Does CD5 positivity by itself in DLBCL pose a high risk of CNS recurrence and necessitate CNS prophylaxis?   

There are convincing data that de novo CD5+ DLBCL does confer a heightened risk of CNS relapse - in the largest series reported, this risk was 12.7% after treatment with RCHOP chemotherapy, and this despite 15% of patients having received intrathecal methotrexate as prophylaxis [https://doi.org/10.1...