Predictors of long-term compensatory response of pulmonary function following major lung resection for non-small cell lung cancer

Background and objective: Long-term pulmonary function which might include compensatory response (CR) significantly influences quality of life of long-term survivor after major lung resection. We investigated longterm pulmonary function after major lung resection. Methods: A total of 137 patients who had undergone lobar resection for non-small cell lung cancer (NSCLC) from May 2013 to June 2014 had spirometry at 10-14 months after surgery. Actual post-operative forced expiratory volume in 1 s (FEV1) (FEV1apo)/predicted post-operative FEV1 (FEV1ppo), actual postoperative forced vital capacity (FVC) (FVCapo)/predicted post-operative FVC (FVCppo), its relationship with clinicopathological factors and immunohistochemistry for pro-surfactant protein C (pro-SPC), thyroid transcription factor-1 (TTF-1) and vascular endothelial growth factor receptor 2 (VEGFR2) were investigated. Results: FEV1apo/FEV1ppo showed strong correlation with FVCapo/FVCppo (r = 0.628; P < 0.001). We defined greater CR as both FEV1apo/FEV1ppo and FVCapo/FVCppo were > 120%. Greater CR was significantly associated with decreased smoking index (P < 0.001) and greater resected subsegments (P = 0.037). The never-smoker group revealed significantly greater CR compared with the smoker group in both FEV1apo/FEV1ppo (119.9 +/- 12.5% vs 107.5 +/- 14.2%; P = 0.030) and FVCapo/FVCppo (117.9 +/- 9.98% vs 107.2 +/- 13.1%; P = 0.046) in case-matched comparison. The expression of pro-SPC, TTF-1 and VEGFR2 in the normal lung parenchyma of greater CR group was significantly higher than those of lesser CR group (P < 0.001 for each). In addition, pro-SPC, TTF-1 and VEGFR2 expressions showed a significant correlation to the degree of CR especially in the smoker group (r = 0.631, 0.705 and 0.732, respectively; P < 0.001 for each). Conclusion: Our data suggest that smokers may develop lesser long-term CR after major lung resection. Decreased expression of pro-SPC, TTF-1 and VEGFR2 may indicate decreased capacity of CR,especially in patients who smoke.