Comparative Efficacy of Combined Radiotherapy, Systemic Therapy, and Androgen Deprivation Therapy for Metastatic Hormone-Sensitive Prostate Cancer: A Network Meta-Analysis and Systematic Review

Indication and perspectives of radiation therapy in the setting of de-novo metastatic prostate cancer

Prostate cancer is the most common cancer and the third leading cause of cancer mortality in men. Each year, approximately 10% of prostate cancers are diagnosed metastatic at initial presentation. The standard treatment option for de-novo metastatic prostate cancer is androgen deprivation therapy with novel hormonal agent or with chemotherapy. Recently, PEACE-1 trial highlighted the benefit of triplet therapy resulting in the combination of androgen deprivation therapy combined with docetaxel and abiraterone. Radiotherapy can be proposed in a curative intent or to treat local symptomatic disease. Nowadays, radiotherapy of the primary disease is only recommended for de novo low-burden/low-volume metastatic prostate cancer, as defined in the CHAARTED criteria. However, studies on stereotactic radiotherapy on oligometastases have shown that this therapeutic approach is feasible and well tolerated. Prospective research currently focuses on the benefit of intensification by combining treatment of the metastatic sites and the primary all together. The contribution of metabolic imaging to better define the target volumes and specify the oligometastatic character allows a better selection of patients. This article aims to define indications of radiotherapy and perspectives of this therapeutic option for de-novo metastatic prostate cancer.

Efficacy of Treatment for Metastatic Hormone-Sensitive Prostate Cancer: An Umbrella Review of Systematic Reviews and Meta-Analyses

PURPOSE

This umbrella review focused on evaluating the efficacy and adverse events of the metastatic hormone-sensitive prostate cancer patients receiving any treatment regimens, including ADT alone or combination treatments.

METHODS

This study conducted an umbrella review following the PRISMA 2020 checklist, aiming to summarize the available studies to evaluate the efficacy of medical treatments for metastatic hormone-sensitive prostate cancer. A literature search was performed to identify systematic reviews and meta-analyses (SRMAs) that included only randomized controlled trials (RCTs) up to September 2023. This study summarized their findings, evaluated overlapping data (i.e., the same RCTs were included in >one SRMA), tested for excessive significance (i.e., observed number of statistically significant studies > expected number by chance) and assessed the quality of the studies.

RESULTS

A total of 4191 studies were identified, but only 27 were included. Among those 27 studies, 12 were network meta-analyses and 15 were direct meta-analyses. Most studies showed no statistically significant difference in overall mortality among GnRH agonists, antagonists and bilateral orchiectomy. Combination treatment is more beneficial than ADT alone in both OS and PFS outcomes with more adverse events. Nevertheless, there is no OS advantage of any combination regimen over the others.

CONCLUSION

Combination treatments demonstrated clear benefits in OS and PFS over ADT alone with more AEs. Further studies are needed to compare among combination treatments.

Systemic therapies for high-volume metastatic hormone-sensitive prostate cancer: a network meta-analysis

BACKGROUND

We compared the effectiveness of currently available systemic therapies for high-volume metastatic hormone-sensitive prostate cancer (mHSPC) and aimed to establish the optimal treatment regimen.

MATERIAL AND METHODS

We searched multiple databases for randomized controlled trials (RCTs) that evaluated the efficacy of systemic therapy in patients with high-volume mHSPC. Bayesian network meta-analysis was used to indirectly compare overall survival (OS) and progression-free survival (PFS) of various systemic therapies.

RESULTS

Eleven RCTs (6708 participants) finally met the eligibility criteria. Compared with androgen deprivation therapy (ADT) alone, rezvilutamide (REZ) [hazard ratio (HR) = 0.58, 95% confidence interval (CI): 0.44-0.77], abiraterone (ABI) (HR = 0.61, 95% CI: 0.53-0.71), apalutamide (APA) (HR = 0.70, 95% CI: 0.56-0.88), enzalutamide (ENZ) (HR = 0.65, 95% CI: 0.53-0.80), docetaxel (DOC) (HR = 0.72, 95% CI: 0.63-0.84), darolutamide (DAR) + DOC (HR = 0.49, 95% CI: 0.39-0.62), and ABI + DOC (HR = 0.52, 95% CI: 0.38-0.71) significantly improved OS in patients with high-volume mHSPC. Compared with DOC, no advantages were observed for doublet therapies, including REZ, ABI, APA, and ENZ on the basis of ADT, whereas DAR + DOC (HR = 0.68, 95% CI: 0.57-0.82) and ABI + DOC (HR = 0.72, 95% CI: 0.55-0.95) was associated with better OS. The ranking analysis showed that triplet therapy (DAR + DOC + ADT and ABI + DOC + ADT) had the greatest improvement in OS, followed by REZ + ADT. All the regimens showed improved PFS in patients with high-volume mHSPC. Compared with DOC, significant differences were detected for DAR + DOC, ABI + DOC, ENZ + DOC, REZ, and ENZ. According to the ranking analysis, triplet therapy ranked first, followed by ENZ and REZ.

CONCLUSIONS

REZ + ADT were the highest ranked doublet therapy for improvement in OS of patients with high-volume mHSPC, second only to triplet therapy (DAR + DOC + ADT and ABI + DOC + ADT).

Personalizing approaches to the management of metastatic hormone sensitive prostate cancer: role of advanced imaging, genetics and therapeutics

PURPOSE

To summarize contemporary and emerging strategies for the diagnosis and management of metastatic hormone sensitive prostate cancer (mHSPC), focusing on diagnostic testing and therapeutics.

METHODS

Literature review using PUBMED-Medline databases as well as clinicaltrials.gov to include reported or ongoing clinical trials on treatment for mHSPC. We prioritized the findings from phase III randomized clinical trials, systematic reviews, meta-analyses and clinical practice guidelines.

RESULTS

There have been significant changes to the diagnosis and staging evaluation of mHSPC with the integration of increasingly accurate positron emission tomography (PET) imaging tracers that exceed the performance of conventional computerized tomography (CT) and bone scan. Germline multigene testing is recommended for the evaluation of patients newly diagnosed with mHSPC given the prevalence of actionable alterations that may create candidacy for specific therapies. Although androgen deprivation therapy (ADT) remains the backbone of treatment for mHSPC, approaches to first-line treatment include the integration of multiple agents including androgen receptor synthesis inhibitors (ARSI; abiraterone) Androgen Receptor antagonists (enzalutamide, darolutamide, apalautamide), and docetaxel chemotherapy. The combination of ADT, ARSI, and docetaxel chemotherapy has recently been evaluated in a randomized trial and was associated with significantly improved overall survival including in patients with a high burden of disease. The role of local treatment to the prostate with radiation has been evaluated in randomized trials with additional studies underway evaluating the role of cytoreductive radical prostatectomy.

CONCLUSION

The staging and initial management of patients with mHSPC has undergone significant advances in the last decade with advancements in the diagnosis, treatment and sequencing of therapies.

Docetaxel versus abiraterone for metastatic hormone-sensitive prostate cancer with focus on efficacy of sequential therapy

PURPOSE

We aimed to assess the oncologic efficacy of combining docetaxel (DOC) versus abiraterone (ABI) with androgen deprivation therapy (ADT) in patients with high-risk metastatic hormone-sensitive prostate cancer (mHSPC), with a focus on the efficacy of sequential therapy, in a real-world clinical practice setting.

METHODS

The records of 336 patients who harbored de novo high-risk mHSPC, based on the LATITUDE criteria, and had received ADT with either DOC (n = 109) or ABI (n = 227) were retrospectively analyzed. Overall survival (OS), cancer-specific survival (CSS), progression-free survival (PFS), including time to castration-resistant prostate cancer (CRPC), time to 2nd-line progression (PFS2), and 2nd- and 3rd-line PFS, were compared. We used one-to-two propensity score matching to minimize the confounders. The differential efficacy of 2nd-line therapy based on agents in each arm was evaluated using the unmatched cohort as an additional interest.

RESULTS

After propensity score matching, 86 patients treated with DOC + ADT and 172 with ABI + ADT were available for analyses. The 3-year OS and CSS for DOC versus ABI were 76.2% versus 75.1% (p = 0.8) and 78.2% versus 78.6% (p = 1), respectively. There was no difference in the median PFS2 (49 vs. 43 months, p = 0.39), while the median time to CRPC in patients treated with ABI was significantly longer compared to those treated with DOC (42 vs. 22 months; p = 0.006). The median 2nd-line PFS (14 vs. 4 months, p < 0.001) and 3rd-line PFS (4 vs. 2 months, p = 0.012) were significantly better in the DOC group than in the ABI group. Among the unmatched cohort, after ABI for mHSPC, the median 2nd-line PFS did not differ between the patients treated with DOC and those treated with enzalutamide as 2nd-line therapy (both 3 months, p = 0.8).

CONCLUSIONS

ADT with DOC or ABI has comparable oncologic outcomes in terms of OS, CSS, and PFS2 in patients with de novo high-risk mHSPC. Compared to DOC, ABI resulted in longer time to CRPC but worse 2nd and 3rd-line PFS. Further studies are needed to clarify the optimal sequence of therapy in the upfront intensive treatment era.

Comparison of doublet and triplet therapies for metastatic hormone-sensitive prostate cancer: A systematic review and network meta-analysis

Background

The best choice of first-line treatment for metastatic hormone-sensitive prostate cancer (mHSPC) is unclear. We aimed to compare the effectiveness and safety determined in randomized clinical trials of doublet and triplet treatments for mHSPC.

Methods

Medline, Embase, Cochrane Central and ClinicalTrials.gov were searched from inception through July 01, 2022. Eligible studies were phase III randomized clinical trials evaluating androgen deprivation treatment (ADT) alone, doublet therapies [ADT combined with docetaxel (DOC), novel hormonal agents (NHAs), or radiotherapy (RT)], or triplet therapies (NHA+DOC+ADT) as first-line treatments for mHSPC. Outcomes of interest included overall survival (OS), progression-free survival (PFS) and grades 3-5 adverse events (AEs). Subgroup analyses were performed based on tumor burden. The effects of competing treatments were assessed by Bayesian network meta-analysis using R software.

Results

Ten trials with 12,298 patients comparing nine treatments were included. Darolutamide (DARO) +DOC+ADT ranked best in terms of OS benefits (OR 0·52 [95% CI 0·39-0·70]), but its advantages were all statistically insignificant compared with other therapy options except for DOC+ADT (OR 0·68 [95% CI 0·53-0·88]) and RT+ADT (OR 0·57 [95% CI 0·40-0·80]). In terms of PFS, enzalutamide(ENZA)+DOC+ADT (OR 0·32 [95% CI 0·24-0·44]) and abiraterone and prednisone (AAP) +DOC+ADT (OR 0·33 [95% CI 0·25-0·45]) ranked best. For patients with high volume disease (HVD), low volume disease (LVD), and visceral metastases, the optimal therapies were AAP+DOC+ADT (OR 0·52 [95% CI 0·33-0·83]), apalutamide+ADT (OR 0·52 [95% CI 0·26-1·05]) and DARO+DOC+ADT (OR 0·42 [95% CI 0·13-1·34]), respectively. For safety, AAP+DOC+ADT (OR 3·56 [95% CI 1·51-8·43]) ranked worst with the highest risk of grade 3-5 AEs.

Conclusions

Triple therapies may further improve OS and PFS but may be associated with a decrease in safety. Triplet therapies could be suggested for HVD patients, while doublet combinations should still be preferred for LVD patients.

Systematic Review Registration

https://www.crd.york.ac.uk/PROSPEROFILES/303117_STRATEGY_20220202.pdf, identifier CRD4202303117.

Androgen Receptor Signaling Inhibitors in Addition to Docetaxel with Androgen Deprivation Therapy for Metastatic Hormone-sensitive Prostate Cancer: A Systematic Review and Meta-analysis

CONTEXT

Recent randomized controlled trials (RCTs) examined the role of adding androgen receptor signaling inhibitors (ARSIs), including abiraterone acetate (ABI), apalutamide, darolutamide (DAR), and enzalutamide (ENZ), to docetaxel (DOC) and androgen deprivation therapy (ADT) in patients with metastatic hormone-sensitive prostate cancer (mHSPC).

OBJECTIVE

To analyze the oncologic benefit of triplet combination therapies using ARSI + DOC + ADT, and comparing them with available treatment regimens in patients with mHSPC.

EVIDENCE ACQUISITION

Three databases and meetings abstracts were queried in April 2022 for RCTs analyzing patients treated with first-line combination systemic therapy for mHSPC. The primary interests of measure were overall survival (OS) and progression-free survival (PFS). Subgroup analyses were conducted to assess the differential outcomes in patients with low- and high-volume disease as well as de novo and metachronous metastasis.

EVIDENCE SYNTHESIS

Overall, 11 RCTs were included for meta-analyses and network meta-analyses (NMAs). We found that the triplet combinations outperformed DOC + ADT in terms of OS (pooled hazard ratio [HR]: 0.74, 95% confidence interval [CI]: 0.65-0.84) and PFS (pooled HR: 0.49, 95% CI: 0.42-0.58). There was no statistically significant difference between patients with low- and high-volume disease in terms of an OS benefit from adding an ARSI to DOC +ADT (both HR: 0.79; p = 1). Based on NMAs, triplet therapy also outperformed ARSI + ADT in terms of OS (DAR + DOC + ADT: pooled HR: 0.74, 95% CI: 0.55-0.99) and PFS (ABI + DOC + ADT: HR: 0.68, 95% CI: 0.51-0.91, and ENZ + DOC + ADT: HR: 0.70, 95% CI: 0.53-0.93). An analysis of treatment ranking among de novo mHSPC patients showed that triplet therapy had the highest likelihood of improved OS in patients with high-volume disease; however, doublet therapy using ARSI + ADT had the highest likelihood of improved OS in patients with low-volume disease.

CONCLUSIONS

We found that the triplet combination therapy improves survival endpoints in mHSPC patients compared with currently available doublet treatment regimens. Our findings need to be confirmed in further head-to-head trials with longer follow-up and among various patient populations.

PATIENT SUMMARY

Our study suggests that triplet therapy with androgen receptor signaling inhibitor, docetaxel, androgen deprivation therapy prolongs survival in patients with metastatic hormone-sensitive prostate cancer compared with the current standard doublet therapy.

Systemic Therapy for Metastatic Hormone-Sensitive Prostate Cancer: A Randomized Controlled Trial-Based Network Meta-Analysis

Objective. To compare the effects of different treatment strategies for metastatic hormone-sensitive prostate cancer (mHSPC) using a network meta-analysis. Methods. English databases (PubMed, Embase, and medRxiv) and Chinese databases (Wanfang and CNKI) were searched for randomized controlled trials (RCTs) on the treatment of mHSPC from inception to June 1, 2021. The overall survival (OS) and failure-free survival (FFS) reported by the included studies were extracted from each study for network meta-analysis. Moreover, the priority ranks of the treatment methods were determined. Results. A total of 18 RCTs with 14,682 patients were included in this study. Androgen-deprivation therapy (ADT) + apalutamide (APA) showed the highest probability of improving the OS (96.2%) and FFS (68.0%). In addition, the patients were stratified into ten subgroups as follows: low/high tumor burden (CHAARTED criteria); Gleason score ≤7/≥8; Eastern Cooperative Oncology Group (ECOG) = 0/≥1; with/without prechemotherapy; and cooperative with/without concomitant radiotherapy. For the improvement of OS, the leading treatments were as follows: (1) ADT + enzalutamide (ENZA) (64.1%)/ADT + abiraterone acetate + prednisone (AAP) (54.3%); (2) ADT + ENZA (41.9%)/ADT + APA (39.2%); (3) ADT + ENZA (39.2%)/ADT + APA (32.1%); (4) ADT + radiotherapy (51%)/ADT + ENZA (76.7%); (5) ADT + AAP (51%)/ADT + AAP (60%). Conclusion. Three endocrine therapy drugs, abiraterone, enzalutamide, and APA, exhibited the best effects in improving the OS and FFS in all patients and subgroups; however, APA had the most prominent treatment effects. Therefore, ADT + APA should be applied as the common treatment for patients with HSPC based on objective and clinical conditions. Trial Registration. This meta-analysis has been registered on the PROSPERO website (Trial number: https://www.crd.york.ac.uk/prospero/CRD42020221062).

Abiraterone acetate versus nonsteroidal antiandrogen with androgen deprivation therapy for high-risk metastatic hormone-sensitive prostate cancer

BACKGROUND

Although prostate cancer is a very common form of malignancy in men, the clinical significance of androgen deprivation therapy (ADT) with abiraterone acetate versus the nonsteroidal antiandrogen bicalutamide has not yet been verified in patients with high-risk metastatic hormone-sensitive prostate cancer (mHSPC). The present study was designed to initiate this verification in real-world Japanese clinical practice.

METHODS

We retrospectively analyzed the records of 312 patients with high-risk mHSPC based on LATITUDE criteria and had received ADT with bicalutamide (n = 212) or abiraterone acetate (n = 100) between September 2015 and December 2020. Bicalutamide was given at 80 mg daily and abiraterone was given at 1000 mg daily as four 250-mg tablets plus prednisolone (5-10 mg daily). Overall survival (OS), cancer-specific survival (CSS), and time to castration-resistant prostate cancer (CRPC) were compared. The prognostic factor for time to CRPC was analyzed by Cox proportional hazard model.

RESULTS

Patients in the bicalutamide group were older, and more of them had poor performance status (≧2), than in the abiraterone group. Impaired liver function was noted in 2% of the bicalutamide group and 16% of the abiraterone group (p < 0.001). Median follow-up was 22.5 months for bicalutamide and 17 months for abiraterone (p < 0.001). Two-year OS and CSS for bicalutamide versus abiraterone was 77.8% versus 79.5% (p = 0.793) and 81.1% versus 82.5% (p = 0.698), respectively. Median time to CRPC was significantly longer in the abiraterone group than in the bicalutamide group (NA vs. 13 months, p < 0.001). In multivariate analysis, Gleason score ≧9, high alkaline phosphatase, high lactate dehydrogenase, liver metastasis, and bicalutamide were independent prognostic risk factors for time to CRPC. Abiraterone prolonged the time to CRPC in patients with each of these prognostic factors.

CONCLUSIONS

Despite limitations regarding the time-dependent bias, ADT with abiraterone acetate significantly prolonged the time to CRPC compared to bicalutamide in patients with high-risk mHSPC. However, further study with longer follow-up is needed.

Treatment Strategies for Metastatic Castration-Sensitive Prostate Cancer: From "All-Comers" to "Personalized" Approach

Standard treatment for metastatic castration-sensitive prostate cancer (mCSPC) was androgen-deprivation therapy (ADT) for >7 decades, and this was termed the “all-comers” approach. A remarkable evolution in the treatment of mCSPC has been noted in the previous several years. High-quality clinical trials have shown that the addition of docetaxel or androgen receptor pathway inhibitors, such as abiraterone acetate, enzalutamide, and apalutamide, to ADT improves the overall survival (OS) as compared to ADT alone. The first 2 trials demonstrated the benefits of docetaxel and abiraterone acetate in terms of OS in high-volume and high-risk cancer subgroups, respectively. The later trials indicated that upfront combination therapies were associated with improved OS in all patients, irrespective of tumor volume and risk category. Upfront combination therapies are becoming a standard of care for all patients with mCSPC. However, meta-analyses have failed to show that all upfront combination therapies provide significant survival benefits in all patient subgroups. In the low-volume subgroup, significance was observed only for treatment with enzalutamide and radiation to the prostate. Men with low-volume low-risk cancer who have favorable response to ADT achieve long-term survival with ADT only, and toxicities induced by combination therapies would exceed the benefit for these patients. Treatments should be tailored to each patient because mCSPC has marked diversity in its biological and clinical features. Recent advances in diagnostic and molecular technologies will provide useful prognostic and predictive biomarkers, and the treatment strategy will shift from the “for all-comers” to the “individualized” approach.