The Role of [18F]FDG PET/MRI in Endometrial Cancer: Diagnostic and Prognostic Insights

The prospective [18F]FDG PET/MRI study shows exceptional preoperative staging performance, closing prior gaps in nodal detection and tumor characterization by integrating metabolic and anatomic data to refine risk stratification.

Conventional preoperative modalities often miss small nodal disease and lack molecular context, leaving risk classification incomplete. Hybrid PET/MRI consolidates anatomical, metabolic, and functional assessments into a single evaluation, potentially streamlining workflows and improving the information available for multidisciplinary planning.

Diagnostic performance was high: primary tumor detection accuracy was 98.75% and nodal involvement accuracy was 92.41%. These results come from a prospective cohort of 80 patients with imaging correlated to histopathology; sensitivity, specificity, and predictive values supported robust nodal assessment in a cohort with 17% node-positive disease.

Quantitative imaging features like contrast uptake, standardized uptake values (SUVs), and volumetric metrics correlated with molecular markers including p53 abnormalities and mismatch repair (MMR) deficiency. Associations were reported as moderate-to-fair (AUCs in the low- to mid-70% range), indicating useful noninvasive molecular stratification rather than established causal links.

Specific imaging-derived thresholds also carried prognostic information: a cranio-caudal diameter (Size_CC) ≥ 43 mm and metabolic tumor volume (MTV) ≥ 13.5 cm3 were associated with shorter disease-free survival and a higher recurrence probability than lower values. These cut points can flag patients for intensified surveillance or consideration of adjuvant planning while awaiting external validation.

Collectively, the diagnostic accuracy, molecular correlations, and prognostic thresholds position [18F]FDG PET/MRI to inform preoperative decision pathways by combining staging, molecular inference, and risk estimation into a single assessment. Next steps include targeted validation of thresholds, prospective incorporation into multidisciplinary workflows, and evaluation of downstream management impact.

Key Takeaways:

• High diagnostic accuracy for primary tumor and nodal staging supports PET/MRI as a comprehensive preoperative assessment tool.
• Imaging biomarkers provide moderate predictive ability for molecular risk phenotypes (AUCs ~70s) but require validation before replacing tissue-based assays.
• Defined volumetric/metabolic thresholds (Size_CC ≥ 43 mm; MTV ≥ 13.5 cm3) offer actionable signals for risk-adapted planning and prioritization for further study.