Characteristics of included studies.

The score of each study was allocated from 0 to 9 according on the modified Newcastle–Ottawa Scale and showed in Study quality. Comparability:1 = age, 2 = gender, 3 = BMI, 4 = clinical stage, 5 = tumor side, 6 = tumor position, 7 = tumor size, 8 = previous abdominal surgery history, 9 = ASA score, NA = data not available. Variables:1 = operating time, 2 = warm ischemic time, 3 = estimated blood loss, 4 = hospital stay, 5 = postoperative SCr level, 6 = complications, 7 = Positive margin. Study quality: The score of each study was allocated from 0 to 9 according on the modified Newcastle-Ottawa scale.