Bronchiectasis increases risk for lung cancer regardless of smoking history

The presence of non-cystic fibrosis bronchiectasis increased risk for lung cancer regardless of smoking status, according to recent findings published in Annals of the American Thoracic Society.

“It has not been well known whether non-cystic fibrosis bronchiectasis is associated with an increased risk of lung cancer independent of smoking history ... because previous studies did not evaluate smoking status in their analyses,” Hayoung Choi, MD, PhD, study investigator and associate professor at Hanyang University College of Medicine in Seoul, South Korea, told Healio. “Taking advantage of having information on smoking status in the Korean National Health Insurance Service data, this study evaluated the impact of smoking status on the relationship between bronchiectasis and lung cancer development.”

The population-based cohort study included 3,858,422 participants from the 2009 National Health Screening Program. Choi and colleagues assessed lung cancer incidence in individuals with (n = 65,305) and without (n = 3,793,117) bronchiectasis, following them until they were diagnosed with lung cancer, died or reached the end of the study period in December 2018.

Participants with bronchiectasis tended to be women (51.2% vs. 45.6%), older (age 60 years, 47.5% vs. 20.4%) and have lower BMIs (23.6 kg/m² ± 3.2 vs. 23.7 kg/m² ± 3.2) than those without bronchiectasis. Furthermore, a greater proportion of the bronchiectasis group were never-smokers (67.4% vs. 60.1%) and had COPD (32.9% vs. 4.5%).

Compared with those without bronchiectasis, those with bronchiectasis had a significantly higher lung cancer incidence (2.1 vs. 0.7 per 1,000 person-years; P < .001).

Results of a model adjusting for potential confounders and accounting for the competing risk for mortality revealed an adjusted hazard ratio of developing lung cancer of 1.22 (95% CI, 1.14-1.3) for those with bronchiectasis.

The risk for lung cancer remained significantly greater among participants with vs. without bronchiectasis independent of smoking status (for never-smokers: adjusted HR = 1.28; 95% CI, 1.17-1.41; for ever-smokers: aHR = 1.26; 95% CI, 1.1-1.44). This association persisted for ever-smokers with 20 or more pack-years of smoking history (aHR = 1.14; 95% CI, 1.03-1.26), but not for those with fewer than 10 pack-years (aHR = 1.23; 95% CI, 0.94-1.61) or 10 to 19 pack-years (aHR = 1.21; 95% CI, 0.97-1.51).

In analyses that looked at the impact of COPD, bronchiectasis did not increase the risk for lung cancer among those with COPD (aHR = 1.06; 95% CI, 0.97-1.16), but did increase the risk for lung cancer in those without COPD (aHR = 1.19; 95% CI, 1.09-1.31).

“The analyses revealed that subjects with bronchiectasis have an increased risk of lung cancer regardless of smoking history,” Choi concluded.