Predictive Value of Integrating Circulating Tumor Dna and End-of-treatment Pet/ct for Relapse Prediction in Patients With Diffuse Large B-cell Lymphoma Treated at a Referral Center
Year: 2026
Type: article
Study design: Observational Study
Abstract: Background Diffuse large B-Cell lymphoma (DLBCL) is the most common type of non-Hodgkin’s lymphoma (NHL). End-of-treatment (EOT) FDG-PET/CT is the standard imaging modality for response assessment in diffuse large B-cell lymphoma (DLBCL); however, its ability to accurately identify patients at risk of relapse remains limited. Circulating tumor DNA (ctDNA) has emerged as a promising biomarker for disease burden, treatment response, and detection of molecular residual disease. Aim To evaluate the correlation between ctDNA levels before and at the end of treatment in patients diagnosed with DLBCL, as well as their association with response assessment by PET/CT. Materials and methods Newly diagnosed patients with DLBCL treated at our institution between October 2018 and November 2021 were included. All patients provided written informed consent to participate in the study. Blood samples for plasma ctDNA analysis were collected before treatment (ctDNA1) in dedicated DNA-stabilizing blood collection tubes. Patients underwent chemoimmunotherapy, and eight weeks after treatment completion, a second peripheral blood sample was collected for ctDNA analysis (ctDNA2). Disease staging and treatment response assessment were performed using FDG-PET/CT. At the end of treatment, patients were categorized into four groups: 1) PET/CT-negative / ctDNA2-negative; 2) PET/CT-negative / ctDNA2-positive; 3) PET/CT-positive / ctDNA2-negative; and 4) PET/CT-positive / ctDNA2-positive. Results Eighteen patients were included in the study, with a median age at diagnosis of 59 years and a female predominance (55.6%). Overall, 36.4% had localized disease (stage I/II) and 63.6% had advanced-stage disease (stage IV). Regarding cell of origin, according to the Hans algorithm, 38.9% and 44.4% were classified as germinal center B-cell–like (GCB) and activated B-cell–like (ABC), respectively. Following first-line treatment, 83% of patients achieved a complete response, whereas 11% had primary refractory disease. With a median follow-up of 58 months, one patient experienced relapse after 13 months. At the end of the observation period, seven patients (38%) had died; among them, two had relapsed disease, whereas five were in remission and died from causes unrelated to lymphoma. Among the evaluated groups, a statistically significant difference was observed in both progression-free survival and overall survival curves (p < 0.001), with the best outcomes observed in group 2, followed by group 1, and the worst outcomes in group 4. Conclusion The combined use of PET/CT and ctDNA may represent a useful tool for the assessment of patients with DLBCL. These findings highlight the importance of further studies evaluating longitudinal ctDNA dynamics during follow-up in patients who achieve a complete response, with the aim of better defining its role as a prognostic biomarker.
Language: English
Subfield: Pathology and Forensic Medicine
Field: Medicine
Domain: Health Sciences
Open Access status: diamond
OpenAlex ID: W7223103992