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

Oncological results and cancer control definition in focal therapy for Prostate Cancer: a systematic review

INTRODUCTION

Focal therapy (FT) is a promising alternative to whole-gland treatments for Localized Prostate Cancer. Ten different FT modalities have been described in literature. However, FT is not yet recommended by the International Guidelines, due to the lack of robust data on Oncological Outcomes. The objective of our Narrative Review is to evaluate the oncological profile of the available FT modalities and to offer a comprehensive overview of the definitions of Cancer Control for FT.

MATERIAL AND METHODS

Literature search was performed on 21st February 2023 using PubMed, EMBASE, and Scopus, following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement (PRISMA). Articles reporting whole gland-treatments were excluded. All articles reporting oncological outcomes were included.

RESULTS

One-hundred-twenty-four studies, reporting data on more than 8000 patients treated with FT, were included. Overall, 40 papers were on High Intensity Focal Ultrasound (HIFU), 24 on Focal Cryotherapy, 13 on Irreversible Electroporation (IRE), 11 on Focal brachytherapy, 10 on Focal Laser Ablation (FLA), 8 on Photo-Dynamic Therapy (PDT), 3 on Microwave ablation, 3 on Robotic Partial Prostatectomy, 2 on bipolar Radio Frequency Ablation (bRFA), 1 on Prostatic Artery Embolization (PAE) and 9 comparative papers. Overall, the Biochemical Recurrence (BCR) rate ranged from 0% (Focal Brachytherapy) to 67.5% (HIFU); the Salvage treatment rate ranged from 1% (IRE) to 54% (HIFU) considering re-treatment with FT and from 0% (Focal Brachytherapy) to 66.7% considering standard Radical Treatments. There is no univocal definition of Cancer Control, however the "Phoenix criteria" for BCR were the most commonly used.

CONCLUSIONS

FT is a promising alternative treatment for localized prostate cancer in terms of Oncological Outcomes, however there is a wide heterogeneity in the definition of cancer control, the reporting of oncological outcomes and a lack of high-quality clinical trials. Solid comparative studies with standard treatments and an unambiguous consensus on how to describe Cancer Control in the field of Focal Therapy are needed.

Rectal toxicity of 3-dimensional conformal radiation therapy following hydrogel spacer (Space OAR) injection for men with prostate cancer

Purpose

To evaluate whether hydrogel spacer injection, which increases the distance between the prostate and rectum, prior to local radiation therapy for prostate cancer reduces rectal and bladder toxicity.

Patients and methods

With institutional review board approval (05-004), we retrospectively reviewed rectal and bladder toxicity after local radiation therapy in patients with prostate cancer who were followed up for more than 1 year.

Results

We included 156 patients who had received local radiation therapy. Their ages ranged from 63 to 86 years, with an average of 75 years. Most patients were treated only on the prostate and seminal vesicles. All prostate sites were irradiated as follows: whole pelvis with prostate in 10 patients, whole pelvis with prostate and metastatic sites in six, and prostate and metastatic sites in eight. Radiation therapy (70-74 Gy) was performed for the prostate. Irradiation of 45-46.8 Gy was applied to whole pelvic and para-aortic lymph nodes, with 54-60 Gy applied to bone metastatic sites. In one case, stereotactic body radiation therapy (36 Gy) was performed for a sacral bone metastatic site. The hydrogel spacer was injected in 39 patients. Rectal toxicity was reported in 21 patients without (17.9%) and 3 patients with (7.7%) the hydrogel spacer. Bladder toxicity was reported in five patients without and only one patient with the hydrogel spacer.

Conclusion

Hydrogel spacer injection prior to local radiation therapy for prostate cancer reduces rectal radiation exposure, lowers the risk of rectal complications, and may be a promising method for boosting the irradiation dose in the future.

Role of enzalutamide in primary and recurrent non-metastatic hormone sensitive prostate cancer: a systematic review of prospective clinical trials

INTRODUCTION

Enzalutamide, a second-generation androgen receptor inhibitor, is indicated for the treatment of metastatic disease, as well as in the treatment of non-metastatic castration resistant prostate cancer (PCa). This systematic review aims to determine outcomes and toxicity in patients with non-metastatic castration sensitive prostate cancer (nmCSPC) treated with enzalutamide in the primary or salvage settings.

METHOD

We performed a systematic review focusing on the role of Enzalutamide in the treatment of nmCSPC, using the PubMed/Medline database. Articles focusing on androgen receptor inhibitors in nmCSPC were included, while articles discussing exclusively metastatic or castration-resistant PCa were excluded.

RESULTS

The initial search retrieved 401 articles, of which 15 underwent a thorough assessment for relevance. Ultimately, 12 studies with pertinent outcomes were meticulously examined. Among these, seven studies were dedicated to the investigation of enzalutamide in the primary setting, while the remaining five publications specifically addressed its use in salvage settings. Regardless of the treatment setting, our data revealed two distinct therapeutic strategies. The first advocates for the substitution of enzalutamide for androgen deprivation therapy (ADT), based on the premise of achieving equivalent, if not superior, oncological outcomes while minimizing treatment-related toxicity. The second, adopting a more conventional approach, entails augmenting the effectiveness of ADT by incorporating enzalutamide.

CONCLUSION

Enzalutamide has considerable potential as a therapeutic strategy for nmCSPC, either used alone or in combination with ADT in the primary or in the salvage settings. The use of enzalutamide instead of ADT is an appealing strategy. However, more trials will be required to further understand the efficacy and side-effect profile of enzalutamide monotherapy.

The expanding role of radiation oncology across the prostate cancer continuum

Radiotherapy is used in the treatment of prostate cancer in a variety of disease states with significant reliance on imaging to guide clinical decision-making and radiation delivery. In the definitive setting, the choice of radiotherapy treatment modality, dose, and fractionation for localized prostate cancer is determined by the patient's initial risk stratification and other clinical considerations. Radiation is also an option as salvage therapy in patients with locoregionally recurrent disease after prior definitive radiation or surgery. In recent years, the role of radiation has expanded for patients with metastatic disease, including prostate-directed radiotherapy in de novo low volume metastatic disease, metastasis-directed therapy for oligorecurrent disease, and palliative management of symptomatic metastases in the advanced setting. Here we review the expanding role of radiation in the treatment of prostate cancer in the definitive, locoregionally recurrent, and metastatic settings, as well as highlight the role of imaging in clinical reasoning, radiation planning, and treatment delivery.

Salvage Reirradiation for Locally Recurrent Prostate Cancer: Results From a Prospective Study With 7.2 Years of Follow-Up

PURPOSE

There are no well-established re-treatment options for local recurrence after primary curative radiation therapy for prostate cancer (PCa), as prospective studies with long-term follow-up are lacking. Here, we present results from a prospective study on focal salvage reirradiation with external-beam radiation therapy with a median follow-up of 7.2 years.

MATERIALS AND METHODS

From 2013 to 2017, 38 patients with biopsy-proven locally recurrent PCa >2 years after previous treatment and absence of grade 2-3 toxicity from the first course of radiation were included. The treatment was 35 Gy in five fractions to the MRI-based target volume and 6 months of androgen-deprivation therapy starting 3 months before radiation. The Phoenix criteria defined biochemical recurrence-free survival (bRFS), and toxicity was scored according to Radiation Therapy Oncology Group criteria.

RESULTS

Median age was 70 years, and median time from primary radiation to prostate-specific antigen (PSA) recurrence was 83 months. The actuarial 2-year and 5-year bRFS were 81% (95% CI, 69 to 94) and 58% (95% CI, 49 to 74), respectively. The actuarial 5-year local recurrence-free survival was 93% (95% CI, 82 to 100), metastasis-free survival was 82% (95% CI, 69 to 95), and overall survival was 87% (95% CI, 76 to 98). Two patients (5%) had durable grade 3 genitourinary toxicity, one combined with GI grade 3 toxicity. A PSA doubling time ≤6 months at salvage, a Gleason score >7, and a PSA nadir ≥0.1 ng/mL predicted a worse outcome.

CONCLUSION

Reirradiation with EBRT for locally recurrent PCa after primary curative radiation therapy is clinically feasible and demonstrated a favorable outcome with acceptable toxicity in this prospective study with long-term follow-up.

Initial management approach for localized/locally advanced disease is critical to guide metastatic castration-resistant prostate cancer care

BACKGROUND

Currently, several therapies are available for metastatic castration-resistant prostate cancer (mCRPC) but no specific clinical factors to personalize treatment. We first sought the prognostic value of duration on androgen-deprivation therapy (ADT) for hormone-sensitive prostate cancer (HSPC) in patients receiving androgen-receptor-signaling inhibitors (ARSI) for mCRPC.

METHODS

A multicenter cohort of mCRPC patients who started ARSI between July 2011 and October 2021 was identified. Based on their initial disease burden and duration on ADT for HSPC, primary progressive (PP) men were classified into four groups: low/intermediate-risk localized disease (LOC) and high-risk localized/locally advanced disease (LAD) and short-term (ST) < 24 vs. long-term (LT) ADT ≥ 24 months, whereas de novo (DN) mHSPC were subdivided into short-time vs. long-time to CRPC.

RESULTS

We included 919 mCRPC patients with a median age of 77 years [interquartile range (IQR) = 71-82)]. Median ADT duration in HSPC was 24 months (IQR = 14-40). Median follow-up was 91 months (IQR = 62-138), median OS and PFS from ARSI start were 20 (IQR 10-32) and 10 months (IQR = 5-19), respectively. In PP developing metastatic disease (n = 655, 71.3%), LOC and LAD with ST ADT had a greater than almost double-risk of death compared to LT ADT (LOC/ST: hazard ratio [HR] = 2.01; 95% CI 1.54-2.64; LAD/ST: HR = 1.73; 95% CI 1.34-2.24; p < 0.001). In the multivariate analysis including age, prognostic cohort, Gleason, ECOG, radical radiotherapy and prostatectomy, groups with ST ADT were associated with worse OS compared to LT ADT (LOC/ST: HR = 1.84; 95% CI 1.38-2.45; p < 0.001; LAD/ST: HR = 1.59; 95% CI 1.21-2.10; p < 0.001), along with ECOG > 2 (HR = 1.55; 95% CI 1.06-2.26; p = 0.03). There were also similar results of PFS. Moreover, long-time to CRPC in patients with history of DN mHSPC (n = 264, 28.7%) resulted in a better OS/PFS (HR = 0.76, 95% CI 0.56-1.02, p = 0.064 and HR = 0.74, 95% CI 0.55-0.99, p = 0.042, respectively).

CONCLUSIONS

Our study showed that duration on ADT for mHSPC was significantly associated with survival in mCRPC undergoing ARSI. These findings suggest a possible connection between initial management of prostate tumour and a better prognostication in mCRPC. Prospective trials are warranted.

ESTRO ACROP consensus recommendation on the target volume definition for radiation therapy of macroscopic prostate cancer recurrences after radical prostatectomy

Background

The European Society for Radiotherapy & Oncology (ESTRO) Advisory Committee for Radiation Oncology Practice (ACROP) panel on prostate bed delineation reflected on macroscopic local recurrences in patients referred for postoperative radiotherapy (PORT), a challenging situation without standardized approach, and decided to propose a consensus recommendation on target volume selection and definition.

Methods

An ESTRO ACROP contouring consensus panel consisting of 12 radiation oncologists and one radiologist, all with subspecialty expertise in prostate cancer, was established. Participants were asked to delineate the prostate bed clinical target volumes (CTVs) in two separate clinically relevant scenarios: a local recurrence at the seminal vesicle bed and one apically at the level of the anastomosis. Both recurrences were prostate-specific membrane antigen (PSMA)-avid and had an anatomical correlate on magnetic resonance imaging (MRI). Participants also answered case-specific questionnaires addressing detailed recommendations on target delineation. Discussions via electronic mails and videoconferences for final editing and consensus were performed.

Results

Contouring of the two cases confirmed considerable variation among the panelists. Finally, however, a consensus recommendation could be agreed upon. Firstly, it was proposed to always delineate the entire prostate bed as clinical target volume and not the local recurrence alone. The panel judged the risk of further microscopic disease outside of the visible recurrence too high to safely exclude the rest of the prostate bed from the CTV. A focused, "stereotactic" approach should be reserved for re-irradiation after previous PORT. Secondly, the option of a focal boost on the recurrence was discussed.

Conclusion

Radiation oncologists are increasingly confronted with macroscopic local recurrences visible on imaging in patients referred for postoperative radiotherapy. It was recommended to always delineate and irradiate the entire prostate bed, and not the local recurrence alone, whatever the exact location of that recurrence. Secondly, specific dose-escalation on the macroscopic recurrence should only be considered if an anatomic correlate is visible. Such a focal boost is probably feasible, provided that OAR constraints are prioritized. Possible dose is also dependent on the location of the recurrence. Its potential benefit should urgently be investigated in prospective clinical trials.

Long-term outcomes of whole-pelvis radiation therapy using volumetric modulated arc therapy for high-risk prostate cancer†

This study investigated the outcomes of whole-pelvis radiation therapy (WPRT) using volumetric modulated arc therapy (VMAT) for high-risk prostate cancer. We retrospectively analysed 112 patients with high-risk prostate cancer who started WPRT at our hospital between August 2011 and August 2015. The prescribed dose was 78 Gy in 39 fractions to the prostate and 46.8 Gy in 26 fractions to the pelvic lymph node (LN) area. All patients received long-term androgen deprivation therapy. We evaluated late gastrointestinal (GI) and genitourinary (GU) toxicities using the Common Terminology Criteria for Adverse Events version 4.0. The median follow-up period for censored cases was 97 (interquartile range [IQR] = 85-108) months. The median age was 72 (IQR = 67-75) years. The high-risk and very-high-risk groups included 41 (36.6%) and 71 patients (63.4%), respectively. The median risk of LN invasion calculated by the Roach formula was 36.9 (IQR = 26.6-56.3) %. The 8-year overall survival, biochemical failure-free survival, disease-free survival and distant metastasis-free survival rates were 88.4, 91.9, 83.8 and 98.0%, respectively. Only one patient experienced common iliac LN recurrence, which was outside the pelvic irradiation area. All patients with recurrent disease were categorized into the very-high-risk group. The 8-year cumulative rates of ≥Grade 2 late GI and GU toxicities were 12.8 and 11.8%, respectively. No patients experienced Grade 4 or higher toxicities. WPRT using VMAT for high-risk prostate cancer was well tolerated and effective.

Patterns of practice regarding use of radiation therapy following radical prostatectomy: A survey of Radiation Oncologists and Urologists in Australia and New Zealand

INTRODUCTION

This study aimed to investigate the patterns of practices of radiation oncologists (ROs) and urologists in Australia and New Zealand with respect to the utilisation of post-prostatectomy radiation therapy (RT) and help guide the development of an update to the existing Faculty of Radiation Oncology Genito-Urinary Group post-prostatectomy guidelines.

METHODS

ROs and urologists with subspecialty practice in prostate cancer from Australia and New Zealand were invited to participate in an online survey comprised of clinical scenarios regarding post-prostatectomy RT.

RESULTS

Sixty-five ROs and 28 urologists responded to the survey. In the setting of low-risk biochemical relapse, the threshold for initiating RT was lower for ROs than urologists. ROs were more likely than urologists to recommend adjuvant RT for node-positive disease. When salvage RT was advised for a pT3N0R1 recurrence, there was no consensus amongst ROs on whether to add either ADT or nodal treatment over prostate bed RT alone. For a solitary PSMA-avid pelvic lymph node recurrence, whole pelvis RT with androgen deprivation therapy was the preferred treatment option (72% ROs, 43% urologists). Most ROs (92%) recommended conventionally fractionated RT to 66-70 Gy, with a boost to any PSMA PET avid recurrent disease.

CONCLUSION

This survey highlights the marked discordance in practice for the management of prostate cancer relapse post-prostatectomy. This is seen not only between specialties but also within the radiation oncology community. This emphasises the need for an updated evidence-based guideline to be produced.