Refining PET-based response in extramedullary multiple myeloma using total lesion glycolysis

Area of Science:

• Nuclear Medicine
• Oncology
• Medical Imaging

Background:

• Positron Emission Tomography (PET) is crucial for assessing treatment response in multiple myeloma (MM) with extramedullary disease (EMD).
• The prognostic utility of PET-based metrics, specifically in EMD, requires further systematic investigation.

Purpose of the Study:

• To evaluate the role of FDG PET/CT imaging in assessing metabolic response in patients with MM and EMD.
• To compare the prognostic value of visual Deauville Scores (DS) and Total Lesion Glycolysis (TLG) for predicting outcomes in EMD.

Main Methods:

• Retrospective analysis of 95 patients with EMD undergoing FDG PET/CT.
• Assessment of metabolic response using visual Deauville Scores (DS) and quantitative Total Lesion Glycolysis (TLG).
• Categorization of TLG response into complete metabolic response (CMR), major metabolic response (MMR), and non-significant metabolic response (NMR).

Main Results:

• Significant differences in progression-free survival (PFS) and overall survival (OS) were observed for both DS and TLG response categories.
• TLG demonstrated superior discrimination compared to DS, with approximately one-third of patients reclassified by TLG stratification.
• TLG response was an independent prognostic factor for PFS in multivariable analysis, even after adjusting for cytogenetics, triple-class refractoriness, and de novo EMD status.

Conclusions:

• Total Lesion Glycolysis (TLG) offers enhanced prognostic value over visual Deauville Scores for patients with MM and EMD.
• The findings support the integration of TLG into response assessment criteria for EMD in multiple myeloma.
• FDG PET/CT quantitative metrics like TLG are essential for precise response evaluation and outcome prediction in EMD.