Prognostic Factors Differ by Tumor Stage for Small Cell Lung Cancer: A Pooled Analysis of North Central Cancer Treatment Group Trials

An analysis of 14 small cell lung cancer (SCLC) trials was performed to improve the current understanding of potential prognostic factors for overall survival (OS) and progression-free survival (PFS) in groups of patients with limited-stage disease SCLC (LD-SCLC) and extensive-stage disease SCLC (ED-SCLC) separately. Data on 688 patients with LD-SCLC and 910 patients with ED-SCLC were included. Clinical and laboratory factors were tested for their prognostic significance using Cox regression models that were stratified by protocol. Recursive partitioning and amalgamation (RPA) analyses were used to identify prognostic subgroups. Poorer performance status (PS) led to worse OS and PFS in the ED-SCLC group but not in the LD-SCLC group. The prognostic impact of PS was strong for men but weak for women in the ED-SCLC group (interaction P value