Primary nervous system lymphomas (PCNSL) are aggressive malignancies, exhibiting one of the worst prognoses among lymphomas. The best treatment modality for PCNSL has not yet been identified. A recent consensus reached an agreement that intrathecal chemotherapy can be left out if a sufficiently high dose of MTX is given intravenously. Moreover, many investigators are joining forces to optimize the collection of patient information and the performance of clinical trials. This will ensure a more rapid accrual in this rare disease and the conduct of several concomitant trials for different patient subgroups based on age and other prognostic factors. Strictly speaking a high dose methotrexate regimen, is recommended by NCCN or the Consensus Meeting (Summary, stated below). While all experts agree that ideally more trials are needed, the consensus meeting was held precisely because they are not expected to be performed due to rarity of this disease. Treatments that comply with the NCCN and Consensus guidelines should be considered favorably. Long term results of sequential high-dose MTX containing chemotherapy followed by high-dose carmustine/thiotepa plus ASCT (±whole brain irradiation) is safe and leads to high survival rates after first line in eligible patients with newly diagnosed PCNSL(Kasenda et al). However, NCCN(2011, PCNS-3) recommends it only for relapsing disease: “Consider high-dose chemotherapy with stem cell rescue(level 2B recommendation). In addition to the high dose therapy with stem cell rescue, NCCN lists retreatment with high dose methotrexate, systemic chemotherapy and re-irradiation, as well as supportive care.
Gauthier J et al, Allogeneic hematopoietic cell transplantation for diffuse large B cell lymphoma: Guidelines from the Francophone Society of Bone Marrow Transplantation and Cellular Therapy (SFGM-TC). Bull Cancer. 2017 Dec;104(12S):S131-S135.
B. Kasenda et al, Prognosis after high-dose chemotherapy followed by autologous stem-cell transplantation as first-line treatment in primary CNS lymphoma—a long-term follow-up study Ann Oncol (2012)
NNC, PCSN Lymphoma 2019