This study was a single-centre, retrospective study that retrospectively collected first-line PCNSL patients receiving methotrexate-based chemotherapy ± orelabrutinib at Huashan Hospital of Fudan University. The study was divided into two retrospective cohorts, Cohort A was a cohort of patients receiving methotrexate-based chemotherapy alone, and Cohort B was a cohort of patients receiving methotrexate-based chemotherapy + orelabrutinib.

The study was divided into two retrospective cohorts of approximately 35-40 patients each. Cohort A was the cohort of patients who received methotrexate-based chemotherapy alone, and cohort B was the cohort of patients who received methotrexate-based chemotherapy + orelabrutinib. Statistical analyses such as propensity score analysis (PSM) and inverse probability weighted (IPTW) analysis were performed, focusing on comparing and analysing the short-term efficacy data (ORR, CR) and long-term efficacy data (PFS, OS) of the two cohorts.

Inclusion Criteria:

• Pathologically confirmed primary central nervous system lymphoma
• Methotrexate-based chemotherapy ± orelabrutinib regimen as first-line treatment for patients

Exclusion Criteria:

• Patients receiving ≤2 cycles of treatment without efficacy evaluation
• Those with uncontrolled or significant cardiovascular disease, including: uncontrolled diabetes mellitus, severe cardiac, pulmonary, hepatic, renal insufficiency) and haematological, endocrine system lesions, history of other uncontrollable malignancies

PCNSL is a rare and highly aggressive subtype of primary extranodal non-Hodgkin's lymphoma with a distinctive clinical presentation, and more than 95% of the pathological types are diffuse large B-cell lymphomas.The current National Comprehensive Cancer Network (NCCN) guidelines recommend first-line induction therapy with high-dose methotrexate (HD-MTX) in combination with rituximab, but long-term efficacy is still unsatisfactory, with 50% of patients relapsing at around 2 years