Investigation of the non-small cell lung cancer patients with bronchus involvements: A population-based study

We aimed to explore the prognostic differences among T1-4N0-2M0 non-small cell lung cancer (NSCLC) patients with bronchus involvements and to validate the T category of these patients in an external cohort.

Univariable and multivariable Cox analysis was performed to determine the prognostic factors. Kaplan-Meier method with a log-rank test was used to compare overall survival differences between groups. Propensity score matching method was used to minimize the bias caused by the imbalanced covariates between groups.

A total of 169 390 eligible T1-4N0-2M0 NSCLC cases were included. There were 2354, 3367, 1638, 75, 87 585, 42 056, 19 246, and 13 069 cases in the group of superficial tumors of any size with invasive component limited to bronchial wall (T1-bronchus), tumors involving main stem bronchus ≥2 cm from carina (T2-main bronchus [≥2 cm]), tumors involving main stem bronchus <2 cm from carina (T2-main bronchus [<2 cm]), tumors with carina invasion (T4-carina), T1, T2, T3, and T4, respectively. Multivariable Cox analysis indicated that T1-bronchus patients had the best prognosis; T2-main bronchus (≥2 cm) and T2-main bronchus (<2 cm) patients had similar prognosis both in the entire cohort and in several subgroups. Survival curves showed that T1-bronchus and T1 patients had similar survival rates; the survivals of T2-main bronchus patients regardless of the distance from carina were comparable to those of T2 patients, and the survivals of T4-carina patients were also similar to those of T4 patients.

Our results validated and supported the current T category for the patients with bronchus involvements, which might provide certain reference value for the revisions of T category in the next version of the tumor-node-metastasis stage classification.