External validation of postoperative nausea and vomiting risk scores in patients with liver cancer: A single-centre prospective cohort study

•The type of surgery had a significant effect on postoperative nausea and vomiting (PONV); prediction models should not be recommended for clinical use among new and different patients before external validity is established.•The discrimination and calibration power of the Apfel score and the Koivuranta score to predict PONV in patients with liver cancer revealed unsatisfactory predictive abilities.•Disease-specific risk factors should be taken into account when updating or developing PONV risk stratification instruments used in the patients with liver cancer.