Is There a Prognostic Difference Between Stage IIIA Subgroups in Lung Cancer?

Abstract

Treatment of stage IIIA lung cancer remains controversial because it includes a very heterogeneous group of patients. The purpose of our study was to compare survival between stage IIIA subsets and to externally validate our results with another center's database. Patients with completely resected stage IIIA/B lung cancer were retrospectively analyzed. There were 424 patients with stage IIIA and 82 patients with stage IIIB (T3/4 N2) (study cohort). Stage IIIA was divided into 2 subsets according to the tumor localization and tumor size (T3 N1-T4 N0/1, IIIA-T group; n = 308) and the extension of nodal disease (T1/2 N2, IIIA-N2 group; n = 116). The study cohort results were used to create a model for stage IIIA patients, which was validated with another center's database (validation cohort). The multivariate analyses showed age, stage IIIB, and pN2 were independent negative prognostic factors (P < .0001). Survival at 5 years was 51.3% (median, 64 months) for patients in the IIIA-T group and was 25.7% (median, 31 months) in the IIIA-N2 patients (hazard ratio, 1.834; P < .0001). There was no statistical difference in survival between the IIIA-N2 and stage IIIB groups (25.7% vs 25.3%, P = .442). The created model was performed on patients in the validation cohort as a model IIIA-T (T3 N1-T4 N0/1, n = 139) and model IIIA-N2 (T1/2 N2, n = 104). Model IIIA-T patients had a statistically better survival rate than model IIIA-N2 patients (median, 62 months vs 37 months; hazard ratio, 1.707, P < 0.001). There is a prognostic difference between stage IIIA subgroups in lung cancer patients who undergo surgical treatment.