Inhaled corticosteroids may prevent lung cancer in asthma patients
I-Jen Wang1, Wen-Miin Liang2, Trong-Neng Wu3, Wilfried J.J. Karmaus4, Jiin-Chyr Hsu5
1 Department of Pediatrics, Taipei Hospital, Ministry of Health and Welfare; School of Medicine, National Yang-Ming University, Taipei; College of Public Health, China Medical University, Taichung, Taiwan
2 Graduate Institute of Biostatistics, China Medical University, Taichung, Taiwan
3 Asia University, Taichung, Taiwan
4 Division of Epidemiology, Biostatistics, and Environmental Health, School of Public Health, University of Memphis, Memphis, TN, USA
5 Department of Respiratory Medicine, Taipei Hospital, Ministry of Health and Welfare, Taipei, Taiwan
Dr. I-Jen Wang
Department of Pediatrics, Taipei Hospital, Ministry of Health and Welfare, 127 Su-Yuan Road, Hsin-Chuang District, New Taipei City 242
BACKGROUND: It is unclear whether inhaled corticosteroids (ICS) have chemopreventive effect on lung cancer (LC) development in humans. We investigated the association between the ICS use in asthma patients and the risk of LC.
METHODS: We conducted a nationwide, population-based retrospective cohort study using the National Health Insurance database. We identified 4210 asthmatics who were initially free of LC and regularly used ICS between 2001 and 2005 and 37,228 asthmatics without regular ICS use. Patients with documented history of tobacco use were excluded from the analyses. Asthmatics were categorized into a mild and a severe asthma group. Each patient was tracked until the end of 2010 to identify incident cases of LC. Cox proportional hazards models were used to evaluate the effect of ICS on the risk of LC, further stratifying by asthma severity and comorbidities.
RESULTS: During follow-up, we identified 747 incident cases of LC diagnosed in the asthma cohort. Compared with severe asthmatics without regular ICS use, the risk of LC for those with mild asthma with regular ICS use was lower (adjusted hazard ratio = 0.42, 95% confidence interval = 0.31–0.56, P < 0.0001). The risk of LC was calculated among the following rankings of risk severe asthma without regular ICS use, low severity without regular ICS, high severity with regular ICS, and low severity with regular ICS group showed a decreasing trend of LC incidence (P = 0.041). Analyses stratified by comorbidities revealed that the protective effect of ICS was assessed with better precision and more pronounced in those with renal diseases, stroke, and hyperlipidemia.
CONCLUSIONS: For patients with asthma, regular ICS use might have a protective effect against LC. Further studies are required to assess this potential association from both immunohistopathological and clinical aspects.