Prognostic Value of [ 18 F]FDG PET/CT in Multiple Myeloma Patients at the Time of Initial Diagnosis

To investigate newly diagnosed multiple myeloma (MM) patients and determine whether a combination of baseline [ 18 F]FDG-PET-derived parameters and clinical parameters would improve patient prognostication.

In this IRB-approved study, patients who underwent [ 18 F]FDG-PET/CT as part of their initial diagnostic workup for MM in our centre between 2018 and 2024 were included. Various [ 18 F]FDG-PET/CT parameters were extracted, including bone marrow, focal lesion, and total body measurements. Also, clinical parameters were gathered. The Cox proportional model was employed to estimate hazard ratios (HRs) for each parameter. A P -value <0.05 was considered statistically significant.

A total of 42 patients (mean age =67 y) entered this study. The median follow-up was 24 months. From continuous [ 18 F]FDG-PET/CT-derived parameters, total-body metabolic tumor volume (TMTV), total-body total lesion glycolysis (TTLG), and bone marrow SUVmax were found to be significantly correlated with patient survival. Following dichotomization, TMTV and TTLG lost their statistical significance, while bone marrow SUVmax retained its significance, showing an HR of 8.5 ( P = 0.039). Moreover, the presence of extramedullary disease was the other significant predictor of survival, with an HR of 5.5 ( P = 0.002). Among the continuous clinical parameters, serum free light chain ratio, β2-microglobulin, LDH, and creatinine levels significantly correlated with patient survival. Only serum β2-microglobulin retained its significance following dichotomization, showing an HR of 4.0 ( P = 0.015).

[ 18 F]FDG-PET/CT-derived parameters, particularly high bone marrow SUVmax and the presence of extramedullary disease, as well as their combination with clinical parameters, particularly high serum β2-microglobulin level, have the potential to enhance MM prognostication at the time of baseline staging.