Abstract 5380: Prognostic utility of minimal residual disease detection using circulating tumor DNA in early-stage breast cancer: A systematic review and meta-analysis.

Abstract Circulating tumor DNA (ctDNA)-based minimal residual disease (MRD) detection is a paradigm shift for risk stratification in early-stage breast cancer (eBC) surveillance. While the prognostic signal is clear, comprehensive synthesis across molecular subtypes remains limited, hindering the translation of prognostic findings into actionable, intervention-guided trials. We conducted a systematic review and meta-analysis following PROSPERO registration (CRD420251122005). Databases including PubMed/MEDLINE, Embase, and Cochrane CENTRAL were searched through September 2025. Studies involving eBC (stage I-III) patients with ctDNA-based MRD detection using validated assays, survival outcomes, and ≥12 months follow-up were included. Random-effects meta-analysis assessed the pooled hazard ratio (HR) for disease recurrence. Subgroup analyses explicitly evaluated molecular subtypes (TNBC, HER2+, HR+/HER2-) based on detection performance and gene mutation profiles. From 1,246 records, 59 studies were included, encompassing 12,847 eBC patients. Meta-analysis demonstrated an extreme prognostic value of disease-free survival from 26 studies with a pooled HR of 9.95 (95% CI: 6.50-15.25, p<0.0001). High heterogeneity was observed (I2=67.2%), largely driven by differences in tumor biology and assay technology. Subtype-specific analysis highlighted distinct shedding rates: TNBC showed the highest baseline detection (80−83.8%) and sensitivity (85−90%). HR+/HER2-showed the lowest baseline detection (14.6−30%). Gene mutation analysis revealed actionability: TP53 predominated in TNBC, while PIK3CA, ESR1, and AKT1 mutations were more frequent in HR+/HER2- disease. Crucially, the time from ctDNA detection to clinical recurrence provided a consistent median lead time of 10.2 months (range 7.5−16months), with cases detected up to 68 months prior. Specificity exceeded 95% across all subtypes. This meta-analysis establishes ctDNA-based MRD detection as a clinically valid biomarker with a nearly 10-fold increased recurrence riskin ctDNA-positive patients. The high heterogeneity underscores the necessity of tailored, subtype-specific surveillance protocols and selection of ultra-sensitive assays. The consistent ∼10-month lead time defines a critical intervention window, providing a clear rationale for ongoing and future randomized clinical trials evaluating ctDNA-guided therapeutic intensification against the distinct molecular profiles observed in each breast cancer subtype. Citation Format: Panuch Eiamprapaporn, Thiti Susiriwatananont, Yaohua Ma, Hataiwan Ratanabunjerdkul, Panchanin Patanayindee, Lucksika Wanichtanom, E. Aubrey Thompson, Saranya Chumsri. Prognostic utility of minimal residual disease detection using circulating tumor DNA in early-stage breast cancer: A systematic review and meta-analysis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl):Abstract nr 5380.