Percent predicted peak oxygen uptake is superior to weight-indexed peak oxygen uptake in risk stratification before lung cancer lobectomy

<bold>Objective:</bold> To improve preoperative risk stratification in lung cancer lobectomy by identifying and comparing optimal thresholds for peak oxygen uptake (VO2peak) presented as weight-indexed and percent of predicted values, respectively. <bold>Methods:</bold> Data from patients scheduled for cancer lobectomy who underwent preoperative cardiopulmonary exercise testing during years 2008-2020 were included. Measured VO2peak was indexed by body mass (ml/kg/min) and compared to two reference equations (Wasserman-Hansen and SHIP-study). By receiver operating characteristic analysis, a lower 90% sensitivity and an upper 90% specificity threshold were determined for each measure, in relation to the outcome any major complication or death within 30 days. For each measure, based on these thresholds, patients were categorized as low, intermediate or high risk. The frequency of complications was compared between groups using Chi2. <bold>Results:</bold> The frequency of complications differed significantly between the proposed low, intermediate and high-risk groups when using % predicted SHIP (5%, 21%, 35%, p=0.007) or % predicted Wasserman-Hansen (5%, 25%, 35%, p=0.002), but not when using the weight-indexed VO2peak groups (7%, 23%, 15%, p=0.08). Non-significant differences were found using the threshold <15 ml/kg/min, (p=0.34). <bold>Conclusions:</bold> Weight-indexed VO2peak was of less use as a marker of risk at the lower range of exercise capacity whereas % predicted VO2peak was associated with a continuously increasing risk of major complications, also at the lower end of exercise capacity. As identifying subjects with high risk of complications, % of predicted VO2peak may be preferable.