Survival and pretreatment prognostic factors for extensive-stage small cell lung cancer: A comprehensive analysis of 358 patients.

Background: Extensive-stage small cell lung cancer (ES-SCLC) is deemed as a fatal malignancy with a poor prognosis. Although immunotherapy has gradually played an important role in the treatment of ES-SCLC since 2018, ES-SCLC treatment data and patient outcome before 2018, when chemotherapy served as a fundamental therapeutic strategy, is still meaningful as a summary of the situation regarding previous medical treatment and is a baseline for comparative data. In addition, the prognostic factors of ES-SCLC have failed to reach a consensus until now. Therefore, this study aimed to evaluate survival and identify the prognostic factors in an ES-SCLC population.

Methods: We retrospectively collected the detailed medical records of 358 patients with ES-SCLC from January 1, 2011 to December 31, 2018 in a Chinese top-level cancer hospital. The prognostic factors were evaluated by Cox univariate and multivariate analysis.

Results: The median overall survival (OS) of ES-SCLC patients (N = 358) was 14.0 months, the one- and two-year OS rates were 56.2% and 21.7%, respectively. Moreover, we identified two demographic characters (age ≥ 70, smoking index ≥ 400), one tumor burden factor (bone multimetastasis), two tumor biomarkers (cyfra211, CA125) and two laboratory indexes (decreased Na, PLR < 76) as independent prognostic factors for OS in this patient population. Progression-free survival (PFS) data of 238 patients was obtained for further analysis, and the median PFS was 6.2 months, and six-month and one-year PFS rates were 51.7% and 14.3%, respectively. Elevated cyfra211, decreased Hb and Na were identified as independent prognostic factors for PFS.

Conclusions: This study provides real-world evidence of the survival and prognosis of ES-SCLC patients which will enable better evaluation and clinical decision-making in the future.