Impact of Postoperative Chemotherapy on Survival in Patients with Primary Central Nervous System Lymphoma: A Study Based on the SEER Database

<b>Aims/Background</b> We aimed to investigate the impact of postoperative chemotherapy (POCT) on survival in patients with primary central nervous system lymphoma (PCNSL) using data from the Surveillance, Epidemiology, and End Results (SEER) database. <b>Methods</b> This study included 786 PCNSL patients, of which 605 received chemotherapy after surgery, and 181 did not. Data from the SEER registry database (2007-2020) were used to analyze PCNSL. Baseline information, including age, sex, race, marital status, primary tumour site, histological type, summary stage, surgical procedures, chemotherapy, and radiotherapy, was analyzed. Propensity Score Matching (PSM) (1:1) was employed to balance the effects of confounding variables between the two groups. Subsequently, Cox regression and bidirectional stepwise regression were used to identify independent prognostic factors. Kaplan-Meier (K-M) survival curves were constructed to assess the impact of POCT on patient prognosis. Additionally, two cases of PCNSL with typical magnetic resonance imaging appearances were presented. <b>Results</b> Multivariate Cox regression results revealed that age older than 60 years (hazard ratio [HR] = 1.786; 95% confidence interval [CI]: 1.272-2.509; <i>p</i> = 0.001) and absence of POCT (HR = 2.841; 95% CI: 2.159-3.738; <i>p</i> < 0.001) were independent prognostic risk factors, while primary tumour locations in the meninges (HR = 0.136; 95% CI: 0.032-0.569; <i>p</i> = 0.006) and other nervous system regions (HR = 0.552; 95% CI: 0.326-0.936; <i>p</i> = 0.027), as well as histological morphologies such as diffuse large B-cell lymphoma (HR = 0.233; 95% CI: 0.128-0.425; <i>p</i> < 0.001) and non-Hodgkin lymphoma (HR = 0.559; 95% CI: 0.356-0.876; <i>p</i> = 0.011), were associated with favourable patient outcomes. K-M curves demonstrated that the group undergoing POCT had a significantly more favourable prognosis compared to the non-POCT group, before (HR = 0.454; 95% CI: 0.343-0.600; <i>p</i> < 0.0001) or after PSM (HR = 0.580; 95% CI: 0.431-0.780; <i>p</i> < 0.0001). For patients with PCNSL, those with tumours located in the infratentorial region (HR = 0.231; 95% CI: 0.078-0.682; <i>p</i> = 0.046), supratentorial region (HR = 0.250; 95% CI: 0.163-0.383; <i>p</i> < 0.0001), overlapping brain regions (HR = 0.201; 95% CI: 0.056-0.727; <i>p</i> = 0.0058), and those who underwent biopsy (HR = 0.740; 95% CI: 0.463-1.182; <i>p</i> = 0.003), subtotal resection (STR) (HR = 0.490; 95% CI: 0.265-0.906; <i>p</i> = 0.0064), or gross total resection (GTR) (HR = 0.613; 95% CI: 0.292-1.287; <i>p</i> = 0.0003) had better prognoses in the postoperative chemotherapy group compared to the non-chemotherapy group. <b>Conclusion</b> POCT significantly improves the prognosis of PCNSL patients and identifies the characteristics of the benefiting population. This information aids clinical practitioners in designing personalized treatment plans for individuals and advancing precise treatment.