A prospective cohort study of methotrexate plus idarubicin in newly diagnosed primary CNS lymphoma

Purpose High-dose methotrexate (HD-MTX)-based chemotherapy regimen is the first-line option for primary central nervous system lymphoma (PCNSL). This prospective cohort study aimed to evaluate the efficacy and adverse effects of HD-MTX plus idarubicin (IDA) in patients with newly diagnosed immunocompetent PCNSL. Methods We recruited newly diagnosed PCNSL patients from January 2017 to August 2020. Patients were assigned into two groups: HD-MTX monotherapy and HD-MTX plus IDA (HD-MTX/IDA). In the HD-MTX monotherapy group, patients were treated with MTX 8 g/m 2 alone on day 1, while the HD-MTX/IDA group received MTX 8 g/m 2 on day 1 and IDA 10 mg/m 2 on day 2. Treatments were repeated every 3 weeks for 8 cycles except for progression and/or unacceptable toxicity. Results We recruited 61 PCNSL patients, including 36 in the HD-MTX and 25 in the HD-MTX/IDA group. The CR rate was 68% in the HD-MTX/IDA group and 72.22% of patients in the HD-MTX monotherapy group (p = 0.7221), while the overall response rate was 72% vs. 77.78% (p = 0.6063). Median PFS in HD-MTX/IDA group and HD-MTX monotherapy group were 15.6 months and 18.5 months, respectively (p = 0.6374). Median OS was not reached in both groups. There were no significant differences in adverse effects between the two groups. Conclusions The combination of IDA with HD-MTX showed no obvious therapeutic advantage over HD-MTX monotherapy in newly diagnosed patients with PCNSL. HD-MTX dose of 8 g/m 2 monotherapy can still provide better therapeutic benefits in patients with acceptable adverse effects. Future studies could explore HD-MTX in combination with other chemotherapeutic agents in the first-line treatment of PCNSL.