Feasibility and clinical value of circulating tumor DNA testing in patients with gastric adenocarcinomas

Abstract

Gastric cancer is one of the leading causes of cancer worldwide, and this trend appears to be rising. Most patients are diagnosed at an advanced stage and thus prognosis is poor. Liquid biopsy, or circulating tumor DNA (ctDNA) testing, is emerging as a promising prognostic and/or predictive biomarker for patients with various types of malignancies. Its value and utility for patients with gastrointestinal malignancies, particularly gastric cancer is still being explored. There is ongoing research in other tumor types to suggest that ctDNA testing can be potentially used to identify tumor specific genomic alterations, predict tumor mutation burden, as well as help assess clinical response. We report on the feasibility and clinical value of ctDNA testing in patients with gastric cancers in a real time clinical context by reporting data on cohort of patients with gastric cancers (including those with gastroesophageal junction adenocarcinomas) treated at our institution.

Association of Circulating Tumor DNA With Disease-Free Survival in Breast Cancer

“…Circulating tumor DNA as a predictive biomarker is gaining much appreciation in the field of colorectal cancer, pancreatic cancer, and gastric cancer, among many others. [27][28][29][30] Circulating tumor DNA was first discovered in 1948; however, it has only recently come to prominence because of advances in technologic development and detection methods. 31 Circulating tumor DNA is composed of tiny fragments, accounting for as little as 0.01% of the total circulating DNA (cell-free DNA) with a very short half-life (less than 2 hours).…”

Longitudinal monitoring of circulating tumour DNA improves prognostication and relapse detection in gastroesophageal adenocarcinoma

“…Previous studies have focused on ctDNA analysis in subgroups of GOA such as HER2-positive disease 25 , 44 or advanced/metastatic patients. 18 , 22 , 27 , 45 One previous study 23 used high-sensitivity SNV ddPCR analysis of ctDNA in curative patients as here; however, this did not include longitudinal monitoring. Another study used the commercial guardant360 ctDNA test across a large number of GOA patients with a smaller subset (<30 patients) of neoadjuvant and adjuvant patients where the prognostic significance of ctDNA was outlined.…”

Precision Medicine Tools to Guide Therapy and Monitor Response to Treatment in a HER-2+ Gastric Cancer Patient: Case Report

“…Circulating tumor DNA (ctDNA) is an emerging method to monitor treatment response oftentimes in advance of imaging evidence. The value of ctDNA testing in gastric cancer patients has been studied using targeted panels or specific ddPCR assays to detect somatic mutations and gene amplifications (25–27). In particular, the measurement of HER-2 copy number levels in ctDNA holds great promise for its potential clinical use to identify gastric cancer patients who may benefit from Trastuzumab and to monitor response to treatment and disease progression (27–29).…”