Active Surveillance of Prostate Cancer: Use, Outcomes, Imaging, and Diagnostic Tools

Low-risk prostate lesions: An evidence review to inform discussion on losing the "cancer" label

BACKGROUND

Active surveillance (AS) mitigates harms from overtreatment of low-risk prostate lesions. Recalibration of diagnostic thresholds to redefine which prostate lesions are considered "cancer" and/or adopting alternative diagnostic labels could increase AS uptake and continuation.

METHODS

We searched PubMed and EMBASE to October 2021 for evidence on: (1) clinical outcomes of AS, (2) subclinical prostate cancer at autopsy, (3) reproducibility of histopathological diagnosis, and (4) diagnostic drift. Evidence is presented via narrative synthesis.

RESULTS

AS: one systematic review (13 studies) of men undergoing AS found that prostate cancer-specific mortality was 0%-6% at 15 years. There was eventual termination of AS and conversion to treatment in 45%-66% of men. Four additional cohort studies reported very low rates of metastasis (0%-2.1%) and prostate cancer-specific mortality (0%-0.1%) over follow-up to 15 years. Overall, AS was terminated without medical indication in 1%-9% of men. Subclinical reservoir: 1 systematic review (29 studies) estimated that the subclinical cancer prevalence was 5% at <30 years, and increased nonlinearly to 59% by >79 years. Four additional autopsy studies (mean age: 54-72 years) reported prevalences of 12%-43%. Reproducibility: 1 recent well-conducted study found high reproducibility for low-risk prostate cancer diagnosis, but this was more variable in 7 other studies. Diagnostic drift: 4 studies provided consistent evidence of diagnostic drift, with the most recent (published 2020) reporting that 66% of cases were upgraded and 3% were downgraded when using contemporary diagnostic criteria compared to original diagnoses (1985-1995).

CONCLUSIONS

Evidence collated may inform discussion of diagnostic changes for low-risk prostate lesions.

Gleason pattern 4 with cribriform morphology on biopsy is associated with adverse clinicopathological findings in a prospective radical prostatectomy cohort

The prognostic significance of the Gleason grading system has been well established. However, individual Gleason patterns comprise heterogeneous morphologies which might add additional prognostic information. Recent evidence suggests that Gleason pattern 4 with cribriform growth pattern is associated with an adverse prognosis. To determine the association between cribriform pattern on biopsies and pathological findings on subsequent prostatectomies, we evaluated the presence of cribriform architecture in a prospective cohort of 367 men from 2014 to 2018 treated at a single institution. Cribriform architecture was present in 63.5% of all biopsies and was correlated with the overall extent of Gleason pattern 4. In addition, cribriform morphology on biopsy showed a statistically significant association with higher Gleason grade and increased pathological stage and nodal metastasis. In a subset analysis of cases with Grade Group 2 (Gleason score 3 + 4, n = 208), these associations did not reach statistical significance, but the presence of cribriform growth in this subgroup showed a trend toward increased upgrading to Grade Group 5 (Gleason score 9/10) (1 [0.5%] vs. 5 [2.4%], P = 0.06). This large prospective study comparing biopsy and prostatectomy finding of cribriform architecture demonstrates that cribriform pattern 4 is associated with adverse prognostic features and highlights the relevance for recognizing specific morphologies with distinct biological and clinical features.

Green tea extract for prevention of prostate cancer progression in patients on active surveillance

Background

Active surveillance (AS) has evolved as a management strategy for men with low grade prostate cancer (PCa). However, these patients report anxiety, doubts about the possible progression of the disease as well as higher decisional conflict regarding selection of active surveillance, and have been reported to ultimately opt for treatment without any major change in tumor characteristics. Currently, there is a paucity of research that systematically examines alternate strategies for this target population.

Methods

We conducted a review the evidence from epidemiological, in vitro, preclinical and early phase trials that have evaluated green tea catechins (GTC) for secondary chemoprevention of prostate cancer, focused on men opting for active surveillanceof low grade PCa.

Results

Results of our review of the in vitro, preclinical and phase I-II trials, demonstrates that green tea catechins (GTC) can modulate several relevant intermediate biological intermediate endpoint biomarkers implicated in prostate carcinogenesis as well as clinical progression of PCa, without major side effects.

Discussion

Although clinical trials using GTC have been evaluated in early phase trials in men diagnosed with High-Grade Prostatic Intraepithelial Neoplasia, Atypical Small Acinar Proliferation and in men with localized disease before prostatectomy, the effect of GTC on biological and clinical biomarkers implicated in prostate cancer progression have not been evaluated in this patient population.

Conclusion

Results of these studies promise to provide a strategy for secondary chemoprevention, reduce morbidities due to overtreatment and improve quality of life in men diagnosed with low-grade PCa.

[Multiparametric MRI of the prostate : Important radiological findings for urologists]

CLINICAL/METHODICAL ISSUE

High prevalence of prostate cancer with multifocality and biological heterogeneity. Insufficient conventional urological diagnostics. Discrimination between significant and insignificant cancer needed.

STANDARD DIAGNOSTIC METHODS

Digital rectal examination, prostate-specific antigen (PSA) serum level, systematic transrectal ultrasound (TRUS)-guided prostate biopsy.

METHODICAL INNOVATIONS

Multiparametric magnetic resonance imaging (mpMRI) including T2-weighted (T2w), diffusion-weighted and dynamic contrast-enhanced MRI according to the prostate imaging reporting and data system (PIRADS), MR-targeted biopsy, most frequently MR/TRUS image fusion biopsy.

FINDINGS AND PERFORMANCE

Prostate cancer is characterized by low signal intensity on T2w MRI, restricted water diffusion and pronounced and early uptake of contrast enhancement. Sensitivity and specificity according to the current literature are ca. 80% and 90%, respectively.

PRACTICAL RECOMMENDATIONS

In cases of suspected prostate cancer, most accurate are mpMRI according to PIRADS and in cases of positive findings, MRI-targeted biopsy, most frequently as MRI/TRUS image fusion biopsy.

Specimen Provenance Testing Identifies Contamination That Affects Molecular Prognostic Assay Results in Prostate Cancer Biopsy Specimens

OBJECTIVE

To determine if tissue contamination in histologic specimens can significantly affect the results of prognostic molecular markers that are routinely used as confirmatory tests to safely assign appropriate candidates to prostate cancer active surveillance protocols.

MATERIALS AND METHODS

This study evaluates 2134 cases from a single, large urology practice that were successfully tested for DNA specimen provenance verification using short tandem repeat analysis for the presence of a significant level of contaminating DNA. After removal of the contamination, 5 of the samples were retested, and the results of the molecular diagnostic test were compared.

RESULTS

Forty-nine of the 2134 cases (2.3%) sent for DNA provenance analysis were found to possess significant levels of contamination. Of these 49 cases, 7 were resent for a repeat molecular diagnostic test after being decontaminated. Five of these prostate cancer specimens had sufficient tissue and RNA to give a more accurate cell cycle progression (CCP) score. The average absolute change in these patients' CCP scores was 0.48, with a minimum of 0.1-unit and a maximum of 1.0-unit difference. These changes in CCP scores are significant enough to cause meaningful alterations in a patient's calculated 10-year mortality rate, as defined by their combined risk score.

CONCLUSION

DNA contamination in unstained tissue sections sent for prognostic prostate cancer molecular diagnostic testing occurs in 2.3% of the cases, and can be of a magnitude that affects the results and subsequent clinical decision of appropriateness for active surveillance.

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.

Assessment of Serum microRNA Biomarkers to Predict Reclassification of Prostate Cancer in Patients on Active Surveillance

PURPOSE

Conventional clinical variables cannot accurately differentiate indolent from aggressive prostate cancer in patients on active surveillance. We investigated promising circulating miRNA biomarkers to predict the reclassification of active surveillance cases.

MATERIALS AND METHODS

We collected serum samples from 2 independent active surveillance cohorts of 196 and 133 patients for the training and validation, respectively, of candidate miRNAs. All patients were treatment naïve and diagnosed with Gleason score 6 prostate cancer. Samples were collected prior to potential reclassification. We analyzed 9 circulating miRNAs previously shown to be associated with prostate cancer progression. Logistic regression and ROC analyses were performed to assess the predictive ability of miRNAs and clinical variables.

RESULTS

A 3-miR (miRNA-223, miRNA-24 and miRNA-375) score was significant to predict patient reclassification (training OR 2.72, 95% CI 1.50-4.94 and validation OR 3.70, 95% CI 1.29-10.6). It was independent of clinical characteristics in multivariable models. The ROC AUC was maximized when combining the 3-miR score and prostate specific antigen, indicating additive predictive value. The 3-miR score plus the prostate specific antigen panel cutoff achieved 89% to 90% negative predictive value and 66% to 81% specificity.

CONCLUSIONS

The 3-miR score combined with prostate specific antigen represents a noninvasive biomarker panel with high negative predictive value. It may be used to identify patients on active surveillance who have truly indolent prostate cancer.

Current Management Strategy for Active Surveillance in Prostate Cancer

PURPOSE OF REVIEW

Active surveillance has been increasingly utilized as a strategy for the management of favorable-risk, localized prostate cancer. In this review, we describe contemporary management strategies of active surveillance, with a focus on traditional stratification schemes, new prognostic tools, and patient outcomes.

RECENT FINDINGS

Patient selection, follow-up strategy, and indication for delayed intervention for active surveillance remain centered around PSA, digital rectal exam, and biopsy findings. Novel tools which include imaging, biomarkers, and genetic assays have been investigated as potential prognostic adjuncts; however, their role in active surveillance remains institutionally dependent. Although 30-50% of patients on active surveillance ultimately undergo delayed treatment, the vast majority will remain free of metastasis with a low risk of dying from prostate cancer. The optimal method for patient selection into active surveillance is unknown; however, cancer-specific mortality rates remain excellent. New prognostication tools are promising, and long-term prospective, randomized data regarding their use in active surveillance will be beneficial.

Prognostic utility of biopsy-derived cell cycle progression score in patients with National Comprehensive Cancer Network low-risk prostate cancer undergoing radical prostatectomy: implications for treatment guidance

OBJECTIVES

To determine the prognostic utility of the cell cycle progression (CCP) score in men with National Comprehensive Cancer Network (NCCN)-defined low-risk prostate cancer (PCa) undergoing radical prostatectomy (RP).

PATIENTS AND METHODS

Men who underwent RP for Gleason score ≤6 PCa at three institutions (Martini Clinic [MC], Durham Veterans Affairs Medical Center [DVA] and Intermountain Healthcare [IH]) were identified. The CCP score was obtained from diagnostic (DVA, IH) or simulated biopsies (MC). The primary outcome was biochemical recurrence (BCR; prostate-specific antigen ≥0.2 ng/mL) after RP. The prognostic utility of the CCP score was assessed using Kaplan-Meier analysis and multivariable Cox proportional hazards models in the subset of men meeting NCCN low-risk criteria and in the overall cohort.

RESULTS

Among the 236 men identified, 80% (188/236) met the NCCN low-risk criteria. Five-year BCR-free survival for the low (<0), intermediate (0-1) and high (>1) CCP score groups was 89.2%, 80.4%, 64.7%, respectively, in the low-risk cohort (P = 0.03), and 85.9%, 79.1%, 63.1%, respectively, in the overall cohort (P = 0.041). In multivariable models adjusting for clinical and pathological variables with the Cancer of the Prostate Risk Assessment (CAPRA) score, the CCP score was an independent predictor of BCR in the low-risk (hazard ratio [HR] 1.77 per unit score, 95% confidence interval [CI] 1.21, 2.58; P = 0.003) and overall cohorts (HR 1.41 per unit score, 95% CI 1.02, 1.96; P = 0.039).

CONCLUSION

In a cohort of men with NCCN-defined low-risk PCa, the CCP score improved clinical risk stratification of men who were at increased risk of BCR, which suggests the CCP score could improve the assessment of candidacy for active surveillance and guide optimum treatment selection in these patients with otherwise similar clinical characteristics.