Elimination of Established Risk-Factors in Primary Central Nervous System Lymphoma - Impact of High-Dose Chemotherapy Followed by Autologous Stem-Cell Transplantaion - a Multicenter Retrospective Analysis

High-dose chemotherapy (HDT) and autologous stem-cell transplantation (ASCT) demonstrated high efficacy in the treatment of newly-diagnosed primary CNS lymphoma (PCNSL) in eligible patients (pts). Prognosis of PCNSL is associated with several clinical and histopathological risk factors (RF). Early complete response (CR) during chemotherapy (CHT) was recently reported to be an additional independent prognostic factor in pts undergoing polychemotherapy without HDT+ASCT. In this analysis, we examined the extent to which known RF determined survival in pts who were treated with HDT-ASCT. We additionally investigated the impact of HDT-ASCT specific factors (e.g. conditioning regimen) on survival.

Retrospective multicenter (N=10) analysis of 100 pts with untreated PCNSL who underwent HCT-ASCT with or without whole brain radiotherapy (WBRT). We used univariate and multivariate Cox regression analysis to investigate the prognostic impact of the following factors on overall survival (OS): early CR, age, performance status, involvement of deep brain structures, and LDH serum level and thiotepa dose. Until now data of 82 pts have been analyzed.

Median age at diagnosis was 53 years (range 23–69), the majority was male (67%). After a median follow-up of 58 months median OS was reached after 121 mo (range 3–149 mo). Before HDT+ASCT, 48/82 pts (58%) did not achieve CR (35 PR, 3 SD, 10 PD). After HDT+ASCT, 54/82 pts (66%) were in CR and altogether 39% of the pts were irradiated after HDT+ASCT. Of note, of those pts with PD before HDT+ASCT, 5/10 achieved CR after HDT+ASCT without WBRT. Overall, at the time of last follow-up, 24 pts have died. Of the surviving pts, 50 were in CR (86%), 2 in PR (3%), 2 in SD, and 2 developed progression /relapse. None of the established RF (age, performance status, involvement of deep brain structures, and LDH serum level) significantly distinguished outcome with regard to OS in uni and multivariate analysis. Additionally, neither CR before HDT-ASCT, nor sex nor the dose of thiotepa (10mg versu 20mg/m²) was associated with decreased OS.

We conclude that HCT+ASCT is able to neutralize established RF in PCNSL. HDT+ASCT is a high-efficient treatment option independently of remission rate before entering HDT. New prognostic factors for pts eligible for HCT-ASCT have to be identified to guide therapy and care for PCNSL pts and to define stratification criteria for future trials. Most recent follow up will be presented.

No relevant conflicts of interest to declare.