Clinical impact of Prostate-Specific Membrane Antigen Positron Emission Tomography (PET) on intensification or deintensification of advanced renal cell carcinoma management.

PURPOSE: There is an emerging role of the use of Prostate-Specific Membrane Antigen (PSMA) Positron Emission Tomography (PET) in renal cell carcinoma. Herein, we report our experience in use of PSMA PET in recurrent or metastatic renal cell carcinoma (RCC). METHODS: A retrospective analysis of all patients who underwent PSMA PET for suspected recurrent or de-novo metastatic RCC between 2015 and 2020 at three institutions was performed. The primary outcome was change in management (intensification or de-intensification) following PSMA PET scan. Secondary outcomes included histopathological correlation of PSMA avid sites, comparison of sites of disease on PSMA PET to diagnostic CT and time to systemic treatment.

Etiology and management of urethral calculi: A systematic review of contemporary series.

Objective: To conduct a systematic literature review on urethral calculi in a contemporary cohort describing etiology, investigation, and management patterns. Methods: A systematic search of MEDLINE and Cochrane Central Register of Controlled Trials (CENTRAL) databases was performed. Articles, including case reports and case series on urethral calculi published between January 2000 and December 2019, were included. Full-text manuscripts were reviewed for clinical parameters including symptomatology, etiology, medical history, investigations, treatment, and outcomes. Data were collated and analyzed with univariate methods. Results: Seventy-four publications met inclusion criteria, reporting on 95 cases. Voiding symptoms (41.1%), pain (40.0%), and acute urinary retention (32.6%) were common presenting features. Urethral calculi were most often initially investigated using plain X-ray (63.2%), with almost all radio-opaque (98.3%). Urethral calculi were frequently associated with coexistent bladder or upper urinary tract calculi (16.8%) and underlying urethral pathology (53.7%) including diverticulum (33.7%) or stricture (13.7%). Urethral calculi were most commonly managed with external urethrolithotomy (31.6%), retrograde manipulation (22.1%), and endoscopic in situ lithotripsy (17.9%). Conclusion: This unique systematic review of urethral calculi provided a summary of clinical features and treatment trends with a suggested treatment algorithm. Management in contemporary urological practice should be according to calculus size, shape, anatomical location, and presence of urethral pathology.

The Role of Prostate-specific Membrane Antigen Positron Emission Tomography/Computed Tomography in Primary Staging of Selected Renal Tumours: Initial Experience in a Multicentre Cohort.

BACKGROUND: Accurate primary staging of renal cancer with conventional imaging is challenging. Prostate-specific membrane antigen (PSMA) positron emission tomography/computed tomography (PET/CT) may serve to improve the accuracy of renal cancer staging. OBJECTIVE: To determine clinicopathological and management differences for primary renal cancer staged with PSMA PET/CT in comparison to conventional imaging. DESIGN, SETTING, AND PARTICIPANTS: We conducted a retrospective cohort study of PSMA PET/CT scans performed for primary staging of renal cancer and incidental renal lesions at three sites in Brisbane, Australia between June 2015 and June 2020. Clinical characteristics, imaging, and histopathology were reviewed. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: Clinicopathological and management differences according to staging modality (PSMA PET/CT, conventional imaging) were assessed. Descriptive statistics were used to report demographics and clinical parameters. Nonparametric methods were used for statistical analysis. Fisher's exact test was used for comparison of small-cell size categorical variables. RESULTS AND LIMITATIONS: From a total of 120 PSMA PET/CT scans, 61 were included (52 staging, 9 incidental) for predominantly males (74%) with a mean age of 65.1 yr (standard deviation 12.0). Most primary lesions (40/51) were clear-cell renal cell carcinoma (ccRCC; 98% PSMA-avid), eight were non-ccRCC (75% PSMA-avid), and three were non-RCC (oncocytoma; 67% PSMA-avid). PSMA PET identified a greater number of presumed metastatic lesions than conventional imaging (195 vs 160). A management change was observed for 32% of patients (20% major, 12% minor). Limitations include the retrospective design and selection bias, lack of blinding to PSMA reporting, and the use of different PSMA radiotracers. CONCLUSIONS: PSMA PET/CT detected more metastases than conventional imaging and most renal cancers were PSMA-avid, resulting in a management change for one-third of the patients. PATIENT SUMMARY: We looked at a newer type of scan called PSMA PET/CT for first staging of kidney cancer. We found that this detects more metastasis and helps in decisions on changes in treatment for some patients. This type of imaging is a useful addition to conventional scans in tricky cases and may help in better selection of suitable treatments, but more studies are required.

Periurethral abscess etiology, risk factors, treatment options, and outcomes: A systematic review.

Objectives: This study aimed to describe patterns of presentation, etiology, risk factors, management, and treatment outcomes of periurethral abscesses using a systematic review framework. Materials and methods: After prospective registration on the PROSPERO database (CRD42020193063), a systematic review of Web of Science, Embase, PubMed, and Cochrane scientific databases was performed. Articles published between 1900 and 2021 were considered. Extracted data included symptoms, etiology, medical history, investigations, treatment, and outcomes. Collated data were analyzed using univariate methods. Results: Sixty articles met the inclusion criteria reporting on 270 patients (211 male, 59 female) with periurethral abscess. The most common clinical features were pain (41.5%), pyuria (41.5%), dysuria (38.5%), urinary frequency (32.3%), fever (25%), and a palpable mass (23%). Predisposing risk factors included the presence of a sexually transmitted infection or urinary tract infection (55.0%), urethral strictures (39.6%), and recent urethral instrumentation (18.7%). Management approaches included open incision and drainage (64.3%), conservative management with antibiotics (29.8%), and minimally invasive techniques (needle aspiration, endoscopic drainage). Time trend analysis of etiology revealed a decreased incidence of infection (sexually transmitted infection/urinary tract infection, human immunodeficiency virus) and higher incidence of diabetes mellitus and periurethral bulking injections in recent years. Conclusions: Periurethral abscesses may display a wide range of clinical features. Presentation, risk factors and underlying etiology vary with sex. The optimal management technique is guided by abscess size. Open incision and drainage combined with antibiotics continues to be the mainstay of management. However, minimally invasive techniques are gaining favor. To the authors' knowledge, this is the first systematic appraisal and management algorithm for periurethral abscess.

Pituitary Metastasis of Renal Cell Carcinoma Characterized by 18F-Prostate-Specific Membrane Antigen-1007 PET/CT.

ABSTRACT: Renal cell carcinoma (RCC) is one of the most common oncological diagnoses worldwide. Accurate staging and restaging imaging continue to be a priority in clinical practice as 20% to 30% of patients present with advanced metastatic disease at diagnosis, and 20% to 30% develop recurrence after surgical resection. We present a case of a 71-year-old man presenting with an isolated pituitary RCC metastasis accurately defined on 18F-prostate-specific membrane antigen-1007 masquerading as a macroadenoma on conventional imaging (CT and MRI). This demonstrates the potential utility of 18F-prostate-specific membrane antigen-1007 in characterizing RCC brain metastasis.

Painless penile periurethral polymicrobial abscess causing urinary retention.

In contemporary urological practice periurethral abscesses are rare. We report the case of a 61-year-old presenting with a painless penile mass and urinary retention. He underwent imaging with ultrasonography, targeted antibiotics and successful source control through open incision and drainage. He has been symptom, recurrence and complication free at 24 months post intervention. Risk factors for abscesses include obstruction, trauma, urethral diverticula and urethral carcinoma. Inadequate detection and treatment may lead to urethral fistulae, strictures and rarely, necrotizing fasciitis. To our knowledge, this is the first report of a periurethral abscess presenting as a painless penile mass causing urinary retention.

Urothelial Carcinoma and Prostate-specific Membrane Antigen: Cellular, Imaging, and Prognostic Implications.

CONTEXT: Staging, restaging, and surveillance of urothelial carcinoma (UC) is challenging due to suboptimal accuracy of standard of care imaging modalities. Prostate-specific membrane antigen (PSMA) imaging may serve to improve characterisation of UC. OBJECTIVE: To appraise available literature regarding cellular, imaging, and prognostic implications of PSMA for UC. EVIDENCE ACQUISITION: A systematic review was performed considering all available literature (including conference abstracts) published from 1990 to 2020 and reported according to Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines following registration in PROSPERO (CRD42020186744). All relevant texts relating to immunohistochemical analysis and PSMA-based imaging in UC were included and collated. Additionally, FOLH1 (gene encoding PSMA) expression according to The Cancer Genome Atlas (TCGA) database was analysed as well as according to consensus and TCGA molecular classification subtypes and subsequently compared with clinical outcomes. EVIDENCE SYNTHESIS: PSMA expression across UC tumour tissue was heterogeneous (0-100%) but appeared to decrease with increased grade and stage. The TCGA analysis demonstrated loss of FOLH1 expression with increasing T stage (p = 0.0180) and N stage (p = 0.0269), and reduced FOLH1 expression was associated with worse disease-free survival. PSMA expression in UC neovasculature was variable but mostly increased (44-100%). Eleven reports of PSMA-based imaging for UC were identified, reporting on 18 patients. PSMA positron emission tomography (PET) imaging was positive in 17 out of 18 patients. The included literature review data were limited by mostly low-quality, retrospective studies. CONCLUSIONS: Tissue PSMA, or FOLH1 expression, may inversely be associated with pathological and survival outcomes in localised UC. PSMA PET imaging may improve detection of metastatic disease and response to systemic therapy due to PSMA expression in neovasculature. Available evidence is limited; thus, larger, prospective studies are required to confirm early results and define populations that benefit most. PATIENT SUMMARY: In this systematic review, we assess the potential role of prostate-specific membrane antigen in urothelial cancer. We found that its utility is in expression of blood vessels surrounding metastasis. We conclude that it may be beneficial in detecting metastasis and response to systemic therapies.

Characterization of tumor thrombus in renal cell carcinoma with prostate specific membrane antigen (PSMA) positron emission tomography (PET)/computed tomography (CT).

INTRODUCTION: Venous tumor thrombus (TT) occurs as part of the natural history of renal cell carcinoma (RCC) local progression in a small minority of cases. MRI is currently the most accurate imaging modality for determining TT extent. PSMA PET/CT may improve RCC staging and IVC TT characterization. The objective of this study was to investigate the role of PSMA PET/CT in defining superior extent of TT in RCC and TT IVC tributary vessel spread, with comparative accuracy vs. MRI, to assess suitability for resection and inform preoperative surgical planning. METHODS: Patients who underwent PSMA PET/CT for assessment of renal malignancy with TT from 2015 to 2020 at 3 tertiary hospitals in Brisbane, Australia, were retrospectively identified. TT extent was classified using Mayo Clinic levels and compared according to imaging modality. RESULTS: Fourteen patients were included, all of which were clear cell RCC. Ten patients also underwent MRI, 6 of which were concordant in extent according to MRI and PSMA PET. Discordant extent occurred in 4 patients, of which 2 patients had non-PSMA avid thrombus (Mayo level 0 and level 3 on MRI). Further discordance was seen in a patient with adrenal vein and lumbar vein TT only seen on MRI and PSMA PET/CT, respectively. Finally, discordant extent was seen in another patient with Mayo level 4 TT without lumbar vein involvement on MRI vs. level 3 on PSMA PET/CT with lumbar vein involvement. CONCLUSIONS: PSMA PET/CT can provide additional information about TT extent in RCC which may not be seen on MRI. Additional information from PSMA PET/CT in this setting may assist surgical planning, in addition to detection of metastatic disease.

The role of dual tracer PSMA and FDG PET/CT in renal cell carcinoma (RCC) compared to conventional imaging: A multi-institutional case series with intra-individual comparison.

PURPOSE: The objective of this study was to perform an intra-individual dual tracer comparison of Fluorodeoxyglucose (FDG) and Prostate Specific Membrane Antigen (PSMA) computed tomography (CT)/Positron Emission Tomography (PET) against standard of care (SOC) imaging for the characterisation, staging and restaging of renal cell carcinoma (RCC). METHODS: A multicentre retrospective cohort study was performed at 3 major tertiary referral institutions in Brisbane, Australia between 2015 and 2020. All patients who underwent both PSMA and FDG PET/CT following SOC imaging for investigation of RCC were identified. Clinical details, imaging characteristics and histopathology were collected prior to univariate statistical analysis. RESULTS: Eleven patients who underwent dual tracer PET/CT were included. Mean age was 65.5 years (SD 8.8). Most patients were male (64%) with clear cell morphology (91%). The indication for dual tracer PET was staging (36%) and restaging after radical/partial nephrectomy (64%). Primary tumour assessment showed mixed avidity patterns (concordant 40%, discordant favouring PSMA 20%, and FDG 40%). Metastatic disease assessment showed concordant avidity in 6 patients (55%), concordant negative in 3 (27%), and discordant uptake favouring PSMA. PET outperformed SOC imaging for assessment of metastatic disease in 5 patients (45%) and equivalent for the remainder. A change in management was noted in three cases (27%). CONCLUSION: Dual tracer FDG and PSMA PET/CT for assessment of primary and metastatic RCC were mostly concordant. PET imaging outperformed conventional imaging and led to a change in management for 1 in 4 patients. Further studies with larger samples sizes are required to validate these findings and identify characteristics to guide patient selection for selective or dual tracer use.