AB079. Whole-brain radiotherapy versus high dose chemotherapy with autologous stem-cell transplantation for consolidation therapy in primary central nervous system lymphoma.

BACKGROUND: Whole brain radiotherapy (WBRT) is commonly used as consolidation therapy in primary central nervous system lymphoma (PCNSL). However, high-dose chemotherapy followed by autologous stem cell transplantation (HD-ASCT) has emerged as an alternative approach for PCNSL. This systematic review aims to assess the efficacy and safety of both treatment modalities. METHODS: The systematic review follows PRISMA guidelines. A comprehensive search strategy identified relevant studies from PubMed, Europe PMC, and Cochrane Library. The following search terms were used: "primary central nervous system lymphoma", "Autologous Stem Cell Transplantation", and "whole-brain radiotherapy". We included randomized controlled trials (RCTs) cohort studies evaluating the use of whole-brain radiotherapy and high-dose chemotherapy followed by autologous stem cell transplantation in the treatment of histologically-confirmed PCNSL. Publications included were limited to English language full texts that were published in the past 10 years. Data extraction & manuscript quality assessment was done by two independent reviewers with a third reviewer to resolve any discrepancy. Primary outcomes include overall survival (OS), progression-free survival (PFS) & treatment related toxicity (TRT). Secondary outcomes were clinical neurological function and performance score assessments. Individual studies were assessed using the Jadad Scale and the Newcastle-Ottawa Scale for observational studies. RESULTS: We identified 5 studies, consisting of 2 RCTs and 3 cohort studies. After all studies considered, analysis revealed that consolidation therapy with HD-ASCT had a better overall PFS and OS compared to whole-brain radiotherapy (P<0.005). Both groups showed similar TRT with mostly haematological toxicity. Holistically clinical cognitive functions are found to be improved in HD-ASCT Patients and poorer results are exhibited by WBRT patients primarily in executive functions. Performance statuses are scored differently across all studies with slightly preferable results shown in patients treated with HDC-ASCT. CONCLUSIONS: Based on the findings of this systematic review, HDC-ASCT might be a preferable choice of consolidative therapy as shown with better OS, PFS with similar TRT. While WBRT are more feasible and cost-efficient, risks of cognitive impairment and reduced performance status after WBRT should be considered for further treatment choices. Further randomized clinical trials with a similar scoring system are needed.