Diagnostic accuracy of MRI and PSMA PET/CT for detection of histologically confirmed lymph node metastasis in prostate cancer: A systematic review.

OBJECTIVE: To compare the diagnostic accuracy of prostate-specific membrane antigen positron emission tomography/computed tomography (PSMA PET/CT) and multiparametric magnetic resonance imaging (mpMRI) for the detection of histologically confirmed pelvic lymph node metastases in patients with intermediate- and high-risk prostate cancer. METHODS: A systematic review and meta-analysis were conducted according to PRISMA guidelines. PubMed, Embase, and Cochrane Library databases were searched from January 2011 to March 2026. Studies evaluating PSMA PET/CT and/or mpMRI for preoperative pelvic lymph node staging using histopathology as the reference standard were included. Study quality was assessed using the Quality Assessment of Diagnostic Performance Studies-2 tool (QUADAS-2). Pooled sensitivity and specificity were estimated using a hierarchical bivariate random- effects (Reitsma) model, and hierarchical summary receiver operating characteristic (HSROC) curves were generated. RESULTS: Sixteen studies comprising 1,999 patients met the inclusion criteria. Fourteen studies contributed to the PSMA PET/CT analysis and six studies to the mpMRI analysis. For PSMA PET/CT, pooled sensitivity was 54.6% (95% CI 43.7-65.1%) and pooled specificity was 92.7% (95% CI 90.5-94.4%). The HSROC area under the curve (AUC) was 0.909. For mpMRI, pooled sensitivity was 33.0% (95% CI 18.7-51.3%) and pooled specificity was 94.9% (95% CI 92.2-96.8%), with an HSROC AUC of 0.941. Indirect comparison of pooled estimates suggested that PSMA PET/CT had higher sensitivity and a higher diagnostic odds ratio than mpMRI. However, because these estimates were derived from separate bodies of evidence rather than direct head-to-head comparative studies, this comparison should be interpreted with caution. CONCLUSIONS: PSMA PET/CT demonstrated higher pooled sensitivity than mpMRI while maintaining similarly high specificity for detecting pelvic lymph node metastases. However, the moderate sensitivity of both imaging modalities indicates that a negative PSMA PET/CT scan cannot reliably exclude microscopic nodal disease. Furthermore, this comparison between pooled estimates should be interpreted with caution because it is based on an indirect comparison rather than a formal head-to-head meta-analysis. Consequently, extended pelvic lymph node dissection remains the reference standard for pathological nodal staging in appropriately selected patients, and prospective head-to-head comparative studies are required to define the relative diagnostic performance of PSMA PET/CT and mpMRI.