Apparent diffusion coefficient as a valuable quantitative parameter for predicting clinical outcomes in patients with newly diagnosed primary CNS lymphoma.

Abstract

e14532 Background: Primary central nervous system lymphoma (PCNSL) is a rare subtype of non-Hodgkin lymphoma (NHL). Although, there are various treatment options for PCNSL which include methotrexate based chemotherapy and whole brain radiotherapy (WBRT), half of the patients who initially achieved complete response experience disease relapse. Accordingly, we attempted to identify novel prognostic factors using MRI in patients with newly diagnosed PCNSL. Methods: We retrospectively evaluated 672 patients who were diagnosed with central nervous system (CNS) cancers between January 2011 and May 2018. Enrollment criteria were i) pathologic diagnosis of CNS lymphoma, ii) no evidence of systemic involvement, iii) no evidence of human immunodeficiency virus-1 infection or other immunodeficiencies, and iv) available magnetic resonance imaging (MRI) examinations at diagnosis. Fifty-two patients met these criteria and were enrolled. Results: Patients with low apparent diffusion coefficient (ADC) showed inferior overall survival (OS) compared to those with high ADC. Patients with a hyperintense signal on T2-weighted image and homogenous enhancement showed better failure-free survival (FFS), while patients with low ADC and necrosis showed poor FFS. In the multivariate survival analysis, old age ( > 60) (hazard ratio (HR) 20.372, p= 0.001), Eastern Cooperative Oncology Group performance status ((ECOG PS) ≥ 2 (HR 10.429, p < 0.001), higher levels of lactate dehydrogenase (LDH) (HR 7.408, p= 0.001), and low ADC (HR 0.273, p= 0.009) were associated with inferior OS, while ECOG PS ≥ 2 (HR 10.319, p= 0.021), presence of necrosis (HR 6.372, p= 0.008), and low ADC (HR 0.226, p= 0.020) were unfavorable factors for FFS. Conclusions: We conclude that ADC, a characteristic MRI finding, had significant prognostic value for long-term survival in our study of patients with newly diagnosed PCNSL Specifically, low ADC was an independent unfavorable prognostic factor, suggesting that ADC measurements through non-invasive MRI can improve the current prognostic scoring system.