Diagnostic Accuracy of [18F]-DCFPyL Prostate-Specific Membrane Antigen Positron Emission Tomography/Computerized Tomography in Intermediate-Risk Prostate Cancer Undergoing Radical Prostatectomy: Is Pelvic Lymph Node Dissection Still Necessary?

Abstract

Purpose: Pelvic lymph node dissection (PLND) remains standard for nodal staging in prostate cancer (PCa), yet its benefit in intermediate-risk PCa is controversial. Traditional imaging and nomograms often lack accuracy, resulting in unnecessary PLND. Prostate-specific membrane antigen (PSMA) positron emission tomography (PET)/CT is a promising alternative. We compared its diagnostic performance and clinical utility with established risk models in intermediate-risk PCa.

Materials and methods: We analyzed patients with intermediate-risk PCa who underwent [¹⁸F]-DCFPyL PSMA PET/CT and radical prostatectomy with bilateral PLND between January 2022 and December 2023. PSMA PET/CT results were classified as positive or negative for nodal involvement. Diagnostic performance was compared with multiparametric MRI, the Briganti 2012, Briganti 2023 nomograms, and the Memorial Sloan Kettering Cancer Center nomogram by sensitivity, specificity, positive predictive value, negative predictive value, accuracy, balanced accuracy, and AUC.

Results: Among 189 patients, 28 (15%) had PSMA-positive lymph nodes. Pathology confirmed metastases in 4 PSMA-positive patients (positive predictive value: 14%, 95% CI: 7.1%-22%) and 1 PSMA-negative patient (negative predictive value: 99%, 95% CI: 98%-100%). PSMA PET/CT demonstrated 80% sensitivity (95% CI: 40%-100%), 87% specificity (95% CI: 82%-91%), balanced accuracy of 83% (95% CI: 63%-95%), and an AUC of 0.83 (95% CI: 0.64-1), outperforming other models. PSMA would have safely omitted PLND in 160 of 161 (99%) PSMA-negative cases, whereas multiparametric MRI detected no positive nodes.

Conclusions: PSMA PET/CT, with high specificity and negative predictive value, may safely guide PLND omission in PSMA-negative patients. Prospective validation is warranted.

Keywords: PET/CT; PSMA; intermediate-risk; lymph node dissection; prostate cancer.