ctDNA-guided Therapy Optimization in Newly Diagnosed DLBCL

This study is using circulating tumor DNA (ctDNA) — tiny fragments of cancer DNA found in the blood — to guide treatment decisions in patients newly diagnosed with diffuse large B-cell lymphoma (DLBCL), the most common type of aggressive blood cancer. The goal is to optimize therapy based on how a patient's cancer is responding in real time. **You may be eligible if...** - You are 18 or older and have been newly diagnosed with DLBCL (a type of non-Hodgkin lymphoma) confirmed by biopsy - Your cancer is stage II, III, or IV - You are planned to receive standard immunochemotherapy (R-CHOP or a similar regimen) - You have at least one measurable tumor on imaging - Your heart and organ function is adequate to receive standard treatment **You may NOT be eligible if...** - You have been previously treated for DLBCL (with limited exceptions such as a short course of steroids or one cycle of chemotherapy) - You have transformed lymphoma (another lymphoma type that changed into DLBCL) - You have active central nervous system lymphoma - You have a serious coexisting illness that would interfere with treatment Talk to your doctor to see if this trial is right for you.