Autologous Stem-Cell Transplantation for Primary Central Nervous System Lymphoma: Systematic Review and Meta-analysis

While primary central nervous system lymphoma is sensitive to methotrexate chemotherapy, more than half of patients will experience relapse within 5 years. Autologous stem-cell transplantation (ASCT) is increasingly used as consolidative treatment. This systematic review and meta-analysis provides estimates response and survival after ASCT and suggests improved rates compared to the historical data. Background: Primary central nervous system lymphoma (PCNSL) is an aggressive form of non-Hodgkin lymphoma. Methotrexate is first-line chemotherapy. Autologous stem-cell transplantation (ASCT) is increasingly used as an alternative consolidative treatment to whole-brain radiotherapy. Methods: A systematic search of several databases was conducted up through January 10, 2018. Two investigators independently assessed study eligibility and extracted the data. Studies that reported survival outcomes after ASCT were included. Results: We screened 1517 references and included 43 studies. ASCT was used as consolidative treatment or as salvage treatment/at relapse. Thiotepa, busulfan, and cyclophosphamide and carmustine/thiotepa were commonly used conditioning regimens. In the consolidation setting, 94% of patients experienced or maintained complete or partial response after ASCT. The rates of overall survival (OS) and progression-free survival (PFS) were 94%, 86%, 82%, and 70% and 79%, 70%, 64%, and 54% after 1, 2, 3, and 5 years, respectively. The overall risk of relapse at 5 years was 24%. In the salvage/relapse settings, 85% of patients experienced or maintained complete response or partial response after ASCT. The rates of OS and PFS were 75%, 63%, 56%, and 54% and 85%, 62%, 59%, and 54% after 1, 2, 3, and 5 years, respectively. The risk of relapse at 5 years was 29%. Subgroup analysis showed that the use of carmustine and thiotepa as a conditioning regimen carried the lowest risk of transplant-related mortality. The thiotepa, busulfan, and cyclophosphamide regimen, on the other hand, showed numerically superior OS and PFS rates. Conclusion: This review provides estimates for response and survival to aid in decision making when considering ASCT for patients with PCNSL.