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

The expanding role of next-generation imaging in prostate cancer management: a cross-sectional survey exploring the clinical practice of uro-oncologists in North-Eastern Italy; on behalf of GUONE (Gruppo Uro-Oncologico del Nord-Est)

Background

Next-generation imaging (NGI) technologies such as multiparametric magnetic resonance imaging (mpMRI) and total-body NGI (tbNGI) methodologies including choline, fluciclovine or PSMA positron emission tomography/computed tomography (PET/CT), whole-body MRI (wbMRI), and PET/MRI are becoming increasingly available, but their use in different prostate cancer (PCa) settings is under debate. The Gruppo Uro-Oncologico del Nord-Est (GUONE) designed a survey to explore the current clinical practice of NGI utilization in a specific macro-region in North-Eastern Italy.

Methods

A cross-sectional survey was conducted by administering an anonymous online multiple-choice questionnaire to uro-oncologists practicing in North-Eastern Italy, using the Google Forms® platform. The use of NGI was investigated in the following settings: primary staging of PCa; management of biochemical (BCR) and local recurrence (LR); re-staging in metastatic hormone-sensitive PCa (mHSPC), metastatic castration-resistant PCa (mCRPC), non-metastatic CRPC (nmCRPC), and oligometastatic PCa (OMPC).

Results

In all, 100 uro-oncologists accessed and completed the survey. In primary N/M staging, the use of tbNGI increases in accordance with NCCN risk groups. Re-staging with choline and PSMA PET/CT is the prevalent choice in the case of BCR after radical prostatectomy. Moreover, when the PSA value rises, there is a parallel increased use of tbNGI. When an LR is suspected, PSMA PET/CT plus mpMRI is the most selected option. Re-staging with tbNGI (PSMA PET/CT) is preferred in mHSPC, mCRPC, and nmCRPC patients in case of progression of disease. Overall, there is a limited use of wbMRI and PET/MRI in all the settings investigated.

Conclusion

Our survey describes the expanding role of NGI modalities in the management of PCa patients, from primary staging and re-staging to management of advanced PCa and assessment of treatment response. Several controversial issues have emerged, which need to be addressed in prospective studies to develop a standardized and cost-effective NGI utilization.

Stereotactic body radiotherapy as metastasis-directed therapy in oligometastatic prostate cancer: a systematic review and meta-analysis of randomized controlled trials

BACKGROUND

The use of stereotactic body radiotherapy (SBRT) to definitively treat oligometastases in prostate cancer has drawn large clinical and research interests within radiation oncology. However, the evidence is considered in its early stages and there is currently no systematic review of randomized controlled trials (RCTs) in this field. We aimed to evaluate the efficacy and safety of SBRT as metastasis-directed therapy (MDT) in oligometastatic prostate cancer (OMPC) compared to no MDT reported in RCTs.

METHODS

MEDLINE, Embase, CINAHL Complete, and Cochrane Library were searched on October 28, 2023. Eligible studies were RCTs comparing SBRT as MDT with no MDT in extracranial OMPC, without restrictions on follow-up time, publication status, language, or year. Participant subsets fulfilling the eligibility criteria were included. Critical outcomes were overall survival and grade ≥ 3 toxicity, and additional important outcomes were progression-free survival (PFS), local control, grade 5 toxicity, health-related quality of life, and systemic therapy-free survival. Meta-analyses were planned. Risk of bias was assessed using the Cochrane risk-of-bias tool version 2, and the quality of evidence using the Grading of Recommendations Assessment, Development, and Evaluation.

RESULTS

In total, 1825 unique study reports were identified and seven phase II RCTs with 559 eligible participants were included. Four trials included multiple types of primary cancer. Outcome definitions were heterogeneous except for overall survival and toxicity. For overall survival, only one study reported events in both arms. Meta-analysis of the grade ≥ 3 toxicity results from two trials showed no difference (pooled risk ratio 0.78, 95% confidence interval 0.37-1.65, p = 0.52). Four trials reported significantly longer PFS, with a pooled hazard ratio of 0.31 (95% confidence interval 0.21-0.45, p < 0.00001). Risk of bias was of some concerns or high. Quality of evidence was low or moderate.

CONCLUSIONS

Phase II trials have shown promising improvements in PFS for several OMPC states without excess toxicity. Overall survival comparisons are immature. In future confirmatory phase III trials, adequately large sample sizes, blinding of outcome assessors, and/or increased adherence to assigned intervention could improve the quality of evidence. PROSPERO registration number: CRD42021230131.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

The current role of precision surgery in oligometastatic prostate cancer

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

Current management of radiation cystitis after pelvic radiotherapy: a systematic review

INTRODUCTION

We aimed to summarize current literature about radiation cystitis treatments, providing physician of a summary of current management options.

EVIDENCE ACQUISITION

A systematic literature review searching on PubMed (Medline), Scopus, and Web of Science databases was performed in March 2021. PRISMA guidelines were followed. Population consisted of patients with a diagnosis of radiation cystitis after pelvic radiotherapy (P). We focused our attention on different treatments, such as conservative or surgical one (I). Single or multiple arms studies were deemed eligible with no mandatory comparison (C). Main outcomes of interest were symptoms control and adverse events rates (O).

EVIDENCE SYNTHESIS

The search identified 1,194 records. Of all, four studies focused on the use of hyperbaric oxygen therapy showing complete response rates ranging from 52 to 87% approximately. Oral administration of cranberry compounds was investigated in one study showing no superiority to placebo. Intravesical instillation of different compounds were investigated in five studies showing the highest complete response rates after alum (60%) and formalin administration (75%). Endoscopic conservative surgical treatments (fibrin glue or vaporization) also showed 75% complete response rates. In patients who did not respond to conservative treatments robotic cystectomy is feasible with overall complication rates of about 59.3% at 90 days.

CONCLUSIONS

Radiotherapy induced cystitis is an under-reported condition after pelvic radiotherapy. Several treatments have been proposed, but in up to 10% of cases salvage cystectomy is necessary. A stepwise approach, with progressive treatment aggressiveness is recommended.

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.

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.