Outcomes of Consecutively Diagnosed Primary Central Nervous System Lymphoma Patients Using the Alberta Lymphoma Clinical Practice Guideline Incorporating Thiotepa-Busulfan Conditioning for Transplantation-Eligible Patients.

While no widely accepted standard treatment regimen exists for primary central nervous system lymphoma (PCNSL), growing evidence supports an approach that incorporates autologous stem cell transplantation (ASCT) as consolidative therapy when feasible. In November 2011, the Alberta Hematology Tumor Team established a new clinical practice guideline (CPG) for PCNSL involving high-dose methotrexate (HDMTX)/cytarabine-based induction followed by ASCT for eligible patients using a thiotepa and busulfan (TBu) conditioning regimen that omitted cyclophosphamide from the regimen that was used before 2011. This retrospective study analyzed all 64 patients with PCNSL diagnosed consecutively in 3 Canadian centers between November 2011 and December 2017 to evaluate adherence to the 2011 CPG and associated outcomes. Of the 64 patients with PCNSL, 38 were initiated on the transplantation-eligible protocol, of whom 30 underwent successful ASCT, and 26 were deemed transplantation-ineligible, of whom only 7 completed the transplantation-ineligible HDMTX-based protocol. For the transplantation-eligible and -ineligible cohorts, the projected 3-year overall survival (OS) rates were 83.8% and 14.3% and progression-free survival (PFS) rates were 78.1% and 0%, respectively. For the 30 patients who underwent TBu/ASCT, the 3-year OS and PFS rates were 92.7% and 88.9%, respectively, with no treatment-related mortality or significant neurotoxicity. These real-world results highlight the efficacy and tolerability of TBu/ASCT consolidation for PCNSL in patients young and fit enough for an intensive treatment program, along with the significant need for improved therapies for older or less fit patients with PCNSL.