S5-KL-1 CURRENT TREATMENT FOR DLBCL AND PROPHYLAXIS AND TREATMENT FOR SECONDARY CNS LYMPHOMA

Diffuse large B-cell lymphoma (DLBCL) is the most common subtype of lymphoma, comprising 30% of all lymphoma cases. More than 60% of patients can be cured with current standard treatment, R-CHOP. On the other hand, prognosis of patients with relapsed or refractory DLBCL is disappointing with less than 10% being cured with salvage chemotherapy followed by high-dose chemotherapy with autologous stem cell transplantation. Prognosis of patients with central nervous system (CNS) relapse is especially poor because of a limited treatment option. Thus, evaluating risks of CNS relapse at diagnosis and administering prophylaxis including intrathecal methotrexate (MTX) or systemic high-dose MTX concurrently with R-CHOP or as consolidation therapy in high-risk patients are often-used approach. Clinically, higher risk according to the International Prognostic Index and extranodal involvement in organs such as kidney, adrenal gland, breast, testis, or bone marrow are considered to be high-risk for CNS relapse. Recently, CNS-International Prognostic Index has been proposed to integrate aforementioned risk factors. Moreover, patients with intravascular large B-cell lymphoma, CD5+ DLBCL, double hit lymphoma are reported as high-risk for CNS relapse. Further, the MYD88 L265P mutation, a common mutation in primary CNS DLBCL (PCNSL) is also common in DLBCL of testis or breast, which are the sites associated with CNS relapse. Strategies for CNS prophylaxis have not established yet, and it is still unclear whether intrathecal MTX or high-dose MTX can prevent CNS relapse. Moreover, treatment for secondary CNS relapse have not been established. In particular, for those with both CNS and extra-CNS lesions, effective treatment options are very limited. The role of novel agents such as BTK inhibitors, lenalidomide, and immune check point inhibitors, whose efficacy have been shown for PCNSL, should be investigated further in the management of secondary CNS lymphoma.