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

Abstract

BACKGROUND

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.

METHODS

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 (T3/4N2) (study cohort). Stage IIIA was divided into two subsets according to the tumor localization / tumor size (T3N1-T4N0/1, IIIA-T group; n=308) and the extension of nodal disease (T1/2N2, IIIA-N2 group; n=116). According to the study cohort results, a model for stage IIIA patients was created. It was validated with another center's database (validation cohort).

RESULTS

In the multivariate analyses, age, stage IIIB and pN2 were all independent negative prognostic factors (p<0.0001). Five-year survival for patients in the IIIA-T group was 51.3% (median 64 months), whereas it was 25.7% (median 31 months) in the IIIA-N2 patients (HR=1.834, p<0.0001). There was no statistical difference in regard to the survival between the IIIA-N2 and stage IIIB groups (25.7% versus 25.3%, p=0.442). The created model was performed on patients in the validation cohort as a model IIIA-T (T3N1-T4N0/1, n=139), and model IIIA-N2 (T1/2N2, n=104). Model IIIA-T patients had a statistically better survival rate than model IIIA-N2 patients (median 62 months versus 37 months, HR=1.707, p=0.0007).

CONCLUSIONS

There is a prognostic difference between stage IIIA subgroups in lung cancer patients who undergo surgical treatment.