The objective of the observation is to collect and document data on treatment strategies for secondary central nervous system lymphoma (SCNSL) in routine clinical practice, whether obtained in the context of clinical trials or outside of trials. In particular, the following questions will be specified:

• What therapeutic approaches are being pursued?
• What is the clinical outcome of the various treatment options?
• What is the frequency of serious adverse events with each therapeutic approach?

The observational study is to be conducted in inpatient clinics, outpatient clinics and by oncology physicians in private practice. The investigators will be invited to participate by the Charité - CNS Lymphoma Working Group (Charité AG ZNSL) or the Competence Network Malignant Lymphomas (KML). When a patient is reported, the personal data of the physician including the patient will be recorded and compiled in the form of a list documentation.

All patients with SCNSL can and should be included in the study regardless of which therapy options are used and regardless of whether it is a first-line treatment, the treatment of a recurrence or a maintenance therapy for SCNSL. No intervention is associated with the conduct of the observational study with regard to the selection and implementation of the specific therapeutic regimen, diagnostics, and examination frequency during and after treatment.

The following information should be documented:

• Patient demographics and medical history
• Tumor extent at the time of initial diagnosis and CNS involvement
• Prior therapy
• General condition
• Therapy regimen for the CNS involvement
• Response
• Adverse drug reactions
• Tolerability of therapy: acute toxicity
• Chronic therapy toxicity, especially late neurotoxicity
• Time to treatment failure (relapse or progression)
• Death from any cause

Inclusion Criteria:

• All patients with SCNSL can and should be included in the registry regardless of which treatment options are used and whether the treatment being given is first-line, recurrence, or maintenance therapy for SCNSL.

Exclusion Criteria:

• None

All patients with SCNSL