RESUMO
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.
