Table 3 Cox Proportional-hazards Regression Model for Recurrence-free Survival and Overall Survival in Patients with IMA ≤ 2 cm (n = 266) and > 2 to 3 cm of Shanghai Pulmonary Hospital Cohort (n = 137)

IMA ≤ 2 cm

 Age (> 65 vs. ≤ 65)

0.564

0.304

 Gender (male vs. female)

0.181

0.689

 Smoking (current or ex vs. non-smoker)

0.456

0.286

 Cardiovascular disease (present vs. absent)

0.444

0.278

 Diabetes mellitus (present vs. absent)

0.177

0.649

 %predicted FEV1 (> 80% vs. ≤ 80%)

0.475

0.695

 CEA (> 5 ng/ml vs. ≤ 5 ng/ml)

0.141

0.511

 VPI (present vs. absent)

0.468

0.714

 Tumor location (upper and middle vs. lower)

0.465

0.741

 Surgical procedure (limited resection vs. lobectomy)

0.953

0.552

 Lymph node status (positive vs. negative)

< 0.001

6.981 (2.433–20.034)

< 0.001

0.017

4.296 (1.291–14.297)

0.020

IMA > 2.1 to 3 cm

 Age (> 65 vs. ≤ 65)

0.767

0.880

 Gender (male vs. female)

0.648

0.137

 Smoking (current or ex vs. non-smoker)

0.887

0.330

 Cardiovascular disease (present vs. absent)

0.422

0.417

 Diabetes mellitus (present vs. absent)

0.971

0.857

 %predicted FEV1 (> 80% vs. ≤ 80%)

0.906

0.352

 CEA (> 5 ng/ml vs. ≤ 5 ng/ml)

0.263

0.253

 VPI (present vs. absent)

0.845

0.777

 Tumor location (upper and middle vs. lower)

0.664

0.881

 Surgical procedure (limited resection vs. lobectomy)

0.010

2.417 (1.157–5.049)

0.019

0.122

 Lymph node status (positive vs. negative)

0.002

3.444 (1.492–7.949)

0.004

0.005

4.059 (1.495–11.025)

0.005