A comparison of the functional parameters of operability in patients with post-inflammatory lung disease and those with lung cancer requiring lung resection.

Abstract

Background It is a common, yet unproven, belief that patients with post-inflammatory lung disease have a better functional reserve than patients with lung cancer when compared with their respective functional parameters of operability – forced expiratory volume in one second (FEV1), maximum oxygen uptake in litres per minute (VO2 max) and the diffusion capacity for carbon monoxide (DLCO). Objectives The aim of this study was to compare a group of patients with lung cancer with a group with post-inflammatory lung disease according to their respective functional parameters of operability. We also aimed to investigate any associations of FEV1 and/or DLCO with VO2 max within the two groups. Methods We retrospectively included 100 adult patients considered for lung resection. All patients were worked up using a validated algorithm and were then sub-analysed according to their parameters of functional operability. Results Two-thirds of patients had post-inflammatory lung diseases whilst the rest had lung cancer. The majority of the patients in the lung cancer group had coexistent chronic obstructive pulmonary disease (COPD) (n=18). Most (n=47) of the patients in the post-inflammatory group were diagnosed with a form of pulmonary TB (active or previous). Among the two groups, the lung cancer group had a higher median %FEV1 value (62.0%; interquartile range (IQR) 51.0 - 76.0) compared with the post-inflammatory group (52%; IQR 42.0 - 63.0; p=0.01). There was no difference for the %DLCO and %VO2 max values. The lung cancer group also had higher predicted postoperative (ppo) values for %FEV1 (41.0%; IQR 31.0 - 58.0 v. 34.0%; IQR 23.0 - 46.0; p=0.03, respectively) and %VO2 max (58.0%; IQR 44.0 - 68.0 v. 46.0%; IQR 35.0 - 60.0; p=0.02). There was no difference in the %DLCO ppo values between the groups. Conclusion Patients with lung cancer had higher percentage values for FEV1 and ppo parameters for %FEV1 and %VO2 max compared with those who had post-inflammatory lung disease. Our findings suggest that lung cancer patients have a better functional reserve.