Recent advances and challenges in primary central nervous system lymphoma: a narrative review

Primary central nervous system lymphoma (PCNSL) is a rare and highly invasive non-Hodgkin lymphoma that is challenging to diagnose and treat. It is typically confined to the brain, spinal cord, and eyes. The diagnosis of PCNSL lacks specificity, and the misdiagnosis and missed diagnosis rates of PCNSL are high. Traditional treatments for PCNSL, such as surgery, whole-brain radiation therapy, high-dose methotrexate-based chemotherapy, and rituximab (RTX), have been associated with higher initial remission rates. However, the duration of any remission is short, the recurrence rate is high, and treatment-related neurotoxicity is strong, which are challenges for medical researchers. This review provides an overview of and perspectives on the diagnosis, treatment, and evaluation of patients with PCNSL.

The PubMed database was searched to retrieve articles published from January 1, 1991, to June 2, 2022 using the following Medical Subject Headings (MeSH) terms: "Primary central nervous system lymphoma" and "clinical trial". The American Society of Clinical Oncology and the National Comprehensive Cancer Network guidelines were also reviewed to obtain additional information. The search was limited to articles published in English, German, and French. In total, 126 articles were deemed eligible for inclusion in this study.

In terms of the diagnosis of PCNSL, a combination of flow cytometry and cytology has been shown to improve the diagnostic accuracy of PCNSL. Additionally, interleukin 10 and chemokine C-X-C motif ligand 13 are promising biomarkers. In terms of the treatment of PCNSL, programmed death-1 (PD-1) blockage and chimeric antigen receptor T cell (CAR-T) therapy treatments have shown prospective efficacy, but more clinical trials need to be conducted to gather further evidence. We also reviewed and summarized prospective clinical trials on PCNSL.

PCNSL is a rare and highly aggressive lymphoma. The treatment of PCNSL has progressed significantly, and while the survival of patients has improved, relapse and low long-term survival remain huge challenges. Continuous in-depth research is being conducted on new drug therapies and combination therapies for PCNSL. A combination of targeted drugs (e.g., ibrutinib, lenalidomide, and PD-1 monoclonal antibody) and traditional therapy represents the main research direction for future PCNSL treatments. CAR-T has also shown great potential in the treatment of PCNSL. With the development of these new diagnostic and therapeutic methods and further research into the molecular biology of PCNSL, patients with PCNSL should achieve a better prognosis.