Progress in the Treatment and Outcomes for Early-Stage Non-Small Cell Lung Cancer

Purpose: The purpose of this study is to assess temporal trends in population-based treatment and survival rates in patients with early-stage non-small cell lung cancer (NSCLC). Methods: Data were extracted from the Surveillance, Epidemiology, and End Results (SEER) database. Chi-square test, Kaplan-Meier method, and Cox regression models were employed in SPSS 23.0. Results: Fifty-seven thousand and eighty-eight NSCLC patients with early-stage disease from 1988 to 2014 were identified. 6409 (11.2%) were diagnosed in 1988-1994, 5800 (10.2%) 1995-1999, 13,031 (22.8%) 2000-2004, 15,786 (27.7%) 2005-2009, and 16,062 (28.1%) 2010-2014. We observed a significant increase in the proportion of older patients, adenocarcinoma histology, and rate of wedge resection over the study period. The five-year overall survival (OS) for the entire cohort was 63.3%. Those undergoing resection without adjuvant therapy had the highest outcomes. Lobectomy was associated with better outcomes compared to wedge resection or pneumonectomy. A significant difference in five-year OS by year of diagnosis (1988-1994: 58.8% vs. 1995-1999: 60.6% vs. 2000-2004: 63.2% vs. 2005-2009: 66.1%; p < 0.001) was observed. This significant OS difference was also observed regardless of age, surgery type, and T stage, but also only in those with adenocarcinoma. On multivariable analysis, year of diagnosis, age, gender, race, treatment and surgery type, histology, T stage, and tumor grade remained independent prognostic factors for OS. Conclusion: Overall survival for early-stage NSCLC has significantly improved over the recent decades despite an increasing proportion of older patients and those undergoing sublobar resection or SBRT. This finding may be limited to those with adenocarcinoma.