Central Airway Obstruction in Lung Cancer Associated With Poor Survival

Patients with prevalent central airway obstruction (CAO) at diagnosis with lung cancer may have higher mortality rates than patients without CAO, according to a study published in BMJ Open Respiratory Research.

In this cohort review, researchers conducted an audit of new primary lung cancer diagnoses between November 1, 2014, and November 30, 2015 (N=342). Patients with CAO at presentation were followed over a 4-year period until November 30, 2018. CAO was defined as an identifiable narrowing of the central airways due to lung cancer on cross-sectional imaging, and the degree was defined as the ratio of the diameter of the narrowest section of the obstructed airway to the nearest proximal normal segment of the tracheobronchial tree.

CAO prevalence on index computed tomography (CT) scans was 45/342 (13%; 95% CI, 10%-17%). Therapeutic bronchoscopy was performed in 8/31 eligible patients (26%). The overall mortality rate during the follow-up period was 1.52 per 1000 person days (95% CI, 1.35-1.71). Mortality rates for patients with and without CAO on index CT scans were 4.67 (95%, 3.48-6.28) per 1000 person days and 1.35 (95% CI, 1.19-1.53) per 1000 person days, respectively (P <.001 for both). 

Limitations of this study included being conducted at a single site; however, gender, age, stage, and histological confirmation and distribution of the patients were similar to UK National Lung Cancer Audit data, suggesting that the results are generalizable. Another potential limitation is that only one interventionalist reviewed CT scans to define CAO, without the presence of a blinded second reader for all scans. Additionally, the absence of bronchoscopy as well as other missing data could have resulted in the underestimation of disease prevalence.

“We found CAO and high disease stage were independently associated with an increased mortality rate,” the researchers wrote. “The median survival of patients with CAO in our audit was 3 months, but 25% of patients lived >8 months. A recent study of patients with and without CAO, found no difference in the proportion that died or median survival time in the two groups.”

Reference

Daneshvar C, Falconer WE, Ahmed M, et al. Prevalence and outcome of central airway obstruction in patients with lung cancer [published online September 24, 2019]. BMJ Open Respir Res. doi:10.1136/bmjresp-2019-000429