Fotemustine-Containing Regimens Versus Regimens Based on High-Dose Methotrexate in Newly Diagnosed PCNSL

Objective: This study was conducted to compare the effectiveness and safety of fotemustine-containing regimens and high-dose methotrexate-based regimens in newly diagnosed primary central nervous system lymphoma(PCNSL). Methods: From April 2012 to April 2020, 88 patients with PCNSL who received fotemustine-containing regimens and regimens based on high-dose methotrexate were retrospectively assessed in this study.47 patients were treated with fotemustine-containing regimens, of which 25 patients were treated with R-FPD (Rituximab , formustine, pemetrexed, dexamethasone) regimen, and the other 22 patients were treated with FVD (formustine, vincristine,dexamethasone) regimen. 41 patients were treated with high-dose methotrexate-based regimens, of which 26 patients were treated with MA(Methotrexate ,Cytarabine ) regimen, of which 8 patients were treated with R-MT(Rituximab ,methotrexate ,temozolomide)regimen,of which 5 patients were treated with R-MA(Rituximab ,methotrexate ,Cytarabine) regimen, and the other 2 patients were treated with RM(Rituximab ,methotrexate) combined Zebutinib regimen. Results: In the fotemustine-containing regimen groups (n=47), 18 cases were complete response(CR), 19 cases were partial response(PR), 6 cases were

stable disease (SD), 4 cases were disease progression (PD), objective response rate(ORR )was 79%, and diease contral rate(DCR) was 91%.10 cases were CR in the high-dose methotrexate groups (n=41) , 17 cases of PR, 7 cases of SD, 7 cases of PD, ORR was 66%, DCR was 83%.there was no significant difference in ORR (79%vs66%, P=0.176)and DCR(91%vs83% , P=0.226) between the two groups.No significant difference was observed in the 2-year PFS rate (19.4%vs10%, P=0.149) and 3-year OS rate (24%vs15%, P=0.200) between the two groups. The main adverse reactions in the high-dose methotrexate groups were myelosuppression and mucositis. In the fotemustine-containing regimen groups, myelosuppression was the main adverse reaction. The incidence of leukopenia of grade 3 and above in the high-dose methotrexate groups and fotemustine groups was 54% and 23%, respectively. The high-dose methotrexate groups had more severe leukopenia (P= 0.001). The incidence of mucositis in the high-dose methotrexate groups (68%) was significantly higher than that in the fotemustine group (26%). Conclusion: The fotemustine-containing regimens for the treatment of newly diagnosed PCNSL has the similar efficacy to the high-dose methotrexate group, with fewer adverse reactions, better safety and tolerability, and may be a feasible regimen.