Mizrahi D, Fardell JE, Cohn RJ, et al. - Given a higher likelihood of cardiovascular disease among childhood cancer survivors compared with siblings, researchers sought to develop a simple algorithm to predict cardiorespiratory fitness and to establish cut-points identifying survivors' cardiovascular fitness health-risk zones. Two hundred sixty-two childhood cancer survivors (8-18 years old, ≥ 1-year posttreatment) underwent gold-standard cardiorespiratory fitness assessment (Cardiopulmonary Exercise Test (CPET; VO_2max)) and 6-minute walk test (6MWT). They included 199 participants (aged 13·7±2·7 years, 8·5±3·5 years posttreatment). Findings revealed a strong positive correlation between VO_2max and 6MWT distance. Inclusion of 6MWT distance, waist-to-height ratio, age, and gender was done in the regression algorithm to predict VO_2max. For FITNESSGRAM's ‘health-risk’ fitness zone, the cut-point was 39·8 ml/kg/min (males: AUC = 0·88), and 33·5 ml/kg/min (females: AUC = 0·82). The proposed algorithm was identified as reasonably predicting cardiorespiratory fitness for childhood cancer survivors, using inexpensive measures. They identified this algorithm as clinically useful, particularly when CPET is unavailable. The algorithm may allow clinicians to recognize survivors below the cut-points with increased cardiovascular disease risk, to monitor and refer for tailored interventions with exercise specialists.