Surgical outcomes after initial surgery for clinical single-station N2 non-small-cell lung cancer

Single-station N2 (Stage IIIA) non-small-cell lung cancer has been reported to have a relatively favorable prognosis after surgery. However, most previous studies examined surgical outcomes in N2 disease by pathologic nodal status but not by clinical nodal status. The objective of this study was to clarify the surgical outcomes in clinical single-station N2 non-small-cell lung cancer patients.

A total of 125 consecutive patients with clinical single-station N2 non-small-cell lung cancer were treated in our institution between 1992 and 2008. Among them, 97 (78%) patients underwent thoracotomy, and were included in this retrospective study. We defined clinical single-station N2 node as a node measuring 1-2 cm in a single mediastinal station observed on contrast-enhanced computed tomography. The median follow-up period was 5.9 years (range, 1.8-12.6).

Eighty-eight (91%) patients underwent lung resection. Of them, 17 (19%) had true (pathologic) single-station N2 disease. Twenty-eight (32%) had pathologic multistation N2 and 43 (49%) had pN0-1 disease with favorable prognoses. The overall survival of the clinical single-station N2/pathologic N2 patients after initial surgery was unsatisfactory with a 5-year overall survival of 23.6%, but their prognoses were heterogeneous. True single-station pathologic N2 status (hazard ratio = 0.35, P = 0.008) and negative subcarinal node status (hazard ratio = 0.34, P = 0.022) were independent favorable prognostic factors after initial resection for clinical single-station N2/ pathologic N2 patients. The patients with both factors revealed a relatively favorable 5-year overall survival of 43.8%.

Clinical single-station N2 status does not always correspond with pathologic true N2 status. From a prognostic point of view, initial surgery for clinical single-station N2 patients is indicated if their true single-station N2 status and negative subcarinal involvement are preoperatively confirmed.