Consolidative Autologous Stem Cell Transplantation Versus Whole Brain Radiation in PCNSL; a Nationwide Analysis

The best consolidation strategy after induction chemotherapy in Primary CNS Lymphoma (PCNSL) remains controversial. Our objective is to estimate the overall survival (OS) for autologous stem cell transplantation (ASCT) versus whole brain radiation (WBRT) in the consolidation setting. We also sought to evaluate the factors affecting treatment selection METHODS: We identified 1620 patients with PCNSL who received chemotherapy followed by either ASCT or WBRT between 2004 and 2015 from the National Cancer Database. A propensity score weighting methodology was used to compare survival outcomes. Factors affecting treatment selection were investigated using a logistic regression model. Annual percentage change (APC) was calculated to assess the trend of ASCT use.

Only 12.2% of patients received ASCT, and this proportion rose steadily between 2004 and 2015, with APC of +23%. Treatment selection was affected by age, type of area, distance from the treating facility, and level of education. With a median follow-up of 68.4 months, adjusted-median OS was 91.4 months and not reached for WBRT and ASCT groups, respectively (P < .001). 5-year OS was 74.4% in the ASCT group versus 58.7% in the WBRT group (HR 0.40, 95% CI 0.27-0.60, P -value < .01).

Socioeconomic factors affect the selection of consolidative treatment in patients with PCNSL which can alter outcomes. Frequency of consolidative ASCT is increasing for patients with PCNSL. This is the first and largest cohort study, to our knowledge, to show an OS advantage in favor of ASCT. This OS benefit needs to be confirmed in a randomized controlled fashion.