Abstract
BACKGROUND: Lung cancer is one of the most common malignant tumors worldwide. It is of great significance to conduct in-depth research on early lung cancer with a better prognosis. This study aimed to use the Surveillance, Epidemiology, and End Results (SEER) database to compare the clinicopathological characteristics and survival between early squamous cell carcinoma (SQCC) and adenocarcinoma (AC) under the same treatment model, and develop a nomogram for early lung SQCC. METHODS: This study examined 40,325 cases of stage T1-T2N0M0 lung SQCC and AC from 2004 to 2019. Propensity score matching (PSM) was used to reduce bias. Kaplan-Meier curves and Cox proportional hazards models were used for assessing lung cancer-specific survival (LCSS) and overall survival (OS) under various treatments. A nomogram for early-stage SQCC was constructed and validated using the concordance index (C-index), calibration curves, and decision curve analysis (DCA). RESULTS: In patients with T1-T2N0M0 non-small cell lung cancer (NSCLC), when only radiotherapy was performed, the LCSS of patients in the SQCC group was worse than that of the AC group [hazard ratio (HR) =1.20, 95% confidence interval (CI): 1.079-1.336, P<0.001], and same for 3-year LCSS (55.9% vs. 62.7%) and the 5-year LCSS (43.6% vs. 47.8%). The OS of patients in the SQCC group was worse than the AC group (HR =1.32, 95% CI: 1.215-1.429, P<0.001). When only surgical treatment was performed, no statistically significant difference was found in the LCSS between the two groups (HR =1.03, 95% CI: 0.965-1.092, P=0.41). The OS of patients in the SQCC group was worse than the AC group (HR =1.25, 95% CI: 1.200-1.309, P<0.001). Additionally, a nomogram was created to predict survival rates for early-stage lung SQCC patients. CONCLUSIONS: The prognosis of patients with T1-T2N0M0 lung SQCC is worse than that of AC patients. Individualized treatment is recommended in the early stages.