Survival of patients with non-small cell lung cancer according to lymph node disease: single pN1 vs multiple pN1 vs single unsuspected pN2.

Purpose: This study was designed to describe the characteristics and survival of NSCLC patients treated with surgery and single pN1 disease, multiple pN1, and single unsuspected pN2.

Methods: In 2005-2009, we treated 378 lung cancer patients with surgery with radical intent; 152 cases were pN1 or pN2. We excluded patients with neoadjuvant treatment, incomplete resection, incomplete lymph node dissection, metastasis, cN2 disease, multiple pN2, SCLC, and lack of PET-CT. All patients were staged with TNM 2010. We included 72 patients: 21 single pN1, 26 multiple pN1, and 25 single unsuspected pN2. Statistical analysis included descriptive statistics, chi-square test, Kaplan-Meier, log-rank test, and Cox proportional hazard model.

Results: The sample included 62 men (86 %) and 10 women (14 %), mean age 64 ± 9 years. The three subgroups did not show statistically significant differences in the main characteristics. Adjuvant treatment was performed in 56 patients (78 %). The 5 year overall survival (OS) for single pN1 was 73 %; for multiple pN1, 34 %; and for single unsuspected pN2, 25 % (P = 0.15). The mean OS for single pN1 was 63 ± 6 months; median OS for multiple pN1 was 45 (range, 42-48) months and for single pN2 was 54 (range, 32-77) months. Multivariate analysis found the following negative prognostic factors of OS: for single pN1, age, female sex, and microscopic intratumoral lymphatic and vascular invasion; for multiple pN1, ≤10 lymph nodes resected.

Conclusions: Patients with single pN1 had better OS than patients with multiple pN1. Patients with single unsuspected pN2 had OS similar to that of multiple pN1.