Increased Sensitivity in the Detection of Lymph Node Metastases in Biochemical Relapse of Prostate Cancer with 18F PSMA PET/CT, Respect to Computed Axial Tomography

• Areas of Interest: Theragnostics

Background: This study aimed to evaluate the diagnostic sensitivity, considering increased uptake with 18F PSMA in lymph nodes that measure 10 mm or less by CT, a value that is used as a cut-off to consider lymph nodes as pathological by this method.

Methods: We evaluated 85 patients who underwent 18F PSMA 1007 PET/CT for biochemical relapse in Prostate cancer. A dose of 0.10 mCi/Kg, the images were taken 90 minutes after injection.

Results: Of the 85 patients studied, 28 (36.94%) presented pelvic lymph node metastases, detecting 94 pelvic lymph node lesions of which 62 lymph nodes (65.95%) were less than or equal to 1 cm in their longer axis. Of the patients with pelvic lymph node metastases, 11 were oligometastatic (39.28%) which implies an important change in therapeutic behavior and especially in survival. Also, 22 patients (25.88%) had distant hypermetabolic nodes, a total of 51 hypermetabolic nodes, at least 35 (68.63%) of them measured 10 mm or less. It is noteworthy that it was not possible to carry out biopsy verification in most of our patients, due to ethical and practical reasons; however, in the situation of a clear biochemical relapse, we believe that 18 FPSMA is of great diagnostic value.

Conclusion: 18F PSMA 1007 demonstrates its efficacy in locating pelvic lymph node metastases in 36.94% and distant lymph node metastases in 25.88%, with a total of 145 nodes hypermetabolic of which 97 (66.98%) measured 10 mm or less, making 18 FPSMA an invaluable diagnostic tool.

Publication History

Article published online:
10 May 2022