Table 2 Cox proportional hazard regression analysis of recurrence-free survival in patients diagnosed with stage IA micropapillary non-predominant lung adenocarcinoma with a micropapillary component > 5%

Age

0.992

0.950–1.036

0.727

Sex

 Female

Ref

Ref

 Male

0.340

0.133–0.871

0.025

0.441

0.146–1.332

0.146

Smoking history

 Non-smoker

Ref

 Smoker

0.876

0.323–2.376

0.795

Surgical procedure

 Open

Ref

 VATS

0.616

0.227–1.671

0.341

Resection range

 Sublobar resection

Ref

Ref

 Lobectomy

0.346

0.141–0.850

0.021

0.071

0.020–0.251

 < 0.001

Surgical side

 Left

Ref

 Right

1.067

0.456–2.498

0.881

Number of LN dissected

1.007

0.951–1.067

0.804

Tumor size

2.214

1.073–4.570

0.032

2.929

1.171–7.330

0.022

Micropapillary component

1.034

0.988–1.083

0.152

Papillary component

1.002

0.989–1.016

0.760

Solid component

0.987

0.957–1.019

0.432

Acinar component

0.995

0.982–1.007

0.397

Lepidic component

1.005

0.992–1.019

0.442

Lymphovascular invasion

 No

Ref

 Yes

0.581

0.078–4.329

0.597

Spread through air spaces

 No

Ref

 Yes

0.837

0.247–2.837

0.775

pTNM stage

 IA1

Ref

 IA2

6990.189

0–6.386E + 80

0.922

 IA3

12,719.830

0–1.162E + 81

0.917

Adjuvant chemotherapy

 No

Ref

Ref

 Yes

0.325

0.127–0.832

0.019

0.122

0.037–0.403

0.001