MicroSegNet: A deep learning approach for prostate segmentation on micro-ultrasound images

Micro-ultrasound (micro-US) is a novel 29-MHz ultrasound technique that provides 3-4 times higher resolution than traditional ultrasound, potentially enabling low-cost, accurate diagnosis of prostate cancer. Accurate prostate segmentation is crucial for prostate volume measurement, cancer diagnosis, prostate biopsy, and treatment planning. However, prostate segmentation on micro-US is challenging due to artifacts and indistinct borders between the prostate, bladder, and urethra in the midline. This paper presents MicroSegNet, a multi-scale annotation-guided transformer UNet model designed specifically to tackle these challenges. During the training process, MicroSegNet focuses more on regions that are hard to segment (hard regions), characterized by discrepancies between expert and non-expert annotations. We achieve this by proposing an annotation-guided binary cross entropy (AG-BCE) loss that assigns a larger weight to prediction errors in hard regions and a lower weight to prediction errors in easy regions. The AG-BCE loss was seamlessly integrated into the training process through the utilization of multi-scale deep supervision, enabling MicroSegNet to capture global contextual dependencies and local information at various scales. We trained our model using micro-US images from 55 patients, followed by evaluation on 20 patients. Our MicroSegNet model achieved a Dice coefficient of 0.939 and a Hausdorff distance of 2.02 mm, outperforming several state-of-the-art segmentation methods, as well as three human annotators with different experience levels. Our code is publicly available at https://github.com/mirthAI/MicroSegNet and our dataset is publicly available at https://zenodo.org/records/10475293.

Repair of lymphoperitoneal fistulae for chylous ascites following robotic-assisted partial nephrectomy: Anatomic foundation for left-sided predominance following renal surgery

Chylous ascites (CA) is a rare complication following renal surgery. Here we present the case of a 28-year-old female who developed CA after a robotic left partial nephrectomy. After failing conservative management, she underwent successful robotic-assisted diagnostic laparoscopy and ligation of lymphoperitoneal fistulae. The higher incidence of CA after left versus right-sided renal surgery may be explained by the para-aortic drainage of the intestinal lymphatic channels. Surgical intervention should be considered when conservative management fails.

[Source Analysis and Ecological Risk Assessment of Heavy Metals in the Arable Soil at the Geological High Background, Based on the Township Scale]

Due to the extensive development of carbonate rocks in southwest China, heavy metals are naturally occurring elements that have high natural background levels in the environment. Therefore, it is important to conduct ecological risk assessments and identify potential sources of heavy metals in the geological high background area. Based on the township scale, a total of 307 surface soil samples were collected in Qinglong Town, Fengjie County, Chongqing. The concentrations of As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn and pH were analyzed and determined. The spatial distribution and source of soil heavy metals were discussed using the geostatistical analysis and an absolute principal component score-multiple linear regression (APCS-MLR) model in the studied area. The results showed that the average values of seven heavy metals (As, Cd, Cr, Cu, Hg, Ni, and Zn) in the arable soil exceeded the background values of Chongqing, and the cumulative effect of Cd and As was obvious. The concentrations of Cd significantly exceededthe screening values in The Risk Control Standard for Soil Environmental Quality and Soil Pollution in Agricultural Land (GB 15618-2018), with the over-standard rates of 52.12%. The spatial characteristics of soil heavy metal contents exhibited a pattern of high in the south and low in the north. PCA and APCS-MLR modeling revealed that the contributions of natural sources to Cr, Cu, Ni, and Zn were 86.62%, 64.34%, 76.44%, and 85.46%, respectively. As, Pb, and Hg mainly derived from industrial activities, which accounted for 74.63%, 61.90%, and 73.49%, respectively, and Cd was affected by both natural sources and industrial activities (accounting for 47.74% and 39.56% of the total Cd content, respectively). The evaluation of the soil by the Nemerow comprehensive index (P) showed that Cd pollution was relatively serious, accounting for 27.04% of soil pollution. The potential ecological hazard index showed that Cd and Hg were the main ecological hazard elements, and the distribution range of RI was 51.77 to 2228, indicating mainly mild and moderate risks, and the moderate and above risk areas in the study area were mainly located around the southern industrial source area. Altogether, our results revealed that in the study area, the heavy metal pollution was mainly caused by industrial activities, and the heavy metal pollution caused by geological background was mainly light to moderate. In conclusion, the medium and above risk areas in the study area were mainly caused by mineral and industrial activities, whereas the heavy metal pollution caused by geological background was mainly light to moderate pollution.

Micro-Ultrasound Guided Transperineal Prostate Biopsy: A Clinic-Based Procedure

Prostate cancer is the most common solid malignancy in men and requires a biopsy for diagnosis. This manuscript describes a freehand micro-ultrasound guided transperineal technique performed under local anesthesia, which maintains accuracy, keeps patients comfortable, has low adverse events, and minimizes the need for disposables. Prior micro-ultrasound-guided transperineal techniques required general or spinal anesthesia. The key steps described in the protocol include (1) the placement of the local anesthesia, (2) micro-ultrasound imaging, (3) and the visualization of the anesthetic/biopsy needle while uncoupled from the insonation plane. A retrospective review of 100 patients undergoing this technique demonstrated a 68% clinically significant cancer detection rate. Pain scores were prospectively collected in a subset of patients (N = 20) and showed a median procedural pain score of 2 out of 10. The 30 day Grade III adverse event rate was 3%; one of these events was probably related to the prostate biopsy. Overall, we present a simple, accurate, and safe technique for performing a micro-ultrasound-guided transperineal prostate biopsy.

Florida-California Cancer Research, Education and Engagement (CaRE2) Health Equity Center: Structure, Innovations, and Initial Outcomes

INTRODUCTION

The Florida-California Cancer Research, Education, and Engagement (CaRE2) Health Equity Center is a triad partnership committed to increasing institutional capacity for cancer disparity research, the diversity of the cancer workforce, and community empowerment. This article provides an overview of the structure, process innovations, and initial outcomes from the first 4 years of the CaRE2 triad partnership.

METHODS

CaRE2 serves diverse populations in Florida and California using a "molecule to the community and back" model. We prioritize research on the complex intersection of biological, environmental, and social determinants health, working together with scientific and health disparities communities, sharing expertise across institutions, bidirectional training, and community outreach. Partnership progress and outcomes were assessed using mixed methods and four Program Steering Committee meetings.

RESULTS

Research capacity was increased through development of a Living Repository of 81 cancer model systems from minority patients for novel cancer drug development. CaRE2 funded 15 scientific projects resulting in 38 publications. Workforce diversity entailed supporting 94 cancer trainees (92 URM) and 34 ESIs (32 URM) who coauthored 313 CaRE2-related publications and received 48 grants. Community empowerment was promoted via outreaching to more than 3000 individuals, training 145 community cancer advocates (including 28 Community Scientist Advocates), and publishing 10 community reports. CaRE2 members and trainees together have published 639 articles, received 61 grants, and 57 awards.

CONCLUSION

The CaRE2 partnership has achieved its initial aims. Infrastructure for translational cancer research was expanded at one partner institution, and cancer disparities research was expanded at the two cancer centers.

Association between nuclear grade of renal cell carcinoma and the aorta-lesion-attenuation-difference

INTRODUCTION AND BACKGROUND

Several features noted on renal mass biopsy (RMB) can influence treatment selection including tumor histology and nuclear grade. However, there is poor concordance between renal cell carcinoma (RCC) nuclear grade on RMB compared to nephrectomy specimens. Here, we evaluate the association of nuclear grade with aorta-lesion-attenuation-difference (ALAD) values determined on preoperative CT scan.

METHODS AND MATERIALS

A retrospective review of preoperative CT scans and surgical pathology was performed on patients undergoing nephrectomy for solid renal masses. ALAD was calculated by measuring the difference in Hounsfield units (HU) between the aorta and the lesion of interest on the same image slice on preoperative CT scan. The discriminative ability of ALAD to differentiate low-grade (nuclear grade 1 and 2) and high-grade (nuclear grade 3 and 4) tumors was evaluated by sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and area under curve (AUC) using ROC analysis. Sub-group analysis by histologic sub-type was also performed.

RESULTS

A total of 368 preoperative CT scans in patients with RCC on nephrectomy specimen were reviewed. Median patient age was 61 years (IQR 52-68). The majority of patients were male, 66% (243/368). Tumor histology was chromophobe RCC in 7.6%, papillary RCC in 15.5%, and clear cell RCC in 76.9%. The majority, 69.3% (253/365) of tumors, were stage T1a. Nuclear grade was grade 1 in 5.46% (19/348), grade 2 in 64.7% (225/348), grade 3 in 26.2% (91/348), and grade 4 in 3.2% (11/348). Nephrographic ALAD values for grade 1, 2, 3, and 4 were 73.7, 46.5, 36.4, and 43.1, respectively (p = 0.0043). Nephrographic ALAD was able to differentiate low-grade from high-grade RCC with a sensitivity of 32%, specificity of 89%, PPV of 86%, and NPV of 36%. ROC analysis demonstrated the predictive utility of nephrographic ALAD to predict high- versus low-grade RCC with an AUC of 0.60 (95% CI 0.51-0.69).

CONCLUSION

ALAD was significantly associated with nuclear grade in our nephrectomy series. Strong specificity and PPV for the nephrographic phrase demonstrate a potential role for ALAD in the pre-operative setting that may augment RMB findings in assessing nuclear grade of RCC. Although this association was statistically significant, the clinical utility is limited at this time given the results of the statistical analysis (relatively poor ROC analysis). Sub-group analysis by histologic subtype yielded very similar diagnostic performance and limitations of ALAD. Further studies are necessary to evaluate this relationship further.

Robot-Assisted Radical Nephroureterectomy

First proposed by Kimball and Ferris in 1933 for the treatment of papillary tumors in the upper urinary tract, radical nephroureterectomy (RNU) with bladder cuff excision remains the gold standard for management of high-risk upper tract urothelial carcinoma involving the proximal ureter and/or pelvicaliceal system. Over three decades since the first description of laparoscopic RNU, minimally invasive approaches to RNU have continued to evolve and become increasingly utilized. More recently, robot-assisted RNU (RARNU) has increasingly become a viable approach. Specifically, RARNU affords a reduction in perioperative morbidity and improved convalescence as a minimally invasive approach, all while adhering to traditional open surgical principles and providing surgeons with improved technical ergonomics and streamlined operating room logistics, particularly with the advent of the da Vinci Xi platform. In this study, we describe our approach to transperitoneal RARNU, including indications, operating room setup, step-by-step surgical technique, and perioperative care.

Validation of aorta-lesion-attenuation difference on preoperative contrast-enhanced computed tomography scan to differentiate between malignant and benign oncocytic renal tumors

OBJECTIVES

We previously noted that the aorta-lesion-attenuation difference (ALAD) determined on CT scan discriminated well between chromophobe RCC and oncocytoma. The current evaluation seeks to validate these initial findings in a second cohort of nephrectomy patients.

METHODS

A retrospective review of preoperative CT scans and surgical pathology was performed on patients undergoing nephrectomy for small, solid renal masses. ALAD was calculated by measuring the difference in Hounsfield units (HU) between the aorta and the lesion of interest on the same image slice on preoperative CT scan. The discriminative ability of ALAD to differentiate malignant pathology from oncocytoma was evaluated by sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and area under curve (AUC) using ROC analysis.

RESULTS

Twenty-one preoperative CT scans and corresponding pathology reports were reviewed and included in the validation cohort. ALAD values were calculated during the excretory and nephrographic phases. Compared to the training cohort, patients in the validation cohort were significantly older (62 versus 59 years old), had larger tumors (3.7 versus 2.7 cm), and higher stage disease (59% versus 79% T1a disease). Nephrographic ALAD was able to differentiate malignant pathology from oncocytoma in the training and validation cohorts with a sensitivity of 84% versus 73%, specificity of 86% and 67%, PPV of 98% versus 91%, and NPV of 33% versus 35%. The AUC for malignant pathology versus oncocytoma in the validation cohort was 0.72 (95% CI 0.63-0.82). Nephrographic ALAD was able to differentiate chromophobe RCC from oncocytoma in the training and validation cohorts with a sensitivity of 100% versus 67%, specificity of 86% versus 67%, PPV of 75% versus 43%, and NPV of 100% versus 84%. The AUC for chromophobe RCC versus oncocytoma in the validation cohort was 0.72 (95% CI 0.48-0.96).

CONCLUSIONS

The ability of ALAD to discriminate between chromophobe RCC and oncocytoma was diminished in the validation cohort compared to the training cohort, but remained significant. The current findings support further investigation in the role of ALAD in the management of patients with indeterminate diagnoses of oncocytic neoplasm.

[Distribution Characteristics of Selenium in a Soil-Crop System and the Threshold of Selenium-Rich Soils]

In order to determine the distribution characteristics of Se in soil-crop systems, we carried out a study on the Se-rich soil threshold by collecting 8789 surface soils and 155 deep soils in the Qianjiang District of Chongqing City, China, and 141 corn seeds and 159 rice seeds (simultaneously collecting 141 and 159 corresponding root soil samples, respectively). We then analyzed the Se content, organic matter, S, Mn, TFe₂O₃, Al₂O₃, and K₂O in soils and crops, and soil pH. We also analyzed the surface layer using geostatistical methods and the distribution characteristics of Se in deep soils using multiple regression analysis to study the factors influencing the bioavailability of Se. Based on the contents of each component of root soil and the Se contents of crops, the Se rich threshold was examined. The results showed that the high-Se soils in the study area account for 32.72% of the total area; the distribution of Se contents in the surface and deep soils is mainly controlled by the parent material, the source of soil Se is stable, and the surface enrichment is obvious. The Se-rich rates of corn and rice were 75.35% and 46.81%, respectively, and soil organic matter and S content will limit the bioavailability of Se. If the planted crop is corn, it is recommended to use 0.3 mg·kg^-1 as the Se-rich soil threshold; if the planted crop is rice, when the soil pH is ≤ 7.5, it is recommended to use 0.3 mg·kg^-1 as the Se-rich soil threshold, while at a soil pH>7.5, it is recommended to use 0.4 mg·kg^-1 as the threshold. Similarly, if other large crops are planted in the study area, this method can also be used to carry out a study on the proposed Se-rich soil threshold.

Robot-Assisted Laparoscopic Resection of the Mesonephric Duct Remnant in a Patient with Zinner Syndrome

Introduction: A 17-year-old male with Zinner syndrome, a right seminal vesicle cyst, and a solitary left kidney presented with chronic pelvic pain. Previous surgeons had attempted robot-assisted laparoscopic seminal vesicle cyst aspiration and transurethral resection of the ejaculatory duct. Neither surgery provided sustained symptom relief. Abdominal and pelvic MRI showed a cystic structure lodged between the prostate and bladder. The right seminal vesicle, kidney, and ureter were not observed. Materials and Methods: A robot-assisted laparoscopic seminal vesiculectomy was planned. Dissection distal to the right vas deferens and between the bladder neck and prostate revealed a cystic seminal vesicle-like structure. Attached to this was a tubular structure coursing deep to the vas deferens from the right renal fossa. This was presumed to be a dysplastic ureter. The dysplastic ureter was transected from the seminal vesicle and the seminal vesicle was marsupialized to the deep pelvis. Proximally, the dysplastic ureter was transected and left open. Results: Histologic assessment of the specimen revealed an ∼12.1 cm tubular mesonephric remnant. The postoperative course was uncomplicated. At 6 months follow-up, the patient remains free of symptoms with preserved ejaculatory volume. Conclusions: Mesonephric duct abnormalities and symptoms present on a spectrum. We present a safe and effective resection of a mesonephric duct remnant from a 17-year-old male with Zinner syndrome. A robotic approach localized to the right allowed for excellent observation without compromising left-sided genitourinary anatomy. In males presenting with renal agenesis and pelvic symptoms, clinicians should be suspicious of Zinner syndrome and other mesonephric abnormalities.

Evaluation of Intraoperative Versus Postoperative Adjuvant Mitomycin C with Nephroureterectomy for Urothelial Carcinoma of the Upper Urinary Tract

Background:

Results of randomized trials support a single dose of intravesical chemotherapy following radical nephroureterectomy (RNU) for urothelial carcinoma.

Objective:

To evaluate the impact of the timing of intravesical mitomycin C (MMC) administration on the rate of bladder tumor recurrence (BTR) following RNU.

Methods:

We performed a retrospective review of patients who underwent RNU for upper tract urothelial carcinoma (UTUC) and received intravesical MMC between 2008 and 2016. Patients were categorized into two separate groups based on the timing of MMC administration: patients who received MMC intraoperatively (IO) and patients who received MMC on post-operative day 1 or later (PO). Our primary endpoint was BTR rate within the first year after surgery.

Results:

Fifty-one patients met our inclusion criteria: (IO: n = 30; PO: n = 21). There were no statistically significant differences in baseline characteristics of age, gender, race, surgical approach, tumor grade, tumor stage, surgical margins, nodal status, concomitant CIS, or history of bladder cancer. The median length of follow-up for each group was 22 months for IO and 12 months for PO (P = 0.10). The estimated probability of 1-year BTR rates for the IO and PO groups were 16% and 33%, respectively (p = 0.09). Cox analysis noted that the IO patients had a significantly lower rate of BTR in the first year postoperatively (HR = 0.113, 95% CI = 0.28–0.63, p = 0.01).

Conclusions:

The use of intraoperative MMC at the time of RNU was associated with a decrease in the risk of 1-year recurrence within the bladder.

[Pollution characteristics and health risk assessment of heavy metals in PM(2.5) in Lanzhou]

Objective: To understand the pollution characteristics and assess the pollution health risks of heavy metals in atmospheric PM(2.5) in Lanzhou. Methods: According to the regional characteristics of air pollution and industrial distribution characteristics in Lanzhou, atmospheric PM(2.5) was sampled monthly in Chengguan and Xigu Districts from January, 2015 to December, 2016. Detected the concentration of PM(2.5) and 12 kinds of elements (Sb, Al, As, Be, Cd, Cr, Hg, Pb, Mn, Ni, Se and Tl) by weighing method and inductively coupled plasma mass spectrometry. Enrichment factor and geo-accumulation index were used to describe the pollution characteristics, while health risk assessment was conducted using the recommended United States Environmental Protection Agency (USA EPA) model. The health risks of non-carcinogens were evaluated by non-cancer hazard quotient (HQ), the non-carcinogenic risk was considered to be negligible when HQ<1, HQ>1 meant a health risk. With a single contaminant cancer Risk value to evaluate the health risks of carcinogens, when the Risk value between 10(-6) to10(-4) as an acceptable level. Results: The daily average concentrations of PM(2.5) was 83.0 μg/m(3), 77.0 μg/m(3) in Chengguan and Xigu Districts, respectively, during the sampling periods, and the concentration of PM(2.5) in winter/spring was higher than summer/fall in both districts. The concentration of Al in PM(2.5) was the highest and other elements in descending order: Pb, Mn, As, Sb/Cd, Tl in both districts. Enrichment factor results showed that Al and Mn were mainly affected by natural factors, the rest of five elements were all typical man-made pollution elements and according to geo-accumulation index pollution level of Cd was the strongest in the winter. The results of health risk assessment showed that Mn had the highest non-cancer risks (HQ>1) and affected the health of the children seriously. HQ reached up to 2.44 and 1.79 in Chengguan and Xigu Districts, respectively. Pb, As, Sb, Cd had slight health impact (HQ<1), could be negligible. The cancer risks range of As, Cr were 6.33×10(-6) to 6.46×10(-5) between the acceptable level of risk (10(-6) to 10(-4)), which indicated that As and Cd had potential cancer-risks. Conclusions: The pollution level of atmospheric PM(2.5) and the heavy metals in it was still grim;the non-cancer risks caused by multiple metals on children deserved attention. Although the cancer risks of As and Cd were between the acceptable level of risk, the potential cancer risk still shall not be ignored.

Evaluation of the timing of adjuvant mitomycin C following nephroureterectomy for urothelial carcinoma of the upper urinary tract

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Background: Results of randomized trials support a single dose of intravesical chemotherapy (IVC) following radical nephroureterectomy (RNU) for urothelial carcinoma. Our goal was to evaluate the impact of the timing of intravesical mitomycin C (MMC) administration on the rate of bladder tumor recurrence (BTR) following RNU. Methods: After obtaining IRB approval, we performed a retrospective review of patients who underwent RNU for upper tract urothelial carcinoma (UTUC) and received intravesical MMC between 2008 and 2016 at our institution. Patients were categorized into two separate groups based on the timing of MMC administration: (1) patients who received MMC on the day of surgery (POD0) and (2) patients who received MMC on post-operative day 1 or later (POD1). Our primary endpoint was BTR rate within the first year after surgery. Our secondary endpoint was overall BTR rate. Results: Fifty-one patients met our inclusion criteria: (POD0: n = 30; POD1: n = 21). Mean length of follow-up for each group was 22.1 and 12.5 months, respectively (p = 0.02). There were no statistically significant differences in baseline characteristics of age, gender, race, surgical approach, tumor grade, tumor stage, surgical margins, nodal status, concomitant CIS, or history of bladder cancer. BTR rates at 1 year for the POD0 and POD1 groups were 16% and 33%, respectively (p = 0.17). Overall BTR rates were 23% and 33%, respectively (p = 0.43). Multivariate analysis noted that the POD0 patients had a significantly lower rate of BTR in the first year postoperatively (HR = 0.082, 95% CI = 0.01-0.56, p = 0.01). Other factors that were associated with a higher rate of BTR within the first year were open surgery (HR = 7.9, 95% CI = 1.18-53.88, p = 0.03), positive surgical margins (HR = 37.9, 95% CI = 1.74-825.35, p = 0.02), and concomitant CIS (HR = 10.8, 95% CI = 1.08-108.72). Conclusions: Our results suggest that the timing of intravesical MMC administration may impact the rate of BTR following RNU for urothelial carcinoma. This is the first study of its kind to attempt to identify the importance of timing of MMC administration relative to BTR following RNU. Further prospective studies are warranted to validate our current findings.

Using aorta lesion attenuation difference (ALAD) on preoperative contrast-enhanced CT scan to differentiate between malignant and benign renal tumors

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Background: To evaluate the ability of Aorta−Lesion−Attenuation−Difference (ALAD) to differentiate malignant renal tumors from renal oncocytomas. Methods: A retrospective review of preoperative CT scans and surgical pathology from robotic assisted partial nephrectomy specimens obtained by a single surgeon was performed. ALAD was calculated by measuring the difference in Hounsfield units (HU) between the aorta and the lesion of interest on the same image slice in the nephrographic phase on preoperative CT scan. The discriminative ability of ALAD to differentiate malignant pathology from oncocytoma was evaluated by sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and area under curve (AUC) using ROC analysis. Results: A total of 218 preoperative CT scans and corresponding pathology reports were reviewed. Pathology review revealed 22 oncocytomas (10.1%), 11 chromophobe RCC (5%), 37 papillary RCC (17%), and 148 clear cell RCC (67.9%). ALAD was able to differentiate malignant pathology from oncocytoma using a HU threshold of 24 with a sensitivity of 84%, specificity of 86%, PPV of 98%, and NPV of 33%. The AUC for malignant pathology versus oncocytoma was 0.86 (95% CI 0.77−0.96). Subgroup analysis showed that ALAD was able to differentiate chromophobe RCC from oncocytoma using a HU threshold of 24 with a sensitivity of 100%, specificity of 86%, PPV of 75%, and a NPV of 100%. The AUC for chromophobe RCC versus oncocytoma was 0.98 (95% CI 0.91−1.00). Conclusions: ALAD measurements based upon preoperative CT scans provide good discrimination between malignant renal tumors and oncocytomas, potentially decreasing the need for biopsy in certain patients. ALAD also discriminates well between chromophobe RCC and oncocytoma, which may aid in the management of patients with indeterminate diagnoses of oncocytic neoplasm on biopsy. Further validation of ALAD will be necessary prior to routine use in clinical practice.

Nightly sildenafil use after radical prostatectomy has adverse effects on urinary convalescence: Results from a randomized trial of nightly vs on-demand dosing regimens

INTRODUCTION

This is a report on urinary function results from a randomized trial of nightly versus on-demand sildenafil after nerve-sparing radical prostatectomy (RP), a secondary objective. We analyzed the effects of these sildenafil administration schemes on urinary health-related quality of life after RP.

METHODS

In total, 100 potent men were equally randomized to nightly and on-demand sildenafil 50 mg after minimally-invasive RP for 1 year. Health-related quality of life questionnaires were administered at various postoperative intervals. Urinary function was assessed using appropriate expanded prostate cancer index composite (EPIC) subscales. Analyses of covariance and linear mixed-effects modeling were used to compare the effects of treatment over time on urinary recovery, controlling for age, nerve-sparing score, and time from surgery.

RESULTS

The nightly (n = 50) and on-demand (n = 50) sildenafil groups were well-matched at baseline. Nightly sildenafil patients had worse EPIC urinary bother and urinary irritative/obstructive subscale scores at 3 and 6 months after RP, even after controlling for multiple variables. On mixed-model analyses, the differences between groups for these EPIC subscales (4.9 and 2.5, respectively) were greater than documented thresholds for clinical significance. Increasing nerve-sparing score was associated with improvements in EPIC urinary summary, bother, incontinence, and function scores; time from surgery was associated with improvements in all EPIC urinary health-related quality of life subscales.

CONCLUSIONS

In this specific population and drug dose, we found that on-demand short-acting phosphodiesterase-5 inhibitor (PDE5i) dosing may be more effective after RP to maximize early urinary health-related quality of life. In preoperatively potent men, nightly sildenafil 50 mg impaired urinary health-related quality of life more than on-demand use in the early months after nerve-sparing RP, independent of effects on urinary continence.

Crowdsourcing Assessment of Surgeon Dissection of Renal Artery and Vein During Robotic Partial Nephrectomy: A Novel Approach for Quantitative Assessment of Surgical Performance

INTRODUCTION

We sought to describe a methodology of crowdsourcing for obtaining quantitative performance ratings of surgeons performing renal artery and vein dissection of robotic partial nephrectomy (RPN). We sought to compare assessment of technical performance obtained from the crowdsourcers with that of surgical content experts (CE). Our hypothesis is that the crowd can score performances of renal hilar dissection comparably to surgical CE using the Global Evaluative Assessment of Robotic Skills (GEARS).

METHODS

A group of resident and attending robotic surgeons submitted a total of 14 video clips of RPN during hilar dissection. These videos were rated by both crowd and CE for technical skills performance using GEARS. A minimum of 3 CE and 30 Amazon Mechanical Turk crowdworkers evaluated each video with the GEARS scale.

RESULTS

Within 13 days, we received ratings of all videos from all CE, and within 11.5 hours, we received 548 GEARS ratings from crowdworkers. Even though CE were exposed to a training module, internal consistency across videos of CE GEARS ratings remained low (ICC = 0.38). Despite this, we found that crowdworker GEARS ratings of videos were highly correlated with CE ratings at both the video level (R = 0.82, p < 0.001) and surgeon level (R = 0.84, p < 0.001). Similarly, crowdworker ratings of the renal artery dissection were highly correlated with expert assessments (R = 0.83, p < 0.001) for the unique surgery-specific assessment question.

CONCLUSIONS

We conclude that crowdsourced assessment of qualitative performance ratings may be an alternative and/or adjunct to surgical experts' ratings and would provide a rapid scalable solution to triage technical skills.

Fiber-Optic Confocal Laser Endomicroscopy of Small Renal Masses: Toward Real-Time Optical Diagnostic Biopsy

PURPOSE

The incidental detection of small renal masses is increasing. However, not all require aggressive treatments as up to 20% are benign and the majority of malignant tumors harbor indolent features. Improved preoperative diagnostics are needed to differentiate tumors requiring aggressive treatment from those more suitable for surveillance. We evaluated and compared confocal laser endomicroscopy with standard histopathology in ex vivo human kidney tumors as proof of principle towards diagnostic optical biopsy.

MATERIALS AND METHODS

Patients with a solitary small renal mass scheduled for partial or radical nephrectomy were enrolled in study. Two kidneys were infused with fluorescein via intraoperative intravenous injection and 18 tumors were bathed ex vivo in dilute fluorescein prior to confocal imaging. A 2.6 mm confocal laser endomicroscopy probe was used to image tumors and surrounding parenchyma from external and en face surfaces after specimen bisection. Confocal laser endomicroscopy images were compared to standard hematoxylin and eosin analysis of corresponding areas.

RESULTS

Ex vivo confocal laser endomicroscopy imaging revealed normal renal structures that correlated well with histology findings. Tumor tissue was readily distinguishable from normal parenchyma, demonstrating features unique to benign and malignant tumor subtypes. Topical fluorescein administration provided more consistent confocal laser endomicroscopy imaging than the intravenous route. Additionally, en face tumor imaging was superior to external imaging.

CONCLUSIONS

We report what is to our knowledge the first feasibility study using confocal laser endomicroscopy to evaluate small renal masses ex vivo and provide a preliminary atlas of images from various renal neoplasms with corresponding histology. These findings serve as an initial and promising step toward real-time diagnostic optical biopsy of small renal masses.

Robotic distal ureterectomy with psoas hitch and ureteroneocystostomy: Surgical technique and outcomes

Use of the da Vinci^® surgical robotic system has expanded to numerous upper and lower urinary tract procedures. We describe our surgical technique and perioperative outcome of robotic distal ureterectomy with psoas hitch and ureteroneocystostomy for distal ureteral pathologies. Eight patients with a median age of 69.5 years old underwent robotic distal ureterectomy with psoas hitch and ureteroneocystostomy between April 2009 and August 2014. The entirety of all cases was performed robotically by a single surgeon at a tertiary academic medical center. Median operative time was 285 min (range: 210-360 min), estimated blood loss was 50 mL (range: 50-75 mL) and median length of hospital stay was 2.5 days (range: 1-6 days). There was one post-operative complication, a readmission for dehydration (Clavien I). It suggests that robotic distal ureterectomy with psoas hitch and ureteroneocystostomy is a safe and effective minimally invasive alternative for patients with distal ureteral pathology.

Xp11 Translocation Renal Cell Carcinoma: Unusual Variant Masquerading as Upper Tract Urothelial Cell Carcinoma

Xp11 translocation renal cell carcinoma (TRCC) is a rare subtype of renal cell carcinoma characterized by chromosomal translocations involving the TFE3 gene located at the Xp11.2 locus. Initial cases were more common in children, but cases in older adults have begun to accrue and suggest a relatively more aggressive course. We report a case of Xp11 TRCC in a 63-year-old female patient with initial presentation mimicking upper urinary tract urothelial cell carcinoma, with biopsy proving TRCC. She underwent a radical nephrectomy and paracaval lymph node dissection and is followed up with the intent to initiate vascular endothelial growth factor–targeted therapy in case of recurrence.

Perioperative outcomes of robot-assisted nephroureterectomy for upper urinary tract urothelial carcinoma: a multi-institutional series

OBJECTIVE

To review a multi-institutional series of robot-assisted nephroureterectomy (RANU) for management of upper urinary tract urothelial carcinoma (UUTUC) with respect to technique and perioperative outcomes.

PATIENTS AND METHODS

Between May 2007 and July 2011, 43 RANU were performed at three institutions for UUTUC with review of perioperative outcomes. A three- or four-armed robotic technique was used in all cases based on surgeon preference and the entirety of all procedures was performed using the robot-assisted technique. Single and two robot-docking techniques are described.

RESULTS

The mean (range) operating time was 247 (128-390) min, blood loss was 131 (10-500) mL and the median (range) length of stay was 3 (2-87) days. Pathology was pTa in nine patients, pT1 in 14 patients, pT2 in three patients, pT3 in 15 patients and pT4 in two patients. Lymph node dissection was performed in 22 patients (51%) with a mean (range) lymph node count of 11 (4-23). There were six postoperative complications: bleeding requiring a blood transfusion (grade II), splenic bleeding (grade IV), two cases of pneumonia (grade II) and two cases of rhabdomyolysis (grades II and IV). Nine recurrences (six bladder, two within the retroperitoneum and one in the contralateral collecting system) have been found to date on routine surveillance with a mean follow-up of 9 months.

CONCLUSIONS

RANU is a feasible alternative to laparoscopic and open techniques. Particular steps of the operation including sutured closure of the cystotomy and regional lymphadenectomy are facilitated with the use of robot-assisted surgery. Long-term outcomes are necessary to assess the relative efficacy of these approaches to more established techniques; however, early perioperative outcomes appear promising.

Nightly vs on-demand sildenafil for penile rehabilitation after minimally invasive nerve-sparing radical prostatectomy: results of a randomized double-blind trial with placebo

OBJECTIVES

To clarify the role of phosphodiesterase type 5 (PDE5) inhibitors in post-prostatectomy penile rehabilitation (PPPR). To compare nightly and on-demand use of PDE5 inhibitors after nerve-sparing minimally invasive radical prostatectomy (RP).

PATIENTS AND METHODS

We conducted a single-institution, double-blind, randomized controlled trial of nightly vs on-demand 50-mg sildenafil citrate after nerve-sparing minimally invasive RP. A total of 100 preoperatively potent men, aged <65 years, with scores on the Erectile Function domain of the International Index of Erectile Function (IIEF-EF) ≥26, underwent nerve-sparing surgery. The patients were randomized to either nightly sildenafil and on-demand placebo (nightly sildenafil group), or on-demand sildenafil and nightly placebo (on-demand sildenafil group; maximum on-demand dose six tablets/month) for 12 months. Patients then underwent a 1-month washout period. Validated measures of erectile function (IIEF-EF score and the Expanded Prostate Cancer Index Composite [EPIC]) were compared between treatment groups over the entire 13-month time course, using multivariable mixed linear regression models.

RESULTS

The treatment groups were well matched preoperatively (mean age 54.3 vs 54.6 years, baseline IIEF-EF score 29.4 vs 29.3, for the nightly vs the on-demand sildenafil groups, respectively). No significant differences were found in erectile function between treatments (nightly vs on-demand sildenafil) at any single timepoint after RP, after adjusting for potential confounding factors. When evaluated over all timepoints simultaneously, no significant effects of treatment group (nightly vs on-demand sildenafil) were found on recovery of potency, as assessed by absolute IIEF-EF scores (P = 0.765), on percentage of men returning to an IIEF-EF score >21 (P = 0.830), or on IIEF-EF score recovery to a percentage of baseline value (P = 0.778). When evaluated over all timepoints simultaneously, no significant effects of treatment group were found on secondary endpoints such as assessment of potency (including EPIC item 59 response 'erections firm enough for intercourse'), attempted intercourse frequency or confidence.

CONCLUSIONS

Erectile recovery up to 1 year after RP does not differ between previously potent men who use sildenafil nightly compared to on-demand. This trial does not support chronic nightly sildenafil as being any better than on-demand sildenafil for use in penile rehabilitation after nerve-sparing minimally invasive RP.

Ultrasound elastography as a tool for imaging guidance during prostatectomy: initial experience

BACKGROUND

During laparoscopic or robotic assisted laparoscopic prostatectomy, the surgeon lacks tactile feedback which can help him tailor the size of the excision. Ultrasound elastography (USE) is an emerging imaging technology which maps the stiffness of tissue. In the paper we are evaluating USE as a palpation equivalent tool for intraoperative image guided robotic assisted laparoscopic prostatectomy.

MATERIAL/METHODS

Two studies were performed: 1) A laparoscopic ultrasound probe was used in a comparative study of manual palpation versus USE in detecting tumor surrogates in synthetic and ex-vivo tissue phantoms; N=25 participants (students) were asked to provide the presence, size and depth of these simulated lesions, and 2) A standard ultrasound probe was used for the evaluation of USE on ex-vivo human prostate specimens (N=10 lesions in N=6 specimens) to differentiate hard versus soft lesions with pathology correlation. Results were validated by pathology findings, and also by in-vivo and ex-vivo MR imaging correlation.

RESULTS

In the comparative study, USE displayed higher accuracy and specificity in tumor detection (sensitivity=84%, specificity=74%). Tumor diameters and depths were better estimated using USE versus with manual palpation. USE also proved consistent in identification of lesions in ex-vivo prostate specimens; hard and soft, malignant and benign, central and peripheral.

CONCLUSIONS

USE is a strong candidate for assisting surgeons by providing palpation equivalent evaluation of the tumor location, boundaries and extra-capsular extension. The results encourage us to pursue further testing in the robotic laparoscopic environment.

Leveraging virtual humans to effectively prepare learners for stressful interpersonal experiences

Stressful interpersonal experiences can be difficult to prepare for. Virtual humans may be leveraged to allow learners to safely gain exposure to stressful interpersonal experiences. In this paper we present a between-subjects study exploring how the presence of a virtual human affected learners while practicing a stressful interpersonal experience. Twenty-six fourth-year medical students practiced performing a prostate exam on a prostate exam simulator. Participants in the experimental condition examined a simulator augmented with a virtual human. Other participants examined a standard unaugmented simulator. Participants reactions were assessed using self-reported, behavioral, and physiological metrics. Participants who examined the virtual human experienced significantly more stress, measured via skin conductance. Participants stress was correlated with previous experience performing real prostate exams; participants who had performed more real prostate exams were more likely to experience stress while examining the virtual human. Participants who examined the virtual human showed signs of greater engagement; non-stressed participants performed better prostate exams while stressed participants treated the virtual human more realistically. Results indicated that stress evoked by virtual humans is linked to similar previous real-world stressful experiences, implying that learners real-world experience must be taken into account when using virtual humans to prepare them for stressful interpersonal experiences.

Expansion of CCR8(+) inflammatory myeloid cells in cancer patients with urothelial and renal carcinomas

PURPOSE

Chemokines are involved in cancer-related inflammation and malignant progression. In this study, we evaluated expression of CCR8 and its natural cognate ligand CCL1 in patients with urothelial carcinomas of bladder and renal cell carcinomas.

EXPERIMENTAL DESIGN

We examined CCR8 expression in peripheral blood and tumor tissues from patients with bladder and renal carcinomas. CCR8-positive myeloid cells were isolated from cancer tissues with magnetic beads and tested in vitro for cytokine production and ability to modulate T-cell function.

RESULTS

We show that monocytic and granulocytic myeloid cell subsets in peripheral blood of patients with cancer with urothelial and renal carcinomas display increased expression of chemokine receptor CCR8. Upregulated expression of CCR8 is also detected within human cancer tissues and primarily limited to tumor-associated macrophages. When isolated, CD11b(+)CCR8(+) cell subset produces the highest levels of proinflammatory and proangiogenic factors among intratumoral CD11b myeloid cells. Tumor-infiltrating CD11b(+)CCR8(+) cells selectively display activated Stat3 and are capable of inducing FoxP3 expression in autologous T lymphocytes. Primary human tumors produce substantial amounts of the natural CCR8 ligand CCL1.

CONCLUSIONS

This study provides the first evidence that CCR8(+) myeloid cell subset is expanded in patients with cancer. Elevated secretion of CCL1 by tumors and increased presence of CCR8(+) myeloid cells in peripheral blood and cancer tissues indicate that CCL1/CCR8 axis is a component of cancer-related inflammation and may contribute to immune evasion. Obtained results also implicate that blockade of CCR8 signals may provide an attractive strategy for therapeutic intervention in human urothelial and renal cancers.

Linear and non-linear relationships between soil sorption and hydrophobicity

The relationship between log K (oc) and log P was examined by use of a large dataset. For most of the hydrophobic compounds (e.g. 0.5 < log P < 7.5), the organic carbon content plays a dominant role in soil sorption and the sorption coefficient is linearly related to the octanol/water partition coefficient. For hydrophilic compounds (e.g. log P < 0.5), hydrophobic sorption becomes less significant. The hydrophilic contribution to sorption is equal to, or higher than, the hydrophobic contribution to sorption, resulting in the observed K (oc) values being higher than those predicted from their log P values. For highly hydrophobic compounds (e.g. log P > 7.5), log K (oc) decreases with increasing hydrophobicity because of a lack of chemical availability due to low solubility. A linear solvation energy relationship shows that the sorption potential increases with increasing molecular size by increasing the dispersion interactions between the chemical and soil organic phase. The sorption potential decreases with increase in the basicity of hydrophobic compounds by increasing the H-bonding of chemicals with water. Principal component analysis shows that the octanol/water system is the closest system, but not an ideal surrogate, to describe the soil sorption for hydrophobic compounds as compared with other solvent/water partition systems.

Tumor-associated macrophages mediate immunosuppression in the renal cancer microenvironment by activating the 15-lipoxygenase-2 pathway

Renal cell carcinoma (RCC), the most common human kidney cancer, is frequently infiltrated with tumor-associated macrophages (TAM) that can promote malignant progression. Here, we show that TAMs isolated from human RCC produce substantial amounts of the proinflammatory chemokine CCL2 and immunosuppressive cytokine IL-10, in addition to enhanced eicosanoid production via an activated 15-lipoxygenase-2 (15-LOX2) pathway. TAMs isolated from RCC tumors had a high 15-LOX2 expression and secreted substantial amounts of 15(S)-hydroxyeicosatetraenoic acid, its major bioactive lipid product. Inhibition of lipoxygenase activity significantly reduced production of CCL2 and IL-10 by RCC TAMs. In addition, TAMs isolated from RCC were capable of inducing in T lymphocytes, the pivotal T regulatory cell transcription factor forkhead box P3 (FOXP3), and the inhibitory cytotoxic T-lymphocyte antigen 4 (CTLA-4) coreceptor. However, this TAM-mediated induction of FOXP3 and CTLA-4 in T cells was independent of lipoxygenase and could not be reversed by inhibiting lipoxygenase activity. Collectively, our results show that TAMs, often present in RCCs, display enhanced 15-LOX2 activity that contributes to RCC-related inflammation, immunosuppression, and malignant progression. Furthermore, we show that TAMs mediate the development of immune tolerance through both 15-LOX2-dependent and 15-LOX2-independent pathways. We propose that manipulating LOX-dependent arachidonic acid metabolism in the tumor microenvironment could offer new strategies to block cancer-related inflammation and immune escape in patients with RCC.

Comparison of outcomes between pure laparoscopic vs robot-assisted laparoscopic radical prostatectomy: a study of comparative effectiveness based upon validated quality of life outcomes

OBJECTIVE

To compare perioperative, oncological and functional outcomes of laparoscopic radical prostatectomy (LRP) and robot-assisted laparoscopic radical prostatectomy (RALP) with emphasis on health-related quality of life (HRQOL) data as few studies exist.

PATIENTS AND METHODS

Patients underwent RALP or LRP by a single, fellowship trained surgeon with a standard clinical care pathway. HRQOL data using the Expanded Prostate Cancer Index Composite (EPIC) were collected at 0, 3, 6 and 12 months after 175 consecutive LRP and 174 RALP procedures. Urinary and sexual function outcomes were compared using two methods: (1) EPIC summary/subscale analyses described as percent return to baseline function and (2) traditional single-question analysis.

RESULTS

The two groups were statistically similar with respect to demographics, clinical stage, perioperative outcomes, stage-specific surgical margin rates, and baseline urinary and sexual function scores. There was no statistical difference in postoperative urinary function between RALP and LRP using EPIC or single-question analyses at 3, 6 and 12 months. EPIC questionnaire data showed a greater return to baseline sexual function over time (mixed model analysis) in RALP than in LRP patients who had a bilateral nerve sparing procedure (Sexual Summary Score, P= 0.005; Sexual Function and Bother Subscales, P= 0.007). Using EPIC, RALP patients receiving a bilateral nerve sparing procedure showed improved percent return to baseline potency at 3 and 6 months (P < 0.025) compared with LRP patients, but had similar outcomes at 12 months (73.7% vs 66.2%, P= 0.3). Single-question analysis suggested improved potency after RALP compared with LRP, with a greater percentage of RALP patients reporting successful sexual intercourse in the past 4 weeks (87.5% vs 66.7% at 12 months, P= 0.06).

CONCLUSIONS

When comparing surgical techniques, RALP and LRP groups showed statistically similar postoperative urinary function outcomes. RALP patients had an earlier return of sexual function when compared with LRP patients after a bilateral nerve sparing procedure.

The NOTES approach to management of urinary bladder injury

BACKGROUND AND OBJECTIVES

Inadvertent bladder injury is a potential complication of various urological and pelvic surgeries. Bladder injury can also be a complication of natural orifice transluminal endoscopic surgery (NOTES). The aim of this study was to test the feasibility of a NOTES approach to repair bladder lacerations in a blinded porcine study.

METHODS

Intentional bladder lacerations were made to mimic accidental injury during NOTES in 7 pigs. In 3 animals, the site of bladder injury was identified and repaired by a blinded endoscopist. Bladder laceration and transluminal access sites were closed with Endoclips. Leak test was performed to confirm adequate closure. Survival animals were monitored postoperatively and surgical sites were inspected for abscess, bleeding, or damage to surrounding structures at necropsy.

RESULTS

Complete endoscopic closure of bladder injuries was achieved in all 7 animals with a negative leak test. The site of laceration was successfully identified by the blinded endoscopist and repaired in all 3 animals in which it was attempted. Survival animals had an uneventful postoperative course without any complications.

CONCLUSION

This blinded feasibility study shows that urinary bladder injury occurring during NOTES can be successfully managed via a NOTES approach using currently available endoscopic accessories.

Prostate size is not associated with recovery of sexual function after minimally invasive radical prostatectomy

OBJECTIVES

To investigate the association of prostate weight with recovery of sexual function after minimally invasive radical prostatectomy.

METHODS

Between April 2001 and September 2007, two surgeons performed 856 consecutive laparoscopic radical prostatectomies for clinically localized prostate cancer. Patients were stratified into three groups by prostate weight: <35 g, 35-70 g, and >70 g. Sexual and urinary outcomes were assessed prospectively using the Expanded Prostate Cancer Index Composite (EPIC) questionnaire. Patients who underwent nerve sparing (unilateral or bilateral) with complete preoperative EPIC data, a minimum preoperative Sexual Health Inventory for Men score ≥21, and a minimum of 3 months of complete postoperative EPIC data were included in the analysis.

RESULTS

Of the cohort of 856 men, 324 (38%) had complete, evaluable data and met the inclusion criteria for this study. Preoperatively, there were no significant differences by prostate weight in the EPIC sexual function or bother subscale scores or the proportion of patients participating in sexual intercourse. Postoperatively, we observed statistically similar returns to baseline EPIC sexual function and bother subscale scores and participation in sexual intercourse across all gland weight groups at all time points. EPIC sexual domain scores and the proportions of patients participating in sexual intercourse continued to increase up to 24 months postoperatively, but no group returned to preoperative function at any sampling point.

CONCLUSIONS

Prostate size is not associated with postoperative recovery of sexual function in men undergoing minimally invasive radical prostatectomy.

Impact of surgical technique (open vs laparoscopic vs robotic-assisted) on pathological and biochemical outcomes following radical prostatectomy: an analysis using propensity score matching

OBJECTIVE

• To investigate a single institution experience with radical retropubic prostatectomy (RRP), laparoscopic radical prostatectomy (LRP) and robot-assisted radical prostatectomy (RARP) with respect to pathological and biochemical outcomes.

PATIENTS AND METHODS

• A group of 522 consecutive patients who underwent RARP between 2003 and 2008 were matched by propensity scoring on the basis of patient age, race, preoperative prostate-specific antigen (PSA), biopsy Gleason score and clinical stage with an equal number of patients who underwent LRP and RRP at our institution. • Pathological and biochemical outcomes of the three cohorts were examined.

RESULTS

• Overall positive surgical margin rates were lower among patients who underwent RRP (14.4%) and LRP (13.0%) compared to patients who underwent RARP (19.5%) (P= 0.010). There were no statistically significant differences in positive margin rates between the three surgical techniques for pT2 disease (P= 0.264). • In multivariate logistic regression analysis, surgical technique (P= 0.016), biopsy Gleason score (P < 0.001) and preoperative PSA (P < 0.001) were predictors of positive surgical margins. • Kaplan-Meier analysis did not show any statistically significant differences with respect to biochemical recurrence for the three surgical groups.

CONCLUSIONS

• RRP, LRP and RARP represent effective surgical approaches for the treatment for clinically localized prostate cancer. A higher overall positive SM rate was observed for the RARP group compared to RRP and LRP; however, there was no difference with respect to biochemical recurrence-free survival between groups. • Further prospective studies are warranted to determine whether any particular technique is superior with regard to long-term clinical outcomes.

The learning curve for laparoscopic radical prostatectomy: an international multicenter study

PURPOSE

It is not yet possible to estimate the number of cases required for a beginner to become expert in laparoscopic radical prostatectomy. We estimated the learning curve of laparoscopic radical prostatectomy for positive surgical margins compared to a published learning curve for open radical prostatectomy.

MATERIALS AND METHODS

We reviewed records from 8,544 consecutive patients with prostate cancer treated laparoscopically by 51 surgeons at 14 academic institutions in Europe and the United States. The probability of a positive surgical margin was calculated as a function of surgeon experience with adjustment for pathological stage, Gleason score and prostate specific antigen. A second model incorporated prior experience with open radical prostatectomy and surgeon generation.

RESULTS

Positive surgical margins occurred in 1,862 patients (22%). There was an apparent improvement in surgical margin rates up to a plateau at 200 to 250 surgeries. Changes in margin rates once this plateau was reached were relatively minimal relative to the CIs. The absolute risk difference for 10 vs 250 prior surgeries was 4.8% (95% CI 1.5, 8.5). Neither surgeon generation nor prior open radical prostatectomy experience was statistically significant when added to the model. The rate of decrease in positive surgical margins was more rapid in the open vs laparoscopic learning curve.

CONCLUSIONS

The learning curve for surgical margins after laparoscopic radical prostatectomy plateaus at approximately 200 to 250 cases. Prior open experience and surgeon generation do not improve the margin rate, suggesting that the rate is primarily a function of specifically laparoscopic training and experience.

Toxicity of organic pollutants to seven aquatic organisms: effect of polarity and ionization

The toxicity of organic chemicals to Vibrio fischeri, river bacteria, algae, Daphnia magna and fishes were analysed. The results showed that the toxicity of chemicals to narcotics was dependent on hydrophobicity. A single model for both polar and non-polar narcotics was developed by inclusion of a polarity descriptor as well as the hydrophobic parameter. The highly hydrophobic polar narcotics could be treated as non-polar narcotics because their polar functional group(s) make(s) a relatively small contribution to polarity as compared with their hydrophobicity. In order to investigate the toxic mechanism of action for reactive compounds, the response-surface approach was used to develop models derived from easily calculated descriptors. The stepwise analysis selected the octanol/water partition coefficient and a polarity descriptor to parameterize bio-uptake and reactivity, respectively, for seven species. Benzoic acids can be easily absorbed into the unicellular bacteria, but this is not the case for multicellular D. magna and fish. Their toxicity to V. fischeri is much higher than that to D. magna and carp. Regression analysis was performed based on the model that we developed for ionizable compounds. Good correlations were observed by introducing the correction factor for ionizable compounds. The toxic mechanisms are discussed.

Evaluation of combined toxicity of phenols and lead to Photobacterium phosphoreum and quantitative structure-activity relationships

The combined toxicity of lead (Pb) and nine phenols were measured. The result indicated that the combined toxicity is not only dependent on the Pb concentrations but also on the positions of substituted groups of phenols. Quantitative structure-activity relationship equations were built from the combined toxicity and physico-chemical descriptors of phenols in the different Pb concentrations. The combined toxicity was related to water solubility and the third order molecular connectivity index ((3)X) in low Pb concentration, to solute excess molar refractivity (E) and ionization constant (pKa) in medium Pb concentration and to dipolarity/polarizability (S) in high Pb concentration.

Technical advances in robot-assisted laparoscopic radical prostatectomy

Since it was introduced in 1999, the da Vinci Surgical System has become an integral tool in urologic surgery, specifically in the management of localized prostate cancer. The original technique of robot-assisted laparoscopic prostatectomy (RALP) was developed and standardized in 2000 at the Institut Mutualiste Monsouris. Since that time, the technique of RALP has undergone various modifications. The driving force behind the evolution of the RALP technique in the past decade has been based on efforts to improve upon the three main objectives of surgery, namely the 'trifecta' of cancer cure and the preservation of potency and of urinary continence. In this review, we aim to provide an update on the midterm oncologic outcomes of RALP and focus specifically on two technical modifications that have been introduced in an effort to optimize the outcomes of potency and earlier return of urinary continence.