2019 ASCO Annual Meeting!
Session: Gastrointestinal (Noncolorectal) Cancer
Type: Poster Session
Time: Monday June 3, 8:00 AM to 11:00 AM
Location: Hall A
A landscape of circulating tumor DNA in esophageal adenocarcinoma and squamous cell carcinoma.
Esophageal or Gastric Cancer
Gastrointestinal (Noncolorectal) Cancer
2019 ASCO Annual Meeting
Poster Board Number:
Poster Session (Board #175)
J Clin Oncol 37, 2019 (suppl; abstr 4070)
Author(s): Kabir Mody, Rami Manochakian, Daniel H. Ahn, Ali Roberts, Rebecca Nagy, Richard B. Lanman, Pashtoon Murtaza Kasi; Mayo Clinic, Jacksonville, FL; Ohio State University Arthur G. James Cancer Hospital and Richard J. Solove Research Institute, Columbus, OH; Guardant Health, Inc., Redwood City, CA
Background: Esophageal cancer (EC) is a lethal malignancy with limited treatment options. Genomic analyses have led to the elucidation of numerous dysregulated genes in esophageal adenocarcinoma (AC) and squamous cell carcinoma (SCC), and the potential for advancement of targeted therapies in this disease. Data regarding circulating tumor DNA (ctDNA) plasma analysis in EC in real-world clinical practice is limited. Methods: We performed ctDNA next-generation sequencing (NGS) analysis in patients (pts) with EC (January 2015- February 2018). ctDNA analysis was performed using Guardant 360 (Guardant Health, CA) which detects single nucleotide variants and insertion/deletion mutations, and specific amplifications and fusions, in up to 73 different genes. The mutant allele fraction (MAF) for detected alterations was calculated relative to wild type in ctDNA. Therapeutic relevance was defined as alterations within OncoKB levels 1-3B and R1. Results: Among 450 pts, 487 total samples were analyzed (77% AC, 31% SCC). ctDNA NGS revealed at least one genomic alteration (excluding variants of uncertain significance and synonymous mutations) in 81% of pts (90% AC, 88% SCC). Median number of alterations per AC patient was 4 [range, 1-59] and a median MAF of 0.84% (range, 0.02% - 83.7%); SCC was 5 [range, 1-26], with a median MAF of 0.99% (range, 0.01% - 85.2%). The total number of unique alterations was 1,162. The most commonly altered genes in AC: TP53 (70%), KRAS (20%), ERBB2 (18%), EGFR (16%), PIK3CA (16%); in SCC: TP53 (88%), PIK3CA (24%), CCND1 (23%), KRAS (21%), EGFR 15%). Therapeutically relevant alterations will be described. Conclusions: ctDNA plasma profiling of pts with EC is a feasible alternative and non-invasive method to gather comprehensive genomic data. Further large comparison studies to assess landscape of genomic alterations observed through ctDNA versus tissue-based assays, in addition to studies of targeted therapy outcomes based on ctDNA-detected alterations, are needed.