A 14-gene expression assay that uses quantitative PCR, runs on formalin-fixed paraffin-embedded tissue samples, and differentiates patients with heterogeneous statistical prognoses was developed in a cohort of 361 patients with non-squamous NSCLC resected at the University of California, San Francisco. The assay was then independently validated by the Kaiser Permanente Division of Research in a masked cohort of 433 patients with stage I non-squamous NSCLC resected at Kaiser Permanente Northern California hospitals, and on a cohort of 1006 patients with stage I-III non-squamous NSCLC resected in several leading Chinese cancer centres that are part of the China Clinical Trials Consortium (CCTC).
Kaplan-Meier analysis of the Kaiser validation cohort showed 5 year overall survival of 71路4%(95%CI 60路5-80路0) in low-risk, 58路3%(48路9-66路6) in intermediate-risk, and 49路2%(42路2-55路8) in high-risk patients (ptrend=0路0003). Similar analysis of the CCTC cohort indicated 5 year overall survivals of 74路1%(66路0-80路6) in low-risk, 57路4%(48路3-65路5) in intermediate-risk, and 44路6%(40路2-48路9) in high-risk patients (ptrend<0路0001). Multivariate analysis in both cohorts indicated that no standard clinical risk factors could account for, or provide, the prognostic information derived from tumour gene expression. The assay improved prognostic accuracy beyond National Comprehensive Cancer Network criteria for stage I high-risk tumours (p<0路0001), and differentiated low-risk, intermediate-risk, and high-risk patients within all disease stages.
Our practical, quantitative-PCR-based assay reliably identified patients with early-stage non-squamous NSCLC at high risk for mortality after surgical resection.
UCSF Thoracic Oncology Laboratory and Pinpoint Genomics.