Temporal trends in outcomes following sublobar and lobar resections for small (≤ 2 cm) non-small cell lung cancers--a Surveillance Epidemiology End Results database analysis

Abstract

Background: Since the randomized, controlled study that favored lobectomy for resection of stage I non-small cell lung cancers (NSCLCs) by the Lung Cancer Study Group, there have been improvements in staging. The liberal use of computed tomography also may have altered the types of early lung cancer diagnosed. Studies published since then have drawn contradictory conclusions on the benefit of lobectomy over sublobar resections for early-stage NSCLC. We examined the Surveillance Epidemiology End Results database to test our hypothesis that the relationship between extent of resection and outcome has changed since the Lung Cancer Study Group study was published.

Methods: We examined stage I NSCLCs ≤ 2 cm in size over three periods: 1988-1998 (Early), 1999-2004 (Intermediate), and 2005-2008 (Late). For each period, we assessed overall and disease-specific survivals and their associations with the extents of resection, by univariate and multivariate analyses. Sublobar resections in the Early group could not be categorized into segmentectomies and wedge resections because these were not coded separately.

Results: The proportion of NSCLCs ≤ 2 cm increased from 0.98% in 1988 to 2.2% in 2008. Multivariate analyses showed that sublobar resection was inferior to lobectomy in the Early period (hazard ratio [HR], 1.41; 95% confidence interval [CI], 1.21-1.65). This effect decreased in the Intermediate period, in which segmentectomies but not wedge resections were equivalent to lobectomies (wedge versus lobectomy HR, 1.19; 95% CI, 1.01-1.41; segmentectomy versus lobectomy HR, 1.04; 95% CI, 0.8-1.36). The difference disappeared in the Late period, when both wedge resections and segmentectomies were equivalent to lobectomy (wedge versus lobectomy HR, 1.09; 95% CI, 0.79-1.5; segmentectomy versus lobectomy HR, 0.83; 95% CI, 0.47-1.45). Trends for both overall survival and disease-specific survival were identical.

Conclusions: The survival benefit of lobectomy over sublobar resection decreased over the past 2 decades with no discernible difference in the most contemporary cases. These results support reevaluation of lobectomy as the standard of care for small (≤ 2-cm) NSCLCs.