Kinetic modeling of 68Ga-PSMA-11 and validation of simplified methods for quantification in primary prostate cancer patients.

BACKGROUND: The positron emission tomography (PET) ligand 68Ga-Glu-urea-Lys(Ahx)-HBED-CC (68Ga-PSMA-11) targets the prostate-specific membrane antigen (PSMA), upregulated in prostate cancer cells. Although 68Ga-PSMA-11 PET is widely used in research and clinical practice, full kinetic modeling has not yet been reported nor have simplified methods for quantification been validated. The aims of our study were to quantify 68Ga-PSMA-11 uptake in primary prostate cancer patients using compartmental modeling with arterial blood sampling and to validate the use of standardized uptake values (SUV) and image-derived blood for quantification. RESULTS: Fifteen patients with histologically proven primary prostate cancer underwent a 60-min dynamic 68Ga-PSMA-11 PET scan of the pelvis with axial T1 Dixon, T2, and diffusion-weighted magnetic resonance (MR) images acquired simultaneously. Time-activity curves were derived from volumes of interest in lesions, normal prostate, and muscle, and mean SUV calculated. In total, 18 positive lesions were identified on both PET and MR. Arterial blood activity was measured by automatic arterial blood sampling and manual blood samples were collected for plasma-to-blood ratio correction and for metabolite analysis. The analysis showed that 68Ga-PSMA-11 was stable in vivo. Based on the Akaike information criterion, 68Ga-PSMA-11 kinetics were best described by an irreversible two-tissue compartment model. The rate constants K1 and k3 and the net influx rate constants Ki were all significantly higher in lesions compared to normal tissue (p < 0.05). Ki derived using image-derived blood from an MR-guided method showed excellent agreement with Ki derived using arterial blood sampling (intraclass correlation coefficient = 0.99). SUV correlated significantly with Ki with the strongest correlation of scan time-window 30-45 min (rho 0.95, p < 0.001). Both Ki and SUV correlated significantly with serum prostate specific antigen (PSA) level and PSA density. CONCLUSIONS: 68Ga-PSMA-11 kinetics can be described by an irreversible two-tissue compartment model. An MR-guided method for image-derived blood provides a non-invasive alternative to blood sampling for kinetic modeling studies. SUV showed strong correlation with Ki and can be used in routine clinical settings to quantify 68Ga-PSMA-11 uptake.

Nephron-sparing surgery for treatment of reninoma: a rare renin secreting tumor causing secondary hypertension

Main findings A 25-year-old hypertensive female patient was referred to our institution. Initial workup exams demonstrated a 2.8 cm cortical lower pole tumor in the right kidney. She underwent laparoscopic partial nephrectomy without complications. Histopathologic examination revealed a rare juxtaglomerular cell tumor known as reninoma. After surgery, she recovered uneventfully and all medications were withdrawn. Case hypothesis Secondary arterial hypertension is a matter of great interest to urologists and nephrologists. Renovascular hypertension, primary hyperadosteronism and pheocromocytoma are potential diagnosis that must not be forgotten and should be excluded. Although rare, chronic pyelonephritis and renal tumors as rennin-producing tumors, nephroblastoma, hypernephroma, and renal cell carcinoma might also induce hypertension and should be in the diagnostic list of clinicians. Promising future implications Approximately 5% of patients with high blood pressure have specific causes and medical investigation may usually identify such patients. Furthermore, these patients can be successfully treated and cured, most times by minimally invasive techniques. This interesting case might expand knowledge of physicians and aid better diagnostic care in future medical practice. .

Anatrophic nephrotomy as nephron-sparing approach for complete removal of intraparenchymal renal tumors

OBJECTIVE: Partial nephrectomy for small kidney tumors has increased in the last decades, and the approach to non-palpable endophytic tumors became a challenge, with larger chances of positive margins or complications. The aim of this study is to describe an alternative nephron-sparing approach for small endophytic kidney tumors through anatrophic nephrotomy. PATIENTS AND METHODS: A retrospective analysis of patients undergoing partial nephrectomy at our institution was performed and the subjects with endophytic tumors treated with anatrophic nephrotomy were identified. Patient demographics, perioperative outcomes and oncological results were evaluated. RESULTS: Among the partial nephrectomies performed for intraparenchymal tumors between 06/2006 and 06/2010, ten patients were submitted to anatrophic nephrotomy. The mean patient age was 42 yrs, and the mean tumor size was 2.3 cm. Mean warm ischemia time was 22.4 min and the histopathological analysis showed 80% of clear cell carcinomas. At a mean follow-up of 36 months, no significant creatinine changes or local or systemic recurrences were observed. CONCLUSION: The operative technique described is a safe and effective nephron-sparing option for complete removal of endophytic renal tumors.

Robot-assisted radical prostatectomy in Brazil: preliminary results / Resultados iniciais da prostatectomia radical robô-assistida no Brasil

Purpose: To report the initial experience on robot-assisted radical prostatectomy in Brazil. Methods: From March 2008 to March 2009, a hundred patients were treated with robot-assisted radical prostatectomy. Patients demographic data, as well as perioperative results of the procedures, are described in this study. Results: Patients mean age and mean PSA were 58 years and 7.58 ng/ml, respectively. All procedures were performed through transperitoneal approach, with a mean bleeding of 480 mL and surgical time of 298 minutes. A surgical margin affected by cancer was present in 16% of the cases. There were four complications: bleeding requiring transfusion (two cases), rectal perforation corrected on the spot and inadequate functioning of the robot. There was no conversion to another access or obit occurrences in this caseload. Conclusions: Robot-assisted prostatectomy is a reality in Brazil and the results herein presented demonstrate that this procedure can be safely performed. Long-term follow-up is still necessary to assess the oncological and functional outcomes.

Objetivo: Relatar a experiência inicial de prostatectomia radical robô-assistida realizada no Brasil. Métodos: No período de março de 2008 a março de 2009, cem pacientes foram tratados com a prostatectomia radical robô-assistida. Os dados demográficos dos pacientes, assim como os resultados perioperatórios dos procedimentos, são descritos neste estudo. Resultados: A média de idade e PSA dos pacientes foi de 58 anos e 7,58 ng/ml, respectivamente. Todos os procedimentos foram realizados por via transperitoneal, com sangramento médio foi de 480 ml e tempo cirúrgico de 298 minutos. A presença de margem cirúrgica comprometida por câncer ocorreu em 16% dos casos. Ocorreram quatro complicações: sangramento com necessidade de transfusão (dois casos), perfuração retal corrigida no ato e funcionamento inadequado do robô. Não houve conversão para outro acesso ou óbitos nesta casuística. Conclusões: A prostatectomia robótica é uma realidade no Brasil e os resultados apresentados demonstram que este procedimento pode ser realizado com segurança. Seguimento a longo prazo ainda é necessário para avaliar os resultados oncológicos e funcionais.

Efeitos do laser KTP na dissecção laparoscópica do feixe neuro-vascular cavernoso em modelo experimental canino / Effect of KTP laser in the laparoscopic dissection of the cavernous neurovascular bundles

Introdução: A energia elétrica e ultrasônica são utilizadas com freqüência na prostatectomia radical laparoscópica e podem lesar os nervos cavernosos adjacentes através da dissipação térmica. Em contrapartida, a energia laser tem potencial para proporcionar uma dissecção precisa, com boa hemostasia e pequena lesão dos tecidos adjacentes. Este estudo avalia o efeito do laser KTP na dissecção laparoscópica do feixe neuro-vascular cavernoso em modelo experimental canino. Material e Métodos: Um total de 36 cães foi dividido igualmente em três grupos. Realizou-se a dissecção unilateral do feixe neurovascular cavernoso utilizando (1) laser KTP (KTP), (2) bisturi ultrasônico (BU), e (3) tesoura e clipes metálicos (TC), mantendo o lado contralateral intacto. Realizou-se a análise do tempo operatório e sangramento em cada grupo, assim como a análise funcional, através do coeficiente entre a pressão intracavernosa e pressão arterial média (PIC/PAM) durante a estimulação do feixe neurovascular cavernoso. Metade dos animais de cada grupo foi mantida viva por 30 dias e submetidos à nova neuroestimulação. Foram avaliados ainda os efeitos da dissipação térmica através da análise termográfica em fragmentos de peritôneo parietal e a extensão histológica da necrose tecidual na fáscia prostática desde a superfície de corte de cada instrumento. Resultados: O tempo de dissecção do feixe neuro-vascular cavernoso foi similar entre os grupos (KTP vs. BU p=0.21, KTP vs. TC p=0.81, BU vs. TC p=0.22). A dissecção utilizando o BU resultou em um prejuízo significativo na resposta à neuroestimulação quando comparado aos grupos TC e KTP no experimento agudo (BU vs. KTP p<0.001, BU vs. TC p<0.001), e crônico (BU vs. KTP p=0.02, BU vs. TC p=0.02). A análise histológica demonstrou uma área de necrose desde a superfície de corte com a utilização do laser KTP de aproximadamente 500 um, enquanto que com o uso do BU essa área se extendeu em média por 2 mm...

Introduction: Electrical and ultrasonic energy used in nerve-sparing laparoscopic radical prostatectomy can compromise cavernous nerve function. Laser energy may potentially allow fine dissection with good hemostasis and minimal adjacent tissue injury. This study examines the electrophysiological, histological and thermal mapping features of KTP laser dissection on cavernous nerve function in the survival canine model. Materials and Methods: A total of 36 dogs were divided into 3 groups. Laparoscopic unilateral neurovascular bundle (NVB) mobilization was performed using either: (1) KTP laser (n=12), (2) ultrasonic shears (US) (n=12), or (3) athermally with cold scissors (AT) (n=12). The contralateral NVB remained undissected as an internal control. NVB function was assessed acutely in all dogs, and after 1-month survival in 50% of the dogs of each group. Peak intracavernosal pressure response to cavernous nerve stimulation was measured as a percentage of mean arterial pressure (ICP/MAP). Strips of peritoneum were sectioned ex-vivo with the KTP laser and US shears for thermographic mapping. Histological evaluation of prostatic fascia necrosis from the cutting surface was also performed. Results: Comparing KTP and AT groups, the erectile response to nerve stimulation was similar acutely and at 1 month (acute ICP/MAP: KTP 92%, AT 96% p=0.54; chronic ICP/MAP: KTP 95%, AT 98% p=0.71). In contrast, US dissection resulted in a significant decrease in the ICP response compared to the KTP and AT groups (acute ICP/MAP: US 49%, KTP 92%, AT 96%. US vs. KTP p<0.001, US vs. AT p<0.001; chronic ICP/MAP: US 58%, KTP 95%, AT 98%, US vs. KTP p=0.02, US vs. AT p=0.02). Mean NVB dissection times were similar (KTP 27.5min, US 19.9min, AT 26.6min, KTP vs. US p=0.21, KTP vs. AT p=0.81, US vs. AT p=0.22). Histopathology demonstrated an acute zone of laser-induced necrosis of approximately 500 um compared to 2 mm with US dissection...

Laparoscopic treatment of retroperitoneal fibrosis: report of two cases and review of the literature

OBJECTIVES: We present the results of treatment by laparoscopy of two patients with retroperitoneal fibrosis and review the literature since 1992, when the first case of this disease that was treated using laparoscopy was published. We also discuss the contemporary alternatives of clinical treatment with corticosteroids and tamoxifen. CASE REPORT: Two female patients, one with idiopathic retroperitoneal fibrosis, and other with retroperitoneal fibrosis associated with Riedel's thyroiditis, were treated using laparoscopic surgery. Both cases had bilateral pelvic ureteral obstruction and were treated using the same technique: transperitoneal laparoscopy, medial mobilization of both colons, liberation of both ureters from the fibrosis, and intraperitonealisation of the ureters. Double-J catheters were inserted before the operations and removed 3 weeks after the procedures. The first patient underwent intraperitonealisation of both ureters in a single procedure. The other had 2 different surgical procedures because of technical difficulties during the first operation. Both patients were followed for more than 1 year and recovered completely from the renal insufficiency. One of them still has occasional vague lumbar pain. There were no abnormalities in the intravenous pyelography in either case. CONCLUSIONS: Surgical correction of retroperitoneal fibrosis, when indicated, should be attempted using laparoscopy. If possible, bilateral ureterolysis and intraperitonealisation of both ureters should be performed in the same operation