Prostate cancer upgrading with serial prostate magnetic resonance imaging and repeat biopsy in men on active surveillance: are confirmatory biopsies still necessary?

Is MRI ready to replace biopsy during active surveillance?

Active surveillance (AS) is a conservative management option recommended for patients diagnosed with low-risk prostate cancer (PCa) and selected cases with intermediate-risk PCa. The adoption of prostate MRI in the primary diagnostic setting has sparked interest in its application during AS. This review aims to examine the role and performance of multiparametric MRI (mpMRI) across the entire AS pathway, from initial stratification to follow-up, also relative to the utilization of the Prostate Cancer Radiological Estimation of Change in Sequential Evaluation (PRECISE) criteria. Given the high negative predictive value of mpMRI in detecting clinically significant PCa (csPCa), robust evidence supports its use in patient selection and risk stratification at the time of diagnosis or confirmatory biopsy. However, conflicting results have been observed when using MRI in evaluating disease progression during follow-up. Key areas requiring clarification include addressing the clinical significance of MRI-negative csPCa, optimizing MRI quality, determining the role of biparametric MRI (bpMRI) or mpMRI protocols, and integrating artificial intelligence (AI) for improved performance. CLINICAL RELEVANCE STATEMENT: MRI plays an essential role in the selection, stratification, and follow up of patients in active surveillance (AS) for prostate cancer. However, owing to existing limitations, it cannot fully replace biopsies in the context of AS. KEY POINTS: Multiparametric MRI (mpMRI) has become a crucial tool in active surveillance (AS) for prostate cancer (PCa). Conflicting results have been observed regarding multiparametric MRI efficacy in assessing disease progression. Standardizing MRI-guided protocols will be critical in addressing current limitations in active surveillance for prostate cancer.

PRECISE Version 2: Updated Recommendations for Reporting Prostate Magnetic Resonance Imaging in Patients on Active Surveillance for Prostate Cancer

BACKGROUND AND OBJECTIVE

The Prostate Cancer Radiological Estimation of Change in Sequential Evaluation (PRECISE) recommendations standardise the reporting of prostate magnetic resonance imaging (MRI) in patients on active surveillance (AS) for prostate cancer. An international consensus group recently updated these recommendations and identified the areas of uncertainty.

METHODS

A panel of 38 experts used the formal RAND/UCLA Appropriateness Method consensus methodology. Panellists scored 193 statements using a 1-9 agreement scale, where 9 means full agreement. A summary of agreement, uncertainty, or disagreement (derived from the group median score) and consensus (determined using the Interpercentile Range Adjusted for Symmetry method) was calculated for each statement and presented for discussion before individual rescoring.

KEY FINDINGS AND LIMITATIONS

Participants agreed that MRI scans must meet a minimum image quality standard (median 9) or be given a score of 'X' for insufficient quality. The current scan should be compared with both baseline and previous scans (median 9), with the PRECISE score being the maximum from any lesion (median 8). PRECISE 3 (stable MRI) was subdivided into 3-V (visible) and 3-NonV (nonvisible) disease (median 9). Prostate Imaging Reporting and Data System/Likert ≥3 lesions should be measured on T2-weighted imaging, using other sequences to aid in the identification (median 8), and whenever possible, reported pictorially (diagrams, screenshots, or contours; median 9). There was no consensus on how to measure tumour size. More research is needed to determine a significant size increase (median 9). PRECISE 5 was clarified as progression to stage ≥T3a (median 9).

CONCLUSIONS AND CLINICAL IMPLICATIONS

The updated PRECISE recommendations reflect expert consensus opinion on minimal standards and reporting criteria for prostate MRI in AS.

PATIENT SUMMARY

The Prostate Cancer Radiological Estimation of Change in Sequential Evaluation (PRECISE) recommendations are used in clinical practice and research to guide the interpretation and reporting of magnetic resonance imaging for patients on active surveillance for prostate cancer. An international panel has updated these recommendations, clarified the areas of uncertainty, and highlighted the areas for further research.

Cancer Detection Rate and Abnormal Interpretation Rate of Prostate MRI in Patients With Low-Grade Cancer

PURPOSE

The aim of this study was to evaluate the utility of cancer detection rate (CDR) and abnormal interpretation rate (AIR) in prostate MRI for patients with low-grade prostate cancer (PCa).

METHODS

This three-center retrospective study included patients who underwent prostate MRI from 2017 to 2021 with known low-grade PCa (Gleason score 6) without prior treatment. Patient-level highest Prostate Imaging Reporting & Data System (PI-RADS®) score and pathologic diagnosis within 1 year after MRI were used to evaluate the diagnostic performance of prostate MRI in detecting clinically significant PCa (csPCa; Gleason score ≥ 7). The metrics AIR, CDR, and CDR adjusted for pathologic confirmation rate were calculated. Radiologist-level AIR-CDR plots were shown. Simulation AIR-CDR lines were created to assess the effects of different diagnostic performances of prostate MRI and the prevalence of csPCa.

RESULTS

A total of 3,207 examinations were interpreted by 33 radiologists. Overall AIR, CDR, and CDR adjusted for pathologic confirmation rate at PI-RADS 3 to 5 (PI-RADS 4 and 5) were 51.7% (36.5%), 22.1% (18.8%), and 30.7% (24.6%), respectively. Radiologist-level AIR and CDR at PI-RADS 3 to 5 (PI-RADS 4 and 5) were in the 36.8% to 75.6% (21.9%-57.5%) range and the 16.3%-28.7% (10.9%-26.5%) range, respectively. In the simulation, changing parameters of diagnostic performance or csPCa prevalence shifted the AIR-CDR line.

CONCLUSIONS

The authors propose CDR and AIR as performance metrics in prostate MRI and report reference performance values in patients with known low-grade PCa. There was variability in radiologist-level AIR and CDR. Combined use of AIR and CDR could provide meaningful feedback for radiologists to improve their performance by showing relative performance to other radiologists.

Active Surveillance for Prostate Cancer: Expanding the Role of MR Imaging and the Use of PRECISE Criteria

Multiparametric magnetic resonance (MR) imaging has had an expanding role in active surveillance (AS) for prostate cancer. It can improve the accuracy of prostate biopsies, assist in patient selection, and help monitor cancer progression. The PRECISE recommendations standardize reporting of serial MR imaging scans during AS. We summarize the evidence on MR imaging-led AS and provide a clinical primer to help report using the PRECISE criteria. Some limitations to both serial imaging and the PRECISE recommendations must be considered as we move toward a more individualized risk-stratified approach to AS.

The PRECISE Recommendations for Prostate MRI in Patients on Active Surveillance for Prostate Cancer: A Critical Review

The Prostate Cancer Radiological Estimation of Change in Sequential Evaluation (PRECISE) recommendations were published in 2016 to standardize the reporting of MRI examinations performed to assess for disease progression in patients on active surveillance for prostate cancer. Although a limited number of studies have reported outcomes from use of PRECISE in clinical practice, the available studies have demonstrated PRECISE to have high pooled NPV but low pooled PPV for predicting progression. Our experience in using PRECISE in clinical practice at two teaching hospitals has highlighted issues with its application and areas requiring clarification. This Clinical Perspective critically appraises PRECISE on the basis of this experience, focusing on the system's key advantages and disadvantages and exploring potential changes to improve the system's utility. These changes include consideration of image quality when applying PRECISE scoring, incorporation of quantitative thresholds for disease progression, adoption of a PRECISE 3F sub-category for progression not qualifying as substantial, and comparisons with both the baseline and most recent prior examinations. Items requiring clarification include derivation of a patient-level score in patients with multiple lesions, intended application of PRECISE score 5 (i.e., if requiring development of disease that is no longer organ-confined), and categorization of new lesions in patients with prior MRI-invisible disease.

Prostate Cancer Radiological Estimation of Change in Sequential Evaluation (PRECISE) Magnetic Resonance Imaging Scoring to Predict Clinical Outcomes in Active Surveillance for Grade Group 1 Prostate Cancer

OBJECTIVE

To determine whether radiological change on serial multiparametric magnetic resonance imaging scored using the Prostate Cancer Radiological Estimation of Change in Sequential Evaluation (PRECISE) Scoring system predicts grade reclassification (GR) at surveillance biopsy in men on active surveillance (AS) with Grade Group 1 (GG1) prostate cancer (PCa).

METHODS

We retrospectively reviewed records of 255 men with low-risk PCa on AS with magnetic resonance imaging (MRI)-informed diagnostic and confirmatory biopsies and studied the subset who had surveillance biopsies (n = 163) within 6months of an interval MRI.

RESULTS

We studied 309 PRECISE scores in 255 men. 14% demonstrated radiological progression (PRECISE 4-5) on interval MRI performed within 24months, compared to 34% of those whose interval MRI was performed at a >3-year interval (P = .002). 28% (46/163) of men undergoing surveillance biopsy experienced GR to ≥ GG2 PCa. There was no significant increase in the rate of GR with increasing PRECISE score (PRECISE 1-2: 24%, PRECISE 3: 23%, PRECISE 4-5: 38%; P = .11). There was a significant increase in the rate of GR with increasing PI-RADS score (P < .05). On multivariable analysis, a PI-RADS score of 4-5 was significantly associated with GR compared to men who had a highest PI-RADS ≤3 (OR=1.98 [95% CI: 1.45-3.09, P = .01]).

CONCLUSION

In a low-risk AS cohort with limited follow-up, a patient's highest PI-RADS rather than their PRECISE score on interval MRI was predictive of GR on surveillance biopsy.

Delta radiomic patterns on serial bi-parametric MRI are associated with pathologic upgrading in prostate cancer patients on active surveillance: preliminary findings

Objective

The aim of this study was to quantify radiomic changes in prostate cancer (PCa) progression on serial MRI among patients on active surveillance (AS) and evaluate their association with pathologic progression on biopsy.

Methods

This retrospective study comprised N = 121 biopsy-proven PCa patients on AS at a single institution, of whom N = 50 at baseline conformed to the inclusion criteria. ISUP Gleason Grade Groups (GGG) were obtained from 12-core TRUS-guided systematic biopsies at baseline and follow-up. A biopsy upgrade (AS+) was defined as an increase in GGG (or in number of positive cores) and no upgrade (AS-) was defined when GGG remained the same during a median period of 18 months. Of N = 50 patients at baseline, N = 30 had MRI scans available at follow-up (median interval = 18 months) and were included for delta radiomic analysis. A total of 252 radiomic features were extracted from the PCa region of interest identified by board-certified radiologists on 3T bi-parametric MRI [T2-weighted (T2W) and apparent diffusion coefficient (ADC)]. Delta radiomic features were computed as the difference of radiomic feature between baseline and follow-up scans. The association of AS+ with age, prostate-specific antigen (PSA), Prostate Imaging Reporting and Data System (PIRADS v2.1) score, and tumor size was evaluated at baseline and follow-up. Various prediction models were built using random forest (RF) classifier within a threefold cross-validation framework leveraging baseline radiomics (Cbr), baseline radiomics + baseline clinical (Cbrbcl), delta radiomics (CΔr), delta radiomics + baseline clinical (CΔrbcl), and delta radiomics + delta clinical (CΔrΔcl).

Results

An AUC of 0.64 ± 0.09 was obtained for Cbr, which increased to 0.70 ± 0.18 with the integration of clinical variables (Cbrbcl). CΔr yielded an AUC of 0.74 ± 0.15. Integrating delta radiomics with baseline clinical variables yielded an AUC of 0.77 ± 0.23. CΔrΔclresulted in the best AUC of 0.84 ± 0.20 (p < 0.05) among all combinations.

Conclusion

Our preliminary findings suggest that delta radiomics were more strongly associated with upgrade events compared to PIRADS and other clinical variables. Delta radiomics on serial MRI in combination with changes in clinical variables (PSA and tumor volume) between baseline and follow-up showed the strongest association with biopsy upgrade in PCa patients on AS. Further independent multi-site validation of these preliminary findings is warranted.

Association of quantifiable prostate MRI parameters with any and large cribriform pattern in prostate cancer patients undergoing radical prostatectomy

PURPOSE

Cribriform pattern has recently been recognized as an important independent risk factor for prostate cancer (PCa) outcome. This study aimed to identify the association of quantifiable prostate magnetic resonance imaging (MRI) parameters with any and large cribriform pattern at radical prostatectomy (RP) specimens.

METHODS

Preoperative prostate MRI's from 188 men undergoing RP between 2010 and 2018 were retrospectively acquired. RP specimens of the patients were revised for Gleason score (GS), and presence of any and large cribriform pattern. MRI parameters such as MRI visibility, PI-RADS score, lowest apparent diffusion coefficient (ADC) value, lesion size, and radiologic extra-prostatic extension (EPE) were reviewed. The association of prostate MRI parameters for presence of any and large cribriform pattern at RP was analysed using logistic regression.

RESULTS

116/188 (61.7%) PCa patients had any cribriform and 36/188 (19.1%) large cribriform pattern at RP. 171/188 (91.0%) men had MRI-visible lesions; 111/116 (95.7%) tumours with any and 36/36 (100%) with large cribriform pattern were visible at MRI. PCa with any and large cribriform pattern both had lower ADC values than those without (p < 0.001). In adjusted analysis, lowest ADC value was as an independent predictor for any cribriform (Odds Ratio (OR) 0.2, 95% Confidence Interval (CI) 0.1-0.8; p = 0.01) and large cribriform pattern (OR 0.2, 95% CI 0.1-0.7; p = 0.01), while other parameters were not.

CONCLUSIONS

The majority of PCa with cribriform pattern at RP were visible at MRI, and lowest ADC value was an independent predictor for both any and large cribriform pattern.

Prostate imaging-reporting and data system version 2 has improved biopsy tumor grade accuracy: a single, tertiary institutional experience

PURPOSE

To investigate change in prostate biopsy accuracy regarding tumor grade before and after the release of Prostate Imaging-Reporting and Data System version 2 (PI-RADSv2) in a single tertiary institution.

METHODS

We retrospectively evaluated 1191 patients with biopsy-proven prostate cancer (PCa) who had undergone prostate magnetic resonance imaging (MRI) and surgery before (2013 cohort, n = 394) and 5 years after PI-RADSv2 release (2020 cohort, n = 797). The highest tumor grade of each biopsy and surgical specimen was recorded, respectively. We compared concordant, underestimated, and overestimated biopsy rates regarding tumor grade to surgery between two cohorts, respectively. For patients who underwent both prostate MRI and biopsy at our institution, we investigated proportion of pre-biopsy MRI, age, and prostate-specific antigen of patients, and performed logistic regression to analyze which parameters are associated with concordant biopsy.

RESULTS

Concordant and underestimated biopsy rates were significantly different between two cohorts: Concordance and underestimation rates were 47.2% and 46.3% in 2013 and 54.5% and 36.4% in 2020 (p = .019; p = .003), respectively. Overestimated biopsy rates were similar (p = .993). Proportion of pre-biopsy MRI was significantly higher in 2020 than in 2013 (80.9% versus 4.9%; p < .001), and was independently associated with concordant biopsy results in multivariate analysis (odds ratio = 1.486; 95% confidence interval, 1.057-2.089; p = .022).

CONCLUSIONS

There was a significant change in proportion of pre-biopsy MRI before and after the release of PI-RADSv2 in patients who underwent surgery for PCa. This change appears to have improved biopsy accuracy regarding tumor grade by reducing underestimation.

mpMRI Interpretation in Active Surveillance for Prostate Cancer-An overview of the PRECISE score

Active surveillance (AS) is now included in all major guidelines for patients with low-risk PCa and selected patients with intermediate-risk PCa. Several studies have highlighted the potential benefit of multiparametric magnetic resonance imaging (mpMRI) in AS and it has been adopted in some guidelines. However, uncertainty remains about whether serial mpMRI can help to safely reduce the number of required repeat biopsies under AS. In 2017, the European School of Oncology initiated the Prostate Cancer Radiological Estimation of Change in Sequential Evaluation (PRECISE) panel which proposed the PRECISE scoring system to assess the likelihood of radiological tumor progression on serial mpMRI. The PRECISE scoring system remains the only major system evaluated in multiple publications. In this review article, we discuss the current body of literature investigating the application of PRECISE as it is not as yet an established standard in mpMRI reporting. We delineate the strengths of PRECISE and its potential added value. Also, we underline potential weaknesses of the PRECISE scoring system, which might be tackled in future versions to further increase its value in AS.

Combination of fusion guided multiparametric MRI-transrectal US with systematic biopsy of the prostate for the detection of clinically significant prostate cancer: A prospective single-center study

PURPOSE

To investigate the diagnostic efficacy of fusion guided multiparametric MRI (mpMRI)-transrectal ultrasound (TRUS) biopsy versus systematic biopsy of the prostate in patients with suspicion of prostate cancer.

METHODS

A total of 185 patients with PI-RADS 3 lesions or higher underwent fusion guided targeted and systematic prostate biopsy. Histology of samples was correlated with PI-RADS score and biopsy method for each patient.

RESULTS

A total of 81/185 (43.8%) cases positive for cancer were detected; 23/81 (28.4%) cases with clinically insignificant prostate cancer-insPCa and 58/81 (71.6%) cases with clinically significant prostate cancer-csPCa. There was a statistically significant difference in the overall detection of adenocarcinomas between methods (p = .035, McNemar test). Moreover, there was a statistically significant difference in the detection of insPCa between the two methods (p = .004, McNemar test). Systematic biopsy detected 13 patients with insPCa more (14.4%) than the targeted biopsy method. However, there is no statistical difference in the detection rate of csPCa between the two methods (p = 1, McNemar test). When both techniques were combined more cases of csPCa were detected.

CONCLUSION

The combined implementation of fusion-guided targeted mpMRI-TRUS and systematic biopsy of the prostate provides higher detection number of csPCa, compared to each method alone. The potential of fusion-guided mpMRI-TRUS biopsy of the prostate needs to be further assessed since each method has its limitations; therefore, systematic prostate biopsy still plays an important role in clinical practice.

Abbreviated Versus Multiparametric Prostate MRI in Active Surveillance for Prostate-Cancer Patients: Comparison of Accuracy and Clinical Utility as a Decisional Tool

(1) Purpose: To compare the diagnostic accuracy between full multiparametric contrast-enhanced prostate MRI (mpMRI) and abbreviated dual-sequence prostate MRI (dsMRI) in men with clinically significant prostate cancer (csPCa) who were candidates for active surveillance. (2) Materials and Methods: Fifty-four patients with a diagnosis of low-risk PCa in the previous 6 months had a mpMRI scan prior to a saturation biopsy and a subsequent MRI cognitive transperineal targeted biopsy (for PI-RADS ≥ 3 lesions). The dsMRI images were obtained from the mpMRI protocol. The images were selected by a study coordinator and assigned to two readers blinded to the biopsy results (R1 and R2). Inter-reader agreement for clinically significant cancer was evaluated with Cohen's kappa. The dsMRI and mpMRI accuracy was calculated for each reader (R1 and R2). The clinical utility of the dsMRI and mpMRI was investigated with a decision-analysis model. (3) Results: The dsMRI sensitivity and specificity were 83.3%, 31.0%, 75.0%, and 23.8%, respectively, for R1 and R2. The mpMRI sensitivity and specificity were 91.7%, 31.0%, 83.3%, and 23.8%, respectively, for R1 and R2. The inter-reader agreement for the detection of csPCa was moderate (k = 0.53) and good (k = 0.63) for dsMRI and mpMRI, respectively. The AUC values for the dsMRI were 0.77 and 0.62 for the R1 and R2, respectively. The AUC values for the mpMRI were 0.79 and 0.66 for R1 and R2, respectively. No AUC differences were found between the two MRI protocols. At any risk threshold, the mpMRI showed a higher net benefit than the dsMRI for both R1 and R2. (4) Conclusions: The dsMRI and mpMRI showed similar diagnostic accuracy for csPCa in male candidates for active surveillance.

The current role of MRI for guiding active surveillance in prostate cancer

Active surveillance (AS) is the recommended treatment option for low-risk and favourable intermediate-risk prostate cancer management, preserving oncological and functional outcomes. However, active monitoring using relevant parameters in addition to the usual clinical, biological and pathological considerations is necessary to compensate for initial undergrading of the tumour or to detect early progression without missing the opportunity to provide curative therapy. Indeed, several studies have raised concerns about inadequate biopsy sampling at diagnosis. However, the implementation of baseline MRI and targeted biopsy have led to improved initial stratification of low-risk disease; baseline MRI correlates well with disease characteristics and AS outcomes. The use of follow-up MRI during the surveillance phase also raises the question of the requirement for serial biopsies in the absence of radiological progression and the possibility of using completely MRI-based surveillance, with triggers for biopsies based solely on MRI findings. This concept of a tailored-risk, imaging-based monitoring strategy is aimed at reducing invasive procedures. However, the abandonment of serial biopsies in the absence of MRI progression can probably not yet be recommended in routine practice, as the data from real-life cohorts are heterogeneous and inconclusive. Thus, the evolution towards a routine, fully MRI-guided AS pathway has to be preceded by ensuring quality programme assessment for MRI reading and by demonstrating its safety in prospective trials.

Systematic Review of Active Surveillance for Clinically Localised Prostate Cancer to Develop Recommendations Regarding Inclusion of Intermediate-risk Disease, Biopsy Characteristics at Inclusion and Monitoring, and Surveillance Repeat Biopsy Strategy

CONTEXT

There is uncertainty regarding the most appropriate criteria for recruitment, monitoring, and reclassification in active surveillance (AS) protocols for localised prostate cancer (PCa).

OBJECTIVE

To perform a qualitative systematic review (SR) to issue recommendations regarding inclusion of intermediate-risk disease, biopsy characteristics at inclusion and monitoring, and repeat biopsy strategy.

EVIDENCE ACQUISITION

A protocol-driven, Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA)-adhering SR incorporating AS protocols published from January 1990 to October 2020 was performed. The main outcomes were criteria for inclusion of intermediate-risk disease, monitoring, reclassification, and repeat biopsy strategies (per protocol and/or triggered). Clinical effectiveness data were not assessed.

EVIDENCE SYNTHESIS

Of the 17 011 articles identified, 333 studies incorporating 375 AS protocols, recruiting 264 852 patients, were included. Only a minority of protocols included the use of magnetic resonance imaging (MRI) for recruitment (n = 17), follow-up (n = 47), and reclassification (n = 26). More than 50% of protocols included patients with intermediate or high-risk disease, whilst 44.1% of protocols excluded low-risk patients with more than three positive cores, and 39% of protocols excluded patients with core involvement (CI) >50% per core. Of the protocols, ≥80% mandated a confirmatory transrectal ultrasound biopsy; 72% (n = 189) of protocols mandated per-protocol repeat biopsies, with 20% performing this annually and 25% every 2 yr. Only 27 protocols (10.3%) mandated triggered biopsies, with 74% of these protocols defining progression or changes on MRI as triggers for repeat biopsy.

CONCLUSIONS

For AS protocols in which the use of MRI is not mandatory or absent, we recommend the following: (1) AS can be considered in patients with low-volume International Society of Urological Pathology (ISUP) grade 2 (three or fewer positive cores and cancer involvement ≤50% CI per core) or another single element of intermediate-risk disease, and patients with ISUP 3 should be excluded; (2) per-protocol confirmatory prostate biopsies should be performed within 2 yr, and per-protocol surveillance repeat biopsies should be performed at least once every 3 yr for the first 10 yr; and (3) for patients with low-volume, low-risk disease at recruitment, if repeat systematic biopsies reveal more than three positive cores or maximum CI >50% per core, they should be monitored closely for evidence of adverse features (eg, upgrading); patients with ISUP 2 disease with increased core positivity and/or CI to similar thresholds should be reclassified.

PATIENT SUMMARY

We examined the literature to issue new recommendations on active surveillance (AS) for managing localised prostate cancer. The recommendations include setting criteria for including men with more aggressive disease (intermediate-risk disease), setting thresholds for close monitoring of men with low-risk but more extensive disease, and determining when to perform repeat biopsies (within 2 yr and 3 yearly thereafter).

The utility of prostate MRI within active surveillance: description of the evidence

Purpose

We present an overview of the literature regarding the use of MRI in active surveillance of prostate cancer.

Methods

Both MEDLINE^® and Cochrane Library were queried up to May 2020 for studies of men on active surveillance with MRI and later confirmatory biopsy. The terms studied were ‘prostate cancer’ as the anchor followed by two of the following: active surveillance, surveillance, active monitoring, MRI, NMR, magnetic resonance imaging,  MRI, and multiparametric MRI. Studies were excluded if pathologic reclassification (GG1 →  ≥ GG2) and PI-RADS or equivalent was not reported.

Results

Within active surveillance, baseline MRI is effective for identifying clinically significant prostate cancer and thus associated with fewer reclassification events. A positive initial MRI (≥ PI-RADS 3) with GG1 identified at biopsy has a positive predictive value (PPV) of 35–40% for reclassification by 3 years. MRI possessed a stronger negative predictive value, with a negative MRI (≤ PI-RADS 2) yielding a negative predictive value of up to 85% at 3 years. Surveillance MRI, obtained after initial biopsy, yielded a PPV of 11–65% and NPV of 85–95% for reclassification.

Conclusion

MRI is useful for initial risk stratification of prostate cancer in men on active surveillance, especially if MRI is negative when imaging is obtained during surveillance. While useful, MRI cannot replace biopsy and further research is necessary to fully integrate MRI into active surveillance.

Repeat MRI during active surveillance: natural history of prostatic lesions and upgrading rates

OBJECTIVES

To assess upgrading rates in patients on active surveillance (AS) for prostate cancer (PCa) after serial multiparametric magnetic resonance imaging (mpMRI).

METHODS

We conducted a retrospective analysis of 558 patients. Five different criteria for mpMRI progression were used: 1) a Prostate Imaging Reporting and Data System (PI-RADS) score increase; 2) a lesion size increase; 3) an extraprostatic extension score increase; 4) overall mpMRI progression; and 5) the number of criteria met for mpMRI progression (0 vs 1 vs 2-3). In addition, two definitions of PCa upgrading were evaluated: 1) International Society of Urological Pathology Grade Group (ISUP GG) ≥2 with >10% of pattern 4 and 2) ISUP GG ≥ 3. Estimated annual percent changes methodology was used to show the temporal trends of mpMRI progression criteria. The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of mpMRI progression criteria were also analysed. Multivariable logistic regression models tested PCa upgrading rates.

RESULTS

Lower rates over time for all mpMRI progression criteria were observed. The NPV of serial mpMRI scans ranged from 90.5% to 93.5% (ISUP GG≥2 with >10% of pattern 4 PCa upgrading) and from 98% to 99% (ISUP GG≥3 PCa upgrading), depending on the criteria used for mpMRI progression. A prostate-specific antigen density (PSAD) threshold of 0.15 ng/mL/mL was used to substratify those patients who would be able to skip a prostate biopsy. In multivariable logistic regression models assessing PCa upgrading rates, all five mpMRI progression criteria achieved independent predictor status.

CONCLUSION

During AS, approximately 27% of patients experience mpMRI progression at first repeat MRI. However, the rates of mpMRI progression decrease over time at subsequent mpMRI scans. Patients with stable mpMRI findings and with PSAD < 0.15 ng/mL/mL could safely skip surveillance biopsies. Conversely, patients who experience mpMRI progression should undergo a prostate biopsy.

Use of multiparametric magnetic resonance imaging (mpMRI) in active surveillance for low-risk prostate cancer: a scoping review on the benefits and harm of mpMRI in different biopsy scenarios

BACKGROUND

There is uncertainty on how multiparametric MRI (mpMRI) and MRI-targeted biopsy (MRI-TB) can be best used to manage low-risk prostate cancer patients on Active Surveillance (AS). We performed a scoping review to evaluate the benefits and harm associated with four different biopsy scenarios in which mpMRI can be implemented in AS.

METHODS

Medline, Embase and Cochrane Library databases (1 January 2013-18 September 2020) were searched. Included studies were on men with low-risk prostate cancer enrolled in AS, who had mpMRI ± MRI-TB and standard prostate biopsy (systematic transrectal ultrasound or transperineal saturation biopsy), at confirmatory or follow-up biopsy. Primary outcomes were the number of Gleason score upgrades and biopsies avoided.

RESULTS

Eight confirmatory biopsy studies and three follow-up biopsy studies were included. Compared to the benchmark of using standard biopsy (SB) for all men, the addition of MRI-TB increased the detection of Gleason score upgrades at both confirmatory (6/8 studies) and follow-up biopsy (3/3 studies), with increments of 1.7-11.8 upgrades per 100 men. 6/7 studies suggested that the use of a positive mpMRI to triage men for MRI-TB or SB alone would detect fewer Gleason score upgrades than benchmark at confirmatory biopsy, but the combination of MRI-TB and SB would detect more upgrades than the benchmark. For follow-up biopsy, the evidence on mpMRI triage biopsy scenarios was inconclusive due to the small number of included studies.

CONCLUSIONS

The addition of MRI-TB to benchmark (SB for all men) maximises the detection of Gleason score upgrades at confirmatory and follow-up biopsy. When the use of mpMRI to triage men for a biopsy is desired, the combination of MRI-TB and SB should be considered for men with positive mpMRI at confirmatory biopsy. The evidence on mpMRI triage scenarios was inconclusive in the follow-up biopsy setting.

Guy's and St Thomas NHS Foundation active surveillance prostate cancer cohort: a characterisation of a prostate cancer active surveillance database

Background

The routine clinical use of serum prostatic specific antigen (PSA) testing has allowed earlier detection of low-grade prostate cancer (PCa) with more favourable characteristics, leading to increased acceptance of management by active surveillance (AS). AS aims to avoid over treatment in men with low and intermediate-risk PCa and multiple governing bodies have described several AS protocols. This study provides a descriptive profile of the Guy’s and St Thomas NHS Foundation Trust (GSTT) AS cohort as a platform for future research in AS pathways in PCa.

Methods

Demographic and baseline characteristics were retrospectively collected in a database for patients at the GSTT AS clinic with prospective collection of follow-up data from 2012. Seven hundred eighty-eight men being monitored at GSTT with histologically confirmed intermediate-risk PCa, at least 1 follow-up appointment and diagnostic characteristics consistent with AS criteria were included in the profile. Descriptive statistics, Kaplan-Meier survival curves and multivariable Cox proportion hazards regression models were used to characterize the cohort.

Discussion

A relatively large proportion of the cohort includes men of African/Afro-Caribbean descent (22%). More frequent use of magnetic resonance imaging and trans-perineal biopsies at diagnosis was observed among patients diagnosed after 2012. Those who underwent trans-rectal ultrasound diagnostic biopsy received their first surveillance biopsy 20 months earlier than those who underwent trans-perineal diagnostic biopsy. At 3 years, 76.1% men remained treatment free. Predictors of treatment progression included Gleason score 3 + 4 (Hazard ratio (HR): 2.41, 95% Confidence interval (CI): 1.79–3.26) and more than 2 positive cores taken at biopsy (HR: 2.65, CI: 1.94–3.62). A decreased risk of progressing to treatment was seen among men diagnosed after 2012 (HR: 0.72, CI: 0.53–0.98).

Conclusion

An organised biopsy surveillance approach, via two different AS pathways according to the patient’s diagnostic method, can be seen within the GSTT cohort. Risk of patients progressing to treatment has decreased in the period since 2012 compared with the prior period with more than half of the cohort remaining treatment free at 5 years, highlighting that the fundamental aims of AS at GSTT are being met. Thus, this cohort is a good resource to investigate the AS treatment pathway.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-021-08255-z.

Reliability of Serial Prostate Magnetic Resonance Imaging to Detect Prostate Cancer Progression During Active Surveillance: A Systematic Review and Meta-analysis

CONTEXT

Although magnetic resonance imaging (MRI) is broadly implemented into active surveillance (AS) protocols, data on the reliability of serial MRI in order to help guide follow-up biopsy are inconclusive.

OBJECTIVE

To assess the diagnostic estimates of serial prostate MRI for prostate cancer (PCa) progression during AS.

EVIDENCE ACQUISITION

We systematically searched PubMed, Scopus, and Web of Science databases to select studies analyzing the association between changes on serial prostate MRI and PCa progression during AS. We included studies that provided data for MRI progression, which allowed us to calculate diagnostic estimates. We compared Prostate Cancer Radiological Estimation of Change in Sequential Evaluation (PRECISE) accuracy with institution-specific definitions.

EVIDENCE SYNTHESIS

We included 15 studies with 2240 patients. Six used PRECISE criteria and nine institution-specific definitions of MRI progression. The pooled PCa progression rate, which included histological progression to Gleason grade ≥2, was 27%. The pooled sensitivity and specificity were 0.59 (95% confidence interval [CI] 0.44-0.73) and 0.75 (95% CI 0.66-0.84) respectively. There was significant heterogeneity between included studies. Depending on PCa progression prevalence, the pooled negative predictive value for serial prostate MRI ranged from 0.81 (95% CI 0.73-0.88) to 0.88 (95% CI 0.83-0.93) and the pooled positive predictive value ranged from 0.37 (95% CI 0.24-0.54) to 0.50 (95% CI 0.36-0.66). There were no significant differences in the pooled sensitivity (p = 0.37) and specificity (p = 0.74) of PRECISE and institution-specific schemes.

CONCLUSIONS

Serial MRI still should not be considered a sole factor for excluding PCa progression during AS, and changes on MRI are not accurate enough to indicate PCa progression. There was a nonsignificant trend toward improved diagnostic estimates of PRECISE recommendations. These findings highlight the need to further define the optimal triggers and timing of biopsy during AS, as well as the need for optimizing the quality, interpretation, and reporting of serial prostate MRI.

PATIENT SUMMARY

Our study suggests that serial prostate magnetic resonance imaging (MRI) alone in patients on active surveillance is not accurate enough to reliably rule out or rule in prostate cancer progression. Other clinical factors and biomarkers along with serial MRI are required to safely tailor the intensity of follow-up biopsies.

Changes in Magnetic Resonance Imaging Using the Prostate Cancer Radiologic Estimation of Change in Sequential Evaluation Criteria to Detect Prostate Cancer Progression for Men on Active Surveillance

BACKGROUND

The ability of serial magnetic resonance imaging (MRI) to capture pathologic progression during active surveillance (AS) remains in question.

OBJECTIVE

To determine whether changes in MRI are associated with pathologic progression for patients on AS.

DESIGN, SETTING, AND PARTICIPANTS

From July 2007 through January 2020, we identified all patients evaluated for AS at our institution. Following confirmatory biopsy, a total of 391 patients who underwent surveillance MRI and biopsy at least once were identified (median follow-up of 35.6 mo, interquartile range 19.7-60.6).

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

All MRI intervals were scored using the "Prostate Cancer Radiologic Estimation of Change in Sequential Evaluation" (PRECISE) criteria, with PRECISE scores =4 considered a positive change in MRI. A generalized estimating equation-based logistic regression analysis was conducted for all intervals with a PRECISE score of <4 to determine the predictors of Gleason grade group (GG) progression despite stable MRI.

RESULTS AND LIMITATIONS

A total of 621 MRI intervals were scored by PRECISE and validated by biopsy. The negative predictive value of stable MRI (PRECISE score <4) was greatest for detecting GG1 to?=?GG3 disease (0.94 [0.91-0.97]). If 2-yr surveillance biopsy were performed exclusively for a positive change in MRI, 3.7% (4/109) of avoided biopsies would have resulted in missed progression from GG1 to?=?GG3 disease. Prostate-specific antigen (PSA) density (odds ratio 1.95 [1.17-3.25], p?=? 0.01) was a risk factor for progression from GG1 to =GG3 disease despite stable MRI.

CONCLUSIONS

In patients with GG1 disease and stable MRI (PRECISE score <4) on surveillance, grade progression to?=?GG3 disease is not common. In patients with grade progression detected on biopsy despite stable MRI, elevated PSA density appeared to be a risk factor for progression to?=?GG3 disease.

PATIENT SUMMARY

For patients with low-risk prostate cancer on active surveillance, the risk of progressing to grade group 3 disease is low with a stable magnetic resonance image (MRI) after 2?yr. Having higher prostate-specific antigen density increases the risk of progression, despite having a stable MRI.

Diagnostic Accuracy and Prognostic Value of Serial Prostate Multiparametric Magnetic Resonance Imaging in Men on Active Surveillance for Prostate Cancer

BACKGROUND

Multiparametric magnetic resonance imaging (MRI) is increasingly utilized to improve the detection of clinically significant prostate cancer. Evidence for serial MRI in men on active surveillance (AS) is lacking.

OBJECTIVE

To evaluate the role of MRI in detecting Gleason grade group (GG) ≥2 disease in confirmatory and subsequent surveillance biopsies for men on AS.

DESIGN, SETTING, AND PARTICIPANTS

This was a single-center study of men with low-risk prostate cancer enrolled in an AS cohort between 2006 and 2018. All men were diagnosed by systematic biopsy and underwent MRI prior to confirmatory ("MRI1") and subsequent surveillance ("MRI2") biopsies. MRI lesions were scored with Prostate Imaging Reporting and Data System (PI-RADS) version 2.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

The primary outcome was biopsy upgrade to GG ≥ 2 prostate cancer, and the secondary outcome was definitive treatment. Test characteristics for PI-RADS score were calculated. Multivariable logistic and Cox proportional hazard regression models were used to determine the associations between PI-RADS score change and outcomes, on a per-examination basis.

RESULTS AND LIMITATIONS

Of 125 men with a median follow-up of 78 mo, 38% experienced an increase in PI-RADS scores. The sensitivity and positive predictive value of PI-RADS ≥3 for GG ≥ 2 disease improved from MRI1 to MRI2 (from 85% to 91% and from 26% to 49%, respectively). An increase in PI-RADS scores from MRI1 to MRI2 was associated with GG ≥ 2 (odds ratio [OR] 4.8, 95% confidence interval [CI] 1.7-13.2) compared with PI-RADS 1-3 on both MRI scans. Men with PI-RADS 4-5 lesions on both MRI scans had a higher likelihood of GG ≥ 2 than patients with PI-RADS 1-3 lesions on both (OR 3.3, 95% CI 1.3-8.6). Importantly, any increase in PI-RADS scores was independently associated with definitive treatment (hazard ratio 3.9, 95% CI 1.3-11.9). This study was limited by its retrospective, single-center design.

CONCLUSIONS

The prognostic value of MRI improves with serial examination and provides additional risk stratification. Validation in other cohorts is needed.

PATIENT SUMMARY

We looked at the role of serial prostate magnetic resonance imaging in men with low-risk prostate cancer on active surveillance at the University of California, San Francisco. We found that both consistently visible and increasingly suspicious lesions were associated with biopsy upgrade and definitive treatment.

Should we perform systematic biopsies in case of suspicious MRI for prostate cancer in 2020? A review of literature

CONTEXT

Multiparametric magnetic resonance imaging (MRI) is now recommended before performing prostate biopsies, looking for suspicious lesions to perform targeted biopsies (TB). However, the association or exclusive performance of systematic biopsies (SB), criticized for its morbidity and for the detection of insignificant cancers, remains debated.

OBJECTIVE

To perform a literature review to answer three questions: (1) In the presence of a suspicious MRI lesion, should we always perform SB in addition to TB? (2) Can we avoid SB when considering focal treatment? (3) Is there an increase in adverse events when associating SB with TB?

SOURCES

A non-systematic literature review was carried out on Medline in April 2020 using the keywords "MRI", "PROSTATE CANCER", "SYSTEMATIC BIOPSY", "TARGETED BIOPSY", "ADVERSE EVENTS". The references of the selected articles were analyzed for additional articles. Selection of Studies published in the last five years were analyzed and retained if the available data made it possible to answer one of the three questions asked.

RESULTS

In biopsy-naive patients, the added value of SB to TB for detection of significative cancer varied from +5 to+7% and was reduced to +1 to +3% in the case of a previous series of negative biopsies. For patients under active surveillance, this added value was higher, ranging from +8% to +17%. MRI has a negative predictive value of 85 to 95%, but this value drops to 55% for the detection of secondary or tertiary foci. The use of SB is necessary if focal treatment is considered. Serious complications from biopsies requiring hospitalization range from 1.4 to 6.9% and are increased by the number of previous biopsy series performed more than by the number of biopsies per series.

CONCLUSION

In the presence of a suspicious MRI lesion, SB is indicated in addition to TB but can be discussed in patients with previous negative biopsies. They are necessary if focal treatment is considered to aid surgical planning. Severe complications from biopsies do not seem to increase when SB are associated to TB, but rather with the number of biopsy series performed.

What to expect from a non-suspicious prostate MRI? A review

BACKGROUND

Many guidelines now recommend multiparametric MRI (mpMRI) prior to an initial or repeat prostate biopsy. However, clinical decision making for men with a non-suspicious mpMRI (Likert or PIRADS score 1-2) varies.

OBJECTIVES

To review the most recent literature to answer three questions. (1) Should we consider systematic biopsy if mpMRI is not suspicious? (2) Are there additional predictive factors that can help decide which patient should have a biopsy? (3) Can the low visibility of some cancers be explained and what are the implications?

SOURCES

A narrative review was performed in Medline databases using two searches with the terms "MRI" and "prostate cancer" and ("diagnosis" or "biopsy") and ("non-suspicious" or "negative" or "invisible"); "prostate cancer MRI visible". References of the selected articles were screened for additional articles.

STUDY SELECTION

Studies published in the last 5 years in English language were assessed for eligibility and selected if data was available to answer one of the three study questions.

RESULTS

Considering clinically significant cancer as ISUP grade≥2, the negative predictive value (NPV) of mpMRI in various settings and populations ranges from 76% to 99%, depending on cancer prevalence and the type of confirmatory reference test used. NPV is higher among patients with prior negative biopsy (88-96%), and lower for active surveillance patients (85-90%). The PSA density (PSAd) with a threshold of PSAd<0.15ng/ml/ml was the most studied and relevant predictive factor used in combination with mpMRI to rule out clinically significant cancer. Finally, mpMRI-invisible tumours appear to differ from a histopathological and genetic point of view, conferring clinical advantage to invisibility.

LIMITATIONS

Most published data come from expert centres and results may not be reproducible in all settings.

CONCLUSION

mpMRI has high diagnostic accuracy and in cases of negative mpMRI, PSA density can be used to determine which patient should have a biopsy. Growing knowledge of the mechanisms and genetics underlying MRI visibility will help develop more accurate risk calculators and biomarkers.

The role of multiparametric magnetic resonance imaging and magnetic resonance-guided biopsy in active surveillance for low-risk prostate cancer: A systematic review

The performance of multiparametric magnetic resonance imaging (mpMRI) and subsequent biopsy in monitoring prostate cancer in men on active surveillance (AS) have not been defined clearly. In this systematic review, we aimed to review current literature about the usage of MRI examination in men with low-risk prostate cancer during active surveillance. For that, we searched seven databases to include all studies reporting magnetic resonance imaging in the AS of low-risk prostate cancer. We finally included 11 studies with 1237 patients included. Our results showed an adequate sensitivity and specificity of both modalities to detect disease progression; including disease upgrading and upstaging. However, the performance in the prediction of unfavorable disease was inferior to the detection of upgrading and upstaging. In terms of MRGB, the previous literature agreed on the superiority of using a combination of different biopsy schemes to get a better progression section. Noteworthy, mp-MRI and MRGB had a good predictive value limited to the first year, with TRUSGB showing a superior role in detecting patients with a GS ≥ 7, after that. In conclusion, both of mpMRI and MRGB have shown an adequate performance on assessing disease progression in the AS of low-risk prostate cancer patients. They can be used for disease staging and grading for successful treatment planning.

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In comparison to the literature, few papers discuss the benefit of MRI screening in low-risk prostate cancer groups.

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Biopsy is considered more invasive than MRI, thus reducing the burden of such methods on the patients.

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PSA values can be misinterpreted especially that it can rise in other diseases such as Benign Prostatic Hyperplasia.