Abstract 4556: Postoperative minimal residual disease detection using tumor-informed circulating tumor DNA analysis in stage II-III gastric cancer

作者：Bom Han, Hayoon Lee, Minkyu Jung, Bum Jun Kim, Yongjun Cha, Sunghoon Heo, Sun Young Rha, Hyung-Don Kim, Min‐Hee Ryu, Dong‐Hoe Koo, Jong Gwang Kim, Hye Sook Han, Sun Jin Sym, Jae-Joon Kim, Do-Youn Oh, Keun Wook Lee, Hwang‐Phill Kim, Duhee Bang, Sang‐Hyun Song, Tae‐You Kim, Dae Young Zang · 发表于：Cancer Research · 年份：2025 · DOI：10.1158/1538-7445.am2025-4556 · 被引用次数：2 · 研究领域：Cancer Genomics and Diagnostics、Gastric Cancer Management and Outcomes、Cholangiocarcinoma and Gallbladder Cancer Studies

Abstract Background: Circulating tumor DNA (ctDNA) analysis enables the detection of minimal residual disease (MRD), offering potential for improved risk stratification and guidance on decisions regarding adjuvant chemotherapy (ACT). We investigated the clinical utility of tumor-informed ctDNA analysis for postoperative MRD assessment in stage II-III gastric cancer (GC). Methods: We plan to enroll 100 patients from the 976 expected in the ongoing EXODOX study (NCT04787354), a phase III randomized trial comparing reduced-duration XELOX with the standard 6-month regimen as ACT in patients with pathologic stage II-III GC after curative resection. In this sub-study, ctDNA MRD was assessed using the CancerDetectTM assay (IMBdx, Inc.), a targeted sequencing method with a tumor-informed bespoke panel (BSP). To create the BSP, whole exome sequencing of tumor tissue and paired white blood cells identified up to 100 patient-specific variants. Whole blood (20 mL) was collected at five postoperative time points: 3-10 weeks (P0), 6 months (P1), 12 months (P2), 18 months (P3), and 24 months (P4). CtDNA MRD positivity was defined as the detection of two or more BSP variants in plasma. Results: This analysis includes 42 patients enrolled from May 2022 to August 2024, with ctDNA MRD assessed at three time points: P0 (n = 42), P1 (n = 27), and P2 (n = 17). The median age was 66 years (range, 39-96); 27 patients (64.3%) were male, all had adenocarcinoma, and 30 patients (71.4%) had stage III di...