Differentiating Reactive Lymph Nodes from Bladder Cancer Lymph Node Metastasis Using Dual Time Point 18F-FDG PET/CT Imaging - Expert Commentary

Differentiating reactive lymph nodes from lymph node bladder cancer metastasis through imaging is an area of unmet need that affects clinical management. A recent study by Zhou et al. examined the utility of dual time-point 18F-FDG PET/CT imaging to address this problem.

These investigators examined 250 lymph nodes from 153 patients, aiming to enhance diagnostic accuracy for more informed treatment decisions. The study showed that delayed PET/CT imaging, with cutoff SUVmax values of 2.0 and 2.5, increased the detection rate of metastatic lymph nodes by 4.1% and 6.9%, respectively. Moreover, the delayed imaging revealed speckle-like radioactive foci in nodes with reactive hyperplasia compared to more homogeneous FDG uptake in metastatic nodes.
A multivariable logistic regression analysis showed that lymph node short-axis diameter, SUVmean, and the delayed index of metabolic tumor volume (DIMTV) were independent predictors for distinguishing between metastatic and reactive nodes. DIMTV emerged as the most potent predictor, with an odds ratio (OR) of 4.242 of lymph node metastasis. The area under the curve (AUC) for the combination of short-axis diameter, SUVmean, and DIMTV in receiver operating characteristic (ROC) analysis were high at 0.938 demonstrating excellent sensitivity (82.8%) and specificity (89.5%) for predicting lymph node metastasis.
This study shows the potential of dual time-point 18F-FDG PET/CT imaging in bladder cancer for differentiating between lymph node metastasis and reactive hyperplasia. Integrating metabolic imaging parameters is a promising area of research.

Written by: Bishoy M. Faltas, MD, Director of Bladder Cancer Research, Englander Institute for Precision Medicine, Weill Cornell Medicine

References:

  1. Zhou X, Lu Z, Zhang R, Zhang R, Huang G, Shi K, Chen H, Liu J. 38431484 The Value of Dual Time Point (18)F-FDG PET/CT Imaging in Differentiating Lymph Node Metastasis From Reactive Hyperplasia in Bladder Urothelial Carcinoma. Acad Radiol. 2024 Mar 1:S1076-6332(24)00085-0. doi: 10.1016/j.acra.2024.02.014. Online ahead of print.
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