I have a 27 year old male who presented to an outside center with some vague symptoms, found to have an high WBC and was diagnosed with CML chronic phase, standard Ph-positive cytogenetics, low Sokal. Started on dasatinib 100mg daily, easily achieved EMR at 3 months and MMR by 6 months. Severe headaches and visual disturbances at the 7 month mark. High CSF WBC on LP with flow confirming lymphoid blast crisis. Repeat bone marrow appeared normal and MMR sustained by pcr on peripheral blood. Cytogenetics now normal. Thus, isolated CNS lymphoid blast crisis of CML, despite excellent response to therapy with the one TKI that can actually penetrate the CSF.
Treated with intrathecal triple therapy - cytarabine, MTX, hydrocortisone - with a good initial response. Continued on dasatinib given the lack of evidence of systemic relapse. After two months, CNS symptoms again appeared and CSF positive with no obvious fixed lesions by MRI. Now treated with craniospinal radiation to full dose. Has an HLA-matched sibling with plans to proceed to stem cell allograft in a couple of weeks.
Questions for discussion are:
1. management of an isolated CNS blast crisis in the face of no obvious systemic recurrence. Would people have changed the dasatinib?
2. post-transplant TKI therapy. I plan to restart dasatinib and give an additional 6 IT treatments starting about 2 months post transplant. Thoughts on this management?