Fall in diffusing capacity associated with induction therapy for lung cancer: A predictor of postoperative complication?

Background. Pulmonary resection after induction therapy is associated with high rates of pulmonary morbidity and mortality. However, the impact of induction therapy on the pulmonary toxicity and associated pulmonary complications has not been fully investigated in the setting of lung cancer surgery. Methods. We assessed the 66 consecutive patients who underwent a pulmonary resection after induction therapy, 48 of whom received chemoradiotherapy and 18, chemotherapy alone. Results of pulmonary function before and after induction therapy were compared, and logistic regression analyses utilized to explore the risk factors of pulmonary morbidity. Results. After induction therapy, forced expiratory volume in 1 second (FEV1) was increased significantly (from 2.28 +/- 0.61 L to 2.40 +/- 0.62 L; p < 0.05); however, percent vital capacity (%VC) and FEV1/FVC did not change significantly. The diffusing capacity of lung for carbon monoxide (D-LCO) was decreased significantly by 21% (from 90.3% +/- 18.3% to 71.1% +/- 12.5%; p < 0.0005). Patients with respiratory complication showed lower predicted postoperative %FEV1 (49.5% +/- 11.1% versus 57.2% +/- 14.2%; p = 0.031) and predicted postoperative %D-LCO (41.9% +/- 8.0% versus 55.4% +/- 10.1%; p < 0.0001) results than those without complications. Univariate and multivariate analyses revealed that predicted postoperative %D-LCO alone was an independent factor to predict postoperative pulmonary morbidity. Conclusions. For patients who undergo a pulmonary resection after induction therapy, predicted postoperative % D-LCO is more important to predict pulmonary morbidity rather than static pulmonary function (predicted postoperative % VC or % FEV1). The decrease in D-LCO is thought to reflect a limited gas exchange reserve, caused by the potential toxicity of chemotherapy or chemoradiotherapy. We believe that the impact of diffusion limitation after induction therapy should to be emphasized to decrease the pulmonary morbidity.