P119. Analysis of circulating tumor DNA to predict risk of recurrence in patients with esophageal and gastric cancers

Saturday, March 7, 2026

9:21 AM - 9:28 AM MST

Location: 101A-C

Co-Author(s)

SS

Samir H. Saeed, B.A.

Student Research Assistant
H. Lee Moffitt Cancer Center and Research Institute
Tampa, Florida, United States
RM

Rutika J. Mehta, M.B., B.S., MD, MPH

Associate Professor in Medicine and Attending Physician
New York-Presbyterian/Weill Cornell Medical Center
New York City, New York, United States
AP

Allan A L Pereira, MD, PhD

Associate Member in the Department of Gastrointestinal Oncology
H. Lee Moffitt Cancer Center and Research Institute
Tampa, Florida, United States
Andrew J. Sinnamon, MD

Surgical Oncologist within the Department of Gastrointestinal Oncology
H. Lee Moffitt Cancer Center and Research Institute
Tampa, Florida, United States
JP

Jose M. Pimiento, MD, FACS (he/him/his)

Surgical Oncologist within the Department of Gastrointestinal Oncology
H. Lee Moffitt Cancer Center and Research Institute
Tampa, Florida, United States

Primary Presenter(s)

Victor P. Gazivoda, MD

CGSO Fellow
H. Lee Moffitt Cancer Center and Research Institute
Tampa, Florida, United States

Slides

Introduction: Presence of circulating tumor DNA (ctDNA) postoperatively is associated with increased risk of recurrence in breast, bladder, lung, and colorectal cancers. Use of ctDNA to identify patients at risk for recurrence in gastroesophageal adenocarcinoma (GEC) has been limited and inconsistent. Our purpose was to assess the utility of ctDNA in detecting recurrence in patients with GEC.

Methods: This is a retrospective institutional study of patients undergoing curative intent resection of GEC with at least one postoperative ctDNA level. ctDNA was evaluated using commercially available personalized, tumor-informed, multiplex-polymerase chain reaction next-generation sequencing assay. Sensitivity and specificity of ctDNA for recurrence detection was assessed. We evaluated recurrence free survival (RFS) by ctDNA positivity. Lead time was calculated from first ctDNA detection to recurrence.

Results: Forty-five patients with curatively resected GEC were included (Gastric: 35, GEJ: 9, Esophageal: 1). Nine of 45 patients had recurrence. Six patients had initially negative postoperative ctDNA and converted to positive before recurrence. With median follow up 604 days (IQR: 361, 891), ctDNA detected recurrence at any point postoperatively with sensitivity of 88.9% and specificity of 86.1%. ctDNA predicted recurrence earlier than radiographic recurrence by a median of 181 days (131, 215). ctDNA detection after 90 days postoperatively was associated with statistically significant poorer RFS [(90 days: median RFS, 186 days vs not reached (NR); HR 5.847 p< 0.05), (6 months: 333 days vs NR; 9.763 p< 0.001), (1 year: 375 days vs NR; 11.454 p< 0.001), (any postoperative: 445 days vs NR; 30.917 p< 0.001)], but not significantly different prior to (60 days: 186 days vs NR; 3.596 p=0.109).

Conclusions: This is one of the largest institutional studies demonstrating postoperative ctDNA detection is a prognostic marker of recurrence in GEC after curative intent surgery. Recurrence may occur despite an initial negative ctDNA. Furthermore, serial monitoring of postoperative ctDNA identifies positive conversion which precedes recurrence by 6 months and provides better prognostic discrimination than single point testing after surgery.

Learning Objectives:

Understand how ctDNA detection is a prognostic marker of recurrence in gastroesophageal adenocarcinoma after curative intent surgery
Understand that serial monitoring of postoperative ctDNA identifies positive conversion and provides better prognostic discrimination than single point testing after surgery
First positive ctDNA precedes imaging recurrence by 6 months