking status. The incidences of lung cancer were compared according to duration time after TB infection by calculating the incidence rates ratio (IRR). Results: During the study period, 194 patients were diagnosed with lung cancer. A total of 86 lung cancer patients were diagnosed in 3,776 pulmonary TB patients and 108 patients were diagnosed in 18,880 control group. The IRR in TB group was the higher at 12.26 within 1 year and 3.33 at 1 year to less than 4 years after TB infection compared with the control group. There was a higher risk of lung cancer in pulmonary TB patients compared to control group (HR, 4.18; 95% CI, 3.15-5.56). The risk of lung cancer after pulmonary TB was HR 9.85 (95% CI, 4.57-21.23), 7.14 (95% CI, 3.63-14.05), 3.32 (95% CI, 2.12-5.19) and 2.57(95% CI, 1.40-4.72) respectively under 50s, 50s, 60s and 70s above. As the age increased, HR of lung cancer decreased after diagnosis of pulmonary TB, gradually. Conclusions: Pulmonary tuberculosis is a risk factor for lung cancer. In patients with pulmonary TB, it may be considered the co-existence of lung cancer and be necessary to carefully observe the occurrence of lung cancer for a certain period of time after diagnosis of pulmonary TB, especially in younger patients. Legal entity responsible for the study: Seon-Sook Han. Funding: Has not received any funding. Disclosure: All authors have declared no conflicts of interest.