Table 4.

Multivariate analysis of predictive factors for lymph node metastasis (preoperative model)

Predictive factors	Pulmonary LN a metastasis (pN1+)	Mediastinal LN a metastasis (pN2+)	Any LN a metastasis (pN+) e
Central localization	P = 0.002 b OR = 2.9 c CI = 1.5–5.6 d	P = 0.06 OR2.0 CI = 0.9–4.1	P = 0.005 OR = 2.6 CI = 1.3–5.1
Increased tumor size	P = 0.043 OR = 1.2 CI = 1.0–1.3	P = 0.040 OR = 1.2 CI = 1.0–1.4	P = 0.005 OR = 2.5 CI = 1.3–4.4

^aLN Lymph node, ^bP P-Value, ^cOR Odds ratio, CI 95%, ^dCI Confidence interval, ^e Patients were divided in two groups according to tumor size (> 3 cm and ≤ 3 cm)