ICS use tied to lower lung cancer risk in COPD patients
Use inhaled corticosteroids (ICSs) in patients with chronic obstructive pulmonary disease (COPD) was associated with a significantly reduced risk of developing lung cancer compared with patients without ICS exposure, according to data from the CORE* study.
“Results showed that if you had COPD and consistently used a steroid inhaler, your chances of getting lung cancer were between 25 per cent and 30 per cent lower compared to people who took other treatments,” said principal investigator Professor Larry Lynd of the University of British Columbia in Vancouver, Canada.
Among the 39,676 patients (mean age 70.7 years, 53 percent female) with COPD included in the study, 994 patients (2.5 percent) had lung cancer during the follow-up period. [Eur Respir J 2019; doi:10.1183/13993003.01257-2018]
After adjusting for various potential confounders, a multivariate analysis revealed that ICS exposure was associated with a 30 percent reduced risk of lung cancer (hazard ratio [HR] 0.70, 95 percent confidence interval [CI], 0.61–0.80).
The association remained regardless of the definition of ICS exposure used, be it time-dependent ICS exposure (HR, 0.70; p<0.001), cumulative dose (HR, 0.83; p=0.0201) or years of use (HR, 0.89; p<0.001), or the recency-weighted approach.
In particular, lung cancer risk was reduced by 26 percent per weighted year (HR, 0.74, 95 percent [CI], 0.66–0.82) when using a recency-weighted duration of use exposure metric, and by 43 percent per gram of ICS use (HR, 0.57, 95 percent CI, 0.43–0.74) based on a recency-weighted cumulative dose metric.
According to the researchers, the recency-weighted duration of use method “accounts for the duration of use of ICS while simultaneously accounting for the timing of the exposure relative to the lung cancer diagnosis.”
Furthermore, analyses of lung cancer histology showed similar results of a protective effect of ICS. Based on the recency-weighted duration of use approach, ICS exposure was associated with a reduced risk of both NSCLC (HR, 0.76; p<0.001) and SCLC (HR, 0.56; p=0.002).
Although the mechanism behind the association remains elusive, previous evidence has indicated that persistent inflammation may be an important contributor to the pathogenesis of lung cancer. “[Thus,] long-term ICS use may have salutary effects in reducing the risk of lung cancer in COPD patients,” suggested the researchers.
Further work needed
“The appropriate use of ICS in COPD patients is often debated and not all patients might benefit from the use of ICS. The clinical benefits and risk of use in an individual patient must be weighed by the physician,” advised Lynd and co-authors.
“This study, however, indicates that potential benefits may accrue from ICS use in COPD patients in terms of reduced lung cancer risk and that sustained use may be associated with reduced risk of lung cancer,” they added.
“More work is clearly needed to understand the exact nature of the relationship between lung cancer risks and steroid use," said Lynd. "Over the next few months, we will find out which COPD patients would benefit the most from inhaled steroids.”