Does lymph node localization affect prostate-specific membrane antigen uptake?

Area of Science:

• Oncology
• Radiology
• Nuclear Medicine

Background:

• Prostate-specific membrane antigen (PSMA) Positron Emission Tomography/Computed Tomography (PET/CT) is crucial for staging prostate cancer.
• Understanding factors influencing PSMA uptake in lymph nodes (LNs) can improve diagnostic accuracy.

Purpose of the Study:

• To investigate the relationship between lymph node (LN) size and localization and prostate-specific membrane antigen (PSMA) uptake in prostate cancer patients.
• To determine if LN size and location impact PSMA uptake, aiding in metastasis detection.

Main Methods:

• Retrospective analysis of 178 prostate adenocarcinoma patients undergoing gallium-68 PSMA PET/CT.
• Seventy-eight patients with LN PSMA uptake were analyzed for short-axis diameter and SUV.
• LNs were categorized by size, localization (pelvic, abdominal, cervical/thoracic), and presence/absence of bone metastasis.

Main Results:

• Significantly higher SUV in LNs >8 mm compared to those ≤8 mm (P < 0.001).
• Moderate correlation observed between LN size and SUV in both groups.
• Excluding conglomerates, pelvic and abdominal LNs showed a higher size-SUV correlation in patients without bone metastasis.

Conclusions:

• A significant positive correlation exists between LN size and SUV in prostate cancer patients with pelvic and abdominal LN metastases.
• This correlation is strongest in the absence of bone involvement, suggesting size and location are key indicators of PSMA uptake in specific metastatic patterns.