Evaluation of maximum standardized uptake value at fluorine-18 fluorodeoxyglucose positron emission tomography as a complementary T factor in the eighth edition of lung cancer stage classification

Prognostic value of CT-defined ground-glass opacity in early-stage lung adenocarcinomas: a single-center study and meta-analysis

OBJECTIVES

The prognostic value of ground-glass opacity at preoperative chest CT scans in early-stage lung adenocarcinomas is a matter of debate. We aimed to clarify the existing evidence through a single-center, retrospective cohort study and to quantitatively summarize the body of literature by conducting a meta-analysis.

METHODS

In a retrospective cohort study, patients with clinical stage I lung adenocarcinoma were identified, and the prognostic value of ground-glass opacity was analyzed using multivariable Cox regression. Commercial artificial intelligence software was adopted as the second reader for the presence of ground-glass opacity. The primary end points were freedom from recurrence (FFR) and lung cancer-specific survival (LCSS). In a meta-analysis, we systematically searched Embase and OVID-MEDLINE up to December 30, 2021, for the studies based on the eighth-edition staging system. The pooled hazard ratios (HRs) of solid nodules (i.e., absence of ground-glass opacity) for various end points were calculated with a multi-level random effects model.

RESULTS

In a cohort of 612 patients, solid nodules were associated with worse outcomes for FFR (adjusted HR, 1.98; 95% CI: 1.17-3.51; p = 0.01) and LCSS (adjusted HR, 1.937; 95% CI: 1.002-4.065; p = 0.049). The artificial intelligence assessment and multiple sensitivity analyses revealed consistent results. The meta-analysis included 13 studies with 12,080 patients. The pooled HR of solid nodules was 2.13 (95% CI: 1.69-2.67; I2 = 30.4%) for overall survival, 2.45 (95% CI: 1.52-3.95; I2 = 0.0%) for FFR, and 2.50 (95% CI: 1.28-4.91; I2 = 30.6%) for recurrence-free survival.

CONCLUSIONS

The absence of ground-glass opacity in early-stage lung adenocarcinomas is associated with worse postoperative survival.

CLINICAL RELEVANCE STATEMENT

Early-stage lung adenocarcinomas manifesting as solid nodules at preoperative chest CT, which indicates the absence of ground-glass opacity, were associated with poor postoperative survival. There is room for improvement of the clinical T categorization in the next edition staging system.

KEY POINTS

• In a retrospective study of 612 patients with stage I lung adenocarcinoma, solid nodules were associated with shorter freedom from recurrence (adjusted hazard ratio [HR], 1.98; p = 0.01) and lung cancer-specific survival (adjusted HR, 1.937; p = 0.049). • Artificial intelligence-assessed solid nodules also showed worse prognosis (adjusted HR for freedom from recurrence, 1.94 [p = 0.01]; adjusted HR for lung cancer-specific survival, 1.93 [p = 0.04]). • In meta-analyses, the solid nodules were associated with shorter freedom from recurrence (HR, 2.45) and shorter overall survival (HR, 2.13).

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.