Impact of Sublobar Resection on Pulmonary Function: Long-Term Results from American College of Surgeons Oncology Group Z4032 (Alliance)

Abstract

Sublobar resection (SR) in high-risk operable patients may result in a long-term decrease in pulmonary function. We previously reported 3-month pulmonary function outcomes from a randomized phase III study of SR alone compared with SR with brachytherapy in patients with non-small cell lung cancer. We now report long-term pulmonary function after SR. Pulmonary function was measured at baseline and at 3, 12, and 24 months. A decline of 10% or more from baseline in the percentage predicted forced expiratory volume of 1 percentage or in the diffusion capacity of the lung for carbon monoxide was considered clinically meaningful. The effect of study arm, tumor location, size, approach (video-assisted thoracoscopic surgery vs thoracotomy), and SR type (wedge vs segmentectomy) on pulmonary function was assessed using a Wilcoxon rank sum test. A generalized estimating equation model was used to assess the effect of each factor on longitudinal data, including all four time points. Complete pulmonary function data at all time points was available in 69 patients. No significant differences were observed in pulmonary function between SR and SR with brachytherapy, thus the study arms were combined for all analyses. A decline of 10% or more (p=0.02) in the percentage predicted forced expiratory volume in 1 second was demonstrated for lower-lobe resections at 3 months but was not at 12 or 24 months. A decline of 10% or more (p= 0.05) in the percentage predicted diffusion capacity of the lung for carbon monoxide was seen for thoracotomy at 3 months but was not at 12 or 24 months. Clinically meaningful declines in pulmonary function occurred after lower lobe resection and after thoracotomy at 3 months but subsequently recovered. This study suggests that SR does not result in sustained decreased pulmonary function in high-risk operable patients.