Liquid biopsy at the finish line: End-of-treatment ctDNA predicts relapse and survival in diffuse large B-cell lymphoma.

Abstract

e19116 Background: PET/CT is the primary end-of-treatment (EOT) evaluation for diffuse large B-cell lymphoma (DLBCL); yet, false positives and insufficient prognostic clarity continue to be significant problems. Circulating tumor DNA (ctDNA)-based minimum residual disease (MRD) provides a tumor-informed, noninvasive way to assess recurrence risk. Methods: We used the MEDLINE, Embase, CENTRAL, and Web of Science databases to perform a systematic review and meta-analysis in accordance with PRISMA 2020 guidelines. DLBCL cohorts with end-of-treatment ctDNA-MRD status and survival outcomes were considered eligible research. The key outcome measures were progression-free survival (PFS) and overall survival (OS). Random-effects models calculated hazard ratios (HRs) and measured heterogeneity using I². Results: Eleven trials with 1,247 participants were included. Individuals with ctDNA-MRD had significantly worse progression-free survival (PFS) (pooled HR 5.48, 95% CI 3.96-7.58; I² = 42%) and overall survival (OS) (pooled HR 4.21, 95% CI 2.71-6.54; I² = 36%) compared to those without MRD. In MRD-positive patients, the 24-month recurrence rate was 68% compared to 14% in MRD-negative patients (absolute difference 54%, p < 0.001), with ctDNA indicating return 4.2 months before clinical advancement. In studies reporting combined PET/CT, ctDNA-MRD showed superior predictive performance, with a higher positive predictive value (79% vs 41%) and negative predictive value (92% vs 78%) compared to PET positivity. Conclusions: End-of-treatment ctDNA-MRD is a strong predictor of DLBCL recurrence and survival, outperforming PET/CT for risk classification. Integrating ctDNA-MRD into post-therapy assessments may allow for early intervention and reduce the number of unnecessary biopsies. Clinical Takeaway: ctDNA-MRD at EOT identifies high-risk DLBCL patients missed by imaging and supports precision-guided post-remission management.