New methods for estimating follow-up rates in cohort studies.

BACKGROUND: The follow-up rate, a standard index of the completeness of follow-up, is important for assessing the validity of a cohort study. A common method for estimating the follow-up rate, the "Percentage Method", defined as the fraction of all enrollees who developed the event of interest or had complete follow-up, can severely underestimate the degree of follow-up. Alternatively, the median follow-up time does not indicate the completeness of follow-up, and the reverse Kaplan-Meier based method and Clark's Completeness Index (CCI) also have limitations. METHODS: We propose a new definition for the follow-up rate, the Person-Time Follow-up Rate (PTFR), which is the observed person-time divided by total person-time assuming no dropouts. The PTFR cannot be calculated directly since the event times for dropouts are not observed. Therefore, two estimation methods are proposed: a formal person-time method (FPT) in which the expected total follow-up time is calculated using the event rate estimated from the observed data, and a simplified person-time method (SPT) that avoids estimation of the event rate by assigning full follow-up time to all events. Simulations were conducted to measure the accuracy of each method, and each method was applied to a prostate cancer recurrence study dataset. RESULTS: Simulation results showed that the FPT has the highest accuracy overall. In most situations, the computationally simpler SPT and CCI methods are only slightly biased. When applied to a retrospective cohort study of cancer recurrence, the FPT, CCI and SPT showed substantially greater 5-year follow-up than the Percentage Method (92%, 92% and 93% vs 68%). CONCLUSIONS: The Person-time methods correct a systematic error in the standard Percentage Method for calculating follow-up rates. The easy to use SPT and CCI methods can be used in tandem to obtain an accurate and tight interval for PTFR. However, the FPT is recommended when event rates and dropout rates are high.

Robot-assisted extravesical vesicovaginal fistula repair utilizing laparoscopically mobilized omental flap interposition.

INTRODUCTION AND HYPOTHESIS: High vesicovaginal fistulas (VVF) in the setting of good apical support are best repaired via a transabdominal approach. Laparoscopic VVF repair was first reported in 1998. Several series of robot-assisted VVF repairs have since been published. The robot-assisted approach allows repair of high apical vaginal fistulas while avoiding the morbidity of laparotomy, shortening convalescence, and facilitating the use of omental interposition flaps. This video presents the technique for robot-assisted extravesical VVF repair utilizing a laparoscopically mobilized omental flap. METHODS: A 43-year-old woman developed a VVF after a total abdominal hysterectomy for fibroids. Pre-operative CT urogram and office cystoscopy confirmed the diagnosis and ruled out ureteral involvement. She underwent a robot-assisted extravesical VVF repair utilizing a laparoscopically mobilized omental flap. RESULTS: The surgery was uncomplicated, and the patient was discharged on post-operative day 1. A cystogram 2 weeks post-operatively revealed no evidence of a fistula. At 3 months follow-up, the patient denied any urinary incontinence. CONCLUSIONS: Robot-assisted extravesical VVF repair avoids the morbidity of a laparotomy, provides excellent exposure, and avoids a large cystotomy. It maintains vaginal length and allows for significantly better visualization compared with the transvaginal approach. This repair offers improved outcomes for certain patients depending on their history, anatomy, and the surgeon's experience.

The impact of obesity on prostate cancer recurrence observed after exclusion of diabetics.

PURPOSE: Although overall there is a positive association between obesity and risk of prostate cancer (PrCa) recurrence, results of individual studies are somewhat inconsistent. We investigated whether the failure to exclude diabetics in prior studies could have increased the likelihood of conflicting results. METHODS: A total of 610 PrCa patients who underwent radical prostatectomy between 2005 and 2012 were followed for recurrence, defined as a rise in serum PSA ≥ 0.2 ng/ml following surgery. Body mass index (BMI) and history of type 2 diabetes were documented prior to PrCa surgery. The analysis was conducted using Cox proportional hazard models. RESULTS: Obesity (25.6 %) and diabetes (18.7 %) were common in this cohort. There were 87 (14.3 %) recurrence events during a median follow-up of 30.8 months after surgery among the 610 patients. When analyzed among all PrCa patients, no association was observed between BMI/obesity and PrCa recurrence. However, when analysis was limited to non-diabetics, obese men had a 2.27-fold increased risk (95 % CI 1.17-4.41) of PrCa recurrence relative to normal weight men, after adjusting for age and clinical/pathological tumor characteristics. CONCLUSIONS: This study found a greater than twofold association between obesity/BMI and PrCa recurrence in non-diabetics. We anticipated these results because the relationship between BMI/obesity and the biologic factors that may underlie the PrCa recurrence-BMI/obesity association, such as insulin, may be altered by the use of anti-diabetes medication or diminished beta-cell insulin production in advanced diabetes. Studies to further assess the molecular factors that explain the BMI/obesity-PrCa recurrence relationship are warranted.

Efficacy of robot-assisted radical cystectomy (RARC) in advanced bladder cancer: results from the International Radical Cystectomy Consortium (IRCC).

OBJECTIVE: To characterise the surgical feasibility and outcomes of robot-assisted radical cystectomy (RARC) for pathological T4 bladder cancer. PATIENTS AND METHODS: Retrospective evaluation of a prospectively maintained International Radical Cystectomy Consortium database was conducted for 1118 patients who underwent RARC between 2003 and 2012. We dichotomised patients based on pathological stage (≤pT3 vs pT4) and evaluated demographic, operative and pathological variables in relation to morbidity and mortality. RESULTS: In all, 1000 ≤pT3 and 118 pT4 patients were evaluated. The pT4 patients were older than the ≤pT3 patients (P = 0.001). The median operating time and blood loss were 386 min and 350 mL vs 396 min and 350 mL for p T4 and ≤pT3, respectively. The complication rate was similar (54% vs 58%; P = 0.64) among ≤pT3 and pT4 patients, respectively. The overall 30- and 90-day mortality rate was 0.4% and 1.8% vs 4.2% and 8.5% for ≤pT3 vs pT4 patients (P < 0.001), respectively. The body mass index (BMI), American Society of Anesthesiology score, length of hospital stay (LOS) >10 days, and 90-day readmission were significantly associated with complications in pT4 patients. Meanwhile, BMI, LOS >10 days, grade 3-5 complications, 90-day readmission, smoking, previous abdominal surgery and neoadjuvant chemotherapy were significantly associated with mortality in pT4 patients. On multivariate analysis, BMI was an independent predictor of complications in pT4 patients, but not for mortality. CONCLUSIONS: RARC for pT4 bladder cancer is surgically feasible but entails significant morbidity and mortality. BMI was independent predictor of complications in pT4 patients.

International Robotic Radical Cystectomy Consortium: A way forward.

Robot-assisted radical cystectomy (RARC) is an emerging operative alternative to open surgery for the management of invasive bladder cancer. Studies from single institutions provide limited data due to the small number of patients. In order to better understand the related outcomes, a world-wide consortium was established in 2006 of patients undergoing RARC, called the International Robotic Cystectomy Consortium (IRCC). Thus far, the IRCC has reported its findings on various areas of operative interest and continues to expand its capacity to include other operative modalities and transform it into the International Radical Cystectomy Consortium. This article summarizes the findings of the IRCC and highlights the future direction of the consortium.

Small renal mass: to treat or not to treat.

An increasing number of small renal masses (SRMs) are being detected with modern cross-sectional imaging. The natural history of SRMs is mostly unknown. Initial active surveillance (AS) is a reasonable treatment option for small renal masses (SRMs) < 4 cm in the infirm patient with major comorbidities. Partial nephrectomy (PN) is the established treatment for T1a tumors, provided that the operation is technically feasible and the tumor can be completely removed. Laparoscopic and, most recently, robotic PN have functional and oncologic outcomes comparable to open PN, but are technically demanding procedures. Radical nephrectomy (RN) should be limited to those cases where the tumor is not amenable to PN. Percutaneous needle biopsy of SRMs can be safely performed and has the potential to characterize SRMs histologically. It is best utilized in conjunction with ablative technologies. However, ablative therapies should be reserved for carefully selected patients who are poor surgical candidates.

Detection of prostate cancer in an ethnically diverse, disadvantaged population with multiple prostate specific antigen measurements before biopsy.

PURPOSE: We assessed the predictive effect of prostate specific antigen velocity for men with a minimum of 3 pre-biopsy prostate specific antigen measurements in a racially diverse population. MATERIALS AND METHODS: We identified 795 patients who underwent 3 or more prostate specific antigen tests before prostate biopsy. Prostate specific antigen velocity was calculated by linear regression and used to assess associations with the risk of prostate cancer overall and of high grade prostate cancer (Gleason score 7-10). We created ROC curves and determined the AUC for several models, including only prostate specific antigen velocity or the last prostate specific antigen measurement before biopsy, to predict prostate cancer and high grade prostate cancer. RESULTS: The risk of prostate cancer and high grade prostate cancer increased linearly with increasing prostate specific antigen velocity quartiles (each p trend<0.001). Older patients were more likely to be diagnosed with prostate cancer, given the same prostate specific antigen velocity. In black and Hispanic patients there were strong linear associations between increasing prostate specific antigen velocity and the risk of prostate cancer overall and high grade prostate cancer. ROC curves incorporating prostate specific antigen velocity to predict prostate cancer and high grade prostate cancer varied significantly by race. The AUC of models in black and Hispanic patients was significantly higher than in white patients (0.62 and 0.64, respectively, vs 0.47, p=0.03). CONCLUSIONS: Prostate specific antigen velocity is a significant predictor of prostate cancer and high grade prostate cancer in men with 3 or more prostate specific antigen tests before prostate biopsy. Black and Hispanic patients appear to be at increased risk for prostate cancer at higher prostate specific antigen velocity, as are men older than 60 years. Further studies should confirm these results and create age and race specific guidelines to assess prostate specific antigen velocity.

Assessment of complication and functional outcome reporting in the minimally invasive prostatectomy literature from 2006 to the present.

To query the minimally invasive urological literature from 2006 to the middle of 2010, focusing on complications and functional outcome reporting in laparoscopic radical prostatectomy (LRP) and robot-assisted LRP (RALP), to see if there has been an improvement in the overall reporting of complications. We performed a Medline search using the Medical Subject Heading terms 'prostatectomy', 'laparoscopy', 'robotics', and 'minimally invasive'. We then applied the Martin criteria for complications reporting to the selected articles. We identified 51 studies for a total of 32,680 patients. When excluding functional outcomes the outpatient complications reporting was 20/51 (39.2%). In all, 35% and 43% of papers did not list any method for recording continence and potency, respectively. A complication grading system was only used in 30 studies (58.8%). Of the 16 papers using a grading scale in 2006-2007, only 31.3% used the Clavien system, compared with 69% from 2008 to the first half of 2010. In all, 27% of papers used some form of risk-factor analysis for complications. Multivariate analysis was used in 43% of papers, 29% looked at body mass index, while one looked at prostate weight, and another age. There has been an overall improvement in complications reporting in the minimally invasive RP literature since 2005. However, most studies still do not fulfil many of the criteria necessary for standardised complication reporting. Functional outcome reporting remains poor and unstandardised. Given our current reliance on observational studies, increased efforts should be made to standardise all complication outcomes reporting.

High-risk prostate cancer: the role of radical prostatectomy for local therapy.

The management of high-risk prostate cancer can pose a unique challenge to the urologic oncologist. High-risk prostate cancer remains a real entity, especially in the inner-city urban population centers with high-risk ethnic groups. Although the role of radical prostatectomy is well defined for localized, low-to-intermediate-risk prostate cancer, its role in high-risk disease is more controversial. This is compounded by a lack of a universally accepted definition for 'high-risk' disease and the stage migration that has occurred in prostate cancer in the PSA era, rendering some historical perspectives less relevant. However, what has been accepted is the role of multimodal therapy in the management of this challenging group of patients. This article offers the reader an up-to-date detailed review of this topic, with specific emphasis on the role of radical prostatectomy in this clinical setting, including surgical considerations and outcomes. The advantages in terms of accurate pathologic staging with radical prostatectomy are presented. The role of robotic radical prostatectomy, which is increasingly utilized in the USA for the surgical treatment of prostate cancer in this clinical scenario, is discussed. In addition, we address the shortcomings of adequate clinical staging in this group of patients and discuss advances in imaging that might improve our capabilities in the future.

Current controversies on the role of lymphadenectomy for prostate cancer.

Lymph node dissection is part of the standard treatment protocol for various cancers, but its role in prostate cancer has been debatable for some time. Pelvic lymphadenectomy has been shown to better help stage prostate cancer patients, but has yet to be definitively proven to be of any benefit for survival. Various templates for lymph node dissections exist, and though some national guidelines have endorsed an extended pelvic node dissection, the choice of template is still controversial. Pelvic lymphadenectomy may lead to a slightly higher rate complications and operative time, and their use must be judiciously applied to patients with a high enough risk of lymph node involvement. We present a comprehensive review of the literature regarding the benefits and harms of lymph node dissection in prostate cancer.

Comparison of open and laparoscopic nephrectomy in obese and nonobese patients: outcomes stratified by body mass index.

PURPOSE: Laparoscopic radical nephrectomy has been accepted as the preferred management for low stage renal masses not amenable to partial nephrectomy. Early in the mid 1990s several studies suggested that obesity should be a relative contraindication to laparoscopy. We present our surgical outcomes and complications in patients undergoing open and laparoscopic nephrectomy, stratified by body mass index. MATERIALS AND METHODS: We retrospectively identified 88 patients, of whom 43 underwent open nephrectomy and 45 were treated laparoscopically. All patients were stratified by body mass index to compare multiple perioperative end points and pathological outcomes of laparoscopy. RESULTS: Overall our data showed that compared to open nephrectomy laparoscopic nephrectomy resulted in statistically significant lower estimated blood loss (147.95 vs 640.48 cc, p <0.0002), operative time (156.11 vs 198.95 minutes, p <0.003) and hospital stay (3.7 vs 5.9 days, p <0.004). When stratified by body mass index less than 25, 25 to 29.9 and 30 kg/m(2) or greater, there was a statistically significant difference in estimated blood loss and hospital stay that was in favor of the laparoscopic approach in each body mass index category. Operative time did not show a statistical difference in the subgroups but all laparoscopic procedure times were shorter than open procedure times in each body mass index category. When patients with a body mass index of greater than 30 kg/m(2) were further subgrouped into 35 kg/m(2) or greater and 40 kg/m(2) or greater, there was a statistically significant difference in estimated blood loss and hospital stay that was again in favor of the laparoscopic method. CONCLUSIONS: Laparoscopic radical nephrectomy is technically more challenging as body mass index increases due to many factors but our data show that it is feasible and safe in experienced hands. Laparoscopy appears to result in perioperative outcomes that are superior to those of open nephrectomy in this high risk population with a complication profile that is equivalent to that of the open method for each stratified body mass index category.

Robotic Partial Nephrectomy in Patients with Chronic Kidney Disease: Objective Measurement of Short- and Long-Term Renal Functional Outcomes.

BACKGROUND: Minimal literature informs the use of robotic partial nephrectomy (RPN) in patients with chronic kidney disease (CKD). Therefore, we evaluated the renal functional outcomes in CKD patients undergoing RPN. METHODS: We reviewed a prospective database of patients undergoing RPN 2010 to 2015 and identified 182 patients who had preoperative and postoperative nuclear renal scintigraphy (at 2 and 12 months postop). Preoperative and 12-month postoperative eGFR (mL/min/1.73 m2, by MDRD) were calculated. CKD was defined as eGFR ≤60 mL/min/1.73 m2 (CKD stages III and IV). Changes in creatinine, eGFR, and split function on mercaptoacetyltriglycine (MAG)-3 scan were compared by baseline CKD status. Correlations between pre- and postoperative eGFR were calculated. RESULTS: Of 182 patients, 30 (16.5%) had baseline CKD. Preoperative eGFR was 48.5 and 99.0 in CKD and non-CKD patients, respectively (p < 0.001). From preoperation to 12 months postoperation, eGFR decreased by 2.8 and 1.1 mL/min/1.73 m2, respectively (p = 0.6). On MAG-3 scan, the contribution of the surgical kidney to overall renal function decreased by 5.0% and 4.8% (p = 0.9) in the CKD and non-CKD cohorts, respectively. When comparing renal scans at 2 and 12 months postoperation, in both groups the surgical kidney significantly recovered (both p < 0.001) and the patterns of kidney function recovery was similar in both groups (CKD +2.0%, non-CKD +1.4%, p = 0.6). On long-term follow-up (>2 years), eGFR did not change significantly in either the CKD or non-CKD group (-2.8 vs -1.1 mL/min/1.73 m2, p = 0.6). On pathology, tumors were more frequently malignant in CKD vs non-CKD patients (93.3% vs 73.2%, p = 0.02) and of higher Fuhrman Grade (grade ≥3: 49.7% vs 28.1%, p < 0.001). CONCLUSION: RPN is a reasonable treatment option in patients with CKD, as it did not lead to a greater decline in renal function contributed by the surgical kidney. The patterns of kidney function recovery after surgery are similar between patients with and without CKD.

Incidentally discovered adrenal schwannoma.

Schwannoma is a rare tumor of neural crest cell origin that is rarely seen arising from the adrenal gland. We report a case of an adrenal mass discovered incidentally in a 70-year-old man as part of a hematuria workup. Metabolic evaluation was unremarkable, and imaging studies did not meet strict imaging criteria for a typical adenoma. Following surgical excision and pathologic evaluation with confirmatory immunohistochemical staining, the mass was reported as a benign nerve sheath neoplasm.

Value of Nephrometry Score Constituents on Perioperative Outcomes and Split Renal Function in Patients Undergoing Minimally Invasive Partial Nephrectomy.

OBJECTIVE: To assess the relationship between individual nephrometry score (NS) constituents (RENAL) on perioperative outcomes and renal function of the surgical kidney in patients undergoing laparoscopic partial nephrectomy or robotic-assisted partial nephrectomy. MATERIALS AND METHODS: Two hundred forty-five patients who underwent laparoscopic partial nephrectomy or robotic-assisted partial nephrectomy between 2005 and 2014 were retrospectively reviewed. Each renal mass' NS was calculated from preoperative computed tomography imaging. Multivariate regression analysis was used to evaluate the effect of NS variables on perioperative outcomes and change in overall renal function (as estimated by glomerular filtration rate) from preoperative to 1-year postoperative. A cohort analysis assessed the effect of NS variables on change in split renal function of the surgical kidney from pre- to postoperative based on nuclear medicine renal scintigraphy. RESULTS: Tumor radius (R), endophytic nature (E), and nearness to collecting system (N) variables significantly and incrementally predicted a longer operative time and warm ischemia time. Overall renal function based on glomerular filtration rate was not affected by any NS variable. However, percent function of the surgical kidney by renal scintigraphy significantly decreased postoperatively as R and E values increased. CONCLUSION: R, E, and N were associated with significant changes in warm ischemia time and operative time. R and E were associated with a significant decrease in split renal function of the surgical kidney at 1 year after surgery but not with overall renal function. R, E, and N are the NS constituents most relevant to perioperative outcomes and postoperative differential renal function after partial nephrectomy.