Impact of treatment variability on survival in immuno-competent and immuno-compromised patients with primary central nervous lymphoma.

Patients with primary central nervous system lymphoma (PCNSL) treated in the 'real-world' setting do not represent those treated on clinical trials and might not be treated similarly. We studied characteristics and variability in care for 113 newly diagnosed PCNSL patients treated at 5 institutions in the Chicago area between 2000 and 2012. In 111 patients, single modality therapy with a high dose methotrexate (HD-MTX) regimen +/- rituximab, was most commonly employed (n = 65), and 34 underwent radiotherapy (+/- systemic therapy). Fifty-eight of 108 patients received rituximab. Twenty-nine of 110 patients (26%) received intrathecal chemotherapy (ITC). Overall response rate was 80% (47% complete responses). With a median follow-up of 18·7 months, median overall survival (OS) was 65·2 months. In univariate analysis, HD-MTX (median OS 72·7 vs. 2·7 months, P < 0·001) and rituximab (median not reached versus 28·4 months, P = 0·005) impacted OS favourably. This significance was sustained regardless of immune status and in multivariate analysis. Whole brain radiotherapy (WBRT) resulted in a trend for improved OS as compared with systemic therapy alone (P = 0·09), while ITC did not impact survival. Clinical practice has evolved to exclude WBRT and ITC while incorporating rituximab with clinical outcomes comparable in immuno-competent/compromised patients and similar to those achieved in recent clinical trials.