Preoperative Exercise Vo₂ Measurement for Lung Resection Candidates: Results of Cancer and Leukemia Group B Protocol 9238

Introduction

A stepwise approach to the functional assessment of lung resection candidates is widely accepted, and this approach incorporates the measurement of exercise peak Vo₂ when spirometry and radionuclear studies suggest medical inoperability. A new functional operability (FO) algorithm incorporates peak exercise Vo₂ earlier in the preoperative assessment to determine which patients require preoperative radionuclear studies. This algorithm has not been studied in a multicenter study.

Methods

The CALGB (Cancer and Leukemia Group B) performed a prospective multi-institutional study to investigate the use of primary exercise Vo₂ measurement for the prediction of surgical risk. Patients with known or suspected resectable non-small cell lung cancer (NSCLC) were eligible. Exercise testing including measurement of peak oxygen uptake (Vo₂), spirometry, and single breath diffusion capacity (DLCO) was performed on each patient. Nuclear perfusion scans were obtained on selected high-risk patients. After surgery, morbidity and mortality data were collected and correlated with preoperative data. Mortality and morbidity were retrospectively compared by algorithm-based risk groups.

Results

Three hundred forty-six patients with suspected lung cancer from nine institutions underwent thoracotomy with or without resection; 57 study patients did not undergo thoracotomy. Patients who underwent surgery had a median survival time of 30.9 months, whereas patients who did not undergo surgery had a median survival time of 15.6 months. Among the 346 patients who underwent thoracotomy, 15 patients died postoperatively (4%), and 138 patients (39%) exhibited at least one cardiorespiratory complication postoperatively. We found that patients who had a peak exercise Vo₂ of <65% of predicted (or a peak Vo₂/kg <16 ml/min/kg) were more likely to suffer complications (p = 0.0001) and were also more likely to have a poor outcome (respiratory failure or death) if the peak Vo₂ was <15 ml/min/kg (p = 0.0356). We also found a subset of 58 patients who did not meet FO algorithm criteria for operability, but who still tolerated lung resection with a 2% mortality rate.

Conclusions

Our data provide multicenter validation for the use of exercise Vo₂ for preoperative assessment of lung cancer patients, and we encourage an aggressive approach when evaluating these patients for surgery.