CTNI-81. REAL-WORLD TREATMENT RESULTS OF RELAPSED PRIMARY CENTRAL NERVOUS SYSTEM LYMPHOMA TREATED BY MEDICAL THERAPIES

Abstract

Abstract Recurrence of primary central nervous system lymphoma (PCNSL) is a condition which often leads to morbidity and mortality. Consensus regarding the optimal treatment regimen for relapsed PCNSL has not been achieved due to the rarity of the disease. In this study, we conducted a retrospective, single-institution study to investigate real world treatment results of relapsed PCNSL treated by several medical therapeutic regimens. Relapsed PCNSL patients treated at the authors’ institution were identified, and progression-free survival (PFS), overall survival (OS) were analyzed among patients treated by medical therapies. Patients treated by radiotherapy, treated for intraocular or systemic relapses, or best supportive care, were excluded from the survival analysis. 83 patients with first, 44 with second, 25 with third relapse were identified. Upon each relapse, number of patients who received medical therapies for CNS lesions, radiotherapy, treatment for intraocular or systemic relapse, and best supportive care were 48 (57.8%), 5(6%), 4(4.8%), 26(31.3%) (first relapse), 31(70.5%), 3(6.8%), 1(2.3%), 9(20.5%) (second relapse), 13(52.0%), 0, 1(4%), 11(44.0%) (third relapse), respectively. A total of 101 CNS relapses were treated by medical therapies, and PFS (months), OS (months) of the four groups of treatments (rituximab, methotrexate, procarbazine and vincristine [R-MPV], methotrexate [MTX], tirabrutinib, and others) were as follows. PFS: 13.0, 4.5, 2.7, 3.0, and OS: 70.0, 26.4, 51.2, 9.7 (all relapse). PFS: 12.7, 7.0, 3.0, 3.2, and OS: 58.9, 33.1, not reached(n/r), 16.1 (first relapse). PFS: 34.3, 3.9, 25.3, 1.5, and OS: n/r, 28.1, 25.5, 7.5 (second relapse). PFS: 10.1, 3.9, 2.4, 2.9, and OS: 14.9, 22.3, n/r, 8.1 (third relapse). In relapsed PCNSL, favorable PFS was observed in patients treated by R-MPV. Favorable OS was also observed in tirabrutinib, which might suggest that tirabrutinib failure were effectively salvaged by R-MPV. R-MPV might confer better prognosis in relapsed PCNSL.