Predictive Models for Assessing Patients' Response to Treatment in Metastatic Prostate Cancer: A Systematic Review

Background and objective

The treatment landscape of metastatic prostate cancer (mPCa) has evolved significantly over the past two decades. Despite this, the optimal therapy for patients with mPCa has not been determined. This systematic review identifies available predictive models that assess mPCa patients' response to treatment.

Methods

We critically reviewed MEDLINE and CENTRAL in December 2022 according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses statement. Only quantitative studies in English were included with no time restrictions. The quality of the included studies was assessed using the PROBAST tool. Data were extracted following the Checklist for Critical Appraisal and Data Extraction for Systematic Reviews criteria.

Key findings and limitations

The search identified 616 citations, of which 15 studies were included in our review. Nine of the included studies were validated internally or externally. Only one study had a low risk of bias and a low risk concerning applicability. Many studies failed to detail model performance adequately, resulting in a high risk of bias. Where reported, the models indicated good or excellent performance.

Conclusions and clinical implications

Most of the identified predictive models require additional evaluation and validation in properly designed studies before these can be implemented in clinical practice to assist with treatment decision-making for men with mPCa.

Patient summary

In this review, we evaluate studies that predict which treatments will work best for which metastatic prostate cancer patients. We found that existing studies need further improvement before these can be used by health care professionals.

Oral chemotherapeutic agents in metastatic hormone-sensitive prostate cancer: A network meta-analysis of randomized controlled trials

Background

Multiple oral chemotherapeutic agents for metastatic hormone-sensitive prostate cancer (mHSPC) have been developed for conjugated use with conventional androgen deprivation therapy (ADT). Several randomized controlled trials (RCTs) report significant benefits in mHSPC patients. Therefore, we compared overall survival (OS) and progression-free survival (PFS) benefits among considerable mHSPC oral chemotherapeutic agents.

Materials and methods

We investigated mHSPC treatment efficacy through a systematic RCT-trial literature review (PubMed, Embase, Web of Science, the Cochrane Library, and Scopus). Two reviewers independently screened, extracted data, and assessed bias risk in duplicate.

Results

We identified 18 RCTs (n = 13,509). Concerning OS, ADT + abiraterone, ADT + abiraterone + docetaxel, ADT + apalutamide, ADT + bicalutamide, ADT + darolutamide + docetaxel, ADT + enzalutamide, ADT + orteronel, and ADT + rezvilutamide were more effective than the standard of care (SOC). Comparing PFS, most treatments were more effective than SOC, excluding ADT + bicalutamide, nilutamide, flutamide, ADT + bicalutamide + palbociclib, and ADT + nilutamide. ADT + docetaxel with androgen receptor targeted agent (ARTA) triplet therapy was not among the top three treatments determined through ranking analysis.

Conclusions

Novel oral chemotherapeutic agent combination therapies must replace current ADT monotherapy and ADT + docetaxel SOC. Even so, ADT + docetaxel with ARTA triplet therapy still is not the best mHSPC treatment and requires further study.

Chromosomal Instability in Cell-free DNA as a Prognostic Biomarker of Metastatic Hormone-sensitive Prostate Cancer Treated with Androgen Deprivation Therapy

BACKGROUND

Although patients with metastatic hormone-sensitive prostate cancer (mHSPC) undergo androgen deprivation therapy (ADT), the disease can progress to metastatic castration-resistant prostate cancer (mCRPC). There are no reliable biomarkers for predicting this progression. Chromosomal instability resulting in copy number alterations (CNAs) is characteristically observed in patients with various cancers.

OBJECTIVE

To investigate the role of chromosomal instability in patients with mHSPC.

DESIGN, SETTING, AND PARTICIPANTS

This prospective study analyzed cell-free DNA (cfDNA) in pretreatment plasma samples from 75 patients with elevated prostate-specific antigen. Low-depth whole-genome sequencing of cfDNA was performed to identify CNAs.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

The I score (sum of the product of the absolute Z score and the corresponding chromosome length) was used as a measure of chromosomal instability. Kaplan-Meier and Cox proportional-hazard regression analyses were performed to evaluate the association between the I score and time to progression (TTP) and the prognostic value of chromosomal instability in predicting castration resistance, respectively.

RESULTS AND LIMITATIONS

Of 22 patients with a positive I score, 86.4% (19/22) had metastatic prostate cancer. Of these 19 cases, 94.7% (18/19) were mHSPC, which was high-volume mHSPC in 83.3% (15/18). None of the patients with localized prostate cancer had a positive I score. TTP in patients with mHSPC was significantly shorter in the positive than in the negative I-score group (16.4 vs 36.9 mo; p = 0.001). Only the I score could independently predict mCRPC development (hazard ratio 10.315, 95% confidence interval 1.141-93.208; p = 0.038).

CONCLUSIONS

The I score could be a biomarker for ADT response and progression to mCRPC in patients with mHSPC.

PATIENT SUMMARY

We investigated whether genetic changes in cell-free DNA can predict outcomes for patients with metastatic prostate cancer that still responds to hormone therapy. We found that chromosomal instability could be a potential predictor of the development of metastatic castration-resistant prostate cancer.

Prognostic significance of risk stratification in CHAARTED and LATITUDE studies among Japanese men with castration-resistant prostate cancer

Background

The CHAARTED and LATITUDE trials demonstrated a survival benefit of docetaxel and abiraterone for hormone-sensitive prostate cancer. In this study, we examined the impact of the risk stratification criteria used in the CHAARTED and LATITUDE trials on the prognosis of castration-resistant prostate cancer (CRPC). We also tested whether these risk stratification criteria could help in selecting effective initial treatment for CRPC.

Method

Japanese patients with CRPC who were treated with docetaxel or androgen receptor pathway inhibitors such as abiraterone acetate or enzalutamide between 2014 and 2018 were included in this study. Clinicopathological factors, progression-free survival, and overall survival were investigated.

Results

Of 215 patients, 110 men (51.2%) and 93 men (43.3%) were grouped as high volume by CHAARTED criteria and high risk by LATITUDE criteria, respectively. Median progression-free survival was 10.3/4.5 months (P < 0.0001) for low/high volume (CHAARTED criteria) and 9.9/4.8 months (P = 0.0032) for low/high risk (LATITUDE criteria). The median overall survival was 44.8/17.4 months (P < 0.0001) for low/high volume (CHAARTED criteria) and 37.4/17.4 months (P = 0.0011) for low/high risk (LATITUDE criteria). The prognostic impact of CHAARTED and LATITUDE criteria was comparable between androgen receptor pathway inhibitors and docetaxel as first-line treatment for CRPC.

Conclusion

The CHAARTED and LATITUDE criteria were prognostic, but not useful to discriminate the therapeutic outcome between androgen receptor pathway inhibitors and docetaxel for CRPC.

The curative effect of androgen deprivation therapy alone is insufficient in high-risk prostate cancer

To compare the outcomes of patients with high-risk prostate cancer treated by primary radical prostatectomy (RP) and primary androgen deprivation therapy (ADT).The study included patients with high-risk or very high-risk prostate cancer. Patients treated with definitive radiation therapy and those with clinical N1 and M1 disease were excluded. The RP group was divided into sub-cohorts of patients treated with ADT and those who received ADT after biochemical recurrence post-RP. Cancer-specific survival (CSS) and overall survival (OS) were analyzed using the Kaplan-Meier method and the Cox proportional hazards model.The study analyzed 859 patients divided into the RP group (n = 654) and ADT group (n = 205). Castration-resistant prostate cancer was detected in 23 (3.5%) patients in the RP group and 43 (21.0%) patients in the ADT group. Mortality cases included 63 (9.6%) patients in the RP group and 91 (44.4%) patients in the ADT group. CSS (P = .0002) and OS (P < .0001) were significantly higher in the RP group than in the ADT group. In the sub-cohort, CSS did not differ significantly between the RP and ADT groups, whereas OS was significantly higher in the RP group than in the ADT group (P < .0001). In the multivariate analysis, primary ADT increased CSS (hazard ratio, 2.068; P = .0498) and OS (hazard ratio, 3.218; P < .0001) compared with RP.In clinically localized high-risk prostate cancer patients, primary RP was associated with better CSS and OS than primary ADT. Comprehensive counseling in this cohort of patients will help the selection of treatment.

Age-specific survival in prostate cancer using machine learning

Purpose

The incidence of prostate cancer is increasing from the past few decades. Various studies have tried to determine the survival of patients, but metastatic prostate cancer is still not extensively explored. The survival rate of metastatic prostate cancer is very less compared to the earlier stages. The study aims to investigate the survivability of metastatic prostate cancer based on the age group to which a patient belongs, and the difference between the significance of the attributes for different age groups.

Design/methodology/approach

Data of metastatic prostate cancer patients was collected from a cancer hospital in India. Two predictive models were built for the analysis-one for the complete dataset, and the other for separate age groups. Machine learning was applied to both the models and their accuracies were compared for the analysis. Also, information gain for each model has been evaluated to determine the significant predictors for each age group.

Findings

The ensemble approach gave the best results of 81.4% for the complete dataset, and thus was used for the age-specific models. The results concluded that the age-specific model had the direct average accuracy of 83.74% and weighted average accuracy of 79.9%, with the highest accuracy levels for age less than 60.

Originality/value

The study developed a model that predicts the survival of metastatic prostate cancer based on age. The study will be able to assist the clinicians in determining the best course of treatment for each patient based on ECOG, age and comorbidities.

Sea cucumber extract TBL-12 inhibits the proliferation, migration, and invasion of human prostate cancer cells through the p38 mitogen-activated protein kinase and intrinsic caspase apoptosis pathway

BACKGROUND

Sea cucumber is a kind of nutritious echinoderm that has multiple biological activities, including antioxidant, antibacterial, and antitumor activities. However, there is no extensive study on the antitumor effect of sea cucumber extract on prostate cancer (PCa). TBL-12 is a new sea cucumber extract. In this study, we investigated the in vivo anti-PCa effect of TBL-12 and its in vitro effects on the proliferation, apoptosis, migration, and invasion of the human PCa cell lines LNCaP, 22RV1, PC-3, and DU145, and evaluated its possible mechanisms.

METHODS

Cell proliferation was analyzed by cell counting kit-8 and colony formation assays. Scratch migration assay and transwell invasiveness assay were used to observe TBL-12 effect on the migration and invasion of PCa cells. Matrix metalloproteinase 2 (MMP-2) and MMP-9 expression and enzymatic activity was determined by Western blot analysis, quantitative reverse-transcription polymerase chain reaction, and gelatin zymography. Apoptosis level was detected by flow cytometry analysis. Western blot analysis was used to analyze p38 mitogen-activated protein kinase (MAPK) and apoptosis pathways. Angiogenic array analysis was used to explore autocrine and paracrine growth factors in PCa cell lines. Xenograft tumor model was built to observe the in vivo anticancer effect.

RESULTS

TBL-12 could significantly inhibit tumor growth in xenograft PCa mice in vivo, and dramatically inhibit the proliferation, colony formation, migration, and invasiveness of PCa cells in vitro (P < 0.05 and P < 0.001). The expression and enzyme activity of MMP-2 and MMP-9 were significantly suppressed by TBL-12 ( P < 0.01), and decreased phosphorylation level of p38 in PCa cells was detected ( P < 0.001). Furthermore, TBL-12 could reinforce the MMP-2/MMP-9 inhibitory effect of SB203580, a specific inhibitor of the p38 MAPK pathway ( P < 0.05). Besides, TBL-12 could induce the apoptosis of PCa cells by activating caspase-9, caspase-7, and poly(ADP-ribose) polymerase and suppressing survivin, and inhibit the secretion of angiogenin, angiopoietin-2, and vascular endothelial growth factor in PCa cells.

CONCLUSIONS

Sea cucumber extract TBL-12 could suppress the proliferation and metastasis of human PCa cells by inhibiting MMP-2 and MMP-9 via blocking the p38 MAPK pathway, inducing apoptosis through intrinsic caspase apoptosis pathway and inhibiting the secretion of angiogenic factors. Our findings may be of importance and significance for the research and clinical applications of sea cucumber extract in PCa treatment.