Brachytherapy boost for prostate cancer: Trends in care and survival outcomes

Recent trends in the incidence of early-onset prostate cancer

Early-onset prostate cancer (EOPC) is relatively uncommon. It is unclear if the incidence of EOPC is evolving. Utilizing data from the SEER database from 2000 to 2020, the study identified prostate cancer cases in men under 55 years, focusing on trends in annual age-adjusted incidence rates (AAIR), stage at presentation, race/ethnicity, and local treatment patterns. The study encompassed 93 071 cases of EOPC, with the median age at diagnosis being 51 years. From 2000 to 2007, the AAIR of EOPC experienced a wave-like increase from 6.9 to 8.3 per 100 000 people. It then sharply declined to 5.4 by 2014, followed by 6 years of stability, and by 2020 it had dropped to its lowest point of 4.5. The trend observed across different racial groups was consistent with the overall pattern, where non-Hispanic Black patients consistently exhibited the highest incidence and the least reduction rate (annual percent change, -1.0; 95% confidence interval, -1.8 to -0.2; P < 0.05). Stage II was the most commonly diagnosed, although its AAIR declined from 4.9 to 1.2 per 100 000 people. From 2010 through 2020, the proportion of receiving prostatectomy decreased from 63.0 to 43.6%. The declining rates of EOPC across diverse racial groups emphasize the critical need for focused research and interventions. Specifically, there is an urgent call to establish a tailored screening protocol for prostate cancer targeting Black youth.

A Randomized Trial Comparing Quality of Life After Low-Dose Rate or High-Dose Rate Prostate Brachytherapy Boost With Pelvic External Beam Radiation Therapy

PURPOSE

To compare health-related quality of life (QoL) in urinary, bowel, and sexual domains after combined external beam radiation therapy (EBRT) and either low-dose rate (LDR) or high-dose rate (HDR) prostate brachytherapy (BT).

METHODS AND MATERIALS

Eligible men with intermediate or high-risk prostate cancer treated with combined pelvic EBRT and BT were randomly assigned to either HDR (15 Gy) or LDR (110 Gy) boost. International Prostate Symptom Score, Index of Erectile Function, and Expanded Prostate Cancer Composite were collected at baseline, 1, 3, 6, and 12 months, every 6 months to 3 years and then annually along with prostate-specific antigen/testosterone. Fisher's exact test compared categorical variables and the Mann-Whitney U test Expanded Prostate Cancer Index Composite (EPIC) domain scores.

RESULTS

From January 2014 to December 2019, a random number generator assigned 195 men: 108 to HDR and 87 to LDR. Median age was 71 years. Risk group was high in 57% and unfavorable intermediate in 43%. Androgen deprivation (used in 74%) began with 3 months neoadjuvant and continued for median 12 months. Baseline EPIC scores were similar for the LDR/HDR cohorts: 89 and 88 respectively for Genito-urinary; 92 and 93 for Gastro-intestinal. EPIC urinary scores decreased at 1 month for HDR but recovered promptly to a steady state by 6 months. LDR scores reached a nadir at 3 months with slow recovery to 18 months, after which urinary QoL was similar for HDR and LDR. Bowel QOL scores fell in both cohorts reaching respective nadirs at 12 months. HDR patients recovered close to baseline and maintained higher scores than LDR patients to 5 years. The decline for LDR patients remained more than the minimum clinically important difference out to 5 years.

CONCLUSIONS

The patient experience for combined EBRT and prostate BT is improved with HDR BT. Urinary QoL improves over time to be equivalent between the 2 modalities after 18 months, but LDR patients report lasting bowel symptoms.

A Systematic Review of the Efficacy and Toxicity of Brachytherapy Boost Combined with External Beam Radiotherapy for Nonmetastatic Prostate Cancer

CONTEXT

The optimum use of brachytherapy (BT) combined with external beam radiotherapy (EBRT) for localised/locally advanced prostate cancer (PCa) remains uncertain.

OBJECTIVE

To perform a systematic review to determine the benefits and harms of EBRT-BT.

EVIDENCE ACQUISITION

Ovid MEDLINE, Embase, and EBM Reviews-Cochrane Central Register of Controlled Trials databases were systematically searched for studies published between January 1, 2000 and June 7, 2022, according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) statement. Eligible studies compared low- or high-dose-rate EBRT-BT against EBRT ± androgen deprivation therapy (ADT) and/or radical prostatectomy (RP) ± postoperative radiotherapy (RP ± EBRT). The main outcomes were biochemical progression-free survival (bPFS), severe late genitourinary (GU)/gastrointestinal toxicity, metastasis-free survival (MFS), cancer-specific survival (CSS), and overall survival (OS), at/beyond 5 yr. Risk of bias was assessed and confounding assessment was performed. A meta-analysis was performed for randomised controlled trials (RCTs).

EVIDENCE SYNTHESIS

Seventy-three studies were included (two RCTs, seven prospective studies, and 64 retrospective studies). Most studies included participants with intermediate-or high-risk PCa. Most studies, including both RCTs, used ADT with EBRT-BT. Generally, EBRT-BT was associated with improved bPFS compared with EBRT, but similar MFS, CSS, and OS. A meta-analysis of the two RCTs showed superior bPFS with EBRT-BT (estimated fixed-effect hazard ratio [HR] 0.54 [95% confidence interval {CI} 0.40-0.72], p < 0.001), with absolute improvements in bPFS at 5-6 yr of 4.9-16%. However, no difference was seen for MFS (HR 0.84 [95% CI 0.53-1.28], p = 0.4) or OS (HR 0.87 [95% CI 0.63-1.19], p = 0.4). Fewer studies examined RP ± EBRT. There is an increased risk of severe late GU toxicity, especially with low-dose-rate EBRT-BT, with some evidence of increased prevalence of severe GU toxicity at 5-6 yr of 6.4-7% across the two RCTs.

CONCLUSIONS

EBRT-BT can be considered for unfavourable intermediate/high-risk localised/locally advanced PCa in patients with good urinary function, although the strength of this recommendation based on the European Association of Urology guideline methodology is weak given that it is based on improvements in biochemical control.

PATIENT SUMMARY

We found good evidence that radiotherapy combined with brachytherapy keeps prostate cancer controlled for longer, but it could lead to worse urinary side effects than radiotherapy without brachytherapy, and its impact on cancer spread and patient survival is less clear.

Health Services Research in Brachytherapy: Current Understanding and Future Challenges

Brachytherapy is an integral component of cancer care. Widespread concerns have been expressed though about the need for greater brachytherapy availability across many jurisdictions. Yet, health services research in brachytherapy has lagged behind that in external beam radiotherapy. Optimal brachytherapy utilisation, to help inform expected demand, have not been defined beyond the New South Wales region in Australia, with few studies having reported observed brachytherapy utilisation. There is also a relative lack of robust cost and cost-effectiveness studies, making investment decisions in brachytherapy even more uncertain and challenging to justify, despite its key role in cancer control. As the range of indications for brachytherapy expands, providing organ/function preservation for a wider range of diagnoses, there is an urgent need to redress this balance. By outlining the work undertaken in this area to date, we highlight its importance and explore where further study is required.

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.

The value of brachytherapy in the age of advanced external beam radiotherapy: a review of the literature in terms of dosimetry

Brachytherapy (BT) has long been used for successful treatment of various tumour entities, including prostate, breast and gynaecological cancer. However, particularly due to advances in modern external beam techniques such as intensity-modulated radiotherapy (IMRT), volume modulated arc therapy (VMAT) and stereotactic body radiotherapy (SBRT), there are concerns about its future. Based on a comprehensive literature review, this article aims to summarize the role of BT in cancer treatment and highlight its particular dosimetric advantages. The authors conclude that image-guided BT supported by inverse dose planning will successfully compete with high-tech EBRT in the future and continue to serve as a valuable modality for cancer treatment.

Utilization of brachytherapy in Quebec, Canada

BACKGROUND AND PURPOSE

Despite the excellent clinical outcomes from brachytherapy treatments compared with other modalities and the low associated costs, there have been reports of a decline in utilization of brachytherapy. The aim of this study was to investigate in detail the trend in utilization of brachytherapy in the province of Québec, Canada, from 2011 to 2019.

MATERIALS AND METHODS

All radiotherapy clinics in the province of Quebec, and among these the clinics that provide brachytherapy treatments, were identified. This observational retrospective cohort study involved analysis of data compiled by the Ministère de la Santé et des Services Sociaux du Québec for the period of 2011 to end of 2019 on all brachytherapy procedures performed in the province of Quebec. Time series graphs were used to describe the number of high dose rate (HDR) and low dose rate (LDR) brachytherapy treatments during the studied time period. Statistical analysis was conducted using R statistical software.

RESULTS

Between 2011 and 2019, 12 hospitals in the province of Québec provided radiotherapy treatments, and all of them offered brachytherapy services. The median annual number of brachytherapy sessions was 4413 (range 3930-4829). HDR brachytherapy represented over 90% of all brachytherapy treatments throughout the study period. Significant changes over time were observed in the number of treatments: at least 5% change was seen only for the two most common subtypes of brachytherapy, HDR interstitial and HDR intracavitary, with an increase of 9.6% and a decrease of 9.2%, respectively. The use of other subtypes of brachytherapy (HDR-plesiotherapy, LDR-interstitial, LDR-intracavitary, LDR-eye plaque) was stable between 2011 and 2019, with ≤ 2.5% variation.

CONCLUSION

This study demonstrates an overall steady use of brachytherapy between 2011 and 2019 in Quebec. Brachytherapy offers numerous advantages for the treatment of diverse cancer sites. Although more sophisticated external beam radiotherapy treatments have emerged in the last decades, the precision and cost-effectiveness of brachytherapy remain unbeaten. To ensure the continued use and availability of brachytherapy, governments must put in place policies and regulations to that effect. Training and exposure of future health care professionals to brachytherapy within Quebec and Canada is essential to provide all patients the same access to this life saving modality.

PSA: Declining utilization of prostate brachytherapy

PURPOSE

To analyze rates of brachytherapy use for prostate cancer over time and evaluate patient characteristics, demographics and factors predictive for its utilization.

METHODS

Data was retrospectively analyzed from the National Cancer Database (NCDB) for patients with localized prostate cancer treated between 2010 and 2015. Patients were included if they had biopsy confirmed localized adenocarcinoma of the prostate, were treated with radiation as definitive local therapy, and were at least 18 years old. Utilization rates of external beam radiation (EBRT), brachytherapy (BT) and combination (EBRT + BT) were evaluated over time. Univariable (UVA) and backwards elimination multivariable (MVA) analysis were performed to determine characteristics predictive for brachytherapy use.

RESULTS

We analyzed 178,837 patients with localized adenocarcinoma of the prostate treated between 2010 and 2015 with radiation therapy. During this period, the use of EBRT increased from 67% to 78%, BT (both monotherapy and combination with EBRT) decreased from 33% to 22%, BT monotherapy decreased from 25% to 16% and EBRT + BT decreased from 8% to 6%. Age >70, government funded insurance or lack of insurance, intermediate or high-risk disease and treatment at an academic center were associated with significantly lower utilization of brachytherapy (all p <0.001), while higher median zip code income was associated with increased use (p = 0.02). On multivariable analysis patients who were younger, had private insurance, were lower NCCN risk category and treated in non-academic cancer centers, had a higher rate of brachytherapy utilization. Notably, on both UVA and MVA brachytherapy practice decreased with increasing year of diagnosis (OR 0.881, 95% CI 0.853-0.910, p <0.001).

CONCLUSION

Rates of brachytherapy utilization for the treatment of prostate cancer continue to decrease over time. Treatment at an academic center was associated with reduced likelihood of brachytherapy use. This has significant implications for the training of future radiation oncology residents/fellows and direct consequences for both our patients and healthcare expenditure.

A primer on time-driven activity-based costing in brachytherapy

Emphasis on value-based healthcare has led to increasing use of time-driven activity-based costing (TDABC) across medical departments. When applied to brachytherapy, TDABC provides insight into differences in costs across various modes of therapy, the nuances that drive cost including institutional factors and involved personnel, and discrepancies in reimbursement which influence clinical practice. This is especially important with the new alternative payment model (APM) in radiation oncology which offers fixed reimbursement per 90-day episode of care. The TDABC model can thus be utilized to improve efficiency, optimize the role of ancillary staff in treatment planning and care delivery, and implement shorter fraction schedules when clinically appropriate to promote value-based care. Ultimately, application of this methodology could potentiate changes to practice and incentives to improve patient care. In this review, we discuss the utility and limitations of TDABC in the context of existing studies in brachytherapy which have utilized this methodology.

Outcomes with brachytherapy based dose escalation for gleason 8 versus 9-10 prostate cancer: An NCDB analysis

INTRODUCTION

The addition of brachytherapy (BT) in high risk prostate cancer is supported by Level 1 evidence. Whether all high risk patients benefit from BT to the same extent is unknown. The National Cancer Database (NCDB) was used to investigate overall survival (OS) differences between GS 8 and 9-10 treated with external beam radiation (EBRT) only or BT +/- EBRT.

MATERIALS AND METHODS

We included localized prostate adenocarcinoma definitively treated with radiation between 2004-2014. Patients were stratified into various radiation treatment groups: EBRT 7560 - 8640 cGy, EBRT 5940 - 7540 cGy, and BT +/- EBRT. All EBRT only and BT +/- EBRT patients received ADT. A multivariable Cox proportional hazard model was used to assess OS. Propensity score matching was used to account for differences between groups. Median survival was determined based on Kaplan-Meier survival curves.

RESULTS

30,698 patients were included. On multivariable analysis among GS 8 patients, BT was associated with improved OS compared to 7560 - 8640 cGy (HR-0.80 (95% CI 0.70-0.92, P = 0.002). In Gleason 9-10 BT did not result in improved OS compared to 7560 - 8640 cGy (HR- 0.91 (95% CI 0.79 - 1.05, P = 0.212). Results remained significant with propensity score matching and removing patients with medical comorbidities.

CONCLUSION

BT was associated with improved OS when compared to 7560 - 8640 cGy in GS 8, but not in Gleason 9-10 disease. This hypothesis generating study suggests there may be variable benefit with BT in high risk prostate cancer patients on OS. Future prospective studies are needed to investigate whether the benefit of BT is similar across all high risk prostate cancer patients.

Simulation of an HDR "Boost" with Stereotactic Proton versus Photon Therapy in Prostate Cancer: A Dosimetric Feasibility Study

Purpose/Objectives

To compare the dose escalation potential of stereotactic body proton therapy (SBPT) versus stereotactic body photon therapy (SBXT) using high-dose rate prostate brachytherapy (HDR-B) dose-prescription metrics.

Patients and Methods

Twenty-five patients previously treated with radiation for prostate cancer were identified and stratified by prostate size (≤ 50cc; n = 13, > 50cc; n = 12). Initial CT simulation scans were re-planned using SBXT and SBPT modalities using a prescription dose of 19Gy in 2 fractions. Target coverage goals were designed to mimic the dose distributions of HDR-B and maximized to the upper limit constraint for the rectum and urethra. Dosimetric parameters between SBPT and SBXT were compared using the signed-rank test and again after stratification for prostate size (≤ 50cm³ and >50cm³) using the Wilcoxon rank test.

Results

Prostate volume receiving 100% of the dose (V100) was significantly greater for SBXT (99%) versus SBPT (96%) (P ≤ 0.01), whereas the median V125 (82% vs. 73%, P < 0.01) and V200 (12% vs. 2%, P < 0.01) was significantly greater for SBPT compared to SBXT. Median V150 was 49% for both cohorts (P = 0.92). V125 and V200 were significantly correlated with prostate size. For prostates > 50cm³, V200 was significantly greater with SBPT compared to SBXT (14.5% vs. 1%, P = 0.005), but not for prostates 50cm³ (9% vs 4%, P = 0.11). Median dose to 2cm³ of the bladder neck was significantly lower with SBPT versus SBXT (9.6 Gy vs. 14 Gy, P < 0.01).

Conclusion

SBPT and SBXT can be used to simulate an HDR-B boost for locally advanced prostate cancer. SBPT demonstrated greater dose escalation potential than SBXT. These results are relevant for future trial design, particularly in patients with high risk prostate cancer who are not amenable to brachytherapy.

Brachytherapy boost (BT-boost) or stereotactic body radiation therapy boost (SBRT-boost) for high-risk prostate cancer (HR-PCa)

Systematic review for the treatment of high-risk prostate cancer (HR-PCa, D'Amico classification risk system) with external body radiation therapy (EBRT)+brachytherapy-boost (BT-boost) or with EBRT+stereotactic body RT-boost (SBRT-boost). In March 2020, 391 English citations on PubMed matched with search terms "high risk prostate cancer boost". Respectively 9 and 48 prospective and retrospective studies were on BT-boost and 7 retrospective studies were on SBRT-boost. Two SBRT-boost trials were prospective. Only one study (ASCENDE-RT) directly compared the gold standard treatment [dose-escalation (DE)-EBRT+androgen deprivation treatment (ADT)] versus EBRT+ADT+BT-boost. Biochemical control rates at 9 years were 83% in the experimental arm versus 63% in the standard arm. Cumulative incidence of late grade 3 urinary toxicity in the experimental arm and in the standard arm was respectively 18% and 5%. Two recent studies with HR-PCa (National Cancer Database) demonstrated better overall survival with BT-boost (low dose rate LDR or high dose rate HDR) compared with DE-EBRT. These recent findings demonstrate the superiority of EBRT+BT-boost+ADT versus DE-EBRT+ADT for HR-PCa. It seems that EBRT+BT-boost+ADT could now be considered as a gold standard treatment for HR-PCa. HDR or LDR are options. SBRT-boost represents an attractive alternative, but the absence of randomised trials does not allow us to conclude for HR-PCa. Prospective randomised international phase III trials or meta-analyses could improve the level of evidence of SBRT-boost for HR-PCa.

#ThisIsBrachytherapy: Increasing awareness of brachytherapy

PURPOSE

The use of brachytherapy continues to be a vital application of radiation oncology for various cancers. Despite this, there has been a decrease in the utilization of brachytherapy in many cancers. Social media in medicine facilitates engagement and advocacy. We launched a social media campaign to bring awareness of brachytherapy throughout the world with #ThisIsBrachytherapy hashtag on July 17, 2019.

METHODS AND MATERIALS

#ThisIsBrachytherapy hashtag was registered with Symplur Healthcare Hashtag Project. We collected total tweet counts, retweet counts, impression counts, geolocation, top 10 influencers, associated hashtags, associated words, and word sentiment score.

RESULTS

The campaign launched on July 17, 2019, had a total of 145 tweets on that day with 213,416 impressions. Twenty-seven accounts (45%) were identified as physicians. Top countries which tweeted, among those with information available, included the United States, United Kingdom, and Australia. Since July 17, 2019, there has been an increase in tweets using #ThisIsBrachytherapy, with 1990 total tweets with 1,999,248 impressions. Fifty-four percent (1030) of the tweets contained photos and 319 contained links. This was from 462 unique users. Word sentiment was overwhelmingly positive. Associated hashtags with #ThisIsBrachytherapy included most commonly #radonc, #brachytherapy, #brachy, #prostatecancer, and #pcsm.

CONCLUSIONS

The #ThisIsBrachytherapy inaugural campaign was successful and has continued to grow throughout the months after the initiation. By continuing to advocate for brachytherapy through the social media campaign #ThisIsBrachytherapy, we can empower radiation oncologists, especially trainees, and patients to address underutilization.

Geographical Variations in Prostate Cancer Outcomes: A Systematic Review of International Evidence

Background: Previous reviews of geographical disparities in the prostate cancer continuum from diagnosis to mortality have identified a consistent pattern of poorer outcomes with increasing residential disadvantage and for rural residents. However, there are no contemporary, systematic reviews summarizing the latest available evidence. Our objective was to systematically review the published international evidence for geographical variations in prostate cancer indicators by residential rurality and disadvantage.

Methods: Systematic searches of peer-reviewed articles in English published from 1/1/1998 to 30/06/2018 using PubMed, EMBASE, CINAHL, and Informit databases. Inclusion criteria were: population was adult prostate cancer patients; outcome measure was PSA testing, prostate cancer incidence, stage at diagnosis, access to and use of services, survival, and prostate cancer mortality with quantitative results by residential rurality and/or disadvantage. Studies were critically appraised using a modified Newcastle-Ottawa Scale.

Results: Overall 169 studies met the inclusion criteria. Around 50% were assessed as high quality and 50% moderate. Men from disadvantaged areas had consistently lower prostate-specific antigen (PSA) testing and prostate cancer incidence, poorer survival, more advanced disease and a trend toward higher mortality. Although less consistent, predominant patterns by rurality were lower PSA testing, prostate cancer incidence and survival, but higher stage disease and mortality among rural men. Both geographical measures were associated with variations in access and use of prostate cancer-related services for low to high risk disease.

Conclusions: This review found substantial evidence that prostate cancer indicators varied by residential location across diverse populations and geographies. While wide variations in study design limited comparisons across studies, our review indicated that internationally, men living in disadvantaged areas, and to a lesser extent more rural areas, face a greater prostate cancer burden. This review highlights the need for a better understanding of the complex social, environmental, and behavioral reasons for these variations, recognizing that, while important, geographical access is not the only issue. Implementing research strategies to help identify these processes and to better understand the central role of disadvantage to variations in health outcome are crucial to inform the development of evidence-based targeted interventions.

Implantable chemothermal brachytherapy seeds: A synergistic approach to brachytherapy using polymeric dual drug delivery and hyperthermia for malignant solid tumor ablation

Chemothermal brachytherapy seeds have been developed using a combination of polymeric dual drug chemotherapy and alternating magnetic field induced hyperthermia. The synergistic effect of chemotherapy and hyperthermia brachytherapy has been investigated in a way that has never been performed before, with an in-depth analysis of the cancer cell inhibition property of the new system. A comprehensive in vivo study on athymic mice model with SCC7 tumor has been conducted to determine optimal arrays and specifications of the chemothermal seeds. Dual drug chemotherapy has been achieved via surface deposition of polydopamine that carries bortezomib, and also via loading an acidic pH soluble hydrogel that contains 5-Fluorouracil inside the chemothermal seed; this increases the drug loading capacity of the chemothermal seed, and creates dual drug synergism. An external alternating magnetic field has been utilized to induce hyperthermia conditions, using the inherent ferromagnetic property of the nitinol alloy used as the seed casing. The materials used in this study were fully characterized using FESEM, H¹ NMR, FT-IR, and XPS to validate their properties. This new approach to experimental cancer treatment is a pilot study that exhibits the potential of thermal brachytherapy and chemotherapy as a combined treatment modality.

[Prostate brachytherapy: New techniques, new indications]

Prostate brachytherapy has been for a long time one of the standard treatments for low risk prostate cancer, with high rates of biochemical control and low levels of urinary and sexual late toxicity compared to other available techniques, namely external beam radiotherapy and radical prostatectomy. The aim of this article is to review the recent innovations of prostate brachytherapy, which suggest a bright future for the technique. We will discuss the extension of indications of permanent implant brachytherapy to favorable intermediate-risk patients, the use of novel isotopes such as Palladium 103 and Cesium 131, and the benefit of brachytherapy as a boost following external beam radiotherapy for intermediate and high-risk patients. We will also discuss the rise of high dose rate brachytherapy, as a boost or monotherapy, the increasing use of MRI for patient selection and treatment planning, as well as the development of brachytherapy as a means of focal therapy.

Prostate cancer high dose-rate brachytherapy: review of evidence and current perspectives

INTRODUCTION

Patients with intermediate to high risk disease (prostate specific antigen (PSA) ≥ 10, Gleason score ≥ 7, or clinical stage ≥ T2b) suffer from poorer long-term biochemical control (freedom from an increasing prostate specific antigen level) when treated with external beam radiation (EBRT) alone. In order to improve biochemical control while limiting long-term complications, brachytherapy has been incorporated into radiotherapy treatment, either alone or in combination with EBRT.

AREAS COVERED

Current literature regarding the use of high dose-rate (HDR) brachytherapy for localized prostate cancer, including as a boost and monotherapy. The efficacy and toxicities of various approaches are evaluated including comparisons to low dose-rate (LDR) brachytherapy.

EXPERT COMMENTARY

Prostate HDR brachytherapy has higher conformality than EBRT, potentially improving the therapeutic ratio by allowing higher doses per fraction to tumor cells. The improved biochemical control shown in trials have resulted in EBRT plus brachytherapy to be included as a standard treatment option supported by the NCCN and ASCO guidance documents for intermediate to high risk prostate cancer.

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.