Comparison of Clinical Characteristics and Outcomes in Relapsed Versus De Novo Metastatic Non-Small Cell Lung Cancer.

To compare the clinical characteristics and outcomes between relapsed and de novo metastatic non-small cell lung cancer (NSCLC). We reviewed all NSCLC diagnoses between January 1999 and December 2013 in the institutional Glans-Look Lung Cancer Database, which contains demographic, clinical, pathologic, treatment, and outcome information. Patients with distant metastasis at diagnosis (American Joint Committee on Cancer [AJCC] eighth edition, stage IV), the "de novo" cohort, were compared with the "relapsed" cohort, consisting of patients diagnosed with early stage disease (stage I/II) undergoing curative intent treatment and subsequently experiencing metastatic relapse. Survival analysis, along with univariate and multivariable analysis was performed. A total of 185 relapsed and 3039 de novo patients were identified. Significantly different patterns of smoking history, histology, systemic therapy use, and disease extent were observed between the relapsed and de novo cohorts. Median overall survival from time of metastasis was significantly longer in relapsed than in de novo disease (8.9 vs. 3.7 mo, P<0.001). Relapsed patients demonstrated significant improvements in outcomes over time. In multivariate analysis, de novo metastatic disease continued to bode a worse prognosis (adjusted hazard ratio [HR], 1.4) as did male sex (HR, 1.2), never-smoking history (HR, 1.2), and presence of extrapulmonary metastases (HR, 1.3). Systemic therapy receipt conferred better outcome (HR, 0.4), although the impact of relapsed versus de novo disease on outcomes persisted regardless of systemic therapy receipt. Relapsed and de novo patients represent significantly different subpopulations within metastatic NSCLC with the latter exhibiting poorer survival. This information facilitates discussions about prognosis with patients and supports screening initiatives aimed at reducing de novo disease.