A multicomponent screen for feeding behaviour and nutritional status in Drosophila to interrogate mammalian appetite-related genes.

OBJECTIVE: More than 300 genetic variants have been robustly associated with measures of human adiposity. Highly penetrant mutations causing human obesity do so largely by disrupting satiety pathways in the brain and increasing food intake. Most of the common obesity-predisposing variants are in, or near, genes expressed highly in the brain, but little is known of their function. Exploring the biology of these genes at scale in mammalian systems is challenging. We sought to establish and validate the use of a multicomponent screen for feeding behaviour phenotypes, taking advantage of the tractable model organism Drosophila melanogaster. METHODS: We validated a screen for feeding behaviour in Drosophila by comparing results after disrupting the expression of centrally expressed genes that influence energy balance in flies to those of 10 control genes. We then used this screen to explore the effects of disrupted expression of genes either a) implicated in energy homeostasis through human genome-wide association studies (GWAS) or b) expressed and nutritionally responsive in specific populations of hypothalamic neurons with a known role in feeding/fasting. RESULTS: Using data from the validation study to classify responses, we studied 53 Drosophila orthologues of genes implicated by human GWAS in body mass index and found that 15 significantly influenced feeding behaviour or energy homeostasis in the Drosophila screen. We then studied 50 Drosophila homologues of 47 murine genes reciprocally nutritionally regulated in POMC and agouti-related peptide neurons. Seven of these 50 genes were found by our screen to influence feeding behaviour in flies. CONCLUSION: We demonstrated the utility of Drosophila as a tractable model organism in a high-throughput genetic screen for food intake phenotypes. This simple, cost-efficient strategy is ideal for high-throughput interrogation of genes implicated in feeding behaviour and obesity in mammals and will facilitate the process of reaching a functional understanding of obesity pathogenesis.

Obesity and prostate cancer-specific mortality after radical prostatectomy: results from the Shared Equal Access Regional Cancer Hospital (SEARCH) database.

BACKGROUND: At the population level, obesity is associated with prostate cancer (PC) mortality. However, few studies analyzed the associations between obesity and long-term PC-specific outcomes after initial treatment. METHODS: We conducted a retrospective analysis of 4268 radical prostatectomy patients within the Shared Equal Access Regional Cancer Hospital (SEARCH) database. Cox models accounting for known risk factors were used to examine the associations between body mass index (BMI) and PC-specific mortality (PCSM; primary outcome). Secondary outcomes included biochemical recurrence (BCR) and castration-resistant PC (CRPC). BMI was used as a continuous and categorical variable (normal <25 kg/m2, overweight 25-29.9 kg/m2 and obese ⩾30 kg/m2). Median follow-up among all men who were alive at last follow-up was 6.8 years (interquartile range=3.5-11.0). During this time, 1384 men developed BCR, 117 developed CRPC and 84 died from PC. Hazard ratios were analyzed using competing-risks regression analysis accounting for non-PC death as a competing risk. RESULTS: On crude analysis, higher BMI was not associated with risk of PCSM (P=0.112), BCR (0.259) and CRPC (P=0.277). However, when BMI was categorized, overweight (hazard ratio (HR) 1.99, P=0.034) and obesity (HR 1.97, P=0.048) were significantly associated with PCSM. Obesity and overweight were not associated with BCR or CRPC (all P⩾0.189). On multivariable analysis adjusting for both clinical and pathological features, results were little changed in that obesity (HR=2.05, P=0.039) and overweight (HR=1.88, P=0.061) were associated with higher risk of PCSM, but not with BCR or CRPC (all P⩾0.114) with the exception that the association for overweight was no longer statistical significant. CONCLUSIONS: Overweight and obesity were associated with increased risk of PCSM after radical prostatectomy. If validated in larger studies with longer follow-up, obesity may be established as a potentially modifiable risk factor for PCSM.

Long-term oncological outcomes of apical positive surgical margins at radical prostatectomy in the Shared Equal Access Regional Cancer Hospital cohort.

BACKGROUND: Approximately 29-38% of all positive surgical margins (PSMs) at radical prostatectomy (RP) involve the apex. The prognostic significance of apical PSM remains unclear. We therefore compared the long-term oncologic outcomes of men with apical PSMs to those with negative PSMs, apical and other PSMs, and other PSMs at RP. METHODS: The SEARCH (Shared Equal Access Regional Cancer Hospital) database was used to identify 4031 men with prostate cancer (PCa) managed with RP with complete pathologic grade and stage data. Margin status was categorized as negative, apex only, or other positive. Multivariable Cox regression models adjusted for pathologic stage and grade were developed to test the relationship between margin status and biochemical recurrence (BCR), metastases and PCa death. RESULTS: In the final cohort, 34.3% had PSMs, whereas 65.7% had negative margins. Univariable analysis showed that compared with negative margins, apex-only PSM was associated with BCR (hazard ratio (HR): 1.4 [1.1-1.8]), but not metastases or PCa death, whereas apex and other PSMs were associated with BCR (HR: 3.3 [2.8-4]) and metastases (HR: 1.8 [1.02-3.1]) but not PCa death. Nonapical PSMs were associated with BCR (HR: 2.7 [2.4-3.1]), metastases (1.7 [1.2-2.5)] and PCa death (1.8 [1.05-3]). On multivariable analysis, apex-only, apex and other, and nonapical PSMs were associated with BCR but margin status was not associated with metastases or PCa death. CONCLUSIONS: In a large cohort of men undergoing RP, those with PSMs at the prostatic apex had lower BCR, metastases, or PCa death compared with those with PSMs at other locations. When adjusted for pathologic stage and grade, however, PSMs were associated with BCR but not long-term oncologic outcomes. These data confirm that men with apex-only PSMs may not be ideal candidates for adjuvant therapy after RP.

Do skeletal-related events predict overall survival in men with metastatic castration-resistant prostate cancer?

BACKGROUND: Skeletal-related events (SREs) including pathologic fracture, spinal cord compression, radiation to bone and surgery to bone, are common in men with bone metastatic castration-resistant prostate cancer (mCRPC). Men with mCRPC are at high risk of death. Whether SREs predict mortality is unclear. We tested the association between SREs and overall survival (OS) in a multiethnic cohort with bone mCRPC, controlling for key covariates unavailable in claims data such as bone pain, number of bone metastases and PSA doubling time (PSADT). METHODS: We collected data on 233 men diagnosed with nonmetastatic castration-resistant prostate cancer (CRPC) in 2000-2013 at two Veterans Affairs hospitals who later progressed to bone metastases. First occurrence of SRE and OS were collected from the medical records. Cox models were used to test the association between SRE and OS, treating SRE as a time-dependent variable. We adjusted for age, year, race, treatment center, biopsy Gleason, primary treatment to the prostate, PSA, PSADT, months from androgen deprivation therapy to CRPC, months from CRPC to metastasis and number of bone metastases at initial bone metastasis diagnosis. In a secondary analysis, we also adjusted for bone pain. RESULTS: During follow-up, 88 (38%) patients had an SRE and 198 (85%) died. After adjusting for risk factors, SRE was associated with increased mortality (hazard ratio (HR)=1.67; 95% confidence interval (CI) 1.22-2.30; P=0.001). When bone pain was added to the model, the association of SREs and OS was attenuated, but remained significant (HR=1.42; 95% CI 1.01-1.99; P=0.042). CONCLUSIONS: SREs are associated with increased mortality in men with bone mCRPC. Further studies on the impact of preventing SREs to increase survival are warranted.

In vivo prostate cancer detection and grading using restriction spectrum imaging-MRI.

BACKGROUND: Magnetic resonance imaging (MRI) is emerging as a robust, noninvasive method for detecting and characterizing prostate cancer (PCa), but limitations remain in its ability to distinguish cancerous from non-cancerous tissue. We evaluated the performance of a novel MRI technique, restriction spectrum imaging (RSI-MRI), to quantitatively detect and grade PCa compared with current standard-of-care MRI. METHODS: In a retrospective evaluation of 33 patients with biopsy-proven PCa who underwent RSI-MRI and standard MRI before radical prostatectomy, receiver-operating characteristic (ROC) curves were performed for RSI-MRI and each quantitative MRI term, with area under the ROC curve (AUC) used to compare each term's ability to differentiate between PCa and normal prostate. Spearman rank-order correlations were performed to assess each term's ability to predict PCa grade in the radical prostatectomy specimens. RESULTS: RSI-MRI demonstrated superior differentiation of PCa from normal tissue, with AUC of 0.94 and 0.85 for RSI-MRI and conventional diffusion MRI, respectively (P=0.04). RSI-MRI also demonstrated superior performance in predicting PCa aggressiveness, with Spearman rank-order correlation coefficients of 0.53 (P=0.002) and -0.42 (P=0.01) for RSI-MRI and conventional diffusion MRI, respectively, with tumor grade. CONCLUSIONS: RSI-MRI significantly improves upon current noninvasive PCa imaging and may potentially enhance its diagnosis and characterization.

Predicting bone scan positivity in non-metastatic castration-resistant prostate cancer.

BACKGROUND: To evaluate PSA levels and kinetic cutoffs to predict positive bone scans for men with non-metastatic castration-resistant prostate cancer (CRPC) from the Shared Equal Access Regional Cancer Hospital (SEARCH) cohort. METHODS: Retrospective analysis of 531 bone scans of 312 clinically CRPC patients with no known metastases at baseline treated with a variety of primary treatment types in the SEARCH database. The association of patients' demographics, pathological features, PSA levels and kinetics with risk of a positive scan was tested using generalized estimating equations. RESULTS: A total of 149 (28%) scans were positive. Positive scans were associated with younger age (odds ratio (OR)=0.98; P=0.014), higher Gleason scores (relative to Gleason 2-6, Gleason 3+4: OR=2.03, P=0.035; Gleason 4+3 and 8-10: OR=1.76, P=0.059), higher prescan PSA (OR=2.11; P<0.001), shorter prescan PSA doubling time (PSADT; OR=0.53; P<0.001), higher PSA velocity (OR=1.74; P<0.001) and more remote scan year (OR=0.92; P=0.004). Scan positivity was 6, 14, 29 and 57% for men with PSA<5, 5-14.9, 15-49.9 and ⩾ 50 ng ml(-1), respectively (P-trend <0.001). Men with PSADT ⩾ 15, 9-14.9, 3-8.9 and <3 months had a scan positivity of 11, 22, 34 and 47%, correspondingly (P-trend <0.001). Tables were constructed using PSA and PSADT to predict the likelihood of a positive bone scan. CONCLUSIONS: PSA levels and kinetics were associated with positive bone scans. We developed tables to predict the risk of positive bone scans by PSA and PSADT. Combining PSA levels and kinetics may help select patients with CRPC for bone scans.

Novel technique for characterizing prostate cancer utilizing MRI restriction spectrum imaging: proof of principle and initial clinical experience with extraprostatic extension.

BACKGROUND: Standard magnetic resonance imaging (MRI) of the prostate lacks sensitivity in the diagnosis and staging of prostate cancer (PCa). To improve the operating characteristics of prostate MRI in the detection and characterization of PCa, we developed a novel, enhanced MRI diffusion technique using restriction spectrum imaging (RSI-MRI). METHODS: We compared the efficacy of our novel RSI-MRI technique with standard MRI for detecting extraprostatic extension (EPE) among 28 PCa patients who underwent MRI and RSI-MRI prior to radical prostatectomy, 10 with histologically proven pT3 disease. RSI cellularity maps isolating the restricted isotropic water fraction were reconstructed based on all b-values and then standardized across the sample with z-score maps. Distortion correction of the RSI maps was performed using the alternating phase-encode technique. RESULTS: 27 patients were evaluated, excluding one patient where distortion could not be performed. Preoperative standard MRI correctly identified extraprostatic the extension in two of the nine pT3 (22%) patients, whereas RSI-MRI identified EPE in eight of nine (89%) patients. RSI-MRI correctly identified pT2 disease in the remaining 18 patients. CONCLUSIONS: In this proof of principle study, we conclude that our novel RSI-MRI technology is feasible and shows promise for substantially improving PCa imaging. Further translational studies of prostate RSI-MRI in the diagnosis and staging of PCa are indicated.

Calpain inhibition mediates autophagy-dependent protection against polyglutamine toxicity.

Over recent years, accumulated evidence suggests that autophagy induction is protective in animal models of a number of neurodegenerative diseases. Intense research in the field has elucidated different pathways through which autophagy can be upregulated and it is important to establish how modulation of these pathways impacts upon disease progression in vivo and therefore which, if any, may have further therapeutic relevance. In addition, it is important to understand how alterations in these target pathways may affect normal physiology when constitutively modulated over a long time period, as would be required for treatment of neurodegenerative diseases. Here we evaluate the potential protective effect of downregulation of calpains. We demonstrate, in Drosophila, that calpain knockdown protects against the aggregation and toxicity of proteins, like mutant huntingtin, in an autophagy-dependent fashion. Furthermore, we demonstrate that, overexpression of the calpain inhibitor, calpastatin, increases autophagosome levels and is protective in a mouse model of Huntington's disease, improving motor signs and delaying the onset of tremors. Importantly, long-term inhibition of calpains did not result in any overt deleterious phenotypes in mice. Thus, calpain inhibition, or activation of autophagy pathways downstream of calpains, may be suitable therapeutic targets for diseases like Huntington's disease.

Predicting bone scan positivity after biochemical recurrence following radical prostatectomy in both hormone-naive men and patients receiving androgen-deprivation therapy: results from the SEARCH database.

BACKGROUND: To evaluate the factors associated with positive bone scans after biochemical recurrence (BCR) following radical prostatectomy in both hormone-naive subjects and subjects after androgen-deprivation therapy (ADT). METHODS: Retrospective analysis of 380 bone scans of 301 hormone-naive subjects and 214 bone scans of 137 subjects after ADT following BCR from the Shared Equal Access Regional Cancer Hospital database. Generalized estimating equations and local regression plots were used to evaluate bone scan positivity by patients' demographics, pathological features, PSA levels and kinetics. RESULTS: Among hormone-naive subjects and subjects on ADT, bone scan positivity was seen in 24 (6%) and 65 (30%) subjects, respectively. In hormone-naive subjects, the higher prescan PSA, higher PSA velocity (PSAV) and shorter PSA doubling time (PSADT) were significantly associated with positive scans (P=0.008, P<0.001 and P<0.001, respectively). In subjects after ADT, the prescan PSA, PSAV and PSADT were significantly associated with positive scans (P=0.011, P<0.001 and P=0.002, respectively). Regression plots showed increased scan positivity with increasing PSA levels and shortening PSADT (all P<0.001) for both hormone-naive subjects and subjects after ADT. For a given PSA level and PSADT, subjects on ADT had higher bone scan positivity. CONCLUSIONS: In both hormone-naive subjects and subjects after ADT, more aggressive and advanced disease identified by higher PSA levels, higher PSAV and shorter PSADT were associated with higher bone scan positivity. For the same PSA level and PSADT, subjects after ADT had higher bone scan positivity than hormone-naive subjects. Therefore, PSA levels and kinetics may be used as selection criteria for bone scan in these patients.

Robotic-assisted simple prostatectomy: a systematic review and report of a single institution case series.

Open simple prostatectomy (OSP) is an effective treatment for patients with symptomatic BPH and larger volume prostates; however, it is associated with substantial risks of bleeding, transfusion and prolonged hospital length of stay (LOS). Robotic-assisted simple prostatectomy (RASP) potentially offers improved perioperative outcomes for these patients. We systematically reviewed published data on RASP outcomes and analyzed our experience at the University of California San Diego (UCSD). We identified eight published studies, all non-comparative case series (Level 3 evidence), reporting a total of 109 RASP cases from 2008 to 2012. Indications included acute urinary retention (n=48), persistent obstructive symptoms (n=51), failure of medical management (n=9) and recurrent urinary tract infections (n=2). The mean ages ranged from 65 to 77 years. More than 75% of the studies reported a mean LOS <3 days and a transfusion prevalence of 0%. The mean resected prostate weights ranged from 51 to 301 g. For UCSD, indications for surgery included urinary retention (n=11) and failure of medical management (n=5). The mean age was 68 years, transfusion prevalence 0%, mean resected prostate weight 94 g and mean LOS 1 day. All nine series observed substantial postoperative improvements in urinary symptoms and retention. These data suggest that RASP is a safe and efficacious treatment for BPH in select patients with larger prostates. Although LOS and transfusion prevalence for RASP are markedly lower than the published OSP series, comparative studies are needed to verify these results.

Metformin does not affect risk of biochemical recurrence following radical prostatectomy: results from the SEARCH database.

BACKGROUND: While epidemiologic studies suggest that metformin use among diabetics may decrease prostate cancer (PC) incidence, the effect of metformin use on PC outcome is unclear. We investigated the association between pre-operative metformin use, dose and duration of use and biochemical recurrence (BCR) in PC patients with diabetes who underwent radical prostatectomy (RP). METHODS: We conducted a retrospective cohort analysis within the Shared Equal Access Regional Cancer Hospital (SEARCH) database of 371 PC patients with diabetes who underwent RP. Time to BCR between metformin users and non-users, and by metformin dose and duration of use was assessed using multivariable Cox proportional analysis adjusted for demographic, clinical and/or pathologic features. Time to castrate-resistant PC (CRPC), metastases and PC-specific mortality were explored as secondary outcomes using unadjusted analyses. RESULTS: Of 371 diabetic men, 156 (42%) were using metformin before RP. Metformin use was associated with more recent year of surgery (P<0.0001) but no clinical or pathologic characteristics. After adjustment for year of surgery, clinical and pathologic features, there were no associations between metformin use (hazard ratio (HR) 0.93; 95% confidence interval (CI) 0.61-1.41), high metformin dose (HR 0.96; 95% CI 0.57-1.61) or duration of use (HR 1.00; 95% CI 0.99-1.02) and time to BCR. A total of 14 patients (3.8%) developed CRPC, 10 (2.7%) distant metastases and 8 (2.2%) died from PC. Unadjusted analysis suggested that high metformin dose vs non-use was associated with increased risk of CRPC (HR 5.1; 95% CI 1.6-16.5), metastases (HR 4.8; 95% CI 1.2-18.5) and PC-specific mortality (HR 5.0; 95% CI 1.1-22.5). CONCLUSIONS: Metformin use, dose or duration of use was not associated with BCR in this cohort of diabetic PC patients treated with RP. The suggestion that higher metformin dose was associated with increased risk of CRPC, metastases and PC-specific mortality merits testing in large prospective studies with longer follow-up.

Preoperative weight change and risk of adverse outcome following radical prostatectomy: results from the Shared Equal Access Regional Cancer Hospital database.

BACKGROUND: We examined the relationship between weight change in the year before radical prostatectomy (RP) and biochemical recurrence (BCR) and adverse pathology. METHODS: We abstracted data from 359 men undergoing RP in the SEARCH (Shared Equal Access Regional Cancer Hospital) database between 2001-2007. Logistic regression and Cox proportional hazards models were used to test the association between weight change in the year before surgery and adverse pathology and BCR, respectively. RESULTS: In all, 152 (42%) men gained weight, 193 (54%) lost weight and 14 (4%) had the same weight. Among weight gainers, median gain was 2.4 kg and among weight losers, median loss was 2.7 kg. As a continuous variable, weight change was not associated with adverse pathology or BCR (all P>0.05). In secondary analysis, on multivariate analysis, men gaining ≥ 2.5 kg were at higher BCR risk (hazards ratio=1.65, 95% confidence interval (CI): 1.03-2.64, P=0.04) while weight loss ≥ 2.5 kg was not associated with BCR (hazards ratio=0.83, 95% CI: 0.54-1.29, P=0.41). CONCLUSIONS: As a continuous variable, weight change was not associated with outcome. In secondary hypothesis-generating analyses, weight gain ≥ 2.5 kg in the year before surgery, regardless of final body mass index, was associated with increased BCR following RP. If validated, these data suggest weight gain ≥ 2.5 kg may promote prostate cancer progression.

Target localization and toxicity in dose-escalated prostate radiotherapy with image-guided approach using daily planar kilovoltage imaging.

Dose escalation with intensity-modulated radiation therapy (IMRT) for carcinoma of the prostate has augmented the need for accurate prostate localization prior to dose delivery. Daily planar kilovoltage (kV) imaging is a low-dose image-guidance technique that is prevalent among radiation oncologists. However, clinical outcomes evaluating the benefit of daily kV imaging are lacking. The purpose of this study was to report our clinical experience, including prostate motion and gastrointestinal (GI) and genitourinary (GU) toxicities, using this modality. A retrospective analysis of 100 patients treated consecutively between December 2005 and March 2008 with definitive external beam IMRT for T1c-T4 disease were included in this analysis. Prescription doses ranged from 74-78 Gy (median, 76) in 2 Gy fractions and were delivered following daily prostate localization using on-board kV imaging (OBI) to localize gold seed fiducial markers within the prostate. Acute and late toxicities were graded as per the NCI CTCAEv3.0. The median follow-up was 22 months. The magnitude and direction of prostate displacement and daily shifts in three axes are reported. Of note, 9.1% and 12.9% of prostate displacements were ≥ 5 mm in the anterior-posterior and superior-inferior directions, respectively. Acute grade 2 GI and GU events occurred in 11% and 39% of patients, respectively, however no grade 3 or higher acute GI or GU events were observed. Regarding late toxicity, 2% and 17% of patients developed grade 2 toxicities, and similarly no grade 3 or higher events had occurred by last follow-up. Thus, kV imaging detected a substantial amount of inter-fractional displacement and may help reduce toxicity profiles, especially high grade events, by improving the accuracy of dose delivery.

Robot-assisted laparoscopic radical prostatectomy in men with human immunodeficiency virus.

The aim of this study is to evaluate the outcomes of robot-assisted laparoscopic prostatectomy (RALP) in prostate cancer (PCa) patients with human immunodeficiency virus (HIV). This is a prospective cohort study of HIV patients undergoing RALP, comparing the demographics, tumor characteristics, complications, and short-term oncological outcomes of HIV-positive men to HIV-negative men using univariate (χ(2), Mann-Whitney test) and multivariable (logistic regression) analyses. From 2007 to 2010, 298 men underwent RALP, 8 of whom were known to be HIV positive. Preoperatively, all eight were taking highly active antiretroviral therapy (HAART) and had undetectable viral loads (<50); mean CD4 count was 634 cells per mm(3). HIV-positive men were younger (54 versus 62 years, P=0.010) and less likely to be white (P=0.007). There were no significant differences between groups with respect to clinical staging, pathological and oncological outcomes or most complication rates. However, the prevalence of perioperative transfusions (P=0.031) and ileus (P=0.021) were higher in HIV-positive patients. HIV remained significantly associated with risk of transfusion after adjustment for age, race, Gleason sum and clinical T stage (P=0.002). After a median of 2.6 (range 0.03-19.2) months of follow-up, PSA remained undetectable in all eight HIV patients. These data suggest that RALP is safe for, and demonstrates short-term oncological efficacy in, HIV-positive patients with PCa.

The influence of hepatic function on prostate cancer outcomes after radical prostatectomy.

Prostate growth is dependent on circulating androgens, which can be influenced by hepatic function. Liver disease has been suggested to influence prostate cancer (CaP) incidence. However, the effect of hepatic function on CaP outcomes has not been investigated. A total of 1181 patients who underwent radical prostatectomy (RP) between 1988 and 2008 at four Veterans Affairs hospitals that comprise the Shared Equal Access Regional Cancer Hospital database and had available liver function test (LFT) data were included in the study. Independent associations of LFTs with unfavorable pathological features and biochemical recurrence were determined using logistic and Cox regression analyses. Serum glutamic oxaloacetic transaminase (SGOT) and serum glutamic pyruvic transaminase (SGPT) levels were elevated in 8.2 and 4.4% of patients, respectively. After controlling for CaP features, logistic regression revealed a significant association between SGOT levels and pathological Gleason sum > or =7(4+3) cancer (odds ratio=2.12; 95% confidence interval=1.11-4.05; P=0.02). Mild hepatic dysfunction was significantly associated with adverse CaP grade, but was not significantly associated with other adverse pathological features or biochemical recurrence in a cohort of men undergoing RP. The effect of moderate-to-severe liver disease on disease outcomes in CaP patients managed non-surgically remains to be investigated.

The effect of race on the discriminatory accuracy of models to predict biochemical recurrence after radical prostatectomy: results from the Shared Equal Access Regional Cancer Hospital and Duke Prostate Center databases.

To evaluate whether race modifies the accuracy of nomograms to predict biochemical recurrence (BCR) after radical prostatectomy among subjects from the Shared Equal Access Regional Cancer Hospital (SEARCH) and Duke Prostate Center (DPC) databases. Retrospective analysis of 1721 and 4511 subjects from the SEARCH and DPC cohorts, respectively. The discrimination accuracy for BCR of seven previously published predictive models was assessed using concordance index and compared between African-American men (AAM) and Caucasian men (CM). AAM represented 44% of SEARCH and 14% of DPC. In both cohorts, AAM were more likely to experience BCR than CM (P<0.01). In SEARCH, the mean concordance index across all seven models was lower in AAM (0.678) than CM (0.715), though the mean difference between CM and AAM was modest (0.037; range 0.015-0.062). In DPC the overall mean concordance index for BCR across all seven nomograms was 0.686. In contrast to SEARCH, the mean concordance index in DPC was higher in AAM (0.717) than CM (0.681), though the mean differences between CM and AAM was modest (-0.036; range -0.078 to -0.004). Across all seven models for predicting BCR, the discriminatory accuracy was better among CM in SEARCH and better among AAM in DPC. The mean difference in discriminatory accuracy of all seven nomograms between AAM and CM was approximately 3-4%. This indicates that currently used predictive models have similar performances among CM and AAM. Therefore, nomograms represent a valid and accurate method to predict BCR regardless of race.

Lymph node dissection during robot-assisted radical prostatectomy: where do we stand?

Since the initial report of robot-assisted laparoscopic prostatectomy (RALP) in 2001, the technique has gained rapid acceptance and utilization. When compared with more traditional forms of surgical intervention, there is still much debate with respect to cost, and impact on potency and continence. Less often is the focus on oncologic outcomes. Pelvic lymph node dissection (PLND) at the time of prostatectomy is an important part of the surgical intervention for prostate cancer and is currently underreported during robotic procedures. Herein, we review the current controversies on the value and extent of PLND and the status of emerging data regarding robot-assisted PLND.

Preoperative predictors of blood loss at the time of radical prostatectomy: results from the SEARCH database.

The literature contains conflicting data on preoperative predictors of estimated blood loss (EBL) at radical retropubic prostatectomy (RRP). We sought to examine preoperative predictors of EBL at the time of RRP among patients from the SEARCH database to lend clarity to this issue. A total of 1154 patients were identified in the SEARCH database who underwent RRP between 1988 and 2008 and had EBL data available. We examined multiple preoperative factors for their ability to predict EBL using multivariate linear regression analysis. Median EBL was 900 ml (s.d. 1032). The 25th and 75th percentile for EBL were 600 and 1500 ml, respectively. EBL increased significantly with increasing body mass index (BMI) and increasing prostate size and decreased with more recent year of RRP (all P<0.001). The mean-adjusted EBL in normal-weight men (BMI<25 kg/m(2)) was 807 ml compared to 1067 ml among severely obese men (BM I>or=35 kg/m(2)). Predicted EBL for men with the smallest prostates (<20 g) was 721 ml, compared to 1326 ml for men with prostates >or=100 g. Finally, statistically significant differences between centers were observed, with mean-adjusted EBL ranging from 844 to 1094 ml. Both BMI and prostate size are predictors of increased EBL. Prostate size is of particular note, as a nearly twofold increased EBL was seen from the smallest (<20 g) to the largest prostates (>or=100 g). Over time, average EBL significantly decreased. Finally, significant differences in EBL were observed between centers. Patients with multiple risk factors should be forewarned they are at increased risk for higher EBL, which may translate into a greater need for blood transfusion.

HIV and prostate cancer: a systematic review of the literature.

Malignancy occurs with increased frequency in the HIV-positive population. The true incidence of prostate cancer in this population is unknown. In the few cases that have been presented in the literature, prostate cancer in HIV-positive men appears to behave much like it does in HIV-negative men. Prostate cancer is the most common malignancy in men and the second leading cause of cancer death. Approximately 800,000 men in the United States are HIV positive, and innovative therapies have dramatically improved survival. HIV disproportionately impacts ethnic groups with increased risk of prostate cancer and has been associated with increases in the incidence of certain malignancies. Despite the high prevalence of both diseases, there is relatively little literature about prostate cancer in HIV-positive patients. There is no consensus on how to screen or treat this patient population. We review the literature with regards to incidence, screening, treatment, and outcomes of this poorly characterized population. We briefly discuss the impact of highly active antiretroviral therapy and testosterone supplementation in the development of prostate cancer. A systematic review of the literature was conducted using MEDLINE key words 'HIV,' 'prostate,' 'prostate cancer' and 'AIDS.' Manual bibliographic review of cross-referenced items was also performed. A total of 176 unique abstracts and publications were reviewed; many authors provided data on the incidence of HIV and various malignancies including prostate cancer. Twelve unique publications providing detailed information on 60 patients with HIV and prostate cancer were identified. Prostate cancer is a common malignancy in HIV-positive men. With improved therapies for HIV and increasing survival, the importance for screening and treating prostate cancer is increasing. Acute outcomes of treatment do not demonstrate increased acute morbidity; however long-term outcomes have not been reported.

Impact of nerve sparing on surgical margins and biochemical recurrence: results from the SEARCH database.

The effects of nerve sparing on the risk of positive surgical margins (PSMs) and biochemical recurrence after radical prostatectomy (RP) remain controversial. We examined data from 1018 men treated by RP between 1988 and 2006 at five centers in the Shared Equal Access Regional Cancer Hospital database. Neither bilateral nor unilateral nerve-sparing techniques were associated with a higher risk of PSM; on multivariate analysis of individual sides, the risk of PSM on either side was not increased by nerve sparing on either side. The risk for biochemical recurrence was not affected by bilateral or unilateral nerve sparing. When used on appropriately selected patients, nerve sparing does not increase the probability of PSM or biochemical recurrence after RP.