Table 2 Univariable and multivariable Cox regression analysis comparing no surgery with surgery for the OS of AJCC 8th T4N0-3M0 EC patients

Surgery

 No

1

1

 Yes

0.435 (0.382–0.496)

 < 0.001

0.492 (0.427–0.567)

 < 0.001

Year of diagnosis

 2004–2009

1

 2010–2015

0.967 (0.878–1.065)

0.497

Age

  < 65 years old

1

1

  >  = 65 years old

1.243 (1.130–1.368)

 < 0.001

1.102 (0.998–1.217)

0.055

Sex

 Male

1

 Female

1.039 (0.928–1.163)

0.504

Race

 White

1

1

 Black

1.375 (1.217–1.555)

 < 0.001

1.060 (0.925–1.214)

0.401

 Other/unknown

0.925 (0.767–1.115)

0.412

0.809 (0.668–0.980)

0.031

Primary site

 Upper third

1

1

 Middle third

1.190 (1.015–1.396)

0.033

1.283 (1.090–1.510)

0.003

 Lower third

0.857 (0.747–0.982)

0.027

1.105 (0.938–1.301)

0.233

 Unknown

1.260 (1.072–1.481)

0.005

1.198 (1.012–1.417)

0.035

Histology

 Adenocarcinoma

1

1

 Squamous cell carcinoma

1.408 (1.274–1.556)

 < 0.001

1.347 (1.177–1.542)

 < 0.001

 Other

1.671 (1.383–2.021)

 < 0.001

1.376 (1.128–1.678)

0.002

Differentiation

 Grade I

1

1

 Grade II

1.175 (0.911–1.517)

0.214

1.187 (0.918–1.535)

0.191

 Grade III/IV

1.365 (1.060–1.756)

0.016

1.464 (1.134–1.890)

0.003

 Unknown

1.296 (0.995–1.688)

0.055

1.182 (0.904–1.545)

0.221

T stage

 T4a

1

1

 T4b

1.543 (1.344–1.772)

 < 0.001

1.193 (1.031–1.381)

0.018

 T4, NOS

1.219 (1.079–1.378)

0.002

1.103 (0.962–1.265)

0.159

N stage

 N0

1

1

 N1

0.861 (0.763–0.972)

0.015

1.116 (0.980–1.271)

0.098

 N2

0.834 (0.681–1.022)

0.08

1.084 (0.879–1.337)

0.452

 N3

1.136 (0.875–1.476)

0.339

1.717 (1.310–2.250)

 < 0.001

 N1–3, NOS

1.071 (0.947–1.212)

0.274

1.166 (1.024–1.328)

0.021

Radiotherapy

 No/unknown

1

1

 Yes

0.433 (0.391–0.480)

 < 0.001

0.573 (0.508–0.646)

 < 0.001

Chemotherapy

 No/unknown

1

1

 Yes

0.368 (0.332–0.408)

 < 0.001

0.497 (0.439–0.562)

 < 0.001