Background: Lung Cancer (LC) screening with low dose chest computed tomography (LDCT) in smokers reduces LC mortality. Patients with Obstructive Lung Disease (OLD) are at high risk for LC. The potential effect of LC screening in this population is unknown.
Objective: To determine if screening with LDCT reduces LC mortality in smokers with spirometrically defined OLD.
Methods: The National Lung Screening Trial-American College of Radiology Imaging Network (NLST-ACRIN) study included 13,831 subjects (55-74 years of age with >= 30 pack-year history of smoking) that had a baseline spirometry. Randomly assigned to LDCT or Chest X-ray, all had 3 annual rounds of screening. LC mortality was compared between the LDCT and chest X-ray arms during the 1st year and at 6 years of follow up. Landmark analysis explored LC mortality differences between arms after the first year.
Results: From the 4584 subjects with OLD (FEV1/FVC <0.7), 152 (3.3%) died from LC. Multivariable analysis showed that screening trended to decrease LC mortality at 6 years (HR, 95%CI: 0.75, 0.55-1.04, p = 0.09). During the 1st year no differences were found between arms (p = 0.65). However, after this year, LDCT significantly decreased LC mortality (HR, 95%CI: 0.63, 0.44-0.91, p = 0.01). The number needed to screen to avoid one LC death in these subjects was 108 while in those without OLD was 218.
Conclusions: LC screening with LDCT in smokers with spirometrically diagnosed OLD, showed a trend to reduce lung cancer mortality but a study with a larger number of patients and with a more robust design would be needed to confirm these findings.