How would you manage a patient with primary CNS lymphoma who is not a candidate for high-dose methotrexate?

This is a relatively rare situation in my experience, but I think WBRT is the second most active agent for PCNSL after high-dose MTX, so if MTX is not possible, I would strongly consider WBRT. Hypothetically, if patient has good PS and you are going for "curative intent", the standard WBRT alone app...