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

Five-year outcomes of fractionated stereotactic body radiotherapy for oligometastatic prostate cancer from the TRANSFORM phase II trial

Metastasis-directed therapy (MDT) for oligometastatic prostate cancer (PCa), including stereotactic body radiotherapy (SBRT), has shown promise but is still considered investigational. This is the 5-year analysis of the TRANSFORM trial, the largest prospective cohort of men with oligometastatic PCa treated with SBRT-based MDT. The primary endpoint was 5-year treatment escalation-free survival (TE-FS), defined as freedom from any new cancer therapy other than further SBRT. In total, 199 men received SBRT; 76.4% were hormone-naïve at baseline. The rate of 5-year TE-FS was 21.7% (95% confidence interval [CI]: 15.7%-28.7%) overall and 25.4% (95% CI: 18.1%-33.9%) in the hormone-naïve subgroup. The subgroups with International Society of Urological Pathology Grade Groups 4-5 disease (hazard ratio [HR] = 1.48, 95% CI: 1.05-2.01, p = .026), a higher baseline prostate-specific antigen (PSA) (HR = 1.06, 95% CI: 1.03-1.09, p < .001) and those who received prior androgen deprivation therapy (ADT) (HR = 2.13, 95% CI: 1.40-3.26, p < .001), were at greater risk of treatment escalation. Outcomes for participants with four or five initial lesions were comparable to those with one to three lesions. At last follow-up, 18.9% (95% CI: 13.2%-25.7%) of participants were free from treatment escalation (median follow-up of 67.9 months) and two participants had an undetectable PSA level. No treatment-related grade three or higher adverse events were reported. The findings of this study demonstrate that SBRT-based MDT is an effective option for delaying systemic treatment escalation in the context of oligometastatic PCa. Future randomised trials comparing SBRT-based MDT to standard-of-care ADT-based approaches are required to evaluate the impact of delaying ADT on survival.

EAU-EANM-ESTRO-ESUR-ISUP-SIOG Guidelines on Prostate Cancer. Part II-2024 Update: Treatment of Relapsing and Metastatic Prostate Cancer

BACKGROUND AND OBJECTIVE

The European Association of Urology (EAU)-European Association of Nuclear Medicine (EANM)-European Society for Radiotherapy and Oncology (ESTRO)-European Society of Urogenital Radiology (ESUR)-International Society of Urological Pathology (ISUP)-International Society of Geriatric Oncology (SIOG) guidelines on the treatment of relapsing, metastatic, and castration-resistant prostate cancer (PCa) have been updated. Here we provide a summary of the 2024 guidelines.

METHODS

The panel performed a literature review of new data, covering the time frame between 2020 and 2023. The guidelines were updated and a strength rating for each recommendation was added on the basis of a systematic review of the evidence.

KEY FINDINGS AND LIMITATIONS

Risk stratification for relapsing PCa after primary therapy may guide salvage therapy decisions. New treatment options, such as androgen receptor-targeted agents (ARTAs), ARTA + chemotherapy combinations, PARP inhibitors and their combinations, and prostate-specific membrane antigen-based therapy have become available for men with metastatic PCa.

CONCLUSIONS AND CLINICAL IMPLICATIONS

Evidence for relapsing, metastatic, and castration-resistant PCa is evolving rapidly. These guidelines reflect the multidisciplinary nature of PCa management. The full version is available online (http://uroweb.org/guideline/ prostate-cancer/).

PATIENT SUMMARY

This article summarises the 2024 guidelines for the treatment of relapsing, metastatic, and castration-resistant prostate cancer. These guidelines are based on evidence and guide doctors in discussing treatment decisions with their patients. The guidelines are updated every year.

Epidemiology, treatment patterns, and clinical outcomes in de novo oligometastatic hormone-sensitive prostate cancer

BACKGROUND

This study was conducted to better characterize the epidemiology, clinical outcomes, and current treatment patterns of de novo oligometastatic hormone-sensitive prostate cancer (omHSPC) in the United States Veterans Affairs Health Care System.

METHODS

In this observational retrospective cohort study, 400 de novo metastatic hormone-sensitive PC (mHSPC) patients diagnosed from January 2015 to December 2020 (follow-up through December 2021) were randomly selected. omHSPC was defined as five or less total metastases (excluding liver) by conventional imaging. Kaplan-Meier methods estimated overall survival (OS) and castration-resistant prostate cancer (CRPC)-free survival from mHSPC diagnosis date and a log-rank test compared these outcomes by oligometastatic status.

RESULTS

Twenty percent (79 of 400) of de novo mHSPC patients were oligometastatic. Most baseline characteristics were similar by oligometastatic status; however, men with non-omHSPC had higher median prostate-specific antigen at diagnosis (151.7) than omHSPC (44.1). First-line (1L) novel hormonal therapy was similar between groups (20%); 1L chemotherapy was lower in omHSPC (5%) versus non-omHSPC (14%). More omHSPC patients received metastasis-directed therapy/prostate radiation therapy (14%) versus non-omHSPC (2%). Median OS and CRPC-free survival (in months) were higher in omHSPC versus non-omHSPC (44.4; 95% confidence interval [CI], 33.9-not estimated vs. 26.2; 95% CI, 20.5-32.5, p = .0089 and 27.6; 95% CI, 22.1-37.2 vs. 15.3; 95% CI, 12.8-17.9, p = .0049), respectively.

CONCLUSIONS

Approximately 20% of de novo mHSPC were oligometastatic, and OS was significantly longer in omHSPC versus non-omHSPC. Although potentially "curative" therapy use was higher in omHSPC versus non-omHSPC, the percentages were still relatively low. Future studies are warranted given potential for prolonged responses with multimodal therapy inclusive of systemic and local therapies.

Assessment of treatment outcomes: cytoreductive surgery compared to radiotherapy in oligometastatic prostate cancer - an in-depth quantitative evaluation and retrospective cohort analysis

BACKGROUND

The management of oligometastatic prostate cancer, defined by its few metastatic sites, poses distinct clinical dilemmas. Debates persist regarding the most effective treatment approach, with both cytoreductive surgery and radiotherapy being key contenders. The purpose of this research is to thoroughly evaluate and compare the effectiveness of these two treatments in managing patients with oligometastatic prostate cancer.

METHODS

A comprehensive search of the literature was carried out to find pertinent publications that compared the results of radiation and cytoreductive surgery for oligometastatic prostate cancer. A meta-analysis was conducted in order to evaluate both short-term and long-term survival. Furthermore, utilizing institutional patient data, a retrospective cohort research was conducted to offer practical insights into the relative performances of the two treatment regimens.

RESULTS

Five relevant studies' worth of data were included for this meta-analysis, which included 1425 patients with oligometastatic prostate cancer. The outcomes showed that, in comparison to radiation, cytoreductive surgery was linked to a substantially better cancer-specific survival (CSS) [hazard ratio (HR): 0.70, 95% (CI): 0.59-0.81, P <0.001] and overall survival (OS) [HR, 0.80; 95% (CI), 0.77-0.82; P <0.01]. The two therapy groups' Progression-Free Survival (PFS) and Castration-Resistant Prostate Cancer-Free Survival (CRPCFS), however, did not differ significantly (HR: 0.56, 95% CI: 0.17-1.06; HR: 0.67, 95% CI: 0.26-1.02, respectively). Out of the 102 patients who were recruited in the retrospective cohort research, 36 had cytoreductive surgery (CRP), 36 had radiation therapy (primary lesion), and 30 had radiation therapy (metastatic lesion). The follow-up time was 46.3 months (18.6-60.0) on average. The enhanced OS in the CRP group [OS interquartile range (IQR): 45-60 months] in comparison to the radiation group (OS IQR: 39.0-59.0 months and 25.8-55.0 months, respectively) was further supported by the cohort research. Furthermore, CRP had a better OS than both radiation (primary region) and radiotherapy (metastatic region), with the latter two therapeutic methods having similar OS.

CONCLUSION

This meta-analysis and retrospective research provide valuable insights into the comparative efficacy of cytoreductive surgery and radiotherapy for oligometastatic prostate cancer. While short-term survival (PFS, CRPCFS) was similar between the two groups, cytoreductive surgery exhibited superior CSS and OS. Adverse event rates were manageable in both modalities. These findings contribute to informed treatment decision-making for clinicians managing oligometastatic prostate cancer patients. Further prospective studies and randomized controlled trials are essential to corroborate these results and guide personalized therapeutic approaches for this distinct subset of patients.

Novel Therapeutic Targets on the Horizon: An Analysis of Clinical Trials on Therapies for Bone Metastasis in Prostate Cancer

In the absence of early detection and initial treatment, prostate cancer often progresses to an advanced stage, frequently spreading to the bones and significantly impacting patients' well-being and healthcare resources. Therefore, managing patients with prostate cancer that has spread to the bones often involves using bone-targeted medications like bisphosphonates and denosumab to enhance bone structure and minimize skeletal complications. Additionally, researchers are studying the tumor microenvironment and biomarkers to understand the mechanisms and potential treatment targets for bone metastases in prostate cancer. A literature search was conducted to identify clinical studies from 2013 to 2023 that focused on pain, performance status, or quality of life as primary outcomes. The analysis included details such as patient recruitment, prior palliative therapies, baseline characteristics, follow-up, and outcome reporting. The goal was to highlight the advancements and trends in bone metastasis research in prostate cancer over the past decade, with the aim of developing strategies to prevent and treat bone metastases and improve the quality of life and survival rates for prostate cancer patients.

Progress in Oligometastatic Prostate Cancer: Emerging Imaging Innovations and Therapeutic Approaches

Prostate cancer (PCa) exhibits a spectrum of heterogeneity, from indolent to highly aggressive forms, with approximately 10-20% of patients experiencing metastatic PCa. Oligometastatic PCa, characterized by a limited number of metastatic lesions in specific anatomical locations, has gained attention due to advanced imaging modalities. Although patients with metastatic PCa typically receive systemic therapy, personalized treatment approaches for oligometastatic PCa are emerging, including surgical and radiotherapeutic interventions. This comprehensive review explores the latest developments in the field of oligometastatic PCa, including its biological mechanisms, advanced imaging techniques, and relevant clinical studies. Oligometastatic PCa is distinct from widespread metastases and presents challenges in patient classification. Imaging plays a crucial role in identifying and characterizing oligometastatic lesions, with new techniques such as prostate-specific membrane antigen positron emission tomography demonstrating a remarkable efficacy. The management strategies encompass cytoreductive surgery, radiotherapy targeting the primary tumor, and metastasis-directed therapy for recurrent lesions. Ongoing clinical trials are evaluating the effectiveness of these approaches. Oligometastatic PCa occupies a unique position between locally advanced and high-volume metastatic diseases. While a universally accepted definition and standardized diagnostic criteria are still evolving, emerging imaging technologies and therapeutic strategies hold promise for improving the patient outcomes in this intermediate stage of PCa.

Predictors of Recurrence After Metastasis-directed Therapy in Oligorecurrent Prostate Cancer Following Radical Prostatectomy

BACKGROUND

Metastasis-directed therapy (MDT) is performed to delay systemic treatments for oligorecurrent disease after primary prostate cancer (PCa) treatment.

OBJECTIVE

The aim of this study was to identify the predictors of therapeutic response of MDT for oligorecurrent PCa.

DESIGN, SETTING, AND PARTICIPANTS

bicentric, retrospective study, including consecutive patients who underwent MDT for oligorecurrent PCa after radical prostatectomy (RP; 2006-2020) was conducted. MDT encompassed stereotactic body radiation therapy (SBRT), salvage lymph node dissection (sLND), whole-pelvis/retroperitoneal radiation therapy (WP[R]RT), or metastasectomy.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

ndpoints were 5-yr radiographic progression-free survival (rPFS), metastasis-free survival (MFS), palliative androgen deprivation treatment (pADT)-free survival, and overall survival (OS) together with prognostic factors for MFS following primary MDT. Survival outcomes were studied by Kaplan-Meier survival and univariable Cox regression (UVA).

RESULTS AND LIMITATIONS

A total of 211 MDT patients were included; 122 (58%) developed a secondary recurrence. Salvage lymph node dissection was performed in 119 (56%), SBRT in 48 (23%), and WP(R)RT in 31 (15%) of the cases. Two patients received sLND + SBRT and one received sLND + WPRT. Eleven (5%) patients received metastasectomies. The median follow-up since RP was 100 mo, while follow-up after MDT was 42 mo. The 5-yr rPFS, MFS, androgen deprivation treatment(-free survival, castration-resistant prostate cancer-free survival, CSS, and OS after MDT were 23%, 68%, 58%, 82%, 93%, and 87% respectively. There was a statistically significant difference between cN1 (n = 114) and cM+ (n = 97) for 5-yr MFS (83% vs 51%, p < 0.001), pADT-free survival (70% vs 49%, p = 0.014), and CSS (100% vs 86%, p = 0.019). UVA was performed to assess the risk factors (RFs) for MFS in cN1 and cM+. Alpha was set at 10%. RFs for MFS in cN1 were lower initial prostate-specific antigen (PSA) at the time of RP (hazard ratio [95% confidence interval] 0.15 [0.02-1.02], p = 0.053], pN stage at RP (2.91 [0.83-10.24], p = 0.096), nonpersisting PSA after RP (0.47 [0.19-1.12], p = 0.089), higher PSA at primary MDT (2.38 [1.07-5.24], p = 0.032), and number of positive nodes on imaging (1.65 [1.14-2.40], p < 0.01). RFs for MFS in cM+ were higher pathological Gleason score (1.86 [0.93-3.73], p = 0.078), number of lesions on imaging (0.77 [0.57-1.04], p = 0.083), and cM1b/cM1c (non-nodal metastatic recurrence; 2.62 [1.58-4.34], p < 0.001).

CONCLUSIONS

Following MDT, 23% of patients were free of a second recurrence at 5-yr follow-up. Moreover, cM+ patients had significantly worse outcomes in terms of MFS, pADT-free survival, and CSS. The RFs for a metastatic recurrence can be used for counseling patients, to inform prognosis, and potentially select candidates for MDT.

PATIENT SUMMARY

In this paper, we looked at the outcomes of using localized, patient-tailored treatment for imaging-detected recurrent prostate cancer in lymph nodes, bone, or viscera (maximum five recurrences on imaging). Our results showed that targeted treatment of the metastatic lesions could delay the premature use of hormone therapy.

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.

Management of bone metastasis in prostate cancer

Progression of bone metastases is the primary cause of death in prostate cancer, and skeletal-related events (SREs), including pathologic fractures, spinal cord compression, radiation, or surgery to bone can impair patients' quality of life. Over the past decade, the development of cytotoxic agents, androgen-receptor-axis-targeted therapies (ARATs), and radioligand therapies has prolonged overall survival of prostate cancer patients with bone metastases and reduced the risk of SREs. The use of bone-modifying agents has also contributed to the reduced risk of SREs. Initial use of a cytotoxic agent, docetaxel, or an ARAT agent with androgen deprivation therapy (ADT) is the current approach to metastatic castration-sensitive prostate cancer. However, there is no consensus on the optimal medication for upfront use in combination with ADT, or on specific patient selection. Recently, next-generation imaging modalities, such as whole-body magnetic resonance imaging and prostate-specific membrane antigen-positron emission tomography have been utilized to detect bone metastases at an early stage. In addition, metastasis-directed therapy, such as stereotactic body radiation therapy, has been attempted. In the future, patients with bone metastatic prostate cancer will be divided into subgroups and their treatment options will be tailored to their specific characteristics.

Outcome of patients with biochemical recurrence of prostate cancer after PSMA PET/CT-directed radiotherapy or surgery without systemic therapy

BACKGROUND

Radiotherapy (RT) and surgery are potential treatment options in patients with biochemical recurrence (BCR) following primary prostate cancer treatment. This study examines the value of prostate-specific membrane antigen (PSMA) positron emission tomography/computed tomography (PET/CT)-informed surgery and RT in patients with BCR treated without systemic therapy.

METHODS

This is a post-hoc subgroup analysis of a prospective clinical trial. Inclusion criteria were: histologically proven prostate cancer at initial curative-intent treatment, BCR after primary treatment with curative intent, having five or fewer lesions identified on [¹⁸F]DCFPyL PET/CT, and treatment with either PET/CT-directed RT or surgery without systemic therapy. The biochemical progression-free survival after PSMA ligand PET/CT-directed RT and surgery was determined. Uni- and multivariate Cox regression analyses were performed for the association of patients' characteristics, tumor-specific variables, and PSMA PET/CT imaging results with biochemical progression at the last follow-up.

RESULTS

Fifty-eight patients (30 in surgery and 28 in radiotherapy groups) met the inclusion criteria. A total of 87 PSMA-positive lesions were detected: 16 local recurrences (18.4%), 54 regional lymph nodes (62.1%), 6 distant lymph nodes (6,8%), and 11 osseous lesions (12.7%). A total of 85.7% (24 of 28) and 70.0% (21 of 30) of patients showed a ≥ 50% decrease in prostate-specific antigen (PSA) levels after RT and surgery, respectively. At a median follow-up time of 21 months (range, 6-32 months), the median biochemical progression-free survival was 19 months (range, 4 to 23 months) in the radiotherapy group, as compared with 16.5 months (range, 4 to 28 months) in the surgery group. On multivariate Cox regression analysis, the number of PSMA positive lesions (2-5 lesions compared to one lesion), and the anatomic location of the detected lesions (distant metastasis vs. local relapse and pelvic nodal relapse) significantly correlated with biochemical progression at the last follow-up, whereas other clinical, tumor-specific, and imaging parameters did not.

CONCLUSIONS

This study suggests that RT or surgery based on [¹⁸F]DCFPyL PET/CT are associated with high PSA response rates. The number and site of lesions detected on the PSMA PET/CT were predictive of biochemical progression on follow-up. Further studies are needed to assess the impact of targeting these sites on patient relevant outcomes.

TRIAL REGISTRATION

Registered September 14, 2016; NCT02899312; https://clinicaltrials.gov/ct2/show/NCT02899312.

Metastasectomy of a solitary liver tumor from prostate cancer after radical prostatectomy

Introduction

Metastasectomy of oligometastatic prostate cancer has the potential to contribute to improving prognosis. We report on a case of metastasectomy of solitary liver tumor after radical prostatectomy.

Case presentation

An 80-year-old man underwent radical prostatectomy for prostate cancer, followed by radiotherapy after the operation because of increased serum prostate-specific antigen levels of 0.529 ng/mL. Levels increased further to 0.997 ng/mL even after salvage therapy. The patient then received androgen deprivation therapy. Levels remained stable for 3 years, but rapidly increased to 19.781 ng/mL in the following 6 months. Abdominal computed tomography revealed a solitary liver tumor, and no metastasis to other sites was identified. The patient underwent liver segmentectomy. Microscopic examination of excised specimens revealed prostate cancer cells. Five years after surgery, serum prostate-specific antigen maintained to the lowest level so far.

Conclusion

Metastasectomy might be a beneficial therapeutic option to improve the prognosis for solitary metastasis from prostate cancer.

Defining the optimal template of salvage lymph node dissection for unilateral pelvic nodal recurrence of prostate cancer following radical prostatectomy

OBJECTIVES

Several retrospective studies have shown that salvage bilateral pelvic lymph node dissection (sLND) is a valid treatment option in the setting of oligorecurrent nodal prostate cancer following radical prostatectomy. Little is known about the optimal template of such sLND in patients with strictly unilateral pelvic recurrence on PET-CT imaging. In this study, we investigated whether a unilateral pelvic sLND could be sufficient in such a setting.

METHODS

We retrospectively collected data of patients treated with sLND between 2010 and 2019 at the University Hospitals, Leuven. Patients were included if they developed recurrence following radical prostatectomy, characterized by ≤3 unilateral pelvic lymph node metastases on Choline or PSMA PET-CT and received a super-extended bilateral pelvic sLND as first metastasis-directed therapy. As a primary endpoint, we investigated in how many cases a unilateral sLND would have been sufficient.

RESULTS

In total, 44 patients with strictly unilateral pelvic recurrence were treated with super-extended bilateral pelvic sLND. In 5 out of 44 (11%) patients, histological examination showed presence of prostate cancer in the contralateral hemi-pelvis. In the group with a single positive node on imaging prior to sLND, only 1 out of 27 (3%) patients had contralateral disease at final pathology. No one (0%) in this group subsequently developed recurrence in the contralateral hemi-pelvis following sLND.

CONCLUSIONS

In conclusion, this study suggests that unilateral pelvic sLND could be sufficient in patients with a single unilateral pelvic lymph node recurrence on PET/CT imaging.

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.

Management Impact of Metachronous Oligometastatic Disease Identified on 18F-Fluciclovine (Axumin™) PET/CT in Biochemically Recurrent Prostate Cancer

PURPOSE

We assessed the incidence rate and management impact of oligometastatic disease detected on ¹⁸F-fluciclovine (Axumin™) PET/CT in men with first biochemical recurrence (BCR) of prostate cancer (PCA) after definitive primary therapy.

METHODS AND MATERIALS

We retrospectively reviewed our clinical database for men with PCA who underwent ¹⁸F-fluciclovine PET/CT for imaging evaluation of BCR with negative or equivocal findings on conventional imaging. We included patients with up to and including 5 metastases (oligometastases) regardless of imaging evidence for local recurrence in the treated prostate bed. We examined the association between mean serum prostate specific antigen (PSA) levels with the number of oligometastases (non-parametric ANOVA) and between patients with or without local recurrence (Student t-test). The management impact of oligometastatic disease was tabulated.

RESULTS

We identified 21 patients with oligometastases upon first BCR (PSA 0.2-56.8 ng/mL) out of 89 eligible patients. There was a significant difference (p = 0.04) in the mean PSA levels between patients with local recurrence (n = 12) and those without local recurrence (n = 9). In the subgroup of analysis of patients without local recurrence, there was no significant association between mean PSA level and number of oligometastases (p = 0.83). Distribution of oligometastases included 66.7% isolated nodal disease and 33.3% bone only. Twelve (57.1%) patients had change in management to include change in ADT, salvage therapy, or both. Treatment change was initiated in 62.5%, 28.6%, 66.7%, 100%, and 100% of patients with 1, 2, 3, 4, and 5 oligometastatic lesions, respectively.

CONCLUSION

The incidence rate of oligometastatic disease in men with first BCR of PCA undergoing ¹⁸F-fluciclovine PET/CT for imaging evaluation of BCR was 23.6% in our eligible patient population. There was no significant association between serum PSA level and the number of oligometastases. Treatment management was affected in 57.1% of patients with oligometastases.

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.

Oligometastatic Prostate Cancer: Current Status and Future Challenges

In accordance with the spectrum theory of metastatic disease, an oligometastatic clinical state has been proposed as an intermediary step along the natural history of cancer with few (typically 1-3) metastatic lesions identifiable on imaging that may be amenable to metastasis-directed therapy. Effective therapy of oligometastatic disease is anticipated to impact cancer evolution by delaying progression and improving patient outcome at a minimal or acceptable cost of toxicity. There has been increasing recognition of oligometastatic disease in prostate cancer with the advent of new-generation imaging agents, most notably the recently approved PET radiotracers based on targeting prostate-specific membrane antigen. Early clinical trials with metastasis-directed therapy of oligometastases have provided evidence for delaying the employment of systematic therapy and improving outcome in selected patients. Despite these encouraging results, much needs to be investigated and learned about the underlying biology of the oligometastatic state along the evolutionary clinical course of prostate cancer, the identification of relevant imaging and nonimaging predictive and prognostic biomarkers, and the development of treatment strategies to optimize short-term and long-term patient outcome. We provide a review of the current status and the lingering challenges of this rapidly evolving clinical space in prostate cancer.

The Effect of MDT Collaborative Nursing Combined with Hierarchical Nursing Management Model on the Quality of Life and Comfort of Patients with Gallbladder Stones Combined with Acute Cholecystitis after Surgery

Objective

To explore the effect of MDT (multidisciplinary team) collaborative nursing combined with hierarchical nursing management mode on the quality of life and comfort of patients with gallbladder stones combined with acute cholecystitis after surgery.

Methods

A total of 120 patients with gallbladder stones and acute cholecystitis who were treated in our hospital from March 2019 to March 2021 were selected as prospective research objects. According to the order of care, they were divided into control group and observation group with 60 cases each. Among them, the control group implements a hierarchical nursing management model, and the observation group implements MDT collaborative nursing based on this and compares the impact of the two groups on patient's quality of life scores, daily self-care ability, nursing satisfaction, and comfort after nursing.

Results

Before nursing, the comparison of the quality of life score, nursing comfort, and nursing ability of the two groups of patients was not statistically significant (P > 0.05). After nursing, the mental vitality score, social interaction score, emotional restriction score, and mental status of the observation group were significantly higher than those of the control group. Statistics showed that the difference was statistically significant (P < 0.05). After nursing, the scores of social comfort, physical comfort, and psychological comfort of the observation group were significantly higher than those of the control group, and statistics showed that the difference was statistically significant (P < 0.05). The health knowledge level, self-care skills, self-care responsibility, and self-concept of the observation group after nursing were higher than those of the control group, while the score of depression and mood disorder was significantly lower than that of the control group. Statistics showed that this difference was statistically significant (P < 0.05). After nursing, patients in the observation group had higher operating technique scores, service attitude scores, health education scores, psychological intervention scores, and nursing quality scores than those of the control group. Statistics showed that the difference was statistically significant (P < 0.05).

Conclusion

MDT collaborative nursing combined with hierarchical nursing management mode can effectively improve the self-care ability of patients with gallbladder stones complicated with acute cholecystitis, effectively improve the quality of life of patients, and improve the satisfaction and comfort of patients with nursing care. The postnursing care of patients after inflammation has a certain reference value.

Radiotherapy for hormone-sensitive prostate cancer with synchronous low burden of distant metastases

Purpose

The DEGRO Expert Commission on Prostate Cancer has revised the indication for radiation therapy of the primary prostate tumor in patients with synchronous distant metastases with low metastatic burden.

Methods

The current literature in the PubMed database was reviewed regarding randomized evidence on radiotherapy of the primary prostate tumor with synchronous low metastatic burden.

Results

In total, two randomized trials were identified. The larger study, the STAMPEDE trial, demonstrated an absolute survival benefit of 8% after 3 years for patients with low metastatic burden treated with standard of care (SOC) and additional radiotherapy (RT) (EQD2 ≤ 72 Gy) of the primary tumor. Differences in the smaller Horrad trial were not statistically significant, although risk reduction in the subgroup (< 5 bone metastases) was equal to STAMPEDE. The STOPCAP meta-analysis of both trials demonstrated the benefit of local radiotherapy for up to 4 bone lesions and an additional subanalysis of STAMPEDE also substantiated this finding in cases with M1a-only metastases.

Conclusion

Therefore, due to the survival benefit after 3 years, current practice is changing. New palliative SOC is radiotherapy of the primary tumor in synchronously metastasized prostate cancer with low metastatic burden (defined as ≤ 4 bone metastases, with or without distant nodes) or in case of distant nodes only detected by conventional imaging.

Oligometastatic deposits of prostate cancer found within the sigmoid pericolic fat that was resected for colonic adenocarcinoma: a case report

BACKGROUND

Prostate cancer may rarely metastasize to the colon and colonic lymph nodes, and local treatment of oligometastatic deposits may improve oncological outcomes. Immunohistochemical stains are used to determine the most likely source of metastatic deposits when they are seen within surgical specimens. The aim of this case report is to illustrate how such techniques were used to identify unexpected prostatic metastases within the pericolic fat of a sigmoid colon resection specimen following elective curative surgery for colorectal cancer. To our knowledge, this is the first report of complete excision of oligometastatic deposits of prostate cancer found incidentally within the specimen of another cancer.

CASE REPORT

An 89-year-old Caucasian man underwent sigmoid colectomy for an obstructing colorectal cancer in the sigmoid colon with some mesenteric lymphadenopathy. He had previously received radical radiotherapy for prostate cancer 10 years earlier. When the specimen was examined by the histopathologist, it was noted that the pericolic fat adjacent to the colorectal adenocarcinoma contained some metastatic deposits. Positive immunohistochemical staining for prostate-specific antigen and prostate-specific acid phosphatase with negative staining for CDX2 and CK20 revealed these to be prostatic metastases rather than colonic. Since these were completely excised, and there were no other metastases, this represented a serendipitous, curative excision of oligometastatic deposits of an additional cancer to the one that was being treated.

CONCLUSIONS

This case illustrates how immunohistochemical staining may be used to distinguish the source of metastatic deposits based on the likelihood of primary tumor from a careful and thorough patient history.

Narrative review of local prostate and metastasis-directed radiotherapy in the treatment of metastatic prostate cancer

The role of local treatment in patients with de novo metastatic prostate cancer is controversial. In population-based retrospective studies, metastatic prostate cancer patients who received local treatment with prostate radiotherapy showed a better prognosis than those who did not. In addition, several prospective randomized studies demonstrated that prostate radiotherapy achieves a survival benefit for patients with oligo-metastasis. Moreover, the efficacy of metastasis-directed radiotherapy was evaluated, revealing a potential benefit for patients with oligo-metastasis. Importantly, these radiotherapies may reduce the occurrence of symptomatic local events. In this review, the rationale, efficacy and future perspectives for local prostate and metastasis-directed radiotherapy in the treatment of metastatic prostate cancer were described and summarized.

Epithelial cell adhesion molecule‑targeting designed ankyrin repeat protein‑toxin fusion Ec1‑LoPE exhibits potent cytotoxic action in prostate cancer cells

Targeted anticancer therapeutics offer the advantage of reducing cytotoxic side effects to normal cells by directing the cytotoxic payload selectively to cancer cells. Designed ankyrin repeat proteins (DARPins) are promising non-immunoglobulin-based scaffold proteins for payload delivery to cancer-associated molecular targets. Epithelial cell adhesion molecule (EpCAM) is overexpressed in 40–60% of prostate cancers (PCs) and is associated with metastasis, increased risk of PC recurrence and resistance to treatment. Here, we investigated the use of DARPin Ec1 for targeted delivery of Pseudomonas exotoxin A variant (LoPE) with low immunogenicity and low non-specific toxicity to EpCAM-expressing prostate cancer cells. Ec1-LoPE fusion protein was radiolabeled with tricarbonyl technetium-99m and its binding specificity, binding kinetics, cellular processing, internalization and cytotoxicity were evaluated in PC-3 and DU145 cell lines. Ec1-LoPE showed EpCAM-specific binding to EpCAM-expressing prostate cancer cells. Rapid internalization mediated potent cytotoxic effect with picomolar IC₅₀ values in both studied cell lines. Taken together, these data support further evaluation of Ec1-LoPE in a therapeutic setting in a prostate cancer model in vivo.

Stereotactic Body Radiotherapy for a Sacral Metastasis Clarified by Diffusion-Weighted Whole-Body Imaging With Background Body Signal Suppression in a Patient With Castration-Resistant Prostate Cancer

Diffusion-weighted whole-body imaging with background body signal suppression (DWIBS) is an emerging extended modality of diffusion-weighted imaging for screening malignant lesions in the body. A 70-year-old male was diagnosed with advanced-stage prostate adenocarcinoma with distant metastasis. After hormone therapy, the disease progressed to castration-resistant prostate cancer (CRPC). Serum prostate-specific antigen (PSA) levels increased during androgen deprivation therapy with low serum testosterone levels. 18F-Fluorodeoxyglucose positron emission tomography (FDG-PET) and technetium-99m methylene bone scintigraphy (BS) did not reveal obvious distant metastases; however, we were able to identify distant metastases by DWIBS. We herein report a case in which stereotactic body radiotherapy (SBRT) was performed on target lesions detected by DWIBS and successfully suppressed disease progression.

Repeated Multimodality Ablative Therapies for Oligorecurrent Pulmonary Metastatic Disease

Stereotactic body radiotherapy (SBRT) and percutaneous thermal ablation (TA) are alternatives to surgery for the management of pulmonary oligometastases. In this collaborative work, we retrospectively analyzed patients who had undergone iterative focal ablative treatments of pulmonary oligometastases. We hypothesized that repeated ablative therapies could benefit patients with consecutive oligometastatic relapses. Patients treated with SBRT and/or TA for pulmonary oligometastases in two French academic centers between October 2011 and November 2016 were included. A total of 102 patients with 198 lesions were included; 45 patients (44.1%) received repeated focal treatments at the pulmonary site for an oligorecurrent disease (the “multiple courses” group). Median follow-up was 22.5 months. The 3-year overall survival rates of patients who had a single treatment sequence (the “single course” group) versus the “multiple courses” were 73.9% and 78.8%, respectively, which was not a statistically significant difference (p = 0.860). The 3-year systemic therapy-free survival tended to be longer in the “multiple courses” group (50.4%) than in the “single course” group (44.7%) (p = 0.081). Tolerance of repeated treatments was excellent with only one grade 4 toxicity. Thereby, multimodality repeated ablative therapy is effective in patients with pulmonary oligorecurrent metastases. This strategy may delay the use of more toxic systemic therapy.

Efficacy and safety of bipolar androgen therapy in castration-resistant prostate cancer following abiraterone or enzalutamide resistance: A systematic review

Bipolar androgen therapy (BAT) is a new endocrinologic treatment for castration-resistant prostate cancer (CRPC) that can restore some patients' sensitivity to drugs such as abiraterone (Abi) and enzalutamide (Enz). We performed a meta-analysis using STATA16. Sensitivity analyses were performed by examining the effects of individual studies using different effect models and detecting any publication bias using the Harbord test. In a total of 108 unique records, ten studies were included in the final meta-analysis. Participants who underwent BAT achieved a PSA50 response rate of 27% (95%CI [0.22,0.31], I2=17.98%), ORR of 34% (95%CI [0.24,0.43], I2=0), and incidence of AEs (grade≥3) of 14% (95%CI [0.09,0.19], I2=0). Patients who completed BAT proceeded to AR-targeted therapy (Abi or Enz) and achieved a PSA50 response rate of 57% (95% CI [0.36,0.78], I2=0). Patients with prior Enz resistance had a stronger impact on the PSA50 of AR-target therapy rechallenge. The results of this meta-analysis indicate that BAT is a safe and effective treatment for patients who have progressed after Abi or Enz. BAT can trigger the resensitization of patients with CRPC to subsequent endocrine therapy and improve the overall survival of patients and their quality of life.

Toxicity and Efficacy of Local Ablative, Image-guided Radiotherapy in Gallium-68 Prostate-specific Membrane Antigen Targeted Positron Emission Tomography-staged, Castration-sensitive Oligometastatic Prostate Cancer: The OLI-P Phase 2 Clinical Trial

BACKGROUND

Local ablative radiotherapy (aRT) of oligometastatic prostate cancer (PCa) is very promising and has become a focus of current clinical research.

OBJECTIVE

We hypothesize that aRT is safe and effective in gallium-68 prostate-specific membrane antigen targeted positron emission tomography (PSMA-PET)-staged oligometastatic PCa patients.

DESIGN, SETTING, AND PARTICIPANTS

A nonrandomized, prospective, investigator-initiated phase 2 trial recruited patients with oligometastatic PCa (five or fewer lymph node or osseous metastases) after local curative therapy, without significant comorbidity and androgen deprivation therapy (ADT), at two German centers from 2014 to 2018.

INTERVENTION

All PSMA-PET-positive metastases were treated with aRT. No systemic therapy was initiated.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

The primary endpoint was treatment-related toxicity (grade ≥2) 24 mo after aRT. A one-sided single-sample test of proportions was planned to test whether the endpoint occurs in <15% of the patients. Key secondary endpoints were time to progression of prostate-specific antigen (PSA) and time to ADT, which were associated with potential prognostic factors by Cox regression.

RESULTS AND LIMITATIONS

Of 72 patients, 63 received aRT (13% dropout rate). The median follow-up was 37.2 mo. No treatment-related grade ≥2 toxicity was observed 2 yr after treatment. The median time to PSA progression and time to ADT were 13.2 and 20.6 mo, respectively. Of the patients, 21.4% were free of PSA progression after 3 yr.

CONCLUSIONS

It was observed that aRT is safe, and midterm PSA progression and ADT-free time were achieved in one of five patients. Randomized clinical trials are indicated to further evaluate the option of delaying ADT in selected patients.

PATIENT SUMMARY

In this clinical trial, 63 patients with up to five metastases of prostate cancer without androgen deprivation therapy were included. We showed that local ablative radiotherapy is safe and that one in five patients had no recurrent prostate-specific antigen value after 3 yr. Local ablative radiotherapy might be an option to avoid systemic therapy in selected patients.

Current usage of stereotactic body radiotherapy for oligometastatic prostate cancer in Korea: patterns of care survey (KROG 19-08)

Background

Growing evidence suggests that metastasis-directed therapy and/or prostate-directed therapy may benefit patients with oligometastatic prostate cancer (OMPC). Stereotactic body radiotherapy (SBRT) is increasingly used to treat oligometastases in various cancers. The purpose of this study was to investigate the current patterns of curative-intent SBRT for OMPC in Korea.

Methods

A 20-item questionnaire was sent to 326 radiation oncologists in 93 institutions in Korea. Only 1 physician per institution was required to complete the survey. Subsequently, the second survey consisting of 3 clinical scenarios was sent to 64 physicians with clinical experience in SBRT: case 1, cT4N0M1 (direct invasion to two pelvic bones); case 2, cT2N0M1 (three bone metastases); and case 3, solitary spine metastasis after radical prostatectomy.

Results

Seventy-six physicians from 93 institutions (82%) answered the first survey. The multidisciplinary team approach was practiced in 16 institutions (21%). Most physicians (75%) agreed on the definition of oligometastases as limited lesions and/or organs ≤5: 25% agreed with low-volume disease according to CHAARTED trial. During the last year, 49 physicians (64%) treated OMPC patients with curative intent. Sixty four physicians (84%) had a clinical experience with SBRT: 48 (75%) stated that both dose and fraction number should be considered when defining SBRT, whereas others (25%) stated that only fraction size should be considered. Fifty-five faculties (86%) answered the second survey. Physicians agreed with oligometastases in 89% for case 1, in 80% for case 2, and in 100% for case 3. The rate of SBRT application was the highest in case 3 (70%).

Conclusions

There was diversity in the patterns of SBRT for OMPC in Korea. Additional prospective studies are necessary to strengthen evidence regarding role of SBRT in OMPC.

Prostate cancer

The management of prostate cancer continues to evolve rapidly, with substantial advances being made in understanding the genomic landscape and biology underpinning both primary and metastatic prostate cancer. Similarly, the emergence of more sensitive imaging methods has improved diagnostic and staging accuracy and refined surveillance strategies. These advances have introduced personalised therapeutics to clinical practice, with treatments targeting genomic alterations in DNA repair pathways now clinically validated. An important shift in the therapeutic framework for metastatic disease has taken place, with metastatic-directed therapies being evaluated for oligometastatic disease, aggressive management of the primary lesion shown to benefit patients with low-volume metastatic disease, and with several novel androgen pathway inhibitors significantly improving survival when used as a first-line therapy for metastatic disease. Research into the molecular characterisation of localised, recurrent, and progressive disease will undoubtedly have an impact on clinical management. Similarly, emerging research into novel therapeutics, such as targeted radioisotopes and immunotherapy, holds much promise for improving the lives of patients with prostate cancer.

Immunophenotype Rearrangement in Response to Tumor Excision May Be Related to the Risk of Biochemical Recurrence in Prostate Cancer Patients

Background: Prostate cancer (PCa) is known to exhibit a wide spectrum of aggressiveness and relatively high immunogenicity. The aim of this study was to examine the effect of tumor excision on immunophenotype rearrangements in peripheral blood and to elucidate if it is associated with biochemical recurrence (BCR) in high risk (HR) and low risk (LR) patients. Methods: Radical prostatectomy (RP) was performed on 108 PCa stage pT2–pT3 patients. Preoperative vs. postoperative (one and three months) immunophenotype profile (T- and B-cell subsets, MDSC, NK, and T reg populations) was compared in peripheral blood of LR and HR groups. Results: The BCR-free survival difference was significant between the HR and LR groups. Postoperative PSA decay rate, defined as ePSA, was significantly slower in the HR group and predicted BCR at cut-off level ePSA = −2.0% d⁻¹ (AUC = 0.85 (95% CI, 0.78–0.90). Three months following tumor excision, the LR group exhibited a recovery of natural killer CD3 − CD16+ CD56+ cells, from 232 cells/µL to 317 cells/µL (p < 0.05), which was not detectable in the HR group. Prostatectomy also resulted in an increased CD8+ population in the LR group, mostly due to CD8+ CD69+ compartment (from 186 cells/µL before surgery to 196 cells/µL three months after, p < 001). The CD8+ CD69+ subset increase without total T cell increase was present in the HR group (p < 0.001). Tumor excision resulted in a myeloid-derived suppressor cell (MDSC) number increase from 12.4 cells/µL to 16.2 cells/µL in the HR group, and no change was detectable in LR patients (p = 0.12). An immune signature of postoperative recovery was more likely to occur in patients undergoing laparoscopic radical prostatectomy (LRP). Open RP (ORP) was associated with increased MDSC numbers (p = 0.002), whereas LRP was characterized by an immunity sparing profile, with no change in MDSC subset (p = 0.16). Conclusion: Tumor excision in prostate cancer patients results in two distinct patterns of immunophenotype rearrangement. The low-risk group is highly responsive, revealing postoperative restoration of T cells, NK cells, and CD8+ CD69+ numbers and the absence of suppressor MDSC increase. The high-risk group presented a limited response, accompanied by a suppressor MDSC increase and CD8+ CD69+ increase. The laparoscopic approach, unlike ORP, did not result in an MDSC increase in the postoperative period.

Does surgery benefit patients with oligometastatic or metastatic prostate cancer? - A retrospective cohort study and meta-analysis

BACKGROUND

To evaluate long-term oncological outcomes of radical prostatectomy (RP) plus androgen deprivation therapy (ADT) in oligometastatic prostate cancer (PCa) patients.

METHODS

Our study included oligometastatic PCa patients hospitalized between January 1, 2010 and December 31, 2015, who received ADT with or without RP. We evaluated survival by employing Kaplan-Meier methods, with log-rank tests and univariate and multivariate Cox regression analyses. A meta-analysis of previously published studies was additionally performed.

RESULTS

The median follow-up times of both groups were 68.4 months (interquartile range = 56.5-85.0). In this cohort study, significant statistical difference in preoperative total prostate-specific antigen (tPSA; p = .121), clinical T stage (p = .115), and N stage (p = .394) were not found between the two groups. Meanwhile, the difference in overall survival (OS) between the two groups did not reach statistical significance (p = .649). A significant difference was not observed in castration-resistant prostate cancer (CRPC)-free survival between two groups as well (p = .183). Numbers of metastases might be an independent prognosis factor (p = .05) for OS, and postoperative tPSA is a risk predictor for CRPC-free survival (p = .032). A meta-analysis of four relevant studies demonstrated significant statistical difference in clinical improvement with RP plus ADT over ADT alone in OS survival (p < .001; hazard ratio [HR] = 0.51; 95% confidence interval [CI] = 0.38-0.69) instead of CRPC-free survival (p = .42; HR = 0.86; 95% CI = 0.59-1.24).

CONCLUSION

The addition of RP to ADT for the treatment of oligometastatic PCa was associated with an improved OS instead of CRPC-free survival.

Oligometastatic prostate cancer treatment

Oligometastatic prostate cancer is an intermediate state between localized disease and widespread metastasis. Its biological and clinical peculiarities are still to be elucidated. New imaging techniques contribute to the detection of patients with oligometastatic disease. PET/CT scanning with prostate-specific membrane antigen can improve the selection of men with true early, low-volume oligometastatic disease, who are candidates for metastasis-directed therapy. Clinical studies demonstrated that androgen deprivation therapy can be delayed in oligometastatic patients with a low tumor burden, although no survival benefit has been demonstrated at present. This article presents available evidence on the treatment strategies for oligometastatic prostate cancer.

Influence of the Position and Composition of Radiometals and Radioiodine Labels on Imaging of Epcam Expression in Prostate Cancer Model Using the DARPin Ec1

Simple Summary

Metastasis-targeting therapy might improve outcomes in oligometastatic prostate cancer. Epithelial cell adhesion molecule (EpCAM) is overexpressed in 40–60% of prostate cancer cases and might be used as a target for specific delivery of toxins and drugs. Radionuclide molecular imaging could enable non-invasive detection of EpCAM and stratification of patients for targeted therapy. Designed ankyrin repeat proteins (DARPins) are scaffold proteins, which can be selected for specific binding to different targets. The DARPin Ec1 binds strongly to EpCAM. To determine an optimal design of Ec1-based probes, we labeled Ec1 at two different positions with four different nuclides (⁶⁸Ga, ¹¹¹In, ⁵⁷Co and ¹²⁵I) and investigated the impact on Ec1 biodistribution. We found that the C-terminus is the best position for labeling and that ¹¹¹In and ¹²⁵I provide the best imaging contrast. This study might be helpful for scientists developing imaging probes based on scaffold proteins.

Abstract

The epithelial cell adhesion molecule (EpCAM) is intensively overexpressed in 40–60% of prostate cancer (PCa) cases and can be used as a target for the delivery of drugs and toxins. The designed ankyrin repeat protein (DARPin) Ec1 has a high affinity to EpCAM (68 pM) and a small size (18 kDa). Radiolabeled Ec1 might be used as a companion diagnostic for the selection of PCa patients for therapy. The study aimed to investigate the influence of radiolabel position (N- or C-terminal) and composition on the targeting and imaging properties of Ec1. Two variants, having an N- or C-terminal cysteine, were produced, site-specifically conjugated to a DOTA chelator and labeled with cobalt-57, gallium-68 or indium-111. Site-specific radioiodination was performed using ((4-hydroxyphenyl)-ethyl)maleimide (HPEM). Biodistribution of eight radiolabeled Ec1-probes was measured in nude mice bearing PCa DU145 xenografts. In all cases, positioning of a label at the C-terminus provided the best tumor-to-organ ratios. The non-residualizing [¹²⁵I]I-HPEM label provided the highest tumor-to-muscle and tumor-to-bone ratios and is more suitable for EpCAM imaging in early-stage PCa. Among the radiometals, indium-111 provided the highest tumor-to-blood, tumor-to-lung and tumor-to-liver ratios and could be used at late-stage PCa. In conclusion, label position and composition are important for the DARPin Ec1.

Assessing the accuracy of 68 Ga-PSMA PET/CT compared with MRI in the initial diagnosis of prostate malignancy: A cohort analysis of 114 consecutive patients

INTRODUCTION

Prostate cancer diagnosis is shifting towards a minimally invasive approach, maintaining accuracy and efficacy while reducing morbidity. We aimed to assess if PSMA-Ga68 PET/CT can accurately grade and localise prostatic malignancy using objective methods, compared with pathology and MRI.

METHODS

Retrospective analysis on 114 consecutive patients undergoing staging PSMA PET/CT scans over 12 months was carried out. The SUVmax and site of highest PSMA activity within the prostate gland were recorded. Pathology/biopsy review assessed maximum Gleason score (and location). MRI analysis assessed the highest PIRADS score and location. The grade, location and size of malignant tissue on biopsy, and PSA, were correlated with the SUVmax and the PIRADS score.

RESULTS

SUVmax was significantly elevated in cases with PSA ≥10 (P = 0.003) and Gleason score ≥8 (P = 0.0002). SUVmax demonstrated equivalent sensitivity to MRI-PIRADS in predicting Gleason ≥8 disease, with higher specificity when tested under a high-specificity regime (SUVmax ≥10, PIRADS = 5, P = 0.002). Furthermore, the region of highest SUVmax was superior to MRI-PIRADS for localising the highest grade tumour region, correctly identifying 71% of highest grade regions compared to 54% with MRI (P = 0.015).

CONCLUSION

PSMA PET/CT is as effective as MRI in identifying high-grade prostate malignancy. Our findings also support previous studies in showing a significant relationship between SUVmax and Gleason grade. These benefits, along with the known advantage in identifying distant metastases and the reduced cost, further support the argument that PSMA PET/CT should be offered as an initial investigation in the workup of prostate cancer.

Definition and Impact on Oncologic Outcomes of Persistently Elevated Prostate-specific Antigen After Salvage Lymph Node Dissection for Node-only Recurrent Prostate Cancer After Radical Prostatectomy: Clinical Implications for Multimodal Therapy

BACKGROUND

The optimal definition and prognostic significance of persistently elevated prostate-specific antigen (PSA) after salvage lymph node dissection (sLND) for node-only recurrent prostate cancer (PCa) remain unknown.

OBJECTIVE

To assess the definition and clinical implications of persistently elevated PSA after sLND for node-only recurrent PCa after radical prostatectomy.

DESIGN, SETTING, AND PARTICIPANTS

The study included 579 patients treated with sLND at 11 high-volume centers between 2000 and 2016.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

We assessed the linear relationship between the first PSA after sLND and death from PCa. Different definitions of PSA persistence were included in a multivariable model predicting cancer-specific mortality (CSM) after surgery to identify the best cutoff value. We investigated the association between PSA persistence and oncologic outcomes using multivariable regression models. Moreover, the effect of early androgen deprivation therapy (ADT) after sLND was tested according to PSA persistence status and estimated risk of CSM.

RESULTS AND LIMITATIONS

We found an inverse relationship between the first PSA after sLND and the probability of cancer-specific survival. PSA persistence defined as first postoperative PSA ≥0.3 ng/ml provided the best discrimination accuracy (C index 0.757). According to this cutoff, 331 patients (57%) experienced PSA persistence. The median follow-up for survivors was 48 mo (interquartile range 27-74). After adjusting for confounders, men with persistently elevated PSA had higher risk of clinical recurrence (hazard ratio [HR] 1.61), overall mortality (HR 2.20), and CSM (HR 2.59; all p < 0.001) after sLND. Early ADT administration after sLND improved survival only for patients with PSA persistence after surgery (HR 0.49; p = 0.024). Similarly, when PSA persistence status was included in multivariable models accounting for pathologic features, early ADT use after sLND was beneficial only for patients with a predicted risk of CSM at 5 yr of >10%.

CONCLUSIONS

PSA persistence after sLND independently predicts adverse prognosis, with the best discrimination accuracy for CSM provided by a definition of PSA ≥ 0.3 ng/ml. We showed that when stratifying patients by final pathology results and PSA persistence status, early ADT use after sLND was beneficial only for patients with PSA persistence or with a calculated 5-yr risk of CSM of >10%, which could be useful as we await results from ongoing prospective trials.

PATIENT SUMMARY

We found that for patients with prostate cancer who had lymph nodes removed after their cancer recurred, persistently elevated prostate-specific antigen (PSA) levels predict poorer prognosis. We showed that a PSA level of ≥0.3 ng/ml provides the best accuracy in identifying patients with worse prognosis. This may help to improve risk stratification after lymph node removal and allow physicians to optimize treatment strategies after surgery.

Evaluation of Quantitative Ga-68 PSMA PET/CT Repeatability of Recurrent Prostate Cancer Lesions Using Both OSEM and Bayesian Penalized Likelihood Reconstruction Algorithms

Rationale: To formally determine the repeatability of Ga-68 PSMA lesion uptake in both relapsing and metastatic tumor. In addition, it was hypothesized that the BPL algorithm Q. Clear has the ability to lower SUV signal variability in the small lesions typically encountered in Ga-68 PSMA PET imaging of prostate cancer. Methods: Patients with biochemical recurrence of prostate cancer were prospectively enrolled in this single center pilot test-retest study and underwent two Ga-68 PSMA PET/CT scans within 7.9 days on average. Lesions were classified as suspected local recurrence, lymph node metastases or bone metastases. Two datasets were generated: one standard PSF + OSEM and one with PSF + BPL reconstruction algorithm. For tumor lesions, SUVmax was determined. Repeatability was formally assessed using Bland–Altman analysis for both BPL and standard reconstruction. Results: A total number of 65 PSMA-positive tumor lesions were found in 23 patients (range 1 to 12 lesions a patient). Overall repeatability in the 65 lesions was −1.5% ± 22.7% (SD) on standard reconstructions and −2.1% ± 29.1% (SD) on BPL reconstructions. Ga-68 PSMA SUVmax had upper and lower limits of agreement of +42.9% and −45.9% for standard reconstructions and +55.0% and −59.1% for BPL reconstructions, respectively (NS). Tumor SUVmax repeatability was dependent on lesion area, with smaller lesions exhibiting poorer repeatability on both standard and BPL reconstructions (F-test, p < 0.0001). Conclusion: A minimum response of 50% seems appropriate in this clinical situation. This is more than the recommended 30% for other radiotracers and clinical situations (PERCIST response criteria). BPL does not seem to lower signal variability in these cases.

Oligorecurrent Prostate Cancer and Stereotactic Body Radiotherapy: Where Are We Now? A Systematic Review and Meta-analysis of Prospective Studies

CONTEXT

The optimal management of oligometastatic prostate cancer (PCa) is still debated.

OBJECTIVE

The purpose of the present systematic review and meta-analysis is to collect the available evidence to date to better define the role of stereotactic body radiotherapy (SBRT) in selected patients with oligorecurrent PCa.

EVIDENCE ACQUISITION

Study methodology complied with the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA). All prospective studies including PCa patients with nodal and/or bone oligometastases (one to five lesions) were considered eligible. Heterogeneity between study-specific estimates was tested using chi-square statistics and measured with the I2 index. A pooled estimate was obtained by fitting both fixed-effect and DerSimonian and Laird random-effect model.

EVIDENCE SYNTHESIS

Overall, six works (two randomized and the remainder observational) published between 2013 and 2020 were considered eligible. Globally, data from 445 patients were incorporated, of whom 396 were treated with SBRT (329 in observational studies and the remaining 67 in randomized ones). Regarding local progression-free survival (PFS), five studies reported values close to 100%, while one reported a value of 80% in the observation arm. The benefit in terms of biochemical PFS brought by SBRT was evident in all considered studies. Such a difference in cumulative probabilities between the intervention arm and the comparator arm is maintained even 24 mo after the baseline. All studies but one considered toxicity among the endpoints of interest. Most events were classified as either G1 or G2, and the only G ≥ 3 adverse event was reported in one trial.

CONCLUSIONS

SBRT is highly cost effective, safe, and with an almost inexistent toxicity risk that makes it the perfect candidate for the optimal management of PCa oligometastatic patients. However, more solid data and a higher level of evidence are needed to affirm its role in the management of these patients.

PATIENT SUMMARY

In this work, we reviewed available evidence on the use of stereotactic body radiotherapy in treating oligometastatic prostate cancer patients. We found good evidence that radiotherapy brings important benefits in overall treatment efficacy without major side effects.

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 external beam radiation therapy for oligometastatic prostate cancer: A combination of prostate-targeted treatment and metastasis-directed therapy

OBJECTIVE

To assess the efficacy of combination of prostate-targeted treatment and metastasis-directed therapy for oligometastatic prostate cancer.

METHODS

We retrospectively evaluated the clinical outcomes of synchronously diagnosed oligometastatic prostate cancer patients treated with external beam radiation therapy for the prostate and all metastatic lesions (≤3 lesions) at Kyoto University Hospital between January 2004 and April 2019. The prescribed dose was basically ≥70 Gy for the prostate with or without whole pelvic irradiation, and ≥45 Gy for the metastatic lesions. Clinical outcomes were compared with a contemporary cohort of 55 synchronous oligometastatic prostate cancer patients treated with the standard of care.

RESULTS

In total, 16 consecutive patients with synchronous oligometastatic prostate cancer were analyzed. The median follow-up period was 7.4 years. The 8-year overall survival, prostate cancer-specific survival, biochemical failure-free, clinical failure-free and castration-resistant prostate cancer-free rates were 64.8%, 71.3%, 38.5%, 47.3% and 67.3%, respectively. No grade 3 or higher radiation-induced late toxicities occurred. Patients with prostate-targeted treatment plus metastasis-directed therapy had a significantly higher castration-resistant prostate cancer-free rate than those without prostate-targeted treatment plus metastasis-directed therapy (P = 0.00741).

CONCLUSIONS

Prostate-targeted treatment plus metastasis-directed therapy through external beam radiation therapy can result in favorable long-term disease-free and survival outcomes with acceptable morbidities among synchronous oligometastatic prostate cancer patients. Therefore, this approach may represent a promising treatment strategy for this population. Further investigation is required.

Detection efficacy of 18F-rhPSMA-7.3 PET/CT and impact on patient management in patients with biochemical recurrence of prostate cancer after radical prostatectomy and prior to potential salvage treatment

Purpose: Radiohybrid prostate-specific membrane antigen (rhPSMA) ligands are a new class of 18F-labeled PSMA-targeting agents. 18F-rhPSMA-7.3 is a lead compound which is currently under investigation in two multicenter phase III trials for PET-imaging. Here, we report the first retrospective data on its detection efficacy and potential impact on clinical management in a homogeneous cohort of patients with biochemical recurrence after radical prostatectomy, and prior to any salvage therapy. Methods: 242 patients (median [range] PSA, 0.60 [0.2-60.8] ng/mL) who underwent 18F-rhPSMA-7.3 PET/CT were retrospectively selected from the institutions' database. Images were re-read by an experienced nuclear medicine physician. Lesion detection rates were stratified by PSA. Further, potential management before and after PET was assessed by an interdisciplinary simulated tumor board and categorized (major vs. minor vs. no therapeutic change). The distribution of management change identified in each PSA subgroup was determined. Results: In total, 176/242 (72.7%) patients showed PSMA-ligand positive findings. 18F-rhPSMA-7.3 detection rates were 61.8% (63/102), 67.9% (38/56), 81.1% (30/37) and 95.7% (45/47) for PSA-levels of 0.2-<0.5 ng/mL, 0.5-<1 ng/mL, 1-<2 ng/mL and ≥2 ng/mL, respectively. 18F-rhPSMA-7.3 PET/CT revealed local recurrence, pelvic lymph node metastases, retroperitoneal lymph nodes metastases, supradiaphragmatic lymph nodes, bone metastases, and visceral metastases in 48.8% (n = 118), 28.9% (n = 70), 6.6% (n = 16), 1.2% (n = 3), 13.2% (n = 32) and 1.2% (n = 3) of patients, respectively. Notably, bone lesions were identified in 8.8% of patients (9/102) with PSA <0.5 ng/mL. Results from the interdisciplinary simulated tumor board indicated change of therapeutic management in 153/242 patients (63.2%) with 54/242 (22.3%) considered major and 99/242 (40.9%) minor, respectively. 18F-rhPSMA-7.3 PET/CT did not prompt any therapeutic changes in 64/242 patients (26.4%). Conclusion: 18F-rhPSMA-7.3 PET offers high detection efficacy in patients with biochemical recurrence after radical prostatectomy, and prior to potential salvage therapy, and results in a potential change in treatment plans in nearly 2/3 of patients. Keywords: Biochemical recurrence; hybrid imaging; positron emission tomography; prostate cancer; prostate-specific membrane antigen.

Oligometastatic Prostate Adenocarcinoma. Clinical-Pathologic Study of a Histologically Under-Recognized Prostate Cancer

The clinical parameters and the histological and immunohistochemical findings of a prospective protocolized series of 27 prostate carcinoma patients with oligometastatic disease followed homogeneously were analyzed. Lymph nodes (81.5%) and bones (18.5%) were the only metastatic sites. Local control after metastatic directed treatment was achieved in 22 (81.5%) patients. A total of 8 (29.6%) patients developed castration-resistant prostate cancer. Seventeen (63%) patients presented with non-organ confined disease. The Gleason index 8-10 was the most frequently observed (12 cases, 44.4%) combined grade. Positive immunostainings were detected with androgen receptor (100%), PGP 9.5 (74%), ERG (40.7%), chromogranin A (29.6%), and synaptophysin (18.5%) antibodies. The Ki-67 index value > 5% was observed in 15% of the cases. L1CAM immunostaining was negative in all cases. Fisher exact test showed that successful local control of metastases was associated to mild inflammation, organ confined disease, Ki-67 index < 5%, and Gleason index 3 + 3. A castration resistant status was associated with severe inflammation, atrophy, a Gleason index higher than 3 + 3, Ki-67 index ≥ 5%, and positive PGP 9.5, chromogranin A, and synaptophysin immunostainings. In conclusion, oligometastatic prostate adenocarcinoma does not have a specific clinical-pathologic profile. However, some histologic and immunohistochemical parameters of routine use may help with making therapeutic decisions.

Newly Diagnosed Oligometastatic Prostate Cancer: Current Controversies and Future Developments

This report presents a 56-yr-old man in good general health status, newly diagnosed with a cT3b, cN1, cM1b, International Society of Urological Pathology grade group 3, low-volume (CHAARTED criteria), low-risk (LATITUDE criteria) metastatic prostate cancer. Staging was performed with conventional imaging: a computed tomography (CT) scan showed the presence of two enlarged lymph nodes on the left, close to the external iliac vessels. In addition, a suspicious 15-mm metastatic lesion was detected in the left pubic bone. This lesion was confirmed on the bone scan, without further metastatic lesions. In the context of a clinical trial, after an initial course of androgen deprivation therapy (ADT), the patient was treated with robot-assisted radical prostatectomy and extended pelvic lymph node dissection (histopathological examination: ypT3b pN1 R1). Postprostatectomy radiation therapy was delivered on prostatic bed (70Gy), pelvic lymph node area (54Gy), and pubic bone (51Gy). ADT was scheduled for a total period of 36 mo. Currently, the patient is still receiving ADT, which will be completed within 6 mo. The last prostate-specific antigen level was undetectable. The discussion is focused on the following three open questions: (1) Would molecular imaging (eg, prostate-specific membrane antigen positron emission tomography/CT) change the therapeutic approach to the patient? (2) Is there a role for local treatment in the metastatic setting? (iii) Should metastasis-directed therapy be considered for this patient? PATIENT SUMMARY: The optimal management of patients newly diagnosed with oligometastatic prostate cancer remains challenging. The fields of staging with modern imaging and therapy with novel treatment options are evolving rapidly. In particular, the role of a prostate-specific membrane antigen positron emission tomography/computed tomography scan for primary staging, the impact of a local treatment on the prostate, and the effect of direct therapies on the metastases represent important open questions in this intriguing field.

Oncological Outcome of Combining Cytoreductive Prostatectomy and Metastasis-Directed Radiotherapy in Patients with Prostate Cancer and Bone Oligometastases: A Retrospective Cohort Study

Background

The current standard of care for metastatic prostate cancer (mPCa) is androgen deprivation therapy (ADT) with or without anti-androgen and chemotherapy. The aim of this study was to evaluate the efficacy and safety of a multimodal approach including local primary tumor therapy, metastasis-directed therapy (MDT), and hormonal therapy in patients with oligometastatic prostate cancer (PCa).

Methods

We reviewed data of patients with PCa and bone oligometastases at diagnosis treated in three institutions with ADT followed by cytoreductive surgery with or without metastases-directed radiotherapy. Oligometastases were defined as the presence of five or fewer metastatic lesions with the absence of visceral metastases. In this retrospective cohort study, 58 patients underwent cytoreductive radical prostatectomy and ADT. Of these, 26 patients (45%) received stereotactic body radiation therapy (SBRT) to all metastatic sites as a MDT. Oncological outcomes were analyzed using the Kaplan–Meier method.

Results

The median follow-up period was 46.2 months. Of the 58 patients, the 3-year castration-resistant prostate cancer (CRPC)-free survival and cancer-specific survival was 75.9% and 91.4%, respectively. Pre- or post-treatment predictive factors for progression to CRPC, including prostate-specific antigen (PSA) level at diagnosis ≥20 ng/mL, Gleason grade groups 5, clinical T stage cT3b-4, PSA nadir level of ≥0.05 ng/mL, and no MDT with SBRT, were significantly associated with progression to CRPC. Subgroup analysis showed that the MDT group had significantly better CRPC-free survival than the non-MDT group with Gleason grade groups 1–4 (HR=0.228; 95% CI= 0.056–0.926). A total of 3.4% of the patients had grade 2 acute genitourinary toxicities and 5.2% had grade 2 acute gastrointestinal toxicities. No late grade >2 adverse events were observed.

Conclusion

This multi-center, retrospective cohort study revealed the feasibility of combining cytoreductive prostatectomy and metastasis-directed radiotherapy for newly-diagnosed oligometastatic PCa. This treatment strategy has the potential to delay the progression to CRPC.

PROACTA: a survey on the actual attitude of the Italian radiation oncologists in the management and prescription of hormonal therapy in prostate cancer patients

AIM

To investigate the actual attitude of Radiation Oncologists in the prescription of hormonal therapy in prostate cancer (PC) with or without Radiation Therapy (RT).

MATERIALS AND METHODS

In 2019, a survey named Prescription of Radiation Oncologists ACtual Attitude including 18 items was sent to all Italian Radiation Oncologists of the Italian Association of Radiotherapy and Clinical Oncology. The first 4 items were about the Radiation Oncology Centers characteristics and years of practice of the respondents. The remaining 14 items concerned the setting in which hormone therapy was prescribed in PC patients (radical, postprostatectomy/oligometastatic state), the kind of drug, the choice modality (Multidisciplinary Group/autonomy decision) and other factors.

RESULTS

A total of 127 questionnaires were returned, mainly by Northern Italy Radiation Oncology Centres (44.9%), and by experienced Radiation Oncologists (78%), who declared to prescribe independently hormone therapy in 85.8% of cases. The Androgen deprivation therapy (ADT) prescription in castration naive PC was made independently by 56.7% of respondents and associated with radical RT, postoperative or salvage RT according to various risk factors. In castration-sensitive oligorecurrent PC, the majority (51.2%) administered ADT only if local ablative treatment was not feasible, while in metastatic castration resistant disease novel hormone therapy use was established in almost half of cases within multidisciplinary board. Radiation Oncologists could prescribe these drugs independently in 64% of cases.

CONCLUSION

Our survey established the prescription attitude of ADT and new hormonal agents (abiraterone, enzalutamide, apalutamide) by Italian Radiation Oncologists and highlighted the importance of expertise in global PC management.

Oncological Outcomes of Metastasis-Directed Therapy in Oligorecurrent Prostate Cancer Patients Following Radical Prostatectomy

Several retrospective and a few prospective studies have shown that metastasis-directed therapy (MDT) could delay clinical progression and postpone the initiation of systemic treatment in oligorecurrent prostate cancer (PCa) patients. However, these endpoints are strongly influenced by variables such as concomitant use of androgen deprivation therapy (ADT) and follow-up imaging protocols. The aim of this manuscript was to assess palliative ADT- and metastatic castration-resistant prostate cancer (mCRPC)-free survival as long-term oncological outcomes in oligorecurrent PCa treated by MDT. We retrospectively identified consecutive post-prostatectomy oligorecurrent PCa patients treated by MDT (salvage lymphadenectomy, radiotherapy, or metastasectomy) at our tertiary referral center. Patients were eligible for inclusion if they developed recurrence following radical prostatectomy, had ≤5 metastatic lesions on imaging and had a serum testosterone >50 ng/dL or a testosterone suppression therapy-free interval of >2 years prior to the first MDT as an assumption of recovered serum testosterone (if no testosterone measurement available). Patients with castration-resistant or synchronous oligometastatic PCa at the time of first MDT were excluded. Repeated MDTs were allowed, as well as a period of concomitant ADT. Kaplan-Meier analyses were performed to assess palliative ADT-free and mCRPC-free survival. We identified 191 eligible patients who underwent MDT. Median follow-up from first MDT until last follow-up or death was 45 months (IQR 27-70; mean 51 months). Estimated median palliative-ADT free survival was 66 months (95% CI 58-164) and estimated median mCRPC-free survival was not reached (mean 117 months, 95% CI 103-132). In total, 314 MDTs were performed and 25 patients (13%) received ≥3 MDTs. This study demonstrated that (repeated) MDT is feasible and holds promise in terms of palliative ADT-free and mCRPC-free survival for patients with oligorecurrent PCa. However, these findings should be confirmed in prospective randomized controlled trials.

Prostate-specific Membrane Antigen PET: Therapy Response Assessment in Metastatic Prostate Cancer

Therapy response assessment is a critical step in cancer management, leading clinicians to optimize the use of therapeutic options during the course of the disease. Imaging is a pivotal biomarker for therapy response evaluation in oncology and has gained wider use through the development of reproducible data-based guidelines, of which the Response Evaluation Criteria in Solid Tumors is the most successful example. Disease-specific criteria have also been proposed, and the Prostate Cancer Working Group 3 criteria are the mainstay for prostate cancer (PC). However, conventional imaging evaluation in metastatic PC has several limitations, including (a) the inability to detect small-volume disease, (b) the high prevalence of bone (nonmeasurable) lesions at imaging, and (c) the established role of serum prostate-specific antigen (PSA) levels as the biomarker of choice for response assessment and disease progression. In addition, there are an increasing number of newer treatment options with various effects on imaging features. Prostate-specific membrane antigen (PSMA) PET has improved patient selection for newer treatments, such as metastasis-directed therapy (MDT) or radionuclide therapy. The role of PSMA PET in response assessment for many metastatic PC therapeutic options (MDT, androgen deprivation therapy, chemotherapy, radionuclide therapy, and immunotherapy) is an evolving issue, with emerging data showing good correlation with PSA levels and clinical outcome. However, there are specific implications of each therapy (especially androgen deprivation therapy and immunotherapy) on PSMA expression by PC cells, leading to potential pitfalls and inaccuracies that must be known by radiologists. Despite some limitations, PSMA PET is addressing gaps left by conventional imaging methods (eg, CT and bone scanning) and nonimaging biomarkers (PSA levels) in metastatic PC therapy response assessment, a role that can be improved with advances like refinement of interpretation criteria and whole-body tumor burden quantification.^© RSNA, 2020See discussion on this article by Barwick and Castellucci.

Long-term clinical outcomes of salvage pelvic radiation therapy for oligo-recurrent pelvic lymph nodes after definitive external-beam radiation therapy for non-metastatic prostate cancer

Although salvage external-beam radiation therapy (EBRT) is an attractive treatment option for pelvic lymph nodal recurrence (PeNR) in patients with prostate cancer (PCa), limited data are available regarding its long-term efficacy. This study examined the long-term clinical outcomes of patients who underwent salvage pelvic radiation therapy (sPRT) for oligo-recurrent pelvic lymph nodes after definitive EBRT for non-metastatic PCa. Patients who developed PeNR after definitive EBRT and were subsequently treated with sPRT at our institution between November 2007 and December 2015 were retrospectively analyzed. The prescribed dose was 45-50.4 Gy (1.8-2 Gy per fraction) to the upper pelvis, with up to 54-66 Gy (1.8-2 Gy per fraction) for recurrent nodes. Long-term hormonal therapy was used as neoadjuvant and/or adjuvant therapy. The study population consisted of 12 consecutive patients with PeNR after definitive EBRT (median age: 73 years). The median follow-up period was 58.9 months. The 5-year overall survival, PCa-specific survival, biochemical failure-free, clinical failure-free, and castration-resistant PCa-free rates were 82.5, 100.0, 62.3, 81.8, and 81.8%, respectively. No grade 2 or higher sPRT-related late toxicities occurred. In conclusion, more than half of the study patients treated with sPRT had a long-term disease-free status with acceptable morbidities. Moreover, most of the patients maintained hormonal sensitivity. Therefore, this approach may be a promising treatment method for oligo-recurrent pelvic lymph nodes.

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.

Assessing the Best Surgical Template at Salvage Pelvic Lymph Node Dissection for Nodal Recurrence of Prostate Cancer After Radical Prostatectomy: When Can Bilateral Dissection be Omitted? Results from a Multi-institutional Series

The best surgical template for salvage pelvic lymph node dissection (sLND) in patients with nodal recurrence from prostate cancer (PCa) after radical prostatectomy (RP) is currently unknown. We analyzed data of 189 patients with a unilateral positive positron emission tomography (PET) scan of the pelvic lymph node areas, who were treated with bilateral pelvic sLND after RP at 11 high-volume centers. The primary endpoint was missed contralateral disease at final pathology, defined as lymph node positive for PCa in the side opposite to the positive spot(s) at the PET scan. Overall, 93 (49%) and 96 (51%) patients received a ¹¹C-choline and a ⁶⁸Ga prostate-specific membrane antigen (PSMA) PET scan, respectively, and 171 (90%) and 18 (10%) men had one and two positive spots, respectively. The rate of missed contralateral PCa was 18% (34/189), with the rates being 17% (29/171) and 28% (5/18) in men with one and two positive spots, respectively. While the rate of contralateral disease did not differ between ⁶⁸Ga-PSMA and ¹¹C-choline (29% and 27%, respectively) among men with two positive spots, the rate of contralateral PCa was only 6% with ⁶⁸Ga-PSMA versus 28% with ¹¹C-choline in patients with a single positive spot. This finding was confirmed at multivariable logistic regression analysis predicting missed disease at final pathology after accounting for confounders (odds ratio: 0.24; p =  0.001). However, in men with a single positive spot at ⁶⁸Ga-PSMA PET/computed tomography, the rate of single confirmed lymph node metastasis at final pathology was only 33%, suggesting the need for extended template even if unilateral dissection is performed. Awaiting confirmatory studies, patients diagnosed with a single positive spot at the ⁶⁸Ga-PSMA PET scan might be considered for unilateral extended pelvic sLND. PATIENT SUMMARY: We assessed the risk of missing contralateral disease in patients with a positron emission tomography (PET) scan suggestive of unilateral nodal recurrence from prostate cancer (PCa) after radical prostatectomy and who were treated with bilateral salvage lymph node dissection (sLND). Variability exists according to the number of positive spots and PET tracer, with the lowest rate of missed PCa in men diagnosed with a single positive spot at a ⁶⁸Ga prostate-specific membrane antigen PET scan (6%). If replicated, our data suggest that these patients might be considered for unilateral extended pelvic sLND.