Predicting contralateral extraprostatic extension in unilateral high-risk prostate cancer: a multicentric external validation study.

PURPOSE: Accurate prediction of extraprostatic extension (EPE) is crucial for decision-making in radical prostatectomy (RP), especially in nerve-sparing strategies. Martini et al. introduced a three-tier algorithm for predicting contralateral EPE in unilateral high-risk prostate cancer (PCa). The aim of the study is to externally validate this model in a multicentric European cohort of patients. METHODS: The data from 208 unilateral high-risk PCa patients diagnosed through magnetic resonance imaging (MRI)-targeted and systematic biopsies, treated with RP between January 2016 and November 2021 at eight referral centers were collected. The evaluation of model performance involved measures such as discrimination (AUC), calibration, and decision-curve analysis (DCA) following TRIPOD guidelines. In addition, a comparison was made with two established multivariable logistic regression models predicting the risk of side specific EPE for assessment purposes. RESULTS: Overall, 38%, 48%, and 14% of patients were categorized as low, intermediate, and high-risk groups according to Martini et al.'s model, respectively. At final pathology, EPE on the contralateral prostatic lobe occurred in 6.3%, 12%, and 34% of patients in the respective risk groups. The algorithm demonstrated acceptable discrimination (AUC 0.68), comparable to other multivariable logistic regression models (p = 0.3), adequate calibration and the highest net benefit in DCA. The limitations include the modest sample size, retrospective design, and lack of central revision. CONCLUSION: Our findings endorse the algorithm's commendable performance, supporting its utility in guiding treatment decisions for unilateral high-risk PCa patients.

Transrectal versus transperineal prostate fusion biopsy: a pair-matched analysis to evaluate accuracy and complications.

PURPOSE: To evaluate biopsy-related complications and detection rates of any PCa and clinically significant PCa (csPCa, intended as grade group ≥ 2) between MRI-targeted TP fusion biopsies (TPBx) and TR ones (TRBx). METHODS: We performed a multicentric study on 4841 patients who underwent fusion biopsy between 2016 and 2023. A case-control matching was performed to find comparable cohorts of 646 TPBx and 646 TRBx. Mean T test and Pearson chi-square tests were used to compare continuous and categorical variables. RESULTS: Baseline characteristics were comparable between the cohorts, except for target location with a higher rate of anterior lesions in TPBx group. Complications were rare and no difference was found between the groups, with similar rates of infections after TRBx and TPBx (N = 5 (0.8%) vs N = 2 (0.3%), p 0.45). All patients in TRBx and 90.1% in TPBx group received antibiotic prophylaxis. A higher csPCa detection rate was found in TPBx over the group (50.5% vs 36.2%, p < 0.001). On average, positive targeted cores were increased in TPBx group, for any PCa (1.6 vs 1.4, p 0.04) and csPCa (1.0 vs 0.8, p 0.02). Among the limitations of study, we acknowledge the retrospective design and the possible under-reporting of complications. CONCLUSIONS: MRI-targeted fusion TPBx achieves a significantly higher csPCa detection than TRBx, with a diagnostic advantage for apical and anterior lesions. No significant differences were found in terms of complications that were rare in both groups, considering a widespread adoption of antibiotic prophylaxis.

The impact of prostate volume estimation on the risk-adapted biopsy decision based on prostate-specific antigen density and magnetic resonance imaging score.

PURPOSE: Utility of prostate-specific antigen density (PSAd) for risk-stratification to avoid unnecessary biopsy remains unclear due to the lack of standardization of prostate volume estimation. We evaluated the impact of ellipsoidal formula using multiparametric magnetic resonance (MRI) and semi-automated segmentation using tridimensional ultrasound (3D-US) on prostate volume and PSAd estimations as well as the distribution of patients in a risk-adapted table of clinically significant prostate cancer (csPCa). METHODS: In a prospectively maintained database of 4841 patients who underwent MRI-targeted and systematic biopsies, 971 met inclusions criteria. Correlation of volume estimation was assessed by Kendall's correlation coefficient and graphically represented by scatter and Bland-Altman plots. Distribution of csPCa was presented using the Schoots risk-adapted table based on PSAd and PI-RADS score. The model was evaluated using discrimination, calibration plots and decision curve analysis (DCA). RESULTS: Median prostate volume estimation using 3D-US was higher compared to MRI (49cc[IQR 37-68] vs 47cc[IQR 35-66], p < 0.001). Significant correlation between imaging modalities was observed (τ = 0.73[CI 0.7-0.75], p < 0.001). Bland-Altman plot emphasizes the differences in prostate volume estimation. Using the Schoots risk-adapted table, a high risk of csPCa was observed in PI-RADS 2 combined with high PSAd, and in all PI-RADS 4-5. The risk of csPCa was proportional to the PSAd for PI-RADS 3 patients. Good accuracy (AUC of 0.69 and 0.68 using 3D-US and MRI, respectively), adequate calibration and a higher net benefit when using 3D-US for probability thresholds above 25% on DCA. CONCLUSIONS: Prostate volume estimation with semi-automated segmentation using 3D-US should be preferred to the ellipsoidal formula (MRI) when evaluating PSAd and the risk of csPCa.

External validation and comparison of magnetic resonance imaging-based risk prediction models for prostate biopsy stratification.

PURPOSE: Magnetic resonance imaging (MRI) is a promising tool for risk assessment, potentially reducing the burden of unnecessary prostate biopsies. Risk prediction models that incorporate MRI data have gained attention, but their external validation and comparison are essential for guiding clinical practice. The aim is to externally validate and compare risk prediction models for the diagnosis of clinically significant prostate cancer (csPCa). METHODS: A cohort of 4606 patients across fifteen European tertiary referral centers were identified from a prospective maintained database between January 2016 and April 2023. Transrectal or transperineal image-fusion MRI-targeted and systematic biopsies for PI-RADS score of ≥ 3 or ≥ 2 depending on patient characteristics and physician preferences. Probabilities for csPCa, defined as International Society of Urological Pathology (ISUP) grade ≥ 2, were calculated for each patients using eight models. Performance was characterized by area under the receiver operating characteristic curve (AUC), calibration, and net benefit. Subgroup analyses were performed across various clinically relevant subgroups. RESULTS: Overall, csPCa was detected in 2154 (47%) patients. The models exhibited satisfactory performance, demonstrating good discrimination (AUC ranging from 0.75 to 0.78, p < 0.001), adequate calibration, and high net benefit. The model described by Alberts showed the highest clinical utility for threshold probabilities between 10 and 20%. Subgroup analyses highlighted variations in models' performance, particularly when stratified according to PSA level, biopsy technique and PI-RADS version. CONCLUSIONS: We report a comprehensive external validation of risk prediction models for csPCa diagnosis in patients who underwent MRI-targeted and systematic biopsies. The model by Alberts demonstrated superior clinical utility and should be favored when determining the need for a prostate biopsy.

Risk stratification for early biochemical recurrence of prostate cancer in the era of multiparametric magnetic resonance imagining-targeted biopsy.

BACKGROUND: Multiparametric magnetic resonance imaging (MRI) and MRI-targeted biopsy are nowadays recommended in the prostate cancer (PCa) diagnostic pathway. Ploussard and Mazzone have integrated these tools into novel risk classification systems predicting the risk of early biochemical recurrence (eBCR) in PCa patients who underwent radical prostatectomy (RP). We aimed to assess available risk classification systems and to define the best-performing. METHODS: Data on 1371 patients diagnosed by MRI-targeted biopsy and treated by RP between 2014 and 2022 at eight European tertiary referral centers were analyzed. Risk classifications systems included were the European Association of Urology (EAU) and National Comprehensive Cancer Network (NCCN) risk groups, the Cancer of the Prostate Risk Assessment (CAPRA) score, the International Staging Collaboration for Cancer of the Prostate (STAR-CAP) classification, the Ploussard and Mazzone models, and ISUP grade group. Kaplan-Meier analyses were used to compare eBCR among risk classification systems. Performance was assessed in terms of discrimination quantified using Harrell's c-index, calibration, and decision curve analysis (DCA). RESULTS: Overall, 152 (11%) patients had eBCR at a median follow-up of 31 months (interquartile range: 19-45). The 3-year eBCR-free survival rate was 91% (95% confidence interval [CI]: 89-93). For each risk classification system, a significant difference among survival probabilities was observed (log-rank test p < 0.05) except for NCCN classification (p = 0.06). The highest discrimination was obtained with the STAR-CAP classification (c-index 66%) compared to CAPRA score (63% vs. 66%, p = 0.2), ISUP grade group (62% vs. 66, p = 0.07), Ploussard (61% vs. 66%, p = 0.003) and Mazzone models (59% vs. 66%, p = 0.02), and EAU (57% vs. 66%, p < 0.001) and NCCN (57% vs. 66%, p < 0.001) risk groups. Risk classification systems demonstrated good calibration characteristics. At DCA, the CAPRA score showed the highest net benefit at a probability threshold of 9%-15%. CONCLUSIONS: The performance of risk classification systems using MRI and MRI-targeted information was less optimistic when tested in a contemporary set of patients. CAPRA score and STAR-CAP classification were the best-performing and should be preferred for treatment decision-making.

A prospective descriptive 1-year study in France of all BCG therapy dispensations for non-muscle-invasive bladder cancer.

OBJECTIVES: To describe the clinico-pathological characteristics of non-muscle-invasive bladder cancer (NMIBC) treated in metropolitan France over 1 year when bacille Calmette-Guérin (BCG) was subject to a national quota, and to document, in the context of recurrent shortages of intravesical BCG for NMIBC, the real-life indications for adjuvant treatment. MATERIALS AND METHODS: Between February 2021 and February 2022, the French National Agency for the Safety of Medicines (ANSM) asked the French Association of Urology to propose a science-based quota solution for BCG using a clinical score. The ANSM then asked the distributor of the drug, MEDAC, to collect the scores for all patients for whom BCG was requested by healthcare institutions and to prioritize the requests for patients with the highest scores. Tumour stage, grade, size, number, time to recurrence, carcinoma in situ, age, accessibility of alternative treatments (total cystectomy, radio-chemotherapy, thermo-chemotherapy) and BCG treatment progress (initiation or maintenance) were documented for each intravesical BCG prescription. A descriptive analysis of the data collected during the quota year was performed. RESULTS: During the 1-year quota, 25 878 requests for BCG were made for 19 024 patients, 60.5% of whom were aged ≥70 years. Requests for induction and maintenance treatment accounted for 12 704 (49.1%) and 13 174 prescriptions (50.9%), respectively. NMIBC treated with BCG maintenance therapy was more frequently high-risk NMIBC (91.7% vs 90.2%; P < 0.0001) than NMIBC for which induction therapy was requested. The number of cases of NMIBC leading to BCG adjuvant treatment was estimated at 12 704 cases/66 062 188 inhabitants over 1 year in metropolitan France. CONCLUSIONS: Our data suggest that the incidence of NMIBC at high risk of recurrence and progression is underestimated in reference epidemiological studies. These results should help to better define future care needs.

Eliciting men's preferences for decision-making relative to treatments of localized prostate cancer with a good or moderate prognosis.

PURPOSE: In diseases where there is no real consensus regarding treatment modalities, promoting shared decision-making can contribute to improving safety and quality of care. This is the case in low- or intermediate-risk localized prostate cancer (PC) treatment. The aim of this study was to investigate the preferences guiding men's decisions regarding the characteristics of the treatment strategies for PC to help physicians adopt a more patient-centered approach. METHODS: This prospective multicenter study used a discrete choice experiment (DCE). The attributes and the modalities were identified from a qualitative study and a literature review. Relative preferences were estimated using a logistic regression model. Interaction terms (demographic, clinical and socio-economic characteristics) were added to the model to assess heterogeneity in preferences. RESULTS: 652 men were enrolled in the study and completed a questionnaire with 12 pairs of hypothetical therapeutic alternatives between which they had to choose. Men's choices were significantly negatively influenced by the risk of impotence and urinary incontinence, death, and the length and frequency of care. They preferred treatments with a rescue possibility in case of deterioration or recurrence and the use of innovative technology. Surprisingly, the possibility of undergoing prostate ablation negatively influenced their choice. The results also highlighted differences in trade-offs according to socio-economic level. CONCLUSION: This study confirmed the importance of considering patients' preferences in the decision-making process. It appears essential to better understand these preferences to allow physicians to improve communication and promote case-by-case decision-making.

Optimizing multiparametric magnetic resonance imaging-targeted biopsy and prostate cancer grading accuracy.

PURPOSE: To assess the most efficient biopsy method to improve International Society of Urological Pathology (ISUP) grade group accuracy with final pathology of the radical prostatectomy (RP) specimen in the era of magnetic resonance imaging (MRI)-driven pathway. METHODS: A total of 753 patients diagnosed by transrectal MRI-targeted and systematic biopsies (namely "standard method"), treated by RP, between 2016 and 2021 were evaluated. Biopsy methods included MRI-targeted biopsy, side-specific systematic biopsies relative to index MRI lesion and combination of both. Number of MRI-targeted biopsy cores and positive cores needed per index MRI lesion were assessed. Multivariable analysis was performed to analyze predictive factors of upgrading using MRI targeted and ipsilateral systematic biopsies method. RESULTS: Overall, ISUP grade group accuracy varied among biopsy methods with upgrading rate of 35%, 49%, 27%, and 24% for MRI targeted, systematic, MRI targeted and ipsilateral systematic biopsies and standard methods, respectively (p < 0.001). A minimum of two positive MRI-targeted biopsies cores per index MRI lesion were required when testing MRI targeted and ipsilateral systematic biopsies method to reach equivalent accuracy compared to standard method. Omitting contralateral systematic biopsies spared an average of 5.9 cores per patient. At multivariable analysis, only the number of positive MRI-targeted biopsy cores per index MRI lesion was predictive of upgrading. CONCLUSION: MRI targeted and ipsilateral systematic biopsies allowed an accurate definition of ISUP grade group and appears to be an interesting alternative when compared with standard method, reducing total number of biopsy cores needed.

Persistent organochlorine pesticides in periprostatic adipose tissue from men with prostate cancer: Ethno-geographic variations, association with disease aggressiveness.

Although several studies have examined the relationship between organochlorine pesticides (OCPs) and prostate cancer (PCa) risk, no data are available concerning the association between OCPs concentrations in periprostatic adipose tissue (PPAT), which reflects cumulative exposure, and PCa aggressiveness. Moreover, no previous study has compared OCPs exposure in two distinct ethno-geographical populations. The objectives were to analyze OCPs in PPAT of PCa patients from either Mainland France or French West Indies in correlation with features of tumor aggressiveness, after adjusting for potential confounders such age, BMI, and polyunsaturated fatty acid (PUFA) content of PPAT. PPAT was analyzed in 160 patients (110 Caucasians and 50 African-Caribbeans), 80 with an indolent tumor (ISUP group 1 + pT2), and 80 with an aggressive tumor (ISUP group more than 3 + pT3). The concentrations of 29 OCPs were measured in PPAT concomitantly with the characterization of PUFA content. Exposure patterns of OCPs differed according to the ethno-geographical origin. Most OCPs were found at higher concentration in Caucasian patients, whereas pp'-DDE content was twice as high in African-Caribbeans. Chlordecone was only detected in PPAT from African-Caribbean patients. Most OCP concentrations were positively correlated with age, and some with BMI. After adjusting for age, BMI, and PUFA composition of PPAT, no significant association was found between OCPs content and risk of aggressive disease, except of mirex which appeared inversely associated with aggressive features of PCa in Caucasian patients. These results highlight a significant ethno-geographic variation in internal exposure to OCPs, which likely reflects differences in consumption patterns. The inverse relationship observed between mirex concentration and markers of PCa aggressiveness need to be further investigated.

Tissue cholesterol metabolism and prostate cancer aggressiveness: Ethno-geographic variations.

BACKGROUND: Prostate cancer (PCa) is more frequent and more aggressive in populations of African descent than in Caucasians. Since the fatty acid composition of peri-prostatic adipose tissue (PPAT) has been shown to differ according to the ethno-geographic origin and is involved in PCa aggressiveness, we aimed to analyze the cholesterol content of PPAT from Caucasian and African-Caribbean patients, in correlation with markers of disease aggressiveness and cholesterol metabolism in cancer tissues. METHODS: The quantification of cholesterol in PPAT was analyzed in 52 Caucasian and 52 African-Caribbean PCa patients, with in each group 26 indolent tumors (ISUP Group1 and pT2) and 26 potentially aggressive tumors (ISUP Group 3-5 and/or pT3). The expression of proteins involved in cholesterol metabolism was analyzed by immunohistochemistry on cancer tissue samples included in tissue microarrays. RESULTS: The amount of cholesterol esters was lower in PPAT from African-Caribbean patients compared with Caucasians, without any correlation with markers of disease aggressiveness. In cancer tissues from African-Caribbean patients, the expression of ABCA1 (involved in cholesterol efflux) was decreased, and that of SREBP-2 (involved in cholesterol uptake) was increased. In both groups of patients, SREBP-2 expression was strongly associated with that of Zeb1, a key player in the epithelial-to-mesenchymal transition (EMT) process. CONCLUSION: These results suggest that cholesterol metabolism differs according to the ethno-geographic origin, in both PPAT and cancer tissues. In African-Caribbeans, the orientation towards accumulation of cholesterol in cancer cells is associated with a more frequent state of EMT, which may promote PCa aggressiveness in this population.

Current Use of the Artificial Urinary Sphincter in Adult Females.

PURPOSE OF REVIEW: The aim of the present report was to review the recent evidences regarding the use of artificial urinary sphincter (AUS) in adult females. RECENT FINDINGS: While the excellent functional outcomes of AUS in female patients with stress urinary incontinence (SUI) due to intrinsic sphincter deficiency (ISD) have been reported for decades, its use has remained confidential in most countries likely due to its challenging implantation and inherent morbidity. Over the past few years, laparoscopic and, more recently, robotic techniques of AUS implantation in female patients have been described with promising perioperative outcomes. As a result, the use of AUS has increased in several countries. The indications are mostly recurrent or persistent SUI after previous anti-incontinence procedures and neurogenic SUI. Owing to its unique potential to restore continence while maintaining low outlet resistance during the voiding phase, AUS may be of special interest in female patients with detrusor underactivity. High level of evidence data from trials which are underway, along with developments in robotic surgery and technological refinements of the device, may well, almost 50 years after its introduction, give to the AUS its momentum as a major contributor in the female SUI armamentarium. While the use of AUS in female patients has been restricted to some countries and a few high-volume centers, it has started spreading again over the past few years, thanks to the rise of minimally invasive approaches which facilitate its implantation, and this is yielding promising outcomes.

Dose to the penile bulb and individual patient anatomy are predictive of erectile dysfunction in men treated with 125I low dose rate brachytherapy for localized prostate cancer.

Background: To evaluate the occurrence of erectile dysfunction at 3 years (3yED) after prostate brachytherapy (BT) and to predict 3yED after treatment based on patients and treatments characteristics. Material and methods: From September 2007 to July 2015, 117 men with mild or no ED [International Index of Erectile Function (IIEF-5) > 16] underwent 125Iodine real-time ultrasound-guided low-dose rate BT to a total dose of 160 Gy for low-risk or favorable intermediate-risk prostate adenocarcinoma, and were followed prospectively during 3 years. Median age was 63 years (51-79). The post-implant dosimetric parameters on the postoperative computer tomography were derived from the dose-volume histogram of the prostate and the penile bulb (PB), crura, neurovascular bundles (NVBs) and internal pudendal arteries (IPAs). Potential clinical confounding factors were collected. Additionally, anatomical indexes reflecting the prostate anatomical location within the pelvis were studied. These variables were compared between patients with and without 3yED. 3yED was defined as an IIEF-5 score change to the lower category between baseline, with or without medication. Results: The 3yED rate was 59% (62% maintained an IIEF-5 > 16). On multivariate analysis, prostate D90% (p > .5) and pretreatment characteristics including age (p > .5), pre-implant potency (p > .5), diabetes (p = .08) and high cardiovascular risk rates (p = .1) did not influence the occurrence of 3yED. Only the PB dose especially the D10% > 51 Gy was associated with 3yED (p = .005). Conversely, dose to the crura, IPAs or NVBs did not seem to impact the erectile function. The prostate position, especially the apex location varied significantly between potent and impotent patients and 3yED was significantly associated with close position of the prostate apex to PB (p = .008). Conclusion: The most predictive factor of 3yED was the dose to the PB. This may be explained by variation in individual patients' anatomy and this could allow for the development of better strategies to prevent ED.

AMS-800 Artificial urinary sphincter in female patients with stress urinary incontinence: A systematic review.

AIMS: To perform a systematic review of studies reporting the outcomes of AMS-800 artificial urinary sphincter (AUS) implantation in female patients with stress urinary incontinence (SUI) resulting from intrinsic sphincter deficiency (ISD). METHODS: A systematic literature search of the Medline and Embase databases was performed in June 2018 in accordance with the PRISMA statement. No time limit was used. The protocol was registered in PROSPERO (CRD42018099612). Study selection and data extraction were performed by two independent reviewers. RESULTS: Of 886 records screened, 17 were included. All were retrospective or prospective non-comparative case series. One study reported on vaginal AUS implantation, 11 on open AUS implantation, two on laparoscopic AUS implantation, two on robot-assisted AUS implantation and one compared open and robot-assisted implantations. The vast majority of patients had undergone at least one anti-incontinence surgical procedure prior to AUS implantation (69.1-100%). The intraoperative bladder neck injury rates ranged from 0% to 43.8% and the intraoperative vaginal injury rates ranged from 0 to 25%. After mean follow-up periods ranging from 5 to 204 months, the complete continence rates ranged from 61.1% to 100%. The rates of explantation, erosion and mechanical failure varied from 0% to 45.3%, 0% to 22.2% and 0% to 44.1%, respectively. CONCLUSIONS: AMS-800 AUS can provide excellent functional outcomes in female patients with SUI resulting from ISD but at the cost of a relatively high morbidity. High level of evidence studies are needed to help better define the role of AUS in the female SUI armamentarium.

Target definition in salvage postoperative radiotherapy for prostate cancer: 18F-fluorocholine PET/CT assessment of local recurrence.

PURPOSE: Inadequate clinical target volume (CTV) definition is likely to be a major contributing factor to local recurrence (LR) rate after radiotherapy. Our aims were to identify sites of prostate cancer LR in biochemical recurrence post-prostatectomy using 18F-Fluorocholine (18F-FCH) positron emission tomography/computed tomography (PET/CT) and to compare different CTV-delineation guidelines in a cohort of postoperative patients. MATERIAL AND METHODS: Thirty-six patients presenting with LR within the prostatic bed on 18F-FCH PET/CT between 10/2011 and 06/2016 were included in this retrospective study. Median PSA at the time of 18F-FCH PET/CT was 2.7 ng/mL (0.8-9.4) and median PSA doubling time was 11 months (3-28). For each patient, the CTVRTOG, CTVFROGG and CTVEORTC following the corresponding guidelines were outlined and compared. Forty-one LR were delineated using a gradient-based method and the percentage of FCH uptake included in each CTV was evaluated. RESULTS: The anastomosis was the most common recurrence site (52.8%), followed by the retrovesical region (31.7%) and the bladder neck (7%). The median SUV max value was 4.8 (2.3-16.1). The percentage of LR entirely included in the CTVRTOG was not significantly different from that included in the CTVFROGG (84% versus 83%, p = .5). Significantly more recurrences were included in the CTVRTOG volume compared to the CTVEORTC (84% versus 68%, p=.006), due to a better coverage of the bladder neck and retrovesical regions. Six out of 10 relapses occurring in the posterior region of the anastomosis were not covered by any of the CTVs. CONCLUSIONS: In our study, the CTVRTOG and CTVFROGG ensured the best coverage of LR seen on 18F-FCH PET/CT. When outlining the prostatic fossa, greater coverage of the posterior vesico-urethral region may allow better coverage of potential microscopic disease.

An analytical model for light backscattering by coccoliths and coccospheres of Emiliania huxleyi.

We present an analytical model for light backscattering by coccoliths and coccolithophores of the marine calcifying phytoplankter Emiliania huxleyi. The model is based on the separation of the effects of diffraction, refraction, and reflection on scattering, a valid assumption for particle sizes typical of coccoliths and coccolithophores. Our model results match closely with results from an exact scattering code that uses complex particle geometry and our model also mimics well abrupt transitions in scattering magnitude. Finally, we apply our model to predict changes in the spectral backscattering coefficient during an Emiliania huxleyi bloom with results that closely match in situ measurements. Because our model captures the key features that control the light backscattering process, it can be generalized to coccoliths and coccolithophores of different morphologies which can be obtained from size-calibrated electron microphotographs. Matlab codes of this model are provided as supplementary material.

Interpretation of scattering by oceanic particles around 120 degrees and its implication in ocean color studies.

Field observations and theoretical studies have found that the volume scattering functions (VSFs) of oceanic particles exhibit minimum variability at angles near 120°. However, its physical interpretation is still unknown. We find this minimum variability angle represents the intersection of two backscattering-normalized VSFs, one representing particles of sizes smaller than the wavelength of light and the other larger than the wavelength of light. This also suggests that the VSFs of oceanic particles at angles between 90° and 180°, which play a critical role in ocean color study, can be modeled by linear mixing of these two end members. We further validate this mixing model using measured VSFs in coastal and oceanic waters around the US and develop a two-component model predicting the backward shapes of the VSFs.

Correlation between prostate volume and single nucleotide polymorphisms implicated in the steroid pathway.

OBJECTIVES: A few preliminary studies have suggested a link between some genetics variants and benign prostatic hyperplasia (BPH). Our goal was to study the link between a set of single nucleotide polymorphisms (SNPs) implicated in the steroid pathway and accurate measurement of prostate volume in a cohort of men who underwent radical prostatectomy. METHODS: Clinical and pathological data including prostate weight were obtained from 611 Caucasian patients with small volume, localized prostate cancer treated by radical prostatectomy. Patients were genotyped for 90 SNPs located inside or nearby genes implicated in the steroid pathway (Sequenom iPLEX). Correlation between prostate weight and genotypes from each SNP was studied by analysis of covariance, adjusted on age and tumor stage. A Bonferroni correction was applied, and the SNPs implicated were then incorporated in a multivariable model. RESULTS AND LIMITATIONS: Seven SNPs located in or nearby genes implicated in steroid hormone metabolism were significantly associated with prostate volume: HSD17B2 (rs1119933), ESR2 (rs8006145), SULT2B1 (rs279451), NQO1 (rs2917670), ESR1 (rs1569788), GSTP1 (rs1138272), and CYP19A1 (rs17523880). Significant association was maintained after multivariate analysis for four SNPs, indicating their independent association with prostate volume. The power of the association of each SNP with prostate volume was comparable to the effect of age. The strongest associations were found with variants in ESR1, ESR2, HSD17B2, and CYP19A1 genes, indicating a potential role of the estrogen signaling pathway in genesis of BPH. CONCLUSIONS: Our results are in favor of an implication of estrogen biotransformation and signaling pathways in the pathophysiology of BPH.

Multicenter international experience of 532 nm-laser photo-vaporization with Greenlight XPS in men with large prostates (prostate volume > 100 cc).

PURPOSE: To evaluate the outcomes and durability of photoselective vaporization of the prostate (PVP) using the XPS-180 system in patients with a large prostate volume (PV) > 100 cc at 4 years of follow-up in a large, multicenter experience. METHODS: 438 men with pre-operative transrectal ultrasound (TRUS) PV > 100 cc were treated in eight experienced centers in Canada, USA, and in France with the Greenlight XPS laser using PVP for the treatment of symptomatic BPH. IPSS, Qmax, postvoid residual (PVR), and prostate-specific antigen (PSA) were measured at 6, 12, 24, 36, and 48 months. Durability was evaluated using BPH retreatment rate at 12, 24, and 36 months. RESULTS: Median PV and PSA were 121 cc and 6.3 ng/dl. Indwelling catheter at the time of surgery was observed in 37% of men. Median operative, laser time, and energy applied were 90 min, 55 min, and 422 kJ, respectively. Median energy delivery was 3.4 kJ/cc of prostate per case. Outpatient surgery was feasible with median length of stay at 24 h. IPSS, Qmax and PVR were significantly improved at all endpoints including at 48 months. Moreover, surgical BPH retreatment rates were 5.4 and 9.3% at 24 and 36 months. Interestingly, characteristics of retreated men include: energy delivery 2.4 vs. 3.4 kJ/cc of prostate (p = 0.02) and PSA reduction at 12 months 26 vs. 51% (p = 0.02). CONCLUSIONS: PVP using Greenlight XPS-180W can potentially provide durable improvements with regard to functional outcomes at 4 years. However, rising retreatment rates after 3 years is of concern. This highlights the imperative need of utilizing a standardized surgical technique (enucleation-like-defect) and an optimal energy density >3KJ/cc.

Inferring inherent optical properties and water constituent profiles from apparent optical properties.

The BP09 experiment conducted by the Centre for Maritime Research and Experimentation in the Ligurian Sea in March 2009 provided paired vertical profiles of nadir-viewing radiances L(u)(z) and downward irradiances E(d)(z) and inherent optical properties (IOPs, absorption, scattering and backscattering coefficients). An inversion algorithm was implemented to retrieve IOPs from apparent optical properties (AOPs, radiance reflectance R(L), irradiance reflectance R(E) and diffuse attenuation coefficient K(d)) derived from the radiometric measurements. Then another inversion algorithm was developed to infer vertical profiles of water constituent concentrations, including chlorophyll-a concentration, non-algal particle concentration, and colored dissolved organic matter from the retrieved IOPs based on a bio-optical model. The algorithm was tested on a synthetic dataset and found to give reliable results with an accuracy better than 1%. When the algorithm was applied to the BP09 dataset it was found that good retrievals of IOPs could be obtained for sufficiently deep waters, i.e. for L(u)(z) and E(d)(z) measurements conducted to depths of 50 m or more. This requirement needs to be satisfied in order to obtain a good estimation of the backscattering coefficient. For such radiometric measurements a correlation of 0.88, 0.96 and 0.93 was found between retrieved and measured absorption, scattering and backscattering coefficients, respectively. A comparison between water constituent values derived from the measured IOPs and in-situ measured values, yielded a correlation of 0.80, 0.78, and 0.73 for chlorophyll-a concentration, non-algal particle concentration, and absorption coefficient of colored dissolved organic matter at 443 nm, respectively. This comparison indicates that adjustments to the bio-optical model are needed in order to obtain a better match between inferred and measured water constituent values in the Ligurian Sea using the methodology developed in this paper.