Intraprostatic Urethra Research Articles

Deep learning-based segmentation of prostatic urethra on computed tomography scans for treatment planning

The intraprostatic urethra is an organ at risk in prostate cancer radiotherapy, but its segmentation in computed tomography (CT) is challenging. This work sought to: i) propose anautomatic pipeline for intraprostatic urethra segmentation in CT, ii) analyze the dose to the urethra, iii) compare the predictions to magnetic resonance (MR) contours. First, we trained Deep Learning networks to segment the rectum, bladder, prostate, and seminal vesicles. Then, the proposed Deep Learning Urethra Segmentation model was trained with the bladder and prostate distance transforms and 44 labeled CT with visible catheters. The evaluation was performed on 11 datasets, calculating centerline distance (CLD) and percentage of centerline within 3.5 and 5mm. We applied this method to a dataset of 32 patients treated with intensity-modulated radiation therapy (IMRT) to quantify the urethral dose. Finally, we compared predicted intraprostatic urethra contours to manual delineations in MR for 15 patients without catheter. A mean CLD of 1.6±0.8mm for the whole urethra and 1.7±1.4, 1.5±0.9, and 1.7±0.9mm for the top, middle, and bottom thirds were obtained in CT. On average, 94% and 97% of the segmented centerlines were within a 3.5mm and 5mm radius, respectively. In IMRT, the urethra received a higher dose than the overall prostate. We also found a slight deviation between the predicted and manual MR delineations. A fully-automatic segmentation pipeline was validated to delineate the intraprostatic urethra in CT images.

Radiation Dose to the Intraprostatic Urethra Correlates Strongly With Urinary Toxicity After Prostate Stereotactic Body Radiation Therapy: A Combined Analysis of 23 Prospective Clinical Trials

Clinical trials assessing evaluation prostate stereotactic body radiation therapy (SBRT) have used a wide range of allowed doses to the intraprostatic urethra, but the relationship between urethral dose and urinary toxicity has not been thoroughly evaluated. The goal of this study was to characterize urinary toxicity outcomes according to urethral dose administered during prostate SBRT. The MEDLINE (PubMed) database was searched for published prospective studies of prostate SBRT through August 2020 that documented a maximum urethral dose metric (MUDM). Reported acute and late urinary toxicity rates were collected. Logistic regression and weighted Pearson correlation models were used to assess associations between urinary toxicity rates and MUDM. Twenty-three unique studies (n=2232 patients) met the inclusion criteria and included a wide range of MUDMs (equivalent dose in 2 Gy fractions [EQD2]: 69-141.75 Gy; α/β=3 Gy). The median follow-up ranged from 3 to 67 months (median, 32 months). On logistic regression analysis, the MUDM EQD2 was significantly associated with multiple urinary toxicity endpoints, including acute grade (G) 2+ (odds ratio [OR], 1.02; P < .001), late G2+ (OR, 1.03; P < .0001), and late G3+ (OR, 1.04; P=.003) urinary toxicity. On weighted Pearson correlation analysis, the MUDM was more closely associated with all evaluated urinary toxicity endpoints than prescription dose, including acute G2+ (r=0.51; P=.02), late G2+ (r=0.9; P < .0001), and late G3+ toxicity (r=0.7; P=.003). Multivariate analysis accounting for age, prostate size, bladder dosimetry, and baseline urinary function confirmed associations between urinary outcomes and MUDM. Within the studied dose range, each increase of 1 Gy to the MUDM corresponded to a 0.8% and 1.0% increase in acute G2+ and late G2+ toxicity, respectively. Radiation dose to the urethra correlates closely with urinary toxicity in patients with prostate cancer treated with SBRT. Attention should be paid to the urethral dose when delivering prostate SBRT to high doses, and approaches for urethral dose reduction warrant further investigation.

Radiation Dose to the Intraprostatic Urethra Correlates Strongly With Urinary Toxicity Following Prostate SBRT: A Combined Analysis of 23 Prospective Clinical Trials

Clinical trials of prostate SBRT have utilized a wide range of allowed doses to the intraprostatic urethra but the relationship between urethral dose and urinary toxicity has not been thoroughly evaluated. We aimed to characterize urinary toxicity outcomes according to urethral dose administered during prostate SBRT.We searched MEDLINE (PubMed) for published prospective studies of prostate SBRT through August 2020 that documented a maximum urethral dose metric (MUDM). Reported acute and late urinary toxicity rates were collected. Weighted correlation and weighted linear regression models were used to assess the associations between urinary toxicity rates and MUDM.Twenty-three unique studies (n = 2232 patients) met the inclusion criteria and included a wide range of MUDMs (EQD2 69 Gy to 141.75 Gy, a/b = 3). Median follow up ranged from 3-67 months (median 32 months). MUDM was strongly associated with urinary toxicity and was more closely associated with toxicity than prescription dose, including acute G2+ (r = 0.51, P = 0.02), late G2+ (r = 0.9, P < 0.0001) and late G3+ toxicity (r = 0.7, P = 0.003). Weighted linear regression accounting for age, prostate size and baseline urinary function confirmed association between urinary outcomes and MUDM. The weighted correlation model predicted late grade 2+ urinary toxicity rates of 2.5%, 5%, 10% and 15% corresponding to MUDMs of 34.2 Gy, 37.7 Gy, 43.9 Gy and 49.4 Gy, respectively, for 5 fraction regimens. Within the studied dose range, each increase of 1 Gy to the MUDM corresponded to a 0.8% and 0.9% increase in acute G2+ and late G2+ toxicity, respectively.Radiation dose to the urethra correlates closely with urinary toxicity in prostate cancer patients treated with SBRT. Attention should be paid to urethral dose when delivering prostate SBRT to high doses and approaches for urethral dose reduction warrant further investigation. These techniques may be facilitated by online adaptive planning with daily urethral delineation.

V08-08 ROBOTIC EXTRAPERITONEAL EXTRAVESICAL PROSTATE ADENOMECTOMY WITH RUNNING SUTURE OF THE BLADDER NECK ONTO THE INTRAPROSTATIC URETHRA

You have accessJournal of UrologyBPH & Bladder Outlet Obstruction (V08)1 Apr 2020V08-08 ROBOTIC EXTRAPERITONEAL EXTRAVESICAL PROSTATE ADENOMECTOMY WITH RUNNING SUTURE OF THE BLADDER NECK ONTO THE INTRAPROSTATIC URETHRA Mustafa Tutal*, Christian Padevit, Beat Foerster, Anja Sauck, Christoph Schregel, Kevin Horton, and Hubert John Mustafa Tutal*Mustafa Tutal* More articles by this author , Christian PadevitChristian Padevit More articles by this author , Beat FoersterBeat Foerster More articles by this author , Anja SauckAnja Sauck More articles by this author , Christoph SchregelChristoph Schregel More articles by this author , Kevin HortonKevin Horton More articles by this author , and Hubert JohnHubert John More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000000909.08AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: Robotic prostate adenomectomy was first reported by Sotelo et al. in transperitoneal and by John et al. in extraperitoneal approach. Meanwhile simple robotic prostatectomies have been modified with transperitoneal or extraperitoneal access using transvesical or extravesical enucleation techniques. We demonstrate our routinely preferred technique with extraperitoneal approach, extravesical prostate adenomectomy and bladder neck reconstruction by running suture of the bladder neck with the intraprostatic urethra. METHODS: Standardized extraperitoneal access is performed with balloon dilatation and placement of a 4-arm daVinci Xi® System under visual control of the instrument tips. The Santorini Plexus is ligated with 3-0 Monocryl to prevent back flow bleeding. The bladder neck is prepared and dissected around the indwelling catheter. Depending on the position of the ureteral orifices, ureteral stents are placed to exclude postoperative ureteral obstruction. The enucleation of the prostate gland is performed with blunt dissection and visually controlled bipolar coagulation of penetrating vessels from the prostate capsule. Preliminary dorsal fixation of the bladder neck to the posterior prostate capsule is performed with 4-0 Stratafix® barbed suture to prevent further tension and additionally minimize capsular bleeding. Thereafter, the urethral tract is reconstructed by direct continuous double armed suture 4-0 Stratafix® according to van Velthoven of the bladder neck with the intraprostatic urethral stump - thereby excluding the prostatic fossa totally. If necessary longitudinal running suture of the ventral bladder neck closes the urinary bladder and patency is tested. The prostate capsule is adapted onto the ventral bladder wall. A suprapubic catheter is placed, the specimen removed and a drain placed between the anterior bladder wall and prostate capsule according to surgeon preference. RESULTS: No irrigation is needed, the indwelling catheter is removed after 24h-48h and the patient discharged after 2-3 days. Cystography excludes urinary leak after 5 days. CONCLUSIONS: This extraperitoneal extravesical robotic adenomectomy provides a minimal invasive procedure in large BPH, thus avoiding significant blood loss, postoperative bleeding, infections and urgencies associated with the enucleated fossa, bladder neck stenosis and urethral injury. The demonstrated operative technique has become our standard after development of our Millin program over 10 years and more than 60 cases. Source of Funding: None © 2020 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 203Issue Supplement 4April 2020Page: e737-e737 Advertisement Copyright & Permissions© 2020 by American Urological Association Education and Research, Inc.MetricsAuthor Information Mustafa Tutal* More articles by this author Christian Padevit More articles by this author Beat Foerster More articles by this author Anja Sauck More articles by this author Christoph Schregel More articles by this author Kevin Horton More articles by this author Hubert John More articles by this author Expand All Advertisement PDF downloadLoading ...

MP42-19 A MULTIPARAMETRIC MAGNETIC RESONANCE IMAGING (MPMRI) PILOT STUDY OF PROSTATIC PERI-URETHRAL FIBROSIS (PUF), A POSSIBLE ALTERNATIVE SOURCE OF LUTS

You have accessJournal of UrologyImaging/Radiology: Uroradiology II (MP42)1 Apr 2020MP42-19 A MULTIPARAMETRIC MAGNETIC RESONANCE IMAGING (MPMRI) PILOT STUDY OF PROSTATIC PERI-URETHRAL FIBROSIS (PUF), A POSSIBLE ALTERNATIVE SOURCE OF LUTS Alexander Kenigsberg*, Ryan Mauck, Alberto Diaz de Leon, Claus Roehrborn, Douglas Strand, and Daniel Costa Alexander Kenigsberg*Alexander Kenigsberg* More articles by this author , Ryan MauckRyan Mauck More articles by this author , Alberto Diaz de LeonAlberto Diaz de Leon More articles by this author , Claus RoehrbornClaus Roehrborn More articles by this author , Douglas StrandDouglas Strand More articles by this author , and Daniel CostaDaniel Costa More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000000891.019AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: We recently described a new fibroblast subtype around the prostatic urethra. Examination of whole mounts from patients undergoing simple prostatectomy revealed that about 20% had PUF. Single cell RNA sequencing and immunostaining revealed that the origin of this fibrosis is the peri-urethral fibroblast, the only collagen-producing prostatic cell type. An emerging hypothesis is that PUF is involved in the pathogenesis of LUTS, particularly in men with smaller glands, but clinical tools are needed. The purpose of this study was to evaluate for the presence of PUF on mpMRI in men for whom whole mount data is not available. METHODS: Men who underwent 3T endorectal coil mpMRI between 2016-2018 for elevated PSA, MRI estimated prostate volume<60cc, and with known AUA symptom score (AUASS) were included. Patients with PIRADS >=2 lesions in the transition zone and prior bladder outlet surgery were excluded. Images were retrospectively interpreted by a radiologist dedicated to prostate MRI, who was aware of suspected prostate cancer (PCa) and blinded to other clinicopathologic findings. High resolution, fast spin-echo axial T2-weighted images part of the mpMRI were assessed for the presence of a PUF tissue (hypointense soft tissue encircling the intraprostatic urethra), its circumferential extent in degrees (0, 25, 50, 75, 100) and the maximum thickness (Figure 1). Univariate analysis and Pearson correlation were used to evaluate relationship between AUASS and PUF. RESULTS: 72 patients met inclusion criteria. PUF was identified in 20/72 (28%) with a mean circumferential extent of 47 degrees and thickness of 2.8 mm. The median AUASS was 7 (mild) and only 2/72 (2.8%) had an AUASS≥20 (severe). There was no difference in AUASS between those with PUF and without (7.8 vs 6.6, p=.48). Circumferential extent, PUF thickness, PSA, and prostate size did not correlate with AUASS. Only age correlated with AUASS (r=.3, p<.01). PCa on biopsy did not predict LUTS (p=.47). CONCLUSIONS: PUF is identified on mpMRI. The correlation of PUF and LUTS remains investigational, as this cohort largely had mild symptoms. Fibrotic processes remain a potential explanation for LUTS in men with smaller glands. Further investigation is necessary to define this relationship and identify these patients. Source of Funding: None © 2020 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 203Issue Supplement 4April 2020Page: e611-e611 Advertisement Copyright & Permissions© 2020 by American Urological Association Education and Research, Inc.MetricsAuthor Information Alexander Kenigsberg* More articles by this author Ryan Mauck More articles by this author Alberto Diaz de Leon More articles by this author Claus Roehrborn More articles by this author Douglas Strand More articles by this author Daniel Costa More articles by this author Expand All Advertisement PDF downloadLoading ...

Radiomics for peripheral zone and intra-prostatic urethra segmentation in MR imaging

Automatic peripheral zone (PZ) and intra-prostatic urethra segmentation has clinical significance in analysis of prostate health management. It is interesting and much challenging task due to heterogeneous and inconsistent pixel intensities around prostate boundary and changes in a shape of the actual prostate capsule from patient to patient. The traditional methods of detection and delineation for glandular prostate gland using magnetic resonance imaging (MRI) involve expertise of radiologists and it is expensive in terms of time and accuracy. This paper proposes a novel technique for automate segmentation of PZ of prostate and intra-prostatic urethra. The technique is based on radiomics extraction using nonnegative matrix factorization (NMF) and segmentation using the self organizing maps (SOMs).The proposed framework is evaluated using 52 axial T2 weighted (T2w) MR images. The dice similarity coefficient (DSC) is calculated to measure the similarity between segmentation results and ground truth images. The proposed algorithm is compared with the conventional K-means (KM) clustering and fuzzy C-means (FCM) clustering approaches of the segmentation. The proposed scheme is shown to be superior based on subjective and objective evaluation analysis. The average percentage of DSC for PZ and intra-prostatic urethra segmentation is 87.33% and 85.55%, respectively using the proposed technique.

Urethra and Ejaculation Preserving Robot-assisted Simple Prostatectomy: Near-infrared Fluorescence Imaging-guided Madigan Technique

BackgroundWith the increasing adoption of novel technologies and anatomical techniques, surgical management of benign prostatic hyperplasia (BPH) provides significant benefits in terms of obstruction relief, early urethral catheter removal, and faster return to daily activities. However, the main pitfall of BPH surgery in sexually active men remains ejaculatory dysfunction (EjD), which permanently affects quality of life. ObjectiveTo detail a novel technique for marking the intraprostatic urethra through a retrograde injection of indocyanine green to enhance selective dissection of prostatic lobes during urethra-sparing robot-assisted simple prostatectomy (US-RASP) with the use of near-infrared fluorescence imaging (NIFI). Design, setting, and participantsBetween January and September 2017, 12 consecutive male patients, who had BPH, were sexually active, and were motivated to preserve ejaculatory function, underwent US-RASP. Surgical procedureUS-RASP with NIFI to enhance the identification and preservation of the prostatic urethra. MeasurementsClinical data were prospectively collected in our institutional RASP dataset. Perioperative and functional outcomes of US-RASP were both graded, and assessed according to Clavien grading system and validated questionnaires postoperatively (International Prostate Symptom Score [IPSS]; Male Sexual Health Questionnaire on EjD [MSHQ-EjD] Short Form) at 3 and 12mo. Results and limitationsMedian preoperative prostate size was 102cc (interquartile range [IQR] 88–115). Median operative time was 150min (IQR 145–170). Median estimated blood loss was 250 (IQR 200–350). Continuous bladder irrigation was avoided in 83.4% of patients. Median time to catheter removal was 7d (IQR 7–7) with a median hospital stay of 3d (IQR 2–3). At 1-yr follow-up, median IPSS score, International Index of Erectile Function score, and MSHQ-EjD Short Form score were 5 (IQR 4–8), 26 (IQR 26–28), and 12 (IQR 1–14), respectively. Satisfactory anterograde ejaculation was reported in eight patients (66%). ConclusionsWe described a novel NIFI-guided technique to perform US-RASP. This technique showed promising early functional results, suggesting a significant role of intraprostatic urethral integrity for the preservation of ejaculatory function. Patient summaryWe developed a novel robotic technique to perform simple prostatectomy with integral preservation of the prostatic urethra. This technique provided a high rate of ejaculatory function preservation.

Multi-atlas-based segmentation of prostatic urethra from planning CT imaging to quantify dose distribution in prostate cancer radiotherapy

Background and purposeSegmentation of intra-prostatic urethra for dose assessment from planning CT may help explaining urinary toxicity in prostate cancer radiotherapy. This work sought to: i) propose an automatic method for urethra segmentation in CT, ii) compare it with previously proposed surrogate models and iii) quantify the dose received by the urethra in patients treated with IMRT. Materials and methodsA weighted multi-atlas-based urethra segmentation method was devised from a training data set of 55 CT scans of patients receiving brachytherapy with visible urinary catheters. Leave-one-out cross validation was performed to quantify the error between the urethra segmentation and the catheter ground truth with two scores: the centerlines distance (CLD) and the percentage of centerline within a certain distance from the catheter (PWR). The segmentation method was then applied to a second test data set of 95 prostate cancer patients having received 78Gy IMRT to quantify dose to the urethra. ResultsMean CLD was 3.25±1.2mm for the whole urethra and 3.7±1.7mm, 2.52±1.5mm, and 3.01±1.7mm for the top, middle, and bottom thirds, respectively. In average, 53% of the segmented centerlines were within a radius<3.5mm from the centerline ground truth and 83% in a radius<5mm. The proposed method outperformed existing surrogate models. In IMRT, urethra DVH was significantly higher than prostate DVH from V74Gy to V79Gy. ConclusionA multi-atlas-based segmentation method was proposed enabling assessment of the dose within the prostatic urethra.

Clinical factors and dosimetry associated with the development of prostate brachytherapy–related urethral strictures: A matched case–control study

PurposeUrethral strictures are a rare complication of prostate brachytherapy (BXT), with prior studies showing radiation dose to the bulbomembranous urethra as being associated with stricture formation. This retrospective case–control study explored clinical and dosimetric parameters associated with the development of BXT-related urethral strictures. Methods and MaterialsA cohort of 34 patients developed urethral strictures after BXT at our institution for the period of 2008–2014. Each case was matched with two controls (68 controls) that had not developed a urethral stricture according to similar baseline clinical and dosimetric parameters. Stricture development was compared with clinical (i.e., age, smoking status, diabetes, hypertension, vascular disease, International Prostate Symptom Score, hormones) and dosimetric (i.e., prostate, urethra, urethral segments [base, midgland, apex, extraprostatic, and 5 mm margin]) variables. Statistical modeling approaches such as univariate, multivariate, and subset selection methods for risk prediction were applied to identify parameter(s) with best predictive ability of toxicity. The performances of models were ranked according to Akaike information criterion score. ResultsThe results show that the R2 statistic increases from 6%, when only one parameter is included in the model, to almost 33%, when all the parameters are included. The best-fit subset of parameters included pretreatment International Prostate Symptom Score sum, urethra D30 Gy, urethra D5 Gy, and intraprostatic urethra with 5-mm margin V200 at the apex having the highest ability to predict the development of urinary strictures. ConclusionsThis study used statistical modeling, a novel approach in prostate BXT dosimetric studies, to identify a subset of parameters with predictive ability in identifying patients who develop urethral strictures.

Patient- and treatment-specific predictors of genitourinary function after high-dose-rate monotherapy for favorable prostate cancer.

High-dose-rate (HDR) brachytherapy alone is an effective treatment option for patients with early-stage prostate cancer. The purpose of this study was to quantify patient-reported short- and long-term toxicity and quality of life (QOL) after HDR monotherapy. Thirty-nine consecutive men between May 2001 and January 2012 were identified for this analysis. All patients underwent definitive HDR monotherapy for favorable prostate cancer to a total dose of 3150 cGy in three fractions, 3800 cGy in four fractions, or 3850 in five fractions. Patient-reported genitourinary function was assessed before HDR, during an acute period after treatment (within 90 days of HDR), and on long-term followup using the American Urological Association International Prostate Symptom Score, a urinary QOL Likert questionnaire, and the Sexual Health Inventory for Men questionnaire. Regression analyses were performed using the ordinary least squares method. With median followup of 57 months, biochemical progression-free survival was 100%. There were no grade ≥3 toxicities. Dose to the urethra and bladder, as well as prostate size and intraprostatic urethra length were predictive for short-term changes in QOL. Advanced patient age was predictive for worse sexual function on both acute and long-term followup. Toxicity after HDR monotherapy for prostate cancer is acceptable. Patients with larger prostates, longer intraprostatic urethras, and greater doses to the bladder and urethra may experience worse acute urinary QOL. Older patients may experience greater impairment in sexual function in the short and long terms.

Urethra low-dose tunnels: Validation of and class solution for generating urethra-sparing dose plans using inverse planning simulated annealing for prostate high-dose-rate brachytherapy

PurposeUrethral dose is related to severity of genitourinary toxicity in patients treated with brachytherapy for prostate cancer. This work describes a dose planning method that uses inverse planning to create a low-dose tunnel around the urethra and presents a class solution to achieve this additional dose sparing of the urethra. MethodsFifteen patients on the Radiation Therapy Oncology Group (RTOG) 0321 protocol were treated for prostate cancer with a high-dose-rate brachytherapy dose boost to an external beam radiation treatment regimen. All were treated with 9.5Gy for each of the two fractions after 45Gy of the external beam radiation. The inverse-planning algorithm, inverse planning simulated annealing (IPSA), was used to create both the standard RTOG protocol (SRP) plan for treatment and the a posteriori urethra dose sparing (UDS) plan consisting of a dose tunnel along the urethra. Both plans maintained the protocol parameters: prostate V100 (volume receiving 100% of prescribed dose)>90% and bladder and rectum V75<1 cm3. In the SRP plans, the urethra surface was optimized to receive <125% of the prescription dose and in the UDS plans <100%. Dose-volume histograms for the clinical treatment volume, bladder, rectum, penile bulb, and urethra for both plans are compared using a paired sample t test with significance claimed for probability values<0.05. ResultsUDS planning reduced the urethra V100 from 88% to 58% on average (p<0.01) and the V125 from 3.3% to 0.2% (p < 0.01). Bladder and rectum V75 were maintained at <1 cm3 and not significantly different between plans. Prostate coverage was maintained per protocol at V100>90%, with mean for the SRP V100=93% versus UDS plan V100=90%. Prostate D90 for SRP was 104% versus UDS plan D90=101%. For all patients, the UDS achieved a dose tunnel surrounding the length of the intraprostatic urethra. The class solution for generating UDS is presented. ConclusionsA urethral sparing–focused planning solution using IPSA reduces mean urethral dose by 34%, as compared with IPSA-generated plans based on the RTOG 0321 protocol. This is done while maintaining prostate coverage and critical structure dose. This technique can be applied to all patients in whom urethra toxicity is of particular concern.

Open MR-Guided High-Dose-Rate (HDR) Prostate Brachytherapy: Feasibility and Initial Experiences Open MR-Guided High-Dose-Rate (HDR) Prostate Brachytherapy

The aim of our pilot study was to demonstrate the feasibility and dosimetric quality of MR-guided HDR prostate brachytherapy in a low-field 0.35T open MRI scanner and to present our initial clinical experiences. 16 patients with intermediate- to high-risk localized prostate cancer were treated with 46-60 Gy of external beam radiotherapy preceded and/or followed by an 8 Gy MR-guided HDR boost. For interventions an MR compatible custom-made system, coaxial needles and plastic catheters were used. Template reconstruction, trajectory planning, image guidance, contouring and treatment planning were exclusively based on MR images. For treatment planning, dose-point- and anatomy-based inverse planning optimization was used. Image quality was found to be good to excellent in almost all cases. The mean catheter placement accuracy modeled by Rayleigh distribution was 2.9 mm with a sigma value of 2.3 mm. The mean and standard deviation (SD) of the dosimetric results for the target volume were the following: V100: 94.2 ± 4.3%, V150: 43.9 ± 6.8%, V200: 18.5 ± 5.9%. The mean D(0.1), D(1) and D1 values for the intraprostatic urethra were 117.6 ± 12.5%, 98.5 ± 19.9% and 122.3 ± 16.4%, respectively. Regarding the rectal wall the mean D(0.1), D(1) and D(2) values were 77.3 ± 7.2%, 64.8 ± 7.5%, and 53.2 ± 9.1%, respectively. The mean maximum dose for the inner rectal surface was 53.5 ± 9.2%. No RTOG Grade 3 or worse acute toxicities were observed. Our method seems to be a promising approach for performing feasible, accurate and high-quality MR-guided HDR prostate brachytherapy. To determine the long term side effects and outcome higher number of patients, additional follow-up is needed.

1941 FULL FUNCTIONAL LENGTH URETHRAL SPHINCTER PRESERVATION DURING OPEN RADICAL PROSTATECTOMY

You have accessJournal of UrologyProstate Cancer: Localized IX1 Apr 20101941 FULL FUNCTIONAL LENGTH URETHRAL SPHINCTER PRESERVATION DURING OPEN RADICAL PROSTATECTOMY Thorsten Schlomm, Oliver Engel, Thomas Steuber, Hans Heinzer, Alexander Haese, Georg Salomon, Hartwig Huland, and Markus Graefen Thorsten SchlommThorsten Schlomm More articles by this author , Oliver EngelOliver Engel More articles by this author , Thomas SteuberThomas Steuber More articles by this author , Hans HeinzerHans Heinzer More articles by this author , Alexander HaeseAlexander Haese More articles by this author , Georg SalomonGeorg Salomon More articles by this author , Hartwig HulandHartwig Huland More articles by this author , and Markus GraefenMarkus Graefen More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2010.02.1930AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES A key prerequisite for urinary continence after radical prostatectomy is the functional length of the urethral sphincter. As demonstrated by functional studies, the intraprostatic urethra between apex and colliculus is an important part of the urethral sphincter complex. Dependence on the apex shape, a significant part of the functional urethra is covered by parenchymal apex tissue. Our modified technique is aimed to preserve the muscular part of the intraprostatic urethra. METHODS We modified our surgical technique by an individualized apical preparation to preserve the full functional length urethra (FFLU). Overall 918 consecutive patients who underwent RRP between May 2008 and July 2009 were analyzed. All surgical procedures were performed by four high volume surgeons. There was no significant difference between the FFLU (n=310) and the non-FFLU (n=608) group with respect to patient age, ASA-status, BMI, preoperative PSA, pT stage, prostatectomy Gleason score, prostate volume, extent of nerve sparing, and preoperative continence. Continence rates were assessed at 7 days and 3 month after removal of the catheter. Multiple logistic regression was used to assess the efficacy of our technical modifications in respect to the continence rates one week after catheter removal. RESULTS The continence rate one week after catheter removal, defined as no pad at all or one protective pad was 79.9% and 72.9% in patients operated with the FFLU technique vs. non-FFLU technique (p=0.017, Pearson chi-square). After 3 month the percentage of continent patients rose to 96.6% and 96.4%, respectively. Early continence results were stratified by age, extent of nerve sparing (non-nervesparing vs. unilateral vs. bilateral approach), BMI, ASA-status, pT-stage, prostatectomy Gleason, preoperative PSA, prostate volume, and surgical technique (FFLU vs. non-FFLU). In multivariate regression analysis, only patient age (p=0.001), ASA-status (p=0.005) and surgical technique (p<0.0001) correlated significantly with the continence status one week after catheter removal. The overall positive surgical margin rates (pT2 and pT3) differed not significantly between the surgical techniques (13.6% vs. 14.9%). CONCLUSIONS The urinary continence results obtained with our modified surgical technique support or concept of an individualized full functional length urethral sphincter preparation. Hamburg, Germany© 2010 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 183Issue 4SApril 2010Page: e754 Peer Review Report Advertisement Copyright & Permissions© 2010 by American Urological Association Education and Research, Inc.MetricsAuthor Information Thorsten Schlomm More articles by this author Oliver Engel More articles by this author Thomas Steuber More articles by this author Hans Heinzer More articles by this author Alexander Haese More articles by this author Georg Salomon More articles by this author Hartwig Huland More articles by this author Markus Graefen More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

212 poster Comparison of dose distribution at the intraprostatic urethra based on interactive dynamic real-time TRUS and CT after permanent seed implantation

212 poster Comparison of dose distribution at the intraprostatic urethra based on interactive dynamic real-time TRUS and CT after permanent seed implantation