Publications by authors named "Jeffrey Gahan"

51 Publications

Rethinking Autonomous Surgery: Focusing on Enhancement over Autonomy.

Eur Urol Focus 2021 Jul 7. Epub 2021 Jul 7.

Department of Mechanical Engineering, University of Texas at Austin, Austin, TX, USA. Electronic address:

Context: As robot-assisted surgery is increasingly used in surgical care, the engineering research effort towards surgical automation has also increased significantly. Automation promises to enhance surgical outcomes, offload mundane or repetitive tasks, and improve workflow. However, we must ask an important question: should autonomous surgery be our long-term goal?

Objective: To provide an overview of the engineering requirements for automating control systems, summarize technical challenges in automated robotic surgery, and review sensing and modeling techniques to capture real-time human behaviors for integration into the robotic control loop for enhanced shared or collaborative control.

Evidence Acquisition: We performed a nonsystematic search of the English language literature up to March 25, 2021. We included original studies related to automation in robot-assisted laparoscopic surgery and human-centered sensing and modeling.

Evidence Synthesis: We identified four comprehensive review papers that present techniques for automating portions of surgical tasks. Sixteen studies relate to human-centered sensing technologies and 23 to computer vision and/or advanced artificial intelligence or machine learning methods for skill assessment. Twenty-two studies evaluate or review the role of haptic or adaptive guidance during some learning task, with only a few applied to robotic surgery. Finally, only three studies discuss the role of some form of training in patient outcomes and none evaluated the effects of full or semi-autonomy on patient outcomes.

Conclusions: Rather than focusing on autonomy, which eliminates the surgeon from the loop, research centered on more fully understanding the surgeon's behaviors, goals, and limitations could facilitate a superior class of collaborative surgical robots that could be more effective and intelligent than automation alone.

Patient Summary: We reviewed the literature for studies on automation in surgical robotics and on modeling of human behavior in human-machine interaction. The main application is to enhance the ability of surgical robotic systems to collaborate more effectively and intelligently with human surgeon operators.
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http://dx.doi.org/10.1016/j.euf.2021.06.009DOI Listing
July 2021

Single-cell analysis of mouse and human prostate reveals novel fibroblasts with specialized distribution and microenvironment interactions.

J Pathol 2021 Jun 26. Epub 2021 Jun 26.

Department of Urology, UT Southwestern Medical Center, Dallas, TX, USA.

Stromal-epithelial interactions are critical to the morphogenesis, differentiation, and homeostasis of the prostate, but the molecular identity and anatomy of discrete stromal cell types is poorly understood. Using single-cell RNA sequencing, we identified and validated the in situ localization of three smooth muscle subtypes (prostate smooth muscle, pericytes, and vascular smooth muscle) and two novel fibroblast subtypes in human prostate. Peri-epithelial fibroblasts (APOD+) wrap around epithelial structures, whereas interstitial fibroblasts (C7+) are interspersed in extracellular matrix. In contrast, the mouse displayed three fibroblast subtypes with distinct proximal-distal and lobe-specific distribution patterns. Statistical analysis of mouse and human fibroblasts showed transcriptional correlation between mouse prostate (C3+) and urethral (Lgr5+) fibroblasts and the human interstitial fibroblast subtype. Both urethral fibroblasts (Lgr5+) and ductal fibroblasts (Wnt2+) in the mouse contribute to a proximal Wnt/Tgfb signaling niche that is absent in human prostate. Instead, human peri-epithelial fibroblasts express secreted WNT inhibitors SFRPs and DKK1, which could serve as a buffer against stromal WNT ligands by creating a localized signaling niche around individual prostate glands. We also identified proximal-distal fibroblast density differences in human prostate that could amplify stromal signaling around proximal prostate ducts. In human benign prostatic hyperplasia, fibroblast subtypes upregulate critical immunoregulatory pathways and show distinct distributions in stromal and glandular phenotypes. A detailed taxonomy of leukocytes in benign prostatic hyperplasia reveals an influx of myeloid dendritic cells, T cells and B cells, resembling a mucosal inflammatory disorder. A receptor-ligand interaction analysis of all cell types revealed a central role for fibroblasts in growth factor, morphogen, and chemokine signaling to endothelia, epithelia, and leukocytes. These data are foundational to the development of new therapeutic targets in benign prostatic hyperplasia. © 2021 The Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
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http://dx.doi.org/10.1002/path.5751DOI Listing
June 2021

Use of Pre-operative Pharmacologic Venous Thromboembolism Prophylaxis for Robotic Partial Nephrectomy.

Urology 2021 Apr 28. Epub 2021 Apr 28.

UT Southwestern Medical Center, Department of Urology, Dallas, TX.

Objective: To determine whether a single dose of preoperative enoxaparin for venous thromboembolism (VTE) prophylaxis impacts rates of thrombotic and bleeding events after robotic partial nephrectomy (RPNx).

Methods: A retrospective cohort study of RPNx patients from 2009 to 2020 was performed. Clinical characteristics and perioperative outcomes were compared between patients receiving a single dose of preoperative enoxaparin and those who did not. The primary outcome was 30-day hemorrhagic complications (transfusion ≥2 units, embolization, or reoperation for bleeding). Secondary outcomes were 30-day VTE events. Multivariable logistic regression was performed to control for significant differences between groups and to identify predictors of hemorrhagic complications among patients.

Results: Among 945 RPNx procedures, 794 (84%) received preoperative enoxaparin (PPx) and 151 (16%) did not (NPPx). The PPx cohort was older (P = .004), had lower BMI (P = .03), lower ASA class (P = .049), and fewer smokers (P = .03). Warm ischemia time was longer for PPx patients (P < .001). 4.9% and 2.6% of the PPx and NPPx cohorts, respectively, developed postoperative hemorrhagic complications (P = .29). After adjustment for potential covariates, pharmacologic prophylaxis was not associated with 30-day hemorrhagic complications (P = .39). On multivariable regression, longer warm ischemia time (OR 1.05, 95% CI 1.01-1.10, P = .02) and greater tumor size (OR 1.27, 95% CI 1.03-1.56, P = .02) were predictors of hemorrhagic complications. 30-day readmissions, VTE events, and mortality were similar between groups (all P> 0.05).

Conclusion: Similar rates of thrombotic and bleeding events occurred between patients receiving pharmacologic prophylaxis and those who did not. Single dose of preoperative enoxaparin did not significantly alter perioperative outcomes after RPNx.
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http://dx.doi.org/10.1016/j.urology.2021.03.043DOI Listing
April 2021

Single-port robotic-assisted simple prostatectomy is associated with decreased post-operative narcotic use in a propensity score matched analysis.

J Robot Surg 2021 Apr 10. Epub 2021 Apr 10.

Department of Urology, University of Texas Southwestern, 2001 Inwood Dr., WCB3, Suite 4.878, Dallas, TX, 75390 MC 9110, USA.

Robotic-assisted simple prostatectomy (RASP) has proven to be an effective minimally invasive option for benign prostatic enlargement (BPE) in recent years. Single-site surgery is theorized to reduce post-operative pain beyond traditional minimally invasive approaches. We sought to assess whether use of a single-port robotic platform decreases post-operative opioid use in patients undergoing robotic-assisted simple prostatectomy (RASP). A retrospective review was performed of all patients undergoing RASP our institution from November 2017 to July 2019. Demographic, intraoperative, and post-operative data, including morphine equivalent (ME) use, were collected. Patients were stratified by robotic platform utilized. Propensity score matching using nearest neighbor method was performed using prostate volume, Charlson comorbidity index (CCI), and post-op ketorolac use in 4:1 fashion. Chi-squared analysis and Kruskal-Wallis analyses were utilized. Two-hundred-and-seven men underwent RASP. After matching, 80 patients (64 multi-port, 16 single-port) were included in the analysis. Groups were comparable for age, body mass index, CCI, prostate volume, prior opioid use, and use of scheduled ketorolac post op. The single-port approach was associated with a reduction in MEs once admitted to the floor (5 vs. 11 mg, p = 0.025) and an increase in the proportion of patients who did not require any narcotics post-operatively (44 vs. 19%, p = 0.036). In a propensity matched cohort of patients undergoing RASP at a single institution, use of the single-port robotic system conferred a significant decrease in post-operative narcotic use by approximately 50%.
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http://dx.doi.org/10.1007/s11701-021-01236-1DOI Listing
April 2021

Neoadjuvant SABR for Renal Cell Carcinoma Inferior Vena Cava Tumor Thrombus-Safety Lead-in Results of a Phase 2 Trial.

Int J Radiat Oncol Biol Phys 2021 Jul 5;110(4):1135-1142. Epub 2021 Feb 5.

Kidney Cancer Program, Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center, Dallas, Texas; Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas. Electronic address:

Purpose: To evaluate the feasibility, safety, oncologic outcomes, and immune effect of neoadjuvant stereotactic radiation (Neo-SAbR) followed by radical nephrectomy and thrombectomy (RN-IVCT).

Methods And Materials: These are results from the safety lead-in portion of a single-arm phase 1 and 2 trial. Patients with kidney cancer (renal cell carcinoma [RCC]) and inferior vena cava (IVC) tumor thrombus (TT) underwent Neo-SAbR (40 Gy in 5 fractions) to the IVC-TT followed by open RN-IVCT. Absence of grade 4 to 5 adverse events (AEs) within 90 days of RN-IVCT was the primary endpoint. Exploratory studies included pathologic and immunologic alterations attributable to SAbR.

Results: Six patients were included in the final analysis. No grade 4 to 5 AEs were observed. A total of 81 AEs were reported within 90 days of surgery: 73% (59/81) were grade 1, 23% (19/81) were grade 2, and 4% (3/81) were grade 3. After a median follow-up of 24 months, all patients are alive. One patient developed de novo metastatic disease. Of 3 patients with metastasis at diagnosis, 1 had a complete and another had a partial abscopal response without the concurrent use of systemic therapy. Neo-SABR led to decreased Ki-67 and increased PD-L1 expression in the IVC-TT. Inflammatory cytokines and autoantibody titers reflecting better host immune status were observed in patients with nonprogressive disease.

Conclusions: Neo-SAbR followed by RN-IVCT for RCC IVC-TT is feasible and safe. Favorable host immune environment correlated with abscopal response to SABR and RCC relapse-free survival, though direct causal relation to SABR has yet to be established.
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http://dx.doi.org/10.1016/j.ijrobp.2021.01.054DOI Listing
July 2021

Experienced bedside-assistants improve operative outcomes for surgeons early in their learning curve for robot assisted laparoscopic radical prostatectomy.

J Robot Surg 2021 Aug 1;15(4):619-626. Epub 2020 Oct 1.

Department of Urology, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd. J8. 112C, Dallas, TX, 75390, USA.

Robot-assisted laparoscopic radical prostatectomy (RALP) relies heavily on the bedside assistant (BA). Currently, the relationship between BA experience and surgical outcomes in robotic surgery is not clear. We examined whether bedside assistant experience can significantly affect positive margin rate and peri-operative outcomes for RALP for surgeons within their learning curve. A retrospective cohort study of a single surgeon's peri-operative outcomes during RALP was examined and compared with and without an experienced bedside assistant. Patient demographic data and peri-operative data, margin rate, and length of stay (LOS), were collected and analyzed. Univariate and multivariable analyses were performed to determine if expert BA was a predictor of post-operative outcomes. In total, 170 consecutive cases over three years were analyzed. 111 (65%) were performed without an expert BA. The two groups were not significantly different with regards patient demographics (p > 0.05). On univariate analysis, having an expert BA was associated with a significantly lower LOS (31 h ± 21 vs. 42 h ± 26, p = 0.004), EBL (296 ml ± 180 vs. 441 ml ± 305, p < 0.0001) and positive margin rate (20% vs. 37%, p = 0.03). Other surgical outcomes were comparable between groups. On multivariable analysis, expert BA remained a predictor of, EBL (B stat = - 146, 95% CI - 240 to - 52, p = 0.003) and positive margin rate (OR 0.4, 95% CI 0.2-0.96, p = 0.04). Our results demonstrate that the use of an expert BA may result in improved patient outcomes early in the learning curve of RALP, most notably, positive margin rate and estimated blood loss.
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http://dx.doi.org/10.1007/s11701-020-01146-8DOI Listing
August 2021

Feasibility and Safety of Robotic Excision of Ipsilateral Retroperitoneal Recurrence After Nephrectomy for Renal Cell Carcinoma.

Urology 2020 Nov 21;145:159-165. Epub 2020 Aug 21.

Department of Urology, University of Texas Southwestern Medical Center, Dallas, TX, USA; Institute for Urology and Reproductive Health, Sechenov University, Moscow, Russia. Electronic address:

Objective: To determine feasibility and safety of robotic excision of local ipsilateral recurrences after nephrectomy for renal cell carcinoma (RCC). Surgical resection is an option for treatment of low burden locally recurrent RCC, potentially delaying the use of systemic therapy. This has historically been performed by open technique, which can impart significant morbidity. We present our experience with robotic excision.

Methods: We reviewed our institutional experience of patients with surgically excised RCC who underwent robotic excision of ipsilateral retroperitoneal recurrence in 2015-2018. Demographics and clinicopathological variables, including operative and postoperative outcomes, were examined.

Results: Twelve robotic excisions of ipsilateral local recurrences were performed in our hospital in 2015-2018. Mean age was 65.48 years (± standard deviation, SD: 9.51), 10 patients were male, and mean BMI 34.75 kg/m (± 6.71). Nine patients recurred after radical nephrectomy, and 3 after partial nephrectomy. Mean size of recurrence was 2.97 cm (±1.69). Mean anesthesia time, EBL, and LOS were 213 minutes (± 38.92), 152 mL (± 130.75), and 43 hours (± 12.64), respectively. All surgical margins were negative. No surgical complications were reported. Median follow-up was 19.0 months [interquartile range, IQR 12.7-30.0]. Five patients out of 12 recurred following robotic excision, these were treated with either systemic therapy, radiation, or palliative surgeries. Mean time for subsequent recurrence was 26.5 months.

Conclusion: In this small case series, robotic excision of ipsilateral RCC retroperitoneal recurrence appears safe, technically feasible, and oncologically sound in expert hands and carefully selected patients.
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http://dx.doi.org/10.1016/j.urology.2020.07.060DOI Listing
November 2020

Urethral luminal epithelia are castration-insensitive cells of the proximal prostate.

Prostate 2020 08 4;80(11):872-884. Epub 2020 Jun 4.

Department of Urology, UT Southwestern Medical Center, Dallas, Texas.

Background: Castration-insensitive epithelial progenitors capable of regenerating the prostate have been proposed to be concentrated in the proximal region based on facultative assays. Functional characterization of prostate epithelial populations isolated with individual cell surface markers has failed to provide a consensus on the anatomical and transcriptional identity of proximal prostate progenitors.

Methods: Here, we use single-cell RNA sequencing to obtain a complete transcriptomic profile of all epithelial cells in the mouse prostate and urethra to objectively identify cellular subtypes. Pan-transcriptomic comparison to human prostate cell types identified a mouse equivalent of human urethral luminal cells, which highly expressed putative prostate progenitor markers. Validation of the urethral luminal cell cluster was performed using immunostaining and flow cytometry.

Results: Our data reveal that previously identified facultative progenitors marked by Trop2, Sca-1, KRT4, and PSCA are actually luminal epithelial cells of the urethra that extend into the proximal region of the prostate, and are resistant to castration-induced androgen deprivation. Mouse urethral luminal cells were identified to be the equivalent of previously identified human club and hillock cells that similarly extend into proximal prostate ducts. Benign prostatic hyperplasia (BPH) has long been considered an "embryonic reawakening," but the cellular origin of the hyperplastic growth concentrated in the periurethral region is unclear. We demonstrate an increase in urethral luminal cells within glandular nodules from BPH patients. Urethral luminal cells are further increased in patients treated with a 5-α reductase inhibitor.

Conclusions: Our data demonstrate that cells of the proximal prostate that express putative progenitor markers, and are enriched by castration in the proximal prostate, are urethral luminal cells and that these cells may play an important role in the etiology of human BPH.
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http://dx.doi.org/10.1002/pros.24020DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7339731PMC
August 2020

A complex dual-modality kidney phantom for renal biopsy studies.

Proc SPIE Int Soc Opt Eng 2020 Feb 16;11319. Epub 2020 Mar 16.

Department of Bioengineering, The Univ. of Texas at Dallas, TX.

We developed a reliable and repeatable process to create hyper-realistic, kidney phantoms with tunable image visibility under ultrasound (US) and CT imaging modalities. A methodology was defined to create phantoms that could be produced for renal biopsy evaluation. The final complex kidney phantom was devised containing critical structures of a kidney: kidney cortex, medulla, and ureter. Simultaneously, some lesions were integrated into the phantom to mimic the presence of tumors during biopsy. The phantoms were created and scanned by ultrasound and CT scanners to verify the visibility of the complex internal structures and to observe the interactions between material properties. The result was a successful advancement in knowledge of materials with ideal acoustic and impedance properties to replicate human organs for the field of image-guided interventions.
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http://dx.doi.org/10.1117/12.2549892DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7261611PMC
February 2020

Renal biopsy under augmented reality guidance.

Proc SPIE Int Soc Opt Eng 2020 Feb 16;11315. Epub 2020 Mar 16.

Department of Bioengineering, The Univ. of Texas at Dallas, TX.

Kidney biopsies are currently performed using preoperative imaging to identify the lesion of interest and intraoperative imaging used to guide the biopsy needle to the tissue of interest. Often, these are not the same modalities forcing the physician to perform a mental cross-modality fusion of the preoperative and intraoperative scans. This limits the accuracy and reproducibility of the biopsy procedure. In this study, we developed an augmented reality system to display holographic representations of lesions superimposed on a phantom. This system allows the integration of preoperative CT scans with intraoperative ultrasound scans to better determine the lesion's real-time location. An automated deformable registration algorithm was used to increase the accuracy of the holographic lesion locations, and a magnetic tracking system was developed to provide guidance for the biopsy procedure. Our method achieved a targeting accuracy of 2.9 ± 1.5 mm in a renal phantom study.
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http://dx.doi.org/10.1117/12.2550593DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7261605PMC
February 2020

Extracorporeal ureter handling during laparoscopic pyeloplasty: tips and tricks for beginners.

Cent European J Urol 2019 6;72(4):413-417. Epub 2019 Dec 6.

Institute for Urology and Reproductive Health, Sechenov University, Moscow, Russia.

Introduction: Laparoscopic preparation of the ureter is a challenging part of upper urinary tract reconstruction, due to limited depth perception provided by the camera and lack of wristed motion of most laparoscopic instruments needed for adequate spatulation and scar tissue removal. One solution has been to perform the more difficult portions of the surgery in an extracorporeal manner. A hybrid intracorporeal-extracorporeal approach to upper tract ureteral reconstruction facilitates ureteral preparation at the stage of mastering the technique.

Material And Methods: This retrospective study included 100 patients with primary ureteropelvic junction obstruction, who underwent laparoscopic pyeloplasty from 2014 to 2017. The patients were stratified into 2 groups: those who underwent conventional laparoscopic surgery and those who were managed with the hybrid approach. For the hybrid approach, externalizing the ureter to skin level required additional mobilization of the upper urinary tract.

Results: A total of 47 patients underwent conventional laparoscopic pyeloplasty and 53 - hybrid surgery. The maximum body mass index was 32. The hybrid approach was 8.5 minutes shorter compared to the conventional approach (p <0.001). No complications higher than Clavien-Dindo IIIb (n = 2) were observed (in both groups). Complete success (the resolution of pain and/or hydronephrosis) was observed in 92.5% in the hybrid group and in 95.7% in the conventional treatment group.

Conclusions: Hybrid pyeloplasty may be considered safe and effective. It has the advantage of making the surgery less challenging and time-consuming while offering improved precision. The advantages of the technique are particularly apparent during training. This technique can be recommended in the learning process of the surgeon.
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http://dx.doi.org/10.5173/ceju.2019.0022DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6979559PMC
December 2019

Initial experience with extraperitoneal robotic-assisted simple prostatectomy using the da Vinci SP surgical system.

J Robot Surg 2020 Aug 27;14(4):601-607. Epub 2019 Sep 27.

Department of Urology, University of Texas Southwestern, 2001 Inwood Dr., WCB3, Suite 4.878, MC 9110, Dallas, TX, 75390, USA.

Robotic-assisted simple prostatectomy (RASP) has emerged as a safe and effective treatment option for symptomatic patients with lower urinary tract symptoms related to significant benign prostatic enlargement (BPE) above 80 g. The recent release of the da Vinci SP robotic system (Intuitive, Sunnyvale, CA, USA) continues to advance the minimally invasive nature of robotic surgical technology. We now report our institution's initial experience performing RASP using the da Vinci SP robotic system. An IRB-approved, retrospective chart review was performed of all patients undergoing robotic-assisted simple prostatectomy using the da Vinci SP surgical system in the treatment of benign prostatic enlargement by a single surgeon from March to June 2019. Pre-operative, intraoperative, and post-operative data were collected for descriptive analysis. A total of 10 men, mean age of 69 ± 4 years, with mean prostate volume of 104 ± 11 g underwent surgery. The robotic cannula and a single assistant port were utilized in all cases. No cases required conversion to a multi-port robotic platform or open approach, nor required the placement of additional assistant ports. No intraoperative or immediate post-operative complications were noted. Mean estimated blood loss was 141 ± 98 mL and operative time was 172 ± 19 min. Mean catheter time was 1.9 ± 1.8 days. One patient reported transient de novo stress urinary incontinence. Single-port RASP is a safe and effective intervention for BPE. The smaller surgical footprint from the device appears to make earlier catheter removal possible. Comparative evaluation with multi-port RASP and other modalities is warranted.
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http://dx.doi.org/10.1007/s11701-019-01029-7DOI Listing
August 2020

Pathologic response and surgical outcomes in patients undergoing nephrectomy following receipt of immune checkpoint inhibitors for renal cell carcinoma.

Urol Oncol 2019 12 12;37(12):924-931. Epub 2019 Sep 12.

Department of Urology, University of Texas Southwestern Medical Center, Dallas, TX. Electronic address:

Objective: To evaluate the pathologic response, safety, and feasibility of nephrectomy following receipt of immune checkpoint inhibition (ICI) for renal cell carcinoma (RCC).

Methods: Patients who underwent nephrectomy for RCC after exposure to nivolumab monotherapy or combination ipilimumab/nivolumab were reviewed. Primary surgical outcomes included operative time (OT), estimated blood loss (EBL), length of stay (LOS), readmission rates, and complication rates. Pathologic response in the primary and metastatic sites constituted secondary outcomes.

Results: Eleven nephrectomies (10 radical, 1 partial) were performed in 10 patients after ICI with median postoperative follow-up 180 days. Six patients received 1 to 4 cycles of ipilimumab/nivolumab, while 5 received 2 to 12 infusions of nivolumab preoperatively. Five surgeries were performed laparoscopically, and 4 patients underwent concomitant thrombectomy. One patient exhibited complete response (pT0) to ICI, and 3/4 patients who underwent metastasectomy for hepatic, pulmonary, or adrenal lesions exhibited no detectable malignancy in any of the metastases resected. No patients experienced any major intraoperative complications, and all surgical margins were negative. Median OT, EBL, and LOS were 180 minutes, 100 ml, and 4 days, respectively. Four patients experienced a complication, including 3 that were addressed with interventional radiology procedures. One patient died of progressive disease >3 months after surgery, and 1 patient succumbed to pulmonary embolism complicated by sepsis. No complications or readmissions were noted in 6 patients.

Conclusion: Nephrectomy following ICI for RCC is safe and technically feasible with favorable surgical outcomes and pathologic response. Timing of the nephrectomy relative to checkpoint dosing did not seem to impact outcome. Biopsies of lesions responding radiographically to ICI may warrant attention prior to surgical excision.
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http://dx.doi.org/10.1016/j.urolonc.2019.08.012DOI Listing
December 2019

Design and Validation of a Low-Cost, High-Fidelity Model for Urethrovesical Anastomosis in Radical Prostatectomy.

J Endourol 2019 04 13;33(4):331-336. Epub 2019 Mar 13.

1 Department of Urology, University of Texas Southwestern, Dallas, Texas.

Objective: We sought to develop and validate a low-cost, high-fidelity robotic surgical model for the urethrovesical anastomosis component of the robot-assisted laparoscopic radical prostatectomy.

Materials And Methods: A novel simulation model was constructed using a 3D-printed model of the male bony pelvis from CT scan data and silicone molds to recreate the soft tissue aspects. Using a da Vinci Si surgical robot, urology faculty and trainees performed simulated urethrovesical anastomosis. Each participant was given 12 minutes to complete the simulation. A survey established face validity, content validity, and acceptability. Simulation runs were evaluated by three blinded reviewers. The anastomosis was graded by two reviewers for suture placement accuracy and anastomosis quality. These factors were compared with robotic experience to establish construct validity.

Results: Twenty participants took part in the initial validation of this model. Groups were defined as experts (surgical faculty), intermediate (fellows and chief residents), and novices (junior residents). Likert scores (1-5 scale, top score 5) examining face validity, content validity, and acceptability were 3.49 ± 0.43, 4.15 ± 0.23, and 4.02 ± 0.19, respectively. Construct validity was excellent based on the model's ability to stratify groups. All evaluated metrics were statistically different between the three levels of training. Total material cost was $2.50 per model.

Conclusions: We developed a novel low-cost robotic simulation of the urethrovesical anastomosis for robot-assisted radical prostatectomy. The model discerns robotic skill level across all levels of training and was found favorable by participants showing excellent face, content, and construct validities.
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http://dx.doi.org/10.1089/end.2018.0871DOI Listing
April 2019

A Cellular Anatomy of the Normal Adult Human Prostate and Prostatic Urethra.

Cell Rep 2018 12;25(12):3530-3542.e5

Department of Urology, UT Southwestern Medical Center, Dallas, TX 75390, USA. Electronic address:

A comprehensive cellular anatomy of normal human prostate is essential for solving the cellular origins of benign prostatic hyperplasia and prostate cancer. The tools used to analyze the contribution of individual cell types are not robust. We provide a cellular atlas of the young adult human prostate and prostatic urethra using an iterative process of single-cell RNA sequencing (scRNA-seq) and flow cytometry on ∼98,000 cells taken from different anatomical regions. Immunohistochemistry with newly derived cell type-specific markers revealed the distribution of each epithelial and stromal cell type on whole mounts, revising our understanding of zonal anatomy. Based on discovered cell surface markers, flow cytometry antibody panels were designed to improve the purification of each cell type, with each gate confirmed by scRNA-seq. The molecular classification, anatomical distribution, and purification tools for each cell type in the human prostate create a powerful resource for experimental design in human prostate disease.
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http://dx.doi.org/10.1016/j.celrep.2018.11.086DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6411034PMC
December 2018

Development and Evaluation of a Novel Endoscopic Sack to Facilitate Tissue Prostate Adenoma Morcellation.

J Endourol 2018 12;32(12):1136-1141

1 Department of Urology, University of Texas Southwestern , Dallas, Texas.

Introduction: Morcellation of the adenoma after laser enucleation of the prostate (LEP) is both time-consuming and prone to complications. We have designed a novel polyethylene sack (ProSac) to improve the morcellation process following LEP. Both silicone and cadaver models were utilized to evaluate the safety and efficacy of ProSac.

Methods: The inanimate model used tissue-mimicking silicone to accurately approximate bladder volume and compliance. The second model was developed using a fresh cadaver. Heat-fixed chicken breast was used to mimic enucleated prostatic adenoma. Morcellation of the simulated adenoma tissue was tested in both models with and without the ProSac. Morcellated tissue was removed from the filter, desiccated, and weighed after each run to establish morcellation efficiency. Visual inspection was used to evaluate for mucosal injury or bladder perforation. A hydromanometer was placed in the cadaveric bladder to measure bladder pressure.

Results: The device was able to capture up to 30 g of tissue with good closure while maintaining good distention and visualization during morcellation. In the silicone model, morcellation efficiency with the device was 4.6 g/minute, while efficiency without the device was 2.6 g/minute (p = 0.03). In the cadaveric model, mean entrapment time was 22 ± 11 seconds. Morcellation efficiency with the device was 2.1 g/minute when excluding entrapment time and 1.9 g/minute including entrapment time. Without the ProSac, morcellation efficiency was 1.2 g/minute (p = 0.05). In both models, multiple mucosal injuries occurred without the device, while none occurred with the device. Bladder pressure was similar between study arms.

Conclusions: The ProSac is a novel device that can provide additional safety during adenoma morcellation. It may also achieve clinically and statistically significant improvement in morcellation efficiency without increasing bladder pressure.
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http://dx.doi.org/10.1089/end.2018.0618DOI Listing
December 2018

Surgical Outcomes of Three vs Four Arm Robotic Partial Nephrectomy: Is the Fourth Arm Necessary?

Urology 2019 01 21;123:140-145. Epub 2018 Sep 21.

Department of Urology, University of Texas Southwestern, Dallas, TX. Electronic address:

Objective: To compare the cost, efficacy, and safety of 3-arm versus 4-arm technique in robotic partial nephrectomy (RPN). Surgeons may either elect to utilize three vs four robotic instruments depending on preference. The purpose of this study is to compare the outcomes between the two techniques.

Methods: RPNs from June 2016 to August 2017 were retrospectively reviewed. Tumor features, surgical parameters, and operative outcomes were evaluated. The number of arms used was determined. Statistical analysis was performed with the Student's t test, chi-squared, and Mann-Whitney test.

Results: A total of 61 consecutive 3-arm RPNs and 59 consecutive 4-arm RPNs were evaluated. Mean tumor diameter and median nephrometry score were 3.4 cm (± 1.1 SD) and 7 (6-8 IQR) for the 3-arm group and 3.3 cm (±1.2 SD) and 6 (5-8 IQR) for the 4-arm group, respectively (size: p = 0.7, nephrometry: p = 0.07). Hospital length of stay, operative time, estimated blood loss, complication rate, blood transfusion rate, and readmission rate all demonstrated no statistically significant difference between 3-arm and 4-arm groups (p >0.05). Mean ischemia time was shorter by 5.1 minutes in the 4-arm group (p = 0.02). Rate of margin positivity was higher in the 4-arm group (0% vs 10%, p = 0.03).

Conclusion: RPN can be safely and effectively completed with 3-robotic arms. While there was increased ischemia time, the difference was small and likely not of clinical significance. The routine addition of the fourth robotic arm in RPN is not necessary.
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http://dx.doi.org/10.1016/j.urology.2018.06.068DOI Listing
January 2019

Determining the Learning Curve for Robot-Assisted Simple Prostatectomy in Surgeons Familiar with Robotic Surgery.

J Endourol 2018 09;32(9):865-870

Department of Urology, University of Texas Southwestern , Dallas, Texas.

Purpose: Robot-assisted simple prostatectomy (RASP) has excellent outcomes when treating large volume prostates and incorporates the already familiar skills to most robotic surgeons. Our objective was to determine the learning curve for RASP.

Materials And Methods: A retrospective review of RASP on 120 consecutive cases performed by two experienced robotic surgeons from 2014 to 2017 was conducted. We defined "learning curve" as the point at which operative parameters transition from logarithmic to linear improvement. Scatter plots of operative outcomes were constructed and logarithmic and linear best-fit line were estimated to determine the point of transition from logarithmic to linear improvement.

Results: Surgeon 1 operated on 76 cases and surgeon 2 on 44 cases. The median age of the 120 patients who underwent RASP was 70.0 years (interquartile range [IQR] 65.0-74.0 years) and median prostate mass was 121.5 g (IQR = 102.0-149.3). Overall, high-grade complication rate was 7.5%; median hematocrit change was 5.4% (IQR = 3.2-7.7) and tissue yield was 61.2 g (IQR = 49.7-76.9). Tissue yield demonstrated logarithmic improvement over the first 12 cases and then transitioned to a linear patter for one surgeon. Operative time in the last 10 cases was statistically different from the first 10 cases (p < 0.01). Drop in hematocrit (ΔHct) for surgeon 2 demonstrated logarithmic improvement for the first 10 cases and then transitioned to a linear pattern.

Conclusion: The learning curve for RASP varied depending on the variable examined. Blood loss (ΔHct) and tissue yield showed the greatest improvement over time, but neither showed significant improvement beyond 12 cases. We estimated the learning curve for RASP to be ∼10 to 12 cases for experienced robotic surgeons.
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http://dx.doi.org/10.1089/end.2018.0377DOI Listing
September 2018

A Randomized Trial Comparing The Learning Curve of 3 Endoscopic Enucleation Techniques (HoLEP, ThuFLEP, and MEP) for BPH Using Mentoring Approach-Initial Results.

Urology 2018 11 24;121:51-57. Epub 2018 Jul 24.

Sechenov University, Research Institute for Uronephrology and Reproductive Health, Russian Federation.

Objective: To assess the differences in the learning curve associated with different techniques of endoscopic enucleation of the prostate.

Materials And Methods: Ninety patients were randomly assigned into 3 groups (30 patients in each): HoLEP, ThuFLEP or MEP. Inclusion criteria for the study included prostate volume <80 cc, IPSS > 20, or Qmax < 10. The EEPs were performed by 3 surgeons experienced in transurethral resection of the prostate. Assignment of surgeons to surgical technique was also randomized. None of the surgeons had prior experience in EEP.

Results: ThuFLEP was slightly superior (with no significant difference [P > .05]) to HoLEP and MEP in terms of overall enucleation rate-1.0 g/min vs 0.8 g/min and 0.7 g/min, respectively. We observed similar enucleation rates at the initial stages of training (first 20 surgeries) with insignificant increase in ThuFLEP efficiency. At next 10 surgeries ThuFLEP and HoLEP efficiency were higher than of MEP (P < .001) without significant difference between techniques of laser EEP (P = .07).

Conclusion: Endoscopic enucleation of the prostate can be adopted safely and effectively within 30 surgeries if the technique is learned with a mentoring approach. EEP is shown to be safe and effective even in the initial stages of learning. Laser EEP (HoLEP, ThuFLEP) appears to lend itself to quicker adaptation compared MEP.
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http://dx.doi.org/10.1016/j.urology.2018.06.045DOI Listing
November 2018

Comparison of Robot-Assisted Versus Open Simple Prostatectomy for Benign Prostatic Hyperplasia.

Curr Urol Rep 2018 Jul 12;19(9):71. Epub 2018 Jul 12.

Department of Urology, University of Massachusetts, 119 Belmont St, Worcester, MA, 01605, USA.

Purpose Of Review: Recent advancements in minimally invasive approaches for prostate surgery have provided numerous options for surgical management of benign prostatic hyperplasia (BPH). In the setting of a large prostate, an open simple prostatectomy was previously considered the gold standard surgical treatment. However, the recently updated American Urological Association (AUA) guidelines on surgical management of BPH now consider both open and minimally invasive approaches to simple prostatectomy viable alternatives for treating large glands, depending on expertise with the techniques. The purpose of our review is to discuss the minimally invasive robot-assisted approach and compare it to the classic open approach to simple prostatectomy.

Recent Findings: Despite longer operative times, the robotic approach is associated with shorter hospital stay and lower morbidity profile. The morbidity of an open approach remains significant. Blood transfusions are 3-4 times as likely compared to a robotic approach and major complications are twice as likely. Consistent with previous literature, our review shows functional outcome improvements like flow rate and symptom score to be comparable between the robotic and open approach. The amount of adenoma resected and PSA decline is also similar among robotic and open cases. Robot-assisted simple prostatectomy is a safe and effective procedure for BPH secondary to a large prostate gland. Appropriately, it is no longer deemed "investigational" by the latest AUA guidelines on BPH and recommended as an alternative to the open approach.
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http://dx.doi.org/10.1007/s11934-018-0820-1DOI Listing
July 2018

Re: Time to consider integration of a formal robotic-assisted surgical training program.

J Robot Surg 2018 06;12(2):199-200

Department of Urology, UT Southwestern Medical Center, Dallas, TX, USA.

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http://dx.doi.org/10.1007/s11701-018-0794-5DOI Listing
June 2018

Effect of Differing Parameters on Irreversible Electroporation in a Porcine Model.

J Endourol 2018 04 30;32(4):338-343. Epub 2018 Jan 30.

1 Department of Urology, University of Texas Southwestern Medical Center , Dallas, Texas.

Introduction And Objective: Irreversible electroporation (IRE) is a new ablative technology to treat small renal masses. We evaluated differed ablation settings on lesion size and temperature changes in a porcine model.

Materials And Methods: After Institutional Animal Care and Use Committee approval, 36 laparoscopy-guided and 16 open ablations were performed on 13 domestic female pigs. Ablation parameters studied were voltage (1000 V/cm, 1500 V/cm, or 2000 V/cm), probe exposure (1.0 or 1.5 cm), and lesion size over time (survival) (0-, 7-, or 14 day). Temperature changes were monitored during open ablations with differed settings. Gross lesion size was measured, and histologic analysis with hematoxylin and eosin and nicotinamide adenine dinucleotide staining was performed.

Results: The 1000 V/cm ablations had no gross or histologic lesions. A factorial analysis of variance demonstrated that day (p = 0.56), exposure (p = 0.33), and voltage (p = 0.06) did not demonstrate statistical significance for affecting lesion size. For 1.0 cm probe exposure, 2000 V/cm did more closely approximate expected lesion size (p = 0.02) compared with 1500 V/cm. While significance was not seen for 1.5 cm probe exposure, 2000 V/cm often exceeded expected lesion volume. Only 1 of 4 temperature sensors, located adjacent to one of the IRE probes, noted a significant increase with increased voltage. However, all maximum temperatures remained less than 70°C.

Conclusions: Variation in lesion volume was seen with different ablation settings in this porcine model. Maximal energy and probe exposure settings should be utilized to ensure full coverage of target volume/mass, potentially without concern for thermal injury to renal collecting system or nearby structures.
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http://dx.doi.org/10.1089/end.2017.0495DOI Listing
April 2018

Re: Should every medical student have exposure to robotic surgery?

J Robot Surg 2018 03;12(1):1-2

Department of Urology, UT Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX, 75390, USA.

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http://dx.doi.org/10.1007/s11701-017-0764-3DOI Listing
March 2018

Robot-Assisted Versus Open Simple Prostatectomy for Benign Prostatic Hyperplasia in Large Glands: A Propensity Score-Matched Comparison of Perioperative and Short-Term Outcomes.

J Endourol 2017 11 26;31(11):1164-1169. Epub 2017 Sep 26.

Department of Urology, UT Southwestern Medical Center , Dallas, Texas.

Objective: To report the largest comparative analysis of robotic vs open simple prostatectomy (OSP) for large-volume prostate glands.

Materials And Methods: We retrospectively reviewed 103 patients that underwent open and 64 patients that underwent robotic simple prostatectomy from 2012 to 2016 at a single institution. A propensity score-matched analysis was performed with five covariates, including age, body mass index, race, Charlson comorbidity index, and prostate volume. Perioperative, postoperative, and functional outcomes were compared between groups.

Results: After propensity score matching there were 59 patients in each group available for comparison. There was no statistically significant difference between groups for all preoperative demographic variables. Robotic compared with OSP demonstrated a significant shorter average length of stay (LOS) (1.5 vs 2.6 days, p < 0.001), but longer mean operative time (161 vs 93 minutes, p < 0.001). The robotic approach was also associated with a lower estimated blood loss (339 vs 587 mL, p < 0.001) and lower percentage hematocrit drop (12.3% vs 19.5%, p = 0.001). Two patients required blood transfusions in the robot group compared with four in the open group, but this was not significant (p = 0.271). Improvements in maximal flow rate, International Prostate Symptom Score, quality of life, postvoid residual, and postoperative prostate-specific antigen levels were similar before and after surgery for both groups, but there was no difference between groups. There was no difference in complications between groups.

Conclusion: Robotic simple prostatectomy is a safe and effective treatment for the surgical management of benign prostatic hyperplasia. It provides similar function outcomes to the open approach; however, offers the advantage of reduced LOS and reduced blood loss.
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http://dx.doi.org/10.1089/end.2017.0489DOI Listing
November 2017

Molecular pathogenesis of human prostate basal cell hyperplasia.

Prostate 2017 May 10;77(13):1344-1355. Epub 2017 Aug 10.

Department of Urology, UT Southwestern Medical Center, Dallas, Texas.

Background: Understanding the molecular pathogenesis of distinct phenotypes in human benign prostatic hyperplasia (BPH) is essential to improving therapeutic intervention. Current therapies target smooth muscle and luminal epithelia for relief of lower urinary tract symptoms (LUTS) due to BPH, but basal cell hyperplasia (BCH) remains untargeted. The incidence of has been reported at 8-10%, but a molecular and cellular characterization has not been performed on this phenotype.

Methods: Using freshly digested tissue from surgical specimens, we performed RNA-seq analysis of flow cytometry-purified basal epithelia from 3 patients with and 4 patients without a majority BCH phenotype. qPCR was performed on 28 genes identified as significant from 13 non-BCH and 7 BCH specimens to confirm transcriptomic analysis. IHC was performed on several non-BCH and BCH specimens for 3 proteins identified as significant by transcriptomic analysis.

Results: A total of 141 human BPH specimens were analyzed for the presence of BCH. Clinical characteristics of non-BCH and BCH cohorts revealed no significant differences in age, PSA, prostate volume, medical treatment, or comorbidities. Quantitation of cellular subsets by flow cytometry in 11 BCH patients vs. 11 non-BCH patients demonstrated a significant increase in the ratio of basal to luminal epithelia in patients with BCH (P <0.05), but no significant differences in the total number of leukocytes. RNA-seq data from flow cytometry isolated basal epithelia from patients with and without BCH were subjected to gene set enrichment analysis of differentially expressed genes, which revealed increased expression of members of the epidermal differentiation complex. Transcriptomic data were complemented by immunohistochemistry for members of the epidermal differentiation complex, revealing a morphological similarity to other stratified squamous epithelial layers.

Conclusions: Increased expression of epidermal differentiation complex members and altered epithelial stratification resembles the progression of other metaplastic diseases. These data provide insight into the plasticity of the human prostate epithelium and suggest a classification of basal cell hyperplasia as a metaplasia.
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http://dx.doi.org/10.1002/pros.23394DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5580247PMC
May 2017

Safety and Efficacy of Stereotactic Ablative Radiation Therapy for Renal Cell Carcinoma Extracranial Metastases.

Int J Radiat Oncol Biol Phys 2017 05;98(1):91-100

Kidney Cancer Program, Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center, Dallas, Texas; Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas. Electronic address:

Purpose: Renal cell carcinoma is refractory to conventional radiation therapy but responds to higher doses per fraction. However, the dosimetric data and clinical factors affecting local control (LC) are largely unknown. We aimed to evaluate the safety and efficacy of stereotactic ablative radiation therapy (SAbR) for extracranial renal cell carcinoma metastases.

Methods And Materials: We reviewed 175 metastatic lesions from 84 patients treated with SAbR between 2005 and 2015. LC and toxicity after SAbR were assessed with Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1 and Common Terminology Criteria for Adverse Events (CTCAE) version 4.0. Predictors of local failure were analyzed with χ, Kaplan-Meier, and log-rank tests.

Results: In most cases (74%), SAbR was delivered with total doses of 40 to 60 Gy, 30 to 54 Gy, and 20 to 40 Gy in 5 fractions, 3 fractions, and a single fraction, respectively. The median biologically effective dose (BED) using the universal survival model was 134.5 Gy. The 1-year LC rate after SAbR was 91.2% (95% confidence interval, 84.9%-95.0%; median follow-up, 16.7 months). Local failures were associated with prior radiation therapy (hazard ratio [HR], 10.49; P<.0001), palliative-intent radiation therapy (HR, 4.63; P=.0189), spinal location (HR, 5.36; P=.0041), previous systemic therapy status (0-1 vs >1; HR, 3.52; P=.0217), and BED <115 Gy (HR, 3.45; P=.0254). Dose received by 99% of the target volume was the strongest dosimetric predictor for LC. Upon multivariate analysis, dose received by 99% of the target volume greater than BED of 98.7 Gy and systemic therapy status remained significant (HR, 0.12 and 3.64, with P=.0014 and P=.0472, respectively). Acute and late grade 3 toxicities attributed to SAbR were observed in 3 patients (1.7%) and 5 patients (2.9%), respectively.

Conclusions: SAbR demonstrated excellent LC of metastatic renal cell carcinoma with a favorable safety profile when an adequate dose and coverage were applied. Multimodality treatment with surgery should be considered for reirradiation or vertebral metastasis. A higher radiation dose may be required in patients who received previous systemic therapies.
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http://dx.doi.org/10.1016/j.ijrobp.2017.01.032DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5555369PMC
May 2017

Natural history of 'second' biochemical failure after salvage radiation therapy for prostate cancer: a multi-institution study.

BJU Int 2018 03 5;121(3):365-372. Epub 2017 Jul 5.

Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, TX, USA.

Objectives: To describe the natural history of prostate cancer in men who experience a second biochemical recurrence (BCR) after salvage radiotherapy (SRT) after prostatectomy.

Patients And Methods: After undergoing SRT at one of two institutions between 1986 and 2013, 286 patients experienced a second BCR, defined as two rises in prostate-specific antigen (PSA) of ≥0.2 ng/mL above nadir. Event rates for distant metastasis (DM) or freedom from DM (FFDM), castration-resistant prostate cancer (CRPC), prostate cancer-specific survival (PCSS), and overall survival (OS) were estimated using the Kaplan-Meier method. Cox regression was used for comparative analyses.

Results: At a median of 6.1 years after second BCR, DM, CRPC, PCSS and OS rates were 41%, 27%, 83% and 73%, respectively. On multivariable analysis, interval to second BCR <1 year (hazard ratio [HR] 2.66, 95% confidence interval [CI] 1.71-4.14; P < 0.001], Gleason score 8-10 (HR 1.65, 95% CI 1.07-2.54; P = 0.022), and concurrent ADT during SRT (HR 1.76, 95% CI 1.08-2.88; P = 0.024) were associated with FFDM, while PCSS was associated with interval to second BCR <1 year (HR 3.00, 95% CI 1.69-5.32; P < 0.001) and concurrent ADT during SRT (HR 2.15, CI 1.13-4.08; P = 0.019). These risk factors were used to stratify patients into three groups, with 6-year FFDM rates of 71%, 59% and 33%, and PCSS rates of 89%, 79%, and 65%, respectively.

Conclusion: Following second BCR after SRT, clinical progression is enriched in a subgroup of patients with prostate cancer, while others remain without DM for long intervals. Stratifying patients into risk groups using prognostic factors may aid counselling and future trial design.
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http://dx.doi.org/10.1111/bju.13926DOI Listing
March 2018

Axial Abdominal Imaging after Partial Nephrectomy for T1 Renal Cell Carcinoma Surveillance.

J Urol 2017 11 23;198(5):1021-1026. Epub 2017 Apr 23.

Department of Urology, University of Texas Southwestern Medical Center, Dallas, Texas. Electronic address:

Purpose: The overall recurrence rate of T1 renal cell carcinoma is low. We evaluated abdominal imaging after partial nephrectomy based on current guidelines for T1 renal cell carcinoma surveillance.

Materials And Methods: We retrospectively reviewed the records of patients with T1 renal cell carcinoma who underwent partial nephrectomy between 2006 and 2012 followed by abdominal imaging at our institution. Primary and secondary outcomes were the incidence and timing, respectively, of imaging diagnosed abdominal recurrences. A literature review was performed to summarize prior reports of recurrence incidence and timing after partial nephrectomy for T1 disease.

Results: A total of 160 patients with stage T1a and 37 with T1b underwent partial nephrectomy. Seven patients had an abdominal recurrence, including 3 with local and distant recurrences, and 4 with a metachronous contralateral kidney recurrence. The incidence of abdominal recurrence detected by imaging was higher in the T1b than in the T1a group (10.8% vs 1.9%, p = 0.024). Although it was not significant, median time to recurrence was earlier in T1b vs T1a cases (13 vs 37 months, p = 0.480). In each group recurrences developed after 3 years of suggested guideline surveillance. In the literature combined with the current study the time to median recurrence for T1b vs T1a was 24 vs 29 months (p = 0.226).

Conclusions: Recurrences detected by abdominal imaging developed earlier and more frequently in T1b than in T1a cases. Future recommendations for surveillance strategies after partial nephrectomy should distinguish T1a from T1b with less intense frequency of imaging for T1a. A longer period of surveillance should be considered since recurrences can develop beyond 3 years.
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http://dx.doi.org/10.1016/j.juro.2017.04.080DOI Listing
November 2017

A Novel Device to Prevent Stone Fragment Migration During Percutaneous Lithotripsy: Results from an In Vitro Kidney Model.

J Endourol 2016 11;30(11):1239-1243

1 Department of Urology, UT Southwestern Medical Center , Dallas, Texas.

Purpose: We developed a polyethylene sack (the PercSac) that fits over the shaft of a rigid nephroscope and is deployed into the collecting system to capture a stone and contain fragments during percutaneous nephrolithotomy (PCNL). We previously reported our results using the PercSac in a percutaneous cystolithopaxy model. In this study, we compare the efficiency of stone fragmentation with and without the PercSac in an anatomically correct in vitro PCNL model.

Materials And Methods: The PCNL model consisted of a human collecting system model created on a 3D printer. Ten BegoStones made in spherical molds of 2.0 cm diameter, matched for weight, were fragmented in the model using a 24F rigid nephroscope and an ultrasonic lithotripter, including five with and five without the PercSac. The total times for stone fragmentation and complete stone clearance, gross assessment of the stone-free status, and need for flexible nephroscopy to achieve a stone-free state were recorded.

Results: The median time for stone fragmentation was significantly shorter in the PercSac group compared with the control group (217 seconds [IQR = 169-255] vs 340 seconds [IQR = 310-356], [p = 0.028]). Likewise, the total time for complete stone clearance from the kidney was significantly shorter for the PercSac group (293 seconds [IQR = 244-347] vs 376 seconds [IQR = 375-480], [p = 0.047]). In one trial with the PercSac, residual dust remained in the kidney, while in all five trials without the PercSac small residual fragments remained. All trials without the PercSac required flexible nephroscopy with basket extraction to become stone free, while none of the trials with the PercSac required flexible nephroscopy for stone clearance.

Conclusions: Ultrasonic lithotripsy using the novel PercSac stone entrapment device is more efficient and efficacious than traditional ultrasonic lithotripsy in an in vitro PCNL model. The advantage may be even more pronounced during clinical PCNL where residual fragments migrate into difficult-to-access calices. Further in vivo testing is underway.
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http://dx.doi.org/10.1089/end.2016.0466DOI Listing
November 2016

New technologies in tumor ablation.

Curr Opin Urol 2016 May;26(3):248-53

aUT Southwestern Medical Center bUT Southwestern Medical Center, VA North Texas Health System, Dallas, Texas, USA.

Purpose Of Review: The application of ablative modalities for small renal masses continues to increase. In addition, multiple technologies continue to be studied for the treatment of these renal masses. This review focuses on new and emerging technologies so that the clinician can become more familiar with these modalities as they become available in clinical practice.

Recent Findings: Radiofrequency ablation (RFA) and cryoablation (cryo) continue to be the most often used ablative modalities for the treatment of small renal masses. In addition, they are the most thoroughly studied modalities leading to a set of well defined variables predicting successful ablation. Microwave ablation (MWA) and irreversible electroporation are newer modalities that offer theoretical advantages to RFA and cryo, although each differs in the specific advantage provided. Multiple animal studies have been performed with each modality; however, in both cases, the optimal device settings are not well defined. For MWA in particular, there are a significant number of systems available and within each system, there are an array of variables that can be modified, which influences the ablation zone size and shape. Other emerging technologies include stereotactic body radiation and high-intensity focused ultrasound, although each has limited data supporting their efficacy to date.

Summary: Ablation technology continues to multiply and evolve. Newer technologies such as MWA and irreversible electroporation are promising as they offer theoretical advantages to RFA and cryo. However, both require further studies to identify the optimal tumor characteristics and device settings leading to successful ablation.
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http://dx.doi.org/10.1097/MOU.0000000000000284DOI Listing
May 2016
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