Objective  To analyze the clinical characteristics of patients with relapsed/refractory primary central nervous system lymphoma (PCNSL) and to explore the factors that influence the prognosis, in order to provide evidence for the clinical diagnosis and treatment.

  Methods  Sixty-four patients with relapsed/refractory PCNSL diagnosed from October 2006 to August 2015 were selected. The clinical features, treatment plans, and laboratory examination data were retrospectively analyzed. Cox regression was used for multivariate analysis.

  Results  Univariate and multivariate analyses showed that progression-free survival of first time (PFS1)≤1 year and Karnofsky performance status (KPS) score < 70 points were independent prognostic factors in patients with first relapsed/refractory PCNSL. The median PFS2 and overall survival of second time (OS2) were 19 and 21 months, respectively, in patients with PFS1≥1 year, whereas the median progression free survival of second time (mPFS2) and OS2 were 10 and 14 months, respectively, in patients with PFS1 < 1 year. The median PFS2 (mPFS2) in patients with first relapse/refractory KPS score ≥70 points and those with KPS score < 70 points were 40 and 10 months, respectively, and the median OS2 were 43 and 12 months, respectively. The median PFS for the methotrexate (MTX) and non-MTX groups was 18 and 10 months, respectively. Multivariate analysis showed that the salvage therapy was a relevant factor influencing the patient's PFS. However, univariate analysis showed that the median OS2 in the MTX and non-MTX groups was 23 and 12 months, respectively, with significant difference but without any correlation with prognosis.

  Conclusions  progression-free survival (PFS)≤1 year and KPS score < 70 were independent prognostic factors in patients with first relapsed/refractory PCNSL. Patients with relapsed/refractory PCNSL who continuously received high-dose MTX-based treatment may have improved long-term treatment outcomes.