Patterns and Predictors of Early Biochemical Recurrence After Radical Prostatectomy and Adjuvant Radiation Therapy in Men With pT3N0 Prostate Cancer: Implications for Multimodal Therapies

Cost-Effectiveness Modeling of Prostate-Specific Membrane Antigen Positron Emission Tomography with Piflufolastat F 18 for the Initial Diagnosis of Patients with Prostate Cancer in the United States

BACKGROUND AND OBJECTIVES

Piflufolastat F 18 is a novel prostate-specific membrane antigen (PSMA)-targeted positron emission tomography (PET) radiotracer that is superior to standard of care (SOC) imaging for the initial staging of prostate cancer and the detection of biochemical recurrence. As piflufolastat F 18 has been approved in the United States (US) for this indication, this modeling study assessed the cost effectiveness of piflufolastat F 18 versus fluciclovine F-18, gallium68-PSMA-11 (PSMA 11), and SOC imaging (a mix of bone scans, computed tomography, and magnetic resonance imaging) for the diagnosis and staging of prostate cancer from a US healthcare system perspective.

PERSPECTIVE

A US third-party payer perspective was used, which for this population reflects a mix of commercial and Medicare, considering only direct healthcare costs.

SETTING

This study utilized a tertiary healthcare setting.

METHODS

A decision tree was used to map the diagnostic/treatment pathway, consisting of the proportion of patients with local, regional, distant, or no disease; prostate-specific antigen (PSA) ≤ 1.0 or > 1.0; and accuracy of imaging modalities. A Markov model predicted the long-term outcomes of disease progression according to treatment decisions. Inputs to the model were informed by data from the OSPREY and CONDOR clinical trials, public data, and the literature. Treatment mix included active surveillance, radiation therapy, prostatectomy, androgen deprivation therapy (ADT), and radiation therapy + ADT, informed by expert opinion. Outcomes included life-years (LY), quality-adjusted life-years (QALY), and the incremental cost-effectiveness ratio (ICER). All costs were reported in 2021 US dollars, using the US Bureau of Labor Statistics Consumer Price Index. A willingness-to-pay (WTP) threshold of $150,000 was considered cost effective, consistent with the upper range used as the standard for price benchmarks by the Institute for Clinical and Economic Review. The robustness of the base-case results was assessed in deterministic and probabilistic sensitivity analyses.

RESULTS

Over a lifetime horizon, piflufolastat F 18 had the greatest effectiveness in terms of LYs (6.80) and QALYs (5.33); for the comparators, LYs ranged from 6.58 (SOC) to 6.76 (PSMA 11) and QALYs ranged from 5.12 (SOC) and 5.30 (PSMA 11). Piflufolastat F 18 was more cost effective compared with fluciclovine F 18, PSMA 11, and SOC, with ICERs of $21,122, $55,836, and $124,330 per QALY gained, respectively. Piflufolastat F 18 was associated with the greatest net monetary benefit ($627,918) compared with the other options at a WTP threshold of $150,000. The results of the deterministic and probabilistic sensitivity analyses supported the robustness of the base-case results.

CONCLUSIONS

This study suggests that piflufolastat F 18 is a cost-effective diagnostic option for men with prostate cancer in the US, with higher associated LY, QALY, and greater net monetary benefit than fluciclovine F 18, PSMA 11, and SOC imaging.

The Development of a Gleason Score-Related Gene Signature for Predicting the Prognosis of Prostate Cancer

The recurrence of prostate cancer (PCa) is intrinsically linked to increased mortality. The goal of this study was to develop an efficient and reliable prognosis prediction signature for PCa patients. The training cohort was acquired from The Cancer Genome Atlas (TCGA) dataset, while the validation cohort was obtained from the Gene Expression Omnibus (GEO) dataset (GSE70769). To explore the Gleason score (GS)-based prediction signature, we screened the differentially expressed genes (DEGs) between low- and high-GS groups, and then univariate Cox regression survival analysis and multiple Cox analyses were performed sequentially using the training cohort. The testing cohort was used to evaluate and validate the prognostic model's effectiveness, accuracy, and clinical practicability. In addition, the correlation analyses between the risk score and clinical features, as well as immune infiltration, were performed. We constructed and optimized a valid and credible model for predicting the prognosis of PCa recurrence using four GS-associated genes (SFRP4, FEV, COL1A1, SULF1). Furthermore, ROC and Kaplan-Meier analysis revealed a higher predictive efficiency for biochemical recurrence (BCR). The results showed that the risk model was an independent prognostic factor. Moreover, the risk score was associated with clinical features and immune infiltration. Finally, the risk model was validated in a testing cohort. Our data support that the GS-based four-gene signature acts as a novel signature for predicting BCR in PCa patients.

Identification and validation of a signature involving voltage-gated chloride ion channel genes for prediction of prostate cancer recurrence

Voltage-gated chloride ion channels (CLCs) are transmembrane proteins that maintain chloride ion homeostasis in various cells. Accumulating studies indicated CLCs were related to cell growth, proliferation, and cell cycle. Nevertheless, the role of CLCs in prostate cancer (PCa) has not been systematically profiled. The purpose of this study was to investigate the expression profiles and biofunctions of CLCs genes, and construct a novel risk signature to predict biochemical recurrence (BCR) of PCa patients. We identified five differentially expressed CLCs genes in our cohort and then constructed a signature composed of CLCN2 and CLCN6 through Lasso-Cox regression analysis in the training cohort from the Cancer Genome Atlas (TCGA). The testing and entire cohorts from TCGA and the GSE21034 from the Gene Expression Omnibus (GEO) were used as internal and independent external validation datasets. This signature could divide PCa patients into the high and low risk groups with different prognoses, was apparently correlated with clinical features, and was an independent excellent prognostic indicator. Enrichment analysis indicated our signature was primarily concentrated in cellular process and metabolic process. The expression patterns of CLCN2 and CLCN6 were detected in our own cohort based immunohistochemistry staining, and we found CLCN2 and CLCN6 were highly expressed in PCa tissues compared with benign tissues and positively associated with higher Gleason score and shorter BCR-free time. Functional experiments revealed that CLCN2 and CLCN6 downregulation inhibited cell proliferation, colony formation, invasion, and migration, but prolonged cell cycle and promoted apoptosis. Furthermore, Seahorse assay showed that silencing CLCN2 or CLCN6 exerted potential inhibitory effects on energy metabolism in PCa. Collectively, our signature could provide a novel and robust strategy for the prognostic evaluation and improve treatment decision making for PCa patients.

Clinical Evaluation of FOXO1 as a Tumor Suppressor in Prostate Cancer

Objective

Prostate cancer (PCa) is considered the most serious cancer in the world. Nevertheless, the accuracy of current biomarkers, such as pathological staging, Gleason's score, and serum prostate-specific antigen (PSA) levels, is limited. FOXO1 is a key downstream effector of PTEN and a tumor suppressor in PCA, which has been reported extensively. However, the clinical relevance of FOXO1 in PCa remains unclear.

Methods

In this study, we first detected its expression in four public databases to explore the clinical role of FOXO1. Verification of the knockdown effect of FOXO1 siRNA was performed by real-time PCR analysis. Changes in cell viability were assessed using cell counting kit-8 (CCK-8) assays. In addition, we verified the effect of FOXO1 on the PCa cell cycle using a cell cycle assay.

Results

Herein, we found that FOXO1 was significantly downregulated in PCa tissues and was significantly associated with Gleason's score, age, biochemical recurrence (BCR), and lymph node (LN) status, while FOXO1 expression was independent of pathological staging and preoperative PSA levels. The Kaplan-Meier survival analysis showed that PCA patients with high FOXO1 expression were less likely to develop BCR compared with patients with low FOXO1 expression. In terms of function, FOXO1 inhibition significantly promoted the proliferation and cell cycle progression of PCa cells.

Conclusions

In summary, our study suggests that FOXO1 may be one of the prognostic factors that describe the risk of PCa for BCR. These results suggest that FOXO1 may be a therapeutic target for PCa.

A Glycolysis-Related Five-Gene Signature Predicts Biochemical Recurrence-Free Survival in Patients With Prostate Adenocarcinoma

Prostate cancer (PCa) is one of the most frequently diagnosed cancers in males worldwide. Approximately 25% of all patients experience biochemical recurrence (BCR) after radical prostatectomy (RP) and BCR indicates increased risk for metastasis and castration resistance. PCa patients with highly glycolytic tumors have a worse prognosis. Thus, this study aimed to explore glycolysis-based predictive biomarkers for BCR. Expression data and clinical information of PCa samples were retrieved from three publicly available datasets. One from The Cancer Genome Atlas (TCGA) dataset was used as the training cohort, and two from the Gene Expression Omnibus (GEO) dataset (GSE54460 and GSE70769) were used as validation cohorts. Using the training cohort, univariate Cox regression survival analysis, robust likelihood-based survival model, and stepwise multiply Cox analysis were sequentially applied to explore predictive glycolysis-related candidates. A five-gene risk score was then constructed based on the Cox coefficient as the following: (−0.8367*GYS2) + (0.3448*STMN1) + (0.3595*PPFIA4) + (−0.1940*KDELR3) + (0.4779*ABCB6). Receiver operating characteristic curve (ROC) analysis was used to identify the optimal cut-off point, and patients were divided into low risk and high risk groups. Kaplan–Meier analysis revealed that high risk group had significantly shorter BCR free survival time as compared with that in low risk group in training and validation cohorts. In conclusion, our data support the glycolysis-based five-gene signature as a novel and robust signature for predicting BCR of PCa patients.

Risk stratification for disease progression in pT3 prostate cancer after robot-assisted radical prostatectomy

The aim of this study is to identify optimal patients for adjuvant radiation therapy (ART) in pT3 prostate cancer. The role of ART for patients with adverse pathologic features after radical prostatectomy (RP) has been demonstrated, but over- or under-treatment remains a significant concern. Two-hundred and five patients with pT3N0M0 who underwent robot-assisted RP without ART were analyzed. Multivariate Cox proportional regression analyses were used to identify predictors of biochemical recurrence (BCR) and clinical progression (CP). The estimated 5-year BCR-free survival (BCRFS) and CP-free survival (CPFS) were 52.8% and 85.6%, respectively. Preoperative prostate-specifc antigen (PSA) ≥10 ng ml-1 (hazard ratio [HR]: 3.288-6.027; P = 0.003), pathologic Gleason score (pGS) ≥8 (HR: 4.146; P = 0.014), and lymphovascular invasion (LVI) (HR: 2.167; P = 0.026) were associated with BCR. Based on these factors, a risk stratification tool was developed. Patients with no risk factors (PSA <10 ng ml-1 , pGS 6, and absent LVI) showed excellent BCRFS and CPFS at 5 years (91.9% and 100.0%, respectively), but those with two or more risk factors (PSA ≥10 ng ml-1 , pGS ≥8, or present LVI) had poor BCRFS and CPFS (12.1% and 54.6%, respectively). In addition, the multivariate analysis revealed that pathologic stage pT3b (HR: 5.393; P = 0.025) was the only predictor of CP. Our study demonstrated the heterogeneity of oncologic outcomes in patients with pT3 prostate cancer. The proposed risk stratification can be used to identify patients who are at risk for disease progression and may aid in identifying the best patients for ART.

The role of PSMA PET/CT imaging in restaging of prostate cancer patients with low prostate-specific antigen levels

INTRODUCTION

Prostate-specific membrane antigen (PSMA) is increasingly being recognized as a novel target for the PET imaging of prostate cancer (PCa) and Ga-DKFZ-11 (Ga-PSMA) has been suggested as a novel tracer for detection of PCa relapses and metastases. The aim of this study was to evaluate the diagnostic value of PSMA PET/CT in the diagnosis of recurrent PCa with low prostate-specific antigen (PSA) levels.

PATIENTS AND METHODS

We carried out a retrospective analysis of patients who underwent PSMA PET/CT from November 2013 to December 2014 in our department. Among these patients, 50 out of 178 who had increasing PSA levels (<5 ng/ml) and did not have known metastasis were included in this study.

RESULTS

Patients had an average PSA of 1.41 ng/ml. A total of 29 patients (58%) showed at least one positive lesion. PET positivity rates of 31% (n=4), 54% (n=13), and 88% (n=14) were observed in patients with a PSA level of less than 0.2, 0.2-2, and 2-5 ng/ml, respectively. A positive correlation was observed between positivity rate and Gleason scores and blood PSA levels. Verification was performed in 46 patients, with biopsy (n=3) and follow-up, and conventional imaging studies at the time of the PET/CT or during follow-up with a mean period of 10.6±3.3 months and ranged from 3.8 to 16.4 months. According to patient-based analysis of 46 cases, 57% of patients had true positive, 24% of patients had true negative, 2% of patients had false positive, an 18% of patients had false-negative findings. A sensitivity of 76.47% (95% confidence interval: 58.83-89.25%) and a specificity of 91.67% (95% confidence interval: 61.52-99.79%) were found.

CONCLUSION

PET/CT with Ga-PSMA is a valuable tool for assessing recurrence of PCa with a high sensitivity in patients who have PSA levels between 0.2 and 5 ng/ml. In addition, this study suggests that PSMA PET/CT can be used in patients with very low (<0.2 ng/ml) but increasing PSA levels, which, in many cases, may influence further clinical management.

Impact of positive surgical margin on biochemical recurrence following radical prostatectomy in locally advanced prostate cancer

This study aimed to determine the effect of surgical margin positivity on biochemical recurrence (BCR) in patients with locally advanced prostate cancer (PCa) who underwent radical retropubic prostatectomy (RRP). The medical records of all patients with locally advanced PCa that underwent RRP were retrospectively reviewed. Patient demographics, digital rectal examination findings, prostate biopsy Gleason score, prostate volume, pre- and post-treatment prostate-specific antigen (PSA) levels, definitive pathology Gleason score, surgical margin status, seminal vesicle invasion, perineural invasion, absence or presence of BCR, and the time to BCR were analyzed. The study included 130 patients. The final pathologic examination showed that seven (5.4%) patients had T3a disease and 123 (94.6%) had T3b disease. In all, 93 (71.5%) patients had a positive surgical margin [SM(+)], whereas 37 (28.5%) patients had a negative surgical margin [SM(-)]. Among the seven patients with pT3a disease, four (57.1%) had SM(+), whereas 89 (72.4%) of the 123 patients with pT3b disease had SM(-). BCR occurred in 11.8% (11 of 93) of patients with SM(+) and in 45.9% (17 of 37) of those with SM(-) (p < 0.001). Multivariate logistic regression analysis showed that SM(+) was the only significant predictor of BCR following RRP (relative risk, 0.163; 95% confidence interval (0.062-0.433); p < 0.001). SM(+) in RRP specimens is not always indicative of BCR in patients with locally advanced PCa. RRP should be considered an effective treatment choice for selected patients with locally advanced PCa, despite the associated high SM(+) rate.

Evaluation of PSMA PET/CT imaging using a 68Ga-HBED-CC ligand in patients with prostate cancer and the value of early pelvic imaging

PURPOSE

The aim of the study was to evaluate the diagnostic value of the prostate-specific membrane antigen (PSMA) ligand (68)Ga-HBED-CC (PSMA PET/CT) in patients with prostate cancer and evaluate the value of early imaging of the pelvis.

MATERIALS AND METHODS

The files of 28 patients were retrospectively evaluated. All patients had a histopatological confirmation of prostate cancer. PSMA PET/CT images were obtained at 5 and 60 min after injection from all patients.

RESULTS

Intense pathologic radiotracer uptake was observed in 23 patients (77%) at the site of primary tumour. Lymph node metastases were detected in 10 patients (36%) and bone metastases were detected in seven patients (25%). Bone scan (n=25) results revealed metastatic bone lesions in four patients, equivocal results in nine patients and normal results in 12 patients. PSMA PET/CT confirmed bone metastases in all four patients. Pathologic radiotracer uptake in PSMA PET/CT scans was observed only in one patient among those who had equivocal bone scans. PSMA PET/CT showed additional bone lesions in two patients who had a normal bone scan. When we compared early and late pelvic images we found no difference in the number of lesions detected. The maximum standardized uptake value (SUV(max)) for primary tumour, lymph nodes and bone metastases was significantly higher in late images.

CONCLUSION

PSMA PET/CT imaging seems to be a valuable imaging modality for evaluation of primary prostate cancer and it seems to have potential for the detection of lymph node and bone metastases. Early images 5 min p.i. can help to better distinguish between urinary bladder (before tracer accumulation occurs) and tumour lesions.

Models of assessment of comparative outcomes of robot-assisted surgery: best evidence regarding the superiority or inferiority of robot-assisted radical prostatectomy

The widespread dissemination of robot-assisted radical prostatectomy (RARP) occurred despite the absence of high-level evidence supporting its safety and efficacy in patients with clinically localized prostate cancer. This study aims at systematically evaluating the models adopted in scientific reports assessing the comparative effectiveness of RARP versus open radical prostatectomy (ORP). Although several retrospective observational studies have assessed the comparative effectiveness of RARP and ORP, currently no published randomized data are available to comprehensively evaluate this issue. Furthermore, well-designed prospective investigations are needed to ultimately assess the benefits of RARP compared with other treatment modalities in patients with clinically localized prostate cancer.