Assessing the Role and Optimal Duration of Hormonal Treatment in Association with Salvage Radiation Therapy After Radical Prostatectomy: Results from a Multi-Institutional Study

How the Management of Biochemical Recurrence in Prostate Cancer Will Be Modified by the Concept of Anticipation and Incrementation of Therapy

Biochemical recurrence (BCR) after primary treatments for prostate cancer (PC) is an extremely heterogeneous phase and at least a stratification into low- and high-risk cases for early progression in metastatic disease is necessary. At present, PSA-DT represents the best parameter to define low- and high-risk BCR PC, but real precision medicine is strongly suggested to define tailored management for patients with BCR. Before defining management, it is necessary to exclude the presence of low-volume metastasis associated with PSA progression using new-generation imaging, preferably with PSMA PET/CT. Low-risk BCR cases should be actively observed without early systemic therapies. Early treatment of low-risk BCR with continuous androgen deprivation therapy (ADT) can produce disadvantages such as the development of castration resistance before the appearance of metastases (non-metastatic castration-resistant PC). Patients with high-risk BCR benefit from early systemic therapy. Even with overall survival (OS) as the primary treatment endpoint, metastasis-free survival (MFS) should be used as a surrogate endpoint in clinical trials, especially in long survival stages of the disease. The EMBARK study has greatly influenced the management of high-risk BCR, by introducing the concept of anticipation and intensification through the use of androgen receptor signaling inhibitors (ARSIs) and ADT combination therapy. In high-risk (PSA-DT ≤ 9 months) BCR cases, the combination of enzalutamide with leuprolide significantly improves MFS when compared to leuprolide alone, maintaining an unchanged quality of life in the asymptomatic phase of the disease. The possibility of using ARSIs alone in this early disease setting is suggested by the EMBARK study (arm with enzalutamide alone) with less evidence than with the intensification of the combination therapy. Continued use versus discontinuation of enzalutamide plus leuprolide intensified therapy upon reaching undetectable PSA levels needs to be better defined with further analysis. Real-world analysis must verify the significant results obtained in the context of a phase 3 study.

Timing of Early Salvage Therapy for Patients With Biochemical Relapse of Prostate Carcinoma

Between 25% and 33% of patients after radical prostatectomy experience a relapse of the disease. The risk of relapse increases in patients with risk factors up to 50%-80%. For a long time, adjuvant radiotherapy has been considered the standard of care. Four large prospective trials, that compared adjuvant and salvage radiotherapy in patients with biochemical relapse, showed the superiority of the adjuvant approach in biochemical and local relapse-free survival, but no consistent benefit in long-term endpoints (i.e., metastasis-free survival, overall survival, or carcinoma-specific survival) at the expense of increased urinary and bowel toxicity. Three large international studies comparing adjuvant and salvage radiotherapy paved the way toward early salvage radiotherapy. However, the optimal threshold of the PSA level (range of 0.2-0.5 ng/mL) for initiating early salvage radiotherapy remains unresolved and still poses a challenge in everyday clinical practice when balancing the need for early radiotherapy and the associated toxicity. Imprecise stratification of biochemical relaps patients according to the risk of clinical relapse drives efforts to find additional molecular biomarkers that would improve the timing of the salvage therapy.

Androgen deprivation therapy in localized prostate cancer. Current status and future trends

INTRODUCTION

Prostate cancer (PCa) has been recognized as an androgen-sensitive disease since the investigations from Huggins and Hodges in 1941. Thanks to these findings, they received the Nobel Prize in 1966. This was the beginning of the development of androgen deprivation therapy (ADT) as treatment for patients with PCa.

OBJECTIVE

To summarize the current indications of ADT in localized PCa.

EVIDENCE ACQUISITION

We conducted a comprehensive English and Spanish language literature research, focused on the main indications for ADT in localized PCa.

EVIDENCE SYNTHESIS

Nowadays, the indications for ADT as monotherapy in localized PCa have been limited to specific situations, to patients unwilling or unable to receive any form of local treatment if they have a PSA-DT < 12 months, and either a PSA > 50 ng/mL, a poorly differentiated tumor, or troublesome local disease-related symptoms. ADT can be used in combination with local treatment in different scenarios. Although neoadjuvant treatment with ADT prior to surgery with curative intent has no clear oncological impact, as a future sight, PCa is a heterogeneous disease, and there could be a group of patients with high-risk localized disease that could benefit.

CONCLUSIONS

We need to optimize the treatment with ADT in localized PCa, selecting the patients accordingly to their disease characteristics. Given that the therapeutic armamentarium evolves day by day, there is a need for the development of new clinical trials, as well as a molecular studies of patients to identify those who might benefit from an early multimodal treatment.

Radiation Therapy After Radical Prostatectomy: What Has Changed Over Time?

The role and timing of radiotherapy (RT) in prostate cancer (PCa) patients treated with radical prostatectomy (RP) remains controversial. While recent trials support the oncological safety of early salvage RT (SRT) compared to adjuvant RT (ART) in selected patients, previous randomized studies demonstrated that ART might improve recurrence-free survival in patients at high risk for local recurrence based on adverse pathology. Although ART might improve survival, this approach is characterized by a risk of overtreatment in up to 40% of cases. SRT is defined as the administration of RT to the prostatic bed and to the surrounding tissues in the patient with PSA recurrence after surgery but no evidence of distant metastatic disease. The delivery of salvage therapies exclusively in men who experience biochemical recurrence (BCR) has the potential advantage of reducing the risk of side effects without theoretically compromising outcomes. However, how to select patients at risk of progression who are more likely to benefit from a more aggressive treatment after RP, the exact timing of RT after RP, and the use of hormone therapy and its duration at the time of RT are still open issues. Moreover, what the role of novel imaging techniques and genomic classifiers are in identifying the most optimal post-operative management of PCa patients treated with RP is yet to be clarified. This narrative review summarizes most relevant published data to guide a multidisciplinary team in selecting appropriate candidates for post-prostatectomy radiation therapy.

Using CT-guided stereotactic prostate radiation therapy (CT-SPRT) to assess sustained murine prostate ablation

The prostate is a hormone-responsive organ where testicular androgens drive the proliferation and survival of prostatic cells, ensuring the development and functioning of this gland throughout life. Androgen deprivation therapy leads to apoptosis of prostatic cells and organ regression, and is a cornerstone of prostate cancer and benign prostatic hypertrophy treatment. For several decades, androgen deprivation has been used as an adjuvant to external beam radiotherapy, however, emerging data suggests that the low rates of epithelial proliferation in the castrated prostate imparts radio-resistance. As proliferating cells exhibit increased sensitivity to radiation, we hypothesized that short bursts of synchronized epithelial proliferation, which can be achieved by exogeneous testosterone supplementation prior to targeted high-dose radiation, would maximize sustained prostate ablation, while minimizing damage to surrounding tissues. To test this hypothesis, we designed a novel computed-tomography (CT)-guided stereotactic prostate radiation therapy (CT-SPRT) technique to deliver a single high-dose 25 Gy fraction of X-ray radiation. Sustained prostatic cell ablation was assessed post CT-SPRT by measuring prostate weight, epithelial cell number, and relative contributions of luminal and basal epithelial populations in control and testosterone-pretreated glands. CT-SPRT was safely delivered with no observed damage to surrounding rectal and bladder tissues. Importantly, castrated mice that received a pulse of testosterone to induce synchronous cell proliferation prior to CT-SPRT exhibited significant sustained gland ablation compared to control mice. These results provide new insights in stereotactic radiotherapy sensitivity to maximize prostatic cell ablation and improve our understanding of prostate gland regeneration that can potentially lead to improved non-invasive therapies for benign prostatic hypertrophy and prostate cancer.

High-Risk Prostate Cancer: A Very Challenging Disease in the Field of Uro-Oncology

Prostate cancer (PCa) is the most common cancer in males and affects 16% of men during their lifetime [...].

Current and emerging therapies for localized high-risk prostate cancer

Introduction: Despite progress in the field of high-risk localized prostate cancer (HRPCa) treatments, high-risk patients treated with curative intent are at increased risk of biochemical recurrence, metastatic progression and cancer-related death. The optimal treatment strategy remains a topic of debate. This review provides an overview of the current and investigational therapeutic options for HRPCa.Areas covered: A PubMed search was performed for papers on the current perspectives on the multimodality treatment of HRPCa. We focus on both primary local treatment as well as systemic treatment options. Finally, relevant ongoing trials focusing on systemic treatments (including [neo]adjuvant treatments) enrolling at least 50 patients were retrieved, to highlight ongoing research and treatment optimization.Expert opinion: Disease progression in HRPCa patients is driven by local tumor extension and subclinical metastases. Therefore, the main treatment concept is a multimodal approach targeting the primary tumor with extended surgery or RT with long-term ADT and simultaneously targeting micro-metastatic deposits. However, there is still room for optimization. Upcoming clinical trials comparing surgery versus RT as local treatment, trials with (neo)adjuvant chemotherapy or androgen receptor signaling inhibitors will likely change the treatment landscape. However, a multimodal treatment strategy will stay as the cornerstone in the treatment of HRPCa.

Salvage Radiotherapy for Prostate Cancer

For patients experiencing biochemical recurrence in the absence of distant metastasis, salvage radiotherapy (SRT) with or without androgen deprivation therapy (ADT) is currently the only possible curative treatment option. Prostate-specific antigen (PSA) monitoring and the selected use of SRT has some advantages when compared with adjuvant radiotherapy. The most important one is avoidance of a potential overtreatment of patients who would never have disease progression, even in the presence of high-risk pathological features. The identification of a specific PSA cut-off seems to be incorrect. In patients with more adverse pathological features, early SRT administered at the very first sign of a PSA rise granted better disease control. Dose-intensified SRT is feasible and well tolerated with no significant difference in grade 2 or more acute and late toxicity. At least 66 Gy must be given in the salvage setting. ADT has a radio-sensitising effect on the radiotherapy by inhibiting the repair of DNA double-strand breaks. The use of ADT in the salvage setting results in a better oncological outcome. Hormonal therapy is associated with a decrease in quality of life and side-effects depending on the duration of hormone therapy. The oncological benefit of hormone therapy duration depends on their clinical and pathological characteristics. 68-Ga-prostate-specific membrane antigen positron emission tomography-computed tomography is the gold standard in staging prostate cancer patients with biochemical persistence or recurrence after radical prostatectomy. The implementation of 18F-labelled PSMA tracers can provide a further improvement.

EAU-EANM-ESTRO-ESUR-SIOG Guidelines on Prostate Cancer. Part II-2020 Update: Treatment of Relapsing and Metastatic Prostate Cancer

OBJECTIVE

To present a summary of the 2020 version of the European Association of Urology (EAU)-European Association of Nuclear Medicine (EANM)-European Society for Radiotherapy & Oncology (ESTRO)-European Society of Urogenital Radiology (ESUR)-International Society of Geriatric Oncology (SIOG) guidelines on the treatment of relapsing, metastatic, and castration-resistant prostate cancer (CRPC).

EVIDENCE ACQUISITION

The working panel performed a literature review of the new data (2016-2019). The guidelines were updated, and the levels of evidence and/or grades of recommendation were added based on a systematic review of the literature.

EVIDENCE SYNTHESIS

Prostate-specific membrane antigen positron emission tomography computed tomography scanning has developed an increasingly important role in men with biochemical recurrence after local therapy. Early salvage radiotherapy after radical prostatectomy appears as effective as adjuvant radiotherapy and, in a subset of patients, should be combined with androgen deprivation. New treatments have become available for men with metastatic hormone-sensitive prostate cancer (PCa), nonmetastatic CRPC, and metastatic CRPC, along with a role for local radiotherapy in men with low-volume metastatic hormone-sensitive PCa. Also included is information on quality of life outcomes in men with PCa.

CONCLUSIONS

The knowledge in the field of advanced and metastatic PCa and CRPC is changing rapidly. The 2020 EAU-EANM-ESTRO-ESUR-SIOG guidelines on PCa summarise the most recent findings and advice for use in clinical practice. These PCa guidelines are first endorsed by the EANM and reflect the multidisciplinary nature of PCa management. A full version is available from the EAU office or online (http://uroweb.org/guideline/prostate-cancer/).

PATIENT SUMMARY

This article summarises the guidelines for the treatment of relapsing, metastatic, and castration-resistant prostate cancer. These guidelines are evidence based and guide the clinician in the discussion with the patient on the treatment decisions to be taken. These guidelines are updated every year; this summary spans the 2017-2020 period of new evidence.

Lead-time bias does not falsify the efficacy of early salvage radiotherapy for recurrent prostate cancer

BACKGROUND

In prostate cancer (PCa) recurring after radical prostatectomy (RP), salvage radiotherapy (SRT) is recommended to be given at PSA <0.5 ng/ml. It has been speculated, that the advantage from early SRT is mainly caused by lead-time bias: Calculating from time of SRT, earlier treatment would per-se result in longer time to event/censoring compared with later treatment, but not extend the interval from RP to post-SRT failure.

METHODS

In 603 consecutive PCa patients receiving SRT between 1997 and 2017, we compared outcomes, calculating from time of irradiation vs. time of surgery.

RESULTS

In multivariable analysis, tumor stage pT3-4, pathological Gleason score GS ≤6 vs. GS 7 vs. GS ≥8, post-RP PSA persistence (nadir ≥0.1 ng/ml), and the pre-SRT PSA (continuous or with cutoff 0.4 ng/ml) were significant risk-factors for biochemical progression (BCR) and progression-free survival (PFS) post-SRT and post-RP. A pre-SRT PSA <0.4 ng/ml was a significant discriminator for Kaplan-Meier rates of BCR and PFS. The Cox model for overall survival (OS) included age at RP (continuous), pT2 vs. pT3-4, and pre-SRT PSA (continuous) as significant predictors. However, no significant cutoff for the pre-SRT PSA could be identified to differentiate Kaplan-Meier estimates of OS, possibly because there were too few events, as 88% of the patients were still alive at last follow-up.

CONCLUSIONS

The pre-SRT PSA has a significant impact on BCR, PFS and potentially on OS, calculating either from RP or from SRT to event/censoring, respectively. This contradicts the hypothesis of lead-time bias falsifying the advantage from early SRT.

Long- versus short-term androgen deprivation therapy with high-dose radiotherapy for biochemical failure after radical prostatectomy: a randomized controlled trial

Radical prostatectomy is a well-established treatment option in the management of localized and locally advanced prostate cancer. An extended lymphadenectomy is performed in case of substantial risk for lymph node involvement. When biochemical recurrence (BCR) occurs, salvage radiotherapy (SRT) is performed. The benefit in terms of BCR-free survival (FS) and metastasis-FS by adding 6 months of androgen deprivation therapy (ADT) compared with SRT only has already been established. Retrospective evidence suggests that a longer schedule of ADT may be more beneficial compared with 6 months. This multicenter open-label randomized trial will include patients who need SRT after experiencing BCR post-radical prostatectomy with lymphadenectomy and pN0-status. Patients will be randomized for ADT duration (6 vs 24 months). Primary end point is distant metastasis-FS.

Clinical Trial Registration: NCT04242017 ( ClinicalTrials.gov )