Purpose This study aimed to provide the clinical characteristics, prognostic factors, and 5-year relative survival rates of lung cancer diagnosed in 2015. Materials and MethodsThe demographic risk factors of lung cancer were calculated using the KALC-R (Korean Association of Lung Cancer Registry) cohort in 2015, with survival follow-up until December 31, 2020. The 5-year relative survival rates were estimated using Ederer II methods, and the general population data used the death rate adjusted for sex and age published by the Korea Statistical Information Service from 2015 to 2020. ResultsWe enrolled 2,657 patients with lung cancer who were diagnosed in South Korea in 2015. Of all patients, 2,098 (79.0%) were diagnosed with non-small cell lung cancer (NSCLC) and 345 (13.0%) were diagnosed with small cell lung cancer (SCLC), respectively. Old age, poor performance status, and advanced clinical stage were independent risk factors for both NSCLC and SCLC. In addition, the 5-year relative survival rate declined with advanced stage in both NSCLC (82%, 59%, 16%, 10% as the stage progressed) and SCLC (16%, 4% as the stage progressed). In patients with stage IV adenocarcinoma, the 5-year relative survival rate was higher in the presence of epidermal growth factor receptor (EGFR) mutation (19% vs. 11%) or anaplastic lymphoma kinase (ALK) translocation (38% vs. 11%). ConclusionIn this Korean nationwide survey, the 5-year relative survival rates of NSCLC were 82% at stage I, 59% at stage II, 16% at stage III, and 10% at stage IV, and the 5-year relative survival rates of SCLC were 16% in cases with limited disease, and 4% in cases with extensive disease.

Purpose This study aimed to investigate the differences in characteristics, clinical stages, treatment modalities, and survival outcomes in patients with non‐small‐cell lung cancer (NSCLC) based on sex differences using Korean nationwide registry data. Methods We analyzed the data of 8650 patients diagnosed with NSCLC between 2014 and 2017, obtained from the Korean Association for Lung Cancer Registry (KALC‐R). The Cox proportional hazard model was used to define the differences in survival based on sex. Propensity score matching was used to adjust for differences between men and women. Results Of a total of 10 943 patients, 8650 (79.1%) were diagnosed with NSCLC, of whom 68.7% were men and 31.3% were women. For NSCLC, the median age was higher (69.0 vs. 67.0, p < 0.001) and the proportion of ever‐smokers (84.5% vs. 10.8%, p < 0.001) was higher in men. Adenocarcinoma (55.5% vs. 90.4%, p < 0.001) and stage I NSCLC (26.3% vs. 41.3%, p < 0.001) were more common in women. Survival was significantly lower in men with NSCLC (hazard ratio [HR] 1.493 [95% confidence interval, CI 1.238–1.800], p < 0.001) even after adjusting for meaningful clinical variables, and in the matched cohort (HR 1.339 [1.075–1.667], p = 0.009). Similarly, survival was significantly lower in men with stage IV adenocarcinoma after adjusting for other clinical variables (HR 1.493 [1.238–1.800], p < 0.001) and in the matched cohort (HR 1.339 [1.075–1.667]; p = 0.009). Conclusions Male patients with NSCLC had poorer prognosis, not only after variable adjustments for prognostic factors, but also in the matched cohort.