Findings from positron emission tomography-computed tomography (PET-CT) with prostate-specific membrane antigen (PSMA) may identify men with prostate cancer who can avoid pelvic lymph node dissection (PLND), investigators suggest.
Current nomograms identify patients at increased risk for lymph node invasion (LNI). Results from extended PLND show that only 30% of these patients have lymph node metastasis, according to background information. Therefore, 70% of PLNDs appear to be avoidable.
Armando Stabile, MD, of IRCCS Ospedale San Raffaele, Milan, Italy, and colleagues assessed the performance of PSMA PET/CT in detecting LNI in a systematic review of 27 studies including 2832 men with newly diagnosed prostate cancer. Each patient’s preoperative PSMA PET/CT imaging results were compared against histology findings from extended PLND during radical prostatectomy.
For each patient, the diagnostic accuracy of PSMA PET/CT was 84% estimated through summary receiver operating characteristic-derived area under the curve. Per node, the negative predictive value (NPV) of PSMA PET/CT was 97%, the investigators reported in European Urology Oncology.
The overall sensitivity, specificity, positive predictive value (PPV), and NPV of PSMA PET/CT for LNI were 58%, 95%, 79%, and 87%, respectively. Among patients with high-risk disease, its sensitivity, specificity, PPV, and NPV were 51%, 93%, 73%, and 81%, respectively.
As the prevalence of LNI increased from 5% to 40%, PPV increased from 59% to 91%, whereas NPV decreased from 99% to 84%.
“PSMA PET/CT scan provides promising accuracy in the field of primary nodal staging for [prostate cancer],” according to Dr Stabile’s team. “The high NPV in men with a lower risk of LNI might be clinically useful to reduce the number of unnecessary PLND procedures performed. Conversely, in high-risk patients, negative PSMA PET/CT cannot replace staging ePLND.”
Further studies are needed to test PSMA PET/CT’s utility for primary staging and cost-effectiveness.
Stabile A, Pellegrino A, Mazzone E, et al. Can negative prostate-specific membrane antigen positron emission tomography/computed tomography avoid the need for pelvic lymph node dissection in newly diagnosed prostate cancer patients? A systematic review and meta-analysis with backup histology as reference standard. Eur Urol Oncol. 5(1):1-17.