Both consolidation and maintenance treatment improve outcomes in primary central nervous system lymphoma: real-world evidence from a tertiary medical center

<b>Background:</b> Intensive consolidation treatment following high-dose methotrexate (HDMTX)-based chemotherapy is recommended for fit patients with primary central nervous system lymphoma (PCNSL). Otherwise, HDMTX maintenance might be a useful alternative to consolidation approach in certain circumstances. However, the real-world evidence supporting the beneficial role of consolidation treatment or HDMTX maintenance in PCNSL is limited. <b>Methods:</b> We retrospectively analyzed the clinical efficacy and survival impact of consolidation treatment or HDMTX maintenance on patients with PCNSL treated with HDMTX-based induction chemotherapy. <b>Results:</b> A total of 109 patients were evaluated, with a median age at diagnosis being 63 years. Among them, 69 received induction therapy with HDMTX monotherapy and 40 with HDMTX-based polychemotherapies. In total, 67 (61.5%) patients responded to treatment, of whom 56 (51.4%) had complete response. After a 58.9-month median follow-up, overall survival (OS) at 2 and 5 years was 69% and 45%, respectively. The types of induction regimen or frontline rituximab had no survival impact (<i>P</i> = 0.364 and 0.328, respectively). Among the 67 responding patients, 51 received the consolidation/maintenance therapy. Compared to the patients without consolidation/maintenance, those being treated had lower relapse/PD rates (2-year cumulative incidence of relapse/PD, 39.5% vs. 63.6%, <i>P</i> <0.001) and a significantly better OS (5-year survival rate, 63.8% vs. 27.2%, <i>P</i> = 0.016). Multivariate analysis revealed consolidation/maintenance treatment strikingly reduced mortality risk. Notably, HDMTX maintenance had similar efficacy comparable to consolidative whole-brain radiotherapy. Moreover, consolidation treatment was conducive to prolonging remission duration in the later-line settings of patients who responded to subsequent salvage therapies. <b>Conclusion</b>: This real-world evidence provides clear insight that consolidation/maintenance treatment could prolong OS in PCNSL, emphasizing its critical and indispensable role in treating PCNSL.