Table 2 Cox Proportional-hazards Regression Model for Recurrence-free Survival and Overall Survival in Patients with IMA ≤ 3 cm of Shanghai Pulmonary Hospital Cohort (n = 403)

Age (> 65 vs. ≤ 65)

0.597

0.663

Gender (male vs. female)

0.378

0.138

Smoking (current or ex vs. non-smoker)

0.404

0.756

Tumor size (2.1–3 cm vs. ≤ 2 cm)

0.008

1.286 (1.019–1.621)

0.033

0.110

Cardiovascular disease (present vs. absent)

0.397

0.211

Diabetes mellitus (present vs. absent)

0.149

0.622

%predicted FEV1 (> 80% vs. ≤ 80%)

0.885

0.267

CEA (> 5 ng/ml vs. ≤ 5 ng/ml)

0.091

1.344 (0.782–2.309)

0.284

0.246

VPI (present vs. absent)

0.319

0.622

Tumor location (upper and middle vs. lower)

0.378

0.870

Surgical procedure (limited resection vs. lobectomy)

0.170

0.239

Lymph node status (positive vs. negative)

< 0.001

4.204 (2.126–8.315)

< 0.001

< 0.001

4.497 (2.106–9.603)

< 0.001