There are several studies comparing the difference between adenocarcinoma (AC) and squamous cell carcinoma (SqCC) of lung cancer. However, seldom studies compare the different overall survival (OS) between AC and SqCC at same clinical or pathological stage. The aim of the study was to investigate the 5-year OS between AC and SqCC groups.

Data were obtained from the Taiwan Society of Cancer Registry. There were 48,296 non-small cell lung cancer (NSCLC) patients analyzed between 2009 and 2014 in this retrospective study. We analyzed both the AC and SqCC groups by age, gender, smoking status, Charlson co-morbidity index (CCI) score, clinical TNM stage, pathological stage, tumor location, histologic grade, pleura invasion, performance status, treatment, stage-specific 5-year OS rate in each clinical stage I–IV and causes of death. We used propensity score matching to reduce the bias.

The AC and SqCC groups are significantly different in age, gender, smoking status, CCI score, clinical TNM stage, pathological stage, tumor location, histologic grade, pleura invasion, performance status, treatment, stage-specific 5-year OS rate in each clinical stage and causes of death (p < 0.0001). The stage-specific 5-year OS rates between AC and SqCC were 79% vs. 47% in stage I; 50% vs. 32% in stage II; 27% vs. 13% in stage III; 6% vs. 2% in stage IV, respectively (all p values < 0.0001).

AC and SqCC have significantly different outcomes in lung cancer. We suggest that these two different cancers should be analyzed separately to provide more precise outcomes in the future.