Improved long-term survival following pulmonary resections for non-small cell lung cancer: results of a nationwide study from Iceland.

Background: We studied the outcome of pulmonary resection with curative intent for non-small cell lung cancer (NSCLC) in a nationwide study covering a 24-year period, focusing on survival. Methods: All patients who underwent pulmonary resection for NSCLC in Iceland in the period 1991-2014 were reviewed for demographics, TNM stage and survival. Median length of follow-up was 45 months. Three 8-year periods were compared, overall survival was estimated, and prognostic factors for survival were identified. Results: Altogether, 652 surgical resections were performed on 644 individuals (52% females): 492 lobectomies (75%), 77 pneumonectomies (12%), and 83 sublobar resections (13%). Mean age increased from 65 to 68 yrs during the study period (P=0.002). The number of cases operated at stage IA increased substantially between the first and last periods (29% vs. 37%; P<0.001). Survival improved from 75% to 88% at 1 year and from 38% to 53% at 5 years (P<0.001). Independent prognostic factors for mortality were advanced TNM stage (HR = 2.68 for stage IIIA vs. I), age (HR = 1.04), ischaemic heart disease (HR = 1.26), any minor complication (HR = 1.26), and sublobar resection (HR = 1.33), but surgical margins free from tumour growth (HR = 0.59) and treatment during the latter two eight-year periods were predictors of lower mortality. The best survival was seen between 2007 and 2014 (HR = 0.61, 95% CI: 0.48-0.78; P<0.001). Conclusions: Survival of patients who have undergone pulmonary resection for NSCLC has improved significantly in Iceland. This may be explained by the increased number of patients diagnosed at lower stages and improved preoperative staging, with fewer understaged patients.