The ProBio trial: molecular biomarkers for advancing personalized treatment decision in patients with metastatic castration-resistant prostate cancer

BACKGROUND

Multiple therapies exist for patients with metastatic castration-resistant prostate cancer (mCRPC). However, their improvement on progression-free survival (PFS) remains modest, potentially explained by tumor molecular heterogeneity. Several prognostic molecular biomarkers have been identified for mCRPC that may have predictive potential to guide treatment selection and prolong PFS. We designed a platform trial to test this hypothesis.

METHODS

The Prostate-Biomarker (ProBio) study is a multi-center, outcome-adaptive, multi-arm, biomarker-driven platform trial for tailoring treatment decisions for men with mCRPC. Treatment decisions in the experimental arms are based on biomarker signatures defined as mutations in certain genes/pathways suggested in the scientific literature to be important for treatment response in mCRPC. The biomarker signatures are determined by targeted sequencing of circulating tumor and germline DNA using a panel specifically designed for mCRPC.

DISCUSSION

Patients are stratified based on the sequencing results and randomized to either current clinical practice (control), where the treating physician decides treatment, or to molecularly driven treatment selection based on the biomarker profile. Outcome-adaptive randomization is implemented to early identify promising treatments for a biomarker signature. Biomarker signature-treatment combinations graduate from the platform when they demonstrate 85% probability of improving PFS compared to the control arm. Graduated combinations are further evaluated in a seamless confirmatory trial with fixed randomization. The platform design allows for new drugs and biomarkers to be introduced in the study.

CONCLUSIONS

The ProBio design allows promising treatment-biomarker combinations to quickly graduate from the platform and be confirmed for rapid implementation in clinical care.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier NCT03903835. Date of registration: April 4, 2019. Status: Recruiting.

Health-related quality of life overview after different curative treatment options in muscle-invasive bladder cancer: an umbrella review

PURPOSE

This umbrella review aims to evaluate the quality, summarize and compare the conclusions of systematic reviews investigating the impact of curative treatment options on health-related quality of life (HRQoL) in muscle-invasive bladder cancer (MIBC).

METHODS

The Cochrane Library, MEDLINE, Embase and Web of Science were searched independently by two authors from inception until 06 January 2020. Systematic reviews and meta-analyses assessing the impact of any curative treatment option on HRQol in MIBC patients were eligible. Risk of bias was assessed using the AMSTAR 2 tool.

RESULTS

Thirty-two reviews were included. Robot-assisted RC with extracorporeal urinary diversion and open RC have similar HRQoL (n = 10). Evidence for pelvic organ-sparing RC was too limited (n = 2). Patients with a neobladder showed better overall and physical HRQoL outcomes, but worse urinary function in comparison with ileal conduit (n = 17). Bladder-preserving radiochemotherapy showed slightly better urinary and sexual but worse gastro-intestinal HRQoL outcomes in comparison with RC patients (n = 6). Quality of the reviews was low in more than 50% of the available reviews and most of the studies included in the reviews were nonrandomized studies.

CONCLUSION

This umbrella review gives a comprehensive overview of the available evidence to date.

Phase II open-label study investigating apalutamide in patients with biochemical progression after radical prostatectomy

Apalutamide, a competent inhibitor of the androgen receptor, has shown promising clinical efficacy results for patients with advanced prostate cancer. Here, we describe the rationale and design for the SAVE trial, a multi-center, Phase II study, wherein 202 men with biochemical progression after radical prostatectomy are randomly assigned 1:1 to apalutamide plus salvage radiotherapy (SRT) or androgen-deprivation therapy with an luteinizing hormone-releasing hormone agonist or antagonist plus SRT. The primary objective is to compare sexual function between the two treatment arms based on the expanded prostate cancer index-26 sexual domain score at nine months after start of hormonal treatment. The key secondary objectives are to assess quality of life, to evaluate the safety profile and the short-term efficacy of apalutamide in combination with SRT. ClinicalTrials.gov identifier: NCT03899077.

PEACE V - Salvage Treatment of OligoRecurrent nodal prostate cancer Metastases (STORM): a study protocol for a randomized controlled phase II trial

BACKGROUND

Pelvic nodal recurrences are being increasingly diagnosed with the introduction of new molecular imaging techniques, like choline and PSMA PET-CT, in the restaging of recurrent prostate cancer (PCa). At this moment, there are no specific treatment recommendations for patients with limited nodal recurrences and different locoregional treatment approaches are currently being used, mostly by means of metastasis-directed therapies (MDT): salvage lymph node dissection (sLND) or stereotactic body radiotherapy (SBRT). Since the majority of patients treated with MDT relapse within 2 years in adjacent lymph node regions, with an estimated median time to progression of 12-18 months, combining MDT with whole pelvic radiotherapy (WPRT) may improve oncological outcomes in these patients. The aim of this prospective multicentre randomized controlled phase II trial is to assess the impact of the addition of WPRT to MDT and short-term androgen deprivation therapy (ADT) on metastasis-free survival (MFS) in the setting of oligorecurrent pelvic nodal recurrence.

METHODS & DESIGN

Patients diagnosed with PET-detected pelvic nodal oligorecurrence (≤5 nodes) following radical local treatment for PCa, will be randomized in a 1:1 ratio between arm A: MDT and 6 months of ADT, or arm B: WPRT added to MDT and 6 months of ADT. Patients will be stratified by type of PET-tracer (choline, FACBC or PSMA) and by type of MDT (sLND or SBRT). The primary endpoint is MFS and the secondary endpoints include clinical and biochemical progression-free survival (PFS), prostate cancer specific survival, quality of life (QoL), toxicity and time to castration-resistant prostate cancer (CRPC) and to palliative ADT. Estimated study completion: December 31, 2023.

DISCUSSION

This is the first prospective multicentre randomized phase II trial assessing the potential of combined WPRT and MDT as compared to MDT alone on MFS for patients with nodal oligorecurrent PCa.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT03569241, registered June 14, 2018, ; Identifier on Swiss National Clinical Trials Portal (SNCTP): SNCTP000002947, registered June 14, 2018.

External Validation of the 2019 Briganti Nomogram for the Identification of Prostate Cancer Patients Who Should Be Considered for an Extended Pelvic Lymph Node Dissection

The 2019 Briganti nomogram was developed to calculate the risk of lymph node invasion (LNI) and identify prostate cancer (PCa) patients diagnosed with magnetic resonance imaging (MRI)-targeted biopsy who should be considered for an extended pelvic lymph node dissection (ePLND). Since its implementation is still limited by lack of a formal external validation, we aimed to validate this tool in a large contemporary cohort. We identified 487 patients diagnosed using MRI-targeted with concomitant systematic biopsy who underwent radical prostatectomy (RP) and an anatomically defined ePLND at six centers. The external validity of the 2019 Briganti nomogram for estimating LNI risk was assessed via calibration, discrimination, and decision curve analyses (DCAs). A total of 38 (8%) patients had LNI at final pathology. The median number of nodes removed was 18 (interquartile range 14-24). On external validation, the 2019 Briganti nomogram had an area under the receiver operating characteristic curve (AUC) of 79%. Although there was some miscalibration, this was at predicted probabilities >35% and therefore outside the clinically relevant range. DCA demonstrated that the 2019 Briganti nomogram improved clinical risk prediction against LNI threshold probabilities of ≤30%. For a 7% cutoff, 273 (56%) ePLNDs would be spared and only 2.6% LNIs would be missed. The 2019 Briganti nomogram was characterized by higher AUC compared to the 2012 and 2017 Briganti nomograms and the Memorial Sloan Kettering Cancer Center risk calculator (79% vs 75% vs 65% vs 74%) and demonstrated the highest net benefit on DCA. This first multi-institutional validation of the 2019 Briganti nomogram in predicting LNI in PCa patients diagnosed with MRI-targeted biopsy confirms the highest AUC, better calibration and the highest net benefit compared with available tools and should be adopted to identify candidates for ePLND among men diagnosed with MRI-targeted biopsy. PATIENT SUMMARY: We performed the first multi-institutional validation of the first nomogram predicting lymph node invasion specifically developed using data from prostate cancer patients diagnosed with magnetic resonance imaging (MRI)-targeted biopsy. This nomogram exhibited excellent characteristics on external validation compared with available tools and should be adopted to identify candidates for extended pelvic lymph node dissection among men diagnosed with MRI-targeted biopsy.

Correction to: Metastasectomy for visceral and skeletal oligorecurrent prostate cancer

The authors have requested the removal of the Excel file in Electronic Supplementary Material to protect patient's privacy.

Unravelling the proteomic landscape of extracellular vesicles in prostate cancer by density-based fractionation of urine

Extracellular vesicles (EV) are increasingly being recognized as important vehicles of intercellular communication and promising diagnostic and prognostic biomarkers in cancer. Despite this enormous clinical potential, the plethora of methods to separate EV from biofluids, providing material of highly variable purity, and lacking knowledge regarding methodological repeatability pose a barrier to clinical translation. Urine is considered an ideal proximal fluid for the study of EV in urological cancers due to its direct contact with the urogenital system. We demonstrate that density-based fractionation of urine by bottom-up Optiprep density gradient centrifugation separates EV and soluble proteins with high specificity and repeatability. Mass spectrometry-based proteomic analysis of urinary EV (uEV) in men with benign and malignant prostate disease allowed us to significantly expand the known human uEV proteome with high specificity and identifies a unique biological profile in prostate cancer not uncovered by the analysis of soluble proteins. In addition, profiling the proteome of EV separated from prostate tumour conditioned medium and matched uEV confirms the specificity of the identified uEV proteome for prostate cancer. Finally, a comparative proteomic analysis with uEV from patients with bladder and renal cancer provided additional evidence of the selective enrichment of protein signatures in uEV reflecting their respective cancer tissues of origin. In conclusion, this study identifies hundreds of previously undetected proteins in uEV of prostate cancer patients and provides a powerful toolbox to map uEV content and contaminants ultimately allowing biomarker discovery in urological cancers.

Optimization of PET protocol and interrater reliability of 18F-PSMA-11 imaging of prostate cancer

BACKGROUND

Several scan parameters for PET imaging with 18F-PSMA-11 such as dosage, acquisition time and scan duration were evaluated to determine the most appropriate scan protocol, as well as the effect of furosemide administration on lesion visualization. Forty-four patients were randomly assigned to a dosage group (2.0 ± 0.2 or 4.0 ± 0.4 MBq/kg 18F-PSMA-11). All patients received a full-body PET/CT 1 h and 3 h after radiotracer injection with a scan duration of 3 min/bed position. For comparison of the scan duration, images were reconstructed for 1.5 and 3 min/bed position. Patients were intravenously administered 0.5 mg/kg furosemide with a maximum dose of 40 mg. To evaluate the furosemide effect, 22 additional patients were recruited and received one full-body PET/CT 1 h after administration of 2.0 ± 0.2 MBq/kg 18F-PSMA-11 with a scan duration of 3 min/bed position. To this group, no furosemide was administered. Images were scored on image quality using a 7-point scale and each suspicious lesion was described. To assess interrater reliability, two nuclear physicians scored all scans independently and described all observed suspicious lesions.

RESULTS

The 4 MBq/kg group received for all reconstructed images (60 min p.i., 1.5 and 3 min/bed position and 180 min p.i., 1.5 and 3 min/bed position) the highest median image quality score compared to the 2 MBq/kg group (p values < 0.01). When comparing all reconstructed images, the highest image quality score was given to images at 60 min p.i., 3 min/bed position for both dosage groups (score 5 and 6 for 2 and 4 MBq/kg, respectively). The addition of furosemide administration decreased the interference score with one point (p = 0.01106) and facilitated the evaluation of lesions in proximity to the ureters. The interrater reliability for the comparison of each lesion separately after more than 40 18F-PSMA-11 scan readings showed an increasing κ value from 0.78 (95% CI, 0.65-0.92) to 0.94 (95% CI, 0.87-1).

CONCLUSION

Although the results indicate an administered activity of 4.0 ± 0.4 MBq/kg, preference will be given to 2.0 ± 0.2 MBq/kg due to the small difference in absolute score (max 1 point) and the ALARA principle. For evaluation of lesions in proximity to the ureters, the co-administration of a diuretic can be useful. The increase of the κ value from 0.78 to 0.94 suggests a learning curve in the interpretation of 18F-PSMA-11 images.

TRIAL REGISTRATION

Clinicaltrials.gov, NCT03573011. Retrospectively registered 28 June 2018.

Surveillance or metastasis-directed therapy for oligometastatic prostate cancer recurrence (STOMP): Five-year results of a randomized phase II trial

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Background: Multiple randomized phase II trials suggest that metastasis-directed therapy (MDT) for oligometastatic prostate cancer (PCa) improves progression-free survival, but the majority of trials lack longer follow-up. We present the updated 5-year results from the STOMP-trial. Methods: In this multicentre, randomised, phase II study, asymptomatic PCa patients were eligible in case of a biochemical recurrence following primary PCa treatment with curative intent and presenting with up to 3 extracranial on choline PET-CT and a serum testosterone levels > 50 ng/ml. Patients were randomly assigned (1:1) to either surveillance or MDT of all detected lesions. Randomisation was balanced dynamically on two factors: PSA doubling time (≤3 vs. > 3 months) and nodal vs non-nodal metastases. The primary endpoint was androgen deprivation therapy (ADT)-free survival. Castrate resistant prostate cancer-free survival (CRPC) was a secondary endpoint. Tests were performed two-sided; p values less than 0.20 were deemed significant. Results: The 5-year ADT-free survival was 8% for the surveillance group and 34% for the MDT group (Figure 1, hazard ratio 0.57 [80% CI: 0.38-0.84], log-rank p = 0.06). There was no significant difference in effect for the different stratification factors (interaction test). The 5-year CRPC-free survival was 53% for the surveillance group and 76% for the MDT group (hazard ratio 0.62 [80% CI: 0.35−1.09]; log−rank p = 0.27). At a median follow for survival of 5.3 years (IQR 4.3-6.3), the 5-year overall survival was 85%, with 6 out of 14 deaths attributed to prostate cancer. Conclusions: The updated STOMP trial outcomes confirm the earlier reported significant difference in ADT free survival in favor of the MDT group compared to surveillance. Prostate-cancer related mortality is low within the first 5 years of diagnosis of oligorecurrent prostate cancer. Clinical trial information: NCT01558427.

Management of Patients with Advanced Prostate Cancer: Report of the Advanced Prostate Cancer Consensus Conference 2019

BACKGROUND

Innovations in treatments, imaging, and molecular characterisation in advanced prostate cancer have improved outcomes, but there are still many aspects of management that lack high-level evidence to inform clinical practice. The Advanced Prostate Cancer Consensus Conference (APCCC) 2019 addressed some of these topics to supplement guidelines that are based on level 1 evidence.

OBJECTIVE

To present the results from the APCCC 2019.

DESIGN, SETTING, AND PARTICIPANTS

Similar to prior conferences, experts identified 10 important areas of controversy regarding the management of advanced prostate cancer: locally advanced disease, biochemical recurrence after local therapy, treating the primary tumour in the metastatic setting, metastatic hormone-sensitive/naïve prostate cancer, nonmetastatic castration-resistant prostate cancer, metastatic castration-resistant prostate cancer, bone health and bone metastases, molecular characterisation of tissue and blood, inter- and intrapatient heterogeneity, and adverse effects of hormonal therapy and their management. A panel of 72 international prostate cancer experts developed the programme and the consensus questions.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

The panel voted publicly but anonymously on 123 predefined questions, which were developed by both voting and nonvoting panel members prior to the conference following a modified Delphi process.

RESULTS AND LIMITATIONS

Panellists voted based on their opinions rather than a standard literature review or formal meta-analysis. The answer options for the consensus questions had varying degrees of support by the panel, as reflected in this article and the detailed voting results reported in the Supplementary material.

CONCLUSIONS

These voting results from a panel of prostate cancer experts can help clinicians and patients navigate controversial areas of advanced prostate management for which high-level evidence is sparse. However, diagnostic and treatment decisions should always be individualised based on patient-specific factors, such as disease extent and location, prior lines of therapy, comorbidities, and treatment preferences, together with current and emerging clinical evidence and logistic and economic constraints. Clinical trial enrolment for men with advanced prostate cancer should be strongly encouraged. Importantly, APCCC 2019 once again identified important questions that merit assessment in specifically designed trials.

PATIENT SUMMARY

The Advanced Prostate Cancer Consensus Conference provides a forum to discuss and debate current diagnostic and treatment options for patients with advanced prostate cancer. The conference, which has been held three times since 2015, aims to share the knowledge of world experts in prostate cancer management with health care providers worldwide. At the end of the conference, an expert panel discusses and votes on predefined consensus questions that target the most clinically relevant areas of advanced prostate cancer treatment. The results of the voting provide a practical guide to help clinicians discuss therapeutic options with patients as part of shared and multidisciplinary decision making.

Characterisation and classification of oligometastatic disease: a European Society for Radiotherapy and Oncology and European Organisation for Research and Treatment of Cancer consensus recommendation

Oligometastatic disease has been proposed as an intermediate state between localised and systemically metastasised disease. In the absence of randomised phase 3 trials, early clinical studies show improved survival when radical local therapy is added to standard systemic therapy for oligometastatic disease. However, since no biomarker for the identification of patients with true oligometastatic disease is clinically available, the diagnosis of oligometastatic disease is based solely on imaging findings. A small number of metastases on imaging could represent different clinical scenarios, which are associated with different prognoses and might require different treatment strategies. 20 international experts including 19 members of the European Society for Radiotherapy and Oncology and European Organisation for Research and Treatment of Cancer OligoCare project developed a comprehensive system for characterisation and classification of oligometastatic disease. We first did a systematic review of the literature to identify inclusion and exclusion criteria of prospective interventional oligometastatic disease clinical trials. Next, we used a Delphi consensus process to select a total of 17 oligometastatic disease characterisation factors that should be assessed in all patients treated with radical local therapy for oligometastatic disease, both within and outside of clinical trials. Using a second round of the Delphi method, we established a decision tree for oligometastatic disease classification together with a nomenclature. We agreed oligometastatic disease as the overall umbrella term. A history of polymetastatic disease before diagnosis of oligometastatic disease was used as the criterion to differentiate between induced oligometastatic disease (previous history of polymetastatic disease) and genuine oligometastatic disease (no history of polymetastatic disease). We further subclassified genuine oligometastatic disease into repeat oligometastatic disease (previous history of oligometastatic disease) and de-novo oligometastatic disease (first time diagnosis of oligometastatic disease). In de-novo oligometastatic disease, we differentiated between synchronous and metachronous oligometastatic disease. We did a final subclassification into oligorecurrence, oligoprogression, and oligopersistence, considering whether oligometastatic disease is diagnosed during a treatment-free interval or during active systemic therapy and whether or not an oligometastatic lesion is progressing on current imaging. This oligometastatic disease classification and nomenclature needs to be prospectively evaluated by the OligoCare study.

Defining the Most Informative Intermediate Clinical Endpoints for Patients Treated with Salvage Radiotherapy for Prostate-specific Antigen Rise After Radical Prostatectomy

Intermediate clinical endpoints (ICEs) might aid in trial design and potentially expedite study results. However, little is known about the most informative ICE for patients receiving salvage radiation therapy (sRT) after radical prostatectomy. To investigate the most informative ICE for patients receiving sRT, we used a multi-institutional database encompassing patients treated at eight tertiary centers. Overall, 1301 men with node-negative disease who had not received any form of androgen deprivation therapy were identified. Associations of biochemical (BCR) and clinical recurrence (CR) within 1, 3, 5, and 7yr after surgery with the risk of overall mortality were evaluated using multivariable Cox regression analyses fitted at the landmark points of 1, 3, 5, and 7yr after sRT. The discriminative ability of each model for predicting overall survival (OS) was assessed using Harrell's c index. Median follow-up for survivors was 5.6yr (interquartile range 2.0-8.8). On multivariable analysis, progression to CR within 3yr from sRT (hazard ratio 4.19, 95% confidence interval 1.44-11.2; p= 0.008) was the most informative ICE for predicting OS (c index 0.78) compared to CR within 1, 5, and 7yr (c index 0.72, 0.75, and 0.71). In conclusion, progression to CR within 3yr after sRT, irrespective of the time of surgery, was the most informative ICE for prediction of OS. Our study is hypothesis-generating. If these results are confirmed in future prospective studies and surrogacy is met, this information could be applied for study design and could potentially expedite earlier release of results from ongoing randomized controlled trials. PATIENT SUMMARY: Clinical recurrence of prostate cancer within 3yr after salvage radiation therapy, irrespective of the time of radical prostatectomy, represents the most informative intermediate clinical endpoint for the prediction of overall survival. This information could be applied in the design of future studies and could potentially expedite earlier release of results from ongoing randomized controlled trials.

Abiraterone and spironolactone in prostate cancer: a combination to avoid

Objectives: Disease progression in metastatic castration-resistant prostate cancer (mCRPC) is dependent on androgen signaling. This case describes the complex adaptive androgen signaling mechanisms in mCRPC and illustrates that caution should be exercised when treating these patients with drugs influencing the androgen axis.Methods: Single case report and review of the literature.Results: We report the case of an 86-year-old man with mCRPC, treated with the secondary antihormonal agent abiraterone acetate. Following association of spironolactone to deal with symptoms related to mineralocorticoid excess, biochemical and radiographic disease progression occurred. Spironolactone was discontinued and 8 months after withdrawal, the patient continues to show a biochemical response to abiraterone.Conclusions: Although spironolactone generally exerts anti-androgenic effects, experimental evidence exists that it acts as an androgen receptor agonist in an androgen-depleted environment, capable of inducing prostate cancer proliferation. This is supported by the observations described in this case report. Therefore, spironolactone should be avoided in prostate cancer patients suffering from treatment-associated side effects of abiraterone.

Hereditary prostate cancer - Primetime for genetic testing?

Prostate cancer (PCa) remains the most common cancer in men. The proportion of all PCa attributable to high-risk hereditary factors has been estimated to 5-15%. Recent landmark discoveries in PCa genetics led to the identification of germline mutations/alterations (eg. BRCA1, BRCA2, ATM or HOXB13), single nucleotide polymorphisms or copy number variations associated with PCa incidence and progression. However, offering germline testing to men with an assumed hereditary component is currently controversial. In the present review article, we provide an overview about the epidemiology and the genetic basis of PCa predisposition and critically discuss the significance and consequence in the clinical routine. In addition, we give an overview about genetic tests and report latest findings from ongoing clinical studies. Lastly, we discuss the impact of genetic testing in personalized therapy in advanced stages of the disease.

Hyperbaric oxygen therapy for radiation cystitis after pelvic radiotherapy: Systematic review of the recent literature

The present study assessed the efficacy of hyperbaric oxygen therapy in reducing symptoms of radiation cystitis, a specific type of iatrogenic injury to the bladder, by systematic review of recent literature. The MEDLINE, Embase and Web of Science databases were searched using combinations of the terms "radiation," "cystitis" and "hyperbaric oxygen" to identify articles evaluating patients with radiation cystitis, treated with hyperbaric oxygen therapy. Only recent (≤10 years) original studies were included. Data were extracted and pooled in order to calculate descriptive weighted averages. Articles were evaluated on their level of evidence. A total of 20 papers were obtained, resulting in a cohort of 815 patients who were treated with hyperbaric oxygen therapy for radiation cystitis. Overall and complete response rates varied from 64.8% to 100% and 20% to 100%, respectively. The weighted average overall and complete response rates were 87.3% and 65.3%, respectively. Adverse events were observed in 9.6% of the patients, but permanent side-effects were rare. The most prominent limitations were high cost and low availability. Hyperbaric oxygen therapy is effective in the treatment of radiation-induced cystitis, with minimal adverse events, but low availability and high cost. At present, evidence is low; therefore, more prospective studies are required.

Metastasis-directed Therapy in Treating Nodal Oligorecurrent Prostate Cancer: A Multi-institutional Analysis Comparing the Outcome and Toxicity of Stereotactic Body Radiotherapy and Elective Nodal Radiotherapy

BACKGROUND

Stereotactic body radiotherapy (SBRT) and elective nodal radiotherapy (ENRT) are being investigated as metastasis-directed treatments in oligorecurrent prostate cancer (PC); however, comparative data are still lacking.

OBJECTIVE

To compare outcome and toxicity between both treatments. Primary endpoint was metastasis-free survival, adjusted for selected variables (aMFS).

DESIGN, SETTING, AND PARTICIPANTS

This was a multi-institutional, retrospective analysis of 506 (SBRT: 309, ENRT: 197) patients with hormone-sensitive nodal oligorecurrent PC (five or fewer lymph nodes (LNs; N1/M1a), treated between 2004 and 2017. Median follow-up was 36 mo (interquartile range 23-56).

INTERVENTION

SBRT was defined as a minimum of 5 Gy per fraction to each lesion with a maximum of 10 fractions. ENRT was defined as a minimum dose of 45 Gy in up to 25 fractions to the elective nodes, with or without a simultaneous boost to the suspicious node(s). The choice of radiotherapy (RT) was at the discretion of the treating physician, with treatments being unbalanced over the centers.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

In total, 506 patients from 15 different treatment centers were included. Primary treatment was radical prostatectomy, RT, or their combination. Nodal recurrences were detected by positron emission tomography/computer tomography (97%) or conventional imaging (3%). Descriptive statistics was used to summarize patient characteristics.

RESULTS AND LIMITATIONS

ENRT was associated with fewer nodal recurrences compared with SBRT (p < 0.001). In a multivariable analysis, patients with one LN at recurrence had longer aMFS after ENRT (hazard ratio: 0.50, 95% confidence interval 0.30-0.85, p = 0.009). Late toxicity was higher after ENRT compared with that after SBRT (16% vs. 5%, p < 0.01). Limitations include higher use of hormone therapy in the ENRT cohort and nonstandardized follow-up.

CONCLUSIONS

ENRT reduces the number of nodal recurrences as compared with SBRT, however at higher toxicity. Our findings hypothesize that ENRT should be preferred to SBRT in the treatment of nodal oligorecurrences. This hypothesis needs to be evaluated in a randomized trial.

PATIENT SUMMARY

This study investigated the difference between stereotactic and elective nodal radiotherapy in treating limited nodal metastatic prostate cancer. Nodal relapse was less frequent following elective nodal radiotherapy than following stereotactic body radiotherapy, and thus elective nodal radiotherapy might be the preferred treatment.