Novel Genomic Prognostic Factors For Nonsurgical Esophageal Squamous Cell Carcinoma Treated With Concurrent Chemoradiotherapy.

e15589 Background: Definitive concurrent chemoradiation therapy (dCRT) is the standard treatment for patients with nonsurgical esophageal squamous cell carcinoma (ESCC), yet patients demonstrated great variations in responses and post-treatment progression inevitably. Methods: To identify prognostic factors that could assist in clinical judgment and make predictions ahead of disease relapse, we performed a targeted next generation sequencing of 416 cancer-related genes on primary tumor biopsies from 47 ESCC patients with locally advanced or metastatic nonsurgical diseases. Patients were subjected to dCRT treatment and local recurrence free survival (LRFS), progression free survival (PFS) and overall survival (OS) times were analyzed. Results: TP53 (78%), NOTCH1 (32%), ARID1A (13%), FAT1 (13%) and CDKN2A (13%) are the most commonly mutated genes in ESCC, while copy number gains are frequently occurred in MCL1 (36%), FGF19 (34%), MYC (32%), CCND1 (27%), ZNF217 (15%), CDKN2A (13%) and YAP1 (11%). Multivariate analysis including clinical variables (age, gender and disease stage) and individual genetic alterations suggested that gender is an independent prognostic factor and male tend to have longer LRFS, PFS and OS after dCRT treatment. In addition, YAP1 amplification likely increased the risk of disease progression and death. To remove the impact of gender on prognosis, gender stratified survival analysis was performed and found that male patients with YAP1 amplification had significantly shorter LRFS (p = 0.002) and OS (p = 0.03), and also demonstrated a certain trend toward a shorter PFS (p = 0.06) than male patients without YAP1 amplification. Conclusions: YAP1 amplification might be a potentially useful biomarker in predicting treatment outcomes and selecting patients with high relapse risk for closely monitoring.