Plasma cfDNA Testing Guiding the Treatment Decisions of DLBCL

This study is initiated by researchers and is a prospective, single-center, randomized, clinical controlled study. The study subjects are newly diagnosed DLBCL patients with plasma cfDNA positivity (defined as positive for point mutations, CNV, IgH-related fusion, or IG clonal rearrangement). After achieving complete metabolic remission (Lugano response assessment criteria) following 6 cycles of R-CHOP-like chemotherapy, patients undergo plasma cfDNA testing upon enrollment. Plasma cfDNA-negative patients (Group 1) continue to receive monotherapy with rituximab for 2 cycles, while plasma cfDNA-positive patients are randomly assigned to Group 2 and Group 3. Group 2 patients continue monotherapy with rituximab for 2 cycles, and Group 3 patients receive the original regimen for 2 cycles. Plasma cfDNA testing is performed again for all three groups after completion of the entire treatment. Patient progression-free survival (PFS) is observed for 2 years. After treatment completion, follow-up visits are scheduled every 3 months for a total of 24 months.

Research Objective: Evaluate the efficacy and prognosis differences between precision treatment based on plasma cfDNA testing results and the current conventional diagnostic and treatment practices for DLBCL patients.

Expected Results: Determining subsequent treatment based on plasma cfDNA MRD results at the end of DLBCL patient treatment is expected to aid in identifying high-risk patients for early relapse and improving their prognosis.

Inclusion criteria

• Age ≥ 18 years, gender not specified.
• Newly diagnosed patients with diffuse large B-cell lymphoma (DLBCL) confirmed by histopathological examination. Patients should test positive for plasma cfDNA before treatment (defined as positive for point mutations, CNV, IgH-related fusion, or IG clonal rearrangement) and achieve complete metabolic remission after 6 cycles of R-CHOP chemotherapy (evaluated by Lugano response assessment criteria).
• Patients for whom the researcher predicts a life expectancy of >6 months.
• Signed informed consent form.

Exclusion criteria

• Patients who have undergone autologous stem cell transplantation.
• Patients with a history of other malignant tumors, except for basal cell carcinoma of the skin or in situ cervical cancer.
• Patients with uncontrolled cardiovascular diseases, coagulation disorders, connective tissue diseases, severe infectious diseases, and other such conditions;
• Primary central nervous system lymphoma.
• Patients with mental illness or others known or suspected to be unable to fully comply with the study protocol.
• Pregnant or lactating women.
• HbsAg-positive patients who need to undergo HBV-DNA testing and can only be included if they seroconvert. Additionally, if the HbsAg test is negative but the HBcAb test is positive (regardless of HbsAb status), HBV-DNA testing is also required. If the result is positive, inclusion is possible only after seroconversion.
• HIV-infected individuals.
• Other concurrent and uncontrolled diseases that researchers believe may affect the medical condition of patients participating in the study.