Table 2 Cox proportional hazards model for overall survival in elderly patients with resectable proximal gastric carcinoma who underwent surgery from NCDB database

Age (per 1 SD)

1.04 (1.02–1.06)

<0.001

1.10 (1.05–1.15)

<0.001

 Female

Ref.

Ref.

 Male

1.21 (1.08–1.36)

0.001

1.03 (0.77–1.37)

0.87

Race

0.15

 White

Ref.

–

 Black

0.98 (0.76–1.26)

0.86

–

 Asian

0.70 (0.49–1.00)

0.05

–

CDCI Score

<0.001

0.01

 0

Ref.

Ref.

 1

1.32 (1.17–1.50)

<0.001

1.34 (0.99–1.81)

0.06

 ≥ 2

1.79 (1.50–2.12)

<0.001

1.72 (1.17–2.52)

0.006

Tumor size

<0.001

0.33

 ≤ 2 cm

Ref.

Ref.

 2-4 cm

1.56 (1.33–1.82)

<0.001

1.38 (0.91–2.09)

0.13

 4-6 cm

2.03 (1.72–2.40)

<0.001

1.15 (0.71–1.85)

0.57

 >6 cm

2.31 (1.94–2.76)

<0.001

1.05 (0.63–1.75)

0.86

Differentiation grade

<0.001

0.45

 Well

Ref.

Ref.

 Moderately

1.24 (1.04–1.62)

0.02

1.01 (0.58–1.75)

0.98

 Poorly

1.95 (1.57–2.42)

<0.001

1.25 (0.72–2.17)

0.42

 Undifferentiated

1.72 (1.13–2.61)

0.01

0.92 (0.33–2.58)

0.88

Pathologic TNM stage

<0.001

<0.001

 Stage 0-I

Ref.

Ref.

 Stage II

1.75 (1.52–2.01)

<0.001

1.41 (0.96–2.06)

0.08

 Stage III

2.76 (2.43–3.14)

<0.001

3.61 (2.47–5.26)

<0.001

 Negative

Ref.

Ref.

 Positive

1.75 (1.40–2.20)

<0.001

0.95 (0.69–1.32)

0.77

Type of surgery

<0.001

0.01

 Subtotal gastrectomy

Ref.

Ref.

 Total gastrectomy

1.14 (0.97–1.32)

0.10

1.20 (0.85–1.69)

0.30

 Gastrectomy with other organs

1.63 (1.33–2.00)

<0.001

1.88 (1.22–2.91)

0.004

 Local excision

0.61 (0.52–0.70)

<0.001

0.64 (0.38–1.08)

0.10

 Negative

Ref.

Ref.

 Positive

1.83 (1.57–2.12)

<0.001

1.68 (1.17–2.41)

0.01

Number of LNs examined (per 1 SD)

1.01 (1.01–1.02)

<0.001

0.99 (0.97–1.00)

0.10

Treatment facility

<0.001

0.14

 AR-program

Ref.

Ref.

 INC-program

1.21 (1.01–1.45)

0.04

0.99 (0.61–1.60)

0.96

 CCC-program

1.33 (1.18–1.49)

<0.001

1.36 (1.02–1.81)

0.03

 CC-program

1.55 (1.25–1.92)

<0.001

1.36 (0.80–2.32)

0.26

 No

Ref.

–

 Yes

0.94 (0.82–1.08)

0.36

–

 No

Ref.

–

 Yes

0.97 (0.84–1.13)

0.72

–

 Upfront surgery

Ref.

–

 neoadjuvant therapy

1.05 (0.77–1.43)

0.76

–