Beta-2 microglobulin as a diagnostic parameter in non-Hodgkin lymphoma: a comparative study with FDG-PET

The aim of this study was to determine the diagnostic value of the serum tumor marker beta-2 microglobulin (β2M) as well as positron emission tomography (PET) using (18)F-fluorodeoxyglucose (FDG) in confirming or eliminating the diagnosis of non-Hodgkin lymphoma (NHL).

Retrospective analysis of 180 patients with NHL referred for a PET scan was performed. Patients' data regarding demographic information, clinical history, and diagnostic procedures were collected. The sensitivity, specificity, and positive/negative predictive value of serum β2M levels and FDG-PET, compared to a compound gold standard consisting of imaging modalities (computed tomography, magnetic resonance tomography, ultrasound) and/or biopsy, were assessed and compared.

β2M had a sensitivity and specificity of 49% and 52% for all types and settings, respectively, as well as a low positive predictive value (66%) and a very low negative predictive value (36%). The overall sensitivity and specificity of FDG-PET for all types of NHL in all settings was 87% and 92%, respectively.

Due to its low sensitivity and specificity, β2M cannot be used in the clinical routine as a diagnostic marker for the diagnosis of NHL. On the other hand, in accordance with previous studies, we found that FDG-PET is an excellent tool for the diagnosis of NHL.