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

99mTcPSMA-radioguided surgery in oligorecurrent prostate cancer: the randomised TRACE-II trial

OBJECTIVE

To investigate whether combination treatment of prostate-specific membrane antigen (PSMA)-based radioguided surgery (RGS) with short-term androgen deprivation therapy (ADT) improves oncological outcomes in men with oligorecurrent prostate cancer (PCa) as compared to treatment with short-term ADT only.

METHODS

The TRACE-II study is an investigator-initiated, prospective, randomised controlled clinical trial. Patients (aged >18 years) with hormone-sensitive recurrent PCa after radical prostatectomy or radiotherapy (brachytherapy or external beam radiotherapy), with involvement of ≤2 lymph nodes or local oligorecurrent disease within the pelvis as determined by PSMA positron emission tomography (PET)/computed tomography (CT) are randomly assigned in a 1:1 ratio between 6-month ADT (Arm A) or 6-month ADT plus RGS (Arm B). The primary objective is to determine clinical progression-free survival (CPFS) at 24 months. After PSMA-RGS, CPFS is defined as the time between the start of treatment and the appearance of a re-recurrence (any N1 or M1) as suggested by PSMA-PET/CT or symptoms related to progressive PCa, or death from any cause. The secondary objectives include metastasis-free survival at 2, 5 and 10 years, biochemical progression-free survival at 2 years, and patient-reported quality of life at 2, 5 and 10 years. A total of 60 patients, 30 per arm, will be included. The trial is powered (80%) to detect at least a 30% absolute difference in CPFS between the two study arms in the period 2 years after randomisation. We expect to enrol the required participants in 3 years. The study has an expected duration of 5 years in total.

CONCLUSIONS

Combining RGS with short-term ADT might be oncologically beneficial for patients with oligorecurrent PCa. In this first randomised controlled trial, we are investigating the potential oncological benefits of this combined treatment, while also focusing on maintaining quality of life.

Protocol for CHAMPION study: a prospective study of maximal-cytoreductive therapies for patients with de novo metastatic hormone-sensitive prostate cancer who achieve oligopersistent metastases during systemic treatment with apalutamide plus androgen deprivation therapy

BACKGROUND

The proposed trial is to examine the feasibility of prostate-specific membrane antigen (PSMA) positron emission tomography/computed tomography (PET/CT)-guided cytoreduction plus apalutamide and androgen deprivation therapy (ADT) for newly diagnosed metastatic hormone-sensitive prostate cancer (mHSPC) at oligometastatic state.

METHODS

CHAMPION (NCT05717582) is an open-label, single-arm, phase II trial, planning to enroll newly diagnosed mHSPC cases with oligometastases (≤ 10 distant metastatic sites in conventional imaging). Patients will receive 6 cycles of apalutamide plus ADT. Patients with oligometastatic disease at PSMA PET/CT after 3 treatment cycles will receive cytoreductive radical prostatectomy. PSMA PET/CT-guided metastasis-directed external radiation therapy will be determined by the investigators. Apalutamide plus ADT will be continued for 2 weeks postoperatively. The primary endpoint is the proportion of patients with undetectable prostate-specific antigen (PSA), no disease progression, and no symptom deterioration after 6 cycles of apalutamide plus ADT. Secondary endpoints include the percentage of patients with PSA ≤ 0.2 ng/mL and oligometastases by the end of 3 treatment cycles, PSA response rate, and safety. Fleming's two-stage group sequential design will be adopted in the study, where the null hypothesis is that the rate of patients with an undetectable PSA is ≤ 40% after 6 cycles of treatment, while the alternate hypothesis is an undetectable PSA of > 60%; with one-sided α = 0.05, power = 0.80, and an assumed dropout rate of 10%, the required number of patients for an effective analysis is 47. Enrolment in the study commenced in May 2023.

DISCUSSION

The multi-modal therapy based on treatment response may improve the prognosis of newly diagnosed mHSPC patients with oligometastases.

TRIAL REGISTRATION

The study is registered with Clinical Trials.Gov (NCT05717582). Registered on 8th February 2023.

[Salvage lymphadenectomy for recurrent prostate cancer]

Prostate-specific membrane antigen (PSMA)-based positron emission tomography (PET) imaging allows early detection of metastases in patients with biochemical recurrence. Salvage lymphadenectomy became a widely used method of metastasis-directed treatment. Retrospective analyses show that a low prostate-specific antigen (PSA) value and presence of no more than two affected lymph nodes within the pelvis are factors associated with a good outcome. In all, 40-80% of patients achieve a complete biochemical response with a mean time without biochemical recurrence of 8 months and a prolonged treatment-free interval. About 10% of patients with a complete biochemical response will live without recurrence after 10 years. The utilization of PSMA-radioguided surgery increases the likelihood of intraoperative detection of suspicious affected lymph nodes. Complications can mostly be avoided by prudent patient selection and surgical expertise.

De-Escalation of Therapy for Prostate Cancer

Prostate cancer (PCa) is the second most commonly diagnosed cancer in men with around 1.4 million new cases every year. In patients with localized disease, management options include active surveillance (AS), radical prostatectomy (RP; with or without pelvic lymph node dissection), or radiotherapy to the prostate (with or without pelvic irradiation) with or without hormonotherapy. In advanced disease, treatment options include systemic treatment(s) and/or treatment to primary tumour and/or metastasis-directed therapies (MDTs). Specifically, in advanced stage, the current trend is earlier intensification of treatment such as dual or triple combination systemic treatments or adding treatment to primary and MDT to systemic treatment. However, earlier treatment intensification comes with the cost of increased morbidity and mortality resulting from drug-/treatment-related side effects. The main goal is and should be to provide the best possible care and oncologic outcomes with minimum possible side effects. This chapter will explore emerging possibilities to de-escalate treatment in PCa driven by enhanced insights into disease biology and the natural course of PCa such as AS in intermediate-risk disease or salvage versus adjuvant radiotherapy in post-RP patients. Considerations arising from advancements in PCa imaging and technological advancements in surgical and radiation therapy techniques including omitting pelvic lymph node dissection in the era of prostate-specific membrane antigen positron emitting tomography, the potential of MDT to delay/omit systemic treatment in metachronous oligorecurrence, and the efficacy of hypofractionation schemes compared with conventional fractionated radiotherapy will be discussed.

Prevalence of bilateral loco-regional spread in unilateral pelvic PSMA PET positive recurrent prostate cancer

BACKGROUND

Defining the best surgical template for salvage lymph node dissection (SLND) in patients exhibiting unilateral prostate cancer (PCa) recurrence in pelvic lymph nodes (LNs) is an unmet need. We assessed the risk of missing contralateral nodal recurrence in patients with unilateral positive PSMA-PET who were treated with bilateral PSMA-radioguided (RGS) SLND.

METHODS

Patients who consecutively underwent bilateral PSMA-radioguided SLND for PCa recurrence between April 2014 and January 2023 were identified. We compared PSMA PET findings with the number and the location of PCa LN metastases of the final pathological report. Univariable logistic regression models to try to predict contralateral missed disease were performed.

RESULTS

Sixty patients were identified. At PSMA-RGS, the median PSA level was 0.71 ng/mL (IQR: 0.38-2.28). At PSMA-PET pre-SLND, 49 (82%) patients had unilateral exclusively pelvic lesions, 2 (3%) had unilateral positive nodes at the level of the common iliac arteries, and 9 (15%) had unilateral positive nodes in both levels. Final pathology revealed unilateral LN involvement in 43 (72%), a negative report in 3 (5%), and bilateral positive lesions in 14 (23%) patients. In the univariable logistic regression models, none of the tested factors showed influence on missing contralateral lesions. Four patients out of 35 (11%) with one positive LN at PSMA-PET had bilateral PCa recurrence.

CONCLUSIONS

Patients with one-sided positive LNs on PSMA PET can be considered for a unilateral PSMA-radioguided SLND template with the caveat that about a quarter of patients ultimately have bilateral positive LNs. Larger prospective randomized trials are needed to confirm our findings.

The diagnosis and treatment of castrate-sensitive oligometastatic prostate cancer: A review

BACKGROUND

Oligometastatic prostate cancer (OMPCa) is emerging as a transitional disease state between localized and polymetastatic disease. This review will assess the current knowledge of castrate-sensitive OMPCa.

METHODS

A review of the current literature was performed to summarize the definition and classification of OMPCa, assess the diagnostic methods and imaging modalities utilized, and to review the treatment options and outcomes. We further identify gaps in knowledge and areas for future research.

RESULTS

Currently there is no unified definition of OMPCa. National guidelines mostly recommend systemic therapies without distinguishing oligometastatic and polymetastatic disease. Next generation imaging is more sensitive than conventional imaging and has led to early detection of metastases at initial diagnosis or recurrence. While mostly retrospective in nature, recent studies suggest that treatment (surgical or radiation) of the primary tumor and/or metastatic sites might delay initiation of androgen deprivation therapy while increasing survival in selected patients.

CONCLUSIONS

Prospective data are required to better assess the incremental improvement in survival and quality of life achieved with various treatment strategies in patients with OMPCa.

[Opportunities for prostate-specific membrane antigen hybrid imaging in prostate cancer]

Prostate-specific membrane antigen (PSMA) hybrid imaging is a promising new technique gaining importance in the field of prostate cancer (PCa) diagnosis and treatment planning. By combining PSMA radioligands and computed tomography (CT) or magnetic resonance imaging (MRI), PSMA hybrid imaging opens up new diagnostic opportunities. PSMA-PET/CT (PET: positron-emission tomography) is already well established in high-risk PCa for primary staging and tumor localization when biochemical recurrence occurs. Further potential indications for PSMA-PET/CT include tumor detection in the initial work-up before a rebiopsy with improved accuracy, the identification of target structures for precise local treatment in recurrent PCa (salvage radiotherapy or radio-guided surgery) as well as a prediction of response to PSMA radioligand therapy. This narrative review is based on a recent literature search and aims to highlight the opportunities of PSMA imaging in different disease stages of PCa.

PSMA hybrid imaging in prostate cancer - current applications and perspectives

BACKGROUND

Prostate cancer (PCa) is the most common malignancy in men and the second most common tumor-associated cause of death in the male population in Germany. Prostate-specific membrane antigen (PSMA)-targeted hybrid imaging using positron emission tomography (PET) in combination with CT or MRI represents a comparably new method that gained increasing importance in the diagnostic process of PCa in recent years.

METHOD

Current applications of PSMA hybrid imaging were summarized according to the German and European guidelines on PCa. New developments were elaborated based on a literature review of PubMed conducted in 10/22.

RESULTS

PSMA-PET/CT demonstrated higher detection rates for metastases in high-risk PCa and recurrent PCa after primary therapy than established imaging methods (CT, MRI, and bone scan). Despite promising results from prospective trials in both scenarios and substantial influence on clinical decision making, data regarding the influence of PSMA-PET on PCa-specific and overall survival are still lacking. Hence, PSMA PET/CT is recommended with a "weak" strength rating in most situations. However, its importance in new treatment options like metastasis-directed therapy or PSMA-radioligand therapy expands the scope of PSMA-PET in the clinical routine.

CONCLUSION

PSMA-targeting hybrid imaging represents the most sensitive diagnostic test in several stages of PCa and allows the development of new treatment strategies. Prospective studies are needed to evaluate the influence of PSMA-PET on patient survival.

KEY POINTS

· PSMA-PET/CT is superior to conventional imaging in the primary staging of high-risk prostate cancer.. · PSMA hybrid imaging can detect metastases in patients with biochemical recurrence at low PSA values.. · Clinical decision making is frequently influenced by results of PSMA-PET/CT..

CITATION FORMAT

· Koehler D, Berliner C, Shenas F et al. PSMA hybrid imaging in prostate cancer - current applications and perspectives. Fortschr Röntgenstr 2023; 195: 1001 - 1008.

Safety and efficiency of repeat salvage lymph node dissection for recurrence of prostate cancer using PSMA-radioguided surgery (RGS) after prior salvage lymph node dissection with or without initial RGS support

BACKGROUND AND OBJECTIVE

Metastasis-directed therapy is a feasible option for low PSA, recurrent locoregional metastatic prostate cancer. After initial salvage surgery, patients with good response might consider a repeat salvage surgery in case of recurrent, isolated, and PSMA-positive metastases. This analysis aimed to evaluate the oncological outcome and safety of repeat PSMA-targeted radioguided surgery (RGS) after either prior RGS or "standard" salvage lymph node dissection (SLND).

MATERIALS AND METHODS

We identified 37 patients undergoing repeat RGS after prior SLND (n = 21) (SLND-RGS) or prior RGS (n = 16) (RGS-RGS) between 2014 and 2021 after initial radical prostatectomy with or without pelvic radiation therapy at two German tertiary referral centers. Kaplan-Meier analyses and uni-/multivariable Cox regression models were used to investigate factors associated with biochemical recurrence-free survival (BRFS) and treatment-free survival (TFS) after repeat salvage surgery.

RESULTS AND LIMITATIONS

Complete Biochemical Response (cBR, PSA < 0.2 ng/ml) was observed in 20/32 patients (5 NA). Median overall BRFS [95% confidence interval (CI)] after repeat salvage surgery was 10.8 months (mo) (5.3-22). On multivariable regression, only age (HR 1.09, 95% CI 1.01-1.17) and preoperative PSA (HR 1.23, 95% CI 1.01-1.50) were associated with shorter BRFS, although PSA (HR 1.16, 95% CI 0.99-1.36) did not achieve significant predictor status in univariable analysis before (p value = 0.07). Overall, one year after second salvage surgery, 89% of the patients (number at risk: 19) did not receive additional treatment and median TFS was not reached. Clavien-Dindo grade > 3a complications were observed in 8% (3/37 patients). Limitations are the retrospective evaluation, heterogeneous SLND procedures, lack of long-term follow-up data, and small cohort size.

CONCLUSION

In this study, repeat RGS was safe and provided clinically meaningful biochemical recurrence- and treatment-free intervals for selected cases. Patients having low preoperative PSA seemed to benefit most of repeat RGS, irrespective of prior SLND or RGS or the time from initial RP/first salvage surgery.

Salvage lymphadenectomy after primary therapy with curative intent for prostate cancer

PURPOSE OF REVIEW

To provide a summary of the current literature on salvage lymph node dissection (sLND) in patients with nodal recurrent prostate cancer (PCa) with focus on imaging, the extent of sLND and oncologic outcomes.

RECENT FINDINGS

The clinical practice guidelines recommend performing PET/CT in patients with biochemical recurrence (BCR) after primary therapy. PSMA PET/CT has demonstrated superiority over choline PET/CT and MRI, especially at low prostate-specific antigen (PSA) levels. Although the heterogeneity in available literature does not allow standardization of surgical templates for sLND and PET/CT scan can guide the extent of surgical dissection, an anatomically defined extended template is typically considered. Radio-guided surgery (RGS) suggests an improved positive lymph node yield compared with standard sLND. However, long-term data are needed to evaluate the oncologic impact of sLND. The main aims of sLND are to delay recurrence and to postpone the need for systemic therapy. Available evidence suggests that around 40-80% of men can achieve complete biochemical response after sLND and 10-30% remain BCR free after 5 years. Robotic sLND might represent an option to reduce the risk of complications without compromising oncological outcomes; validation in controlled prospective studies is, however, needed.

SUMMARY

sLND is a valid treatment option for patients with nodal recurrence only after primary therapy for PCa. Further optimization of patient selection based on highly sensitive and specific imaging and clinical factors remains an unmet need. To maximize the benefit of this approach, sLND should be discussed with patients who harbor lymph node-only recurrence after primary therapy in a shared decision-making.

A Retrospective Multicenter Analysis of the Incidence of Bone-Only Disease at PSMA PET/CT in Castration Resistant Prostate Cancer Patients

PSMA PET/CT has unprecedented accuracy for localization of initial or recurrent prostate cancer (PC), which can be applied in a metastasis-directed therapy approach. PSMA PET/CT (PET) also has a role in the selection of patients for metastasis-directed therapy or radioligand therapy and therapy assessment in CRPC patients. The purpose of this multicenter retrospective study was to determine the incidence of bone-only metastasis in CRPC patients who underwent PSMA PET/CT for restaging, as well as identifying potential predictors of bone-only PET positivity. The study analyzed data from 179 patients from two centers in Essen and Bologna. Results showed that 20.1% of the patients had PSMA uptake only in the bone, with the most frequent lesions located in the vertebrae, ribs, and hip bone. Half half of the patients showed oligo disease in bone and may benefit from a bone-metastasis-directed therapy. Initial positive nodal status and solitary ADT were shown to be negative predictors of osseous metastasis. The role of PSMA PET/TC in this patient population needs to be further explored in terms of its role in the evaluation and adoption of bone-specific therapies.

Management of Patients with Advanced Prostate Cancer. Part I: Intermediate-/High-risk and Locally Advanced Disease, Biochemical Relapse, and Side Effects of Hormonal Treatment: Report of the Advanced Prostate Cancer Consensus Conference 2022

BACKGROUND

Innovations in imaging and molecular characterisation and the evolution of new therapies have improved outcomes in advanced prostate cancer. Nonetheless, we continue to lack high-level evidence on a variety of clinical topics that greatly impact daily practice. To supplement evidence-based guidelines, the 2022 Advanced Prostate Cancer Consensus Conference (APCCC 2022) surveyed experts about key dilemmas in clinical management.

OBJECTIVE

To present consensus voting results for select questions from APCCC 2022.

DESIGN, SETTING, AND PARTICIPANTS

Before the conference, a panel of 117 international prostate cancer experts used a modified Delphi process to develop 198 multiple-choice consensus questions on (1) intermediate- and high-risk and locally advanced prostate cancer, (2) biochemical recurrence after local treatment, (3) side effects from hormonal therapies, (4) metastatic hormone-sensitive prostate cancer, (5) nonmetastatic castration-resistant prostate cancer, (6) metastatic castration-resistant prostate cancer, and (7) oligometastatic and oligoprogressive prostate cancer. Before the conference, these questions were administered via a web-based survey to the 105 physician panel members ("panellists") who directly engage in prostate cancer treatment decision-making. Herein, we present results for the 82 questions on topics 1-3.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Consensus was defined as ≥75% agreement, with strong consensus defined as ≥90% agreement.

RESULTS AND LIMITATIONS

The voting results reveal varying degrees of consensus, as is discussed in this article and shown in the detailed results in the Supplementary material. The findings reflect the opinions of an international panel of experts and did not incorporate a formal literature review and meta-analysis.

CONCLUSIONS

These voting results by a panel of international experts in advanced prostate cancer can help physicians and patients navigate controversial areas of clinical management for which high-level evidence is scant or conflicting. The findings can also help funders and policymakers prioritise areas for future research. Diagnostic and treatment decisions should always be individualised based on patient and cancer characteristics (disease extent and location, treatment history, comorbidities, and patient preferences) and should incorporate current and emerging clinical evidence, therapeutic guidelines, and logistic and economic factors. Enrolment in clinical trials is always strongly encouraged. Importantly, APCCC 2022 once again identified important gaps (areas of nonconsensus) that merit evaluation in specifically designed trials.

PATIENT SUMMARY

The Advanced Prostate Cancer Consensus Conference (APCCC) provides a forum to discuss and debate current diagnostic and treatment options for patients with advanced prostate cancer. The conference aims to share the knowledge of international experts in prostate cancer with health care providers and patients worldwide. At each APCCC, a panel of physician experts vote in response to multiple-choice questions about their clinical opinions and approaches to managing advanced prostate cancer. This report presents voting results for the subset of questions pertaining to intermediate- and high-risk and locally advanced prostate cancer, biochemical relapse after definitive treatment, advanced (next-generation) imaging, and management of side effects caused by hormonal therapies. The results provide a practical guide to help clinicians and patients discuss treatment options as part of shared multidisciplinary decision-making. The findings may be especially useful when there is little or no high-level evidence to guide treatment decisions.

Combining PSA and PET features to select candidates for salvage lymph node dissection in recurrent prostate cancer

Objective

To evaluate the relationship between pre-operative PSA value, 68Ga-prostate-specific-membrane-antigen (PSMA) PET performance and oncologic outcomes after salvage lymph node dissection (sLND) for biochemical recurrent prostate cancer (PCa).

Patients and methods

The study included 164 patients diagnosed with ≤2 pelvic lymph-node recurrence(s) of PCa documented on 68Ga-PSMA PET scan and treated with pelvic ± retroperitoneal sLND at 11 high-volume centres between 2012 and 2019. Pathologic findings were correlated to PSA values at time of sLND, categorized in early (<0.5 ng/ml), low (0.5-0.99 ng/ml), moderate (1-1.5 ng/ml) and high (>1.5 ng/ml). Clinical recurrence (CR)-free survival after sLND was calculated using multivariable analyses and plotted over pre-operative PSA value.

Results

Median [interquartile range (IQR)] PSA at sLND was 1.1 (0.6, 2.0) ng/ml, and 131 (80%) patients had one positive spot at PET scan. All patients received pelvic sLND, whereas 91 (55%) men received also retroperitoneal dissection. Median (IQR) number of node removed was 15 (6, 28). The rate of positive pathology increased as a function of pre-operative PSA value, with highest rates for patients with pre-operative PSA > 1.5 ng/ml (pelvic-only sLNDs: 84%; pelvic + retroperitoneal sLNDs: 90%). After sLND, PSA ≤ 0.3 ng/ml was detected in 67 (41%) men. On multivariable analyses, pre-operative PSA was associated with PSA response (p < 0.0001). There were 51 CRs after sLND. After adjusting for confounders, we found a significant, non-linear relationship between PSA level at sLND and the 12-month CR-free survival (p < 0.0001), with the highest probability of freedom from CR for patients who received sLND at PSA level ≥1 ng/ml.

Conclusions

In case of PET-detected nodal recurrences amenable to sLND, salvage surgery was associated with the highest short-term oncologic outcomes when performed in men with PSA ≥ 1 ng/ml. Awaiting confirmatory data from prospective trials, these findings may help physicians to optimize the timing for 68Ga-PSMA PET in biochemical recurrent PCa.

Cohort Study of Oligorecurrent Prostate Cancer Patients: Oncological Outcomes of Patients Treated with Salvage Lymph Node Dissection via Prostate-specific Membrane Antigen-radioguided Surgery

BACKGROUND

In a subset of patients with recurrent oligometastatic prostate cancer (PCa) salvage surgery with prostate-specific membrane antigen (PSMA)-targeted radioguidance (PSMA-RGS) might be of value.

OBJECTIVE

To evaluate the oncological outcomes of salvage PSMA-RGS and determine the predictive preoperative factors of improved outcomes.

DESIGN, SETTING, AND PARTICIPANTS

A cohort study of oligorecurrent PCa patients with biochemical recurrence (BCR) after radical prostatectomy and imaging with PSMA positron emission tomography (PET), treated with PSMA-RGS in two tertiary care centers (2014-2020), was conducted.

INTERVENTION

PSMA-RGS.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Kaplan-Meier and multivariable Cox regression models were used to assess BCR-free (BFS) and therapy-free (TFS) survival. Postoperative complications were classified according to Clavien-Dindo.

RESULTS AND LIMITATIONS

Overall, 364 patients without concomitant treatment were assessed. At PSMA-RGS, metastatic soft-tissue PCa lesions were removed in 343 (94%) patients. At 2-16 wk after PSMA-RGS, 165 patients reached a prostate-specific antigen (PSA) level of <0.2 ng/ml. Within 3 mo, 24 (6.6%) patients suffered from Clavien-Dindo complications grade III-IV. At 2 yr, BFS and TFS rates were 32% and 58%, respectively. In multivariable analyses, higher preoperative PSA (hazard ratio [HR]: 1.07, 95% confidence interval [CI]: 1.02-1.12), higher number of PSMA-avid lesions (HR: 1.23, CI: 1.08-1.40), multiple (pelvic plus retroperitoneal) localizations (HR: 1.90, CI: 1.23-2.95), and retroperitoneal localization (HR: 2.04, CI: 1.31-3.18) of lesions in preoperative imaging were independent predictors of BCR after PSMA-RGS. The main limitation is the lack of a control group.

CONCLUSIONS

As salvage surgery in oligorecurrent PCa currently constitutes an experimental treatment approach, careful patient selection is mandatory based on life expectancy, low PSA values, and low number of PSMA PET-avid lesions located in the pelvis.

PATIENT SUMMARY

We looked at the outcomes from prostate cancer patients with recurrent disease after radical prostatectomy. We found that surgery may be an opportunity to prolong treatment-free survival, but patient selection criteria need to be very narrow.

Stereotactic radiotherapy of nodal oligometastases from prostate cancer: a prisma-compliant systematic review

Androgen deprivation therapy (ADT) is the standard treatment of metastatic prostate cancer (PCa). However, metastases-directed therapies can delay the initiation or switch of systemic treatments and allow local control (LC) and prolonged progression-free survival (PFS), particularly in patients with lymph nodes (LN) oligometastases. We performed a systematic review on stereotactic body radiotherapy (SBRT) in this setting. Papers reporting LC and/or PFS were selected. Data on ADT-free survival, overall survival, and toxicity were also collected from the selected studies. Fifteen studies were eligible (414 patients), 14 of them were retrospective analyses. A high heterogeneity was observed in terms of patient selection and treatment. In one study SBRT was delivered as a single 20 Gy fraction, while in the others the median total dose ranged between 24 and 40 Gy delivered in 3-6 fractions. LC and PFS were reported in 15 and 12 papers, respectively. LC was reported as a crude percentage in 13 studies, with 100% rate in seven and 63.2-98.0% in six reports. Five studies reported actuarial LC (2-year LC: 70.0-100%). PFS was reported as a crude rate in 11 studies (range 27.3-68.8%). Actuarial 2-year PFS was reported in four studies (range 30.0-50.0%). SBRT tolerability was excellent, with only two patients with grade 3 acute toxicity and two patients with grade 3 late toxicity. SBRT for LN oligorecurrences from PCa in safe and provides optimal LC. However, the long-term effect on PFS and OS is still unclear as well as which patients are the best candidate for this approach.

Validation of 18F-rhPSMA-7 and 18F-rhPSMA-7.3 PET Imaging Results with Histopathology from Salvage Surgery in Patients with Biochemical Recurrence of Prostate Cancer

¹⁸F-rhPSMA-7, and its single diastereoisomer form, ¹⁸F-rhPSMA-7.3, are prostate-specific membrane antigen (PSMA)-targeting radiopharmaceuticals. Here, we investigated their accuracy for the assessment of lymph node (LN) metastases validated by histopathology. Methods: Data from 58 patients with biochemical recurrence of prostate cancer after radical prostatectomy receiving salvage surgery after PET imaging with ¹⁸F-rhPSMA-7 or ¹⁸F-rhPSMA-7.3 were retrospectively reviewed. Two nuclear medicine physicians reviewed all PET scans and morphologic imaging in consensus. Readers were masked from the results of histopathology. PET and morphologic imaging were correlated with histopathology from resected LNs. Results: In 75 of 150 resected regions in 54 of 58 patients, tumor lesions were present in histopathology. The template-based specificity of PET (¹⁸F-rhPSMA-7 and ¹⁸F-rhPSMA-7.3 combined) and morphologic imaging was 93.3% and 100%, respectively. However, ¹⁸F-rhPSMA-7 and ¹⁸F-rhPSMA-7.3 PET detected metastases in 61 of 75 histopathologically proven metastatic LN fields (81.3%) whereas morphologic imaging was positive in only 9 of 75 (12.0%). The positive predictive value was 92.4% for ¹⁸F-rhPSMA-7 and ¹⁸F-rhPSMA-7.3 PET and 100% for morphologic imaging. ¹⁸F-rhPSMA-7 and ¹⁸F-rhPSMA-7.3 PET performance was significantly superior to morphologic imaging (difference in the areas under the receiver-operating-characteristic curves, 0.222; 95% CI, 0.147-0.298; P < 0.001). The mean size of PET-positive and histologically confirmed LN metastases was 6.3 ± 3.1 mm (range, 2-15 mm) compared with a mean size of 9.8 ± 2.5 mm (range, 7-15 mm) on morphologic imaging. Conclusion: ¹⁸F-rhPSMA-7 and ¹⁸F-rhPSMA-7.3 PET offer a high positive predictive value comparable to that reported for ⁶⁸Ga-PSMA-11 and represent a valuable tool for guiding salvage lymphadenectomy.

The current role of precision surgery in oligometastatic prostate cancer

Oligometastatic prostate cancer (omPCa) is a novel intermediate disease state characterized by a limited volume of metastatic cells and specific locations. Accurate staging is paramount to unmask oligometastatic disease, as provided by prostate-specific membrane antigen-positron emission tomography. Driven by the results of prospective trials employing conventional and/or modern staging modalities, the treatment landscape of omPCa has rapidly evolved over the last years. Several treatment-related questions comprising the concept of precision strikes are under development. For example, beyond systemic therapy, cohort studies have found that cytoreductive radical prostatectomy (CRP) can confer a survival benefit in select patients with omPCa. More importantly, CRP has been consistently shown to improve long-term local symptoms when the tumor progresses across disease states due to resistance to systemic therapies. Metastasis-directed treatments have also emerged as a promising treatment option due to the visibility of oligometastatic disease and new technologies as well as treatment strategies to target the novel PCa colonies. Whether metastases are present at primary cancer diagnosis or detected upon biochemical recurrence after treatment with curative intent, targeted yet decisive elimination of disseminated tumor cell hotspots is thought to improve survival outcomes. One such strategy is salvage lymph node dissection in oligorecurrent PCa which can alter the natural history of progressive PCa. In this review, we will highlight how refinements in modern staging modalities change the classification and treatment of (oligo-)metastatic PCa. Further, we will also discuss the current role and future directions of precision surgery in omPCa.

Role of Local Treatment for Oligometastasis: A Comparability-Based Meta-Analysis

PURPOSE

We intend to investigate the oncological efficacy and feasibility of local consolidative therapy (LCT) through a meta-analysis method.

MATERIALS AND METHODS

Four databases including PubMed, MEDLINE, Embase, and Cochrane library were searched. Target studies are controlled trials comparing outcomes of LCT versus a control group. Primary endpoints are overall survival (OS) and progression-free survival (PFS).

RESULTS

A total of 54 studies involving 7,242 patients were included. Pooled analyses showed that the LCT arm could achieve improved OS with pooled odds ratio of 2.896 (95% confidence interval [CI], 2.377 to 3.528; p < 0.001). Regarding PFS, pooled analyses showed pooled odds ratio of 3.045 (95% CI, 2.356 to 3.937; p < 0.001) in favor of the LCT arm. In the subgroup analyses including the studies with reliable comparability (e.g. randomized studies or intentionally matched studies without significant favorable prognosticator in LCT arms), pooled odds ratio was 2.548 (95% CI, 1.808 to 3.591; p < 0.001) favoring the LCT arm regarding OS. Regarding PFS, pooled OR was 2.656 (95% CI, 1.713 to 4.120; p < 0.001) which also favored the LCT arm. Subgroup analyses limited to the randomized controlled trials (RCT) were also performed and pooled odds ratios on OS and PFS were 1.535 (95% CI, 1.082 to 2.177; p=0.016) and 1.668 (95% CI, 1.187 to 2.344; p=0.003). The rates of grade ≥ 3 complications related to LCT was mostly low (< 10%) and not significantly higher compared to the control arm.

CONCLUSION

Pooled analyses results of all included studies, selected studies with reliable comparability, and RCT's demonstrated the survival benefit of LCT. These consistent results suggest that LCT was beneficial to the patients with oligometastasis.

Oligometastatic Lymph Node Recurrence Detected Using 18F-PSMA-1007 PET/CT in a Patient With Castration-resistant Prostate Cancer After Radiation Therapy

BACKGROUND/AIM

Prostate cancer (PC) is one of the most common types of cancer in men worldwide. Most patients with metastatic PC are treated with androgen deprivation therapy (ADT) using luteinizing hormone-releasing hormone agonists and antagonists as first-line therapy. The majority of PC patients develop a castration-resistant PC (CRPC), which eventually leads to high mortality with poor prognosis, despite new targeted therapies. However, given that oligometastatic recurrence may enable local therapy in CRPC, accurate detection of metastatic lesions may improve clinical outcomes in patients with CRPC.

CASE REPORT

We report the case of an 83-year-old man with CRPC. ¹⁸Fluorine-prostate-specific membrane antigen-1007 positron emission tomography/ computed tomography (¹⁸F-PSMA-1007 PET/CT) revealed weak physiological PSMA accumulation in the prostate and strong accumulation not only in the internal iliac lymph node but also in the two obturator lymph nodes that could not be detected with conventional CT or magnetic resonance imaging. Prostatic re-biopsy revealed no prostate malignancy. Under the diagnosis of oligometastases in the pelvic lymph nodes, the patient underwent laparoscopic pelvic lymph node dissection, which revealed lymph node metastases in two obturator lymph nodes and the internal iliac lymph node, corresponding to the PSMA accumulation sites. The patient experienced at least 7 months of recurrence-free duration without additional treatment.

CONCLUSION

This study indicates a novel approach to oligometastatic CRPC by means of accurate staging with ¹⁸F-PSMA-1007 PET/CT.

Management of Biochemical Recurrence of Prostate Cancer After Curative Treatment: A Focus on Older Patients

Following a treatment with curative intent, a biochemical recurrence may be diagnosed, often many years after the primary treatment. The consequences of this relapse on survival are very heterogeneous. The expected specific survival at relapse is above 50% at 10 years. Therefore, its management needs to be balanced with the individual life expectancy. The relapse needs to be categorized as either a low- or high-risk category. The latter has to be considered for salvage therapy, provided the individual life expectancy is long enough. It is evaluated through an initial geriatric assessment, starting with the G8 score as well as the mini-Cog. A comprehensive geriatric assessment might be needed based on the G8 score. Patients will then be categorized as either fit, vulnerable, or frail. If a local salvage therapy is considered, the relapse localization might be of interest in some situations. Available salvage therapies in senior adults have nothing special compared to salvage of younger men, except for aggressive local therapy, which might be less well tolerated. The key objective in managing a biochemical recurrence in senior adults is to find the right balance between under- and over-treatment in a shared decision process. In many frail and vulnerable men, a clinically oriented watchful waiting should be preferred, while fit men with an aggressive relapse and a significant life expectancy need an active therapy.

The Role of PSMA PET/CT in the Primary Diagnosis and Follow-Up of Prostate Cancer-A Practical Clinical Review

Simple Summary

The combination of positron emission tomography (PET)-diagnostics with ligands binding to the prostate-specific membrane antigen (PSMA) has been a diagnostic milestone in the situation of biochemical recurrence of prostate cancer and is gaining importance in primary diagnostics, providing a highly specific and sensitive diagnostic method in various clinical situations. However, the clinical application of this method requires a comprehensive knowledge of its advantages and disadvantages, potential pitfalls and influencing factors. This review aims to provide a practical clinical review of the currently available background data on PSMA PET/CT, as well as the clinical implications. Although a large amount of data already exist, a thorough analysis is complicated by study heterogeneity, showing the need for future systematic and prospective research.

Abstract

The importance of PSMA PET/CT in both primary diagnostics and prostate cancer recurrence has grown steadily since its introduction more than a decade ago. Over the past years, a vast amount of data have been published on the diagnostic accuracy and the impact of PSMA PET/CT on patient management. Nevertheless, a large heterogeneity between studies has made reaching a consensus difficult; this review aims to provide a comprehensive clinical review of the available scientific literature, covering the currently known data on physiological and pathological PSMA expression, influencing factors, the differences and pitfalls of various tracers, as well as the clinical implications in initial TNM-staging and in the situation of biochemical recurrence. This review has the objective of providing a practical clinical overview of the advantages and disadvantages of the examination in various clinical situations and the body of knowledge available, as well as open questions still requiring further research.

Completeness of reporting oligometastatic disease characteristics in literature and influence on oligometastatic disease classification using the ESTRO/EORTC nomenclature

BACKGROUND

There is increasing evidence for the integration of locally ablative therapy into multimodality treatment of oligometastatic disease (OMD). To support standardised data collection, analysis, and comparison, a consensus OMD classification based on fundamental disease and treatment characteristics has previously been established. This study investigated the completeness of reporting the proposed OMD characteristics in literature and evaluated whether the proposed OMD classification system can be applied to the historical data.

METHODS

A systematic literature review was performed in Medline, Embase, and Cochrane, searching for prospective and retrospective studies, where SBRT was a treatment component of OMD. Reporting of the OMD characteristics as described in the EORTC/ESTRO classification was analyzed, feasibility to retrospectively classify the proposed OMD states was investigated and the impact of the categorisation on overall survival (OS) was evaluated.

RESULTS

Our study shows incomplete reporting of the proposed OMD characteristics. The most fully reported characteristic was 'type of involved organs' (88/95 studies); 'history of cancer progression' was the least reported (not mentioned in 50/95 studies). Retrospective OMD classification of existing literature was only possible for 7/95 studies. With respect to categorization as de novo, repeat or induced OMD, homogeneous patient cohorts were observed in 21/95 studies, most frequently de novo OMD, in 20 studies. Differences in OS at 2, 3, or 5 years were not statistically significant between the different states. OS was significantly influenced by primary tumor histology, with superior OS observed for prostate cancer and worst OS observed for non-small cell lung cancer.

CONCLUSION

The largely incomplete reporting of the proposed OMD characteristics hampers a retrospective classification of existing literature. To facilitate future comparison of individual studies, as well as validation of the OMD classification, comprehensive reporting of OMD characteristics using standardised terminology is recommended, as proposed by the EORTC/ESTRO classification system and following ESTRO-ASTRO consensus.

Ga-68-PSMA-11 PET/CT in Patients with Biochemical Recurrence of Prostate Cancer after Primary Treatment with Curative Intent-Impact of Delayed Imaging

The presence of prostate-specific membrane antigen (PSMA) on prostate cancer cells and its metastases allows its use in diagnostics using PET/CT. The aim of this study was to evaluate the usefulness of delayed phase images in the Ga-68-PSMA-11 PET/CT. Methods: 108 patients with prostate cancer (median age: 68.5 years, range: 49−83) were referred for Ga-68-PSMA-11 PET/CT due to biochemical relapse (PSA (prostate-specific antigen) (3.2 ± 5.4 ng/mL). Examinations were performed at 60 min, with an additional delayed phase of the pelvis region at 120−180 min. Results: The Ga-68-PSMA-11 PET/CT showed lesions in 86/108 (80%) patients; detection rate depending on the PSA level: 0.2 < PSA < 0.5 ng/mL vs. 0.5 ≤ PSA < 1.0 ng/mL vs. 1.0 ≤ PSA < 2.0 ng/mL vs. PSA ≥ 2.0 ng/mL was 56% (standard vs. delay: 56 vs. 56%) vs. 60% (52 vs. 60%) vs. 87% (83 vs. 87%) vs. 82% (77 vs. 82%) of patients, respectively. The delayed phase had an impact on the treatment in 14/86 patients (16%) (p < 0.05): 7 pts increased uptake was seen only after 60 min, which was interpreted as physiological or inflammatory accumulation; the delayed image showed increased accumulation in 7 patients only: 4 in regional lymph nodes, 1 in local recurrence, and 2 patients with local recurrence showed additional foci. Conclusions: Delayed phase of Ga-68-PSMA-11 PET/CT has an impact on treatment management in 16% of patients.

Oligometastatic Prostate Cancer: A Comparison between Multimodality Treatment vs. Androgen Deprivation Therapy Alone

Background: We compared multimodality treatment (MMT, defined as robot-assisted radical prostatectomy (RARP) with androgen deprivation therapy (ADT), with or without adjuvant radiotherapy (RT)) vs. ADT alone in oligometastatic prostate cancer (OPC) patients. Methods: From 2010 to 2018, we identified 74 patients affected by cM1a-b OPC (≤5 metastases). Kaplan−Meier (KM) plots depicted cancer-specific mortality (CSM), disease progression, metastatic castration-resistant PC (mCRPC), and time to second-line systemic therapy rates. Multivariable Cox regression models (MCRMs) focused on disease progression and mCRPC. Results: Forty (54.0%) MMT and thirty-four (46.0%) ADT patients were identified. On KM plots, higher CSM (5.9 vs. 37.1%; p = 0.02), mCRPC (24.0 vs. 62.5%; p < 0.01), and second-line systemic therapy (33.3 vs. 62.5%; p < 0.01) rates were recorded in the ADT group. No statistically significant difference was recorded for disease progression. ForMCRMs adjusted for the metastatic site and PSA, a higher mCRPC rate was recorded in the ADT group. No statistically significant difference was recorded for disease progression. Treatment-related adverse events occurred in 5 (12.5%) MMT vs. 15 (44.1%) ADT patients (p < 0.01). Conclusions: MMT was associated with lower CSM, mCRPC, and second-line therapy rates. A lower rate of treatment-related adverse events was recorded for the MMT group.

Molecular Mechanisms Related with Oligometastatic Prostate Cancer-Is It Just a Matter of Numbers?

During the last decade, the body of knowledge regarding the oligometastatic state has increased exponentially. Several molecular frameworks have been established, aiding our understanding of metastatic spread caused by genetically unstable cells that adapt to a tissue environment which is distant from the primary tumor. In the current narrative review, we provide an overview of the current treatment landscape of oligometastatic cancer, focusing on the current biomarkers used in the identification of true oligometastatic disease and highlighting the impact of molecular imaging on stage shift in different scenarios. Finally, we address current and future directions regarding the use of genetic and epigenetic targeting treatments in oligometastatic prostate cancer.

Implementation of radioguided surgery in prostate cancer

With the development of new imaging technologies and tracers, the applications of radioguided surgery for prostate cancer are growing rapidly. The current paper aims to give an overview of the recent advances of radioguided surgery in the management of prostate cancer. We performed a literature search to give an overview of the current status of radioguided surgery for prostate cancer. Three modalities of radioguided surgery, the sentinel node procedure, Cerenkov Luminescence / beta-radio-guided surgery and radio-guided salvage surgery in recurrent prostate cancer, were reviewed in detail. Radioguided surgery for prostate cancer has shown promising value in the treatment of primary diagnosed prostate cancer and recurrent loco-regional lymph node positive prostate cancer. Advances have been made into minimal invasive (robot-assisted) laparoscopic surgery. The sentinel node procedure for prostate cancer has been further developed and is currently performed with high diagnostic sensitivity. Cerenkov luminescence imaging is a feasible and encouraging technique for intraoperative margin assessment in prostate cancer. Radioguided surgery in recurrent prostate cancer has shown to be feasible, yielding high sensitivity and specificity for detecting small local recurrences and metastases. With the availability of different new tracers, the road has been paved towards clinically feasible radioguided surgery for prostate cancer. Novel technologies now being developed for minimal invasive surgery are speeding up clinical research. Currently, none of the radioguided surgery techniques mentioned have been accepted as standard of care.

Oligometastatic prostatic cancer recurrence: role of salvage lymph node dissection (sLND) and radiation therapy-stereotactic body radiation therapy (RT-SBRT)

PURPOSE OF REVIEW

Metastases directed therapy (MDT) is an increasingly utilized modality in patients with oligometastatic prostate cancer (OMPC) recurrence. The purpose of our review is to discuss the recent literature on the safety and oncologic outcomes of this treatment approach.

RECENT FINDINGS

Metastases directed therapy, in particular, stereotactic body radiation therapy (SBRT) and salvage lymph node dissection (sLND), has shown promising efficacy in patients with OMPC. Many case series report favorable outcomes with MDT as compared to hormonal deprivation therapy alone or surveillance. Of the few case series investigating the use of MDT as part of a multimodality approach in castrate-resistant OMPC, more favorable outcomes in comparison to the use of systemic treatment alone are reported.

SUMMARY

With the recent advances in imaging techniques, particularly molecular imaging, management of OMPC has progressed rapidly in the last few years. The feasibility and benefits of MDT in OMPC have been demonstrated in prospective and retrospective series. Further prospective studies investigating the role of MDT to define optimal patient subgroups and management strategies are warranted.

Combining 68Ga-PSMA-PET/CT-Directed and Elective Radiation Therapy Improves Outcome in Oligorecurrent Prostate Cancer: A Retrospective Multicenter Study

Background

In case of oligo-recurrent prostate cancer (PC) following prostatectomy, ⁶⁸Ga-PSMA-PET/CT can be used to detect a specific site of recurrence and to initiate metastasis-directed radiation therapy (MDT). However, large heterogeneities exist concerning doses, treatment fields and radiation techniques, with some studies reporting focal radiotherapy (RT) to PSMA-PET/CT positive lesions only and other studies using elective RT strategies. We aimed to compare oncological outcomes and toxicity between PET/CT-directed RT (PDRT) and PDRT plus elective RT (eRT; i.e. prostate bed, pelvic or paraaortal nodes) in a large retrospective multicenter study.

Methods

Data of 394 patients with oligo-recurrent ⁶⁸Ga-PSMA-PET/CT-positive PC treated between 04/2013 and 01/2018 in six different academic institutions were evaluated. Primary endpoint was biochemical-recurrence-free survival (bRFS). bRFS was analyzed using Kaplan-Meier survival curves and log rank testing. Uni- and multivariate analyses were performed to determine influence of treatment parameters.

Results

In 204 patients (51.8%) RT was directed only to lesions seen on ⁶⁸Ga-PSMA-PET/CT (PDRT), 190 patients (48.2%) received PDRT plus eRT. PDRT plus eRT was associated with a significantly improved 3-year bRFS compared to PDRT alone (53 vs. 37%; p = 0.001) and remained an independent factor in multivariate analysis (p = 0.006, HR 0.29, 95% CI 0.12-0.68). This effect was more pronounced in the subgroup of patients who were treated with PDRT and elective prostate bed radiotherapy (ePBRT) with a 3-year bRFS of 61% versus 22% (p <0.001). Acute and late toxicity grade ≥3 was 0.8% and 3% after PDRT plus eRT versus no toxicity grade ≥3 after PDRT alone.

Conclusions

In this large cohort of patients with oligo-recurrent prostate cancer, elective irradiation of the pelvic lymphatics and the prostatic bed significantly improved bRFS when added to ⁶⁸Ga-PSMA-PET/CT-guided focal radiotherapy. These findings need to be evaluated in a randomized controlled trial.

A survey among German-speaking radiation oncologists on PET-based radiotherapy of prostate cancer

Background

Positron emission tomography-(PET) has evolved as a powerful tool to guide treatment for prostate cancer (PC). The aim of this survey was to evaluate the acceptance and use of PET—especially with prostate-specific membrane antigen (PSMA) targeting tracers—in clinical routine for radiotherapy (RT) and the impact on target volume definition and dose prescription.

Methods

We developed an online survey, which we distributed via e-mail to members of the German Society of Radiation Oncology (DEGRO). The survey included questions on patterns of care of RT for PC with/without PET. For evaluation of doses we used the equivalent dose at fractionation of 2 Gy with α/β = 1.5 Gy [EQD2(1.5 Gy)].

Results

From 109 participants, 78.9% have the possibility to use PET for RT planning. Most centers use PSMA-targeting tracers (98.8%). In 39.5%, PSMA-PET for biochemical relapse after prior surgery is initiated at PSA ≥ 0.5 ng/mL, while 30.2% will perform PET at ≥ 0.2 ng/mL (≥ 1.0 ng/mL: 16.3%, ≥ 2.0 ng/mL: 2.3%, regardless of PSA: 11.7%). In case of PET-positive local recurrence (LR) and pelvic lymph nodes (LNs), 97.7% and 96.5% of the participants will apply an escalated dose. The median total dose in EQD2(1.5 Gy) was 70.00 Gy (range: 56.89–85.71) for LR and 62.00 Gy (range: 52.61–80.00) for LNs. A total number of ≤ 3 (22.0%) or ≤ 5 (20.2%) distant lesions was most often described as applicable for the definition as oligometastatic PC.

Conclusion

PSMA-PET is widely used among German radiation oncologists. However, specific implications on treatment planning differ among physicians. Therefore, further trials and guidelines for PET-based RT are warranted.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13014-021-01811-8.

Radiotherapy in nodal oligorecurrent prostate cancer

Objective

The current article encompasses a literature review and recommendations for radiotherapy in nodal oligorecurrent prostate cancer.

Materials and methods

A literature review focused on studies comparing metastasis-directed stereotactic ablative radiotherapy (SABR) vs. external elective nodal radiotherapy (ENRT) and studies analyzing recurrence patterns after local nodal treatment was performed. The DEGRO Prostate Cancer Expert Panel discussed the results and developed treatment recommendations.

Results

Metastasis-directed radiotherapy results in high local control (often > 90% within a follow-up of 1–2 years) and can be used to improve progression-free survival or defer androgen deprivation therapy (ADT) according to prospective randomized phase II data. Distant progression after involved-node SABR only occurs within a few months in the majority of patients. ENRT improves metastases-free survival rates with increased toxicity in comparison to SABR according to retrospective comparative studies. The majority of nodal recurrences after initial local treatment of pelvic nodal metastasis are detected within the true pelvis and common iliac vessels.

Conclusion

ENRT with or without a boost should be preferred to SABR in pelvic nodal recurrences. In oligometastatic prostate cancer with distant (extrapelvic) nodal recurrences, SABR alone can be performed in selected cases. Application of additional systemic treatments should be based on current guidelines, with ADT as first-line treatment for hormone-sensitive prostate cancer. Only in carefully selected patients can radiotherapy be initially used without additional ADT outside of the current standard recommendations. Results of (randomized) prospective studies are needed for definitive recommendations.

A Single-Institution Experience in Percutaneous Image-Guided Cryoablation of Lymph Node Metastases

OBJECTIVE. The purpose of this study was to assess the feasibility, safety, and efficacy of percutaneous cryoablation for the treatment of lymph node metastases. MATERIALS AND METHODS. In this single-institution retrospective study 55 patients were identified who underwent CT-guided cryoablation of metastatic lymph nodes between November 2006 and September 2019. Patient demographics, disease characteristics, and procedural details were recorded. The primary endpoints were technical success and major complications. The secondary endpoints were time to local and time to distant progression. Complications were graded according to the Society of Interventional Radiology consensus guidelines. RESULTS. The study sample comprised 55 patients (42 men, 13 women; mean age 64 ± 12 years) who underwent 61 cryoablation procedures to treat 65 lymph node metastases. Targeted nodes measured 1.7 ± 1.2 cm in mean short-axis diameter. Technical success was achieved in 60 of 61 cryoablation procedures (98%). Adjunctive maneuvers performed to protect adjacent structures included hydrodissection (n = 40), ureteral stenting (n = 3), and neural monitoring (n = 3). There were two Society of Interventional Radiology major complications (3%): pneumothorax (n = 1) and bleeding (n = 1). Local tumor control was achieved in treatment of 53 of 65 (82%) nodal metastases within a median of 25 months (range, 1-121 months) of follow-up. Local progression occurred in 12 of 65 cases (18%); the median time to recurrence was 11 months. CONCLUSION. Percutaneous cryoablation of nodal metastases is feasible and safe. Further investigation is warranted to assess the long-term efficacy of this technique and to define its role in oncologic care.

Long-term Clinical Outcomes of Repeat Salvage Lymph Node Dissection for Nodal Recurrence of Prostate Cancer After Radical Prostatectomy: A Case Series

This case series highlights the role of repeat salvage lymph node dissection (sLND) for nodal-recurrent prostate cancer. We provide a descriptive analysis of ten patients who underwent sLND in a total of 23 surgeries (mean 2.3 sLNDs per patient) and their long-term follow-up (median of 158 mo after radical prostatectomy). A complete prostate-specific antigen response was observed in nine/23 cases (39.1%), and an incomplete response in 14 (60.9%). Analysis by anatomical location revealed a trend towards more distant metastases on repeat surgery, with only three in-field recurrences in patients with previously positive nodes. Repeat sLND can be surgically challenging, and major intraoperative complications were observed in three/23 cases (13.0%). Repeat sLND for patients with nodal-recurrent prostate cancer seems to be a feasible treatment option, albeit only in carefully selected patients. Nevertheless, it remains a highly experimental approach with unclear oncological benefit.

Radiotherapy of oligometastatic prostate cancer: a systematic review

BACKGROUND

Due to improved imaging sensitivity, the term "oligometastatic" prostate cancer disease is diagnosed more often, leading to an increasing interest in metastasis-directed therapy (MDT). There are two types of radiation based MDT applied when treating oligometastatic disease: (1) stereotactic body radiation therapy (SBRT) generally used for bone metastases; or (2) SBRT for isolated nodal oligometastases combined with prophylactic elective nodal radiotherapy. This review aims to summarize current evidence data, which may shed light on the optimal management of this heterogeneous group of patients.

METHODS

A systematic review of the Medline database through PubMed was performed according to PRISMA guidelines. All relevant studies published up to November 2020 were identified and screened. Fifty-six titles were included. Besides outcome parameters, different prognostic and predictive factors were assessed, including site of metastases, time between primary treatment and MDT, use of systemic therapies, hormone sensitivity, as well as pattern of recurrence.

FINDINGS

Evidence consists largely of retrospective case series and no consistent precise definition of oligometastasis exists, however, most investigators seem to acknowledge the need to distinguish between patients presenting with what is frequently called "synchronous" versus "metachronous" oligometastatic disease. Available data on radiotherapy as MDT demonstrate high local control rates and a small but relevant proportion of patients without progressive disease after 2 years. This holds true for both hormone sensitive and castration resistant prostate cancer diseases. The use of 68Ga-PSMA PET/CT for staging increased dramatically. Radiation doses and field sizes varied considerably among the studies. The search for relevant prognostic and predictive factors is ongoing.

CONCLUSIONS

To our best knowledge this review on oligometastatic prostate cancer included the largest number of original articles. It demonstrates the therapeutic potential and challenges of MDT for oligometastatic prostate cancer. Prospective studies are under way and will provide further high-level evidence.

Positron Emission Tomography and Whole-body Magnetic Resonance Imaging for Metastasis-directed Therapy in Hormone-sensitive Oligometastatic Prostate Cancer After Primary Radical Treatment: A Systematic Review

CONTEXT

Next-generation imaging includes positron emission tomography (PET) imaging and whole-body magnetic resonance imaging (wbMRI) including diffusion-weighted imaging. Accurate quantification of oligometastatic disease using next-generation imaging is important to define the role and value of metastasis-directed therapy (MDT).

OBJECTIVE

To perform a review of next-generation imaging modalities in the detection of recurrent oligometastatic hormone-sensitive prostate cancer in men who received prior radical treatment for localized disease.

EVIDENCE ACQUISITION

MEDLINE, Scopus, Cochrane Libraries, and Web of Science databases were systematically searched for studies reporting next-generation imaging and oncological outcomes. An expert panel of urologists, radiation oncologists, radiologists, and nuclear medicine physicians performed a nonsystematic review of strengths and limitations of currently available imaging options for detecting the presence and extent of recurrent oligometastatic disease.

EVIDENCE SYNTHESIS

From 370 articles identified, three clinical trials and 21 observational studies met the following inclusion criteria: metachronous oligometastatic recurrence after radical treatment for prostate cancer, MDT, and hormone-sensitive patients. Androgen deprivation therapy (ADT) was allowed before MDT. Next-generation imaging modalities included PET/computed tomography and/or PET/MRI with the following tracers: choline (n = 1), NaF (n = 1), and prostate-specific membrane antigen (PSMA; n = 1) for clinical trials; choline (n = 7) or PSMA (n = 11) or both (n = 3) for observational studies. The number of metastases ranged from two to five lesions in most studies. In PSMA-based studies, progression-free survival ranged from 19% to 100%, whereas in studies employing choline, progression-free survival ranged from 16% to 93%. Overall, ADT-free survival ranged from 48% to 79%, while local control was reported as 75-100% and prostate-specific antigen response as 23-94%. Among the different PET tracers and wbMRI, PSMA PET is emerging as the most accurate imaging technique in defining the oligometastatic status.

CONCLUSIONS

PSMA and choline PET contribute to guiding MDT in men with hormone-sensitive oligometastatic prostate cancer. Further studies are warranted to ascertain their role and optimize the timing of imaging for such patients.

PATIENT SUMMARY

We looked at the evidence regarding the use of modern imaging techniques to direct additional treatments in men with early spread of prostate cancer after they receive their initial radical treatment. We found that next-generation imaging, in particular prostate-specific membrane antigen and choline positron emission tomography, can successfully guide metastasis-directed therapies, and further trials should evaluate which modalities are best suited to improve outcomes for our patients.

Prostate-specific membrane antigen targeted PET/CT for recurrent prostate cancer: a clinician's guide

INTRODUCTION

PSMA-targeted PET/CT is a 'Next Generation Imaging' technique with superior sensitivity and specificity for detecting recurrent prostate cancer compared with conventional imaging, allowing more accurate staging and re-staging.

AREAS COVERED

This article reviews the role of PSMA-targeted PET/CT in clinical management of men with recurrent prostate cancer.

EXPERT OPINION

Through enhanced spatial characterization of recurrent prostate cancer, PSMA-targeted PET/CT has shown significant impact on management decisions. In particular, by identifying men with recurrence confined to the prostate or pelvic nodes, PSMA-targeted PET/CT enables selective deployment of localized salvage therapies for management of biochemical failure after primary treatment with prostatectomy or radiotherapy. In oligometastatic disease, PSMA-targeted PET/CT may improve patient selection and treatment accuracy for metastasis-directed therapy and early phase II studies show encouraging results in delaying the need for systemic therapy. Further, quantitative PSMA-targeted PET/CT for monitoring response and therapeutic PSMA-targeted radiopharmaceuticals are emerging as encouraging treatment options in the setting of castrate-resistant disease.

Benefits of local consolidative treatment in oligometastases of solid cancers: a stepwise-hierarchical pooled analysis and systematic review

We conducted a meta-analysis of articles published in PubMed, MEDLINE, EMBASE, and Cochrane library to investigate the effectiveness of local consolidative therapy (LCT) against oligometastases. Data from randomized controlled trials (RCTs), balanced studies, and all studies combined were analyzed in a hierarchical manner. Pooled analyses of 31 studies (including seven randomized trials) investigating the effectiveness of LCT on overall survival revealed odds ratios of 3.04, 2.56, and 1.41 for all studies, balanced studies, and RCTs, respectively (all p < 0.05). The benefit of LCT was more prominent in patients with non-small cell lung and colorectal cancers than in those with prostate and small cell lung cancers. Moreover, the benefit of LCT was smaller in patients with high metastatic burdens (p = 0.054). In four of 12 studies with available information, additional grade ≥3 toxicities due to LCTs were reported. Overall, LCT is beneficial for patients with oligometastases, although such benefits are less evident in RCTs than in observational studies. Appropriate LCTs should be carefully selected considering their feasibility, disease type, and metastatic burden.

Oligorecurrent prostate cancer treated with metastases-directed therapy or standard of care: a single-center experience

BACKGROUND

The optimal treatment for oligorecurrent prostate cancer (PCa) is a matter of debate. We aimed to assess oncologic outcomes of patients treated with metastasis-directed therapy (MDT) vs. androgen deprivation therapy (ADT) for oligorecurrent PCa.

METHODS

We analyzed data from patients with oligorecurrent PCa treated with ADT (n = 121), salvage lymph node dissection (sLND) (n = 191) or external beam RT (EBRT) (n = 178). Radiological recurrence (RAR) was defined as a positive positron emission tomography imaging after MDT or ADT. Second-line systemic therapies (SST) were defined as any systemic therapy administered for progression. Oncologic outcomes were evaluated separately for patients with node-only or bone metastases. Kaplan-Meier method was used to assess time to RAR, SST, and cancer-specific mortality (CSM). Predictors of RAR, SST, and castration-resistant PCa (CRPCa) were assessed with Cox regression analyses.

RESULTS

Overall, 74 (22.6%), 63 (19.2%), and 191 (58.2%) patients were treated with ADT, EBRT, and sLND for lymph node-only recurrence. Both sLND (HR 0.56, 95% CI 0.33-0.94) and EBRT (HR 0.46, 95% CI 0.25-0.85) were associated with better RAR than ADT. Similarly, sLND (HR 0.25, 95% CI 0.13-0.50) and EBRT (HR 0.41, 95% CI 0.19-0.87) were associated with longer SST, as compared with ADT. Similar results were found for CRPCa status. Oncologic outcomes were similar between sLND and EBRT. MDT was not associated with survival benefit in patients with bone metastases as compared with ADT.

CONCLUSIONS

sLND and EBRT were associated with better RAR, SST, and CRPCa-free survival as compared with ADT in patients with oligometastatic PCa nodal recurrence. No difference in survival outcomes was observed between sLND and EBRT. MDT was not associated with survival benefit in patients with bone metastases, as compared with ADT.

Radiotherapy treatment volumes for oligorecurrent nodal prostate cancer: a systematic review

BACKGROUND

Radiotherapy is an emerging treatment strategy for nodal oligorecurrent prostate cancer (PCa) patients. However, large heterogeneities exist in the RT regimens used, with series reporting the use of elective nodal radiotherapy (ENRT) strategies and others the delivery of focal treatments to the relapsing nodes with Stereotactic Body Radiotherapy (SBRT). In this systematic review of the literature we compared the oncological outcomes and toxicity of the different RT regimens for nodal oligorecurrent PCa patients, with the aim of defining the optimal RT target volume in this setting.

METHODS

We performed a systemic search on the Pubmed database to identify articles reporting on the use of ENRT or SBRT for oligometastatic PCa with nodal recurrence.

RESULTS

Twenty-two articles were analyzed, including four prospective phase II trials (3 with SBRT and 1 with ENRT). Focal SBRT, delivered with an involved node, involved site, and involved field modality, was the most commonly used strategy with 2-year progression-free survival (PFS) rates ranging from 16 to 58% and a very low toxicity profile. Improved PFS rates were observed with ENRT strategies (52-80% at 3 years) compared to focal SBRT, despite a slightly higher toxicity rate. One ongoing randomized phase II trial is comparing both modalities in patients with nodal oligorecurrent PCa.

CONCLUSIONS

With a large variability in patterns of practice, the optimal RT strategy remains to be determined in the setting of nodal oligorecurrent PCa. Ongoing randomized trials and advances in translational research will help to shed light on the best management for these patients. .

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.

Clinical application of Fluciclovine PET, choline PET and gastrin-releasing polypeptide receptor (bombesin) targeting PET in prostate cancer

PURPOSE OF REVIEW

The aim of this review is to explore the clinical application of different PET radiopharmaceuticals in prostate cancer (PCa), beyond inhibitors of the prostate-specific membrane antigen (PSMA).

RECENT FINDINGS

Choline PET represented in the last decades the standard of reference for PET imaging in PCa and has been recently included in clinical trials evaluating the efficacy of metastasis-directed therapy in oligo-metastatic disease. Fluciclovine, as synthetic amino acid, has been proposed for investigating PCa. The results obtained by the first prospective studies led to FDA approval in 2016 in patients with biochemical recurrence. Recently, phase II/III trials explored its accuracy compared with PSMA PET and its impact on patient management. Imaging the gastrin-releasing polypeptide receptor (GRPR) recently drawn attention. Radio-labelled GRPR antagonists have the potential to be used as theranostic agents. Further evaluation is needed to understand the relation between GRPR expression and hormonal-resistant PCa, and for tumors characterized by heterogeneity of receptors expressed (e.g. PSMA-negative) on their cell surface.

SUMMARY

Other new generation PET tracers may play an important role in PCa, namely in case of PSMA-negative phenotypes.

Long-term Outcomes of Salvage Lymph Node Dissection for Nodal Recurrence of Prostate Cancer After Radical Prostatectomy: Not as Good as Previously Thought

BACKGROUND

Long-term outcomes of patients treated with salvage lymph node dissection (sLND) for nodal recurrence of prostate cancer (PCa) remain unknown.

OBJECTIVE

To investigate long-term oncological outcomes after sLND in a large multi-institutional series.

DESIGN, SETTING, AND PARTICIPANTS

The study included 189 patients who experienced prostate-specific antigen (PSA) rise and nodal-only recurrence after radical prostatectomy (RP) and underwent sLND at 11 tertiary referral centers between 2002 and 2011. Lymph node recurrence was documented by positron emission tomography/computed tomography (PET/CT) scan using either ¹¹C-choline or ⁶⁸Ga prostate-specific membrane antigen ligand.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

The primary outcome of the study was cancer-specific mortality (CSM). The secondary outcomes were overall mortality, clinical recurrence (CR), biochemical recurrence (BCR), and androgen deprivation therapy (ADT)-free survival after sLND. The probability of freedom from each outcome was calculated using Kaplan-Meier analyses. Cox regression analysis was used to predict the risk of prostate CSM after accounting for several parameters, including the use of additional treatments after sLND.

RESULTS AND LIMITATIONS

At long term, 110 and 163 patients experienced CR and BCR, respectively, with CR-free and BCR-free survival at 10 yr of 31% and 11%, respectively. After sLND, a total of 145 patients received ADT, with a median time to ADT of 41 mo. At a median (interquartile range) follow-up for survivors of 87 (51, 104) mo, 48 patients died. Of them, 45 died from PCa. The probabilities of freedom from cancer-specific and all-cause death at 10 yr were 66% and 64%, respectively. Similar results were obtained in sensitivity analyses in patients with pelvic-only positive PET/CT scan, as well as after excluding men on ADT at PET/CT scan and patients with PSA level at sLND higher than the 75th percentile. At multivariable analyses, patients who had PSA response after sLND (hazard ratio [HR]: 0.45; p = 0.001), and those receiving ADT within 6 mo from sLND (HR: 0.51; p = 0.010) had lower risk of death from PCa.

CONCLUSIONS

A third of men treated with sLND for PET-detected nodal recurrence of PCa died at long term, with PCa being the main cause of death. Salvage LND alone was associated with durable long-term outcomes in a minority of men who significantly benefited from additional treatments after surgery. Taken together, all these data argue against the use of metastasis-directed therapy alone for patients with node-only recurrent PCa. These men should instead be considered at high risk of systemic dissemination already at the time of sLND.

PATIENT SUMMARY

We assessed long-term outcomes of patients treated with salvage lymph node dissection (sLND) for node-recurrent prostate cancer (PCa). In contrast with prior evidence, we found that the majority of these men recurred after sLND and eventually died from PCa. A significant survival benefit associated with the administration of androgen deprivation therapy after sLND suggests that sLND should be considered part of a multimodal approach rather than an exclusive treatment strategy.

[18F]DCFPyL PET-MRI/CT for unveiling a molecularly defined oligorecurrent prostate cancer state amenable for curative-intent ablative therapy: study protocol for a phase II trial

INTRODUCTION

The oligometastatic (OM) disease hypothesis of an intermediate metastatic state with limited distant disease deposits amenable for curative therapies remains debatable. Over a third of prostate cancer (PCa) patients treated with radical prostatectomy and postoperative radiotherapy experience disease recurrence; these patients are considered incurable by current standards. Often the recurrence cannot be localised by conventional imaging (CT and bone scan). Combined anatomical imaging with CT and/or MR with positron emission tomography (PET) using a novel second-generation prostate-specific membrane antigen (PSMA) probe, [¹⁸F]DCFPyL, is a promising imaging modality to unveil disease deposits in these patients. A new and earlier molecularly defined oligorecurrent (OR) state may be amenable to focal-targeted ablative curative-intent therapies, such as stereotactic ablative radiotherapy (SABR) or surgery, thereby significantly delaying or completely avoiding the need for palliative therapies in men with recurrent PCa after maximal local treatments.

METHODS AND ANALYSIS

This ongoing single-institution phase II study will enrol up to 75 patients total, to include up to 37 patients with response-evaluable disease, who have rising prostate-specific antigen (range 0.4-3.0 ng/mL) following maximal local therapies with no evidence of disease on conventional imaging. These patients will undergo [¹⁸F]DCFPyL PET-MR/CT imaging to detect disease deposits, which will then be treated with SABR or surgery. The primary endpoints are performance of [¹⁸F]DCFPyL PET-MR/CT, and treatment response rates following SABR or surgery. Demographics and disease characteristics will be summarised and analysed descriptively. Response rates will be described with waterfall plots and proportions.

ETHICS AND DISSEMINATION

Ethics approval was obtained from the institutional Research Ethics Board. All patients will provide written informed consent. [¹⁸F]DCFPyL has approval from Health Canada. The results of the study will be disseminated by the principal investigator. Patients will not be identifiable as individuals in any publication or presentation of this study.

TRIAL REGISTRATION NUMBERS

NCT03160794.

PSMA-positive nodal recurrence in prostate cancer : Salvage radiotherapy is superior to salvage lymph node dissection in retrospective analysis

PURPOSE

This analysis compares salvage lymph node dissection (SLND) to salvage lymph node radiotherapy (SLNRT) of ⁶⁸Ga-PSMA PET-positive nodal recurrences after radical prostatectomy (RPE).

METHODS

A total of 67 SLNRT and 33 SLND consecutive patients with pelvic and/or para-aortic nodal recurrences after RPE were retrospectively analyzed. Biochemical recurrence-free survival rates (bRFS; PSA <0.2 ng/mL) were calculated according to Kaplan-Meier and survival curves were compared using the log rank test. For multivariable analysis, binary logistic regression analysis was performed (p < 0.05).

RESULTS

Median follow-up was 17 months (range, 6-53 months) in SLND patients and 31 months (range, 3-56 months) in SLNRT patients (p = 0.027). SLNRT patients had significantly more tumours of pT3 and pT4 category (82% vs. 67%; p = 0.006), pathologically involved lymph nodes (45% vs. 27%; p = 0.001) and positive surgical margins (54% vs. 12%; p = 0.001) at time of RPE than SLND patients. PSA persistence after RPE was significantly more frequently observed in the SLNRT cohort (73% vs. 27%; p = 0.001). There was no significant difference in the distribution of PET-positive lymph nodes. Median PSA before SLND was higher than before SLNRT (3.07 ng/ml vs. 1.3 ng/ml; p = 0.393). The 2‑year bRFS was significantly higher in the SLNRT vs. the SLND cohort (92% vs. 30%; p = 0.001) with lower rates of distant metastases (21% vs. 52%; p = 0.002) and secondary treatments (5% vs. 39%; p = 0.011) irrespective of ongoing androgen deprivation therapy at last contact. In multivariable analysis, SLNRT was significantly associated with prolonged bRFS (regression coefficient 1.436, hazard ratio 4.204, 95% CI 1.789-9.878; p = 0.001).

CONCLUSION

Based on this retrospective study SLNRT might be the preferred treatment option for patients with nodal recurrence after previous RPE.

Prognostic risk classification for biochemical relapse-free survival in patients with oligorecurrent prostate cancer after [68Ga]PSMA-PET-guided metastasis-directed therapy

PURPOSE

Since the success of prostate-specific membrane antigen-positron emission tomography (PSMA-PET) imaging for patients with oligorecurrent prostate cancer (ORPC), it is increasingly used for radiotherapy as metastasis-directed therapy (MDT). Therefore, we developed a prognostic risk classification for biochemical relapse-free survival (bRFS) for patients after PSMA-PET-guided MDT after radical prostatectomy.

METHODS

We analyzed 292 patients with local recurrence (LR) and/or pelvic lymph node (LN) lesions and/or up to five distant LN, bone (BM), or visceral metastases (VM) detected with [⁶⁸Ga]PSMA-PET imaging. Median follow-up was 16 months (range 0-57). The primary endpoint was bRFS after MDT. Cox regression analysis for risk factors was incorporated into a recursive partitioning analysis (RPA) with classification and regression tree method.

RESULTS

PSA at recurrence ≥ 0.8 ng/mL, BM, and VM was significantly associated with biochemical relapse. RPA showed five groups with tenfold cross-validation of 0.294 (SE 0.032). After building risk classes I to IV (p < 0.0001), mean bRFS was 36.3 months (95% CI 32.4-40.1) in class I (PSA < 0.8 ng/mL, no BM) and 25.8 months (95% CI 22.5-29.1) in class II (PSA ≥ 0.8 ng/mL, no BM, no VM). LR and/or pelvic LNs caused relapse in classes I and II. Mean bRFS was 16.0 months (95% CI 12.4-19.6) in class III (PSA irrelevant, present BM) and 5.7 months (95% CI 2.7-8.7) in class IV (PSA ≥ 0.8 ng/mL, no BM, present VM).

CONCLUSION

We developed and internally validated a risk classification for bRFS after PSMA-PET-guided MDT. Patients with PSA < 0.8 ng/mL and local relapse only (LR and/or pelvic LNs) had the most promising bRFS. PSA ≥ 0.8 ng/mL and local relapse only (LR and/or pelvic LNs) indicated intermediate risk for failure. Patients with BM were at higher risk regardless of the PSA. However, those patients still show satisfactory bRFS. In patients with VM, bRFS is heavily decreased. MDT in such cases should be discussed individually.

Influence of localization of PSMA-positive oligo-metastases on efficacy of metastasis-directed external-beam radiotherapy-a multicenter retrospective study

PURPOSE

Approximately 40-70% of biochemically persistent or recurrent prostate cancer (PCa) patients after radical prostatectomy (RPE) are oligo-metastatic in ⁶⁸gallium-prostate-specific membrane antigen positron emission tomography (⁶⁸Ga-PSMA PET). Those lesions are frequently located outside the prostate bed, and therefore not cured by the current standards of care like external-beam radiotherapy (EBRT) of the prostatic fossa. This retrospective study analyzes the influence of oligo-metastases' site on outcome after metastasis-directed radiotherapy (MDR).

METHODS

Retrospectively, 359 patients with PET-positive PCa recurrences after RPE were analyzed. Biochemical recurrence-free survival (BRFS) (prostate-specific antigen (PSA) < post-radiotherapy nadir + 0.2 ng/mL) was assessed using Kaplan-Meier survival and Cox regression analysis.

RESULTS

All patients were initially clinically without distant metastases (cM0). Seventy-five patients had local recurrence within the prostatic fossa, 32 patients had pelvic nodal plus local recurrence, 117 patients had pelvic nodal recurrence, 51 patients had paraaortic lymph node metastases with/without locoregional recurrence, and 84 patients had bone or visceral metastases with/without locoregional recurrence. Median PSA before MDR was 1.2 ng/mL (range, 0.04-47.5). Additive androgen deprivation therapy (ADT) was given in 35% (125/359) of patients. Median PSA nadir after MDR was 0.23 ng/mL (range, < 0.03-18.30). After a median follow-up of 16 months (1-57), 239/351 (68%) patients had no biochemical recurrence. Patients with distant lymph node and/or distant metastases, the so-called oligo-body cohort, had an overall in-field control of 90/98 (91%) but at the same time, an ex-field progress of 44/96 (46%). In comparison, an ex-field progress was detected in 28/154 (18%) patients with local and/or pelvic nodal recurrence (oligo-pelvis group). Compared with the oligo-pelvis group, there was a significantly lower BRFS in oligo-body patients at the last follow-up.

CONCLUSION

Overall, BRFS was dependent on patterns of metastatic disease. Thus, MDR of PSMA PET-positive oligo-metastases can be offered considering that about one-third of the patients progressed within a median follow-up of 16 months.