ObjectivesTo review the literature to determine the sensitivity and specificity of gallium-68 prostate-specific membrane antigen ( 68 Ga-PSMA) positron-emission tomography (PET) for detecting pelvic lymph node metastases in patients with primary prostate cancer (PCa), and the positive predictive value in patients with biochemical recurrence (BCR) after initial curative treatment, and, in addition, to determine the detection rate and management impact of 68 Ga-PSMA PET in patients with BCR after radical prostatectomy (RP). Materials and MethodsWe performed a comprehensive literature search. Search terms used in MEDLINE, EMBASE and Science Direct were '(PSMA, 68 Ga-PSMA, 68 Gallium-PSMA, Ga-68-PSMA or prostate-specific membrane antigen)' and '(histology, lymph node, staging, sensitivity, specificity, positive predictive value, recurrence, recurrent or detection)'. Relevant abstracts were reviewed and full-text articles obtained where possible. References to and from obtained articles were searched to identify further relevant articles. ResultsNine retrospective and two prospective studies described the sensitivity and specificity of 68 Ga-PSMA PET for detecting pelvic lymph node metastases before initial treatment, which ranged from 33.3% to 100% and 80% to 100%, respectively. In eight retrospective studies, the positive predictive value of 68 Ga-PSMA PET in patients with BCR before salvage lymph node dissection ranged from 70% to 100%. The detection rate of 68 Ga-PSMA PET in patients with BCR after RP in the PSA subgroups <0.2 ng/mL, 0.2-0.49 ng/mL and 0.5 to <1.0 ng/ mL ranged from 11.3% to 50.0%, 20.0% to 72.7% and 25.0% to 87.5%, respectively. ConclusionThe review results showed that 68 Ga-PSMA PET had a high specificity for the detection of pelvic lymph node metastases in primary PCa. Furthermore, 68 Ga-PSMA PET had a very high positive predictive value in detecting lymph node metastases in patients with BCR. By contrast, sensitivity was only moderate; therefore, based on the currently available literature, 68 Ga-PSMA PET cannot yet replace pelvic lymph node dissection to exclude lymph node metastases. In the salvage phase, 68 Ga-PSMA PET had both a high detection rate and impact on radiotherapy planning in early BCR after RP. Keywords 68Ga-PSMA PET/CT, pelvic lymph node dissection, detection rate, pelvic lymph node metastases, #ProstateCancer, #PCSM Use of 68Ga-PSMA PET/CT after RP: review IQR, interquartile range; LNM, lymph node metastases. *Gallium-68 prostate-specific membrane antigen positron-emission tomography ( 68 Ga-PSMA PET)/MRI was used instead of 68 Ga-PSMA PET/CT. 208

Purpose To investigate the effect of reader experience and zonal location on the occurrence of false positives (FPs) in PIRADS (V2) 3, 4, and 5 lesions on multiparametric (MP)-MRI of the prostate. Materials and methods This retrospective study included 139 patients who had consecutively undergone an MP-MRI of the prostate in combination with a transrectal ultrasound MRI fusion-guided biopsy between 2014 and 2017. MRI exams were prospectively read by a group of inexperienced radiologists (cohort 1; 54 patients) and an experienced radiologist (cohort 2; 85 patients). Multivariable logistic regression analysis was performed to determine the association of experience of the radiologist and zonal location with a FP reading. FP rates were compared between readings by inexperienced and experienced radiologists according to zonal location, using Chi-square (χ 2) tests. Results A total of 168 lesions in 139 patients were detected. Median patient age was 68 years (Interquartile range (IQR) 62.5-73), and median PSA was 10.9 ng/mL (IQR 7.6-15.9) for the entire patient cohort. According to multivariable logistic regression, inexperience of the radiologist was significantly (P = 0.044, odds ratio 1.927, 95% confidence interval [CI] 1.017-3.651) and independently associated with a FP reading, while zonal location was not (P = 0.202, odds ratio 1.444, 95% CI 0.820-2.539). In the transition zone (TZ), the FP rate of the inexperienced radiologists 59% (17/29) was significantly higher (χ 2 P = 0.033) than that of the experienced radiologist 33% (13/40). Conclusion Inexperience of the radiologist is significantly and independently associated with a FP reading, while zonal location is not. Inexperienced radiologists have a significantly higher FP rate in the TZ.

Objectives To investigate whether serial prostate magnetic resonance imaging (MRI) may guide the utility of repeat targeted (TBx) and systematic biopsy (SBx) when monitoring men with low‐risk prostate cancer (PCa) at 1‐year of active surveillance (AS). Patients and Methods We retrospectively included 111 consecutive men with low‐risk (International Society of Urological Pathology [ISUP] Grade 1) PCa, who received protocolled repeat MRI with or without TBx and repeat SBx at 1‐year of AS. TBx was performed in Prostate Imaging‐Reporting and Data System (PI‐RADS) score ≥3 lesions (MRI‐positive men). Upgrading defined as ISUP Grade ≥2 PCa (I), Grade ≥2 with cribriform growth/intraductal carcinoma PCa (II), and Grade ≥3 PCa (III) was investigated. Upgrading detected by TBx only (not by SBx) and SBx only (not by TBx) was investigated in MRI‐positive and ‐negative men, and related to radiological progression on MRI (Prostate Cancer Radiological Estimation of Change in Sequential Evaluation [PRECISE] score). Results Overall upgrading (I) was 32% (35/111). Upgrading in MRI‐positive and ‐negative men was 48% (30/63) and 10% (5/48) ( P < 0.001), respectively. In MRI‐positive men, there was upgrading in 23% (seven of 30) by TBx only and in 33% (10/30) by SBx only. Radiological progression (PRECISE score 4–5) in MRI‐positive men was seen in 27% (17/63). Upgrading (I) occurred in 41% (seven of 17) of these MRI‐positive men, while this was 50% (23/46) in MRI‐positive men without radiological progression (PRECISE score 1–3) ( P = 0.534). Overall upgrading (II) was 15% (17/111). Upgrading in MRI‐positive and ‐negative men was 22% (14/63) and 6% (three of 48) ( P = 0.021), respectively. In MRI‐positive men, there was upgrading in three of 14 by TBx only and in seven of 14 by SBx only. Overall upgrading (III) occurred in 5% (five of 111). Upgrading in MRI‐positive and ‐negative men was 6% (four of 63) and 2% (one of 48) ( P = 0.283), respectively. In MRI‐positive men, there was upgrading in one of four by TBx only and in two of four by SBx only. Conclusion Upgrading is significantly lower in MRI‐negative compared to MRI‐positive men with low‐risk PCa at 1‐year of AS. In serial MRI‐negative men, the added value of repeat SBx at 1‐year surveillance is limited and should be balanced individually against the harms. In serial MRI‐positive men, the added value of repeat SBx is substantial. Based on this cohort, SBx is recommended to be performed in combination with TBx in all MRI‐positive men at 1‐year of AS, also when there is no radiological progression.

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