Conference Abstracts - 5th Binaytara Precision Oncology Summit: Redefining Cancer Treatment with Molecular Targeted Strategies
Vol. 5, Issue Supplement 2, 2025 · S1-2
Precision Oncology in Action: A Targeted Approach to Gastroesophageal Junction Adenocarcinoma
Tasnim Rahman, B.S and M.D,Jamie Abad, B.S and M.D,Madison Drallmeier, B.A and D.O,Arhum Mahmood, B.S and M.D
Submission received: 2025-07-15 / Accepted: 2025-08-27 / Published: 2025-12-30
Introduction
Gastroesophageal adenocarcinoma (GEA) remains a major cause of cancer mortality, primarily due to late-stage diagnosis and limited therapeutic options. Recent advances in precision oncology using next-generation sequencing of circulating tumor DNA (ctDNA) are reshaping the management of GEA by enabling personalized, biomarker-driven treatment approaches verses the "one size-fits all" approach. The pathogenesis of GEA is multifactorial, involving genetic mutations, epigenetic modifications, and microbial factors such as Helicobacter Pylori and Epstein-Bar virus (EBV). These insights have been essential for integrating clinical and molecular data in a precision medicine approach. This is a case of GEA in which liquid biopsy played an important role in changing management.
Case Presentation
This is a case of a 40-year-old man who initially presented with persistent and unexplained lymphadenopathy who underwent extensive but inconclusive diagnostic work-up including imaging, multiple biopsies, and laparoscopy. Several months later, he developed dysphagia. EGD revealed a friable mass and biopsy confirmed gastroesophageal junction (GEJ) cancer. Additional imaging revealed widespread hepatic and pulmonary metastasis. Molecular profiling via Gaurdant360 liquid biopsy revealed ERBB2 (HER2) amplification, while PD-L1 immunohistochemistry showed positive score (CPS) of 10. These findings allowed for a change in management from empiric chemotherapy of FOLFIRINOX to a tailored regimen of mFOLFOX combined with Trastuzumab and Pembrolizumab.
Discussion
This case shows how liquid biopsy can inform critical treatment decisions when tissue sampling is delayed or infeasible. While traditional GEA diagnosis relies on invasive procedures and patients are asymptomatic in the early stages, ctDNA-based testing offers a non-invasive alternative that could enhance early detection and early treatment modification. Approximately 7-20% of advanced GEA cases demonstrate HER2 expression, and the integration of HER-2 targeted therapy with the addition of chemotherapy may help overcome some of the diagnostic and therapeutic challenges.
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