Cumulative probability of prostate cancer detection in biopsy according to free/total PSA ratio in men with total PSA levels of 2.1-10.0 ng/ml at population screening

Peripheral zone PSA density: a predominant variable to improve prostate cancer detection efficiency in men with PSA higher than 4 ng ml-1

To improve the diagnostic efficiency of prostate cancer (PCa) and reduce unnecessary biopsies, we defined and analyzed the diagnostic efficiency of peripheral zone prostate-specific antigen (PSA) density (PZ-PSAD). Patients who underwent systematic 12-core prostate biopsies in Shanghai General Hospital (Shanghai, China) between January 2012 and January 2018 were retrospectively identified (n = 529). Another group of patients with benign prostatic hyperplasia (n = 100) were randomly preselected to obtain the PSA density of the non-PCa cohort (N-PSAD). Prostate volumes and transition zone volumes were measured using multiparameter magnetic resonance imaging (mpMRI) and were combined with PSA and N-PSAD to obtain the PZ-PSAD from a specific algorithm. Receiver operating characteristic (ROC) curve analysis was used to assess the PCa detection efficiency in patients stratified by PSA level, and the area under the ROC curve (AUC) of PZ-PSAD was higher than that of PSA, PSA density (PSAD), and transition zone PSA density (TZ-PSAD). PZ-PSAD could amend the diagnosis for more than half of the patients with inaccurate transrectal ultrasonography (TRUS) and mpMRI results. When TRUS and mpMRI findings were ambiguous to predict PCa (PIRADS score ≤3), PZ-PSAD could increase the positive rate of biopsy from 21.7% to 54.7%, and help 63.8% (150/235) of patients avoid unnecessary prostate biopsy. In patients whose PSA was 4.0-10.0 ng ml-1, 10.1-20.0 ng ml-1, and >20.0 ng ml-1, the ideal PZ-PSAD cut-off value for predicting clinically significant PCa was 0.019 ng ml-2, 0.297 ng ml-2, and 1.180 ng ml-2, respectively (sensitivity >90%). Compared with PSA, PSAD, and TZ-PSAD, the efficiency of PZ-PSAD for predicting PCa is the highest, leading to fewer missed diagnoses and unnecessary biopsies.

Five Circular RNAs in Metabolism Pathways Related to Prostate Cancer

Prostate cancer (PCa) is the most common malignant tumor in men, and its incidence increases with age. Serum prostate-specific antigen and tissue biopsy remain the standard for diagnosis of suspected PCa. However, these clinical indicators may lead to aggressive overtreatment in patients who have been treated sufficiently with active surveillance. Circular RNAs (circRNAs) have been recently recognized as a new type of regulatory RNA that is not easily degraded by RNases and other exonucleases because of their covalent closed cyclic structure. Thus, we utilized high-throughput sequencing data and bioinformatics analysis to identify specifically expressed circRNAs in PCa and filtered out five specific circRNAs for further analysis—hsa_circ_0006410, hsa_circ_0003970, hsa_circ_0006754, hsa_circ_0005848, and a novel circRNA, hsa_circ_AKAP7. We constructed a circRNA-miRNA regulatory network and used miRNA and differentially expressed mRNA interactions to predict the function of the selected circRNAs. Furthermore, survival analysis of their cognate genes and PCR verification of these five circRNAs revealed that they are closely related to well-known PCa pathways such as the MAPK signaling pathway, P53 pathway, androgen receptor signaling pathway, cell cycle, hormone-mediated signaling pathway, and cellular lipid metabolic process. By understanding the related metabolism of circRNAs, these circRNAs could act as metabolic biomarkers, and monitoring their levels could help diagnose PCa. Meanwhile, the exact regulatory mechanism for AR-related regulation in PCa is still unclear. The circRNAs we found can provide new solutions for research in this field.

Measurement of serum prostate cancer markers using a nanopore thin film based optofluidic chip

Currently used cancer marker for prostate adenocarcinoma (PC), serum prostate-specific antigen (PSA), greatly overestimates PC population. Patients with high PSA levels have to undergo unnecessary but physically painful and expensive procedure such as prostate biopsies repeatedly. The reliability of PC test can be greatly increased by finding a protein that is secreted selectively by malignant, but not normal, prostate cells. A recently discovered novel protein, referred as neuroendocrine marker (NEM), is secreted only by malignant prostate cells and released in blood circulation. Although NEM seems to be significantly more reliable based on the data obtained from a limited cohort, currently available NEM ELISA is not suitable for undertaking a large study. Therefore, the goal of the present study was to develop an alternative, label-free assay system that can reliably measure NEM and PSA in patient samples. Herein an optofluidic chip that can reliably detect PSA as well as NEM in patient samples has been developed. The optofluidic chip, which consists of arrayed nanopore-based sensors fabricated from anodic aluminum oxide (AAO) thin film, offers improved sensitivity upon the optimization of the concentration of the detector antibodies immobilized on the sensor surface. The results demonstrate that the chip is reliable, extremely sensitive and requires just 1 µl of patient serum (or even less) to measure PSA and NEM even in a non-cancer individual. Compared with the traditional ELISA for PSA, the nanopore-based sensor assay is 50-100 fold more sensitive, and offers many advantages such as elimination of labeled antigen, need for sophisticated equipment and highly trained individuals. These advantages, along with the low cost, should make the technology suitable for point-of-care application to screen elderly male populations for PC and to monitor the progress of patients undergoing PC treatment.

Prostate-specific antigen-based population screening for prostate cancer: current status in Japan and future perspective in Asia

In Western countries, clinical trials on prostate cancer screening demonstrated a limited benefit for patient survival. In the Asia-Pacific region, including Japan, the rate of prostate-specific antigen (PSA) testing remains very low compared with Western countries, and the benefits of population-based screening remain unclear. This review describes the current status of population screening and diagnosis for prostate cancer in Japan and discusses the efficacy of population screening for the Asian population. Since the 1990s, screening systems have been administered by each municipal government in Japan, and decreases in the prostate cancer mortality rate are expected in some regions where the exposure rate to PSA screening has increased markedly. A population-based screening cohort revealed that the proportion of metastatic disease in cancer detected by screening gradually decreased according to the increased exposure rate, and a decreasing trend in the proportion of cancer with high serum PSA levels after population screening was started. The prognosis of the prostate cancer detected by population screening was demonstrated to be more favorable than those diagnosed outside of the population screening. Recent results in screening cohorts demonstrated the efficacy of PSA. These recent evidences regarding population-based screening in Japan may contribute to establishing the optimal prostate cancer screening system in Asian individuals.

Biomarkers for evaluation of prostate cancer prognosis

Prostate cancer, with a lifetime prevalence of one in six men, is the second cause of malignancy-related death and the most prevalent cancer in men in many countries. Nowadays, prostate cancer diagnosis is often based on the use of biomarkers, especially prostate-specific antigen (PSA) which can result in enhanced detection at earlier stage and decreasing in the number of metastatic patients. However, because of the low specificity of PSA, unnecessary biopsies and mistaken diagnoses frequently occur. Prostate cancer has various features so prognosis following diagnosis is greatly variable. There is a requirement for new prognostic biomarkers, particularly to differentiate between inactive and aggressive forms of disease, to improve clinical management of prostate cancer. Research continues into finding additional markers that may allow this goal to be attained. We here selected a group of candidate biomarkers including PSA, PSA velocity, percentage free PSA, TGFβ1, AMACR, chromogranin A, IL-6, IGFBPs, PSCA, biomarkers related to cell cycle regulation, apoptosis, PTEN, androgen receptor, cellular adhesion and angiogenesis, and also prognostic biomarkers with Genomic tests for discussion. This provides an outline of biomarkers that are presently of prognostic interest in prostate cancer investigation.

The relationship between prostate-specific antigen and TNM classification or Gleason score in prostate cancer patients with low prostate-specific antigen levels

BACKGROUND

Prostate-specific antigen (PSA) is a useful biomarker for risk classification in patients with prostate cancer. However, it is unclear whether a correlation exists between low PSA levels (<10 ng/ml) at diagnosis and prognosis.

METHODS

Of the 642 Japanese patients who underwent prostate biopsy and were diagnosed with prostate cancer at Kanazawa University Hospital from 2000 to 2010, 406 patients with a PSA level <20 ng/ml were retrospectively reviewed.

RESULTS

PSA levels in 275 (68%) patients were <10 ng/ml. Although the percentage of Gleason score 8-10 in patients with a PSA level of <3.5 ng/ml was higher than that in patients with a PSA level between 3.5 and 10 ng/ml, it was not statistically significant. On the other hand, the percentage of higher stage (T3 and T4) patients with a PSA level <3.5 ng/ml was significantly greater than that in patients with a PSA level between 3.5 and 10 ng/ml (P < 0.0001). The percentage of metastases (N1 and M1) in patients with a PSA level <3.5 ng/ml was also significantly higher than that in patients with a PSA level between 3.5 and 10 ng/ml (P = 0.0112).

CONCLUSIONS

Patients with prostate cancer with a PSA level <3.5 ng/ml at diagnosis had a more advanced stage of cancer compared with those with a PSA level between 3.5 and 10 ng/ml. Therefore, risk classification using PSA levels at diagnosis may need to take into consideration this specific PSA range in order to better predict survival.

Differences among men on active surveillance for very low-risk prostate cancer detected through population-based versus opportunistic prostate-specific antigen-screening

INTRODUCTION

Very low-risk prostate cancer (PCa) is being increasingly managed by active surveillance (AS). Our aim was to assess the influence of the origin of diagnosis on PCa characteristics and treatment rates among men with very low-risk PCa in our prospective AS cohort.

METHODS

Overall, 191 men with very low-risk PCa fulfilling Epstein-criteria underwent protocol-based AS. These men originated either from the prospective population-based screening program (P-AS) or were diagnosed by opportunistic screening (O-AS).

RESULTS

Overall, n = 86 (45.0%) originated from the P-AS group, whereas n = 105 (55.0%) from the O-AS group. On univariate Cox regression analysis, age (HR 0.96, 95% CI 0.92-1.00; p = 0.05), origin of diagnosis (HR 0.72, 95% CI 0.41-1.28; p = 0.001), number of positive cores (HR 2.15, 95% CI 1.18-3.90; p = 0.01) and maximum core involvement (HR 1.03, 95% CI 0.99-1.05; p = 0.05) were predictors for treatment necessity. On multivariate analysis, age (HR 0.95, 95% CI 0.89-0.99; p = 0.05), number of positive cores (HR 2.07, 95% CI 1.10-3.88; p = 0.02), maximum core involvement (HR 1.03, 95% CI 1.00-1.06; p = 0.04) but not origin of diagnosis were independent predictors for treatment necessity. Four men developed biochemical recurrence (all from O-AS group [p = 0.05]).

CONCLUSION

The origin of PCa diagnosis in men undergoing AS had no influence on disease progression and treatment necessity.

Diagnostic Role of Serum Free-to-Total Prostate Specific Antigen (PSA) Ratio in Prostate Cancer with Serum Total Concentration of PSA below 4 ng/mL

PURPOSE

To examine the effectiveness of serum free-to-total prostate specific antigen ratio (%fPSA) for the detection of prostate cancer (PCa) in men with different serum total PSA (tPSA) categories.

MATERIALS AND METHODS

From January 2010 to December 2013, a total of 225 patients with lower urinary tract symptoms (LUTS) underwent tPSA and %fPSA measurements. Histological examination with calculation of Gleason score and whole body bone scans were performed in identified cases of PCa.

RESULTS

PCa was diagnosed in 44 (19.6%) patients and the remaining 181 patients had benign prostate disease. PCa was detected in 5 (23.8%), 13 (8.7%) and 26 (47.3%) cases with tPSA level ranges≤4 ng/ml, 4 to 10 ng/ml and >10 ng/ml, respectively. The average Gleason score was 7.2±0.2. Some 6 (13.6%) out of 44 PCa patients had bone metastases. The sensitivity was 80% and specificity was 81.3% at the cut-off %fPSA of 15% in PCa patients with a tPSA level below 4 ng/ mL. A lower %fPSA was associated with PCa patients with Gleason score≥7 than those with Gleason score≤6 (11.7±0.98 vs. 16.5±2.25%, P=0.029). No obvious relation of %fPSA to the incidence of bone metastasis was apparent in this study.

CONCLUSIONS

The clinical application of %fPSA could help to discriminate PCa from benign prostate disease in men with a tPSA concentration below 4 ng/mL.

Age-specific reference range of prostate-specific antigen and prostate cancer detection in population-based screening cohort in Japan: verification of Japanese Urological Association Guideline for prostate cancer

OBJECTIVES

To investigate the age-specific reference range of prostate-specific antigen and clinical characteristics of screening-detected cancer in prostate-specific antigen-based screening, and to verify the age-specific prostate-specific antigen cut-offs in the Japanese Urological Association Guidelines.

METHODS

Prostate-specific antigen distributions were estimated in a total of 69,028 screening tests according to the age of the participants in population screening from 2000 to 2013. The age-specific reference range of prostate-specific antigen for detection of cancer was investigated by analyzing the receiver operating characteristic curves. Furthermore, the clinicopathological features of screening-detected cancer with serum prostate-specific antigen levels below the age-specific prostate-specific antigen cut-off in the Japanese Urological Association Guidelines were also investigated.

RESULTS

Of all 69,028 screens, 2053 prostate biopsies (2.97%) were carried out and 549 cases of cancer (0.79%) were diagnosed. The 95th percentiles in all participants aged 54-59, 60-64, 65-69 and 70-75 years old were 2.90, 3.60, 4.10, and 4.70 ng/mL, respectively. The optimal prostate-specific antigen cut-offs for cancer detection determined from the receiver operating characteristic curves were 2.3 and 2.6 for the age ranges 54-69 and 70-75 years, respectively. These values were lower than the age-specific cut-offs in the Japanese Urological Association Guidelines. Of all 137 patients with prostate-specific antigen levels below the age-specific cut-offs in the Japanese Urological Association Guidelines, 80 (58.4%) had unfavorable clinicopathological features as active surveillance criteria.

CONCLUSIONS

The age-specific reference range of prostate-specific antigen might be lower than that recommended in the Japanese Urological Association Guidelines. An individualized and natural history-adjusted screening system should be established for screening participants with low prostate-specific antigen level.