Metastasis-free survival is associated with overall survival in men with PSA-recurrent prostate cancer treated with deferred androgen deprivation therapy

Stereotactic ablative radiation therapy in metastatic prostate cancer

PURPOSE OF REVIEW

The evolving role of stereotactic ablative radiation therapy (SABR) as metastasis-directed therapy (MDT) for oligometastatic prostate cancer (omPCa) will be discussed.

RECENT FINDINGS

Oligometastatic disease (OMD) is an intermediate state between localized and wide-spread malignant disease. OMD has recently been spotlighted given the increasing demonstration of clinical benefit from local therapies despite presence of metastatic disease and allure of the curative potential of MDT in select cases. Among the different forms of MDT, SABR has rapidly become a widely adopted treatment modality. Significant efforts in this space have focused on omPCa, owing to its relatively indolent biology, presence of a sensitive and specific serum biomarker and recent advances in molecular imaging. While most studies have evaluated the role of SABR MDT in hormone sensitive omPCa, new emerging clinical data also suggests benefits of SABR MDT for even castration-resistant disease.

SUMMARY

Treating omPCa with SABR MDT appears to generate an efficacy signal with minimal morbidity across both hormone-sensitive and castration-resistant disease. However, additional definitive omPCa trial data are needed. Future research efforts should investigate biomarkers for this heterogeneous disease space and the role of SABR MDT in combination with systemic agents to improve upon standard of care treatments.

Randomized phase II trial in Prostate cancer with hormone-sensitive OligometaSTatic relapse: Combining stereotactic Ablative Radiotherapy and Durvalumab (POSTCARD GETUG P13): study protocol

Background

As in other solid tumors, increasing evidence indicates that patients diagnosed with a limited number of prostate cancer metastases, so-called oligometastases, have a better prognosis than patients with extensive metastatic disease. Stereotactic body radiotherapy (SBRT) is now considered an option in this population.Programmed death-1 (PD-1) and its ligands (PD-L1) are targeted by immune checkpoint inhibitors. Preclinical studies have shown that the tumor immune microenvironment changes when combining radiotherapy with immunotherapy, especially with hypofractionated radiotherapy.The oligometastatic setting appears to be the most relevant clinical situation for evaluating the immune response generated by radiotherapy and immune checkpoint inhibitors in patients with an intact immune system.We hypothesize that durvalumab will enhance the immune response following SBRT targeting oligometastatic lesions. Our purpose is to demonstrate, via a randomized 2:1 phase II trial, that SBRT (3 fractions) with durvalumab in oligometastatic hormone-sensitive prostate cancer patients would improve progression-free survival in patients with prostate cancer with up to 5 metastases compared to patients who exclusively received SBRT.

Methods

This is a multicentric randomized phase II study in French academic hospitals. Patients with prostate cancer and up to 5 metastases (lymph node and/or bone) were randomized into a 2:1 ratio between Arm A (experimental group), corresponding to durvalumab and SBRT to the metastases, and Arm B (control group), corresponding to SBRT alone to the metastases. The study aims to accrue a total of 96 patients within 3 years. The primary endpoint is two-year progression-free survival and secondary endpoints include androgen deprivation therapy-free survival, quality of life, toxicity, prostate cancer specific survival, overall survival, and immune response.

Discussion

The expected benefit for the patients in the experimental arm is longer life expectancy with acceptable toxicity. We also expect our study to provide data for better understanding the synergy between immunotherapy and radiotherapy in oligometastatic prostate cancer.

SPARKLE: a new spark in treating oligorecurrent prostate cancer: adding systemic treatment to stereotactic body radiotherapy or metastasectomy: key to long-lasting event-free survival?

BACKGROUND

Metastasis-directed therapy (MDT) significantly delays the initiation of palliative androgen deprivation therapy (pADT) in patients with oligorecurrent prostate cancer (PCa) with a positive impact on patient's quality of life. However, it remains unclear whether the addition of ADT improves polymetastatic free survival (PMFS) and metastatic castration refractory PCa-free survival (mCRPC-FS) and how long concomitant hormone therapy should be given. A significant overall survival (OS) benefit was shown when an androgen receptor targeted agent (ARTA) was added to pADT in patients with metastatic hormone sensitive PCa (HSPC). However, whether the addition of and ARTA to MDT in the treatment of oligorecurrent PCa results in better PMFS and mCRPC-FS has not been proven yet.

METHODS & DESIGN

Patients diagnosed with oligorecurrent HSPC (defined as a maximum of 5 extracranial metastases on PSMA PET-CT) will be randomized in a 1:1:1 allocation ratio between arm A: MDT alone, arm B: MDT with 1 month ADT, or arm C: MDT with 6 months ADT together with ARTA (enzalutamide 4 × 40 mg daily) for 6 months. Patients will be stratified by PSA doubling time (≤ 3 vs. > 3 months), number of metastases (1 vs. > 1) and initial localization of metastases (M1a vs. M1b and/or M1c). The primary endpoint is PMFS, and the secondary endpoints include mCRPC-FS, biochemical relapse-free survival (bRFS), clinical progression free survival (cPFS), cancer specific survival (CSS), overall survival (OS), quality of life (QOL) and toxicity.

DISCUSSION

This is the first prospective multicentre randomized phase III trial that investigates whether the addition of short-term ADT during 1 month or short-term ADT during 6 months together with an ARTA to MDT significantly prolongs PMFS and/or mCRPC-FS.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT05352178, registered April 28, 2022.

Oligometastatic disease in biochemical recurrence of prostate cancer: Prevalence on PSMA PET/CT and consecutive metastasis-directed therapy - Experience at a tertiary referral center

AIM

The aim of our study was to address the prevalence of oligometastatic recurrent prostate cancer (PCa) on PSMA-PET and the associated practice of metastasis-directed therapy (MDT). Next, we aimed to determine a PSA threshold below which most patients had local and/or oligometastatic recurrence on PSMA-PET.

METHODS

One hundred and ten consecutive patients with biochemical recurrence (BCR) after radical prostatectomy (RP) ± radiation were referred for ⁶⁸Ga-PSMA-11 or ¹⁸F-DCFPyL PET/CT. We correlated the location and number of PSMA-positive lesions against the treatment choice after imaging. Detection rates were stratified by PSA levels at the time of PET/CT. The study design was monocentric retrospective.

RESULTS

Thirty-four patients (30.9%) had a PSMA-negative scan, while 17 (15.5%) had local recurrence and 59 (53.6%) had metastatic recurrence on PSMA-PET. ROC analysis revealed a cut-off of ≤3 metastatic lesions on PSMA-PET for the steering of treatment decisions towards MDT rather than solely systemic therapy (AUC: 0.88). Defined as 3 or fewer metastatic lesions, oligometastatic recurrent PCa was found in up to 30% (33/110) of all patients. At PSA levels below 3.5 ng/ml, the rate of PSMA-positive disease that was locally confined or oligometastatic was 76% (45/59), dropping significantly to 29.4% (5/17) above this threshold (p<0.001) as polymetastatic findings became more frequent.

CONCLUSION

The detection of ≤3 oligometastases on PSMA-PET encouraged the consecutive pursuit of MDT instead of systemic therapy alone. PSMA-PET predominantly captured patients at recurrence stages amenable to localized treatment when initiated at PSA levels below 3.5 ng/ml.

Brachytherapy for oligometastatic prostate cancer to the penis

The origin of penile metastases is in 70% of cases from primary pelvic cancers (genitourinary and recto-sigmoid primary tumors). The prognosis is poor and it is often associated with synchronous bone metastases at the time of diagnosis. We present the case of a 61-year-old patient who developed a penile induration 7 years after radical prostatectomy followed by adjuvant external beam radiation therapy for high-risk prostatic adenocarcinoma. Biopsies confirmed the metastatic localization and a detailed assessment failed to find any further remote lesions. Faced with this penile oligometastatic prostate cancer, we proposed an ablative treatment based on interstitial multi-catheter high-dose rate brachytherapy. At the six-month follow-up, clinical examination and ⁶⁸Ga-PSMA-11-PET confirmed a complete response of the penile tumor without new lesion at a distance.

Local Therapies in Oligometastatic and Oligoprogressive Prostate Cancer

Oligometastatic disease was originally defined by Hellman and Weichselbaum as an intermediate-state existing between locally confined and widely disseminated malignancy, whose natural history could be positively impacted with systemic and importantly local therapies such as radiation. Currently oligometastatic prostate cancer (OPCa) is defined clinically by lesion enumeration and several subgroups exist: de novo (synchronous) oligometastatic disease present at initial diagnosis, oligorecurrent (metachronous) disease arising after definitive therapy to the prostate, and oligoprogressive disease where isolated lesions progress in a background of otherwise stable disease. In this review we highlight current knowledge and the potential future of local therapies, such as radiation to the primary prostate and metastasis-directed therapy (MDT), in the disease management of OPCa for all 3 subgroups. In addition, we examine more recent studies classifying the patterns of failure and natural history of OPCa following treatment with local therapies. Finally, while current clinical definitions of OPCa dominate, we introduce studies attempting to elucidate a more biological definition of OPCa to allow for improved selection of patients to treat with local therapies and to better inform precision combination approaches with systemic therapy.

Radical prostatectomy for localized prostate cancer: 20-year oncological outcomes from a German high-volume center

INTRODUCTION

Long-term outcomes of prostate cancer (CaP) patients treated with radical prostatectomy (RP) from European cohorts are under-reported. We report on 22,843 RP patients from the Martini-Klinik Prostate Cancer Centre treated between 1992 and 2017.

PATIENTS AND METHODS

Biochemical recurrence (BCR) free survival, metastasis free survival (MFS), and cancer specific survival (CSS) were stratified according to National Comprehensive Cancer Network (NCCN) risk categories, pT, and pN stages, RP Gleason Grade Groups (GGG), and surgical margin status (R0/R1). For time to event analyses, uni- and multivariable Cox's proportional hazards models and univariable Kaplan-Meier analyses were applied.

RESULTS

Median follow up was 68 months. Most favourable 20-year survival rates were exhibited in NCCN low risk (78.7% BCR-free, 96.8% MFS, 90.1% CSS) and pT2, GGG 1 to 2, R0 patients (83.1% BCR-free, 96.7% MFS, 92.6% CSS). 20-year follow up was not constantly reached in patients with aggressive CaP features. For example, NCCN very high-risk patients exhibited 15-year BCR-free survival of 30.5%, while 20-year MFS and CSS in these individuals was reached (64.1% and 60.8%, respectively). Lowest 10-year BCR-free survival (35.6%) was exhibited in pT3b, GGG 4 to 5, R0. Lowest 10-year MFS (49.5%) was exhibited in pT2, GGG 4 to 5, R1. Lowest 10-year CSS (69.8%) was exhibited in pT3b, GGG 4 to 5, R1 patients. In separate pN1 analyses, lowest 10-year BCR-free survival (14.5%), MFS (56.9%), and CSS (71.9%) were exhibited in patients with 3 or more positive lymph nodes.

CONCLUSION

Oncological outcomes after RP can be excellent for individuals with favorable CaP characteristics, also after 20 years of follow up.

Elevated Expression of Glycerol-3-Phosphate Phosphatase as a Biomarker of Poor Prognosis and Aggressive Prostate Cancer

The limitations of the biomarker prostate-specific antigen (PSA) necessitate the pursuit of biomarkers capable of better identifying high-risk prostate cancer (PC) patients in order to improve their therapeutic management and outcomes. Aggressive prostate tumors characteristically exhibit high rates of glycolysis and lipogenesis. Glycerol 3-phosphate phosphatase (G3PP), also known as phosphoglycolate phosphatase (PGP), is a recently identified mammalian enzyme, shown to play a role in the regulation of glucose metabolism, lipogenesis, lipolysis, and cellular nutrient-excess detoxification. We hypothesized that G3PP may relieve metabolic stress in cancer cells and assessed the association of its expression with PC patient prognosis. Using immunohistochemical staining, we assessed the epithelial expression of G3PP in two different radical prostatectomy (RP) cohorts with a total of 1797 patients, for whom information on biochemical recurrence (BCR), metastasis, and mortality was available. The association between biomarker expression, biochemical recurrence (BCR), bone metastasis, and prostate cancer-specific survival was established using log-rank and multivariable Cox regression analyses. High expression of G3PP in PC epithelial cells is associated with an increased risk of BCR, bone metastasis, and PC-specific mortality. Multivariate analysis revealed high G3PP expression in tumors as an independent predictor of BCR and bone metastasis development. High G3PP expression in tumors from patients eligible for prostatectomies is a new and independent prognostic biomarker of poor prognosis and aggressive PC for recurrence, bone metastasis, and mortality.

Population-based Assessment of Intermittent Androgen Deprivation Therapy Utilization for Relapsed, Nonmetastatic, Hormone-sensitive Adenocarcinoma of the Prostate

OBJECTIVES

Androgen deprivation therapy (ADT) is the standard of care for men with nonmetastatic hormone-sensitive prostate cancer (nmHSPC) after treatment failure. Although intermittent ADT (iADT) is noninferior to continuous ADT for prostate cancer outcomes, with superior quality of life and cost-to-benefit ratio, little is known regarding its real-world utilization. The authors aimed to determine the utilization of iADT in a Canadian Provincial Cancer Program for relapsed nmHSPC and identified risk factors associated with the nonreceipt of iADT.

MATERIALS AND METHODS

This retrospective population-based cohort study used linked administrative databases to identify all patients with relapsed nmHSPC from 2012 to 2016 and quantified ADT prescription history. Patients were defined as iADT eligible if prostate-specific antigen (PSA) was <4 ng/mL and trending downwards on ≥2 sequential PSAs after ≥6 months of ADT. Univariable and multivariable logistic regression analyses were performed to determine factors associated with nonreceipt of iADT.

RESULTS

A total of 601 men with relapsed, nmHSPC were included with a median age at relapse of 73 (range, 46 to 96), pre-ADT PSA of 12.2 ng/mL, and a median pre-ADT PSA doubling time of 7.8 months. 80.9% of the cohort were eligible to receive iADT and 74.4% were treated with iADT. On multivariable analysis, patients originally treated with surgery (odds ratio [OR], 0.19; 95% confidence interval [CI], 0.08-0.46) or having a Gleason Score ≥8 (OR, 0.30; 95% CI, 0.12-0.78) had decreased odds of receipt of iADT. Patients with longer PSA doubling times were more likely to receive iADT (OR, 2.71; 95% CI, 1.17-6.31).

CONCLUSIONS

The utilization of iADT was relatively common for men in Manitoba during the study period, however, the uptake of iADT can be improved among identified subgroups.

Role of salvage lymph node dissection in patients previously treated for prostate cancer: systematic review

Prostate cancer is the most common invasive cancer in men. Radical prostatectomy (RP) is a definitive treatment option, but biochemical recurrence can reach 40%. Salvage lymphadenectomy is a relatively recent approach to oligometasis and has been rapidly diffused primarily due to improvement in imaging diagnosis and results showing possibly promising therapy. A systematic literature review was performed in March 2020, according to the PRISMA statement. We excluded studies with patients with suspicion or confirmation of visceral and / or bone metastases. A total of 27 articles were included in the study. All studies evaluated were single arm, and there were no randomized studies in the literature. A total of 1,714 patients received salvage lymphadenectomy after previous treatment for localized prostate cancer. RP was the most used initial therapeutic approach, and relapses were based on PET / CT diagnosis, with Coline-11C being the most widely used radiopharmaceutical. Biochemical response rates ranged from 0% to 80%. The 5 years - Free Survival Biochemical recurrence was analyzed in 16 studies with rates of 0% up to 56.1%. The articles do not present high levels of evidence to draw strong conclusions. However, even if significant rates of biochemical recurrence are not evident in all studies, therapy directed to lymph node metastases may present good oncological results and postpone the onset of systemic therapy. The long-term impact in overall survival and quality of life, as well as the best strategies for case selection remains to be determined.

Patterns of Lymph Node Failure in Patients With Recurrent Prostate Cancer Postradical Prostatectomy and Implications for Salvage Therapies

PURPOSE

There is increasing use of radical prostatectomy to treat patients with high-risk prostate cancer. This has contributed toward a pathologic stage migration, and a greater number of patients are subsequently being diagnosed with biochemical failure. There is increasing use of advanced imaging techniques in the setting of biochemical failure, including positron emission tomography-computed tomography (PET-CT).

METHODS AND MATERIALS

This critical literature review highlights the evidence for PET-CT in postprostatectomy biochemical failure and identifies sites of pelvic lymph node relapse in the setting of biochemical failure and the potential implications that the locations of these relapses may have for salvage therapies. Potential future directions are then considered.

RESULTS

The optimal PET-CT tracer remains uncertain but there is increasing use of prostate-specific membrane antigen PET-CT for investigating sites of nodal metastasis at low prostate-specific antigen levels, and this is leading to a blurring of the biochemical and radiologic recurrence phases. The optimal therapeutic approach remains undefined, with current trials investigating postoperative radiation therapy to the whole pelvis in addition to the prostatic fossa, the use of PET-CT in the setting of biochemical recurrence to guide delivery of salvage radiation therapy, and, for patients with node-only relapsed prostate cancer, the addition of whole pelvis radiation therapy to metastasis-directed therapies such as stereotactic ablative radiotherapy.

CONCLUSIONS

The most appropriate target volume for salvage radiation therapy remains uncertain, and the findings of studies using PET-CT to map nodal recurrences suggest that there could be a role for extending whole pelvis radiation therapy volumes to increase coverage of superior nodal regions. The emerging fields of radiomics and radiogenomics could provide important prognostic information and aid decision making for patients with relapsed prostate cancer.

Metastasis-directed therapy and prostate-targeted therapy in oligometastatic prostate cancer: a systematic review

INTRODUCTION

The aim of this review was to summarize the available evidence on the role of metastasis-directed therapy (MDT) and/or prostate-targeted therapy (PTT) in the setting of oligometastatic prostate cancer (PCa).

EVIDENCE ACQUISITION

We searched PubMed, the Web of Science, and the Cochrane Library databases. The following keywords were used: ("prostate cancer" OR "prostate carcinoma" OR "prostate neoplasm" OR "prostate tumor") AND ("oligometastatic" OR "oligometastasis" OR "PSMA") AND ("surgery" OR "prostatectomy" OR "radical prostatectomy" OR "cytoreductive" OR "local treatment" OR "radiotherapy" OR "stereotactic" OR "stereotaxic") AND ("survival" OR "mortality").

EVIDENCE SYNTHESIS

After evaluating the selection criteria, 81 studies were evaluated for our endpoints. We included 22 studies for PTT of synchronous mPCa. There have been no randomized studies on cytoreductive prostatectomy (cRP). Four prospective studies showed that cRP was feasible but did not contribute to a positive effect on overall survival (OS). Regarding PTT-radiotherapy, two randomized controlled phase 3 trials showed that OS was improved in men with a low metastatic burden. Regarding MDT of metachronous lymph node recurrence, we included 29 retrospective studies. For MDT of oligometastases, we included 30 studies. One randomized phase 2 trial showed that androgen deprivation therapy-free survival improved with stereotactic body radiation therapy compared to that with surveillance; however, benefits on OS remain unclear.

CONCLUSIONS

We performed a comprehensive overview of the current literature on MDT and PTT. The feasibility of MDT and PTT is supported by several retrospective studies. Nevertheless, there remains a lack of high-quality trials to prove its survival benefits. Results from ongoing prospective trials data are awaited.

Site-specific relapse patterns of patients with biochemical recurrence following radical prostatectomy assessed by 68Ga-PSMA-11 PET/CT or 11C-Choline PET/CT: impact of postoperative treatments

BACKGROUND

Salvage radiotherapy (RT) (± androgen deprivation therapy (ADT)) is often used as a treatment in patients with biochemical recurrence (BCR) following radical prostatectomy (RP). Unfortunately, even after RT ± ADT, a significant number of patients will develop 'second' BCR. The aim of this study was to investigate the impact of postoperative treatments (adjuvant/salvage radiotherapy (RT) ± androgen deprivation therapy) on the recurrence pattern in patients with BCR following RP assessed by 11C-Choline PET/CT or 68 Ga-PSMA PET/CT.

METHODS

Patients who developed BCR following RP and who had at least one positive lesion on PET/CT were retrospectively assessed. Positive spots were mapped as local, lymph node (LN), skeletal or visceral recurrence. A distinction was made between locoregional (prostate bed and pelvic LN) and extrapelvic recurrence (skeletal, visceral and/or extrapelvic LN). Patients were categorized according to postoperative treatment received in three subgroups (RT, ADT and RT + ADT) and compared with the reference group (RP only). The impact of the radiation field was also investigated.

RESULTS

We identified 200 patients assessed by ⁶⁸Ga-PSMA-11 (80%) or ¹¹C-Choline PET/CT (20%). Patients who received postoperative RT + ADT had less LN recurrence distal to the common iliac bifurcation (26.7% vs 66.6%; p = 0.0004), but more recurrence to retroperitoneal LN than the reference group (38% vs. 14.4%, p = 0.02). Moreover, the RT + ADT subgroup had more extrapelvic recurrence compared to the reference group (66.2% vs 40.8%, p = 0.02). Patients who received RT to the prostate bed had more recurrence distal to the common iliac bifurcation compared to those who received RT to the prostate bed + pelvic LN (51.6% vs 26.1%, p = 0.0069).

CONCLUSION

Post-prostatectomy treatments (ADT and/or RT) and the postoperative radiation field (prostate bed vs. prostate bed + pelvis) have a significant impact on the recurrence pattern. This knowledge can help clinicians to counsel their patients on their chances of being eligible for (locoregional) metastasis-directed therapies.

Metastasis-directed therapy for oligometastatic urological tumours: still no second-hand news

For patients presenting with limited metastatic disease burden, known as the oligometastatic state of disease, a more aggressive treatment approach targeting the new or progressive metastatic lesions might improve patient outcome, with no or only limited toxicity to be expected from the treatment. This review provides an overview of the existing evidence and on-going trials on oligometastatic disease and metastasis-directed therapy in the field of renal, bladder and prostate cancer.

PSA Doubling Time and Absolute PSA Predict Metastasis-free Survival in Men With Biochemically Recurrent Prostate Cancer After Radical Prostatectomy

INTRODUCTION

The aim of this study was to investigate the association of prostate-specific antigen (PSA) values on metastasis-free survival (MFS) in men with biochemically recurrent prostate cancer (BRPC) and PSA doubling time (PSADT) < 12 months. This dataset also reflects an update with longer follow-up of our prior publications on the natural history of BRPC in the absence of treatment.

MATERIALS AND METHODS

In this report, we combined databases from the Center for Prostate Disease Research and Johns Hopkins University (CPDR/JHU). In the CPDR/JHU radical prostatectomy database (30,936 total patients), 656 men with BRPC (> 0.2 ng/mL) after prostatectomy and PSADT < 12 months, who received no adjuvant/salvage androgen deprivation and/or radiation therapy, were prospectively followed until radiologic evidence of metastasis and are included in this analysis.

RESULTS

Metastasis occurred in 250 of 656 patients with BRPC (median follow-up, 5 years). PSADT < 7.5 months and Gleason score were independent risk factors for distant metastasis in multivariable analysis. Risk of metastasis increased for PSADT 6.01 to 7.50, 4.51 to 6.0, 3.01 to 4.50, and ≤ 3.0 months, after adjusting for Gleason score. A PSA value ≥ 0.5 ng/mL significantly and independently increased risk of metastasis in patients with PSADT < 12 months (hazard ratio, 2.79; 95% confidence interval, 1.47-5.29; P = .001).

CONCLUSIONS

In men with PSADT < 12 months, PSADT ≤ 7.5 months, PSA ≥ 0.5 ng/mL, and Gleason score are independent predictors of MFS on multivariable analysis.

Relationship Between Metastasis-free Survival and Overall Survival in Patients With Nonmetastatic Castration-resistant Prostate Cancer

BACKGROUND

Metastasis-free survival (MFS) has been shown to be predictive of overall survival (OS) in hormone-sensitive localized prostate cancer. We evaluated the relationship between MFS and OS in nonmetastatic castration-resistant prostate cancer (nmCRPC).

PATIENTS AND METHODS

A retrospective analysis of 1207 high-risk patients with nmCRPC from the SPARTAN study (clinicaltrials.gov, NCT01946204) was undertaken. Landmark analyses of MFS status at several time points from randomization were performed to minimize guarantee-time bias. Hazard ratio (HR) of death as a function of MFS status was estimated based on a Cox proportional hazards model with 2-sided 95% confidence interval (CI). Estimated HRs were adjusted for stratification factors. Correlation analysis was performed using the Fleischer method.

RESULTS

At all time points, MFS status strongly predicted OS. At landmark time points of 6, 9, and 12 months, risk of death was significantly higher for patients with metastases versus those without (adjusted HR at 6 months = 4.12; 95% CI, 2.60-6.54; P < .0001). MFS was positively correlated with OS based on the Fleischer method (HR, 0.69; 95% CI, 0.69-0.70; P < .0001). Approximately one-half of the variability in OS can be explained by MFS.

CONCLUSION

Metastasis development, regardless of time point, is associated with significantly greater risk of death in men with high-risk nmCRPC; hence, MFS is predictive of OS.

Stereotactic body radiotherapy for bone oligometastatic disease in prostate cancer

Purpose

There are sparse data describing outcomes of bone-only oligometastatic prostate cancer in comparison with lymph node disease treated with stereotactic body radiotherapy (SBRT). The primary aim of this study was to report progression-free survival (PFS) data for patients with bone-only disease. Influence of hormone sensitivity and androgen deprivation therapy use was also assessed.

Methods

This is a single-centre retrospective cohort study. Hormone-sensitive and castrate-resistant patients with oligometastatic (≤ 3) bone-only prostate cancer treated with SBRT were included. Data were collected using electronic records. Kaplan–Meier survivor function, log rank test, as well as Cox regression were used to calculate PFS and overall survival.

Results

In total, 51 patients with 64 bone metastases treated with SBRT were included. Nine patients were castrate resistant and 42 patient’s hormone sensitive at the time of SBRT. Median follow-up was 23 months. Median PFS was 24 months in hormone-sensitive patients and 3 months in castrate-resistant patients. No patients experienced grade 3 or 4 toxicities. There were three in-field recurrences.

Conclusions

In this study, patients with bone oligometastatic disease showed potential benefit from SBRT with a median PFS of 11 months. Hormone-sensitive patients showed the greatest benefit, with results similar to that published for oligometastatic pelvic nodal disease treated with SBRT. Prospective randomised control trials are needed to determine the survival benefit of SBRT in oligometastatic bone-only prostate cancer and to determine prognostic indicators.

Electronic supplementary material

The online version of this article (10.1007/s00345-019-02873-w) contains supplementary material, which is available to authorized users.

Outcomes after a first and/or second salvage treatment in patients with oligometastatic prostate cancer recurrence detected by (18-F) choline PET-CT

OBJECTIVE

The primary objective of this study was to assess clinical outcomes in patients with oligometastatic prostate cancer recurrence after single or repeated salvage radiation treatment.

METHODS

Forty-nine consecutive prostate cancer patients diagnosed with oligometastatic recurrence on Ch-PET have been prospectively treated. Seven (23%) patients had castrate-resistant disease. Clinical outcomes were assessed using the Kaplan-Meier method. Potential prognostic factors were examined using univariate proportional hazards regression.

RESULTS

The treatments administered to the initial oligorecurrence sites were intensity-modulated radiotherapy (IMRT) ± ADT (26 patients; 53%) and stereotactic ablative radiotherapy (SABR) ± ADT (23 patients; 47%). With a median follow-up of 24 months (range 6-39), 24 patients developed a biochemical failure. Twenty out of the 24 relapsed patients underwent a second Ch-PET/CT. Seven patients presented poly-metastatic relapse and 10 oligometastatic diseases. Six of 10 patients with a second oligorecurrence were treated again with SABR. Overall, 102 lesions were treated. Local control was detected in 45 (91.8%) patients. No relevant (grade ≥ 2) toxicity was reported, and there was no grade 3 toxicity. On univariate analysis, none of the variables were significantly predicted for clinical disease-free survival. At last follow-up visit, 24 patients (40%) were free from biochemical failure and 37 (71%) patients were free from clinical disease. The 2-year OS and PCSS were 91.8% and 95.9% respectively.

CONCLUSION

Salvage IMRT or SBRT of oligometastatic prostate cancer recurrence is associated with a prolonged cDFS. This may result in a longer time to develop castrate-resistant disease and a longer time without systemic therapies.

The Current Landscape of Treatment in Non-Metastatic Castration-Resistant Prostate Cancer

Non-metastatic castration-resistant prostate cancer (nmCRPC) is a heterogeneous disease with variable potential in developing into overt metastases. It is an area of increased unmet need in advanced prostate cancer and for which there had been no great treatments until recent US Food and Drug Administration (FDA) approval of 2 novel anti-androgens apalutamide and enzalutamide, which were both approved given benefit in metastasis-free survival. Early data on the use of darolutamide, another novel anti-androgen, are also explored. This review discusses the pivotal trials that led to the approval of apalutamide and enzalutamide in the nmCRPC setting and discusses the key promises and challenges with the use of these agents.

68Ga-PSMA PET/CT-based metastasis-directed radiotherapy for oligometastatic prostate cancer recurrence after radical prostatectomy

PURPOSE

The aim of this communication was to assess the efficacy of directed oligometastatic radiotherapy (RT) based on ⁶⁸Ga-PSMA PET/CT in patients with prostate cancer (PCa) biochemical relapse (BCR) after primary treatment with curative intent.

METHODS

This is a retrospective analysis of a monocentric cohort of PCa patients diagnosed with oligometastatic disease on ⁶⁸Ga-PSMA PET/CT and treated with metastasis-directed RT. Inclusion criteria were: histologically proven PCa, BCR after primary treatment with curative intent, oligometastatic disease defined as ≤ 3 metastatic lesions. To evaluate the efficacy of the therapy, biochemical response defined as a decrease of > 50% of PSA (PSA₅₀) was measured at 1 and 4 months. Patients were followed up until progression and start of androgen deprivation therapy (ADT). BCR-free survival and ADT-free survival were calculated.

RESULTS

20 patients met the inclusion criteria. Median PSA value: 1.4 ng/ml (IQR, 0.3-2.3 ng/ml). A total of 30 PSMA-positive lesions were treated: 18 lymph nodes (60%), nine bone (30%) and three visceral lesions (10%). Median follow-up was 15 months (range 4-33 months). Biochemical response at 1 and 4 months was found in 3/20 patients (15%) and 14/20 (70%), respectively. BCR-free survival rate at 1 year was 79% and 53% at 2 years. ADT-free survival at 2 years was 74%.

CONCLUSION

This retrospective study suggests that metastasis-directed RT based on ⁶⁸Ga-PSMA PET/CT may be a valuable treatment in patients with PCa oligometastatic disease, providing promising BCR-free survival rates and potentially postponing ADT for at least 2 years in 74% of the patients. Response assessment should not be measured before 4 months after treatment.

Single-fraction Stereotactic Body Radiation Therapy versus Conventionally Fractionated Radiation Therapy for the Treatment of Prostate Cancer Bone Metastases

Purpose

This study aimed to compare outcomes of patients with prostate cancer with bone metastases treated with stereotactic body radiation therapy (SBRT) versus conventionally fractionated radiation therapy (CFRT).

Methods and materials

An institutional, retrospective review was conducted of patients with prostate cancer receiving radiation therapy to bone metastases. In-field failure (IFF) was the primary outcome of the study, and distant failure (DF) and biochemical failure (BF) were secondary outcomes.

Results

A total of 249 metastases (191 SBRT; 58 CFRT) in 201 patients with a median follow-up of 2.2 years were analyzed. The SBRT prescription dose was predominantly 18 Gy (45.5%) or 20 Gy (46.6%) in a single fraction. CFRT was given either as 8 Gy in 1 fraction (56.9%) or 20 Gy in 5 fractions (41.4%). Imaging follow up was performed most frequently with ¹¹C-choline positron emission tomography/computed tomography (79%) or bone scan (10%). The median time to IFF was 1.6 years for CFRT-treated lesions and not met (>4.4 years) for SBRT. The 1- and 3-year IFF estimates were 34.4% (95% confidence interval [CI], 19.9-46.2) and 53.3% (95% CI, 34.3-66.8) for lesions treated with CFRT compared with 4.5% (95% CI, 1.4-7.5) and 12.9% (95% CI, 6.6-18-8) for those treated with SBRT (P < .01). On multivariate regression, the hazard ratio (HR) for IFF with CFRT compared with SBRT was 6.8 (95% CI, 3.7-12.5; P < .01). There were nonsignificant reduced rates of BF (HR, 1.4; 95% CI, 1.0-2.1; P = .05) and DF (HR, 1.3; 95% CI, 1.0-1.8; P = .08) in patients who received SBRT. The 3-year BF and DF estimates in these patients were 88.6% (95% CI, 82.0-92.8) and 82.2% (95% CI, 74.5-87.6), respectively.

Conclusions

SBRT for the management of prostate cancer bone metastases significantly reduces radiographic IFF. However, the high rate of subsequent DF and BF highlights the challenges in selecting patients who may benefit from aggressive radiation therapy.

Discovery and validation of a serum microRNA signature to characterize oligo- and polymetastatic prostate cancer: not ready for prime time

PURPOSE

Patients with oligometastatic prostate cancer (PC) may benefit from metastasis-directed therapy (MDT), delaying disease progression and the start of palliative systemic treatment. However, a significant proportion of oligometastatic PC patients progress to polymetastatic PC within a year following MDT, suggesting an underestimation of the metastatic load by current staging modalities. Molecular markers could help to identify true oligometastatic patients eligible for MDT.

METHODS

Patients with asymptomatic biochemical recurrence following primary PC treatment were classified as oligo- or polymetastatic based on 18^F-choline PET/CT imaging. Oligometastatic patients had up to three metastases at baseline and did not progress to more than three lesions following MDT or surveillance within 1 year of diagnosis of metastases. Polymetastatic patients had > 3 metastases at baseline or developed > 3 metastases within 1 year following imaging. A model aiming to prospectively distinguish oligo- and polymetastatic PC patients was trained using clinicopathological parameters and serum-derived microRNA expression profiles from a discovery cohort of 20 oligometastatic and 20 polymetastatic PC patients. To confirm the models predictive performance, it was applied on biomarker data obtained from an independent validation cohort of 44 patients with oligometastatic and 39 patients with polymetastatic disease.

RESULTS

Oligometastatic PC patients had a more favorable prognosis compared to polymetastatic ones, as defined by a significantly longer median CRPC-free survival (not reached versus 38 months; 95% confidence interval 31-45 months with P < 0.001). Despite the good performance of a predictive model trained on the discovery cohort, with an AUC of 0.833 (0.693-0.973; 95% CI) and a sensitivity of 0.894 (0.714-1.000; 95% CI) for oligometastatic disease, none of the miRNA targets were found to be differentially expressed between oligo- and polymetastatic PC patients in the signature validation cohort. The multivariate model had an AUC of 0.393 (0.534 after cross-validation) and therefore, no predictive ability.

CONCLUSIONS

Although PC patients with oligometastatic disease had a more favorable prognosis, no serum-derived biomarkers allowing for prospective discrimination of oligo- and polymetastatic prostate cancer patients could be identified.

Oligometastatic prostate cancer: Reality or figment of imagination?

The term “oligometastatic prostate cancer” refers to a heterogeneous group of disease states currently defined solely on the basis of clinical features. Oligorecurrent disease, de novo oligometastases, and oligoprogressive disease likely have unique biologic underpinnings and natural histories. Evidence suggesting the existence of a subset of patients who harbor prostate cancer with limited metastatic potential currently includes disparate and overwhelmingly retrospective reports. Nevertheless, emerging prospective data have corroborated the “better‐than‐expected,” retrospectively observed outcomes, particularly in the setting of oligorecurrent prostate cancer. Improved functional imaging with prostate‐specific membrane antigen‐targeted strategies may enhance the identification of patients with oligometastatic prostate cancer in the short term. In the long term, refinement of the oligometastatic case definition likely will require biologic risk‐stratification schemes. To determine optimal treatment strategies and identify patients most likely to benefit from metastasis‐directed therapy, future efforts should focus on conducting high‐quality, prospective trials with much‐needed molecular correlative studies.

The term “oligometastatic prostate cancer” currently refers to a heterogeneous group of clinically defined disease states. To improve patient risk stratification and determine optimal treatment strategies, future efforts should focus on conducting prospective trials and determining a biologic categorization of patients with limited metastatic potential.

Enzalutamide: a new indication for nonmetastatic castration-resistant prostate cancer

PROSPER is an international Phase III trial demonstrating the beneficial role of enzalutamide, an androgen receptor antagonist, in prolonging metastasis-free survival in men with nonmetastatic castration-resistant prostate cancer. The trial showed that the median metastasis-free survival was 21.9 months longer for those treated with enzalutamide (36.6 months) compared to those treated with placebo (14.7 months). Enzalutamide also showed prolonged time to PSA progression, PSA response, and time to initiating additional antineoplastic therapy although overall survival is not yet reached. Enzalutamide is the second antiandrogen (next to apalutamide) that has gained the United States Food and Drug Administration (US FDA) label indication for use in the setting of nonmetastatic castration-resistant prostate cancer.

Novel Insights into the Management of Oligometastatic Prostate Cancer: A Comprehensive Review

CONTEXT

The current standard of care for metastatic prostate cancer (PCa) is androgen deprivation therapy (ADT) plus either docetaxel or abiraterone. Growing evidence suggests that metastasis-directed therapy (MDT) and/or local therapy targeted to the primary tumour (ie, prostate) may be of benefit in the setting of oligometastatic disease. Several prospective studies are underway; however, until robust evidence is available to guide treatment decisions, physicians are challenged with how best to manage patients with oligometastases.

OBJECTIVE

This comprehensive review aims to collate the available evidence to date for a role of MDT and/or prostate-targeted therapy in the setting of oligometastatic PCa, as well as discuss ongoing trials in this setting.

EVIDENCE ACQUISITION

We searched PubMed for the combination of "prostate cancer" and "oligometastatic", "oligometastases", "oligometastasis", "solitary metastases", "stereotactic body radiotherapy", "SBRT", "stereotactic ablative radiotherapy", "SABR", "salvage lymphadenectomy", or "metastasectomy" in publications over the last 20yr. We also searched ClinicalTrials.gov to identify relevant ongoing trials.

EVIDENCE SYNTHESIS

The studies were divided according to the timing of metastasis into synchronous (ie, detected at the time of primary PCa diagnosis) and metachronous (ie, detected after treatment of the primary tumour), and according to treatment modality into MDT (including salvage lymph node dissection [sLND]) and prostate-targeted treatment. For MDT of synchronous/metachronous metastases, we included 16 completed studies and 11 ongoing prospective studies. In the case of sLND for nodal-only recurrence after primary treatment with curative intent, we included 11 completed studies. Finally, for prostate-targeted treatment of synchronous metastatic PCa, we included 25 completed studies and 11 ongoing prospective studies. In selected patients with oligorecurrent disease, early detection and aggressive treatment of metastatic lesions (surgery or radiotherapy) appears to be a feasible strategy and may delay the use of systemic therapies. MDT is a promising option in oligometastatic PCa patients, but more robust data are needed. In the setting of synchronous oligometastatic disease, aggressive cytoreductive treatment needs further data to confirm the benefits.

CONCLUSIONS

In this review, we provide a comprehensive overview of the current literature on the treatment of patients with oligometastatic PCa. The data suggest that although ADT plus either docetaxel or abiraterone remains the mainstay of treatment for mPCa, in oligometastatic PCa, improved outcomes may be achieved with metastasis- and prostate-targeted therapies. The studies included in this review are mainly retrospective in nature, limiting the strength of the evidence they provide. Prospective studies are ongoing, and their results are eagerly awaited.

PATIENT SUMMARY

We reviewed the treatment of patients with prostate cancer that has spread to five sites or fewer. We conclude that while androgen deprivation plus either docetaxel or abiraterone should remain the standard of care, there is evidence that treatment targeted at the metastases and the primary tumour may improve the outcome for the patient and potentially delay the use of systemic treatment.

Consensus on management of castration-resistant prostate cancer on behalf of the Urological Tumours Working Group (URONCOR) of the Spanish Society of Radiation Oncology

BACKGROUND

The knowledge in the field of castration-resistant prostate cancer (CRPC) is developing rapidly, with emerging new therapies and advances in imaging. Nonetheless, in multiple areas there is still a lack of or very limited evidence, and clear guidance from clinicians regarding optimal strategy is required.

METHODS

A modified Delphi method, with 116 relevant questions divided into 7 different CRPC management topics, was used to develop a consensus statement by the URONCOR group.

RESULTS

A strong consensus or unanimity was reached on 93% of the proposed questions. The seven topics addressed were: CRPC definition, symptomatic patients, diagnosis of metastasis, CRPC progression, M0 management, M1 management and sequencing therapy, and treatment monitoring.

CONCLUSIONS

The recommendations based on the radiation oncology experts' opinions are intended to provide cancer specialists with expert guidance and to standardise CRPC patient management in Spain, facilitating decision-making in different clinically relevant issues regarding CRPC patients.

Worth a local treatment? - Analysis of modern radiotherapy concepts for oligometastatic prostate cancer

Background

Prostate cancer (PCA) is the most-prevalent non-skin cancer in men worldwide. Nevertheless, the treatment of oligometastatic, especially lymph-node (ln) recurrent, PCA remains elusive. The aim of our study was to provide insights in radiotherapy (RT)-treatment of recurrent PCA exhibiting ln- or osseous (oss)-oligometastases.

Methods

Between April 2012 and April 2017, 27 oligometastatic PCA patients (19 ln and 8 single oss) were treated with RT at our institution.

Results

The metastasis-free survival (MFS) was 24.8 m (22.0–36.0 m) and 25.4 m (23.9–28.1 m) for the ln- and oss-subgroup resulting in 1-year MFS of 75.4 and 100% and 2-year MFS of 58.7 and 83.3% for ln- and oss-metastatic patients, respectively. Of notice, none of the recurrences for ln-patients was in the RT-field, constituting a local control of 100%.

Within the ln-group, pre-RT median-PSA was 2.6 ng/ml, median post-RT PSA was 0.3 ng/ml, which was significant (p = 0.003). Median biochemical-free survival (bfS) was 12.2 m. PCA that was initially confined to the prostate had a better bfS (p < 0.001) and MFS (p = 0.013). The oss-group had a median PSA of 4.9 ng/ml pre-treatment which dropped to a median value of 0.14 ng/ml (p = 0.004).

Toxicities were moderate, with only 1 case of III° toxicity. There were no deaths in the ln-group, thus overall survial was 100% here.

Conclusion

Our study points out the feasibility of RT as a treatment option in recurrent PCA and demonstrates an excellent local control with a low-toxicity profile.

Stereotactic ablative radiation therapy for oligometastatic prostate cancer delays time-to-next systemic treatment

PURPOSE

Local ablative treatment to oligometastatic patients can result in long-term disease-free survival in some cancer patients. The importance of this treatment paradigm in prostate cancer is a rapidly evolving field. Herein, we report on the safety and preliminary clinical outcomes of a modern cohort of oligometastatic prostate cancer (OPC) patients treated with consolidative stereotactic ablative radiation (SABR).

METHODS

Records of men with OPC who underwent consolidative SABR at our institution were reviewed. SABR was delivered in 1-5 fractions of 5-18 Gray. Kaplan-Meier estimates of local progression-free survival (LPFS), biochemical progression-free survival (bPFS; PSA nadir + 2), distant progression-free survival (DPFS), and time-to-next intervention (TTNI) were calculated.

RESULTS

In total, 66 OPC patients were identified with consolidative SABR delivered to 134 metastases: 89 bone, 40 nodal, and 5 viscera. The majority of men (49/66) had hormone-sensitive prostate cancer (HSPC). Crude grade 1 and 2 acute toxicities were 36% and 11%, respectively, with no ≥ grade 3 toxicity. At 1 year, LPFS was 92% and bPFS and DPFS were 69%. Of the 18 men with HSPC who had deferred hormone therapy , 11 (56%) remain disease free following SABR (1-year ADT-FS was 78%). In 17 castration-resistant men, 11 had > 50% prostate-specific antigen (PSA) declines with 1-year TTNI of 30%.

CONCLUSIONS

Consolidative SABR in OPC is feasible and well tolerated. The heterogeneity and small size of our series limit extrapolation of clinically meaningful outcomes following consolidative SABR in OPC, but our preliminary data suggest that this approach warrants continued prospective study.

The efficacy of Stereotactic body radiation therapy and the impact of systemic treatments in oligometastatic patients from prostate cancer

BACKGROUND

Diagnoses of oligometastatic prostate cancer (PC) increased in the recent years thanks to the advancement in imaging and more effective systemic therapies. Here we evaluate the efficacy of Stereotactic Body Radiation Therapy (SBRT) in oligorecurrent and oligoprogressive PC.

METHODS

We included patients with a maximum of five metastases diagnosed in a maximum of two target organs. Concomitant treatment with hormonal therapies or chemotherapies was allowed. End points of the present study were the outcome in terms of Local control of treated metastases (LC), out-field progression free survival, overall progression free survival (PFS), and overall survival.

RESULTS

We included in the analysis 64 patients treated on 90 metastases. Fifty (78.1%) patients were treated on lymph nodes, 2 (3.1%) patients simultaneously on lymph node and bone while 10 (15.7%) patients on bone only. Lung metastases were treated in 2 (3.1%) patients. Thirty-seven (57.81%) were without androgen deprivation therapy when treated with SBRT. Median follow-up was 15.2 months. Rates of LC at 6-, 12-, and 18- months were 94%, 88%, and 84%, respectively. Oligoprogressive patients compared to oligorecurrent (HR 9.10, P = 0.049) and prolongation of time from diagnosis of metastases to SBRT (HR 1.03, P = 0.047) were associated with worse LC. Median PFS was 6.6 months (range 1.1-42.4). Castration resistant patients experienced worse PFS compared to castration sensitive group (HR 2.12, P = 0.021).

CONCLUSIONS

Stereotactic body radiation therapy seems to be an effective treatment for metastases from PC. Prospective trials are necessary to better define selection of patients and to evaluate combination of SBRT and new systemic drugs in castration resistant patients.

Prospective comparison of 68Ga-PSMA PET/CT, 18F-sodium fluoride PET/CT and diffusion weighted-MRI at for the detection of bone metastases in biochemically recurrent prostate cancer

PURPOSE

To prospectively compare diagnostic accuracies for detection of bone metastases by ⁶⁸Ga-PSMA PET/CT, ¹⁸F-NaF PET/CT and diffusion-weighted MRI (DW₆₀₀-MRI) in prostate cancer (PCa) patients with biochemical recurrence (BCR).

METHODS

Sixty-eight PCa patients with BCR participated in this prospective study. The patients underwent ⁶⁸Ga-PSMA PET/CT, a ¹⁸F-NaF PET/CT and a DW₆₀₀-MRI (performed in accordance with European Society of Urogenital Radiology guidelines, with b values of 0 and 600 s/mm²). Bone lesions were categorized using a three-point scale (benign, malignant or equivocal for metastases) and a dichotomous scale (benign or metastatic) for each imaging modality by at least two experienced observers. A best valuable comparator was defined for each patient based on study-specific imaging, at least 12 months of clinical follow-up and any imaging prior to the study and during follow-up. Diagnostic performance was assessed using a sensitivity analysis where equivocal lesions were handled as non-metastatic and then as metastatic.

RESULTS

Ten of the 68 patients were diagnosed with bone metastases. On a patient level, sensitivity, specificity and the area under the curve (AUC) by receiver operating characteristic analysis were, respectively, 0.80, 0.98-1.00 and 0.89-0.90 for ⁶⁸Ga-PSMA PET/CT (n = 68 patients); 0.90, 0.90-0.98 and 0.90-0.94 for ¹⁸NaF PET/CT (n = 67 patients); and 0.25-0.38, 0.87-0.92 and 0.59-0.62 for DW₆₀₀-MRI (n = 60 patients). The diagnostic performance of DW₆₀₀-MRI was significantly lower than that of ⁶⁸Ga-PSMA PET/CT and ¹⁸NaF PET/CT for diagnosing bone metastases (p < 0.01), and no significant difference in the AUC was seen between ⁶⁸Ga-PSMA PET/CT and ¹⁸NaF PET/CT (p = 0.65).

CONCLUSION

⁶⁸Ga-PSMA PET/CT and ¹⁸F-NaF PET/CT showed comparable and high diagnostic accuracies for detecting bone metastases in PCa patients with BCR. Both methods performed significantly better than DW₆₀₀-MRI, which was inadequate for diagnosing bone metastases when conducted in accordance with European Society of Urogenital Radiology guidelines.

Standard of Care Versus Metastases-directed Therapy for PET-detected Nodal Oligorecurrent Prostate Cancer Following Multimodality Treatment: A Multi-institutional Case-control Study

BACKGROUND

Most prostate cancer (PCa) patients with a biochemical failure following primary multimodality treatment (surgery and postoperative radiotherapy) relapse in the nodes.

OBJECTIVE

To perform a matched-case analysis in men with lymph node recurrent PCa comparing standard of care (SOC) with metastasis-directed therapy (MDT).

DESIGN, SETTING, AND PARTICIPANTS

PCa patients with a prostate-specific antigen (PSA) progression following multimodality treatment were included in this retrospective multi-institutional analysis.

INTERVENTION

The SOC cohort (n=1816) received immediate or delayed androgen deprivation therapy administered at PSA progression. The MDT cohort (n=263) received either salvage lymph node dissection (n=166) or stereotactic body radiotherapy (n=97) at PSA progression to a positron emission tomography-detected nodal recurrence.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

The primary endpoint, cancer-specific survival (CSS), was analyzed using the Kaplan-Meier method, log-rank test, Cox proportional hazards models, and propensity score-matched analyses.

RESULTS AND LIMITATIONS

At a median follow-up of 70 (interquartile range: 48-98) mo, MDT was associated with an improved CSS on univariate (p=0.029) and multivariate analysis (hazard ratio: 0.33, 95% confidence interval [CI]: 0.17-0.64) adjusted for the year of radical prostatectomy (RP), age at RP, PSA at RP, time from RP to PSA progression, Gleason score, surgical margin status, pT- and pN-stage. In total, 659 men were matched (3:1 ratio). The 5-yr CSS was 98.6% (95% CI: 94.3-99.6) and 95.7% (95% CI: 93.2-97.3) for MDT and SOC, respectively (p=0.005, log-rank). The main limitations of our study are its retrospective design and lack of standardization of systemic treatment in the SOC cohort.

CONCLUSIONS

MDT for nodal oligorecurrent PCa improves CSS as compared with SOC. These retrospective data from a multi-institutional pooled analysis should be considered as hypothesis-generating and inform future randomized trials in this setting.

PATIENT SUMMARY

Prostate cancer patients experiencing a lymph node recurrence might benefit from local treatments directed at these lymph nodes.

Prognostic Value of [18F]-Fluoromethylcholine Positron Emission Tomography/Computed Tomography Before Stereotactic Body Radiation Therapy for Oligometastatic Prostate Cancer

PURPOSE

To investigate the predictive value of [¹⁸F]-fluoromethylcholine positron emission tomography/computed tomography (PET/CT)-derived parameters on progression-free survival (PFS) in oligometastatic prostate cancer patients treated with stereotactic body radiation therapy (SBRT).

METHODS AND MATERIALS

In [¹⁸F]-fluoromethylcholine PET/CT scans of 40 consecutive patients with ≤4 metachronous metastases treated with SBRT we retrospectively measured the number of metastases, standardized uptake values (SUV_mean, SUV_max, SUV_peak), metabolically active tumor volume (MATV), and total lesion choline uptake. Partial-volume correction was applied using the iterative deconvolution Lucy-Richardson algorithm.

RESULTS

Thirty-seven lymph node and 13 bone metastases were treated with SBRT. Thirty-three patients (82.5%) had 1 lesion, 4 (10%) had 2 lesions, and 3 (7.5%) had 3 lesions. After a median follow-up of 32.6 months (interquartile range, 35.5 months), the median PFS was 11.5 months (95% confidence interval 8.4-14.6 months). Having more than a single metastasis was a significant prognostic factor (hazard ratio 2.74; P = .03), and there was a trend in risk of progression for large MATV (hazard ratio 1.86; P = .10). No SUV or total lesion choline uptake was significantly predictive for PFS, regardless of partial-volume correction. All PET semiquantitative parameters were significantly correlated with each other (P ≤ .013).

CONCLUSIONS

The number of choline-avid metastases was a significant prognostic factor for progression after [¹⁸F]-fluormethylcholine PET/CT-guided SBRT for recurrent oligometastatic prostate cancer, and there seemed to be a trend in risk of progression for patients with large MATVs. The lesional level of [¹⁸F]-fluoromethylcholine uptake was not prognostic for progression.

Oligometastatic recurrent prostate cancer detects by fluorine-18-choline positron emission tomography/computed tomography in patients with prostate-specific antigen levels of up to 5 ng/ml

PURPOSE

The aim of this study was to assess the ability of fluorine-18-fluorocholine (F-FCH) PET/computed tomography (CT) to detect oligometastatic disease (OMD) in patients with early recurrence of prostate cancer (PC) [prostate-specific antigen (PSA)≤5 ng/ml].

PATIENTS AND METHODS

Between 2010 and 2016, 324 patients with PC and PSA levels of less than or equal to 5 ng/ml were recruited. The mean (SD) age of the patients was 71 (10) years. All patients were treated with a radical prostatectomy±lymphadenectomy. One-hundred and twenty-one patients were under hormonal therapy at the time of PET/CT, whereas 203 were not. The mean (SD) PSA at the time of PET/CT was 1.33 (1.19) ng/ml, the mean (SD) PSA doubling time (PSAdt) was 10 (12) months, and the mean (SD) PSA velocity (PSAvel) was 1.94 (3.31) ng/ml/year. The correlation between continuous and categorical data was assessed using Student's t-test or by analysis of variance and by the χ-test, respectively. Univariate and multivariate analysis was carried out for the identification of clinical variables able to predict the presence of OMD.

RESULTS

One-hundred and ninety-three patients had a negative F-FCH PET/CT, whereas 131 (40.4%) had a positive scan. Of these latter patients, 35 had a significant F-FCH uptake in the prostatic fossae, 59 in the lymph nodes, and 37 in bone. PSA levels were significantly different between patients with a positive than those with a negative scan (P<0.001). F-FCH PET/CT was negative in the majority of patients with a PSA of less than or equal to 1 (63.2%) ng/ml. More than 60% of patients with a PSAdt of less than or equal to 6 months had a positive F-FCH PET/CT scan for OMD. PSAvel was higher in patients with a positive scan than those with a negative finding. At univariate analysis, PSA level, PSAdt, and PSAvel were predictors of a positive F-FCH PET/CT for OMD, whereas on multivariate analysis, only PSA level and PSAdt were independent predictors (both P<0.01). Furthermore, PSAdt was the only independent predictor of OMD at the lymph node level.

CONCLUSION

In patients with early recurrence of PC, F-FCH PET/CT is able to detect OMD in 40% of cases. This finding has an important impact on the detection of PC recurrent lesions that could be treated by local therapy to achieve long-term survival or cure.

Case: Testicular oligometastasis from prostate cancer - Report of rare isolated recurrence after radiotherapy and intermittent androgen-deprivation therapy

Testicular oligometastasis secondary to prostate cancer is rare. We present a case where a patient with locally advanced prostate cancer was treated with high-dose external beam radiotherapy and two years of androgen-deprivation therapy, followed by intermittent androgen suppression. Three and a half years after initial diagnosis, he was found to have a painless testicular mass. Orchiectomy was performed and histopathology demonstrated metastatic prostatic adenocarcinoma. He remains in clinical remission on intermittent androgen suppression eight years following initial treatment, and over four years after presentation with testicular metastasis.

Radiation therapy for oligorecurrence in prostate cancer. Preliminary results of our centre

INTRODUCTION AND OBJECTIVE

There is growing interest in the use of more aggressive therapeutic modalities for treating metastatic prostate cancer. In this study, we examine the use of stereotactic body radiation therapy (SBRT) for patients with oligorecurrent prostate cancer. We analysed the biochemical response and toxicity of patients who underwent this therapy at our centre.

MATERIAL AND METHOD

We selected patients who experienced oligorecurrence between January 2015 to December 2016 and were administered SBRT. The association of androgen deprivation (AD) was left in each case to the decision of the tumour committee. We describe the clinical situation at diagnosis of oligorecurrence, the treatment administered and the biochemical response. We considered a biochemical response to be a 50% reduction in the absolute prostate-specific antigen (PSA) readings.

RESULTS

SBRT was administered to 11 patients with bone (82%) and/or lymph node oligometastasis (18%). The treatment regimen for bone oligometastasis was 27Gy divided into 3 sessions, while the treatment for lymph node oligometastasis reached 70Gy. Seven patients had no treatment at the time of diagnosis, 2 were in the castration-resistant phase, 1 patient was in the off phase of intermittent AD, and 1 patient had adjuvant AD for pN1. Seven patients presented a biochemical response with a PSA reduction of 75-100%. The response was not assessable in 4 patients due to the continuing adjuvant AD. With a mean follow-up of 10.5 months, only 2 patients had progressed. Grade 1 gastrointestinal toxicity was detected in only 1 patient.

CONCLUSION

Our data suggest that the use of SBRT in carefully selected patients with metastatic oligorecurrence of prostate cancer can achieve biochemical response and potentially delay progression and the use of systemic treatments.

Prostate Cancer Molecular Imaging Standardized Evaluation (PROMISE): Proposed miTNM Classification for the Interpretation of PSMA-Ligand PET/CT

Prostate-specific membrane antigen (PSMA)-ligand PET imaging provides unprecedented accuracy for whole-body staging of prostate cancer. As PSMA-ligand PET/CT is increasingly adopted in clinical trials and routine practice worldwide, a unified language for image reporting is urgently needed. We propose a molecular imaging TNM system (miTNM, version 1.0) as a standardized reporting framework for PSMA-ligand PET/CT or PET/MRI. miTNM is designed to organize findings in comprehensible categories to promote the exchange of information among physicians and institutions. Additionally, flowcharts integrating findings of PSMA-ligand PET and morphologic imaging have been designed to guide image interpretation. Specific applications, such as assessment of prognosis or impact on management, should be evaluated in future trials. miTNM is a living framework that evolves with clinical experience and scientific data.

Prospective Comparison of F-18 Choline PET/CT Scan Versus Axial MRI for Detecting Bone Metastasis in Biochemically Relapsed Prostate Cancer Patients

We compared fluor-18 choline positron emission tomography/computed tomography (PET/CT) and axial skeleton magnetic resonance imaging (MRI) prospectively obtained for the detection of bone metastases in non-castrated patients with biochemically recurrent prostate cancer following primary treatment. PET/CT was performed 45 min post-injection of 3-4 MBq/kg F-18 methyl choline. MRI included T1- and fluid sensitive T2-weighted images of the spine and pelvis. Readers were initially blinded from other results and all scans underwent independent double reading. The best valuable comparator (BVC) defined the metastatic status. On the basis of the BVC, 15 out of 64 patients presented with 24 bone metastases. On a patient level, the sensitivity and specificity of MRI and PET were not significantly different. On a lesion level, the sensitivity of MRI was significantly better compared to PET, and the specificity did not differ significantly. In conclusion, axial MRI is an interesting screening tool for the detection of bone metastases because of its low probability of false negative results. However, F-18 choline PET is a valuable addition as it can overrule false positive MRI results and detect non-axial metastases.

Risk stratification in oligometastatic prostate cancer: where are we and what do we need?

PURPOSE OF REVIEW

The oligometastatic disease state was initially described over 20 years ago as an 'intermediate' stage in metastatic cancer progression potentially amenable to curative treatment. Interest in identifying men with oligometastatic disease that may be cured has been increasing. However, whether there truly is a distinct oligometastatic state requires prospective validation, and a risk stratification system based on clinical and genomic factors is needed.

RECENT FINDINGS

We reviewed the existing literature, including 11 ongoing prospective clinical trials, defining the oligometastatic state. We identified specific areas of need including ensuring consensus on the definition of oligometastatic disease and identifying the optimal imaging modality for oligometastatic disease. We identified clinical factors associated with disease aggressiveness in the hormone sensitive metastatic setting, but clinical and molecular risk factors for the oligometastatic setting remain undefined.

SUMMARY

Although risk prediction systems for men with oligometastatic prostate cancer are currently lacking, ongoing interest in this disease state and current clinical trials prospectively assessing biologic relevance, optimal imaging, treatment approaches, and predictive markers, including genomic classification, will provide the data necessary to develop a clinically relevant risk stratification system for the oligometastatic disease state.

Metastasis-Free Survival Is a Strong Surrogate of Overall Survival in Localized Prostate Cancer

Purpose Adjuvant therapy for intermediate-risk and high-risk localized prostate cancer decreases the number of deaths from this disease. Surrogates for overall survival (OS) could expedite the evaluation of new adjuvant therapies. Methods By June 2013, 102 completed or ongoing randomized trials were identified and individual patient data were collected from 28 trials with 28,905 patients. Disease-free survival (DFS) and metastasis-free survival (MFS) were determined for 21,140 patients from 24 trials and 12,712 patients from 19 trials, respectively. We evaluated the surrogacy of DFS and MFS for OS by using a two-stage meta-analytic validation model by determining the correlation of an intermediate clinical end point with OS and the correlation of treatment effects on both the intermediate clinical end point and OS. Results Trials enrolled patients from 1987 to 2011. After a median follow-up of 10 years, 45% of 21,140 men and 45% of 12,712 men experienced a DFS and MFS event, respectively. For DFS and MFS, 61% and 90% of the patients, respectively, were from radiation trials, and 63% and 66%, respectively, had high-risk disease. At the patient level, Kendall's τ correlation with OS was 0.85 and 0.91 for DFS and MFS, respectively. At the trial level, R² was 0.86 (95% CI, 0.78 to 0.90) and 0.83 (95% CI, 0.71 to 0.88) from weighted linear regression of 8-year OS rates versus 5-year DFS and MFS rates, respectively. Treatment effects-measured by log hazard ratios-for the surrogates and OS were well correlated ( R², 0.73 [95% CI, 0.53 to 0.82] for DFS and 0.92 [95% CI, 0.81 to 0.95] for MFS). Conclusion MFS is a strong surrogate for OS for localized prostate cancer that is associated with a significant risk of death from prostate cancer.