Can metabolic tumour parameters on primary staging 18F-FDG-PET/CT contribute to risk stratification of primary central nervous system lymphomas for patient management as a prognostic model?

Abstract

ObjectivePrimary central nervous system (CNS) lymphoma is an aggressive and fatal extranodal non-Hodgkin lymphoma (NHL) jailed in CNS at initial diagnosis. Its prognosis is poor and the disease has a fatal outcome when compared with systemic NHL. A few baseline risk stratification scoring systems have been suggested to estimate the prognosis mainly based on serum lactate dehydrogenase (LDH) level, age, Karnofsky performance score (KPS), involvement of deep brain structures (DBS) and cerebrospinal fluid protein concentration. 18F-FDG-PET/CT has a high prognostic value with respect to overall survival (OS) and disease-free survival (DFS) in many cancers and lymphomas. We aimed to investigate metabolic tumour indexes on primary staging 18F-FDG-PET/CT as prognostic markers in primary CNS lymphoma. Material and methods14 patients with primary CNS diffuse large B-cell lymphoma (stage I) were enrolled in this retrospective cohort study. Primary staging 18F-FDG-PET/CT was performed and quantitative parameters like maximum standardized uptake value (SUVmax), average standardized uptake value (SUVmean), metabolic tumour volume (MTV) and total lesion glycolysis (TLG) were calculated for all patients before the treatment. Cox regression models were performed to determine their relation with survival time. ResultsIn the evaluation of all potential risk factors impacting recurrence/metastases (age, sex, serum LDH, involvement of DBS, SUVmax, SUVmean, MTV, TLG) with univariate analysis, TLG remained statistically significant (p=0.02). ConclusionMetabolic tumour parameters are useful in prognosis estimation of primary CNS lymphomas, especially TLG, which is the most important one and may play a role in patient management.