Reconsidering T component of cancer staging for T3/T4 non-small-cell lung cancer with additional nodule

Background: Non-small-cell lung cancer (NSCLC) with additional nodule(s) located in the same lobe or ipsilateral different lobe were designated as T3 and T4, respectively, which was merely defined by anatomical location of additional nodule(s), regardless of other prognostic factors. Methods: A total of 4711 patients with T1-4, N0-2, M0 NSCLC undergoing complete resection were identified between 2009 and 2014, including 145 patients with additional nodule(s) in the same lobe (T3-Add) and 174 patients with additional tumor nodule(s) in ipsilateral different lobe (T4-Add). Overall survival (OS) was compared using multivariable Cox regression models and propensity score matching analysis (PSM). Results: T3-Add patients [T3-Add versus T3, hazard ratio (HR), 0.695; 95% confidence interval (CI), 0.528–0.915; p = 0.009] and comparable OS with T2b patients through multivariable Cox analysis, and further validated by PSM. T4-Add patients carried a wide spectrum of prognosis, and the largest diameter of single tumor was screened out as the most effective indicator for distinguishing prognosis. T4-Add (⩽3 cm) patients had better OS than T4 patients [T4-Add (⩽3 cm) versus T4, HR, 0.629; 95% CI, 0.455–0.869; p = 0.005] and comparable OS with T3 patients. And T4-Add (>3 cm) patients had comparable OS with T4 patients. Conclusion: NSCLC patients with additional nodule(s) in the same lobe and ipsilateral different lobe (maximum tumor diameter ⩽ 3 cm) should be further validated and considered restaging as T2b and T3 in the forthcoming 9th tumor, node, and metastasis staging system.