High-dose-rate Brachytherapy For Prostate Cancer Research Articles

A Pilot Study of an Interactive Virtual Tour Tool for Patient Education Prior to Undergoing High-Dose Rate Brachytherapy for Prostate Cancer.

High-dose rate (HDR) brachytherapy for treatment of prostate cancer is an invasive procedure that can be associated with patient anxiety. Patient education regarding the procedure can allow for better informed decision-making while also decreasing anxiety. We sought to develop and assess the utility of an interactive virtual tour tool that portrays a 360-degree view of the HDR brachytherapy patient experience, with the goals of providing patient education, decreasing patient anxiety, and assisting in wayfinding on the procedure day. Using a 360-degree camera, we captured multiple photographs that depicted the various hospital locations that a patient would navigate through on the day of their HDR brachytherapy procedure, including the medical center lobby, pre-operative/post-operative units, and the brachytherapy suite. We then compiled these 360-degree photographs using virtual tour software, to allow users to navigate throughout the locations. We added informational text, spoken audio, and videos associated with key staff, objects, and the brachytherapy procedure that allow the users to interact with and learn about these various components within the virtual tour. This tool was accessible via a website link on a computer, tablet, or smartphone and was provided at the time of consult to patients who were planning to undergo HDR brachytherapy for prostate cancer. A questionnaire assessing the tool's ease of use, educational value, wayfinding utility, and ability to improve anxiety and treatment decision-making was conducted prior to and after their procedure. Preliminary feedback from healthy volunteers is highly positive, with users finding that the tool is easily accessible, user-friendly, improves understanding of HDR brachytherapy, simulates the treatment experience accurately, helps with wayfinding, and has the potential to decrease patient anxiety and increase comfort with the treatment decision. Data from the patient questionnaires are being collected and will be analyzed. A 360-degree virtual tour tool allows for an easily accessible, immersive, and interactive method of patient education on an invasive, anxiety-associated procedure. This has the potential to decrease patient anxiety and improve comfort regarding treatment decision-making. This tool may be applied toward other relatively involved radiotherapy modalities, including gynecologic HDR brachytherapy, respiratory-gated treatments, and CyberKnife stereotactic radiosurgery.

Reduction of toxicity in brachytherapy using a new technique

PurposeThe purpose of the study was to elucidate the usefulness of a dose evaluation method for reducing late genitourinary (GU) toxicity in high-dose-rate brachytherapy (HDR-BT) of prostate cancer. Methods and MaterialsGU toxicity was scored in accordance with the Common Terminology Criteria for Adverse Events version 4.0. The prostatic urethra was divided into three segments (base = B, midgland = M, apex = A), which were subclassified into seven subgroups (B, M, A, BM, BA, MA, BMA) using a D10% color map of the urethra. Significance testing was conducted on urethral D0.1% and D10% among the seven subgroups. Grade < 2 GU toxicity was also implemented. ResultsData of 174 patients with localized prostate cancer treated with HDR-BT combined with external beam radiotherapy between November 2011 and July 2014 were analyzed retrospectively. Median age was 74 (53–84) years, and median followup period was 44 (6–69) months. The number of Grade < 2 and Grade ≥ 2 toxicity was significantly different in the M subgroup than in the other subgroups (p < 0.05), suggesting increased radioresistance in the midgland urethra. ConclusionsA high-dose-area evaluation method using a urethral D10% color map may be helpful in reducing late GU toxicity in HDR-BT for prostate cancer.

Risk factors for urethral stricture following external beam radiotherapy and HDR brachytherapy for prostate cancer

PurposeA potential late side effect of high-dose-rate (HDR) prostate brachytherapy combined with external beam radiotherapy (EBRT) is urethral stricture. The purpose of this study was to evaluate dosimetric parameters possibly contributing to stricture development, including dose to bladder base and D2cc(Gy) within 10 mm of prostatic urethra (D2cc 10 mm), which has, so far, not been reported in the literature. Methods and MaterialsPatients developing urethral stricture, and matched controls, were identified from a prospective database of those receiving 46 Gy in 23 fractions of EBRT, followed by a single 15 Gy HDR brachytherapy dose. Patients had locally advanced, high- and intermediate-risk prostate cancer. Brachytherapy treatment planning parameters (planning target volume (PTV) size (cm 3), V110(%) bladder base, D2cc 10mm, number of HDR catheters, number of source dwell positions, and total source dwell time within 10 mm of the prostatic urethra) were analyzed to determine potential risk factors for urethral stricture. ResultsSeventy-two patients were treated, 22 of whom developed a urethral stricture. Univariate logistic regression performed on the planning parameters identified increased PTV size and D2cc 10 mm, with decreased V110(%) bladder base as risk factors for stricture formation. ConclusionsIt is suggested that PTV size, V110(%) bladder base, and D2cc 10mm are predictive of urethral stricture formation following EBRT and brachytherapy to the prostate. This study demonstrates the importance of minimizing high dwell times and hot spots close to organs at risk and also the correction of any craniocaudal movement of catheters to avoid potential hot spots in the bulbomembranous urethra where there may be increased dose sensitivity.

Incorporating Routine Magnetic Resonance Imaging-based Planning for the Delivery of High-dose-rate Brachytherapy for Prostate Cancer: An Evaluation of Clinical Feasibility and Dosimetric Outcomes.

IntroductionTo evaluate the implementation and dosimetric outcomes of magnetic resonance imaging (MRI) planning for improved target and normal tissue definition for the treatment of prostate cancer with high-dose-rate brachytherapy (HDRBT).MethodsFrom August 2015 to October 2017, 137 unique patients with newly diagnosed localized prostate cancer underwent a total of 174 outpatient brachytherapy procedures using MRI-based treatment planning. Patients receiving brachytherapy as monotherapy underwent two separate procedures while those receiving brachytherapy as a boost after external beam radiation therapy underwent a single procedure. The target volume was defined as the prostate +/- seminal vesicles as clinically appropriate without any additional margin. Pre-treatment dose-volume histogram (DVH) goals to the target were: D90≥95%, V90≥95%, V100≥90%, V150≤30%, V200≤15%. DVH goals to organs-at-risk (OARs): urethra D.01cc ≤115%, bladder D1cc ≤75%, rectum D1cc ≤75%, neurovascular bundle D0.1cc ≤100%, penile bulb D1cc ≤100%. Procedure times were recorded at each step of the procedure, from catheter insertion to removal.ResultsThe median target volume was 45.9 cc, the median volume receiving the prescription dose was 53.0 cc, and the median selectivity index was 0.9. The median values for target dosimetry were as follows: D90=99.9%, V90=95.7%, V100=90.1%, V150=28.1%, V200=10.5%. The median values for OAR dosimetry were: urethra D.01cc=114.3%, bladder D1cc=68.3%, rectum D1cc=51.8%, left neurovascular bundle D0.1cc=86.8%, right neurovascular bundle D0.1cc=88.5%, penile bulb D1cc=31.7%. The median time from catheter insertion to end of HDRBT delivery was four hours 14 minutes (range 2:56-9:08); total treatment package time was five hours 32 minutes (range 3:31-9:45).ConclusionRoutine MRI-based treatment planning is feasible for the delivery of HDRBT for prostate cancer. We met stringent dosimetric criteria despite more objective target and normal tissue definition with MRI imaging. Treatment package time remains reasonable. We have adopted MRI as our standard imaging modality for HDRBT for prostate cancer.

HDR brachytherapy invivo source position verification using a 2D diode array: A Monte Carlo study.

PurposeThis study aims to assess the accuracy of source position verification during high‐dose rate (HDR) prostate brachytherapy using a novel, in‐house developed two‐dimensional (2D) diode array (the Magic Plate), embedded exactly below the patient within a carbon fiber couch. The effect of tissue inhomogeneities on source localization accuracy is examined.MethodMonte Carlo (MC) simulations of 12 source positions from a HDR prostate brachytherapy treatment were performed using the Geant4 toolkit. An Ir‐192 Flexisource (Isodose Control, Veenendaal, the Netherlands) was simulated inside a voxelized patient geometry, and the dose deposited in each detector of the Magic Plate evaluated. The dose deposited in each detector was then used to localize the source position using a proprietary reconstruction algorithm.ResultsThe accuracy of source position verification using the Magic Plate embedded in the patient couch was found to be affected by the tissue inhomogeneities within the patient, with an average difference of 2.1 ± 0.8 mm (k = 1) between the Magic Plate predicted and known source positions. Recalculation of the simulations with all voxels assigned a density of water improved this verification accuracy to within 1 mm.ConclusionSource position verification using the Magic Plate during a HDR prostate brachytherapy treatment was examined using MC simulations. In a homogenous geometry (water), the Magic Plate was able to localize the source to within 1 mm, however, the verification accuracy was negatively affected by inhomogeneities; this can be corrected for by using density information obtained from CT, making the proposed tool attractive for use as a real‐time in vivo quality assurance (QA) device in HDR brachytherapy for prostate cancer.

Increasing Fractional Doses Increases the Probability of Benign PSA Bounce in Patients Undergoing Definitive HDR Brachytherapy for Prostate Cancer

Prostate-specific antigen (PSA) bounce is a temporary elevation of the PSA level above a prior nadir. The purpose of this study was to determine whether the frequency of a PSA bounce following high-dose-rate (HDR) interstitial brachytherapy for the treatment of prostate cancer is associated with individual treatment fraction size. Between 1999 and 2014, 554 patients underwent treatment of low- or intermediate-risk prostate cancer with definitive HDR brachytherapy as monotherapy and had ≥3 subsequent PSA measurements. Four different fraction sizes were used: 950cGy × 4 fractions, 1200cGy × 2 fractions, 1350cGy × 2 fractions, 1900cGy × 1 fraction. Four definitions of PSA bounce were applied: ≥0.2, ≥0.5, ≥1.0, and ≥2.0ng/mL above the prior nadir with a subsequent return to the nadir. The median follow-up period was 3.7years. The actuarial 3-year rate of PSA bounce for the entire cohort was 41.3%, 28.4%, 17.4%, and 6.8% for nadir +0.2, +0.5, +1.0, and +2.0ng/mL, respectively. The 3-year rate of PSA bounce >0.2ng/mL was 42.2%, 32.1%, 41.0%, and 59.1% for the 950-, 1200-, 1350-, and 1900-cGy/fraction levels, respectively (P=.002). The hazard ratio for bounce >0.2ng/mL for patients receiving a single fraction of 1900cGy compared with those receiving treatment in multiple fractions was 1.786 (P=.024). For patients treated with a single 1900-cGy fraction, the 1-, 2-, and 3-year rates of PSA bounce exceeding the Phoenix biochemical failure definition (nadir +2ng/mL) were 4.5%, 18.7%, and 18.7%, respectively, higher than the rates for all other administered dose levels (P=.025). The incidence of PSA bounce increases with single-fraction HDR treatment. Knowledge of posttreatment PSA kinetics may aid in decision making regarding management of potential biochemical failures.

Australian patterns of prostate cancer care: Are they evolving?

BackgroundApproaches to prostate cancer (PCa) care have changed in recent years out of concern for overdiagnosis and overtreatment. Despite these changes, many patients continue to undergo some form of curative treatment and with a growing perception among multidisciplinary clinicians that more aggressive treatments are being favored. This study examines patterns of PCa care in Australia, focusing on current rates of screening and aggressive interventions that consist of high-dose-rate (HDR) brachytherapy and pelvic lymph node dissection (PLND).MethodsHealth services data were used to assess Australian men undergoing PCa screening and treatment from 2001 to 2014. Age-specific rates of prostate-specific antigen (PSA) screening were calculated. Ratios of radical prostatectomy (RP) with PLND to RP without PLND, and HDR brachytherapy to low-dose-rate (LDR) brachytherapy were determined by state jurisdictions.ResultsFrom 2008, the rate of PSA screening trended downward significantly with year for all age ranges (P < 0.02) except men aged ≥ 85 (P = 0.56). PLND rates for 2008–2014 were lower than rates for 2001–2007 across all states and territories. From 2008 to 2014, PLND was performed ≥ 2.7 times more frequently in New South Wales and the Australian Capital Territory than in other jurisdictions. Since 2007, brachytherapy practice across Australia has evolved towards a relatively low use of HDR brachytherapy (ratio of HDR to LDR brachytherapy < 0.5 for all jurisdictions except the Australian Capital Territory).ConclusionRates of PLND and HDR brachytherapy for PCa have declined in Australia, providing evidence for the effect of stage migration due to widespread PSA screening. Currently, PSA screening rates remain high among older men, which may expose them to unnecessary investigations and treatment-related morbidity.

ACR Appropriateness Criteria high-dose-rate brachytherapy for prostate cancer

High-dose-rate (HDR) brachytherapy plays a potential curative role in the treatment of prostate cancer. An expert panel was convened to review the recent literature and reach a consensus on its appropriate clinical applications. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed every 2 years by a multidisciplinary expert panel. The guideline development and review include an extensive analysis of current medical literature from peer-reviewed journals and the application of a well-established consensus methodology (modified Delphi) to rate the appropriateness of imaging and treatment procedures by the panel. In those instances where evidence is lacking or not definitive, expert opinion may be used to recommend imaging or treatment. A summary of HDR brachytherapy's clinical applications and recent literature review was completed. Three clinical variants were developed to address common HDR dose, fractionations, and indications for its use in definitive therapy for primary and local recurrent prostate cancer. The panel reached a consensus on the specific treatment approaches with numerical rating and commentary. In combining available medical literature and expert opinion, this manuscript may serve as an aid for other practitioners in the appropriate application of HDR brachytherapy for prostate cancer.

Locally Recurrent Prostate Cancer After High-Dose-Rate Brachytherapy: The Value of Diffusion-Weighted Imaging, Dynamic Contrast-Enhanced MRI, and T2-Weighted Imaging in Localizing Tumors

The purpose of this article is to retrospectively evaluate the utility of prostate MRI for detecting locally recurrent prostate cancer after high-dose-rate (HDR) brachytherapy. Sixteen men with biochemical failure after HDR brachytherapy for prostate cancer underwent prostate MRI, including T2-weighted imaging, dynamic contrast-enhanced MRI (DCE-MRI), and diffusion-weighted imaging (DWI), using a 1.5-T MRI unit before 12-core-specimen biopsy. Two radiologists in consensus assessed the presence of tumor on each sequence within eight regions of the prostate (six from the peripheral zone [PZ] and two from the transition zone [TZ]) on the basis of biopsy. Biopsy revealed locally recurrent prostate cancer in 22 (17 in PZ and five in TZ) of 128 regions (17.2%). The sensitivity, specificity, and accuracy of each MRI method in the detection of recurrent tumor were 27%, 99%, and 87%, respectively, for T2-weighted imaging; 50%, 98%, and 90%, respectively, for DCE-MRI; and 68%, 95%, and 91%, respectively, for DWI. The sensitivity of DWI in detecting recurrent tumor was significantly higher than that of T2-weighted imaging (p = 0.004). Multiparametric MRI achieved the highest sensitivity (77%) but with slightly decreased specificity (92%). These results indicate that a multiparametric MRI protocol that includes DWI provides a sensitive method to detect local recurrence after HDR brachytherapy.

Previous transurethral resection of the prostate is not a contraindication to high‐dose rate brachytherapy for prostate cancer

To analyse retrospectively the morbidity and efficacy of high-dose rate (HDR) brachytherapy in patients who had a previous transurethral resection of the prostate (TURP). Morbidities documented in the records of 32 patients with previous TURP and 106 with no previous TURP, treated with HDR brachytherapy for prostate cancer at our institution, were analysed and compared. All patients received HDR brachytherapy as a boost before conformal external beam radiotherapy. We recorded and analysed genitourinary complications, rectal morbidity, and the biochemical control rate as assessed by the prostate-specific antigen (PSA) level. All complications of patients who received HDR brachytherapy were recorded during the follow-up. All gastrointestinal and genitourinary complications were not significantly different in patients with or without previous TURP. There was little incontinence or severe morbidity associated with HDR brachytherapy. The PSA-based biochemical control rates were similar in patients with or without previous TURP in each risk group. HDR brachytherapy is a reasonable treatment for localized prostate cancer in patients who have had a previous TURP, with the expectation of low morbidity and satisfactory biochemical control.

Interstitial high-dose-rate brachytherapy and local anesthesia for prostate cancer: A feasibility report

High-dose-rate brachytherapy (HDR-BT) to treat prostate cancer is usually performed with the patient under general or spinal anesthesia. This report describes how patients tolerate HDR-BT under local anesthesia and provides technical detail, quantifies discomfort level, and summarizes time required for the procedure. Eleven patients with locally advanced prostate cancer, classified as intermediate or high risk, were treated based on an institutional protocol combining HDR-BT and hypofractionated external-beam radiotherapy. For HDR-BT treatments, patients submitted to two weekly implants. To date, we have performed 22 implantations in 11 patients. The dose of lidocaine administered ranged from 250 to 500 mg (median, 300 mg) and pain score ranged from 2 to 6 (median, 3-4). We conclude that HDR-BT for prostate cancer with the patient under local anesthesia is efficient in terms of resource use and personnel time and will facilitate and expand the use of HDR-BT at our institution and others with few beds.

High-dose-rate brachytherapy for large prostate volumes (≥50 cc)—Uncompromised dosimetric coverage and acceptable toxicity

Purpose The purpose of this study was to review our single-institution experience using high-dose-rate (HDR) brachytherapy in patients with large-volume prostate glands (≥50 cc). Methods and materials Fifty-four patients treated with HDR brachytherapy for prostate cancer at the Penrose Cancer Center between 2001 and 2006 were identified as having an ultrasound volume of at least 50 cc at the time of implant (range, 50–97.3 cc; mean, 61.5 cc; median, 57 cc; upper quartile, 83.3–97.3 cc). Neoadjuvant hormones (17 patients) were not routinely recommended unless the initial ultrasound volume suggested pubic arch interference or the patient's Gleason score or prostate specific antigen prompted use. All patients received HDR brachytherapy as a boost before or after conformal external beam radiation therapy to 4500 cGy. Boost brachytherapy doses ranged from 1600 to 1900 cGy, given in two to three fractions. Results The median D 90 (minimal dose to 90% of the prostate) was 109% of prescription dose (range, 95–115%) and the median V 100 (volume receiving 100% of the dose) was 96% (range, 90–99%). V 150 ranged from 10% to 35%, with a median value of 18.3%. Six patients (11%) required temporary placement of a urinary catheter for acute obstructive symptoms after brachytherapy. With a median followup of 1.8 years, there has been a single case of Grade 2 gastrointestinal toxicity and 1 patient has developed a bulbo-urethral stricture requiring dilation. There have been no cases of rectal bleeding. Conclusions Large prostate volume is not a contraindication to HDR brachytherapy. Excellent dosimetric coverage can be attained with acceptable acute toxicity.

Early observed transient prostate-specific antigen elevations on a pilot study of external beam radiation therapy and fractionated MRI guided High Dose Rate brachytherapy boost

PurposeTo report early observation of transient PSA elevations on this pilot study of external beam radiation therapy and magnetic resonance imaging (MRI) guided high dose rate (HDR) brachytherapy boost.Materials and methodsEleven patients with intermediate-risk and high-risk localized prostate cancer received MRI guided HDR brachytherapy (10.5 Gy each fraction) before and after a course of external beam radiotherapy (46 Gy). Two patients continued on hormones during follow-up and were censored for this analysis. Four patients discontinued hormone therapy after RT. Five patients did not receive hormones. PSA bounce is defined as a rise in PSA values with a subsequent fall below the nadir value or to below 20% of the maximum PSA level. Six previously published definitions of biochemical failure to distinguish true failure from were tested: definition 1, rise >0.2 ng/mL; definition 2, rise >0.4 ng/mL; definition 3, rise >35% of previous value; definition 4, ASTRO defined guidelines, definition 5 nadir + 2 ng/ml, and definition 6, nadir + 3 ng/ml.ResultsMedian follow-up was 24 months (range 18–36 mo). During follow-up, the incidence of transient PSA elevation was: 55% for definition 1, 44% for definition 2, 55% for definition 3, 33% for definition 4, 11% for definition 5, and 11% for definition 6.ConclusionWe observed a substantial incidence of transient elevations in PSA following combined external beam radiation and HDR brachytherapy for prostate cancer. Such elevations seem to be self-limited and should not trigger initiation of salvage therapies. No definition of failure was completely predictive.

Anatomy-based inverse optimization in high-dose-rate brachytherapy combined with hypofractionated external beam radiotherapy for localized prostate cancer: Comparison of incidence of acute genitourinary toxicity between anatomy-based inverse optimization and geometric optimization

To evaluate the advantages of anatomy-based inverse optimization (IO) in planning high-dose-rate (HDR) brachytherapy. A total of 114 patients who received HDR brachytherapy (9 Gy in two fractions) combined with hypofractionated external beam radiotherapy (EBRT) were analyzed. The dose distributions of HDR brachytherapy were optimized using geometric optimization (GO) in 70 patients and by anatomy-based IO in the remaining 44 patients. The correlation between the dose-volume histogram parameters, including the urethral dose and the incidence of acute genitourinary (GU) toxicity, was evaluated. The averaged values of the percentage of volume receiving 80-150% of the prescribed minimal peripheral dose (V(80)-V(150)) of the urethra generated by anatomy-based IO were significantly lower than the corresponding values generated by GO. Similarly, the averaged values of the minimal dose received by 5-50% of the target volume (D(5)-D(50)) obtained using anatomy-based IO were significantly lower than those obtained using GO. Regarding acute toxicity, Grade 2 or worse acute GU toxicity developed in 23% of all patients, but was significantly lower in patients for whom anatomy-based IO (16%) was used than in those for whom GO was used (37%), consistent with the reduced urethral dose (p <0.01). The results of this study suggest that anatomy-based IO is superior to GO for dose optimization in HDR brachytherapy for prostate cancer.

Dose-volume impact in high-dose-rate Iridium-192 brachytherapy as a boost to external beam radiotherapy for localized prostate cancer- a phase II study

Background and purpose Evaluation of dose-volume–time-related factors in 64 patients treated with high-dose-rate brachytherapy (HDR-BT) as a boost to external beam radiotherapy (EBRT) for localized prostate cancer. Patients and methods Clinical parameters were correlated with morbidity scores of the EPIC (Expanded Prostate Cancer Index) questionnaire. Median time after radiotherapy (HDR-BT up to 18 Gy in two fractions and EBRT up to a median dose of 50.4 Gy) was 1.5 and 3 years (first and second questionnaire). Results A significant impact of a urethra D1 exceeding 15 Gy in at least one HDR fraction concerning urinary morbidity and a rectum D1 exceeding 6 Gy to the rectal mucosa in the first and second HDR fraction concerning the rectal bleeding rate was found. A higher number of needles was associated with lower urinary and bowel scores after 1.5 years. A prostate length >4.8 cm and a longer duration of EBRT (independently of the dose) predisposed for lower urinary and bowel scores. In contrast to a urethra D1>15 Gy as an independent factor, a rectum D1>6 Gy per HDR fraction correlated with a higher number of needles and an increased prostate length. Conclusions To minimize morbidity in HDR-BT for prostate cancer, a maximum dose to the urethra of 15 Gy and a maximum dose to the rectal mucosa of 6 Gy is advisable. Treatment- and patient-related factors have a major impact on toxicity.