Is single fraction 15Gy the preferred high dose-rate brachytherapy boost dose for prostate cancer?

Prospective study of HDR brachytherapy (BT), external beam radiotherapy (EBRT) and androgen deprivation therapy (ADT): 10-years experience of an MRI-guided approach

OBJECTIVES

To evaluate the predictive factors for biochemical failure and distant metastases in a prospective cohort of patients with localized prostate cancer treated with the combination of HDR BT and EBRT.

METHODS AND MATERIALS

Patients with intermediate (IR) or high-risk (HR) prostate adenocarcinoma received a single fraction of HDR of 15 Gy combined with RT of 37.5 Gy in 15 fractions. ADT duration was used depending on risk-group. Descriptive analyses were performed. Univariate and multivariate Hazard Ratios were obtained. Finally, the Kaplan-Meier model was used to describe the survival of the events of interest.

RESULTS

309 patients were treated prospectively (199 were IR and 110 HR). Median age was 72 years; 58.3 % were MRI stage ≤ T2c, 34.1 % T3a and 7.6 % T3b; ISUP-grade 1-3 in 78.9 % and ISUP 4-5 in 21.1 %. 71.8 % of patients had ≤ 50 % positive-cores in biopsy and 28.2 % had > 50 %. Median pre-treatment PSA was 9.9 ng/mL. After a median follow-up of 88 months, 41 patients presented biochemical failure and 18 developed distant metastases. Multivariate cox-regression analyses found that MR-T3b Stage (HR 3.88, p = 0.001) and ADT use (HR 3.99, p = 0.03) were the only predictive factors for biochemical failure and the number of positive cores (>50 %) the only independent predictive factor of distant metastases (HR 4.36, p = 0.002).

CONCLUSIONS

Patients with mpMRI evidence of invasion of the SV and involvement of more than 50% of the cores in the prostate biopsy are patients with a higher risk of presenting a biochemical recurrence or developing metastasis due to their prostate cancer, respectively.

Implementation of High-Dose-Rate, CT-Based Prostate Brachytherapy in an Academic Teaching Hospital and Residency Training Program

Introduction Prostate brachytherapy provides the most durable local control for prostate adenocarcinoma among all radiation treatment options. However, likely due to decreased trainee familiarity with the technique and resource intensity, it has seen a decline in utilization. Here we outline our experience with starting a high-dose-rate (HDR) prostate brachytherapy program within a residency training program and present our outcome data. Methods Patients were identified and screened using clinical data and volume study for candidacy for brachytherapy implantation. Eligible candidates were implanted and subsequently had radiation planning and delivery in our clinic. Descriptive statistical analysis was performed on our outcomes and dosimetry data and presented in tabular form. Results Seventeen patients were treated for a total of 18 implants (one monotherapy). No implant was aborted. No acute urinary retention requiring catheterization or chronic urethral stricture occurred. Biochemical recurrence-free survival was 94% at a median follow-up of 28.5 months (range 8.2-50 months); the one failure occurred in a very high-risk patient at 37 months following treatment. Dosimetrically, prostate coverage, urethra sparing, and rectum sparing aims were met. Volumetric bladder aims were also met; however, the max point dose to the bladder neck was above the guideline. Conclusion Our department successfully implemented an HDR prostate brachytherapy program. Treatments were effective and there was no grade 3 toxicity to report.

Prostate cancer brachytherapy: SFRO guidelines 2021

Prostate brachytherapy techniques are described, concerning both permanent seed implant and high dose rate brachytherapy. The following guidelines are presented: brachytherapy indications, implant procedure for permanent low dose rate implants and high dose rate with source projector, as well as dose and dose-constraints objectives, immediate postoperative management, post-treatment evaluation, and long-term follow-up.

Low-/high-dose-rate brachytherapy boost in patients with intermediate-risk prostate cancer treated with radiotherapy: long-term results from a single institution team experience

Purpose

To compare brachytherapy (BT) boost of low-dose-rate (LDR) and high-dose-rate (HDR) techniques in patients diagnosed with intermediate-risk prostate cancer.

Material and methods

Between January 2005 and February 2018, 142 patients (50 LDR and 92 HDR) with intermediate-risk prostate cancer were treated with a BT boost, and retrospectively analyzed. Prescribed dose was 45 Gy with external beam radiotherapy (EBRT) plus 100-108 Gy with LDR-BT, and 60 Gy with EBRT plus one fraction of 10 Gy with HDR-BT. 99% of patients received androgen deprivation therapy (ADT) for 6 months. Primary endpoint was to compare LDR and HDR boosts in terms of biochemical progression-free survival (bPFS). Secondary endpoint, after re-classifying patients into "favorable" and "unfavorable" sub-groups, was to analyze differences with a similar treatment intensity.

Results

Median overall follow-up for the total cohort was 66.5 months (range, 16-185 months). There were no significant differences in bPFS, overall survival, cause specific survival, local failure, lymph node failure, or distant failure when LDR or HDR was employed. bPFS at 90 months was 100% for favorable, and 89% and 85% for unfavorable patients at 60 months and 90 months, respectively (log-rank test, p = 0.017). The crude incidence of genitourinary acute and chronic toxicity grade 3 was 0.7% and 4%, respectively. Twelve patients (8%) had chronic rectal hemorrhage grade 2, in whom argon was applied (4 LDR and 8 HDR).

Conclusions

Combined treatment is an excellent therapeutic option in patients with intermediate-risk prostate carcinoma, with similar results in both LDR and HDR approaches and very low toxicities. Importantly, the current literature has indicated that unfavorable-risk patients belong to a different category, and should be treated as patients with high-risk factors. Therefore, the stratification and identification of both risk groups is extremely relevant.

Complications and side effects of high-dose-rate prostate brachytherapy

PURPOSE

To describe technical challenges and complications encountered during and after high-dose-rate prostate brachytherapy (HDR-BT) and review management of these complications.

METHODS AND MATERIALS

The authors performed a systematic review of the literature on toxicities encountered after prostate HDR-BT +/- external beam radiotherapy. A total of 397 studies were identified, of which 64 were included. A focused review of literature regarding the management of acute and late toxicities also performed.

RESULTS

Most acute toxicities include grade 0-2 genitourinary and gastrointestinal toxicity. Overall, Grade 3+ Common Terminology Criteria for Adverse Events toxicity after HDR-BT was low [genitourinary: 0-1%; gastrointestinal 0-3%]. Rates of fistula formation were <1%, and radiation cystitis/proctitis were <14% and more commonly reported in cohorts treated with HDR-BT boost and external beam radiotherapy.

CONCLUSIONS

HDR-BT both as monotherapy or combined with external beam radiotherapy for prostate cancer is well tolerated. Serious complications are rare.

169 Yb-based rotating shield brachytherapy for prostate cancer

PURPOSE

To present a system for the treatment of prostate cancer in a single-fraction regimen using ¹⁶⁹ Yb-based rotating shield brachytherapy (RSBT) with a single-catheter robotic delivery system. The proposed system is innovative because it can deliver RSBT through multiple implanted needles independently, in serial, using flexible catheters, with no inter-needle shielding effects and without the need to rotate multiple shielded catheters inside the needles simultaneously, resulting in a simple, mechanically robust, delivery approach. RSBT was compared to conventional ¹⁹² Ir-based high-dose-rate brachytherapy (HDR-BT) in a treatment planning study with dose escalation and urethral sparing goals, representing single-fraction brachytherapy monotherapy and brachytherapy as a boost to external beam radiotherapy, respectively. A prototype mechanical delivery system was constructed and quantitatively evaluated as a proof of concept.

METHODS

Treatment plans for twenty-six patients with single fraction prescriptions of 20.5 and 15 Gy, were created for dose escalation and urethral sparing, respectively. The RSBT and HDR-BT delivery systems were modeled with one partially shielded 999 GBq (27 Ci) ¹⁶⁹ Yb source and one 370 GBq (10 Ci) ¹⁹² Ir source, respectively. A prototype angular drive system for helical source delivery was constructed. Mechanical accuracy measurements of source translational position and angular orientation in a simulated treatment delivery setup were obtained using the prototype system.

RESULTS

For dose escalation, with equivalent urethra D_10% , PTV D_90% for RSBT vs HDR-BT increased from 22.6 ± 0.0 Gy (average ± standard deviation) to 29.3 ± 0.9 Gy, or 29.9 % ± 3.0%, with treatment times of 51.4 ± 6.1 min for RSBT and 15.8 ± 2.3 min for 10 Ci ¹⁹² Ir-based HDR-BT. For urethra sparing, with equivalent PTV D_{90 %} , urethra D_10% for RSBT vs HDR-BT decreased for RSBT vs HDR-BT from 15.6 ± 0.4 Gy to 12.0 ± 0.4 Gy, or 23.1% ± 3.5%, with treatment times of 30.0 ± 3.7 min for RSBT and 12.3 ± 1.8 min for HDR-BT. Differences between measured vs predicted rotating catheter positions (corresponding to source position) were within 0.18 mm ± 0.12 mm longitudinally and 0.07° ± 0.78°.

CONCLUSION

¹⁶⁹ Yb-based RSBT can increase PTV D_90% or decrease urethral D_10% relative to HDR-BT with treatment times of less than 1 h using a single-source robotic delivery system with treatment delivered in a single fraction. The prototype helical delivery system was able to demonstrate adequate mechanical accuracy.

Implementation of high-dose-rate brachytherapy for prostatic carcinoma in an unshielded operating room facility

PURPOSE

The purpose of the study was to describe our approach towards safe delivery of single-fraction high-dose-rate (HDR) brachytherapy (BT) boost in patients with prostate cancer in the setting of an unshielded operating room (OR).

METHODS AND MATERIALS

A total of 95 patients received 15 Gy HDR BT boost. The procedure involved transrectal ultrasound-based catheter insertion and planning in the OR, after which the patient was moved to a shielded treatment room for radiation. This required three vital components: (1) an OR table capable of transporting the patient in lithotomy position, (2) robust motion management checks to ensure reproducibility of prostate and catheter positions in the treatment room before radiation delivery, (3) remote monitoring of patient vitals while under anesthesia, during the radiation. Initial viability of this approach was confirmed by assessing acute toxicities using the Common Terminology Criteria for Adverse Events v4.0 and American Urologic Association symptom scores.

RESULTS

We found good stability in prostate and catheter position, with less than 1 mm shifts in each direction due to patient transfer. The median baseline American Urologic Association score was 7 (3-11), which increased to 12 (7-17) at 4 weeks and 9 (5-14) at 3 months (p = 0.003). Common Terminology Criteria for Adverse Events ≥ grade 2 genitourinary and gastrointestinal toxicities were experienced by 7% and 0% patients, respectively, at 3 months posttreatment completion.

CONCLUSIONS

Single-fraction HDR prostate BT can be delivered safely in an unshielded OR facility with a distant shielded treatment room using rigorous motion management checks and supplementary procedural equipment.

Does ADT benefit unfavourable intermediate risk prostate cancer patients treated with brachytherapy boost and external beam radiotherapy? A propensity-score matched analysis

PURPOSE

To investigate the role of androgen deprivation therapy (ADT) in unfavorable intermediate risk (UIR) prostate cancer patients treated with high-dose rate (HDR) brachytherapy (BT) boost.

MATERIAL AND METHODS

Data from 326 consecutive NCCN UIR prostate cancer patients treated in a single institution from 2009 to 2016 with 15 Gy HDR-BT boost plus 37.5 Gy external beam radiotherapy (EBRT) in 15 fractions to prostate and proximal seminal vesicles were retrospectively collected. Baseline information was collected and patients receiving vs. not receiving ADT were matched using a propensity-score model. Primary endpoint was biochemical-failure-free survival (BFFS). Kaplan-Meier estimates and stratified log-rank tests (adjusting for matched design) were used to compare BFFS, castration-resistance (CRFS) and metastasis free survival (MFS) outcomes between both groups.

RESULTS

A total of 326 patients were included in the analysis of which 52 ADT patients were matched to 104 non-ADT patients in a 1:2 ratio. Median follow-up was 3.4 years and 5.5 years for ADT and non-ADT respectively. No significant baseline differences were observed. ADT was used for a median total time of 6 months (interquartile range [IQR]: 4-6) and delivered a median time of 2.7 months (IQR: 1.7-4.3) prior to HDR-BT. BFFS was significantly improved in the ADT group (stratified log-rank: p = 0.043) with 3-year and 6-year BFFS of 98% and 90% for the ADT group and 92% and 82% for the non-ADT group, respectively. No significant differences were detected for CRFS or MFS.

CONCLUSION

Short-term ADT increased BFFS in UIR prostate cancer patients treated with HDR-BT boost plus EBRT.

A phase IB clinical trial of 15 Gy HDR brachytherapy followed by hypofractionated/SBRT in the management of intermediate-risk prostate cancer

PURPOSE

High dose-rate (HDR) brachytherapy is commonly administered as a boost to external beam radiation therapy (EBRT). Our purpose was to compare toxicity with increasingly hypofractionated EBRT in combination with a single 15 Gy HDR boost for men with intermediate-risk prostate cancer.

METHODS AND MATERIALS

Forty-two men were enrolled on this phase IB clinical trial to one of three EBRT dose cohorts: 10 fractions, seven fractions, or five fractions. Patients were followed prospectively for safety, efficacy, and health-related quality of life (Expanded Prostate Index Composite). Efficacy was assessed biochemically using the Phoenix definition.

RESULTS

With a median follow up of 36 months, the biochemical disease-free survival was 95.5%. One man developed metastatic disease at 5 years. There was no significant minimally important difference in EPIC PRO for either urinary, bowel, or sexual domains. There was one acute Grade 3 GI and GU toxicity, but no late Grade 3 GU or GI toxicities.

CONCLUSION

Fifteen gray HDR brachytherapy followed by a five fraction SBRT approach results in high disease control rates and low toxicity similar to previously reported HDR protocols with significant improvement in patient convenience and resource savings. While mature results with longer follow up are awaited, this treatment approach may be considered a safe and effective option for men with intermediate-risk disease.

High Dose Rate Brachytherapy in High-Risk Localised Disease - Why Do Anything Else?

The management of high-risk prostate cancer is challenging, as patients have a high risk of both local and distant relapse. Although adjuvant systemic treatment remains an important component of management, for those receiving radiotherapy, optimal local treatment should include a brachytherapy boost. This may be given by low dose rate (LDR) or high dose rate (HDR) techniques, but HDR has several advantages over LDR by virtue of more consistent dose optimisation, ability to treat outside the prostate and lower toxicity. A significant body of evidence now supports the use of HDR brachytherapy in addition to supplementary pelvic external beam radiotherapy for men with high-risk disease. Consistent evidence has emerged from randomised clinical trials, meta-analyses, and from institutional and multicentre cohort studies. It has been shown to improve local disease control and possibly reduce metastases and improve cancer-specific survival compared with external beam radiotherapy alone. It should be considered as standard treatment.

A comparison of outcomes for patients with intermediate and high risk prostate cancer treated with low dose rate and high dose rate brachytherapy in combination with external beam radiotherapy

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Superior biochemical progression free survival for LDR in combination with EBRT.

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On multivariable analysis, HDR and EBRT and Gleason ≥8 predicted for progression.

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Low cumulative incidence of ≥grade 3 GU and GI toxicities.

Introduction

There is evidence to support use of external beam radiotherapy (EBRT) in combination with both low dose rate brachytherapy (LDR–EBRT) and high dose rate brachytherapy (HDR–EBRT) to treat intermediate and high risk prostate cancer.

Methods

Men with intermediate and high risk prostate cancer treated using LDR–EBRT (treated between 1996 and 2007) and HDR–EBRT (treated between 2007 and 2012) were identified from an institutional database. Multivariable analysis was performed to evaluate the relationship between patient, disease and treatment factors with biochemical progression free survival (bPFS).

Results

116 men were treated with LDR-EBRT and 171 were treated with HDR–EBRT. At 5 years, bPFS was estimated to be 90.5% for the LDR–EBRT cohort and 77.6% for the HDR–EBRT cohort. On multivariable analysis, patients treated with HDR–EBRT were more than twice as likely to experience biochemical progression compared with LDR–EBRT (HR 2.33, 95% CI 1.12–4.07). Patients with Gleason ≥8 disease were more than five times more likely to experience biochemical progression compared with Gleason 6 disease (HR 5.47, 95% CI 1.26–23.64). Cumulative incidence of ≥grade 3 genitourinary and gastrointestinal toxicities for the LDR–EBRT and HDR–EBRT cohorts were 8% versus 4% and 5% versus 1% respectively, although these differences did not reach statistical significance.

Conclusion

LDR–EBRT may provide more effective PSA control at 5 years compared with HDR–EBRT. Direct comparison of these treatments through randomised trials are recommended to investigate this hypothesis further.

Results of 15 Gy HDR-BT boost plus EBRT in intermediate-risk prostate cancer: Analysis of over 500 patients

PURPOSE/OBJECTIVE

To report biochemical control associated with single fraction 15 Gy high-dose-rate brachytherapy (HDR-BT) boost followed by external beam radiation (EBRT) in patients with intermediate-risk prostate cancer.

MATERIALS AND METHODS

A retrospective chart review of all patients with intermediate-risk disease treated with a real-time ultrasound-based 15 Gy HDR-BT boost followed by EBRT between 2009 and 2016 at a single quaternary cancer center was performed. Freedom from biochemical failure (FFBF), cumulative incidence of androgen deprivation therapy use for biochemical or clinical failure post-treatment (CI of ADT) and metastasis-free survival (MFS) outcomes were measured.

RESULTS

518 patients met the inclusion criteria for this study. Median age at HDR-BT was 67 years (IQR 61-72). 506 (98%) had complete pathologic information available. Of these, 146 (28%) had favorable (FIR) and 360 (69%) had unfavorable (UIR) intermediate-risk disease. 83 (16%) received short course hormones with EBRT + HDR. Median overall follow-up was 5.2 years. FFBF was 91 (88-94)% at 5 years. Five-year FFBF was 94 (89-99)% and 89 (85-94)% in FIR and UIR patients, respectively (p = 0.045). CI of ADT was 4 (2-6)% at 5 years. Five-year CI of ADT was 1 (0-3)% and 5 (2-8)% in FIR and UIR patients, respectively (p = 0.085). MFS was 97 (95-98)% at 5 years. Five-year MFS was 100 (N/A-100)% and 95 (92-98)% in FIR and UIR patients, respectively (p = 0.020).

CONCLUSION

In this large cohort of intermediate-risk prostate cancer patients, 15 Gy HDR-BT boost plus EBRT results in durable biochemical control and low rates of ADT use for biochemical failure.

[Moderate or extreme hypofractionation and localized prostate cancer: The times are changing]

There are many treatment options for localized prostate cancers, including active surveillance, brachytherapy, external beam radiotherapy, and radical prostatectomy. Quality of life remains a primary objective in the absence of superiority of one strategy over another in terms of specific survival with similar long-term biochemical control rates. Despite a significant decrease in digestive and urinary toxicities thanks to IMRT and IGRT, external radiotherapy remains a treatment that lasts approximately 2 months or 1.5 months, when combined with a brachytherapy boost. Given the specific radiosensitivity of this tumor, several randomized studies have shown that a hypofractionated scheme is not inferior in terms of biochemical control and toxicities, allowing to divide the number of fractions by a factor 2 to 8. Given that SBRT becomes a validated therapeutic option for a selected population of patients with localized prostate cancer, extreme hypofractionation is becoming a strong challenger of conventional external radiotherapy or brachytherapy.

Absolute percentage of biopsied tissue positive for Gleason pattern 4 disease (APP4) appears predictive of disease control after high dose rate brachytherapy and external beam radiotherapy in intermediate risk prostate cancer

BACKGROUND AND PURPOSE

To identify if, in intermediate risk prostate cancer (IR-PCa), the absolute percentage of biopsied tissue positive for pattern 4 disease (APP4) may be a predictor of outcome.

MATERIALS AND METHODS

411 patients with IR-PCa were retrospectively reviewed. APP4 was calculated based on biopsy reports. Multivariable competing risk analysis was then performed on optimized APP4 cutpoints to predict for biochemical failure (BF), androgen deprivation use for BF (ADT-BF) and development of metastases (MD).

RESULTS

Median follow-up for the cohort was 5.2 (Inter Quartile Range: 2.9-6.6) years. Median baseline PSA was 7.3 (5.3-9.8) ng/mL. 234 (56.9%) patients had T1 and 177 (43.1%) had T2 disease. Median APP4 was 2.00 (0.75-7.50)%. 38 (9.3%) patients experienced BF. The optimal cutpoint of APP4 for BF was >3.3% with an area under the curve (AUC) of 0.66. 17 (4.1%) received ADT-BF. The ADT-BF cutpoint was >6.6% with an AUC of 0.72. Eight (2.0%) developed MD. The MD cutpoint was >17.5% with an AUC of 0.86. Using APP4 >3.3 vs ≤ 3.3, log-transformed baseline PSA ln(PSA) (HR 2.5, 1.1-6.1; p = 0.037) and APP4 (HR 2.3, 1.1-4.7; p = 0.031) predicted for BF. Using APP4 >6.6 vs ≤ 6.6, ln(PSA) (HR 4.2, 1.4-12.4; p = 0.010) and APP4 (HR 3.7, 1.4-10.0; p = 0.009) were predictive of ADT-BF. APP4 >17.5 vs ≤ 17.5 alone was predictive of MD (HR 25.7, 4.9-135.3; p < 0.001).

CONCLUSION

APP4 cutpoints of >3.3%, >6.6% and >17.5% were strongly associated with increased risk of BF, ADT-BF and developing MD respectively. These findings may inform future practice when treating IR-PCa but require external validation.

Brachytherapy for localized prostate cancer in the modern era: a comparison of patient-reported quality of life outcomes among different techniques

Purpose

To report our institutional quality of life (QOL) data for low-dose-rate (LDR) monotherapy (LDR mono), high-dose-rate (HDR) monotherapy (HDR mono), and EBRT with an HDR brachytherapy boost (HDR boost).

Material and methods

The charts of 165 patients with localized adenocarcinoma of the prostate treated with LDR monotherapy (LDR mono), HDR monotherapy (HDR mono), and EBRT with an HDR brachytherapy boost (HDR boost) at a single institution between 2012 and 2015 were reviewed. All patients completed the American Urological Association symptom score (AUASS) and Expanded Prostate Index for Prostate Cancer - Clinical Practice (EPIC-CP) quality of life assessments prior to treatment and at least one follow-up survey. Time points included baseline, ≤ 2 months, 2-≤ 6 months, 6-≤ 12 months, 12-≤ 18 months, 18-≤ 24 months, 24-≤ 30 months, and > 30 months. Linear mixed models were performed to test for significant changes and differences in each outcome over time.

Results

Mean follow-up was 19.5 months. All major functional QOL domains were affected after treatment with brachytherapy for localized prostate cancer. All domains improved over time, with the exception of sexual function scores for all groups and urinary incontinence scores for the HDR mono group. Patients treated with LDR did have higher AUA, irritability/obstructive symptoms, incontinence, bowel, and QOL scores acutely compared to the HDR and HDR + boost groups. Vitality scores were significantly worse in the HDR boost group both acutely and at the > 30-month time point.

Conclusions

Patients receiving HDR brachytherapy had lower acute urinary and rectal toxicity compared to the patients receiving LDR, even when combined with EBRT. However, long-term toxicity was similar.

Transitioning From a Low-Dose-Rate to a High-Dose-Rate Prostate Brachytherapy Program: Comparing Initial Dosimetry and Improving Workflow Efficiency Through Targeted Interventions

Purpose

We transitioned from a low-dose-rate (LDR) to a high-dose-rate (HDR) prostate brachytherapy program. The objective of this study was to describe our experience developing a prostate HDR program, compare the LDR and HDR dosimetry, and identify the impact of several targeted interventions in the HDR workflow to improve efficiency.

Methods and Materials

We performed a retrospective cohort study of patients treated with LDR or HDR prostate brachytherapy. We used iodine-125 seeds (145 Gy as monotherapy, and 110 Gy as a boost) and preoperative planning for LDR. For HDR, we used iridium-192 (13.5 Gy × 2 as monotherapy and 15 Gy × 1 as a boost) and computed tomography–based planning. Over the first 18 months, we implemented several targeted interventions into our HDR workflow to improve efficiency. To evaluate the progress of the HDR program, we used linear mixed-effects models to compare LDR and HDR dosimetry and identify changes in the implant procedure and treatment planning durations over time.

Results

The study cohort consisted of 122 patients (51 who received LDR and 71 HDR). The mean D90 was similar between patients who received LDR and HDR (P = .28). HDR mean V100 and V95 were higher (P < .0001), but mean V200 and V150 were lower (P < .0001). HDR rectum V100 and D1cc were lower (P < .0001). The HDR mean for the implant procedure duration was shorter (54 vs 60 minutes; P = .02). The HDR mean for the treatment planning duration dramatically improved with the implementation of targeted workflow interventions (3.7 hours for the first quartile to 2.0 hours for the final quartile; P < .0001).

Conclusions

We successfully developed a prostate HDR brachytherapy program at our institution with comparable dosimetry to our historic LDR patients. We identified several targeted interventions that improved the efficiency of treatment planning. Our experience and workflow interventions may help other institutions develop similar HDR programs.

Phase 1-2 Study of Stereotactic Ablative Radiotherapy Including Regional Lymph Node Irradiation in Patients With High-Risk Prostate Cancer (SATURN): Early Toxicity and Quality of Life

PURPOSE

Five-fraction stereotactic ablative radiation therapy appears to be gaining popularity in treatment of prostate cancer, but it has not been extensively tested in the context of pelvic radiation. The objective of this prospective prostate and pelvic SABR study is to report the acute toxicity, late toxicity, and quality of life (QoL) after study completion.

METHODS AND MATERIALS

A phase 1/2 study was conducted for patients with high-risk prostate cancer. Radiation therapy was planned to deliver 25 Gy to pelvis and seminal vesicles (SV) and a simultaneous integrated boost (SIB) of up to 40 Gy to the prostate in 5 fractions, weekly, over 29 days. Androgen deprivation therapy was used for 12 to 18 months. Common Terminology Criteria for Adverse Events version 3.0 was used to assess worst acute and late toxicities. QoL data was captured using the Expanded Prostate Cancer Index Composite questionnaire (EPIC).

RESULTS

Thirty patients completed the planned treatment with a median follow-up of 25.7 months (range, 18.5-30.7 months). The following "worst" acute and late toxicities were observed: grade 2 genitourinary toxicity, 46.7% and 52%, respectively; grade 2 gastrointestinal toxicity, 3.3% and 32%, respectively. No grade 3 or higher toxicities were noted. Mean (95% confidence interval) EPIC urinary QoL scores were 86.6 (81.9-91.3), 87.1 (81.4-92.6), and 87.9 (80.1-95.7) at baseline, 3 months and 24 months; bowel scores were 94.1 (91.3-97.0), 93.2 (89.1-97.2), and 92.4 (87.7- 97.1), respectively.

CONCLUSIONS

This gantry-based novel fractionation schedule incorporating pelvic radiation for high-risk prostate cancer in combination with androgen deprivation therapy is feasible and well tolerated.

Hypofractionated external beam radiation therapy in combination with HDR boost for localized prostate cancer: patient reported quality of life outcomes

Purpose

There is limited data to support the use of hypofractionated external beam radiation (HypoF) in combination with high-dose-rate brachytherapy (HDR). We report our quality of life (QOL) outcomes when treating intermediate and high-risk prostate cancer patients with external beam radiation (EBRT) plus HDR.

Material and methods

The charts of 54 patients with localized adenocarcinoma of the prostate treated with standard fractionation (SF) or HypoF EBRT plus HDR boost at a single institution between 2012 and 2015 were reviewed. All patients completed the American Urological Association Symptom Score (AUASS) and Expanded Prostate Index for Prostate Cancer - Clinical Practice (EPIC-CP) quality of life assessments prior to treatment and completed at least one follow-up survey. Linear mixed models were performed to test for significant changes and differences in each outcome over time.

Results

There was no significant difference in AUA score (p = 0.98), incontinence (urge) and urinary irritation/obstruction scores (p = 0.81 and p = 0.62, respectively), and bowel QOL (p = 0.97) between the two dosing groups over time or at any discrete time point. For both groups, AUA scores peaked at 0-2 months before improving. Likewise, sexual function, vitality score, and QOL scores were also not significantly different between the dose groups over time (p = 0.59, p = 0.37, and p = 0.71, respectively). All QOL categories, except sexual function, trended toward baseline with increasing time from intervention.

Conclusions

Our study suggests HypoF EBRT can be delivered in combination with HDR for patients with ntermediate-risk and high-risk adenocarcinoma of the prostate without increasing toxicity compared to SF with an HDR boost.

Randomised Phase II Feasibility Trial of Image-guided External Beam Radiotherapy With or Without High Dose Rate Brachytherapy Boost in Men with Intermediate-risk Prostate Cancer (CCTG PR15/ NCT01982786)

AIMS

We conducted a multicentre feasibility study to assess the ability to randomise patients between image-guided radiotherapy (IGRT) and IGRT + high dose rate (HDR) brachytherapy boost and to adhere to appropriate radiation quality assurance standards.

MATERIALS AND METHODS

The primary end point was to determine the ability to randomise 60 patients over an 18 month period. Arm 1 (IGRT) patients received 78 Gy in 39 fractions or 60 Gy in 20 fractions (physician's preference), whereas arm 2 (IGRT + HDR) received 37.5 Gy in 15 fractions with HDR boost of 15 Gy. The secondary end points included >grade 3 acute genitourinary and gastrointestinal toxicity, using Common Terminology Criteria for Adverse Events version 4.0 at 3 months, validation of a prospectively defined radiation oncology quality assurance to assess treatment compliance. All analyses were descriptive; no formal comparisons between treatment arms were carried out.

RESULTS

Between April 2014 and September 2015, 57 National Comprehensive Cancer Network (NCCN)-defined intermediate-risk prostate cancer patients were randomised between IGRT alone (arm 1; n = 29) and IGRT plus HDR brachytherapy boost (arm 2; n = 28). Overall, 93% received the treatment as randomised. There were four patients (one on IGRT arm 1 and three patients on the IGRT + HDR arm 2) who were treated differently from randomisation assignment. For the 29 patients receiving IGRT (arm 1), there were 14 cases reported with minor deviations and three with major deviations. For patients on IGRT + HDR (arm 2), there were 18 cases reported with minor deviations and two with major deviations. At 3 months in the IGRT group (arm 1), one patient reported grade 3 diarrhoea, whereas in the IGRT + HDR group (arm 2), two patients reported grade 3 haematuria. No other gastrointestinal and genitourinary toxicities were reported.

CONCLUSION

The pilot study showed the feasibility of randomisation between treatment with IGRT alone versus IGRT + HDR boost. Treatment compliance was good, including adherence to quality assurance standards.

High dose-rate brachytherapy in the treatment of prostate cancer

High dose-rate (HDR) brachytherapy involves delivery of a high dose of radiation to the cancer with great sparing of surrounding organs at risk. Prostate cancer is thought to be particularly sensitive to radiation delivered at high dose-rate or at high dose per fraction. The rapid delivery and high conformality of dose results in lower toxicity than that seen with low dose-rate (LDR) implants. HDR combined with external beam radiotherapy results in higher cancer control rate than external beam only, and should be offered to eligible high and intermediate risk patients. While a variety of dose and fractionations have been used, a single 15 Gy HDR combined with 40-50 Gy external beam radiotherapy results in a disease-free survival of over 90% for intermediate risk and 80% for high risk. HDR monotherapy in two or more fractions (e.g., 27 Gy in 2 fractions or 34.5 Gy in 3) is emerging as a viable alternative to LDR brachytherapy for low and low-intermediate risk patients, and has less toxicity. The role of single fraction monotherapy to a dose of 19-20 Gy is evolving, with some conflicting data to date. HDR should also be considered as a salvage approach for recurrent disease following previous external beam radiotherapy. A particular advantage of HDR in this setting is the ease of delivering focal treatments, which combined with modern imaging allows focal dose escalation with minimal toxicity. Trans-rectal ultrasound (TRUS) based planning is replacing CT-based planning as the technique of choice as it minimizes or eliminates the need to move the patient between insertion, planning and treatment delivery, thus ensuring high accuracy and reproducibility of treatment.

Patient-reported outcomes after treatment for clinically localized prostate cancer: A systematic review and meta-analysis

BACKGROUND

The aim of this systematic review is to assess the impact of primary treatments with curative intention in patients with localized prostate cancer, measured with Patient-Reported Outcomes (PROs), and to examine differences among modalities within treatments.

METHODS

We conducted a systematic literature search for January 2005-March 2017 following PRISMA guidelines, including longitudinal studies measuring disease-specific PROs in localized prostate cancer patients with a follow-up from pre- to post-treatment (≥1 year). Two reviewers independently extracted data and assessed risk of bias. The study is registered in PROSPERO: CRD42015019747.

RESULTS

Of 148 identified studies, 60 were included in the meta-analyses. At the 1st year, radical prostatectomy patients showed small urinary irritative-obstructive improvement (0.37SD 95%CI 0.30, 0.45), but large deterioration for sexual function and incontinence with high heterogeneity (I² = 77% and 93%). Moderate worsening in external radiotherapy patients for sexual function (-0.46SD 95%CI -0.55, -0.36), small urinary incontinence (-0.16SD 95%CI -0.23, -0.09) and bowel impairment (-0.31SD 95%CI -0.39, -0.23). Brachytherapy patients presented small deterioration in urinary incontinence (-0.29SD 95%CI -0.39, -0.19), irritative obstructive symptoms (-0.35SD 95%CI -0.47, -0.23), sexual function (-0.12SD 95%CI -0.24, -0.002), and bowel bother (-0.27SD 95%CI -0.42, -0.11). These patterns persisted up to the 5th year. High-intensity focused ultrasound and active surveillance only have results at 1st year, showing no statistically significant worsening.

CONCLUSIONS

No remarkable differences in PRO appeared between modalities within each treatment. Nowadays, available evidence supports brachytherapy as possible alternative to radical prostatectomy for patients seeking an attempted curative treatment limiting the risk for urinary incontinence and sexual dysfunction.

Dose escalation for prostate stereotactic ablative radiotherapy (SABR): Late outcomes from two prospective clinical trials

PURPOSE

Optimal prostate SABR dose-fractionation is unknown. This study compares long-term outcomes from two prospective trials.

METHODS

Study1 patients had low-risk PCa and received 35 Gy/5. Study2 patients had low/intermediate-risk PCa and received 40 Gy/5. Biochemical failure (BF) was defined as nadir + 2.

RESULTS

114 patients were included (study1, n = 84; study2, n = 30). Median follow-up was 9.6 years and 6.9 years. Median nPSA was 0.4 and 0.1 ng/ml. Nine patients had BF (8 in study1, 1 in study2); two were managed with ADT and four had local salvage. The BF rate was 2.5% and 12.8% at 5 and 10 years for study1 and 3.3% at 5 years for study 2. BF probability was 0% if PSA <0.4 at 4 years, and 20.5% at 10 years if PSA ≥0.4 (p = 0.02). Nine patients died, none of PCa. No patient has metastases or castrate-resistance. At 10 years, OS and CSS were 90.4% (p = 0.25) and 100%.

CONCLUSIONS

Dose-escalated prostate SABR was associated with lower nPSAs but no difference in BF, OS, CSS or MFS. PSA <0.4 at 4 years was a predictor of biochemical control. Half of patients with BF were successfully salvaged. Given that this is a favorable-risk cohort, longer follow-up will be needed to see if the lower nPSA translates into lower BF rates.

Dosimetric impact of inter-observer catheter reconstruction variability in ultrasound-based high-dose-rate prostate brachytherapy

PURPOSE

To investigate the dosimetric impact of interobserver catheter reconstruction variability in transrectal ultrasound-guided prostate high-dose-rate (HDR) brachytherapy.

METHODS AND MATERIALS

Twenty consecutive patients with intermediate- or high-risk prostate cancer were treated with a single, 15-Gy HDR brachytherapy boost as part of this study. The treated plan was used as the study reference plan (P_R). Three expert treatment planners (observers) manually reconstructed the catheter paths on the static three-dimensional transrectal ultrasound images, and new plans were generated from the updated positions (P_OBS); subsequently, the dwell time and positions from the P_OBS plans were superimposed on the P_R catheter paths to evaluate the dosimetric effect of the interobserver variations (P_EVAL). Plans from each group were stratified by observer and by number of catheters (12 or 16) and then compared using a one-way Kruskal-Wallis H test with post hoc Mann-Whitney U tests reserved for significant variations (α = 0.05).

RESULTS

Greater than 98.9% of catheter reconstruction variations were <3 mm. When stratified by observer, there was a significant decrease (p << 0.05) in planning target volume (PTV) V_100% and increases in the urethral D_max between the P_OBS plans propagated to the P_R catheter paths and dosimetry evaluated and P_R plans only. Stratification of plans by catheter number showed nonclinically significant decreases in PTV V_100%, and D_90% and increases in urethral D_max for the 12-catheter plans.

CONCLUSIONS

Limiting interobserver variability, and its effects on prostate HDR brachytherapy plan quality, is critical to achieving good dosimetric outcomes; small variations in catheter reconstruction may translate to inadequate PTV coverage, excessive urethral dose, or both.

Dose accumulation of multiple high dose rate prostate brachytherapy treatments in two commercially available image registration systems

PURPOSE

The purpose of this study was to assess whether deformable image registration (DIR) is required for dose accumulation of multiple high dose rate prostate brachytherapy (HDRPBT) plans treated with the same catheter pattern on two different CT datasets.

METHOD

DIR was applied to 20 HDRPBT patients' planning CT images who received two treatment fractions on sequential days, on two different CT datasets, with the same implant. Quality of DIR in Velocity and MIM image registration systems was assessed by calculating the Dice Similarity Coefficient (DSC) and mean distance to agreement (MDA) for the prostate, urethra and rectum contours. Accumulated doses from each system were then calculated using the same DIR technique and dose volume histogram (DVH) parameters compared to manual addition with no DIR.

RESULTS

The average DSC was found to be 0.83 (Velocity) and 0.84 (MIM), 0.80 (Velocity) and 0.80 (MIM), 0.80 (Velocity) and 0.81 (MIM), for the prostate, rectum and urethra contours, respectively. The average difference in calculated DVH parameters between the two systems using dose accumulation was less than 1%, and there was no statistically significant difference found between deformably accumulated doses in the two systems versus manual DVH addition with no DIR.

CONCLUSION

Contour propagation using DIR in velocity and MIM was shown to be at least equivalent to inter-observer contouring variability on CT. The results also indicate that dose accumulation through manual addition of DVH parameters may be sufficient for HDRPBT treatments treated with the same catheter pattern on two different CT datasets.

[Therapeutic innovations in radiation oncology for localized prostate cancer]

Intensity-modulated radiation therapy, image-guided radiation therapy with fiducial markers and prostate brachytherapy allow the delivery of dose escalation for localized prostate cancer with very low rates of long-term toxicity and sequelae. Nowadays, modern radiotherapy techniques make it possible to shorten treatment time with hypofractionation, to better protect surrounding healthy tissues and to escalate the dose even further. Advances in radiotherapy are closely linked to advances in magnetic resonance imaging (MRI) and/or PET imaging. Functional imaging makes it possible to deliver personalised pelvic nodal radiotherapy, targeting the nodal areas at higher risk of microscopic involvement. In patients with an index lesion at baseline or at failure, MR-based focal therapy or focal dose escalation with brachytherapy or stereotactic body radiation therapy is also currently investigated. MR-based adaptive radiotherapy, which makes it possible to track prostate shifts during radiation delivery, is another step forward in the integration of MR imaging in radiation delivery.

High-dose-rate brachytherapy boost for prostate cancer: Comparison of three different fractionation schemes

PURPOSE

Dose escalation for prostate cancer can be achieved with a combination of external beam radiotherapy (EBRT) and brachytherapy (BT) boost to increase local control. For high-dose-rate (HDR)-BT, optimal fractionation remains under debate. The objective was to assess the clinical outcome of three schemes of HDR-BT boost.

METHODS AND MATERIALS

Retrospective single institution data collection was performed. Patients received 46 Gy EBRT then an HDR-BT boost: 3 × 6 Gy, 2 × 9 Gy, or 1 × 14 Gy. HDR needles were placed under general anesthesia with endorectal ultrasonography guidance. CT-scan and treatment were performed postoperatively.

RESULTS

Between 2009 and 2012, 159 patients were included. Nine patients (5.7%) were low, 32 (20.1%) intermediate, and 118 (74.2%) high risk (D'Amico classification) without significant difference between the three BT schemes. With a median followup of 61 months, 5-year biochemical relapse-free survival, 5-year local relapse-free survival, 5-year metastases-free survival, and 5-year overall survival rates were 86.6% (SE 2.7%), 98.3% (SE 1%), 95.3% (SE 1%), and 96.5% (SE 1.5%), respectively, with no significant difference between the BT schemes. The rates of acute ≥ G2 genitourinary and ≥G2 gastrointestinal toxicities were 11.3% and 6.3%, respectively (p = NS). The rates of late genitourinary ≥ G2 and gastrointestinal ≥ G2 toxicities (at last followup) were 9.4% and 0.6% with, respectively, 0.6% and 0% of G4 (p = NS).

CONCLUSIONS

Hypofractionation up to a single-fraction HDR-BT boost for prostate cancer yields similar results in terms of biochemical control and late toxicity compared with two or three-fraction schemes. Single fraction HDR-BT appears acceptable for boosting prostate cancer after definitive EBRT.

The evolution of brachytherapy for prostate cancer

Brachytherapy (BT), using low-dose-rate (LDR) permanent seed implantation or high-dose-rate (HDR) temporary source implantation, is an acceptable treatment option for select patients with prostate cancer of any risk group. The benefits of HDR-BT over LDR-BT include the ability to use the same source for other cancers, lower operator dependence, and - typically - fewer acute irritative symptoms. By contrast, the benefits of LDR-BT include more favourable scheduling logistics, lower initial capital equipment costs, no need for a shielded room, completion in a single implant, and more robust data from clinical trials. Prospective reports comparing HDR-BT and LDR-BT to each other or to other treatment options (such as external beam radiotherapy (EBRT) or surgery) suggest similar outcomes. The 5-year freedom from biochemical failure rates for patients with low-risk, intermediate-risk, and high-risk disease are >85%, 69-97%, and 63-80%, respectively. Brachytherapy with EBRT (versus brachytherapy alone) is an appropriate approach in select patients with intermediate-risk and high-risk disease. The 10-year rates of overall survival, distant metastasis, and cancer-specific mortality are >85%, <10%, and <5%, respectively. Grade 3-4 toxicities associated with HDR-BT and LDR-BT are rare, at <4% in most series, and quality of life is improved in patients who receive brachytherapy compared with those who undergo surgery.

Brachytherapy for Patients With Prostate Cancer: American Society of Clinical Oncology/Cancer Care Ontario Joint Guideline Update

Purpose

To jointly update the Cancer Care Ontario guideline on brachytherapy for patients with prostate cancer to account for new evidence.

Methods

An Update Panel conducted a targeted systematic literature review and identified more recent randomized controlled trials comparing dose-escalated external beam radiation therapy (EBRT) with brachytherapy in men with prostate cancer.

Results

Five randomized controlled trials provided the evidence for this update.

Recommendations

For patients with low-risk prostate cancer who require or choose active treatment, low–dose rate brachytherapy (LDR) alone, EBRT alone, and/or radical prostatectomy (RP) should be offered to eligible patients. For patients with intermediate-risk prostate cancer choosing EBRT with or without androgen-deprivation therapy, brachytherapy boost (LDR or high–dose rate [HDR]) should be offered to eligible patients. For low-intermediate risk prostate cancer (Gleason 7, prostate-specific antigen < 10 ng/mL or Gleason 6, prostate-specific antigen, 10 to 20 ng/mL), LDR brachytherapy alone may be offered as monotherapy. For patients with high-risk prostate cancer receiving EBRT and androgen-deprivation therapy, brachytherapy boost (LDR or HDR) should be offered to eligible patients. Iodine-125 and palladium-103 are each reasonable isotope options for patients receiving LDR brachytherapy; no recommendation can be made for or against using cesium-131 or HDR monotherapy. Patients should be encouraged to participate in clinical trials to test novel or targeted approaches to this disease. Additional information is available at www.asco.org/Brachytherapy-guideline and www.asco.org/guidelineswiki .

High dose rate brachytherapy for prostate cancer: Standard of care and future direction

High dose rate brachytherapy is a highly conformal method of radiation dose escalation for prostate cancer and one of several treatment options for men with localised disease. The large doses per fraction exploit the low alpha/beta ratio of prostate cancer cells so that biological radiation dose delivered is substantially greater than that achieved with conventional external beam delivery. This review article presents contemporary data on the rationale for high dose rate brachytherapy including treatment technique and future directions.

Dose-escalation of five-fraction SABR in prostate cancer: Toxicity comparison of two prospective trials

PURPOSE

To compare biochemical outcome and toxicities of two prospective 5-fraction stereotactic ablative radiotherapy (SABR) studies in prostate cancer.

MATERIALS AND METHODS

84 patients in pHART3 received 35 Gy, 30 patients in pHART6 received 40 Gy in 5-fractions to the prostate alone, once weekly. 4mm and 5mm PTV margins were used, respectively. Biochemical outcome, acute, late and cumulative genitourinary (GU)/gastrointestinal (GI) toxicities were compared.

RESULTS

Median follow-up was 74 and 36 months, respectively. Median prostate specific antigen nadir was 0.4 ng/ml and 0.3 ng/ml. 2-, 4- and 6-year biochemical relapse-free survival (bRFS-2+nadir) was 100%, 98.7% and 95.9% in pHART3; 100%, 100% and not reached in pHART6 (p=0.91). There was one acute grade 3 GU (retention) and late grade 4 GI (fistula) toxicity in pHART3, none in pHART6. One patient in each study had persisting grade 2+ toxicity at the last follow-up. pHART6 patients had a greater grade 2+ cumulative GU (5% versus 24.2%) and GI (7.6% versus 26.2%) toxicities.

CONCLUSIONS

Patients receiving dose-escalated SABR had slightly lower PSA nadir and similar bRFS, longer follow-up is needed to better estimate biochemical outcomes. There was a greater risk of grade 2 toxicity in pHART6 but not grade 3+ toxicities. Persisting toxicity at the last follow-up is similar.

Clinical trials of stereotactic ablative radiotherapy for prostate cancer: updates and future direction

Stereotactic body radiotherapy, also known as stereotactic ablative body radiotherapy (SABR), is an emerging treatment option for lung, prostate, liver and other tumors. Key factors in SABR are delivery of a high-dose radiation per fraction, proper patient positioning and target localization. Our review details the various radiotherapy techniques, dose fractionation schedules and toxicities for prostate SABR. Ongoing Phase II/III SABR studies across various risk groups have been included. It also discusses the role of conscientious focal dose escalation of the dominant intraprostatic nodule, integrating multiparametric MRI into radiotherapy protocols and finally cost-effectiveness of SABR.

The curative management of synchronous rectal and prostate cancer

OBJECTIVE

Neoadjuvant "long-course" chemoradiation is considered a standard of care in locally advanced rectal cancer. In addition to prostatectomy, external beam radiotherapy and brachytherapy with or without androgen suppression (AS) are well established in prostate cancer management. A retrospective review of ten cases was completed to explore the feasibility and safety of applying these standards in patients with dual pathology. To our knowledge, this is the largest case series of synchronous rectal and prostate cancers treated with curative intent.

METHODS

Eligible patients had synchronous histologically proven locally advanced rectal cancer (defined as cT3-4Nx; cTxN1-2) and non-metastatic prostate cancer (pelvic nodal disease permissible). Curative treatment was delivered to both sites simultaneously. Follow-up was as per institutional guidelines. Acute and late toxicities were reviewed, and a literature search performed.

RESULTS

Pelvic external beam radiotherapy (RT) 45-50.4 Gy was delivered concurrent with 5-fluorouracil (5FU). Prostate total dose ranged from 70.0 to 79.2 Gy. No acute toxicities occurred, excluding AS-induced erectile dysfunction. Nine patients proceeded to surgery, and one was managed expectantly. Three relapsed with metastatic colorectal cancer, two with metastatic prostate cancer. Five patients have no evidence of recurrence, and four remain alive with metastatic disease. With a median follow-up of 2.2 years (range 1.2-6.3 years), two significant late toxicities occurred; G3 proctitis in a patient receiving palliative bevacizumab and a G3 anastomotic stricture precluding stoma reversal.

CONCLUSION

Patients proceeding to synchronous radical treatment of both primary sites should receive 45-50.4 Gy pelvic RT with infusional 5FU. Prostate dose escalation should be given with due consideration to the potential impact of prostate cancer on patient survival, as increasing dose may result in significant late morbidity. Review of published series explores the possibility of prostate brachytherapy as an alternative method of boost delivery. Frequent use of bevacizumab in metastatic rectal cancer may compound late rectal morbidity in this cohort.

ADVANCES IN KNOWLEDGE

To our knowledge, this is the largest case series of synchronous rectal and prostate cancers treated with curative intent. This article contributes to the understanding of how best to approach definitive treatment in these patients.

Comparison of focal boost high dose rate prostate brachytherapy optimisation methods

For HDR prostate brachytherapy treatments of 15 Gy to the whole gland plus focal boost, optimisation to either tumour plus margin (F-PTV) or involved sectors was compared. For 15 patients median F-PTV D90 and V150 were 21.0 Gy and 77.2% for F-PTV optimisation and 19.8 Gy and 75.6% for sector optimisation.

Review of advanced catheter technologies in radiation oncology brachytherapy procedures

The development of new catheter and applicator technologies in recent years has significantly improved treatment accuracy, efficiency, and outcomes in brachytherapy. In this paper, we review these advances, focusing on the performance of catheter imaging and reconstruction techniques in brachytherapy procedures using magnetic resonance images and electromagnetic tracking. The accuracy of catheter reconstruction, imaging artifacts, and other notable properties of plastic and titanium applicators in gynecologic treatments are reviewed. The accuracy, noise performance, and limitations of electromagnetic tracking for catheter reconstruction are discussed. Several newly developed applicators for accelerated partial breast irradiation and gynecologic treatments are also reviewed. New hypofractionated high dose rate treatment schemes in prostate cancer and accelerated partial breast irradiation are presented.