For patients with newly diagnosed or relapsed/metastatic B-cell non-Hodgkin lymphoma following first-line treatment, peripheral blood samples are collected before treatment and at various treatment time points to monitor circulating tumor DNA (ctDNA), aiming to investigate the correlation between dynamic ctDNA changes and patient prognosis.

This study is a prospective, observational, single-center clinical research aimed at exploring the correlation between the dynamic changes of plasma circulating tumor DNA (ctDNA) before and after treatment and the prognosis of patients with B-cell non-Hodgkin's lymphoma (B-NHL). A total of 60 patients who were initially treated with evaluable target lesions and were capable of undergoing molecular pathological testing, either in the initial treatment stage or after relapse/refractory treatment, were planned to be included. All patients will provide peripheral blood samples for ctDNA testing at the pre-treatment stage, during the mid-treatment stage, and after the end of treatment. Simultaneously, standard efficacy assessment PET-CT examinations will be conducted. The primary endpoint of the study is progression-free survival (PFS), while the secondary endpoints include overall response rate (ORR), overall survival (OS), and the consistency analysis between ctDNA clearance rate and PET-CT metabolic complete response (CMR).

Inclusion Criteria:

• Age ≥ 18 years and ≤ 75 years.
• Histopathologically and immunohistochemically confirmed diagnosis of B-cell non-Hodgkin lymphoma (according to the latest WHO classification).
• Presence of at least one evaluable target lesion prior to initial treatment (based on Lugano 2014 criteria).
• Availability of feasible tumor tissue samples or fresh biopsy specimens (from initial diagnosis or relapse biopsy) for establishing a personalized sequencing assay (e.g., identification of patient-specific mutations via tumor tissue DNA sequencing for ctDNA tracking).
• Planned to receive standard regimen therapy (first-line regimen for treatment-naïve patients, second-line regimen for relapsed/refractory patients).
• Eastern Cooperative Oncology Group (ECOG) performance status score of 0-2.
• Voluntary participation in this study with written informed consent provided.

Exclusion Criteria:

• Prior treatment with ≥2 lines of systemic anti-lymphoma therapy.
• Presence of other active malignancies
• History of myocardial infarction within the past 1 year; presence of New York Heart Association (NYHA) class III or IV congestive heart failure, or a history of NYHA class III or IV congestive heart failure, unless left ventricular ejection fraction (LVEF) is ≥50% on echocardiography (ECHO) screening performed within 1 month prior to study entry.
• Hepatic or renal dysfunction: creatinine level ≥176.8 μmol/L (2 mg/dL), transaminase or bilirubin levels >2 × upper limit of normal (ULN).
• Severe hematologic abnormalities: absolute neutrophil count (ANC) <1 × 10⁹/L, platelet count <50 × 10⁹/L.
• Presence of uncontrolled infection.
• Pregnant or breastfeeding women.
• Any other condition that the investigator deems inappropriate for participation in this trial.

patients with newly diagnosed or relapsed/metastatic B-cell non-Hodgkin lymphoma following first-line treatment