Variability in defining T1N0 non-small cell lung cancer impacts locoregional failure and survival

Abstract

Background: Locoregional recurrence can occur despite complete anatomic resection of T1N0 non-small cell lung cancer. That may be the result of incomplete resection or inaccurate staging. We assessed the impact of extent of nodal staging on the rate of locoregional failure and patient survival.

Methods: The records of 742 patients undergoing lobectomy, bilobectomy, or pneumonectomy for non-small cell lung cancer from 1996 to 2006 were reviewed. Operative reports and pathology reports were reviewed for the number of lymph nodes and the anatomic nodal stations examined. The Kaplan-Meier method was applied to analyze recurrence-free survival.

Results: A total of 119 patients with pathologically staged Ia lung cancer were identified. Histology type included 61% (n = 73) adenocarcinoma, 27% (n = 32) squamous cell cancer, and 12% (n = 14) other. Median age was 65 years (range, 34 to 88). Mean follow-up duration was 40 months (median 47; range, 1 to 121). Locoregional recurrence occurred in 20% (n = 18). The N2 nodal stations were examined in 94% (n = 112). At least one defined N1 nodal station was examined in 70% (n = 83). Station undefined N1 nodes were examined in 27% (n = 32), and no N1 nodes were examined in 3% (n = 4). Median number of N1 lymph nodes analyzed was 5 (range, 0 to 18). The locoregional recurrence rate was 14% (12 of 83) for patients with a defined N1 station node versus 31% (11 of 36) for patients in whom there were undefined N1 nodes (p = 0.03). Similar differences were seen in disease-free survival, 78.2% versus 62.6%, respectively (p = 0.06).

Conclusions: Despite anatomic resection of stage Ia lung cancer and uniform analysis of N2 nodal stations, a high rate of locoregional recurrence occurs. Imprecise staging of N1 lymph nodes may contribute to the understaging and undertreatment of patients with early stage lung cancer.