Central Tumor Location at Chest CT Is an Adverse Prognostic Factor for Disease-Free Survival of Node-Negative Early-Stage Lung Adenocarcinomas

Background The prognostic value of primary tumor location in the central lung is unclear because of heterogeneity in definitions of central lung cancer (CLC). Purpose To (a) validate the prognostic value of two recently proposed definitions of CLC by using a method designed to offset the shortcomings of existing evidence and (b) investigate the prognostic implications of a quantitative definition of CLC at chest CT. Materials and Methods Patients with pathologic stage T1a-bN0M0 lung adenocarcinomas resected between 2009 and 2015 at a single tertiary care center were retrospectively identified. The primary end point was disease-free survival. The associations of multiple definitions of central tumor location with survival were evaluated by using multivariable Cox regression. Time-dependent discrimination measures and interreader agreement were assessed for each definition. Results A total of 436 patients (median age, 62 years [interquartile range, 55-69 years]; 245 women) were evaluated. Tumor location at CT in the inner one-third of the lung defined by concentric lines arising from the hilum was adversely associated with survival (five events among 34 patients with CLC and 27 events among 402 patients with peripheral lung cancer; adjusted hazard ratio, 2.90 [95% CI: 1.06, 7.96; P = .04]) and showed moderate interreader agreement (Cohen κ = 0.52 [95% CI: 0.37, 0.68]). Quantitatively determined location in the inner two-thirds of the lung was also an independent prognostic factor (16 events among 130 patients with CLC and 16 events among 306 patients with peripheral lung cancer; adjusted hazard ratio, 2.77 [95% CI: 1.36, 5.65]; P = .005), with higher interreader agreement (Cohen κ = 0.86 [95% CI: 0.80, 0.91]; P < .001). The quantification-based definition exhibited higher time-dependent sensitivity (48.2% [14.27/29.61; 95% CI: 28.8, 67.6] vs 15.1% [4.47/29.61; 95% CI: 1.3, 28.9]; P < .001). Conclusion Central lung cancer at chest CT, defined qualitatively or quantitatively, is an independent adverse prognostic factor in patients with node-negative, early-stage lung adenocarcinomas. The quantification-based approach has advantages in terms of time-dependent sensitivity and reproducibility. © RSNA, 2021 Online supplemental material is available for this article. See also the editorial by Wandtke and Hobbs in this issue.