Residency training program paradigms for teaching robotic surgical skills to urology residents

The advent of laparoscopic and robotic techniques for management of urologic malignancies marked the beginning of an ever-expanding array of minimally invasive options available to cancer patients. With the popularity of these treatment modalities, there is a growing need for trained surgical oncologists who not only have a deep understanding of the disease process and adept surgical skills, but also show technical mastery in operating the equipment used to perform these techniques. Establishing a robotic prostatectomy program is a tremendous undertaking for any institution, as it involves a huge cost, especially in the purchasing and maintenance of the robot. Residency programs often face many challenges when trying to establish a balance between costs associated with robotic surgery and training of the urology residents, while maintaining an acceptable operative time. Herein we describe residency training program paradigms for teaching robotic surgical skills to urology residents. Our proposed paradigm outlines the approach to compensate for the cost involved in robotic training establishment without compromising the quality of education provided. With the potential advantages for both patients and surgeons, we contemplate that robotic-assisted surgery may become an integral component of residency training programs in the future.

Abstract 2743: Accelerating the exploration of novel gene fusion events in prostate cancer

Gene fusions are regarded as cancer defining and often proven causative for cancer development. Up to 50% of prostate cancers harbor recurrent gene fusions, most often the TMPRSS2-ERG fusion. Other ETS gene fusions have been described involving ETV1, ETV4, and ETV5. The remaining prostate cancers are considered gene fusion negative based on fluorescence in-situ hybridization (FISH) or RT-PCR for known fusion specific transcripts. Paired-end RNA-sequencing is a novel approach to systematically interrogate for fusion transcripts in a global and un-biased manner. Herein, we exploit FusionSeq, a computational tool specifically developed to nominate chimeric transcripts from paired-end RNA-seq data, with the goal of identifying new gene fusions. Using FusionSeq we identified the androgen-induced genes FKBP5 and KLK2 as two novel 5′ fusion partners for the ETS genes ERG and ETV1, respectively. General transcriptional chimerism (e.g. read-through transcripts) without evidence of underlying genomic rearrangements is not restricted to prostate cancer but also occurs in the patient's matched benign prostate tissue, providing evidence for an extended complexity of the cellular transcriptome and supporting the notion that a gene's definition might have to be considered flexible. Finally, we report the identification and the validation of two novel gene fusions: i) the tumor suppressor and cell cycle regulator CDKN1A (p21WAF, CIP1) is fused to CD9; besides down-regulating p21 gene expression, the CDKN1A-CD9 fusion also alters the CD9 protein. ii) by fusing IKBKB (IKK2, IκB kinase beta subunit) to TNPO1 (transportin 1), IKBKB gene expression increases over other prostate cancers, suggesting a pronounced activation of the NFκB complex. Our results show that a small subset of prostate cancers may harbor private gene fusions involving tumor suppressors and regulators of pathways implicated in cancer development.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2743.

Abstract 1139: Complete characterization of prostate cancer genomes by massively parallel sequencing

Prostate cancer is the most common type of cancer diagnosed among men in the United States, accounting for 200,000 new cases and 27,000 deaths per year. Prior genetic studies have shown that chromosomal rearrangements comprise a major mechanism of oncogene activation in prostate cancer. For example, androgen-regulated gene fusions involving ETS family transcription factors are present in the majority of prostate cancers, yet the full repertoire of genomic alterations driving prostate carcinogenesis and progression remains unknown. Toward this end, recent technological advances have made it possible to characterize the full complement of somatic mutations in a single tumor through whole genome sequencing.

We are using massively parallel sequencing technology to characterize the complete genomes of several primary prostate adenocarcinomas at >30x coverage. All samples are high-grade primary tumors (Gleason grade 7 to 9) and include cases with and without known ETS family translocations. For each tumor, we are also obtaining >30x sequence coverage of matched normal DNA from blood of these same patients in order to determine the somatic component of the overall variation we observe. Our results indicate that translocations and other chromosomal rearrangements occur frequently in prostate cancer, at a rate of >100 per genome. Further, we have discovered many nonsynonymous sequence mutations (point mutations and indels) in each tumor, some of which may represent novel candidate drivers of tumor progression. The overall rate of somatic point mutations is approximately 1 per Megabase. Integrated analysis of all genomes reveals both recurrent and private alterations. Together, these results illuminate potential avenues for target discovery and demonstrate the unparalleled value in performing complete genome sequencing in this malignancy.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1139.

Visual cues as a surrogate for tactile feedback during robotic-assisted laparoscopic prostatectomy: posterolateral margin rates in 1340 consecutive patients

OBJECTIVE

To analyse consecutive cases of robotic-assisted laparoscopic prostatectomy (RALP), present the incidence of nerve-sparing-related positive surgical margins (SM+), include visual cues that might assist in smoothly changing to the robotic platform, and discuss the scientific rationale for 'intersensory integration' which might explain the 'reverse Braille' phenomenon, i.e. the ability to feel when vision is greatly enhanced, as the lack of tactile feedback during RALP is often cited as a disadvantage of robotic surgery, interfering with a surgeon's ability to make intraoperative oncological decisions.

PATIENTS AND METHODS

Data from 1340 consecutive patients undergoing RALP from one institution were analysed and trends for positive posterolateral SM+ (PLSM+) were correlated with oncological variables before and after RALP. A sample of patient slides were reviewed by a extramural pathologist. Multivariate regression modelling was used to compare the projected rates of PLSM+ vs the actual rate, given the effect of a conscious effort to use visual cues. Finally, video recordings of the procedure were systematically reviewed and correlated with anatomical and histopathological images in an integrated session involving the surgeon and the pathology team.

RESULTS

The incidence of PLSM+ was 2.1%, which gradually declined to 1.0% in the last 100 patients. The reduction in PLSM+ occurred despite an increased rate of high-risk tumours operated on during this period. Forecasting analysis showed that the actual PLSM+ rate declined by half in the most recent 1000 patients, due to an integrated effort involving the use of visual cues during surgery. The following visual cues were considered important; appreciation of periprostatic (lateral prostatic) fascial compartments; colour and texture of the tissue; periprostatic veins as a landmark for athermal dissection; signs of inflammation; and a freely separating bloodless plane showing loose shiny areolar tissue.

CONCLUSION

Adapting to the robotic platform is easy and there is no compromise of the oncological safety of this procedure. Experienced surgeons can use visual cues to assist during nerve-sparing RALP and achieve low PLSM+ rates.

Multiphoton microscopy of prostate and periprostatic neural tissue: a promising imaging technique for improving nerve-sparing prostatectomy

BACKGROUND AND PURPOSE

Various imaging modalities are under investigation for real-time tissue imaging of periprostatic nerves with the idea of improving the results of nerve-sparing radical prostatectomy. We explored multiphoton microscopy (MPM) for real-time tissue imaging of the prostate and periprostatic neural tissue in a male Sprague-Dawley rat model. The unique advantage of this technique is the acquisition of high-resolution images without necessitating any extrinsic labeling agent and with minimal phototoxic effect on tissue.

MATERIALS AND METHODS

The prostate and cavernous nerves were surgically excised from male Sprague-Dawley rats. The imaging was carried out using intrinsic fluorescence and scattering properties of the tissues without any exogenous dye or contrast agent. A custom-built MPM, consisting of an Olympus BX61WI upright frame and a modified MRC 1024 scanhead, was used. A femtosecond pulsed titanium/sapphire laser at 780-nm wavelength was used to excite the tissue; laser power under the objective was modulated via a Pockels cell. Second harmonic generation (SHG) signals were collected at 390 (+/-35 nm), and broadband autofluorescence was collected at 380 to 530 nm. The images obtained from SHG and from tissue fluorescence were then merged and color coded during postprocessing for better appreciation of details. The corresponding tissues were subjected to hematoxylin and eosin staining for histologic confirmation of the structures.

RESULTS

High-resolution images of the prostate capsule, underlying acini, and individual cells outlining the glands were obtained at varying magnifications. MPM images of adipose tissue and the neural tissues were also obtained. Histologic confirmation and correlation of the prostate gland, fat, cavernous nerve, and major pelvic ganglion validated the findings of MPM.

CONCLUSION

Real-time imaging and microscopic resolution of prostate and periprostatic neural tissue using MPM is feasible without the need for any extrinsic labeling agents. Integration of this imaging modality with operative technique has the potential to improve the precision of nerve-sparing prostatectomy.

Scientific and technical advances in continence recovery following radical prostatectomy

The advent of prostate-specific antigen screening has changed the global epidemiology of prostate cancer, with men being diagnosed with organ-confined cancer at a younger age. Radical prostatectomy with curative intent for these patients, while delivering excellent long-term survival outcomes, still has significant side effects, chiefly postprostatectomy incontinence. Increasing age, shorter pre- and post-operative membranous urethral length, anastomotic strictures, obesity, low surgeon volume, variations of surgical technique and previous prostate surgery have been reported as negative risk factors for delayed continence recovery and/or permanent incontinence following radical prostatectomy. Significant progress in elucidating the functional anatomy and physiology of the male continence mechanism from cadaveric and videourodynamic studies have enabled surgeons to propose innovative surgical techniques during radical prostatectomy for augmenting continence preservation and early return. These have included optimizing the preservation of urethral rhabdosphincter length; avoiding rhabdosphincter injury; posterior reconstruction of Denonvilliers' musculofascial plate; preservation of the bladder neck and internal sphincter; bladder neck intussusception; bladder neck mucosal eversion; preservation of the puboprostatic ligaments and arcus tendineus; and preservation of putative nerves supplying the continence mechanism. We review the scientific and technical advances in continence recovery following radical prostatectomy, identify the key principles undergirding early return of continence, highlight various treatment strategies for early and refractory postprostatectomy incontinence and describe our experience with a paradigm of these unified key principles. Increasing application of these principles in computer-aided (robotic), minimally invasive and minimal-access (i.e., single-port or natural orifice transluminal) approaches will hopefully enable patients to derive maximal benefit from curative prostatectomy while experiencing early return of continence in the not too distant future.

Prostate volume and the incidence of extraprostatic extension: is there a relation?

BACKGROUND AND PURPOSE

Extraprostatic extension (EPE) of tumor is an important prognostic indicator that has an impact on long-term survival after radical prostatectomy. We investigated whether the prostate size has any association with the tumor volume and the incidence of EPE.

PATIENTS AND METHODS

Seven hundred consecutive robot-assisted radical prostatectomy procedures performed by a single surgeon at a single center were studied. Preoperative parameters (demographic details, prostate-specific antigen (PSA) level, biopsy characteristics, and tumor volume) and the postoperative histopathologic details of the specimen (prostate volume, Gleason sum, EPE, and surgical margin status) were compared among the small prostate (< 40 cc), intermediate size (40-70 cc), and large prostate (> 70 cc) groups. Chi-square analysis was performed for comparison of groups with nominal variables while continuous variables were compared using analysis of variance. A double-sided P value of less than 0.05 was considered statistically significant.

RESULTS

A greater proportion of patients in the large prostate group had T(1c) tumor compared with those in the small prostate group (90.2% v 78.3%). Younger men and smaller prostates had lower preoperative PSA levels (P < 0.001). A significantly higher PSA density (0.16 v 0.07) and cancer density (0.0102 v 0.0025), however, was observed in patients with small prostates compared with those with large prostates. A total of 102 (14.6%) patients had EPE on the final pathologic analysis while 8.6% of the patients had positive surgical margins. Greater incidence of EPE was observed in the group with smaller prostates compared to those in the large prostate group (16.7% v 7.3%).

CONCLUSION

Small prostates have a higher cancer density and a greater incidence of EPE of tumor.

SLC45A3-ELK4 is a novel and frequent erythroblast transformation-specific fusion transcript in prostate cancer

Chromosomal rearrangements account for all erythroblast transformation-specific (ETS) family member gene fusions that have been reported in prostate cancer and have clinical, diagnostic, and prognostic implications. Androgen-regulated genes account for the majority of the 5' genomic regulatory promoter elements fused with ETS genes. TMPRSS2-ERG, TMPRSS2-ETV1, and SLC45A3-ERG rearrangements account for roughly 90% of ETS fusion prostate cancer. ELK4, another ETS family member, is androgen regulated, involved in promoting cell growth, and highly expressed in a subset of prostate cancer, yet the mechanism of ELK4 overexpression is unknown. In this study, we identified a novel ETS family fusion transcript, SLC45A3-ELK4, and found it to be expressed in both benign prostate tissue and prostate cancer. We found high levels of SLC45A3-ELK4 mRNA restricted to a subset of prostate cancer samples. SLC45A3-ELK4 transcript can be detected at high levels in urine samples from men at risk for prostate cancer. Characterization of the fusion mRNA revealed a major variant in which SLC45A3 exon 1 is fused to ELK4 exon 2. Based on quantitative PCR analyses of DNA, unlike other ETS fusions described in prostate cancer, the expression of SLC45A3-ELK4 mRNA is not exclusive to cases harboring a chromosomal rearrangement. Treatment of LNCaP cancer cells with a synthetic androgen (R1881) revealed that SLC45A3-ELK4, and not endogenous ELK4, mRNA expression is androgen regulated. Altogether, our findings show that SLC45A3-ELK4 mRNA expression is heterogeneous, highly induced in a subset of prostate cancers, androgen regulated, and most commonly occurs through a mechanism other than chromosomal rearrangement (e.g., trans-splicing).

Effect of socioeconomic factors on long-term mortality in men with clinically localized prostate cancer

OBJECTIVES

To examine the effect of socioeconomic factors on survival in black and white patients with local or regional prostate cancer.

METHODS

All cases (n = 2046) of clinically localized prostate cancer diagnosed from 1990 to 2000 at the Henry Ford Health System and the Henry Ford Medical Group, equal access health centers, were included. Data on the stage, grade, age at diagnosis, socioeconomic status, treatment given, comorbidities, and vital statistics were gathered from the Henry Ford Medical Group tumor registry and computerized databases, pathologic reports, patient charts, Surveillance, Epidemiology, and End Results database, and the national death registry. The endpoints were the overall and cancer-specific survival. Survival was calculated using Cox proportional hazards regression models.

RESULTS

Of the 2046 cases, 1243 were white and 803 were black. Black patients were more likely to have lower incomes, a greater baseline prostate-specific antigen level, and greater comorbidities. They were also more likely to undergo radiotherapy and less likely to undergo radical prostatectomy. Univariate analysis, with white race as the baseline hazard, showed that black patients had significantly increased cancer-specific (hazard ratio [HR] 1.47, 95% confidence interval [CI] 1.01-2.13) and overall (HR 1.29, 95% CI 1.09-1.53) mortality. However, adjusting for insurance status and income on multivariate analysis revealed no significant differences in cancer-specific (HR 1.04, 95% CI 0.66-1.64) and overall (HR 0.96, 95% CI 0.78-1.18) survival.

CONCLUSIONS

In this cohort, socioeconomic factors were sufficient to explain the disparity in survival between white and black patients. Survival differences disappeared after adjusting for income status on multivariate analysis.

Prevalence of Cryptosporidium andersoni: a molecular epidemiological survey among cattle in India

Cryptosporidiosis is an important and established cause of calfhood morbidity in bovines. The present communication reports the prevalence of Cryptosporidium infection among juvenile and adult cattle (6-24 months old) in India based on examination of faecal samples collected from 350 animals across three different agro-climatic regions of the country and further confirmation by a two-step nested PCR assay targeting 18S ssu rRNA gene. A total of 45 samples were positive for Cryptosoridium species by nested PCR assay. The PCR products were subjected to restriction fragment length polymorphism (RFLP) analysis using SspI and VspI restriction enzymes for species differentiation. The results showed that the species involved in all the samples found positive was Cryptosporidium andersoni. The overall prevalence rate was 12.85%, with highest occurrence in the northern states (14.37%) of the country. The animals between age group of 6-12 months were mostly affected (21.67%) and the season wise prevalence of infection was more during the hot and humid monsoon season (20.16%). The results clearly demonstrated that C. andersoni is the major Cryptosporidium species affecting juvenile and adult cattle in three agro-climatically different geographical regions of India. This is the first report on prevalence of C. andersoni in bovines from India the confirmation of which is based on application of nested PCR and PCR-RFLP based molecular tools.

A case of hereditary protein S deficiency presenting with cerebral sinus venous thrombosis and deep vein thrombosis at high altitude

A 35-year-old healthy male with no history of any past medical illness developed severe headache, vomiting and drowsiness while at high altitude (4,572 m) in the eastern Himalayan ranges. He was evacuated to a tertiary-care hospital where he was diagnosed to have cerebral sinus venous thrombosis (CSVT) on magnetic resonance imaging, with deep vein thrombosis (DVT) of his right popliteo-femoral vein on color Doppler study. Investigation for thrombophilia revealed protein S (PS) deficiency in this patient. Family screening revealed low levels of PS in two elder brothers. One brother had a history of 'stroke in young' at the age of 20 years with the other being asymptomatic. This established the hereditary nature of PS deficiency. We are not aware of any previously published report on hereditary PS deficiency combined with CSVT and DVT occurring at high altitude. However, 1 case of protein C deficiency with CSVT has been reported previously.

Prevalence and molecular characterization of bovine Cryptosporidium isolates in India

A survey based on PCR assay of 18S SSU rRNA gene revealed a 30.2% infection with Cryptosporidium spp., out of 457 faecal samples collected from neonatal bovine calves across three different regions of India. The PCR-RFLP pattern of the gene in all the positive cases established the species as Cryptosporidium parvum. Highest prevalence was recorded in the monsoon months (37.3%) and in the calves showing acute diarrhoea (32.3%). The calves below 15 days of age were mostly affected (45.1%). The infection was more prevalent in the northern parts (35.4%) of the country than in the eastern or southern parts. Results indicated that C. parvum was the only species of Cryptosporidium prevalent in bovine calves in three different geographical regions of India.

Anatomic Restoration Technique of Continence Mechanism and Preservation of Puboprostatic Collar: A Novel Modification to Achieve Early Urinary Continence in Men Undergoing Robotic Prostatectomy

OBJECTIVES

The puboprostatic ligaments, puboperinealis muscle, and arcus tendineus are all recognized as important for continence in men and women. This complex of ligaments, muscles, and tendineus aponeurosis acts in unison to provide continence and can be disrupted during robotic prostatectomy. We propose that preservation of the puboprostatic collar during robotic surgery will help to restore early continence in men undergoing robotic prostatectomy.

METHODS

We performed cadaveric studies in 10 fresh cadavers to devise strategies to leave intact the puboprostatic ligaments, muscular collar, and arcus tendineus supporting the continence mechanism. We developed reconstructive strategies to reconnect the ligaments to the urethrovesical anastomosis, reapproximated the muscles, and fixed the distal bladder to the arcus tendineus. These modifications were then attempted in 50 consecutive patients who underwent robotic prostatectomy for clinically localized prostate cancer. The patient-reported outcomes were then used to assess the efficacy of this procedure.

RESULTS

The technique was reproducible, and the average additional time taken for the final reconstruction was only 2 to 5 minutes. The continence rate was 29% in the first week, 62% at 6 weeks, 88% at 12 weeks, and 95% in 16 weeks after catheter removal. No other differences were found in the operative, oncologic, or perioperative outcomes.

CONCLUSIONS

This modification helped in the early return of continence. It is unlikely that the long-term results will be any different, but shortening the recovery time will have psychological, financial, and health-related quality-of-life benefits for the patients.

Anatomical foundations and surgical manoeuvres for precise identification of the prostatovesical junction during robotic radical prostatectomy

OBJECTIVE

To develop a technique to identify the bladder neck during robotic radical prostatectomy (RRP) using anatomical and patient studies, and to evaluate its efficacy during and after surgery.

PATIENTS AND METHODS

The data for this study were from 10 fresh cadaveric dissections and 50 consecutive athermal RRPs performed at our institution. We used a technique we term 'the bimanual bladder neck pinch'.

RESULTS

The technique helped us to identify the prostatovesical junction and to decrease the time required to dissect the bladder neck, and the time for urethrovesical anastomosis. Urinary continence requiring 0-1 pads was 29% at 1 week , 62% at 6 weeks, 88% at 12 weeks, and 95% at 16 weeks. No patient in the series had a clinically significant leak or urinary retention.

CONCLUSIONS

Our technique of the 'bimanual pinch' is easy to learn and has reduced the difficulty of bladder neck transection. It improved the outcome both during and after RRP in our series.

Athermal Robotic Technique of prostatectomy in patients with large prostate glands (>75 g): technique and initial results

OBJECTIVE

To report our experience with robotic radical prostatectomy (rRP) for prostate glands of >75 g, as this technique is developing rapidly.

PATIENTS AND METHODS

Between January 2005 and November 2005, 30 men with prostates of >75 g had rRP. Their clinicopathological and operative data were reviewed. Technical considerations for successful rRP in patients with large glands are discussed, including the importance of surgical exposure and multiple traction sutures.

RESULTS

The mean (range) specimen weight was 116.1 (75.3-346.0) g, the patient age 65.0 (56-72) years, the body mass index 28.4 (21-41) kg/m2, the preoperative International Prostate Symptom Score 10 (0-32), and the prostate-specific antigen (PSA) level 7.54 (1.9-20.1) ng/mL. The clinical stage was T1c in 26 men and T2a in four. The biopsy Gleason scores were 3 + 3 = 6 in 25 men, 3 + 4 = 7 in four and 4 + 3 = 7 in one. The mean (range) estimated blood loss was 208 (100-600) mL and the operative duration 193 (150-270) min. The cancer was organ-confined in all patients and all surgical margins were negative. The mean (range) duration of indwelling catheterization was 12.7 (11-14) days. There were no complications during or after rRP, and the PSA level was undetectable in all patients after surgery.

CONCLUSIONS

RP for patients with large prostates is technically challenging. The robotic approach does not appear to compromise oncological control. We show the feasibility of rRP for men with large glands.

Anatomy of autonomic nerve component in the male pelvis: the new concept from a perspective for robotic nerve sparing radical prostatectomy

The DaVinci Robot (Intuitive Surgical, Sunnyvale California) with its magnified 3-D vision and multi-jointed wristed instruments enabled us to perform radical prostatectomy with consideration for the pelvic anatomy. In the present paper, we review the pelvic autonomic neuroanatomy with respect to robotic prostatectomy and demonstrate the procedures and critical points of nerve-sparing robotic radical prostatectomy based on novel anatomic concepts. Microscopic and macroscopic data were acquired from 30 fresh and 25 fixed male cadavers. A video study of 205 surgeries was performed for establishing the anatomy relevant to robotic prostatectomy. From a practical standpoint, we could group the relevant neural tissue into three broad zones: (1) proximal neurovascular plate (PNP), (2) predominant neurovascular bundles (PNB), (3) accessory distal neural pathways (ANP). Autonomic ganglion cells existed widely not only in nerve components but also along the viscera. The critical areas of nerve sparing surgery were the distal end of PNP, the entire PNB, and the circumference of the apex. Interindividual differences of cell counts were evident in all sites. Based on these concepts, we established the Athermal Robotic Technique (ART) for nerve sparing prostatectomy. Surgical and oncological outcomes were not mature but feasible. These tri-zonal and ganglion cell concepts may be of benefit to new surgeons undertaking nerve-sparing robotic radical prostatectomy.