Is prostate brachytherapy a dying art? Trends and variation in the definitive management of prostate cancer in Ontario, Canada

Review of brachytherapy clinical trials: a cross-sectional analysis of ClinicalTrials.gov

INTRODUCTION

Characterizing the landscape of clinical trials including brachytherapy can provide an overview of the current status and research trends which may guide further areas of investigation.

METHOD

We queried 449,849 clinical trials from the ClinicalTrials.gov registry using brachytherapy-related keywords from 1980 to 2023, yielding 245 multi-arm and 201 single-arm, brachytherapy trials. Multi-arm and single-arm brachytherapy trials were compared using 12 trial protocol elements.

RESULTS

The number of trials including brachytherapy has increased over time, with over 60% of trials registered in 2010 onwards. The majority of clinical trials were Phase 2 or 3, evaluated both safety and efficacy, and were funded by academic sponsors. The most common tumor sites evaluated in brachytherapy clinical trials include prostate, cervix, liver, endometrium, and breast.

CONCLUSION

There remains continued interest in clinical trials including brachytherapy focused on evaluation of novel delivery systems, treatment planning, and new indications. More brachytherapy clinical trials are needed to define the optimal clinical utilization and advance prospective research in this field.

Challenges in the Sustainability of Brachytherapy Service in Contemporary Radiotherapy

Brachytherapy has a long history of delivering a highly conformal radiation dose to the target volume with sparing of adjacent normal tissue and has an irreplaceable role in certain cancers, such as cervical and prostate cancers. There have been futile attempts to replace brachytherapy with other radiation techniques. Despite that there are multifaceted challenges in preserving this dying art, from establishment, to a trained workforce, to maintenance of the equipment and source replacement costs. Here we focus on the challenges to access brachytherapy, the availability and distribution of care across the globe and appropriate training leading to proper implementation of the procedure. Brachytherapy holds a significant place in the treatment armamentarium of most common cancers, such as cervical, prostate, head and neck and skin cancers. However, there is an uneven distribution of brachytherapy facilities, not only across the globe, but also at a national level, with a larger proportion of facilities concentrated in certain regions, more so in low and low-middle income countries. The regions with the highest incidence of cervical cancer have the least access to brachytherapy facilities. Attempts to bridge the gap are essential and should be focused on uniform distribution and access to care, improving training of the workforce through specialised training programmes, reducing the cost of care, planning to reduce the recurring cost, generating evidence and research guidelines, renewing interest in brachytherapy through rebranding, use of social media and building an attainable long-term roadmap.

Brachytherapy boost improves survival and decreases risk of developing distant metastases compared to external beam radiotherapy alone in intermediate and high risk group prostate cancer patients

BACKGROUND AND PURPOSE

Despite several prospective trials showing a clinical benefit of combining external beam radiotherapy (EBRT) with brachytherapy boost (BTB) for the treatment of intermediate- and high-risk prostate cancer (PCa) patients, none of these trials were designed to test for a survival difference. In this study, we aimed to collect a large multi-institutional database to determine whether BT boost was associated with a statistically significant improvement in survival and a reduction of distant metastases based on real-world data.

MATERIAL AND METHODS

We collected the data of patients treated for intermediate- or high-risk PCa with definitive EBRT or BTB, with or without androgen deprivation therapy (ADT), between January 2003 and December 2014 at two tertiary institutions. The statistical endpoints included overall survival (OS), freedom from distant metastases (FFDM), and metastases-free survival (MFS). The impact of treatment modality was assessed using Cox regression models and log-rank testing after one-to-one propensity score matching.

RESULTS

A total of 1641 patients treated with EBRT (n=1148) or high-dose-rate BTB (n=493) were analyzed. The median survival and clinical follow-up were 117.8 (IQR 78-143.3) and 60.7 months, respectively. The radiotherapy modality (BTB) remained an independent prognostic factor for OS (HR 0.75; 95% CI 0.63-0.88; p<0.001), FFDM (HR 0.54; 95% CI 0.4-0.73; p<0.001), and MFS (HR 0.72; 95% CI 0.61-0.85; p<0.001). After propensity score matching, the remaining 986 patients were well-balanced in terms of age, maximum PSA, ISUP grade group, and TNM T stage. OS (p=0.001), FFDM (p<0.001) and MFS (p<0.001) were significantly higher in the BTB group.

CONCLUSIONS

There is a strong positive association between BTB and OS, FFDM, and MFS in PCa patients treated with definitive RT for intermediate- or high-risk PCa.

Real-world utilisation of brachytherapy boost and patient-reported functional outcomes in men who had external beam radiation therapy for prostate cancer in Australia

Background and purpose

We aimed to evaluate utilisation of brachytherapy (BT) boost in men who had external beam radiation therapy (EBRT) for prostate cancer, and to compare patient-reported functional outcomes (PRO) following each approach in a population-based setting in Australia.

Materials and methods

This is a population-based cohort of men with localised prostate cancer enrolled in the Victorian Prostate Cancer Outcomes Registry, who had EBRT between 2015 and 2020. Primary outcomes were proportion who had BT-boost, and PRO (assessed using the EPIC-26 questionnaires) 12 months post-treatment. Multivariable logistic regressions were used to evaluate factors associated with BT-boost, and linear regressions were used to estimate differences in EPIC-26 domain scores between EBRT alone and EBRT + BT.

Results

Of the 1,626 men in the study, 88 (5.4 %) had BT-boost. Factors independently associated with BT-boost were younger age, higher socioeconomic status, and treatment in public institutions. 1,555 men completed EPIC-26 questionnaires. No statistically or clinically significant differences in EPIC-26 urinary, sexual and bowel functional domain scores were observed between men who had EBRT + BT vs EBRT alone, with adjusted mean differences in urinary incontinence, urinary irritative/ obstruction, sexual, and bowel domain of 1.28 (95 %CI = -3.23 to 5.79), -2.87 (95 %CI = -6.46 to 0.73), 0.49 (95 %CI = -4.78 to 5.76), and 2.89 (95 %CI = -0.83 to 6.61) respectively.

Conclusion

1-in-20 men who had EBRT for prostate cancer had BT-boost. This is the first time that PRO following EBRT+/-BT is reported at a population-based level in Australia, with no evidence to suggest worse PRO with addition of BT-boost 12 months post-treatment.

A Prospective Study of MR-Guided Focal Salvage High Dose-Rate Brachytherapy for Radiorecurrent Prostate Cancer: Updated Results of 30 Patients

PURPOSE

Limited prospective data on focal salvage high dose-rate (HDR) prostate brachytherapy are available. We sought to explore the toxicities, health related quality of life (HRQOL) and efficacy of focal salvage HDR brachytherapy in a prospective clinical trial. This report represents updated results of previously published data.

MATERIALS AND METHODS

Patients with locally recurrent prostate cancer after previous external beam radiotherapy and/or brachytherapy were enrolled. Patients received MRI-guided, ultrasound-based focal HDR brachytherapy delivered over two fractions of 13.5 Gy delivered 1-2 weeks apart. Androgen deprivation therapy (ADT) was not used.

RESULTS

Thirty patients were treated between 2012-2019. At a median follow-up of 39 months, the three-year biochemical failure-free rate was 61.8% (95% CI 44.0-86.6%), and three-year ADT/salvage therapy-free rate was 86.0% (95% CI 74.1-99.8%). Seventeen patients experienced subsequent biochemical failure, 9 have received ADT and/or further local salvage, and no patients have died from prostate cancer. Of the 28 patients who had a post-treatment MRI, 26 had a local treatment response. No acute grade ≥ 3 GU/GI toxicity was observed. One temporary late grade 3 GU toxicity event occurred, and no late grade ≥ 3 GI toxicity was seen. No significant decline in urinary or bowel HRQOL was observed.

CONCLUSIONS

Focal salvage HDR brachytherapy has a favourable side effect profile, no significant decline in HRQOL and 3-year biochemical control rates in line with other salvage options. While early MRI response at the treated site is common, this does not preclude subsequent biochemical failure.

Ultrahypofractionated Radiotherapy for Localised Prostate Cancer: How Far Can We Go?

Following adoption of moderately hypofractionated radiotherapy as a standard for localised prostate cancer, ultrahypofractioned radiotherapy delivered in five to seven fractions is rapidly being embraced by clinical practice and international guidelines. However, the question remains: how low can we go? Can radiotherapy for prostate cancer be delivered in fewer than five fractions? The current review summarises the evidence that radiotherapy for localised prostate cancer can be safely and effectively delivered in fewer than five fractions using high dose rate brachytherapy or stereotactic body radiotherapy. We also discuss important lessons learned from the single-fraction high dose rate brachytherapy experience.

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.

Characterizing Surgical and Radiotherapy Outcomes in Non-metastatic High-Risk Prostate Cancer: A Systematic Review and Meta-Analysis

Background Identifying the optimal management of high-risk non-metastatic prostate cancer (PCa) is an important public health concern, given the large burden of this disease. We performed a meta-analysis of studies comparing PCa-specific mortality (CSM) among men diagnosed with high-risk non-metastatic PCa who were treated with primary radiotherapy (RT) and radical prostatectomy (RP). Methods Medline and Embase were searched for articles between January 1, 2005, and February 11, 2020. After title and abstract screening, two authors independently reviewed full-text articles for inclusion. Data were abstracted, and a modified version of the Newcastle-Ottawa Scale, involving a comprehensive list of confounding variables, was used to assess the risk of bias. Results Fifteen studies involving 131,392 patients were included. No difference in adjusted CSM in RT relative to RP was shown (hazard ratio, 1.02 [95% confidence interval: 0.84, 1.25]). Increased CSM was found in a subgroup analysis comparing external beam radiation therapy (EBRT) with RP (1.35 [1.10, 1.68]), whereas EBRT combined with brachytherapy (BT) versus RP showed lower CSM (0.68 [0.48, 0.95]). All studies demonstrated a high risk of bias as none fully adjusted for all confounding variables. Conclusion We found no difference in CSM between men diagnosed with non-metastatic high-risk PCa and treated with RP or RT; however, this is likely explained by increased CSM in men treated with EBRT and decreased CSM in men treated with EBRT + BT studies relative to RP. High risk of bias in all studies identifies the need for better data collection and confounding control in the PCa research.

The Case for Brachytherapy: Why It Deserves a Renaissance

The recent global events related to the coronavirus disease of 2019 pandemic have significantly changed the medical landscape and led to a shift in oncologic treatment perspectives. There is a renewed focus on preserving treatment outcomes while maintaining medical accessibility and decreasing medical resource utilization. Brachytherapy, which is a vital part of the treatment course of many cancers (particularly prostate and gynecologic cancers), has the ability to deliver hypofractionated radiation and thus shorten treatment time. Studies in the early 2000s demonstrated a decline in brachytherapy usage despite data showing equivalent or even superior treatment outcomes for brachytherapy in disease sites, such as the prostate and cervix. However, newer data suggest that this trend may be reversing. The renewed call for shorter radiation courses based on data showing equivalent outcomes will likely establish hypofractionated radiation as the standard of care across multiple disease sites. With shifting reimbursement, brachytherapy represents the pinnacle in hypofractionated, conformal radiation therapy, and with extensive long-term data in support of the treatment modality brachytherapy is primed for a renaissance.

Ultra-hypofractionated radiotherapy for low- and intermediate risk prostate cancer: High-dose-rate brachytherapy vs stereotactic ablative radiotherapy

PURPOSE

To compare the biochemical control rates (BCRs), late gastrointestinal (GI) and genitourinary (GU) toxicities in patients with low- and intermediate risk prostate cancer (PCa) treated with high-dose-rate brachytherapy (HDR BT) of 19 Gy/1 fraction, 26 Gy/2 fractions, or stereotactic ablative radiotherapy (SABR) of 36.25 Gy/5 fractions.

METHODS AND MATERIALS

Between August 2008 and December 2017, patients with low- and intermediate risk PCa who received single dose or 2-fraction HDR BT, or 5-fraction SABR at a single institution were included. BCR for the whole population and the individual treatment groups were calculated using the Phoenix definition. Post treatment GI and GU toxicities were evaluated according to the CTCAE v4.0 guidelines.

RESULTS

185 patients with low- and intermediate risk PCa were included in this study with a median follow up of 60.5 months. BCRs at 3 and 5 years were 95% and 85% for all patients. The 5-year BCRs were 69%, 95% and 92% for the 19 Gy/1 fraction, 26 Gy/2 fractions and 36.25 Gy/5 fractions groups respectively. The cumulative 5-year incidence rates of ≥grade 2 GI events in the 19 Gy/1fr, 26 Gy/2fr and 36.25 Gy/5fr groups were 0%, 2% and 4%, respectively. Incidence rates in those treated in the 5-fraction SABR arm were significantly higher (p < 0.05) than those treated in both HDR BT arms where no statistically significant difference between the two HDR BT groups was seen (p = 0.15). The cumulative 5-year incidence rates of ≥grade 2 GU events in the 19 Gy/1fr, 26 Gy/2fr and 36.25 Gy/5fr groups were 30%, 5% and 6%, respectively. No statistically significant difference was found between the 26 Gy/2fr and 36.25 Gy/5fr (p = 0.37) treatment arms but the incidence rate in the 26 Gy/2fr were significantly lower than those seen after 19 Gy/1fr (p < 0.05).

CONCLUSIONS

26 Gy/2 fractions HDR BT provided equivalent BCR with lower toxicity compared to 36.25 Gy/5 fractions SABR. Both 2-fraction HBR BT and 5-fraction SABR achieved better BCRs than single dose 19 Gy HDR BT. The two-fraction HDR BT schedule should be considered as an important comparator in future clinical trials.

Prostate high dose-rate brachytherapy as monotherapy for prostate cancer: Late toxicity and patient reported outcomes from a randomized phase II clinical trial

BACKGROUND AND PURPOSE

Long-term toxicity of high dose-rate brachytherapy as monotherapy for prostate cancer is not well defined. We report late toxicity and health related quality of life (HRQOL) changes from a randomized phase II clinical trial of two different fractionation schemes.

MATERIALS AND METHODS

Eligible patients had NCCN low or intermediate risk prostate cancer. 170 patients were randomized to receive either a single 19 Gy or two-fractions of 13.5 Gy one week apart. Toxicity was measured using Common Terminology for Adverse Events (CTCAE) v4.0, and HRQOL was measured using the Expanded Prostate Index Composite (EPIC).

RESULTS

Median follow-up was 63 months. The 5-year cumulative incidence of Grade 2 or higher genitourinary (GU) and gastrointestinal (GI) toxicity was 62% and 12% in the single-fraction arm, and 47% and 9% in the two-fraction arm, respectively. Grade 3 GU toxicity was only seen in the single fraction arm with a cumulative incidence of 2%. The 5-year prevalence of Grade 2 GU toxicity was 29% and 21%, in the single- and two-fraction arms, respectively, with Grade 2 GI toxicity of 1% and 2%. Beyond the first year, no significant differences in mean urinary HRQOL were seen compared to baseline in the two-fraction arm, in contrast to the single-fraction arm where a decline in urinary HRQOL was seen at 4 and 5 years. Sexual HRQOL was significantly reduced in both treatment arms at all timepoints, with no changes in the bowel domain.

CONCLUSIONS

HDR monotherapy is well tolerated with minimal impact on HRQOL.