Clinical impact of updated cardiopulmonary exercise testing guidelines in lung cancer surgery

Objectives Cardiopulmonary exercise testing (CPET) has been central to preoperative risk assessment before lung cancer surgery since the European Respiratory Society (ERS)/European Society of Thoracic Surgeons (ESTS) guideline was introduced in 2009. The guideline was recently updated, including incorporation of ventilatory efficiency (ventilation (VE)/carbon dioxide elimination (VCO ₂) slope) and revised thresholds for risk stratification. We aimed to determine how application of the updated ERS/ESTS CPET algorithm from 2025 reclassifies physiological risk compared with the 2009 version and to assess the clinical consequences in terms of major postoperative complications across risk categories.Methods We retrospectively analysed 506 patients who underwent CPET during evaluation for suspected or confirmed lung cancer (2008–2020). Risk categorisation was applied according to both 2009 and 2025 ERS/ESTS CPET algorithms. For patients proceeding to lobectomy (n=138), we compared discrimination and predictive values for major pulmonary complications or death within 30 days.Results Risk group distribution shifted markedly: low/intermediate/high risk changed from 20%/78%/2% (2009) to 42%/33%/25% (2025). Among those classified as high risk by the 2025 algorithm (n=127), 91% were newly identified, primarily due to VE/VCO ₂-slope >40. In the lobectomy subset, area under the curve was 0.61 for the 2025 algorithm versus 0.57 for 2009 (p=0.998).Conclusion The 2025 ERS/ESTS guideline substantially redistributes patients across risk categories, largely driven by incorporation of VE/VCO ₂ slope. Overall discrimination was modest and did not differ from the 2009 algorithm. Although patients classified as high risk according to the 2025 algorithm had the highest observed event rate, selection for surgery under the previous guideline limits conclusions regarding the prognostic validity of the expanded high-risk category.