Atypical Small Acinar Proliferation and High Grade Prostatic Intraepithelial Neoplasia: Should We Be Concerned? An Observational Cohort Study with a Minimum Follow-Up of 3 Years

A single centre service evaluation of the pre-biopsy mpMRI pathway for prostate cancer diagnosis

Aim:

To study the efficacy and impact of the local pre-biopsy multiparametric magnetic resonance imaging (mpMRI) pathway for prostate cancer diagnosis.

Methods:

In this tertiary centre, 570 patients had prostate mpMRI across a 6-month period in 2019. A total of 511 patients met inclusion criteria for retrospective analysis. MRI reporting used the Prostate Imaging-Reporting and Data System (PI-RADS) v2.1. These were assessed alongside histological outcomes and diagnostic times. PI-RADS ⩾ 3 were recommended for biopsy consideration. Gleason scoring ⩾ 3 + 4 and 3 + 3 were used to define clinically and non-clinically significant prostate cancer (csPCa and nsPCa), respectively.

Results:

Overall prostate cancer prevalence was 40% (204/511, csPCa in 31.1%) with an overall biopsy avoidance of 32.1% (164/511). Around 69.7% (356/511) scored PI-RADS ⩾ 3 and 30.3% (155/511) scored PI-RADS 1–2. About 22.6% (35/155) of PI-RADS 1–2 patients proceeded to biopsy, demonstrating a negative predictive value of 91.43% for csPCa. For PI-RADS ⩾ 3 patients, 63.4% (197/312) of those biopsied had cancer (Gleason ⩾ 3 + 3), with 50% (156/312) demonstrating csPCa. Around 76.7% (102/133) of PI-RADS 5, 35.3% (48/136) of PI-RADS 4, 14.0% (6/43) of PI-RADS 3 and 8.6% (3/35) of PI-RADS 1–2 scores demonstrated csPCa. Overall median prostate-specific antigen (PSA) density was 0.15 ng/mL2 (IQR: 0.10–0.27/mL2). PSA density were significantly different across PI-RADS cohorts ( H = 118.8, p < 0.0001) and across all three biopsy outcomes ( H = 99.72, p < 0.0001). Only 34.3% (119/347) of biopsied patients met the NHS 28-day standard. MRI acquisition and reporting met the 14-day local standard in 96.1% (491/511). The biopsy was the most delayed component with a median of 20 days (IQR: 8–43).

Conclusion:

Pre-biopsy mpMRI with PI-RADS scoring safely avoided biopsy in almost one-third (32.1%) of patients. The use of PSA-density in risk stratifying PI-RADS 3 lesions has informed local practice in the period 2020–2021, with implementation of a PSA-density threshold of 0.12 ng/mL2. Biopsy scheduling issues and anaesthetic requirements need to be overcome to improve diagnostic waiting times.

Level of evidence:

2

The current recommendation for the management of isolated high-grade prostatic intraepithelial neoplasia

OBJECTIVE

To analyse the current predictive value of isolated high-grade prostatic intraepithelial neoplasia (HGPIN) for clinically significant prostate cancer (csPCa) detection in repeat biopsies.

PATIENTS AND METHODS

A cohort of 293 men with isolated HGPIN detected in previous biopsies performed without multiparametric magnetic resonance imaging (mpMRI), and who underwent repeat biopsy within 1 to 3 years, was analysed. Pre-repeat biopsy mpMRI and guided biopsies to suspicious lesions (Prostate Imaging - Reporting and Data System [PI-RADS] ≥3) and/or and systematic biopsies were performed. Persistent prostate cancer (PCa) suspicion, defined as sustained serum prostate-specific antigen level >4 ng/mL and/or abnormal digital rectal examination, was present in 248 men (84.6%), and was absent in 45 men (15.4%). A control group of 190 men who had no previous HGPIN, atypical small acinar proliferation or HGPIN with atypia who were scheduled to undergo repeat biopsy due to persistent PCa suspicion were also analysed. csPCa was defined as tumours of Grade Group ≥2.

RESULTS

In the subset of 45 men with isolated HGPIN, in whom PCa suspicion disappeared, only one csPCa (2.2%) and one insignificant PCa (iPCa) were detected. csPCa was detected in 34.7% of men with persistent PCa suspicion and previous HGPIN, and in 28.4% of those without previous HGPIN (P =0.180). iPCa was detected in 12.1% and 6.3%, respectively (P =0.039). Logistic regression analysis showed that the risk of csPCa detection was not predicted by previous HGPIN: odds ratio (OR) 1.369 (95% confidence interval [CI] 0.894-2.095; P =0.149); however, previous HGPIN increased the risk of iPCa detection: OR 2.043 (95% CI 1.016-4.109; P =0.006).

CONCLUSION

The risk of csPCa in men with isolated HGPIN, in whom PCa suspicion disappears, is extremely low. Moreover, in those men in whom PCa suspicion persists, the risk of csPCa is not influenced by the previous finding of HGPIN. However, previous HGPIN increases the risk of iPCa detection. Therefore, repeat prostate biopsy should not be recommended solely because of a previous HGPIN.

Atypical small acinar proliferation and its significance in pathological reports in modern urological times

Atypical small acinar proliferation is a histopathological diagnosis of unspecified importance in prostate needle-biopsy reports, suggestive but not definitive for cancer. The terminology corresponds to some uncertainty in the biopsy report, as the finding might represent an underlying non-cancerous pathology mimicking cancer or an under-sampled prostate cancer site. Therefore, traditional practice favors an immediate repeat biopsy. However, in modern urological times, the need of urgent repeat biopsy is being challenged by some authors as in the majority of cases, the grade of cancer found in subsequent biopsy is reported to be low or the disease to be non-significant. On the other hand, high risk disease cannot be excluded, whereas no clinical or pathological factors can predict the final outcome. In this review, we discuss the significance of the diagnosis of atypical small acinar proliferation in the biopsy report, commenting on its importance in modern urological practice.

Natural history of widespread high grade prostatic intraepithelial neoplasia and atypical small acinar proliferation: should we rebiopsy them all?

OBJECTIVE

To evaluate the premalignant potential of high-grade prostatic intraepithelial neoplasia (HGPIN) and atypical small acinar proliferation (ASAP).

METHODS

Patients diagnosed with monofocal HGPIN (mHGPIN), widespread HGPIN (≥4 cores, wHGPIN) and/or ASAP who underwent at least one rebiopsy during their follow-up, were enrolled. All enrollment biopsies underwent central pathologic revision. Risks for PCa were estimated using Fine and Gray method for competing risk.

RESULTS

Pathologic revision changed the original diagnosis in 32.3% of cases. Among 336 cases enrolled, PCa was diagnosed in 164 (48.8%), and more specifically in 20 (30.3%) mHGPIN, 10 (34.5%) wHGPIN, 101 (54.0%) ASAP, and 33 (61.1%) HGPIN + ASAP (mean follow-up 124 months). Most PCa were Gleason score 6(3 + 3) (51.0%) and 7(3 + 4) (34.3%). On multivariate analysis, HGPIN + ASAP (HR 2.76, p < 0.001) and ASAP alone (HR 2.41, p < 0.001) were the only lesions significantly associated with PCa development. Of all cancers detected, 64.3% were at first rebiopsy. A rebiopsy performed within 3 months after ASAP diagnosis had a 45% chance of finding PCa. At Kaplan-Meier survival curves, median PCa-free survival was 48.1 months for HGPIN + ASAP and 64.9 months for ASAP (p 0.0005 at Log-rank test). At 1 year, 70% of HGPIN + ASAP, 73% of ASAP, 89% of wHGPIN, and 84% of mHGPIN were PCa-free.

CONCLUSION

The diagnosis of ASAP and HGPIN strongly relies on the expertise of dedicated uro-pathologists. Finding of ASAP is a strong risk factor for a subsequent PCa diagnosis, advising a rebiopsy, possibly within 3 months. m/wHGPIN should not be routinely rebiopsied.

Diagnostic Accuracy of a MR Protocol Acquired with and without Endorectal Coil for Detection of Prostate Cancer: A Multicenter Study

Introduction

The purpose of this study was to compare diagnostic accuracy of a prostate multiparametric magnetic resonance imaging (mpMRI) protocol for detection of prostate cancer between images acquired with and without en-dorectal coil (ERC).

Materials

This study was approved by the regional ethics committee. Between 2014 and 2015, 33 patients (median age 51.3 years; range 42.1-77.3 years) who underwent prostate-MRI at 3T scanners at 2 different institutions, acquired with (mpMRI_ERC) and without (mpMRI_PPA) ERC and who received radical prostatectomy, were included in this retrospective study. Two expert readers (R1, R2) attributed a PI-RADS version 2 score for the most suspect (i. e. index) lesion for mpMRI_PPA and mpMRI_ERC. Sensitivity and positive predictive value for detection of index lesions were assessed using 2 × 2 contingency tables. Differences between groups were tested using the McNemar test. Whole-mount histopathology served as reference standard.

Results

On a quadrant-basis cumulative sensitivity ranged between 0.61-0.67 and 0.76-0.88 for mpMRI_PPA and mpMRI_ERC protocols, respectively (p > 0.05). Cumulative positive predictive value ranged between 0.80-0.81 and 0.89-0.91 for mpMRI_PPA and mpMRI_ERC protocols, respectively. The differences were not statistically significant for R1 (p = 0.267) or R2 (p = 0.508).

Conclusion

Our results suggest that there may be no significant differences for detection of prostate cancer between images acquired with and without an ERC.