Association Of Pik3ca H1047r And Stk11 F354l Mutations With Response To Neoadjuvant Chemoradiotherapy And Survival In Esophageal Cancer.

55Background: Neoadjuvant chemoradiotherapy is the standard treatment for locally advanced esophageal cancer. However, its efficacy is limited in non-responders and there is no reliable clinical parameter in predicting treatment response. We aim to identify chemoradiation-resistant cancers and avoid unnecessary treatments in non-responders with mutation analysis. Methods: Genomic DNA was extracted from diagnostic biopsy specimens of 20 patients (10 with good and 10 with poor response) with esophageal squamous cell carcinoma after neoadjuvant chemoradiotherapy and esophagectomy. Using next-generation sequencing, we screened mutation hotspots in 46 cancer-related genes (Ion AmpliSeq Cancer Panel). Potential predictive genetic variations were validated in another cohort of patients. Chemoradiotherapy response was based on pathological evaluation of surgically resected specimens. The prognostic significance of genetic variations was evaluated with Cox regression survival analysis. Results: In the first cohort...