Cardiopulmonary exercise testing in patients with non-small cell lung cancer: trust the V^˙ O_2peak?

Maximal oxygen consumption (V^˙ O_2max) is the most frequently used variable to determine postoperative risk in patients with non-small cell lung cancer (NSCLC), however patients frequently cannot provide the necessary maximum effort to ensure the validity of the V^˙ O₂ measurements. The aim of this observational study was to assess exercise-limiting factors and the rate of achievement of the currently recommended maximality criteria in patients with NSCLC who had been routinely referred for cardiopulmonary exercise testing (CPET) to assess their postoperative risk.

Patient data, including peak exercise variables and markers used to designate the exercise test as maximal, were retrospectively analysed from 203 preoperative CPET assessments that were performed at Rouen University Hospital from January 2014 until July 2019.

Ventilatory limitation was the most common physiological cause of exercise cessation. A total of 62 patients (or 30.5%) achieved either one, or no, markers of maximality. The mean duration of the incremental phase (after the 3-minute warm-up) was 5.1±2 minutes.

About 30% of the patients in this study did not generate maximum effort during CPET. As a result, it is likely that their V^˙ O_2peak was underestimated and that their post-operative risk was overestimated. It is therefore important to incorporate strategies to verify V^˙ O_2peak results for patients with _values close to the risk threshold.