Table I. Patient characteristics according to age group.

ASA: The American Society of Anesthesiologists; ASA-PS: ASA physical status classification; CEA: carcinoembryonic antigen; CA19-9: carbohydrate antigen 19-9, IQR: interquartile range. *Categorical variables are presented as proportions. Non-normally distributed variables are reported as medians with interquartile ranges. †Categorical data were compared using the chi-square test or Fisher’s exact test. Non-normally distributed data were compared using the Mann-Whitney U-test.