How have we diagnosed early-stage lung cancer without radiographic screening? A contemporary single-center experience.

Background: The National Lung Screening Trial (NLST), which demonstrated a reduction in lung cancer mortality, may result in widespread computed tomography (CT)-based screening of select populations. How early-stage lung cancer has been diagnosed without screening, and what proportion of these cases would be captured by a screening program modeled on the NLST, is not currently known. We therefore evaluated current patterns of early-stage lung cancer presentation.

Methodology/principal Findings: We performed a single-institution retrospective analysis of patients diagnosed with stage I-II non-small cell lung cancer (NSCLC) from 2000-2009. Associations between patient and imaging characteristics were assessed using univariate and multivariate analyses. A total of 412 patients met criteria for analysis. Among those with available reason for initial imaging, the reason was symptoms in 51%, follow-up of other conditions in 43%, and screening in 6%. Reason for imaging was associated with race (P<0.001), insurance type (P=0.005), and disease stage (P<0.001). Type of initial imaging was associated with reason for imaging (P<0.001), year (chest x-ray 67% in 2000-2004 vs. 49% in 2005-2009; P<0.001), and disease stage (P = 0.005). Among patients with available quantified smoking history, 48% were age 55-74 years and smoked 30-plus pack-years, therefore meeting NLST entry criteria.

Conclusions/significance: Symptoms remain a dominant but declining reason for detection of early-stage NSCLC. The proportion of cases detected initially by CT scan without antecedent chest x-ray has increased considerably. Because as few as half of cases meet NLST eligibility criteria, clinicians should remain aware of the diverse circumstances of early-stage lung cancer presentation to expedite therapy.