ctDNA and Metabolites in CSF as Early Biomarkers of Secondary CNS Involvement in Diffuse Large B-cell Lymphoma

Diffuse Large B-cell Lymphoma is a malignant, aggressive cancer representing 40% of Non-Hodgkin Lymphomas globally. The risk of relapse after primary treatment is approximately 30% of which up to 10 % occurs in the central nervous system (CNS). The prognosis after CNS relapse is severely discouraging with an overall survival of 3-6 months. Currently CNS relapse is diagnosed by either flow cytometry performed on cerebrospinal fluid or a stereotactic biopsy based on tumor localization by an MRI scan. Both diagnostic methods however require a certain tumor mass in order avoid false negative test results. The purpose of this study is to learn whether tumor-derived cell-free circulating DNA (cfDNA) and/or metabolite profiles from diffuse large B-cell lymphoma (DLBCL) cells can be identified in the cerebrospinal fluid (CSF), before the malignant cells themselves are detectable in CSF. Thus the investigators aim to investigate the diagnostic potential of cfDNA and/or metabolites measured in blood and cerebrospinal fluid. The study is based on the following four hypotheses: Hypothesis 1: Measurement of cfDNA and/or metabolites in CSF are more sensitive methods of detecting DLBCL involvement in CNS compared to conventional diagnostics. Hypothesis 2: Quantitative cfDNA/metabolomics in CSF has independent prognostic value in DLBCL. Hypothesis 3: cfDNA and/or metabolite profile in CSF detected at primary diagnosis predicts relapse of DLBCL in the CNS also when CNS-IPI is taken into account. Hypothesis 4: Particular aberrations of cfDNA and/or metabolite profiles detected in blood (plasma) may, in some cases, be associated with CNS involvement in DLBCL patients and/or predict CNS relapse. The study is composed of a pilot study including 5 patients with verified either primary or secondary CNS lymphoma followed by two studies: One including 40 patients with de novo DLBCL and one including 30 patients in a relapse setting. The patients will have to consent to having a lumbar puncture performed and blood samples taken before treatment initiation. After treatment a second set of lumbar puncture and blood samples will be requested.