Abstract Background This study aimed to identify prognostic factors in patients with newly diagnosed primary central nervous system lymphoma (PCNSL) treated with high-dose methotrexate–based therapy and to develop a novel risk-stratification model using easily measurable clinical and laboratory parameters. Methods A total of 451 patients with newly diagnosed PCNSL were identified from a prospective registry at Asan Medical Center, Seoul. Patients were randomly assigned to a training cohort (n = 280; October 2002–August 2019) and an independent validation cohort (n = 171; September 2019–December 2023). Results With a median follow-up of 106.0 months (95% CI, 101.0–120.0), the median overall survival (OS) in the training cohort was 46.1 months (95% CI, 34.9–57.6). Independent predictors of worse OS (p 0.05) included age ≥65 years, high serum β2-microglobulin levels (≥1.8 mg/L), elevated serum lactate dehydrogenase, and ECOG performance status 1. These four factors were combined to form the ABLE score, which stratified patients into low- (0 risk factors), intermediate- (1 risk factor), and high-risk (≥2 risk factors) groups. In the training cohort, median OS was 109.0, 49.0, and 18.0 months, respectively (p 0.001). Validation in the independent cohort confirmed significant prognostic discrimination, with median OS of not reached, 53.1, and 19.0 months for each risk group (p 0.001). Comparative analyses demonstrated that the ABLE model showed improved discrimination compared with existing systems. Bootstrap validation (n = 451) yielded an optimism-corrected C-index of 0.656 (95% CI, 0.628–0.685). Conclusions The ABLE risk-stratification model can effectively differentiate prognostic subgroups in patients with PCNSL.
Shin et al. (Mon,) studied this question.