Prognosis Prediction By Two Single Factors Could Predict the Survival of PCNSL Patients Received HD-MTX Therapy without HSCT

Objective：Primary central nervous system lymphoma (PCNSL) is a rare subtype of extra-nodal non-Hodgkin lymphoma and and there is currently no defined standard treatment for newly diagnosed primary central nervous system lymphoma (PCNSL) except for the high-dose methotrexate (HD-MTX). Post-remission consolidation with autologous hematopoietic stem cell transplantation (auto-HSCT) was associated with the best survival outcome. However, not all the patients are available for auto-HSCT and PCNSL displays a wide variability in outcome. This study aimed to identify prognostic factors among individuals with PCNSL undergoing HD-MTX-based regimens without auto-HSCT.

Methods: This retrospective, single-center study included 93 patients diagnosed with PCNSL who underwent HD-MTX-based chemotherapy. Treatment options include: R-MT, R-M, R2-M or RMZ (R rituximab, M methotrexate, T temozolomide, R2 rituximab and lenalidomide, Z zanubrutinib). The dosage of HD-MTX was standardized at 3.5g/m² (adjusted according to the patient's physical condition) and administered every 2-3 weeks per cycle. We collected the patients' clinical characteristics, imaging data, pathology data, treatment plan and follow-up data. Statistical analyses were conducted to identify independent predictors influencing PCNSL prognosis and to establish a prognostic scoring system.

Results: Univariate prognostic analysis of OS showed that male, KPS <70 or ECOG >1, deep brain tissue involvement, GCB phenotype, CD10-positive and Bcl-6-negative were poor prognostic factors for PCNSL. Besides, univariate prognostic analysis of PFS exhibited that males, KPS <70 or ECOG >1 and deep brain tissue involvement have a greater risk of disease progression. Cox multifactorial analysis identified shorter OS in males and Bcl-6-negative cases and shorter PFS in males. Consequently, male gender and Bcl-6 negativity were included in the predictive scoring system, each assigned a value of 1. The median OS was 10 months, 33 months, and not reached (NR) for low-risk, medium-risk and high-risk groups.

Conclusion: Gender disparity was observed in the prognosis of PCNSL patients who received HD-MTX, with males exhibiting worse outcomes in both OS and PFS compared to females. Bcl-6 negativity also correlated with shorter OS. When females with no BCL-6 expression, it generally predicts a worse prognosis.

No relevant conflicts of interest to declare.