LIBERTY: Liquid Biopsy to Diagnose and Monitor CNS Involvement in High-risk B Cell Non-Hodgkin Lymphoma

Non-Hodgkin B-cell lymphoma (B-NHL) are cancers that arise from a subtype of white blood cells (lymphocyte) and typically involve the lymphatic system; they represent 4% of all cancers \[SEER database, access 2022\]. Despite booming novel antineoplastic agent development, a significant number of aggressive B-NHL patients continue to succumb to their disease, experiencing rapidly progressive disease or early relapse. Central nervous system or CNS (brain, spinal cord and cerebrospinal fluid (CSF)) involvement in aggressive B-NHL is a rare (2-5%) but it is a devastating event, with a life expectancy ranging between 2 and 5 months \[PMID: 30125215\]. Circulating tumor DNA (ctDNA) represents fragmented DNA that originates from tumors cells, carrying specific cancer-associated mutations that can be detected in the blood or other fluids subsumed under "liquid biopsies". The role of ctDNA gained momentum with the advent of high throughput sequencing technologies, becoming increasingly relevant for clinical practice. In lymphoma, detecting and monitoring ctDNA has been shown to be feasible and of high prognostic relevance regarding response and relapse. As such, ctDNA is emerging as a promising biomarker that can provide valuable diagnostic and prognostic information \[PMID: 30125215, PMID: 29449275\]. Identification of patients suffering from aggressive B-NHL at high risk of CNS relapse remains extremely challenging and currently mainly relies on a clinical score (CNS-IPI) \[PMID: 27382100\]. The detection of asymptomatic CNS is limited to conventional techniques and is not standardized \[PMID: 22927246\]. In patients with biopsy-proven CNS lymphoma, ctDNA can be detected in CSF (CSF ctDNA) in approximately 95% of cases. Furthermore, CSF ctDNA is predictive of CNS relapse in a small series of neurologically asymptomatic patients with aggressive B-NHL \[PMID: 36542815, PMID: 32079701, PMID: 34551072\]. Prevention and treatment of CNS involvement remains a great unmet clinical need. The discovery of novel and robust biomarkers is of paramount importance for early detection and risk-adapted therapeutic strategies for CNS involvement. The investigators hypothesize that CSF ctDNA is superior to current standard diagnostic procedures (e.g., flowcytometry or cytology) to detect CNS involvement in high-risk patients. Furthermore, in patients with positive CSF ctDNA, the investigators also postulate that the concept of monitoring minimal residual disease (MRD, small amount of ctDNA that persists in patients that have no signs of active disease on standard imaging techniques) will provide additional information on patient prognosis. This is a multicenter prospective diagnostic study to compare the performance of experimental diagnostic test (ctDNA) versus conventional cytology (CC) and flow cytometry (FC). Each high-risk B-NHL participant will proceed through standard work-up to evaluate potential CNS involvement including a neurological physical examination, a brain MRI and a diagnostic lumbar puncture. Each participant's CSF will be assessed by the two diagnostic tests (CSF ctDNA and conventional test (CC/FC)); the gold standard being proven CNS lymphoma involvement.