Comparing confirmatory biopsy outcomes between MRI-targeted biopsy and standard systematic biopsy among men being enrolled in prostate cancer active surveillance

Role of targeted biopsy, perilesional biopsy, random biopsy, and their combination in the detection of clinically significant prostate cancer by mpMRI/transrectal ultrasonography fusion biopsy in confirmatory biopsy during active surveillance program

BACKGROUND

Based on the findings of different trials in biopsy naïve patients, target biopsy (TB) plus random biopsy (RB) during mpMRI-guided transrectal ultrasound fusion biopsy (FB) are often also adopted for the biopsy performed during active surveillance (AS) programs. At the moment, a clear consensus on the extent and modalities of the procedure is lacking.

OBJECTIVE

To evaluate the increase in diagnostic accuracy achieved by perilesional biopsy (PL) and different RB schemes during FB performed in AS protocol.

DESIGN, SETTING, AND PARTICIPANTS

We collected prospectively the data of 112 consecutive patients with low- or very-low-risk prostate cancer; positive mpMRI underwent biopsy at a single academic institution in the context of an AS protocol.

INTERVENTION(S)

mpMRI/transrectal US FB with Hitachi RVS system with 3 TB and concurrent transrectal 24-core RB.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

The diagnostic yield of the different possible biopsy schemes (TB only; TB + 4 perilesional (PL) cores; TB + 12-core RB; TB + 24-core RB) was compared by the McNemar test. Univariable and multivariable regression analyses were adopted to identify predictors of any cancer, Gleason grade group (GGG) ≥2 cancers, and the presence of GGG≥2 cancers in the larger schemes only.

RESULTS AND LIMITATIONS

The detection rate of GGG ≥2 cancers increased to 30%, 39%, and 49% by adding 4 PL cores, 14, and 24 RB cores, respectively, to TB cores (all p values <0.01). On the whole, TB alone, 14-core RB, and 24-core-RB identified 38%, 47%, and 56% of all the GGG ≥2 cancers. Such figures increased to 62% by adding to TB 4 PL cores, and to 80% by adding 14 RB cores. Most of the differences were observed in PI-RADS 4 lesions.

CONCLUSIONS

We found that PL biopsy increased the detection rate of GGG ≥2 cancers as compared with TB alone. However, the combination of those cores missed a large percentage of the CS cancers identified with larger RB cores, including a 20% of CS cancers diagnosed only by the combination of TB plus 24-core RB.

A Multivariable Approach Using Magnetic Resonance Imaging to Avoid a Protocol-based Prostate Biopsy in Men on Active Surveillance for Prostate Cancer-Data from the International Multicenter Prospective PRIAS Study

BACKGROUND

There is ongoing discussion whether a multivariable approach including magnetic resonance imaging (MRI) can safely prevent unnecessary protocol-advised repeat biopsy during active surveillance (AS).

OBJECTIVE

To determine predictors for grade group (GG) reclassification in patients undergoing an MRI-informed prostate biopsy (MRI-Bx) during AS and to evaluate whether a confirmatory biopsy can be omitted in patients diagnosed with upfront MRI.

DESIGN, SETTING, AND PARTICIPANTS

The Prostate cancer Research International: Active Surveillance (PRIAS) study is a multicenter prospective study of patients on AS (www.prias-project.org). We selected all patients undergoing MRI-Bx (targeted ± systematic biopsy) during AS.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

A time-dependent Cox regression analysis was used to determine the predictors of GG progression/reclassification in patients undergoing MRI-Bx. A sensitivity analysis and a multivariable logistic regression analysis were also performed.

RESULTS AND LIMITATIONS

A total of 1185 patients underwent 1488 MRI-Bx sessions. The time-dependent Cox regression analysis showed that age (per 10 yr, hazard ratio [HR] 0.84 [95% confidence interval {CI} 0.71-0.99]), MRI outcome (Prostate Imaging Reporting and Data System [PIRADS] 3 vs negative HR 2.46 [95% CI 1.56-3.88], PIRADS 4 vs negative HR 3.39 [95% CI 2.28-5.05], and PIRADS 5 vs negative HR 4.95 [95% CI 3.25-7.56]), prostate-specific antigen (PSA) density (per 0.1 ng/ml cm³, HR 1.20 [95% CI 1.12-1.30]), and percentage positive cores on the last systematic biopsy (per 10%, HR 1.16 [95% CI 1.10-1.23]) were significant predictors of GG reclassification. Of the patients with negative MRI and a PSA density of <0.15 ng/ml cm³ (n = 315), 3% were reclassified to GG ≥2 and 0.6% to GG ≥3. At the confirmatory biopsy, reclassification to GG ≥2 and ≥3 was observed in 23% and 7% of the patients diagnosed without upfront MRI and in 19% and 6% of the patients diagnosed with upfront MRI, respectively. The multivariable analysis showed no significant difference in upgrading at the confirmatory biopsy between patients diagnosed with or without upfront MRI.

CONCLUSIONS

Age, MRI outcome, PSA density, and percentage positive cores are significant predictors of reclassification at an MRI-informed biopsy. Patients with negative MRI and a PSA density of <0.15 ng/ml cm³ can safely omit a protocol-based prostate biopsy, whereas in other patients, a multivariable approach is advised. Being diagnosed with upfront MRI appears not to significantly affect reclassification risk; hence, a confirmatory MRI-Bx cannot totally be omitted yet.

PATIENT SUMMARY

A protocol-based prostate biopsy while on active surveillance can be omitted in patients with negative magnetic resonance imaging (MRI) and prostate-specific antigen density <0.15 ng/ml cm³. A confirmatory biopsy cannot simply be omitted in all patients diagnosed with upfront MRI.

Micro-ultrasound Versus Magnetic Resonance Imaging in Prostate Cancer Active Surveillance

Accurate assessment of tumor grade is critical for active surveillance (AS) in prostate cancer. We compared magnetic resonance imaging (MRI) and micro-ultrasound scoring (Prostate Imaging-Reporting and Data System [PI-RADS] v2.1 vs Prostate Risk Identification using Micro-ultrasound [PRI-MUS]) in 128 men on AS. The primary outcome was upgrading to Gleason grade group (GG) ≥2. There was no difference in GG ≥2 detection between the imaging techniques (PRI-MUS score ≥3: 33/34, 98%; PI-RADS score ≥3: 29/34, 85%; p = 0.22). The sensitivity, specificity, and positive and negative predictive values for GG ≥2 detection were 97%, 32%, 34%, and 97% with PRI-MUS ≥3, and 85%, 53%, 40%, and 91% with PI-RADS ≥3, respectively. Upgrading to GG ≥2 was more likely for PRI-MUS ≥3 than for PRI-MUS ≤2 scores (odds ratio 15.5, 95% confidence interval 2.0-118.5). A limitation is the lack of blinding to the MRI results. In conclusion, detection of upgrading to GG ≥2 during AS appears similar when using micro-ultrasound or MRI to inform prostate biopsy.

Patient summary

We looked at a novel imaging technology, micro-ultrasound, in patients undergoing biopsy during active surveillance for prostate cancer. We found that micro-ultrasound can detect prostate cancer that may require treatment at a similar rate to that with magnetic resonance imaging (MRI) scans.

Confirmatory transperineal saturation prostate biopsy combined with mpMRI decrease the reclassification rate in men enrolled in Active Surveillance: Our experience in 100 men submitted to eight-years scheduled biopsy

Introduction: The reclassification rate for clinically significant prostate cancer (csPCa) in men enrolled in Active Surveillance (AS) as been prospective-ly evaluated. Patients and methods: One hundred patients with very low risk PCa underwent after 8 years a scheduled transperineal prostate biopsy (SPBx = 20 cores) combined with additionalmpMRI/TRUS fusion biopsies (4 cores) of lesions PI-RADS scores ≥ 3. All the patients, after initial diagnosis, previously had mpMRI evaluation combined with transperineal saturation prostate biopsy (confirmatory and 3-year scheduled biopsy). Risk reclassification at repeat biopsy triggering the recommen-dation for active treatment was defined as over 3 or more than 10% of positive cores, Gleason score > 6/ISUP Grade Group ≥ 2, greatest percentage of cancer (GPC) > 50%.Results: Multiparametric MRI was suspicious (PI-RADS ≥ 3) in 30 of 100 cases (30.0%); 70 (70.0%) vs. 20 (20.0%) vs. 10(10.0%) patients had a PI-RADS score ≤ 2 vs. 3 vs. 4, respec-tively. Two (2.0%) patients with PI-RADS score 3 and 4 were upgraded (ISUP Grade Group 2); SPBx and MRI/TRUS fusion biopsy diagnosed 100% and 0% of csPCa, respectively. Conclusions: Transperineal SPBx combined with mpMRI at ini-tial confirmatory biopsy allow to select an high number of men at very low risk of reclassification during the AS follow up (2.0%of the cases at 8 years from diagnosis); these data could be use-ful to reduce the number of scheduled repeated prostate biopsy during the AS follow up.

Machine Learning-Based Prediction of Pathological Upgrade From Combined Transperineal Systematic and MRI-Targeted Prostate Biopsy to Final Pathology: A Multicenter Retrospective Study

Objective

This study aimed to evaluate the pathological concordance from combined systematic and MRI-targeted prostate biopsy to final pathology and to verify the effectiveness of a machine learning-based model with targeted biopsy (TB) features in predicting pathological upgrade.

Materials and Methods

All patients in this study underwent prostate multiparametric MRI (mpMRI), transperineal systematic plus transperineal targeted prostate biopsy under local anesthesia, and robot-assisted laparoscopic radical prostatectomy (RARP) for prostate cancer (PCa) sequentially from October 2016 to February 2020 in two referral centers. For cores with cancer, grade group (GG) and Gleason score were determined by using the 2014 International Society of Urological Pathology (ISUP) guidelines. Four supervised machine learning methods were employed, including two base classifiers and two ensemble learning-based classifiers. In all classifiers, the training set was 395 of 565 (70%) patients, and the test set was the remaining 170 patients. The prediction performance of each model was evaluated by area under the receiver operating characteristic curve (AUC). The Gini index was used to evaluate the importance of all features and to figure out the most contributed features. A nomogram was established to visually predict the risk of upgrading. Predicted probability was a prevalence rate calculated by a proposed nomogram.

Results

A total of 515 patients were included in our cohort. The combined biopsy had a better concordance of postoperative histopathology than a systematic biopsy (SB) only (48.15% vs. 40.19%, p = 0.012). The combined biopsy could significantly reduce the upgrading rate of postoperative pathology, in comparison to SB only (23.30% vs. 39.61%, p < 0.0001) or TB only (23.30% vs. 40.19%, p < 0.0001). The most common pathological upgrade occurred in ISUP GG1 and GG2, accounting for 53.28% and 20.42%, respectively. All machine learning methods had satisfactory predictive efficacy. The overall accuracy was 0.703, 0.768, 0.794, and 0.761 for logistic regression, random forest, eXtreme Gradient Boosting, and support vector machine, respectively. TB-related features were among the most contributed features of a prediction model for upgrade prediction.

Conclusion

The combined effect of SB plus TB led to a better pathological concordance rate and less upgrading from biopsy to RP. Machine learning models with features of TB to predict PCa GG upgrading have a satisfactory predictive efficacy.

Two Decades of Active Surveillance for Prostate Cancer in a Single-Center Cohort: Favorable Outcomes after Transurethral Resection of the Prostate

OBJECTIVE

To report the outcomes of active surveillance (AS) for low-risk prostate cancer (PCa) in a single-center cohort.

PATIENTS AND METHODS

This is a prospective, single-center, observational study. The cohort included all patients who underwent AS for PCa between December 1999 and December 2020 at our institution. Follow-up appointments (FU) ended in February 2021.

RESULTS

A total of 413 men were enrolled in the study, and 391 had at least one FU. Of those who followed up, 267 had PCa diagnosed by transrectal ultrasound (TRUS)-guided biopsy (T1c: 68.3%), while 124 were diagnosed after transurethral resection of the prostate (TURP) (T1a/b: 31.7%). Median FU was 46 months (IQR 25-90). Cancer specific survival was 99.7% and overall survival was 92.3%. Median reclassification time was 11.2 years. After 20 years, 25% of patients were reclassified within 4.58 years, 6.6% opted to switch to watchful waiting, 4.1% died, 17.4% were lost to FU, and 46.8% remained on AS. Those diagnosed by TRUS had a significantly higher reclassification rate than those diagnosed by TURP (p < 0.0001). Men diagnosed by targeted MRI/TRUS fusion biopsy tended to have a higher reclassification probability than those diagnosed by conventional template biopsies (p = 0.083).

CONCLUSIONS

Our single-center cohort spanning over two decades revealed that AS remains a safe option for low-risk PCa even in the long term. Approximately half of AS enrollees will eventually require definitive treatment due to disease progression. Men with incidental prostate cancer were significantly less likely to have disease progression.

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.

Impact of Early Confirmatory Tests on Upgrading and Conversion to Treatment in Prostate Cancer Patients on Active Surveillance

OBJECTIVES

To assess the impact of confirmatory tests on active surveillance (AS) biopsy disease reclassification and progression to treatment in men with favorable risk prostate cancer (FRPC).

METHODS

We searched the MUSIC registry for men with FRPC managed with AS without or with a confirmatory test. Confirmatory tests included (1) repeat prostate biopsy, (2) genomic tests, (3) prostate magnetic resonance imaging (MRI), or (4) MRI followed by a post-MRI biopsy. Confirmatory test results were deemed reassuring (RA) or nonreassuring (nonRA) according to predefined criteria. Kaplan-Meier curves and multivariable Cox regression models were used to compare surveillance biopsy disease reclassification-free survival and treatment-free survival.

RESULTS

Of the 2,514 men with FRPC who were managed on AS, 1211 (48%) men obtained a confirmatory test. We noted differences in the 12-month unadjusted surveillance biopsy disease reclassification-free probability (68%, 83%, and 90%, P < .0001) and 24-month unadjusted treatment-free probability (55%, 81%, and 79%, P < .0001), for men with nonRA confirmatory tests, no confirmatory test, and RA confirmatory tests, respectively. Excluding patients with genomic confirmatory tests, men with RA confirmatory tests were associated with a lower hazard (hazard ratio [HR] 0.57, 95% confidence interval [CI] 0.38-0.84, P = .005) and men with nonRA confirmatory tests had an increased hazard (HR 1.97, 95% CI 1.22-3.19, P = .006) of surveillance disease reclassification compared with men without confirmatory tests in the multivariable model.

CONCLUSION

These data suggest men with RA confirmatory tests have less surveillance biopsy reclassification and remain on AS longer than men with nonRA test results. Confirmatory tests may help risk stratify men considering active surveillance.