Table 5 Subgroup analyses according to tumor location

 Non-adjusted

0.60 (0.54, 0.67) < 0.001

0.48 (0.35, 0.66) < 0.001

0.81 (0.57, 1.17) 0.264

  Traditional regression model

0.58 (0.51, 0.66) < 0.001

0.55 (0.39, 0.76) < 0.001

0.54 (0.35, 0.86) 0.009

  2SRI IV model

0.43 (0.12, 1.48) 0.181

0.39 (0.01, 18.80) 0.637

1.57 (0.01, 217.96) 0.858

 Non-adjusted

0.58 (0.52, 0.66) < 0.001

0.48 (0.34, 0.66) < 0.001

0.85 (0.58, 1.24) 0.392

  Traditional regression model

0.57 (0.50, 0.64) < 0.001

0.53 (0.37, 0.75) < 0.001

0.53 (0.32, 0.87) 0.013

  2SRI IV model

0.72 (0.20, 2.62) 0.614

0.44 (0.01, 24.44) 0.689

0.90 (0.00, 203.30) 0.970