Risk Factors for the Development of Prostate Brachytherapy Related Urethral Strictures

Management of the Devastated Bladder Outlet after Prostate CANCER Treatment

PURPOSE OF REVIEW

Devastating complications of the bladder outlet resulting from prostate cancer treatments are relatively uncommon. However, the combination of the high incidence of prostate cancer and patient longevity after treatment have raised awareness of adverse outcomes deteriorating patients' quality of life. This narrative review discusses the diagnostic work-up and management options for bladder outlet obstruction resulting from prostate cancer treatments, including those that require urinary diversion.

RECENT FINDINGS

The devastated bladder outlet can be a consequence of the treatment of benign conditions, but more frequently from complications of pelvic cancer treatments. Regardless of etiology, the initial treatment ladder involves endoluminal options such as dilation and direct vision internal urethrotomy, with or without intralesional injection of anti-fibrotic agents. If these conservative strategies fail, surgical reconstruction should be considered. Although surgical reconstruction provides the best prospect of durable success, reconstructive procedures are also associated with serious complications. In the worst circumstances, such as prior radiotherapy, failed reconstruction, devastated bladder outlet with end-stage bladders, or patient's severe comorbidities, reconstruction may neither be realistic nor justified. Urinary diversion with or without cystectomy may be the best option for these patients. Thorough patient counseling before treatment selection is of utmost importance. Outcomes and repercussions on quality of life vary extensively with management options. Meticulous preoperative diagnostic evaluation is paramount in selecting the right treatment strategy for each individual patient. The risk of bladder outlet obstruction, and its severest form, devastated bladder outlet, after treatment of prostate cancer is not negligible, especially following radiation. Management includes endoluminal treatment, open or robot-assisted laparoscopic reconstruction, and urinary diversion in the worst circumstances, with varying success rates.

Health-related Quality of Life in Patients With Urethral Stenosis After Radiation Treatment for Prostate Cancer

OBJECTIVE

To evaluate patient-reported quality of life (PRQoL) in patients presenting with membranous urethral stenosis after prostate radiotherapy. Urethral stenosis is an under-reported complication after prostate radiotherapy with a particular deficiency in PRQoL.

METHODS

Patients presenting with urethral stenosis after radiotherapy were retrospectively reviewed from 2004 to 2022. PRQoL was assessed via patient survey using the Expanded Prostate Cancer Index Composite for Clinical Practice (EPIC-CP).

RESULTS

Two hundred thirty patients were identified at a mean age of 67.7years and mean time to stricture diagnosis of 63.6months' postradiotherapy. Of 87 patients completing the survey, 29.9% recalled being aware of urethral stenosis as a potential complication and 51.7% had documentation of urethral stenosis as a potential complication. 33.5% of patients underwent urethroplasty, 59.6% repeat endoscopic treatment and 6.1% an indwelling catheter. 64.4% of patients reported urinary dysfunction as a "moderate" or "big" problem, 66.7% reported frequent or total incontinence, 64.4% required daily pad use and 50.6% reported incontinence as either a "moderate" or "big" problem. 85.0% reported poor or absent orgasmic dysfunction and 88.5% reported erections insufficient for sexual activity. Additionally, 47.1% of patients reported rectal pain and 31.0% reported dysuria. Depressive symptoms and fatigue were reported by 41.4% and 60.9% of patients respectively.

CONCLUSION

Urethral stenosis after radiotherapy is a clinically complex entity with a broad scope of associated symptoms including high rates of patient-reported incontinence, voiding dysfunction, sexual dysfunction, pain, bowel dysfunction and depression. This multifocal nature combined with often insidious presentation and patient unawareness creates a uniquely challenging condition to treat.

State of the art and future challenges of urethra-sparing stereotactic body radiotherapy for prostate cancer: a systematic review of literature

PURPOSE

Doses delivered to the urethra have been associated with an increased risk to develop long-term urinary toxicity in patients undergoing stereotactic body radiotherapy (SBRT) for prostate cancer (PCa). Aim of the present systematic review is to report on the role of urethra-sparing SBRT (US-SBRT) techniques for prostate cancer, with a focus on outcome and urinary toxicity.

METHOD

A systematic review of the literature was performed on the PubMed database on May 2023. Based on the urethra-sparing technique, 13 studies were selected for the analysis and classified in the two following categories: "urethra-steering" SBRT (restriction of hotspots to the urethra) and "urethra dose-reduction" SBRT (dose reduction to urethra below the prescribed dose).

RESULTS

By limiting the urethra Dmax to 90GyEQD2 (α/β = 3 Gy) with urethra-steering SBRT techniques, late genitourinary (GU) grade 2 toxicity remains mild, ranging between 12.1% and 14%. With dose-reduction strategies decreasing the urethral dose below 70 GyEQD2, the risk of late GU toxicity was further reduced (< 8% at 5 years), while maintaining biochemical relapse-free survival rates up to 93% at 5 years.

CONCLUSION

US-SBRT techniques limiting maximum doses to urethra below a 90GyEQD2 (α/β = 3 Gy) threshold result in a low rate of acute and late grade ≥ 2 GU toxicity. A better understanding of clinical factors and anatomical substructures involved in the development of GU toxicity, as well as the development and use of adapted dose constraints, is expected to further reduce the long-term GU toxicity of prostate cancer patients treated with SBRT.

Long-term follow-up suggests high satisfaction rates for bulbomembranous radiation-induced urethral stenoses treated with anastomotic urethroplasty

PURPOSE

To analyze patients who underwent anastomotic urethroplasty for radiationinduced bulbomembranous urethral stricture/stenosis (RIS) due to prostate cancer treatment with up to 19 years of follow-up and assess long-term patient reported outcomes (PROMs). Long-term follow-up with the inclusion of urethroplasty specific PROMs is lacking in the available research.

METHODS

Patients who underwent anastomotic urethroplasty for RIS were identified from 2002 to 2020. Inclusion criteria included completion of 4-month post-operative cystoscopy and PROMs including IPSS, SHIM, MSHQ-EF, 6Q-LUTS, and global satisfaction queries at 4 months. PROMs were assessed annually thereafter, and cystoscopy was performed for adverse change in PROMs or worsening uroflow/PVR parameters. PROMs were compared at pre-op, post-op, and most recent follow-up.

RESULTS

23 patients met inclusion criteria. Short-term anatomic success was 95.7%. At a mean follow-up of 73.1 months (9.1-228.9), one late recurrence occurred for an overall success of 91.3%. Significant and sustained objective improvement was identified in voiding scores, quality of life, and urethroplasty specific PROMs. Satisfaction was 91.3% despite sexual side effects, and 95.7% of patients stated they would have surgery again knowing their outcome at a mean of over 6 years' follow up.

CONCLUSIONS

RIS are challenging problems, but durable symptomatic relief is achievable in well-selected patients. Patients with bulbomembranous RIS should be appropriately counseled regarding the risk of urinary incontinence and sexual side effects after anastomotic urethroplasty. However, long-term success is high, and overall QoL will have sustained subjective improvement in most cases.

Complications after Prostate Cancer Treatment: Pathophysiology and Repair of Post-Radiation Urethral Stricture Disease

Radiation therapy (RT) in the management of pelvic cancers remains a clinical challenge to urologists given the sequelae of urethral stricture disease secondary to fibrosis and vascular insults. The objective of this review is to understand the physiology of radiation-induced stricture disease and to educate urologists in clinical practice regarding future prospective options clinicians have to deal with this condition. The management of post-radiation urethral stricture consists of conservative, endoscopic, and primary reconstructive options. Endoscopic approaches remain an option, but with limited long-term success. Despite concerns with graft take, reconstructive options such as urethroplasties in this population with buccal grafts have shown long-term success rates ranging from 70 to 100%. Robotic reconstruction is augmenting previous options with faster recovery times. Radiation-induced stricture disease is challenging with multiple interventions available, but with successful outcomes demonstrated in various cohorts including urethroplasties with buccal grafts and robotic reconstruction.

Pelvic radiation-induced urinary strictures: etiology and management of a challenging disease

Radiation is a common treatment modality for pelvic malignancies. While it can be effective at cancer control, downstream effects can manifest months to years after treatment, leaving patients with significant morbidity. Within urology, a particularly difficult post-radiation consequence is urinary tract stricture, either of the urethra, bladder neck, or ureter. In this review, we will discuss the mechanism of radiation damage and treatment options for these potentially devastating urinary sequelae.

MRI-defined treatment margins, urinary toxicity, and PSA response in LDR prostate brachytherapy

PURPOSE

Implant quality metrics as measured by D90 and V100 do not address the adequacy of periprostatic margins. Relative margin deficiencies may relate to efficacy and margin excesses to post-implant toxicity. Our purpose is to determine MRI-defined treatment margins on prostate achieved with LDR brachytherapy.

METHODS AND MATERIALS

Post implant CT and MR images from 487 consecutive patients who received LDR brachytherapy from 2010 to 14 were co-registered. Four prostate quadrants were defined; anterior-superior (AS), posterior-superior (PS), anterior-inferior (AI), posterior-inferior (PI). Dosimetric variables were measured for prostate, and for each quadrant with a 0-, 2-, 3-, and 5-mm margin, as well as for the membranous urethra defined on MRI.

RESULTS

Prostate D90 (no margin) was associated with D90 to the volume enclosed by 2 mm, 3 mm and 5 mm margins (R2 = 0.9 - 1.0) with an average 7.1% decrease in dose per mm of margin. Mean D90 for PS, AI and PI quadrants were > 110% of prescription dose for margins of 2-, 3-, and 5-mm. AS quadrant mean D90s were generally lower (83.2% for 2 mm, 76.4% for 3 mm and 62.2% for 5 mm). Urethral strictures (n = 9) were associated with higher doses in the AI quadrant, and higher membranous urethral V125 (51 vs. 32%, p 0.013) and V150 (34.5 vs. 17.6%, p 0.01).

CONCLUSIONS

Using MR-CT post implant dosimetry, margin coverage up to 5 mm was excellent with less margin coverage in the AS quadrant. Late ≥ grade 2 toxicity and urinary strictures are more likely to occur with relative margin excess in the anterior-inferior quadrant and higher doses caudal to the prostate apex. Within this analysis, there was no relationship between treatment margins, and PSA outcome.

Devastated Bladder Outlet in Pelvic Cancer Survivors: Issues on Surgical Reconstruction and Quality of Life

Bladder outlet obstruction following treatment of pelvic cancer, predominantly prostate cancer, occurs in 1-8% of patients. The high incidence of prostate cancer combined with the long-life expectancy after treatment has increased concerns with cancer survivorship care. However, despite increased oncological cure rates, these adverse events do occur, compromising patients' quality of life. Non-traumatic obstruction of the posterior urethra and bladder neck include membranous and prostatic urethral stenosis and bladder neck stenosis (also known as contracture). The devastated bladder outlet can result from benign conditions, such as neurogenic dysfunction, trauma, iatrogenic causes, or more frequently from complications of oncologic treatment, such as prostate, bladder and rectum. Most posterior urethral stenoses may respond to endoluminal treatments such as dilatation, direct vision internal urethrotomy, and occasionally urethral stents. Although surgical reconstruction offers the best chance of durable success, these reconstructive options are fraught with severe complications and, therefore, are far from being ideal. In patients with prior RT, failed reconstruction, densely fibrotic and/or necrotic and calcified posterior urethra, refractory incontinence or severe comorbidities, reconstruction may not be either feasible or recommended. In these cases, urinary diversion with or without cystectomy is usually required. This review aims to discuss the diagnostic evaluation and treatment options for patients with bladder outlet obstruction with a special emphasis on patients unsuitable for reconstruction of the posterior urethra and requiring urinary diversion.

Current Management of Membranous Urethral Strictures Due to Radiation

Radiotherapy is a frequently used treatment for prostate cancer. It does not only causes the intended damage to cancer cells, but also affects healthy surrounding tissue. As a result radiation-induced urethral strictures occur in 2.2% of prostate cancer patients. Management of urethral strictures is challenging due to the presence of poor vascularized tissue for reconstruction and the proximity of the sphincter, which can impair the functional outcome. This review provides a literature overview of risk factors, diagnostics and management of radiation-induced urethral strictures.

Inverse planning in high-dose rate brachytherapy improves quality of life of prostate cancer patients compared with forward planning

OBJECTIVES

To understand differences in quality of life outcomes between cases with forward planning and cases with inverse planning, we examine patients undergoing high-dose rate brachytherapy combined with external beam radiotherapy for localized prostate cancer.

METHODS

We prospectively identified 283 patients with localized prostate cancer and divided them into forward planning and inverse planning groups. We extracted data on doses to the prostate, rectum and urethra that could potentially affect quality of life. We also evaluated quality of life using the Japanese version of Medical Outcome Study 8-Items Short Form Health Survey and Expanded Prostate Cancer Index Composite at pre-treatment and at 3, 6, 12 and 24 months after treatment. Wilcoxon signed rank test and Bonferroni correction were used to analyze the irradiation dose and any change in quality of life.

RESULTS

Doses to the prostate and rectum were not significantly different between the two groups. Notably, however, doses to the urethra were significantly lower in the inverse planning group than in the forward planning group. Patients in the forward planning group had significantly poorer physical component summary scores at 3 months according to survey results. In Expanded Prostate Cancer Index Composite, patients in the forward planning group had statistically significant poorer urinary, bowel and sexual scores than those in the inverse planning group. Quality of life related to decline in sexual function was significantly reduced in the inverse planning group.

CONCLUSIONS

Inverse planning in high-dose rate brachytherapy could significantly improve quality of life of patients with prostate cancer.

A multi-institutional critical assessment of dorsal onlay urethroplasty for post-radiation urethral stenosis

PURPOSE

To critically evaluate a multi-institutional patient cohort undergoing Dorsal-Onlay Buccal Mucosal Graft Urethroplasty (D-BMGU) for recurrent post-radiation posterior urethral stenosis.

METHODS

Retrospective multi-institutional review of patients with posterior urethral stenosis from 10 institutions between 2010-2019 was performed. Patients with at least 1-year follow-up were assessed. Patient demographics, stenosis characteristics, peri-operative outcomes, and post-operative clinical and patient-reported outcomes were analyzed. The primary outcomes were stenosis recurrence and de-novo stress urinary incontinence (SUI). Secondary outcomes were changes in voiding, sexual function, and patient-reported satisfaction.

RESULTS

Seventy-nine men with post-radiation urethral stenosis treated with D-BMGU met inclusion criteria. Median age and stenosis length were 72 years, (IQR 66-75), and 3.0 cm (IQR 2.5-4 cm), respectively. Radiation modalities included: 36 (45.6%) external beam radiotherapy (EBRT), 13 (16.5%) brachytherapy (BT), 10 (12.7%) combination EBRT/BT, and 20 (25.3%) EBRT/radical prostatectomy. At a median follow-up of 21 months (IQR 13-40), 14 patients (17.7%) had stenosis recurrence. Among 37 preoperatively-continent patients, 3 men (8.1%) developed de-novo SUI following dorsal onlay urethroplasty. Of 29 patients with preoperative SUI all but one remained incontinent post-operatively (96.6%). Following repair, patients experienced significant improvement in PVR (92.5 to 26 cc, p = 0.001) and Uroflow (4.6 to 15.9 cc/s, p = 0.001), and high overall satisfaction, with 91.9% reporting a GRA of + 2 or better).

CONCLUSION

Dorsal onlay buccal mucosa graft urethroplasty is a safe and feasible technique in patients with post-radiation posterior urethral stenosis. This non-transecting approach may confer low rates of de-novo SUI. Further research is needed to compare this technique with excisional urethroplasty.

Canadian Urological Association guideline on male urethral stricture

Urethral stricture is fundamentally a fibrosis of the urethral epithelial and associated corpus spongiosum, which in turn, causes obstruction of the urethral lumen. Patients with urethral stricture most commonly present with lower urinary tract symptoms, urinary retention or urinary tract infection but may also experience a broad spectrum of other signs and symptoms, including genitourinary pain, hematuria, abscess, ejaculatory dysfunction, or renal failure. When urethral stricture is initially suspected based on clinical assessment, cystoscopy is suggested as the modality that most accurately establishes the diagnosis. This recommendation is based on several factors, including the accuracy of cystoscopy, as well as its wide availability, lesser overall cost, and comfort of urologists with this technique. When recurrent urethral stricture is suspected, we suggest performing retrograde urethrography to further stage the length and location of the stricture or referring the patient to a physician with expertise in reconstructive urology. Ultimately, the treatment decision depends on several factors, including the type and acuity of patient symptoms, the presence of complications, prior interventions, and the overall impact of the urethral stricture on the patient's quality of life. Endoscopic treatment, either as dilation or internal urethrotomy, is suggested rather than urethroplasty for the initial treatment of urethral stricture. This recommendation applies to men with undifferentiated urethral stricture and does not apply to trauma-related urethral injuries, penile urethral strictures (hypospadias, lichen sclerosus), or suspected urethral malignancy. In the setting of recurrent urethral stricture, urethroplasty is suggested rather than repeat endoscopic management but this may vary depending on patient preference and impact of the symptoms on the patient.The purpose of this guideline is to provide a practical summary outlining the diagnosis and treatment of urethral stricture in the Canadian setting.

Prognostic Value of Pretreatment MRI in Patients With Prostate Cancer Treated With Radiation Therapy: A Systematic Review and Meta-Analysis

OBJECTIVE. Despite a substantial increase in the use of MRI for pretreatment evaluation of prostate cancer, its prognostic value in patients undergoing radiation therapy (RT) is not well known. Therefore, the purpose of this study was to systematically review the literature and perform a meta-analysis on the prognostic value of pretreatment MRI in patients with prostate cancer who underwent external beam radiation therapy (EBRT) or brachytherapy. MATERIALS AND METHODS. PubMed and Embase databases were searched for studies published on or before March 13, 2019. We included studies that evaluated pretreatment MRI as a prognostic factor in prostate cancer regarding biochemical recurrence (BCR), metastatic failure, and overall or cancer-specific mortality. Effect sizes were measured in terms of the hazard ratio (HR) and were meta-analytically pooled using the random-effects model. The quality of the studies was independently evaluated using the Quality in Prognostic Studies tool. RESULTS. Twelve studies (2205 patients) were included. All studies assessed BCR; metastasis was evaluated in three studies, and mortality was evaluated in one study. Extraprostatic extension (EPE), seminal vesicle invasion (SVI), large tumor size or volume, number of sextants involved, and tumor involvement of prostatic apex were significant prognostic factors of BCR (pooled HRs = 1.50-4.47). EPE, larger tumor size, greater tumor volume, presence of metastatic pelvic lymph nodes (LNs), and presence of SVI were significant risk factors for metastasis (pooled HRs = 1.12-11.96). Pelvic LN metastasis was significantly predictive of cancer-specific mortality (HR = 4.45 [95% CI, 1.30-15.23]). CONCLUSION. Several pretreatment MRI findings were significant prognostic factors in patients with prostate cancer who underwent RT.

Posterior urethral stenosis after prostate cancer treatment: contemporary options for definitive management

Posterior urethral stenosis (PUS) is an uncommon but challenging problem following prostate cancer therapy. A review of the recent literature on the prevalence of PUS and treatment modalities used in the last decade was performed. A summative narrative of current accepted techniques in management of PUS is presented, and supplement with our own experience and algorithms.

Does supplemental external beam radiation therapy impact urinary, bowel, and erectile function following permanent prostate brachytherapy?: results of two prospective randomized trials

Purpose

To evaluate the impact of supplemental external beam radiation therapy (EBRT) prior to permanent prostate brachytherapy on long term urinary, bowel, and erectile function.

Material and methods

Patient administered urinary, bowel, and erectile quality of life (QoL) instrument were obtained prior to treatment and following brachytherapy. The study population was comprised of the 457 patients who were alive as of June 2016, had been randomized to two markedly different supplemental EBRT dose regimens and a third arm without supplemental EBRT, and had completed the June 2016 QoL survey. The need for urinary or bowel surgical intervention was prospectively recorded during routine follow-up. Multiple parameters were evaluated for effect on outcomes.

Results

The urinary catheter was removed on day 0 in 92.1% of patients and 0.4% required a post-implant transurethral prostatic resection (TURP). On average, the International Prostate Symptom Score (IPSS) normalized at week 14. The 10-year rate of urethral strictures was 5.3%. No significant differences were discerned between baseline and post-implant rectal function assessment score (RFAS), and no patient developed a rectal ulcer or fistula. The 10-year potency preservation rate was 50.3%. Supplemental EBRT did not affect urinary, bowel, or erectile function. Urethral strictures were most closely related to bulbomembranous urethral brachytherapy doses, post-implant rectal function to pre-implant hemorroidal bleeding, and RFAS and erectile function to pre-brachytherapy international index of erectile function and age.

Conclusions

Supplemental EBRT did not significantly effect catheter dependency, IPSS resolution, urethral stricture rate, the need for post-implant TURP, bowel, or erectile function. Careful attention to brachytherapy dose distributions appears to be most important in minimizing post-brachytherapy morbidity.

Multisource Rotating Shield Brachytherapy Apparatus for Prostate Cancer

PURPOSE

Our purpose is to present a novel multisource rotating shield brachytherapy (RSBT) apparatus for the simultaneous precise angular and linear positioning of partially shielded ¹⁵³Gd brachytherapy sources in interstitial needles for the treatment of locally advanced prostate cancer. It is designed to lower the dose to nearby healthy tissues, the urethra in particular, relative to conventional high-dose-rate brachytherapy techniques.

METHODS AND MATERIALS

Following needle implantation through the patient template, an angular drive mechanism is docked to the patient template. Each needle is coupled to a multisource afterloader catheter by a connector passing through a shaft. The shafts are rotated about their axes by translating a moving template between 2 stationary templates. The shafts' surfaces and moving template holes are helically threaded with the same pattern such that translation of the moving template causes simultaneous rotation of the shafts. The rotation of each shaft is mechanically transmitted to the catheter-source-shield combination, inside the needles, via several key-keyway pairs. The catheter angles are simultaneously incremented throughout treatment, and only a single 360° rotation of all catheters is needed for a full treatment. For each rotation angle, source depth in each needle is controlled by a multisource afterloader, which is proposed as an array of belt-driven linear actuators, each of which drives a wire that controls catheter depth in a needle.

RESULTS

Treatment plans demonstrated that RSBT with the proposed apparatus reduced urethral D_0.1cm³ (the minimum dose delivered to the hottest 0.1cm³ of the urethra) below that of conventional high-dose-rate brachytherapy by 31% for urethral dose gradient volume within 3 mm of the urethra surface. Treatment time to deliver 20 Gy with the proposed multisource RSBT apparatus by use of nineteen 62.4-GBq ¹⁵³Gd sources was 122 minutes.

CONCLUSIONS

The proposed RSBT delivery apparatus enables a mechanically feasible urethra-sparing treatment technique for prostate cancer in a clinically reasonable time frame.

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

BACKGROUND AND PURPOSE

Segmentation 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 METHODS

A 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.

RESULTS

Mean 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.

CONCLUSION

A multi-atlas-based segmentation method was proposed enabling assessment of the dose within the prostatic urethra.

An update on best practice in the diagnosis and management of post-prostatectomy anastomotic strictures

Postprostatectomy vesicourethral anastomotic stenosis (VUAS) remains a challenging problem for both patient and urologist. Improved surgical techniques and perioperative identification and treatment of risk factors has led to a decline over the last several decades. High-level evidence to guide management is lacking, primarily relying on small retrospective studies and expert opinion. Endourologic therapies, including dilation and transurethral incision or resection with or without adjunct injection of scar modulators is considered first-line management. Recalcitrant VUAS requires surgical reconstruction of the vesicourethral anastomosis, and in poor surgical candidates, a chronic indwelling catheter or urinary diversion may be the only option. This review provides an update in the diagnosis and management of postprostatectomy VUAS.

Management of bladder neck stenosis and urethral stricture and stenosis following treatment for prostate cancer

The aim of this review is to examine all urethral strictures and stenoses subsequent to treatment for prostate cancer, including radical prostatectomy (RP), radiotherapy, high intensity focused ultrasound (HIFU) and cryotherapy. The overall majority respond to endoscopic treatment, including dilatation, direct visual internal urethrotomy (DVIU) or bladder neck incision (BNI). There are adjunct treatments to endoscopic management, including injections of corticosteroids and mitomycin C (MMC) and urethral stents, which remain controversial and are not currently mainstay of treatment. Recalcitrant strictures are most commonly managed with urethroplasty, while recalcitrant stenosis is relatively rare yet almost always associated with bothersome urinary incontinence, requiring bladder neck reconstruction and subsequent artificial urinary sphincter (AUS) implantation, or urinary diversion for the devastated outlet.

[Urethral stricture rate after prostate cancer radiotherapy : Five-year data of a certified prostate cancer center]

BACKGROUND

A urethral stricture is a scar of the urethral epithelium which can cause obstructive voiding dysfunction with consequential damage of the upper urinary tract. Almost 45% of all strictures are iatrogenic; they develop in 2-9% of patients after radical prostatectomy, but can also occur after prostate cancer radiotherapy. This study provides 5‑year data of a certified prostate cancer center (PKZ) in terms of urethral strictures.

MATERIALS AND METHODS

Between 01/2008 and 12/2012 a total of 519 men were irradiated for prostate cancer (LDR and HDR brachytherapy as well as external beam radiation). The entire cohort was followed-up prospectively according to a standardized protocol (by type of irradiation). Short segment urethral strictures were treated by urethrotomy, recurrent and long segment stenosis with buccal mucosa urethroplasty.

RESULTS

A total of 18 of 519 (3.4%) patients developed a urethral stricture post-therapeutically, which recurred in 66% of cases after the first operative treatment. The largest risk for developing a urethral stricture is attributed to the HDR brachytherapy (8.9%).

CONCLUSION

Urethral strictures after prostate cancer radiotherapy should be diagnosed and treated in time for long-term preservation of renal function. The rate of radiogenic urethral strictures (3.4%) is equivalent to those after radical prostatectomy. Due to a high rate of recurrences, urethrotomy has a limited importance after irradiation.

[Pathogenesis of urological complications after radiation therapy]

Radiation therapy is a treatment modality that is often used in the uro-oncological setting. The common indication for the radiation therapy in the urological sphere is prostate cancer, whether it is used primarily as a radical approach, or postoperatively as adjuvant or salvage therapy. All urological organs are sensitive to radiation injury with the urinary bladder being the most susceptible with a typical cascade including acute and late changes, arising in the dose-dependent manner. The common indication for radiation therapy in urology is prostate cancer, which collaterally affects the urinary bladder and rarely urethra (especially the bulbo-membranous urethra). Ureteral damage and stricture formation is almost always restricted to the cases of intraoperative therapy and external beam radiation therapy for other urological malignancies (gynecological organs, rectum, retroperitoneal soft tissue tumors) and should not be underestimated. Postradiotherapeutic tissue changes, especially of the prostate, can cause difficulties for pathologists and urologists with regard to diagnosis of prostate cancer recurrence and salvage therapy.

Urethral strictures after radiation therapy for prostate cancer

Urethral stricture after radiation therapy for localized prostate cancer is a delicate problem as the decreased availability of tissue healing and the close relation to the sphincter complicates any surgical approach. We here review the pathophysiology, dosimetry, and the disease specific aspects of urethral strictures after radiotherapy. Moreover we discuss different treatment option such as direct vision internal urethrotomy as well as techniques for open reconstruction with and without tissue transfer.

Urethral Strictures and Stenoses Caused by Prostate Therapy

The number of patients with prostate cancer and benign prostatic hyperplasia is on the rise. As a result, the volume of prostate treatment and treatment-related complications is also increasing. Urethral strictures and stenoses are relatively common complications that require individualized management based on the length and location of the obstruction, and the patient's overall health, and goals of care. In general, less invasive options such as dilation and urethrotomy are preferred as first-line therapy, followed by more invasive substitution, flap, and anastomotic urethroplasty.

Urethral dose sparing in squamous cell carcinoma of anal canal using proton therapy matching electrons with prior brachytherapy for prostate cancer: A case study

The purpose of this case study is to communicate a technique on treating the re-irradiation of squamous cell carcinoma (SCC) of anal canal with proton fields matched with electron fields to spare prostatic urethra. A 76-year old male presented with a secondary radiation-induced malignancy as a result of prostate brachytherapy seeds irradiation 10 years prior. A rectal examination revealed a bulky tumor at the top of the anal canal involving the left superior-most aspect of the anal canal extending superiorly into the rectum. The inferior extent was palpable approximately 3cm from the anal verge and the superior extent of the mass measured greater than 5cm in the superior-inferior dimension. Chemoradiation was suggested since the patient was opposed to abdominoperineal resection (APR) and colostomy. The use of proton therapy matching with electron fields in the re-irradiation setting could help reduce the complications. A 2 lateral proton beams were designed to treat the bulky tumor volume with 2 electron beams treating the nodal volumes. This complication of treatment fields helped spare the prostatic urethra and reduced the risk of urinary obstruction in the future.

Hemiablative Focal Low Dose Rate Brachytherapy: A Phase II Trial Protocol

BACKGROUND

The objective of focal brachytherapy (BT) is to provide effective prostate cancer control for low-risk disease but with reduced genitourinary, gastrointestinal and sexual side effects in a cost-effective way.

OBJECTIVE

The aim of this study is to describe a phase II study examining technical and dosimetric feasibility and toxicity, quality of life changes, and local control with post-treatment biopsy outcomes in men with early stage low volume prostate cancer treated with focal iodine-125 seed BT.

METHODS

The study design is a prospective, multicenter trial with a planned sample size of 20 patients including men with a minimum age of 60 years, a life expectancy estimated to be greater than 10 years, with low or low-tier intermediate risk prostate cancer, unilateral disease on the biopsy, and a Gleason score of ≤3+4 and <25% cores involved. The investigations specific for the study are multi-parametric magnetic resonance imaging (Mp-MRI) baseline, at 20 and 36 months to rule out high grade disease and a transperineal mapping biopsy (baseline and at 36 months) for more accurate patient selection. The hemigland region will receive 144 Gy. Standard normal tissue constraints will be considered as for a whole gland (WG) implant. Dosimetric parameters will be evaluated at day 30 after the implant. Toxicity and quality of life will be evaluated with international validated questionnaires focusing on urinary, rectal, sexual domain, and general health-related quality of life. The patients will complete this assessment at baseline and then approximately every 6 months after the implant up to 10 years.

RESULTS

To date, one patient is involved in the trial. He underwent the pre-implant investigations which found bilateral disease. Therefore, a standard seed implant was performed. If the results from this trial provide evidence that the treatment is safe, feasible, and improves toxicity, funding will be sought to conduct a large, multicenter, randomized controlled trial (RCT).

CONCLUSIONS

This protocol is designed to show feasibility in delivering hemigland focal therapy with seed BT. It may answer crucial questions and obtain data which will enable downstream decisions on focal low dose rate (LDR) prostate BT.

CLINICALTRIAL

Clinicaltrial.gov NCT02643511; https://www.clinicaltrials.gov/ct2/show/NCT02643511 (Archived by Webcite at http://www.webcitation.org/6ghLCzIhY).

Urethroplasty in radiation-induced strictures

PURPOSE OF REVIEW

In patients presenting with urethral stricture disease, the mainstay of definitive treatment is urethroplasty. Until recently, it was unclear if urethroplasty was a feasible option in patients with urethral stricture secondary to pelvic radiation exposure. We review the feasibility and outcomes for urethroplasty in patients with radiation-induced urethral stricture.

RECENT FINDINGS

Urethroplasty in patients exposed to radiation can be technically challenging secondary to stricture location and tissue damage; however, it still has an acceptable success rate with durable outcomes. Most radiation-induced strictures are limited in length, located in the bulbomembranous region, and are amenable to excision and primary anastomosis. There are higher rates of postoperative urinary incontinence in this cohort when compared with outcomes for urethroplasty without radiation exposure; however, erectile function appears to be preserved.

SUMMARY

Recent studies highlight that urethroplasty has acceptable success rates in men with radiation-induced urethral stricture. Patients in this cohort need to be counseled on the potential for urinary incontinence following urethroplasty.

Predictive factors for urinary toxicity after iodine-125 prostate brachytherapy with or without supplemental external beam radiotherapy

PURPOSE

We examined the factors associated with urinary toxicities because of brachytherapy with iodine-125 with or without supplemental external beam radiotherapy (EBRT) for prostate cancer.

METHODS AND MATERIALS

We investigated 1313 patients with localized prostate cancer treated with iodine-125 brachytherapy with or without supplemental EBRT between 2003 and 2009. The International Prostate Symptom Score (IPSS) and Common Terminology Criteria for Adverse Events data were prospectively determined. Patients, treatment, and implant factors were investigated for their association with urinary toxicity or symptoms.

RESULTS

IPSS resolution was not associated with biologically effective dose (BED). Baseline IPSS, total needles, and the minimal dose received by 30% of the urethra had the greatest effect according to multivariate analysis (MVA). Urinary symptom flare was associated with baseline IPSS, age, BED, and EBRT on MVA. Urinary symptom flare and urinary Grade 2 or higher (G2+) toxicity occurred in 51%, 58%, and 67% (p = 0.025) and 16%, 22%, and 20% (p = 0.497) of the <180, 180-220, and >220 Gy BED groups, respectively. Urinary G2+ toxicity was associated with baseline IPSS, neoadjuvant androgen deprivation therapy (NADT), and seed density on MVA. When we divided patients into four groups according to prostate volume (<30 cc or ≥30 cc) and NADT use, urinary G2+ toxicity was most commonly observed in those patients with larger prostates who received NADT, and least in the patients with smaller prostates and no NADT.

CONCLUSIONS

NADT was associated with urinary G2+ toxicity. Higher dose and supplemental EBRT did not appear to increase moderate to severe urinary toxicities or time to IPSS resolution; however, it influenced urinary symptom flare.

Obstructive urination problems after high-dose-rate brachytherapy boost treatment for prostate cancer are avoidable

Background

Aiming at improving treatment individualization in patients with prostate cancer treated with combination of external beam radiotherapy and high-dose-rate brachytherapy to boost the dose to prostate (HDRB-B), the objective was to evaluate factors that have potential impact on obstructive urination problems (OUP) after HDRB-B.

Patients and methods

In the follow-up study 88 patients consecutively treated with HDRB-B at the Institute of Oncology Ljubljana in the period 2006-2011 were included. The observed outcome was deterioration of OUP (DOUP) during the follow-up period longer than 1 year. Univariate and multivariate relationship analysis between DOUP and potential risk factors (treatment factors, patients’ characteristics) was carried out by using binary logistic regression. ROC curve was constructed on predicted values and the area under the curve (AUC) calculated to assess the performance of the multivariate model.

Results

Analysis was carried out on 71 patients who completed 3 years of follow-up. DOUP was noted in 13/71 (18.3%) of them. The results of multivariate analysis showed statistically significant relationship between DOUP and anti-coagulation treatment (OR 4.86, 95% C.I. limits: 1.21-19.61, p = 0.026). Also minimal dose received by 90% of the urethra volume was close to statistical significance (OR = 1.23; 95% C.I. limits: 0.98-1.07, p = 0.099). The value of AUC was 0.755.

Conclusions

The study emphasized the relationship between DOUP and anticoagulation treatment, and suggested the multivariate model with fair predictive performance. This model potentially enables a reduction of DOUP after HDRB-B. It supports the belief that further research should be focused on urethral sphincter as a critical structure for OUP.

Observations and outcomes of urethroplasty for bulbomembranous stenosis after radiation therapy for prostate cancer

PURPOSE

Bulbomembranous stenosis is a significant complication of radiotherapy for prostate cancer. Our purpose is to report outcomes of urethroplasty for radiation-induced bulbomembranous urethral stenoses.

METHODS

Thirty-five patients underwent urethroplasty for refractory radiation-induced bulbomembranous stenoses from January 2004 to November 2013. Patients had a minimum follow-up of 12 months with routine cystoscopy at 6 and 12 months. Primary outcome was urethral patency, and secondary outcomes were 90-day complications, de novo incontinence, de novo erectile dysfunction and bothersome LUTS. Outcomes were compared using Fisher's exact test.

RESULTS

Of the 35 patients, 20 and 15 had stenosis related to external beam radiation therapy and brachytherapy, respectively. Mean stricture length was 3.5 cm. Reconstruction was performed using anastomotic urethroplasty in 23 patients (65.7 %), while 12 required tissue transfer as a buccal mucosa graft (20.0 %) or penile island flap (14.3 %). With 50.5 months of follow-up, thirty patients (85.7 %) achieved cystoscopic patency with no significant difference between techniques (p = 0.32). A 90-day complication rate of 31.4 % was observed (all Clavien 1-2) with no difference between techniques (p = 1.00). Adverse change in continence occurred in 25.7 % of patients (13.3 % in those without previous TURP). Postoperatively, persisting storage LUTS occurred in 40.0 and 30.4 % described adverse change in erectile function (exclusively in the anastomotic urethroplasty group).

CONCLUSIONS

Reconstruction of radiation-induced bulbomembranous stenosis yields satisfying patency rates. However, radiation-induced urethral stenosis is not an isolated problem as many patients suffer from storage symptoms, erectile dysfunction or incontinence as a consequence of treatment either before or after urethroplasty.

Outcomes of Ventral Onlay Buccal Mucosa Graft Urethroplasty in Patients after Radiotherapy

PURPOSE

We evaluated stricture-free survival and functional outcomes of buccal mucosa graft urethroplasty in patients with urethral stricture disease after radiotherapy.

MATERIALS AND METHODS

We reviewed our urethroplasty database for patients with a radiotherapy history who underwent buccal mucosa graft urethroplasty between January 2009 and October 2013. We reviewed patient charts and the institutional, standardized, nonvalidated questionnaires administered to each patient postoperatively. Study end points included 1) the success rate, 2) continence status, 3) erectile function and 4) patient satisfaction postoperatively. Success was defined as stricture-free survival.

RESULTS

Of 38 men included in the study prostate cancer was the most common indication for radiotherapy in 35 (92.1%). External beam radiotherapy was performed in 24 cases (64.9%), brachytherapy was done in 8 (21.6%) and a combination of the 2 treatments was performed in 6 (13.5%). Strictures were in the bulbar/bulbomembranous urethra and had a median length of 3.0 cm (range 1.0 to 8.0). The overall success rate was 71.1% at a median followup of 26.5 months (range 1.0 to 50.0). Median time to stricture recurrence was 17.0 months (range 3.0 to 44.0). De novo urinary incontinence was observed in 4 patients (10.5%). Erectile function remained mostly unchanged compared to preoperative status. Study limitations include the small sample size and the lack of validated questionnaires.

CONCLUSIONS

At short-term to mid-term followup the success rate of ventral onlay buccal mucosa graft urethroplasty in patients with radiotherapy history seems acceptable. However, patients must be counseled about the increased risk of urinary incontinence. Longer followup is warranted to address long-term outcomes.

Urethral strictures and the cancer survivor

PURPOSE OF REVIEW

Urethral stricture disease is poorly understood in prostate cancer survivors who have undergone radiation or ablative treatments. We review the cause and incidence of urethral strictures (excluding bladder neck contracture) in this setting, as well as risk factors and treatment options.

RECENT FINDINGS

Stricture rates differ for various modalities of radiation therapy, with the highest rate in high-dose-rate brachytherapy. Risk factors include higher dose of radiation delivered to prostate apex, radiation delivered per treatment, and prior transurethral resection of prostate. Cryoablation and high-intensity focused ultrasound of the prostate also carry high risk of urethral stricture formation, particularly in the salvage setting. Dilation or direct vision incision of the urethra can be utilized as a temporizing technique, with frequent recurrence. Urethral stenting is also an option; however, this is associated with a high rate of incontinence. Urethroplasty has durable outcomes for radiation-induced strictures, with a preference for excision and primary anastomosis because of the bulbomembranous location and relatively short length of these strictures. Salvage radical prostatectomy has been described in a small series as treatment for posterior urethral strictures and bladder neck contractures resulting from ablative therapies.

SUMMARY

Prostate cancer survivors treated with radiation or ablative therapies are at risk for urethral stricture formation. Urethroplasty is a feasible and durable treatment option and should be considered in the appropriate patient.

Dosimetric analysis of urethral strictures following HDR (192)Ir brachytherapy as monotherapy for intermediate- and high-risk prostate cancer

BACKGROUND AND PURPOSE

To evaluate dosimetric parameters related to urethral strictures following high dose-rate brachytherapy (HDRBT) alone for prostate cancer.

MATERIAL AND METHODS

Ten strictures were identified in 213 patients treated with HDRBT alone receiving 34Gy in four fractions, 36Gy in four fractions, 31.5Gy in 3 fractions or 26Gy in 2 fractions. A matched-pair analysis used 2 controls for each case matched for dose fractionation schedule, pre-treatment IPSS score, number of needles used and clinical target volume. The urethra was divided into membranous urethra and inferior, mid and superior thirds of the prostatic urethra.

RESULTS

Stricture rates were 3% in the 34Gy group, 4% in the 36Gy group, 6% in the 31.5Gy group and 4% in the 26Gy group. The median time to stricture formation was 26months (range 8-40). The dosimetric parameters investigated were not statistically different between cases and controls. No correlation was seen between stricture rate and fractionation schedule.

CONCLUSIONS

Urethral stricture is an infrequent complication of prostate HDRBT when used to deliver high doses as sole treatment, with an overall incidence in this cohort of 10/213 (4.7%). In a matched pair analysis no association with dose schedule or urethral dosimetry was identified, but the small number of events limits definitive conclusions.

Expansion/de-expansion tool to quantify the accuracy of prostate contours

PURPOSE

Accurate delineation of the prostate gland on computed tomography (CT) remains a persistent challenge and continues to introduce geometric uncertainty into the planning and delivery of external beam radiotherapy. We, therefore, developed an expansion/de-expansion tool to quantify the contour errors and determine the location of the deviations.

METHODS AND MATERIALS

A planning CT scan and magnetic resonance imaging scan were prospectively acquired for 10 patients with prostate cancer. The prostate glands were contoured by 3 independent observers using the CT data sets with instructions to contour the prostate without underestimation but to minimize overestimation. The standard prostate for each patient was defined using magnetic resonance imaging and CT on multiple planes. After registration of the CT and magnetic resonance imaging data sets, the CT-defined prostates were scored for accuracy. The contours were defined as ideal if they were within a 2.5-mm expansion of the standard without underestimation, acceptable if they were within a 5.0-mm expansion and a 2.5-mm de-expansion, and unacceptable if they extended >5.0 mm or underestimated the prostate by >2.5 mm.

RESULTS

A total of 636 CT slices were individually analyzed, with the vast majority scored as ideal or acceptable. However, none of the 30 prostate contour sets had all the contours scored as ideal or acceptable. For all 3 observers, the unacceptable contours were more likely from underestimation than overestimation of the prostate. The errors were more common at the base and apex than the mid-gland.

CONCLUSIONS

The expansion/de-expansion tool allows for directed feedback on the location of contour deviations, as well as the determination of over- or underestimation of the prostate. This metric might help improve the accuracy of prostate contours.

Comparison of acute and late toxicities for three modern high-dose radiation treatment techniques for localized prostate cancer

PURPOSE

We compared acute and late genitourinary (GU) and gastrointestinal (GI) toxicities in prostate cancer patients treated with three different high-dose radiation techniques.

METHODS AND MATERIALS

A total of 1,903 patients with localized prostate cancer were treated with definitive RT at William Beaumont Hospital from 1992 to 2006: 22% with brachytherapy alone (BT), 55% with image-guided external beam (EB-IGRT), and 23% external beam with high-dose-rate brachytherapy boost (EBRT+HDR). Median dose with BT was 120 Gy for LDR and 38 Gy for HDR (9.5 Gy × 4). Median dose with EB-IGRT was 75.6 Gy (PTV) to prostate with or without seminal vesicles. For EBRT+HDR, the pelvis was treated to 46 Gy with an additional 19 Gy (9.5 Gy × 2) delivered via HDR. GI and GU toxicity was evaluated utilizing the NCI-CTC criteria (v.3.0). Median follow-up was 4.8 years.

RESULTS

The incidences of any acute ≥ Grade 2 GI or GU toxicities were 35%, 49%, and 55% for BT, EB-IGRT, and EBRT+HDR (p < 0.001). Any late GU toxicities ≥ Grade 2 were present in 22%, 21%, and 28% for BT, EB-IGRT, and EBRT+HDR (p = 0.01), respectively. Patients receiving EBRT+HDR had a higher incidence of urethral stricture and retention, whereas dysuria was most common in patients receiving BT. Any Grade ≥ 2 late GI toxicities were 2%, 20%, and 9% for BT, EB-IGRT, and EBRT+HDR (p < 0.001). Differences were most pronounced for rectal bleeding, with 3-year rates of 0.9%, 20%, and 6% (p < 0.001) for BT, EB-IGRT, and EBRT+HDR respectively.

CONCLUSIONS

Each of the three modern high-dose radiation techniques for localized prostate cancer offers a different toxicity profile. These data can help patients and physicians to make informed decisions regarding radiotherapy for prostate andenocarcinoma.

Management for prostate cancer treatment related posterior urethral and bladder neck stenosis with stents

PURPOSE

Prostate cancer treatment has the potential to lead to posterior urethral stricture. These strictures are sometimes recalcitrant to dilation and urethrotomy alone. We present our experience with the Urolume® stent for prostate cancer treatment related stricture.

MATERIALS AND METHODS

A total of 38 men with posterior urethral stricture secondary to prostate cancer treatment were treated with Urolume stenting. Stents were placed in all men after aggressive urethrotomy over the entire stricture. A successfully managed stricture was defined as open and stable for greater than 6 months after any necessary secondary procedures.

RESULTS

The initial success rate was 47%. After a total of 31 secondary procedures in 19 men, including additional stent placement in 8 (18%), the final success rate was 89% at a mean ± SD followup of 2.3 ± 2.5 years. Four cases (11%) in which treatment failed ultimately requiring urinary diversion (3) or salvage prostatectomy (1). Incontinence was noted in 30 men (82%), of whom 19 (63%) received an artificial urinary sphincter a mean of 7.2 ± 2.4 months after the stent. Subanalysis revealed that irradiated men had longer strictures (3.6 vs 2.0 cm, p = 0.003) and a higher post-stent incontinence rate (96% vs 50%, p < 0.001) than men who underwent prostatectomy alone but the initial failure rate was similar (54% vs 50%, p = 0.4).

CONCLUSIONS

Urolume stenting is a reasonable option for severe post-prostate cancer treatment stricture when patients are unwilling or unable to undergo open reconstructive surgery. Incontinence should be expected. The need for additional procedures is common and in some men may be required periodically for the lifetime of the stent.

Clinical results of iridium-192 high dose rate brachytherapy with external beam radiotherapy

OBJECTIVE

Here, we report the clinical results of iridium-192 high dose rate brachytherapy at Kanazawa University Hospital.

METHODS

The study population consisted of 166 patients diagnosed with T1c-T3bN0M0 prostate cancer treated with high dose rate brachytherapy and external beam radiotherapy and followed up for 6 months or longer. Treatment consisted of external beam radiotherapy to the prostate at 44 Gy/22 fractions and high dose rate brachytherapy at 18 Gy/3 fractions.

RESULTS

Median follow-up interval was 31.5 months (range 6.2-88.7). The overall 5-year biological recurrence-free survival rate was 93.0%. The 5-year biological recurrence-free survival rates for the patients in low-, intermediate- and high-risk groups according to the D'Amico risk classification criteria were 96.1%, 89.0% and 91.6%, respectively. When limited to the group that did not receive adjuvant hormonal therapy, the 5-year biological recurrence-free survival rates for the patients in low-, intermediate- and high-risk groups were 96.0%, 96.3% and 82.9%, respectively. Grade 3 or greater adverse effects were rare. Urethral stricture was observed in only 1.0% of the patients. Eighty percent of patients retained erectile function after high dose rate brachytherapy and reported satisfaction with sexual function.

CONCLUSIONS

High dose rate brachytherapy is considered a good form of treatment for localized prostate cancer, although longer follow-up is necessary.

Urethral stricture following high dose rate brachytherapy for prostate cancer

PURPOSE

To evaluate the incidence, timing, nature and outcome of urethral strictures following high dose rate brachytherapy (HDRB) for prostate carcinoma.

METHODS AND MATERIALS

Data from 474 patients with clinically localised prostate cancer treated with HDRB were analysed. Ninety percent received HDRB as a boost to external beam radiotherapy (HDRBB) and the remainder as monotherapy (HDRBM). Urethral strictures were graded according to the Common Terminology Criteria for Adverse Events v3.0.

RESULTS

At a median follow-up of 41 months, 38 patients (8%) were diagnosed with a urethral stricture (6-year actuarial risk 12%). Stricture location was bulbo-membranous (BM) urethra in 92.1%. The overall actuarial rate of grade 2 or more BM urethral stricture was estimated at 10.8% (95% CI 7.0-14.9%), with a median time to diagnosis of 22 months (range 10-68 months). All strictures were initially managed with either dilatation (n=15) or optical urethrotomy (n=20). Second line therapy was required in 17 cases (49%), third line in three cases (9%) and 1 patient open urethroplasty (grade 3 toxicity). Predictive factors on multivariate analysis were prior trans-urethral resection of prostate (hazard ratio (HR) 2.81, 95% CI 1.15-6.85, p=0.023); hypertension (HR 2.83, 95% CI 1.37-5.85, p=0.005); and dose per fraction used in HDR (HR for 1 Gy increase per fraction 1.33, 95% CI 1.08-1.64, p=0.008).

CONCLUSIONS

BM urethral strictures are the most common late grade 2 or more urinary toxicity following HDR brachytherapy for prostate cancer. Most are manageable with minimally invasive procedures. Both clinical and dosimetric factors appear to influence the risk of stricture formation.