PRECISely.

Top Line: Is consolidative whole brain radiation or autologous stem cell transplant superior for patients with primary CNS lymphoma?

The Study: PRECIS was a randomized phase 2 study of patients less than 60 years old with PCNSL. They received induction therapy consisting of 2 cycles of rituximab, methotrexate, BCNU, VP16, and prednisone followed by 2 cycles of rituximab and cytarabine. The overall response rate to induction therapy was 70%. Patients who completed induction therapy were then randomized to receive 40Gy WBRT or ASCT. The original results showed no difference in 2-year overall survival between WBRT and ASCT (75% v 66%), however event free survival was significantly better with ASCT (87% v 69%). So, how do those outcomes compare in long-term follow up? At 8 years, there was still no difference in overall survival between WBRT and ASCT (65% v 69%). However, the rate of relapse was 45% after WBRT compared to just 7% after ASCT, and 8-year EFS was significantly higher with ASCT (67% v 39%). In addition, patients who received WBRT experienced a greater decline in neurocognitive function (69% v 13%). Why the similar OS in short and long-term follow up? In the ASCT arm, the rate of treatment-related death was 11% while a third of relapses after WBRT were successfully salvaged.

TBL: In long-term follow up of the PRECIS trial, ASCT results in less neurocognitive toxicity and a lower risk of relapse with no difference in overall survival. | Houillier, J Clin Oncol 2022