Potential Utility of Novel Biomarkers in Active Surveillance of Low-Risk Prostate Cancer

Active Surveillance for Intermediate-Risk Prostate Cancer: Systematic Review and Meta-analysis of Current Protocols and Outcomes

INTRODUCTION

Current guidelines allow active surveillance for intermediate-risk prostate cancer patients but do not provide comprehensive recommendations for selection. We performed a systematic review and meta-analysis of outcomes for active surveillance in intermediate- and low-risk groups.

METHODS

We performed a systematic literature search of intermediate-risk localized prostate cancer patients undergoing active surveillance using 3 literature search engines (Medline, Web of Science, and Scopus) over the past 10 years. The primary outcome was the percentage of patients who remain under surveillance. Secondary outcomes included cancer-specific survival, overall survival, and metastasis-free survival. For articles including both low- and intermediate-risk patients undergoing active surveillance, comparisons between the two groups were made.

RESULTS

The proportion of patients who remained on active surveillance was comparable between the low- and intermediate-risk groups after 10 and 15 years' follow-up (odds ratio [OR], 0.97; 95% confidence interval [CI], 0.83-1.14; and OR, 0.86; 95% CI, 0.65-1.13). Cancer-specific survival was worse in the intermediate-risk group after 10 years (OR, 0.47; 95% CI, 0.31-0.69) and 15 years (OR, 0.34; 95% CI, 0.2-0.58). The overall survival rate showed no statistical difference at 5 years' follow-up (OR, 0.84; 95% CI, 0.45-1.57) but was worse in the intermediate-risk group after 10 years (OR, 0.43; 95% CI, 0.35-0.53). Metastases-free survival did not significantly differ after 5 years (OR, 0.55; 95% CI, 0.2-1.53) and was worse in the intermediate-risk group after 10 years (OR, 0.46; 95% CI, 0.28-0.77).

CONCLUSION

Active surveillance could be offered to patients with intermediate-risk prostate cancer. However, they should be informed of the need for regular monitoring and the possibility of discontinuation as a result of a higher rate of progression. Available data indicate that 5-year survival rates between intermediate- and low-risk patients do not differ; 10-year survival rates are worse. To assess the long-term effectiveness and safety of active surveillance, it is necessary to develop unified algorithms for patient selection and management, and to prospectively conduct studies with long-term surveillance.

A novel predictor of clinical progression in patients on active surveillance for prostate cancer

INTRODUCTION

Active surveillance (AS) is standard of care in low-risk prostate cancer (PCa). This study describes a novel total cancer location (TCLo) density metric and aims to determine its performance in predicting clinical progression (CP) and grade progression (GP).

METHODS

This was a retrospective study of patients on AS after confirmatory biopsy (CBx). We excluded patients with Gleason ≥7 at CBx and <2 years followup. TCLo was the number of locations with positive cores at diagnosis (DBx) and CBx. TCLo density was TCLo/prostate volume (PV). CP was progression to any active treatment while GP occurred if Gleason ≥7 was identified on repeat biopsy or surgical pathology. Independent predictors of time to CP or GP were estimated with Cox regression. Kaplan-Meier analysis compared progression-free survival (PFS) curves between TCLo density groups. Test characteristics of TCLo density were explored with receiver operating characteristic (ROC) curves.

RESULTS

We included 181 patients who had CBx from 2012-2015 and met inclusion criteria. The mean age of patients was 62.58 years (standard deviation [SD] 7.13) and median followup was 60.9 months (interquartile range [IQR] 23.4). A high TCLo density score (>0.05) was independently associated with time to CP (hazard ratio [HR] 4.70; 95% confidence interval [CI] 2.62-8.42; p<0.001) and GP (HR 3.85; 95% CI 1.91-7.73; p<0.001). ROC curves showed TCLo density has greater area under the curve than number of positive cores at CBx in predicting progression.

CONCLUSIONS

TCLo density is able to stratify patients on AS for risk of CP and GP. With further validation, it could be added to the decision-making algorithm in AS for low-risk localized PCa.

Approaches to the discovery of non-invasive urinary biomarkers of prostate cancer

Prostate cancer (PCa) continues to be one of the most common cancers in men worldwide. Prostate specific antigen (PSA) measured in blood has been used for decades as an aid for physicians to detect the presence of prostate cancer. However, the PSA test has limited sensitivity and specificity, leading to unnecessary biopsies, overdiagnosis and overtreatment of patients. For these reasons, there is an urgent need for more accurate PCa biomarkers that can detect PCa with high sensitivity and specificity. Urine is a unique source of potential protein biomarkers that can be measured in a non-invasive way. This review comprehensively summarizes state of the art approaches used in the discovery and validation of urinary biomarkers for PCa. Numerous strategies are currently being used in the discovery of urinary biomarkers for prostate cancer including gel-based separation techniques, mass spectrometry, activity-based proteomic assays and software approaches. Antibody-based approaches remain preferred method for validation of candidate biomarkers with rapidly advancing multiplex immunoassays and MS-based targeted approaches. In the last decade, there has been a dramatic acceleration in the development of new techniques and approaches in the discovery of protein biomarkers for prostate cancer including computational, statistical and data mining methods. Many urinary-based protein biomarkers have been identified and have shown significant promise in initial studies. Examples of these potential biomarkers and the methods utilized in their discovery are also discussed in this review.

Identification of fluorescence in situ hybridization assay markers for prediction of disease progression in prostate cancer patients on active surveillance

BACKGROUND

Prostate Cancer (PCa) is the second most prevalent cancer among U.S. males. In recent decades many men with low risk PCa have been over diagnosed and over treated. Given significant co-morbidities associated with definitive treatments, maximizing patient quality of life while recognizing early signs of aggressive disease is essential. There remains a need to better stratify newly diagnosed men according to the risk of disease progression, identifying, with high sensitivity and specificity, candidates for active surveillance versus intervention therapy. The objective of this study was to select fluorescence in situ hybridization (FISH) panels that differentiate non-progressive from progressive disease in patients with low and intermediate risk PCa.

METHODS

We performed a retrospective case-control study to evaluate FISH biomarkers on specimens from PCa patients with clinically localised disease (T1c-T2c) enrolled in Watchful waiting (WW)/Active Surveillance (AS). The patients were classified into cases (progressed to clinical intervention within 10 years), and controls (did not progress in 10 years). Receiver Operating Characteristic (ROC) curve analysis was performed to identify the best 3-5 probe combinations. FISH parameters were then combined with the clinical parameters ─ National Comprehensive Cancer Network (NNCN) risk categories ─ in the logistic regression model.

RESULTS

Seven combinations of FISH parameters with the highest sensitivity and specificity for discriminating cases from controls were selected based on the ROC curve analysis. In the logistic regression model, these combinations contributed significantly to the prediction of PCa outcome. The combination of NCCN risk categories and FISH was additive to the clinical parameters or FISH alone in the final model, with odds ratios of 5.1 to 7.0 for the likelihood of the FISH-positive patients in the intended population to develop disease progression, as compared to the FISH-negative group.

CONCLUSIONS

Combinations of FISH parameters discriminating progressive from non-progressive PCa were selected based on ROC curve analysis. The combination of clinical parameters and FISH outperformed clinical parameters alone, and was complimentary to clinical parameters in the final model, demonstrating potential utility of multi-colour FISH panels as an auxiliary tool for PCa risk stratification. Further studies with larger cohorts are planned to confirm these findings.

Active Surveillance for Intermediate Risk Prostate Cancer: Survival Outcomes in the Sunnybrook Experience

PURPOSE

To assess the applicability of active surveillance in patients with intermediate risk prostate cancer, we compared the survival outcomes of patients with low risk and intermediate risk disease.

MATERIALS AND METHODS

Active surveillance was offered to all patients with low risk (cT1-T2b and Gleason score 6 and prostate specific antigen 10 ng/ml or less) and select intermediate risk disease (age greater than 70 years with cT2c or prostate specific antigen 15 ng/ml or less, or Gleason score 3+4 or less). Data from November 1995 to May 2013 were extracted from a prospectively collected database. The primary outcome was metastasis-free survival, and secondary outcomes were overall survival, cause specific survival and treatment-free survival.

RESULTS

A total of 213 intermediate risk and 732 low risk cases were identified. Median age was 72 years (IQR 67.3, 76.8) in the intermediate risk cohort and 67 years (IQR 60.6, 71.9) in the low risk group. Median followup was comparable (6.7 years for intermediate risk vs 6.5 years for low risk). Gleason 7 disease comprised 60% of the intermediate risk cohort. The 15-year metastasis-free, overall, cause specific and treatment-free survival rates were inferior in the intermediate risk group (metastasis-free survival HR 3.14, 95% CI 1.51-6.53, p=0.001, 82% for intermediate risk vs 95% for low risk). On further evaluation the estimated 15-year metastasis-free survival for cases of Gleason 6 or less with prostate specific antigen less than 10 ng/ml was 94%, Gleason 6 or less with prostate specific antigen 10 to 20 ng/ml was 94%, Gleason 3+4 with prostate specific antigen 20 ng/ml or less was 84% and Gleason 4+3 with prostate specific antigen 20 ng/ml or less was 63%.

CONCLUSIONS

These data support the use of active surveillance in low risk and intermediate risk cases of Gleason 6 but not Gleason 7 prostate cancer. Multiparametric magnetic resonance imaging and novel biomarkers might be vital in detecting favorable Gleason 7 disease.

Prognostic Value of Protocadherin10 (PCDH10) Methylation in Serum of Prostate Cancer Patients

Background

Prostate cancer is a heterogeneous malignancy with outcome difficult to predict. Currently, there is an urgent need to identify novel biomarkers that can accurately predict patient outcome and improve the treatment strategy. The aim of this study was to investigate the methylation status of PCDH10 in serum of prostate cancer patients and its potential relevance to clinicopathological features and prognosis.

Material/Methods

The methylation status of PCDH10 in serum of 171 primary prostate cancer patients and 65 controls was evaluated by methylation-specific PCR (MSP), after which the relationship between PCDH10 methylation and clinicopathologic features was evaluated. Kaplan-Meier survival analysis and Cox analysis were used to evaluate the correlation between PCDH10 methylation and prognosis.

Results

PCDH10 methylation occurred frequently in serum of prostate cancer patients. Moreover, PCDH10 methylation was significantly associated with higher preoperative PSA level, advanced clinical stage, higher Gleason score, lymph node metastasis, and biochemical recurrence (BCR). In addition, patients with methylated PCDH10 had shorter BCR-free survival and overall survival than patients with unmethylated PCDH10. Univariate and multivariate Cox proportional hazards model analysis indicated that PCDH10 methylation in serum is an independent predictor of worse BCR-free survival and overall survival.

Conclusions

PCDH10 methylation in serum is a potential prognostic biomarker for prostate cancer.