Primary treatment and Recent survival trends in patients with Primary Diffuse Large B-Cell Lymphoma of Central Nervous System,1995-2016: a population-based SEER analysis

This retrospective cohort study aimed to evaluate primary treatment and recent survival trends in patients with primary diffuse large B-cell lymphoma of CNS from 1995 to 2016.Using the SEER data, patients diagnosed with non-HIV associated PCNSL-DLBCL aged ⩾18 years between 1995 and 2016 were identified. The year of diagnosis was divided into the time periods-1(1995–2002), the time periods-2(2003–2012) and the time periods-3(2013–2016). We used Chi-square tests, the Kaplan–Meier method, log-rank test and Cox regression model in the analysis. Overall, 3760 patients were included. Both the use of radiotherapy alone and the application of combined chemoradiotherapy decreased significantly, following the wider use of chemotherapy alone during 1995–2016. There was a significant improvement in PCNSL cancer-specific survival (period-1: 13 months vs period-2: 19 months vs period-3: 41 months, P  < 0.001). Survival of patients aged above 70 years did not change from the time period-1 to the time period-2 ( P  = 0.101). However, there was an increase in CSS from the time period-2 to the time period-3 in the elderly patients (period-2: 5 months vs period-3: 9 months, P  < 0.001). On multivariable analyses, diagnosed in the time period-3 was significantly and independently associated with better CSS (HR 0.577, 95% CI 0.506–0.659). Our analysis shows the use of radiotherapy in the treatment of PCNSL has waned over the study span. There was a significant improvement in CSS during 1995–2016, which reflected developments in treatment over time. The elderly patient population also gained a significant CSS benefit in the most recent period.