Addition of Androgen-Deprivation Therapy or Brachytherapy Boost to External Beam Radiotherapy for Localized Prostate Cancer: A Network Meta-Analysis of Randomized Trials

Biochemical control in intermediate- and high-risk prostate cancer after EBRT with and without brachytherapy boost

PURPOSE

External beam radiotherapy (EBRT) with or without brachytherapy boost (BTB) has not been compared in prospective studies using guideline-recommended radiation dose and recommended androgen-deprivation therapy (ADT). In this multicenter retrospective analysis, we compared modern-day EBRT with BTB in terms of biochemical control (BC) for intermediate-risk (IR) and high-risk (HR) prostate cancer.

METHODS

Patients were treated for primary IR or HR prostate cancer during 1999-2019 at three high-volume centers. Inclusion criteria were prescribed ≥ 76 Gy EQD2 (α/β = 1.5 Gy) for IR and ≥ 78 Gy EQD2 (α/β = 1.5 Gy) for HR as EBRT alone or with BTB. All HR patients received ADT and pelvic irradiation, which were optional in IR cases. BC between therapies was compared in survival analyses.

RESULTS

Of 2769 initial patients, 1176 met inclusion criteria: 468 HR (260 EBRT, 208 BTB) and 708 IR (539 EBRT, 169 BTB). Median follow-up was 49 and 51 months for HR and IR, respectively. BTB patients with ≥ 113 Gy EQD2Gy experienced a stable, good BC outcome compared with BTB at lower doses. Patients treated with ≥ 113 Gy EQD2Gy also experienced significantly improved BC compared with EBRT (10-year BC failure rates after ≥ 113 Gy BTB and EBRT: respectively 20.4 and 41.8% for HR and 7.5 and 20.8% for IR).

CONCLUSIONS

In patients with IR and HR prostate cancer, BTB with ≥ 113 Gy EQD2Gy offered a BC advantage compared with dose-escalated EBRT and lower BTB doses.

Assessing the toxicity after moderately hypofractionated prostate and whole pelvis radiotherapy compared to conventional fractionation

OBJECTIVE

To evaluate acute and late gastrointestinal (GI) and genitourinary (GU) toxicities after moderately hypofractionated (HF) or conventionally fractionated (CF) primary whole-pelvis radiotherapy (WPRT).

METHODS

Primary prostate-cancer patients treated between 2009 and 2021 with either 60 Gy at 3 Gy/fraction to the prostate and 46 Gy at 2.3 Gy/fraction to the whole pelvis (HF), or 78 Gy at 2 Gy/fraction to the prostate and 50/50.4 Gy at 1.8-2 Gy/fraction to the whole pelvis (CF). Acute and late GI and GU toxicities were retrospectively assessed.

RESULTS

106 patients received HF and 157 received CF, with a median follow-up of 12 and 57 months. Acute GI toxicity rates in the HF and CF groups were, respectively, grade 2: 46.7% vs. 37.6%, and grade 3: 0% vs. 1.3%, with no significant difference (p = 0.71). Acute GU toxicity rates were, respectively, grade 2: 20.0% vs. 31.8%, and grade 3: 2.9% vs. 0%, (p = 0.04). We compared prevalence of late GI and GU toxicities between groups after 3, 12, and 24 months and did not find any significant differences (respectively, p = 0.59, 0.22, and 0.71 for GI toxicity; p = 0.39, 0.58, and 0.90 for GU toxicity).

CONCLUSION

Moderate HF WPRT was well tolerated during the first 2 years. Randomized trials are needed to confirm these findings.

The Current Trend of Radiation Therapy for Patients with Localized Prostate Cancer

A recent approach to radiotherapy for prostate cancer is the administration of high doses of radiation to the prostate while minimizing the risk of side effects. Thus, image-guided radiotherapy utilizes advanced imaging techniques and is a feasible strategy for increasing the radiation dose. New radioactive particles are another approach to achieving high doses and safe procedures. Prostate brachytherapy is currently considered as a combination therapy. Spacers are useful to protect adjacent organs, specifically the rectum, from excessive radiation exposure.

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.

Outcomes following brachytherapy boost for intermediate- and high-risk prostate cancer: A retrospective bicenter study by the SFRO brachytherapy group

INTRODUCTION

Radiotherapy dose escalation improves biochemical control in intermediate- or high-risk prostate cancer. Brachytherapy boost was shown to further improve biochemical control compared to radiotherapy alone in three randomized trials. The SFRO brachytherapy group sought to evaluate the efficacy and toxicity of BT-boost for intermediate and high-risk prostate cancer in real life, and to determine prognostic factors for efficacy and toxicity.

MATERIAL AND METHOD

A retrospective study was conducted, including all patients with intermediate- or high-risk prostate cancer treated with a combination of external beam radiotherapy (EBRT) and high dose-rate brachytherapy boost (HDR-BB), from 2006 until December 2019 at two centers. Patient characteristics, initial disease, treatment and follow-up were collected.

RESULTS

709 patients from two centers were analyzed given a short follow-up in the other centers. Out of those, 277 were intermediate risk (170 favorable and 107 unfavorable) and 432 were high risk. The median EBRT and HDR-BB doses were 46 Gy (35-50) and 14 Gy (10-20). After a median follow-up of 62 months, biochemical control at 5 years was 87.5 % for the overall population, 91 % and 85 % for intermediate- and high-risk cancers, respectively. At 5 years, biochemical and clinical relapse-free survival, metastasis-free survival and local control rates were 83 %, 90 % and 97 % respectively. 5-years overall survival was 94 %. Late grade 2 or higher GU or GI toxicity was found in 36 patients (5 %) and 9 patients (1.3 %).

CONCLUSION

This bicenter analysis shows the efficacy and tolerability of HDR-BB as a complement to external radiotherapy. Further improvements such as combination with new hormonal agents or new brachytherapy-radiotherapy fractionation regimens are warranted to improve further the outcomes and therapeutic ratio.

ESTRO-ACROP recommendations for evidence-based use of androgen deprivation therapy in combination with external-beam radiotherapy in prostate cancer

BACKGROUND AND PURPOSE

There is no consensus concerning the appropriate use of androgen deprivation therapy (ADT) during primary and postoperative external-beam radiotherapy (EBRT) in the management of prostate cancer (PCa). Thus, the European Society for Radiotherapy and Oncology (ESTRO) Advisory Committee for Radiation Oncology Practice (ACROP) guidelines seeks to present current recommendations for the clinical use of ADT in the various indications of EBRT.

MATERIAL AND METHODS

A literature search was conducted in MEDLINE PubMed that evaluated EBRT and ADT in prostate cancer. The search focused on randomized, Phase II and III trials published in English from January 2000 to May 2022. In case topics were addressed in the absence of Phase II or III trials, recommendations were labelled accordingly based on the limited body of evidence. Localized PCa was classified according to D'Amico et al. classification in low-, intermediate and high risk PCa. The ACROP clinical committee identified 13 European experts who discussed and analyzed the body of evidence concerning the use of ADT with EBRT for prostate cancer.

RESULTS

Key issues were identified and are discussed: It was concluded that no additional ADT is recommended for low-risk prostate cancer patients, whereas for intermediate- and high-risk patients four to six months and two to three years of ADT are recommended. Likewise, patients with locally advanced prostate cancer are recommended to receive ADT for two to three years and when ≥ 2 high-risk factors (cT3-4, ISUP grade ≥ 4 or PSA ≥ 40 ng/ml) or cN1 is present ADT for three years plus additional Abiraterone for two years is recommended. For postoperative patients no ADT is recommended for adjuvant EBRT in pN0 patients whereas for pN1 patients adjuvant EBRT with long-term ADT is performed for at least 24 to 36 months. In the setting of salvage EBRT ADT is performed in biochemically persistent PCa patients with no evidence of metastatic disease. Long-term ADT (24 months) is recommended in pN0 patients with high risk of further progression (PSA ≥ 0.7 ng/ml and ISUP grade group ≥ 4) and a life expectancy of over ten years, whereas short-term ADT (6 months) is recommended in pN0 patients with lower risk profile (PSA < 0.7 ng/ml and ISUP grade group 4). Patients considered for ultra-hypofractionated EBRT as well as patients with image based local recurrence within the prostatic fossa or lymph node recurrence should participate in appropriate clinical trials evaluating the role of additional ADT.

CONCLUSION

These ESTRO-ACROP recommendations are evidence-based and relevant to the use of ADT in combination with EBRT in PCa for the most common clinical settings.

Molecular Mechanisms of Noncoding RNA in the Occurrence of Castration-Resistant Prostate Cancer

Although several therapeutic options have been shown to improve survival of most patients with prostate cancer, progression to castration-refractory state continues to present challenges in clinics and scientific research. As a highly heterogeneous disease entity, the mechanisms of castration-resistant prostate cancer (CRPC) are complicated and arise from multiple factors. Among them, noncoding RNAs (ncRNAs), the untranslated part of the human transcriptome, are closely related to almost all biological regulation, including tumor metabolisms, epigenetic modifications and immune escape, which has encouraged scientists to investigate their role in CRPC. In clinical practice, ncRNAs, especially miRNAs and lncRNAs, may function as potential biomarkers for diagnosis and prognosis of CRPC. Therefore, understanding the molecular biology of CRPC will help boost a shift in the treatment of CRPC patients. In this review, we summarize the recent findings of miRNAs and lncRNAs, discuss their potential functional mechanisms and highlight their clinical application prospects in CRPC.

Prostate cancer in transgender women: considerations for screening, diagnosis and management

Transgender individuals represent 0.55% of the US population, equivalent to 1.4 million transgender adults. In transgender women, feminisation can include a number of medical and surgical interventions. The main goal is to deprive the phenotypically masculine body of androgens and simultaneously provide oestrogen therapy for feminisation. In gender-confirming surgery (GCS) for transgender females, the prostate is usually not removed. Due to limitations of existing cohort studies, the true incidence of prostate cancer in transgender females is unknown but is thought to be less than the incidence among cis-gender males. It is unclear how prostate cancer develops in androgen-deprived conditions in these patients. Six out of eleven case reports in the literature presented with metastatic disease. It is thought that androgen receptor-mediated mechanisms or tumour-promoting effects of oestrogen may be responsible. Due to the low incidence of prostate cancer identified in transgender women, there is little evidence to drive specific screening recommendations in this patient subpopulation. The treatment of early and locally advanced prostate cancer in these patients warrants an individualised thoughtful approach with input from patients' reconstructive surgeons. Both surgical and radiation treatment for prostate cancer in these patients can profoundly impact the patient's quality of life. In this review, we discuss the evidence surrounding screening and treatment of prostate cancer in transgender women and consider the current gaps in our knowledge in providing evidence-based guidance at the molecular, genomic and epidemiological level, for clinical decision-making in the management of these patients.

Cardiovascular toxicities of androgen deprivation therapy in Asian men with localized prostate cancer after curative radiotherapy: a registry-based observational study

Background

Androgen deprivation therapy (ADT) and radiotherapy (RT) are the mainstay treatment for localized prostate cancer and recurrence after surgery. Cardiovascular (CV) toxicity of ADT is increasingly recognized, and the risk relates to pre-existing risk factors and ADT modalities. Despite ethnic differences in the prevalence of CV risk factors and variations of CV mortality, data on ADT-related cardiotoxicities in the Asian population remain inconclusive. Our registry-based study investigated ADT-related major adverse cardiovascular events (MACE) after primary or salvage RT.

Methods

Our study combined two prospectively established registry databases from National Cancer Center Singapore and National Heart Center Singapore. The primary endpoint is time to first MACE after treatment. MACE is defined as myocardial infarction, stroke, unstable angina, or cardiovascular death. Two types of propensity score adjustments, including ADT propensity score as a covariate in the multivariable regression model and propensity score weighting, were applied to balance baseline features and CV risk factors between RT alone and RT + ADT groups.

Results

From 2000 to 2019, 1940 patients received either RT alone (n = 494) or RT + ADT (n = 1446) were included. After a median follow-up of 10 years (RT) and 7.2 years (RT+ ADT), the cumulative incidence of MACE at 1, 3 and 9 years was 1.2, 5 and 16.2% in RT group, and 1.1, 5.2 and 17.6% in RT + ADT group, respectively. There were no differences in the incidence of MACE between 2 groups (HR 1.01, 95% CI 0.78–1.30, p = 0.969). Pre-treatment CV risk factors were common (80%), and CV disease (15.9%) was the second leading cause of death after prostate cancer (21.1%). On univariate analysis, older age, Indians and Malays, pre-existing CV risk factors, and history of MACE were associated with higher MACE risk. After propensity score adjustments, there remained no significant differences in MACE risk between RT + ADT and RT group on multivariable analysis.

Conclusions

In our registry-based study, ADT is not associated with increased risk of major cardiovascular events among Southeast Asian men with prostate cancer after curative radiotherapy.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40959-022-00131-4.

Phase II Study of ENZAlutamide Combined With Hypofractionated Radiation Therapy (ENZART) for Localized Intermediate Risk Prostate Cancer

Background

Intermediate-risk prostate cancer (PCa) is usually treated by a combination of external beam radiation therapy (EBRT) and a short course of androgen deprivation therapy (ADT). ADT is associated with multiple side effects, including weight gain, loss of libido, and hot flashes. In contrast, anti-androgen monotherapy is generally better tolerated in spite of higher rates of gynecomastia.

Objective

This study assessed the effectiveness of enzalutamide monotherapy combined with hypofractionated EBRT (Hypo-EBRT) for treating intermediate risk prostate cancer.

Method

This trial was a multicenter, open-label phase II study of 6 months of enzalutamide monotherapy combined with Hypo-EBRT for intermediate-risk prostate cancer. Hypo-EBRT was initiated 8–12 weeks after initiating enzalutamide. The primary endpoint was PSA decline &gt;80% measured at the 25th week of enzalutamide administration. Secondary end-points included assessment of toxicity, changes in anthropomorphic body measurements, sexual hormones, and metabolic changes.

Results

Sixty-two patients were included in the study from January 2018 to February 2020. A PSA decline of &gt;80% was observed in all evaluable patients at the end of enzalutamide treatment and 92% achieved PSA values under 0.1 ngr/ml. All patients remain in PSA response (&lt;80% reduction of the initial values) 6 months after the end of enzalutamide treatment. The most frequent adverse events were hypertension, asthenia, and gynecomastia. There were no significant changes in bone density, body mass index (BMI), or patient-reported outcomes (PROs).

Conclusion

Enzalutamide monotherapy is very effective along with hEBRT in reducing PSA levels for patients with intermediate-risk prostate cancer. Longer follow-up is needed to confirm the potential use of this combination in future randomized trials.

Co-Inhibition of Androgen Receptor and PARP as a Novel Treatment Paradigm in Prostate Cancer-Where Are We Now?

Metastatic prostate cancer remains lethal with a 5-year survival rate of about 30%, indicating the need for better treatment options. Novel antiandrogens (NAA)-enzalutamide and abiraterone-have been the mainstay of treatment for advanced disease since 2011. In patients who progress on the first NAA, responses to the second NAA are infrequent (25-30%) and short-lasting (median PFS ~3 months). With the growing adoption of NAA therapy in pre-metastatic castration-resistant settings, finding better treatment options for first-line mCRPC has become an urgent clinical need. The regulatory approval of two PARP inhibitors in 2020-rucaparib and olaparib-has provided the first targeted therapy option for patients harboring defects in selected DNA damage response and repair (DDR) pathway genes. However, a growing body of preclinical and clinical data shows that co-inhibition of AR and PARP induces synthetic lethality and could be a promising therapy for patients without any DDR alterations. In this review article, we will investigate the limitations of NAA monotherapy, the mechanistic rationale for synthetic lethality induced by co-inhibition of AR and PARP, the clinical data that have led to the global development of a number of these AR and PARP combination therapies, and how this may impact patient care in the next 2-10 years.

Trends in Androgen Deprivation Use in Men with Intermediate Risk Prostate Cancer Who Underwent Radiotherapy

Purpose

Until 2018, National Cancer Comprehensive Network guidelines recommended androgen deprivation therapy (ADT) for all men with intermediate-risk prostate cancer who had undergone radiation therapy. Intermediate risk was stratified as favorable and unfavorable in 2018, and ADT recommendation was limited to men with unfavorable intermediate-risk prostate cancer. Data suggesting this stratification and treatment deintensification were first published in December 2013. This study characterizes US national trends for demographic, clinical, and socioeconomic factors associated with ADT use in men with intermediate-risk prostate cancer who have undergone definitive radiation therapy.

Methods and Materials

This retrospective cohort study examined 108,185 men in the National Cancer Database who were diagnosed with intermediate-risk prostate cancer from 2004 to 2016. Temporal trends in demographic, clinical, and socioeconomic factors among men with intermediate-risk prostate cancer and associations with the use of ADT were characterized.

Results

In total, 108,185 men diagnosed with intermediate-risk prostate cancer underwent radiation therapy from 2004 to 2016. Of these men, 41.09% received ADT. Among the 60,705 men with favorable intermediate-risk prostate cancer, 32.06% received ADT. Among the 47,480 men with unfavorable intermediate-risk prostate cancer, 52.64% received ADT. On multivariate analysis, use of ADT was associated with age and year of diagnosis; being a race other than White; having government-based insurance; having a higher prostate-specific antigen level, tumor stage, and Gleason score; receiving treatment at a nonacademic center; and receiving external beam radiation therapy alone.

Conclusions

The findings highlight that ADT use is variable in men undergoing definitive radiation therapy for intermediate-risk prostate cancer, with the data suggesting that several clinical and socioeconomic disparities influence its use. The findings suggest that a significant proportion of men with favorable intermediate-risk prostate cancer receive ADT and remain candidates for treatment de-escalation, whereas a significant proportion of men with unfavorable intermediate-risk prostate cancer may be undertreated when ADT is omitted.

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.

An Expert Review on the Combination of Relugolix with Definitive Radiation Therapy for Prostate Cancer

Androgen deprivation therapy (ADT) is an integral component in the management of prostate cancer across multiple disease states. Traditionally, luteinizing hormone-releasing hormone (LHRH) agonists constituted the backbone of ADT. However, gonadotropin-releasing hormone receptor hormone (GnRH) antagonists are also available, which offer faster testosterone suppression and reduced likelihood of ADT-related adverse effects compared to LHRH agonists, including the potential for fewer ADT-associated major cardiac events. Until recently, all forms of LHRH agonists and GnRH antagonist formulations are of parenteral administration. However, recently relugolix gained FDA approval as the first oral GnRH antagonist. Relugolix achieves faster and more complete testosterone suppression compared to an LHRH agonist. This translates to more rapid prostate-specific antigen response compared to LHRH agonists. After discontinuation of relugolix, testosterone recovers faster than after GnRH agonists or injectable GnRH antagonist therapy. Overall, these factors provide opportunities for more precisely defined ADT duration when combined with radiation therapy. The rapid onset and offset testosterone suppression with relugolix, however, may require physicians to rethink the mechanism and goals of ADT when prescribing. As an oral formulation, relugolix enables patients to avoid pain and injection site reactions, limit extra office visits for injections, and achieve a shorter duration of experiencing the side effects of castrate testosterone levels. This convenience and tolerability may enhance physicians' willingness to prescribe ADT and patients' feeling of control over their ADT course, but the potential advantages are accompanied by the risks of patients choosing to discontinue therapy to escape side effects of ADT. This article focuses on different aspects of what is known and unknown regarding the optimal use of ADT and radiation therapy, and how relugolix, due to its properties, fit into our current treatment paradigms for localized prostate cancer.

Two-Weekly High-Dose-Rate Brachytherapy Boost After External Beam Radiotherapy for Localized Prostate Cancer: Long-Term Outcome and Toxicity Analysis

Purpose

Evaluation of clinical outcome of two-weekly high-dose-rate brachytherapy boost after external beam radiotherapy (EBRT) for localized prostate cancer.

Methods

338 patients with localized prostate cancer receiving definitive EBRT followed by a two-weekly high-dose-rate brachytherapy boost (HDR-BT boost) in the period of 2002 to 2019 were analyzed. EBRT, delivered in 46 Gy (D_Mean) in conventional fractionation, was followed by two fractions HDR-BT boost with 9 Gy (D_90%) two and four weeks after EBRT. Androgen deprivation therapy (ADT) was added in 176 (52.1%) patients. Genitourinary (GU)/gastrointestinal (GI) toxicity was evaluated utilizing the Common Toxicity Criteria for Adverse Events (version 5.0) and biochemical failure was defined according to the Phoenix definition.

Results

Median follow-up was 101.8 months. 15 (4.4%)/115 (34.0%)/208 (61.5%) patients had low-/intermediate-/high-risk cancer according to the D`Amico risk classification. Estimated 5-year and 10-year biochemical relapse-free survival (bRFS) was 84.7% and 75.9% for all patients. The estimated 5-year bRFS was 93.3%, 93.4% and 79.5% for low-, intermediate- and high-risk disease, respectively. The estimated 10-year freedom from distant metastasis (FFM) and overall survival (OS) rates were 86.5% and 70.0%. Cumulative 5-year late GU toxicity and late GI toxicity grade ≥ 2 was observed in 19.3% and 5.0% of the patients, respectively. Cumulative 5-year late grade 3 GU/GI toxicity occurred in 3.6%/0.3%.

Conclusions

Two-weekly HDR-BT boost after EBRT for localized prostate cancer showed an excellent toxicity profile with low GU/GI toxicity rates and effective long-term biochemical control.

Treatment of intermediate-risk prostate cancer with Cs-131: Long-term results from a single institution

PURPOSE

To evaluate our institutional outcomes utilizing Cs-131 prostate brachytherapy (PB) for the intermediate-risk (IR) group of prostate cancer patients.

METHODS AND MATERIALS

We reviewed a prospectively collected database of men treated with Cs-131 PB between 2006 and 2019. Patients with less than 24-months follow-up were excluded. Patients were classified as IR if they had one of the following factors: Gleason Score 7, prostate specific antigen >10 but <20 ng/mL, or T2b-c on clinical exam. We defined unfavorable-IR (UIR) as having either Grade Group 3, >1 IR factors, or ≥50% positive core biopsies. The Kaplan-Meier method was used to estimate actuarial event-time probabilities for biochemical freedom from disease (BFD).

RESULTS

A total of 335 patients with a median follow-up of 70.1 months (IQR 48.3-106.3 months) were identified. Androgen deprivation therapy (ADT) was used in 7.2% of patients. Favorable-IR (FIR) patients were commonly treated with PB alone (91.8%). FIR patients who underwent PB alone had a 5-year BFD of 98.1%. UIR patients were commonly treated with external beam radiotherapy plus PB (61.2%). These patients had 5-year BFD of 91.1%. The 5-year BFD for UIR patients treated without ADT was 90.9%, whereas it was 95.0% among UIR patients treated with ADT (log-rank p = 0.83).

CONCLUSIONS

FIR patients have excellent outcomes when treated with PB alone. External beam radiotherapy plus PB is a reasonable treatment approach for UIR patients. Future studies may elucidate which IR patients would benefit from treatment intensification.

Prostate cancer

The management of prostate cancer continues to evolve rapidly, with substantial advances being made in understanding the genomic landscape and biology underpinning both primary and metastatic prostate cancer. Similarly, the emergence of more sensitive imaging methods has improved diagnostic and staging accuracy and refined surveillance strategies. These advances have introduced personalised therapeutics to clinical practice, with treatments targeting genomic alterations in DNA repair pathways now clinically validated. An important shift in the therapeutic framework for metastatic disease has taken place, with metastatic-directed therapies being evaluated for oligometastatic disease, aggressive management of the primary lesion shown to benefit patients with low-volume metastatic disease, and with several novel androgen pathway inhibitors significantly improving survival when used as a first-line therapy for metastatic disease. Research into the molecular characterisation of localised, recurrent, and progressive disease will undoubtedly have an impact on clinical management. Similarly, emerging research into novel therapeutics, such as targeted radioisotopes and immunotherapy, holds much promise for improving the lives of patients with prostate cancer.

A Review on the Current Treatment Paradigm in High-Risk Prostate Cancer

High-risk prostate cancer is traditionally treated with a combination of radiotherapy (RT) and androgen deprivation therapy (ADT). However, recent advancements in systemic treatment and radiotherapy have widened the spectrum of treatment for this patient population. Use of image guidance and intensity modulation, as well as the incorporation of brachytherapy, has led to safe radiotherapy dose escalation with reduced risk of recurrence. Clinical trials have helped define the role of pelvic nodal radiotherapy, the role of stereotactic ablative radiotherapy, and the optimal duration and sequencing of ADT in combination with radiotherapy. Emerging evidence has redefined the role of surgery in this cohort. Contemporary clinical trials have identified new systemic therapy options in high-risk prostate cancer. Finally, new imaging modalities including multi-parametric MRI and molecular imaging and genomic classifiers have ushered a new era in patient selection, risk stratification, and treatment tailoring.

Radical prostatectomy versus external beam radiation therapy for high-grade, clinically localized prostate cancer: Emulation of a target clinical trial

PURPOSE

The comparative effectiveness of surgery and radiation therapy for high-grade, clinically localized prostate cancer remains a seminal, open question in urologic oncology, with no randomized controlled trials to inform management. We therefore emulated a hypothetical target clinical trial of radical prostatectomy (RP) versus external beam radiotherapy (EBRT) for high-grade, clinically localized prostate cancer.

MATERIALS AND METHODS

We conducted observational analyses using the National Cancer Database from 2006-2015 to emulate a target clinical trial in men 55-69 years with cT1-3cN0cM0, PSA<20 ng/mL, Gleason 8 to 10 prostate adenocarcinoma treated with RP or 75 to 81 Gy EBRT with androgen deprivation therapy (EBRT+ADT). The associations of treatment type with overall survival (OS) were estimated using Cox regression with stabilized inverse probability weights (IPW).

RESULTS

A total of 26,806 men formed the study cohort (RP: 23,990; EBRT+ADT: 2,816). Baseline characteristics were well-balanced after IPW-adjustment. Median follow-up was 48.4 (IQR 25.5-76.2) months. After IPW-reweighting, RP was associated with improved OS compared to EBRT+ADT (HR 0.54;95% CI 0.48-0.62; P<0.001), with 5- and 10-year OS of 93% vs 87%, and 76% vs 60%, respectively. RP was associated with improved OS across all categories of Gleason score, PSA, cT stage, age, and Charlson comorbidity index examined. In sensitivity analyses adjusting for biopsy tumor volume and a biopsy-specific Gleason score, RP remained associated with improved OS compared to EBRT+ADT (HR 0.62;95% CI 0.49-0.78; P<0.001).

CONCLUSIONS

In observational analyses designed to emulate a target clinical trial of men with high-grade, clinically localized prostate cancer, RP was associated with improved OS compared with EBRT+ADT.

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.

Moderately hypofractionated radiotherapy for localized prostate cancer: updated long-term outcome and toxicity analysis

PURPOSE

Evaluation of long-term outcome and toxicity of moderately hypofractionated radiotherapy using intensity-modulated radiotherapy (IMRT) with simultaneous integrated boost treatment planning and cone beam CT-based image guidance for localized prostate cancer.

METHODS

Between 2005 and 2015, 346 consecutive patients with localized prostate cancer received primary radiotherapy using cone beam CT-based image-guided intensity-modulated radiotherapy (IG-IMRT) and volumetric modulated arc therapy (IG-VMAT) with a simultaneous integrated boost (SIB). Total doses of 73.9 Gy (n = 44) and 76.2 Gy (n = 302) to the high-dose PTV were delivered in 32 and 33 fractions, respectively. The low-dose PTV received a dose (D95) of 60.06 Gy in single doses of 1.82 Gy. The pelvic lymph nodes were treated in 91 high-risk patients to 45.5 Gy (D95).

RESULTS

Median follow-up was 61.8 months. The 5‑year biochemical relapse-free survival (bRFS) was 85.4% for all patients and 93.3, 87.4, and 79.4% for low-, intermediate-, and high-risk disease, respectively. The 5‑year prostate cancer-specific survival (PSS) was 94.8% for all patients and 98.7, 98.9, 89.3% for low-, intermediate-, and high-risk disease, respectively. The 5‑year and 10-year overall survival rates were 83.8 and 66.3% and the 5‑year and 10-year freedom from distant metastasis rates were 92.2 and 88.0%, respectively. Cumulative 5‑year late GU toxicity and late GI toxicity grade ≥2 was observed in 26.3 and 12.1% of the patients, respectively. Cumulative 5‑year late grade 3 GU/GI toxicity occurred in 4.0/1.2%.

CONCLUSION

Moderately hypofractionated radiotherapy using SIB treatment planning and cone beam CT image guidance resulted in high biochemical control and survival with low rates of late toxicity.