Overdiagnosis and stage migration of ISUP 2 disease due to mpMRI-targeted biopsy: facts or fictions

Navigating the evolving diagnostic and therapeutic landscape of low- and intermediate-risk prostate cancer

ABSTRACT

In this nonsystematic review of the literature, we explored the changing landscape of detection and treatment of low- and intermediate-risk prostate cancer (PCa). Through emphasizing improved cancer assessment with histology classification and genomics, we investigated key developments in PCa detection and risk stratification. The pivotal role of prostate magnetic resonance imaging (MRI) in the novel diagnostic pathway is examined, alongside the benefits and drawbacks of MRI-targeted biopsies for detection and tumor characterization. We also delved into treatment options, particularly active surveillance for intermediate-risk PCa. Outcomes are compared between intermediate- and low-risk patients, offering insights into tailored management. Surgical techniques, including Retzius-sparing surgery, precision prostatectomy, and partial prostatectomy for anterior cancer, are appraised. Each technique has the potential to enhance outcomes and minimize complications. Advancements in technology and radiobiology, including computed tomography (CT)/MRI imaging and positron emission tomography (PET) fusion, allow for precise dose adjustment and daily target monitoring with imaging-guided radiotherapy, opening new ways of tailoring patients' treatments. Finally, experimental therapeutic approaches such as focal therapy open new treatment frontiers, although they create new needs in tumor identification and tracking during and after the procedure.

Does Overgrading on Targeted Biopsy of Magnetic Resonance Imaging-visible Lesions in Prostate Cancer Lead to Overtreatment?

BACKGROUND AND OBJECTIVE

Targeted biopsy of the index prostate cancer (PCa) lesion on multiparametric magnetic resonance imaging (MRI) is effective in reducing the risk of overdiagnosis of indolent PCa. However, it remains to be determined whether MRI-targeted biopsy can lead to a stage shift via overgrading of the index lesion by focusing only on the highest-grade component, and to a subsequent risk of overtreatment. Our aim was to assess whether overgrading on MRI-targeted biopsy may lead to overtreatment, using radical prostatectomy (RP) specimens as the reference standard.

METHODS

Patients with clinically localized PCa who had positive MRI findings (Prostate Imaging-Reporting and Data System [PI-RADS] score ≥3) and Gleason grade group (GG) ≥2 disease detected on MRI-targeted biopsy were retrospectively identified from a prospectively maintained database that records all RP procedures from eight referral centers. Biopsy grade was defined as the highest grade detected. Downgrading was defined as lower GG for the RP specimen than for MRI-targeted biopsy. Overtreatment was defined as downgrading to RP GG 1 for cases with GG ≥2 on biopsy, or to RP low-burden GG 2 for cases with GG ≥3 on biopsy.

KEY FINDINGS AND LIMITATIONS

We included 1020 consecutive biopsy-naïve patients with GG ≥2 PCa on MRI-targeted biopsy in the study. Pathological analysis of RP specimens showed downgrading in 178 patients (17%). The transperineal biopsy route was significantly associated with a lower risk of downgrading (odds ratio 0.364, 95% confidence interval 0.142-0.814; p = 0.022). Among 555 patients with GG 2 on targeted biopsy, only 18 (3.2%) were downgraded to GG 1 on RP. Among 465 patients with GG ≥3 on targeted biopsy, three (0.6%) were downgraded to GG 1 and seven were downgraded to low-burden GG 2 on RP. The overall risk of overtreatment due to targeted biopsy was 2.7% (28/1020).

CONCLUSIONS AND CLINICAL IMPLICATIONS

Our multicenter study revealed no strong evidence that targeted biopsy results could lead to a high risk of overtreatment.

Transperineal versus Transrectal MRI/TRUS fusion-guided prostate biopsy in a large, ethnically diverse, and multiracial cohort

PURPOSE

To compare transperineal (TP) vs transrectal (TR) magnetic resonance imaging (MRI) and transrectal ultrasound (TRUS) fusion-guided prostate biopsy (PBx) in a large, ethnically diverse and multiracial cohort.

MATERIALS AND METHODS

Consecutive patients who underwent multiparametric (mp) MRI followed by TP or TR TRUS-fusion guided PBx, were identified from a prospective database (IRB #HS-13-00663). All patients underwent mpMRI followed by 12-14 core systematic PBx. A minimum of two additional target-biopsy cores were taken per PIRADS≥3 lesion. The endpoint was the detection of clinically significant prostate cancer (CSPCa; Grade Group, GG≥2). Statistical significance was defined as p<0.05.

RESULTS

A total of 1491 patients met inclusion criteria, with 480 undergoing TP and 1011 TR PBx. Overall, 11% of patients were Asians, 5% African Americans, 14% Hispanic, 14% Others, and 56% White, similar between TP and TR (p=0.4). For PIRADS 3-5, the TP PBx CSPCa detection was significantly higher (61% vs 54%, p=0.03) than TR PBx, but not for PIRADS 1-2 (13% vs 13%, p=1.0). After adjusting for confounders on multivariable analysis, Black race, but not the PBx approach (TP vs TR), was an independent predictor of CSPCa detection. The median maximum cancer core length (11 vs 8mm; p<0.001) and percent (80% vs 60%; p<0.001) were greater for TP PBx even after adjusting for confounders.

CONCLUSIONS

In a large and diverse cohort, Black race, but not the biopsy approach, was an independent predictor for CSPCa detection. TP and TR PBx yielded similar CSPCa detection rates; however the TP PBx was histologically more informative.

The impact of mpMRI-targeted vs systematic biopsy on the risk of prostate cancer downgrading at final pathology

PURPOSE

Although targeted biopsies (TBx) are associated with improved disease assessment, concerns have been raised regarding the risk of prostate cancer (PCa) overgrading due to more accurate biopsy core deployment in the index lesion.

METHODS

We identified 1672 patients treated with radical prostatectomy (RP) with a positive mpMRI and ISUP ≥ 2 PCa detected via systematic biopsy (SBx) plus TBx. We compared downgrading rates at RP (ISUP 4-5, 3, and 2 at biopsy, to a lower ISUP) for PCa detected via SBx only (group 1), via TBx only (group 2), and eventually for PCa detected with the same ISUP 2-5 at both SBx and TBx (group 3), using multivariable logistic regression models (MVA).

RESULTS

Overall, 12 vs 14 vs 6% (n = 176 vs 227 vs 96) downgrading rates were recorded in group 1 vs group 2 vs group 3, respectively (p < 0.001). At MVA, group 2 was more likely to be downgraded (OR 1.26, p = 0.04), as compared to group 1. Conversely, group 3 was less likely to be downgraded at RP (OR 0.42, p < 0.001).

CONCLUSIONS

Downgrading rates are highest when PCa is present in TBx only and, especially when the highest grade PCa is diagnosed by TBx cores only. Conversely, downgrading rates are lowest when PCa is identified with the same ISUP through both SBx and TBx. The presence of clinically significant disease at SBx + TBx may indicate a more reliable assessment of the disease at the time of biopsy potentially reducing the risk of downgrading at final pathology.

Residents and Consultants Have Equal Outcomes When Performing Transrectal Fusion Biopsies: A Randomized Clinical Trial

The aim of our study was to compare the performance of residents vs. consultants in transrectal fusion prostate biopsies (FUS-PBs), as well as patient-reported comfort. Between January 2021 and October 2022, a consecutive series of patients undergoing FUS-PBs were randomized into two groups: (A) FUS-PBs performed by a consultant; (B) FUS-PBs performed by trained residents (>50 procedures). All patients underwent FUS-PBs with 12 systematic cores and 3/6 target cores. The detection rate and number of positive cores in the target lesion were compared between groups, and the patient's discomfort after the procedure was evaluated using the VAS scale. Overall, 140 patients with a median age of 72 years were enrolled. Overall, 69/140 (49.3%) presented prostate cancer and 53/69 (76.8%) presented a clinically significant cancer (Grade Group ≥ 2). Consultants presented a detection rate of 37/70 (52.9%) and residents a detection rate of 32/70 (45.7%) (p > 0.2); the mean number of positive cores in the index lesion was similar in both groups (1.5 vs. 1.1; p > 0.10). In terms of the patients' experiences, the procedure was well tolerated, with a median VAS score of 2 in both groups, with no statistically significant differences. Residents showed satisfactory outcomes in terms of detection rate, procedural time, and patient comfort when performing prostate biopsies. Residents, after adequate training, can safely perform prostate biopsies.

MRI-Targeted Prostate Biopsy Introduces Grade Inflation and Overtreatment

Purpose

The use of MRI-targeted biopsies has led to lower detection of Gleason Grade Group 1 (GG1) prostate cancer and increased detection of GG2 disease. Although this finding is generally attributed to improved sensitivity and specificity of MRI for aggressive cancers, it might also be explained by grade inflation. Our objective was to determine the likelihood of definitive treatment and risk of post-treatment recurrence for patients with GG2 cancer diagnosed using targeted biopsies relative to men with GG1 cancer diagnosed using systematic biopsies.

Methods

We performed a retrospective study on a large tertiary centre registry (HUS Acamedic Datalake) to retrieve data on prostate cancer diagnosis, treatment, and cancer recurrence. We included patients with either GG1 with systematic biopsies (3317 men) or GG2 with targeted biopsies (554 men) from 1993 to 2019. We assessed the risk of curative treatment and recurrence after treatment. Kaplan-Meier survival curves were computed to assess treatment- and recurrence-free survival. Cox proportional hazards regression analysis was performed to assess the risk of posttreatment recurrence.

Results

Patients with systematic biopsy detected GG1 cancer had a significantly longer median time-to-treatment (31 months) than those with targeted biopsy detected GG2 cancer (4 months, p<0.0001). The risk of recurrence after curative treatment was similar between groups with the upper bound of 95% CI, excluding an important difference (HR: 0.94, 95% CI [0.71-1.25], p=0.7).

Conclusion

GG2 cancers detected by MRI-targeted biopsy are treated more aggressively than GG1 cancers detected by systematic biopsy, despite having similar oncologic risk. To prevent further overtreatment related to the MRI pathway, treatment guidelines from the pre-MRI era need to be updated to consider changes in the diagnostic pathway.

Incidence and Predicting Factors of Histopathological Features at Robot-Assisted Radical Prostatectomy in the mpMRI Era: Results of a Single Tertiary Referral Center

Background and Objectives: To describe the predictors of cribriform variant status and perineural invasion (PNI) in robot-assisted radical prostatectomy (RARP) histology. To define the rates of upgrading between biopsy specimens and final histology and their possible predictive factors in prostate cancer (PCa) patients undergoing RARP. Material and Methods: Within our institutional database, 265 PCa patients who underwent prostate biopsies and consecutive RARP at our center were enrolled (2018-2022). In the overall population, two independent multivariable logistic regression models (LRMs) predicting the presence of PNI or cribriform variant status at RARP were performed. In low- and intermediate-risk PCa patients according to D'Amico risk classification, three independent multivariable LRMs were fitted to predict upgrading. Results: Of all, 30.9% were low-risk, 18.9% were intermediate-risk and 50.2% were high-risk PCa patients. In the overall population, the rates of the cribriform variant and PNI at RARP were 55.8% and 71.1%, respectively. After multivariable LRMs predicting PNI, total tumor length in biopsy cores (>24 mm [OR: 2.37, p-value = 0.03], relative to <24 mm) was an independent predictor. After multivariable LRMs predicting cribriform variant status, PIRADS (3 [OR:15.37], 4 [OR: 13.57] or 5 [OR: 16.51] relative to PIRADS 2, all p = 0.01) and total tumor length in biopsy cores (>24 mm [OR: 2.47, p = 0.01], relative to <24 mm) were independent predicting factors. In low- and intermediate-risk PCa patients, the rate of upgrading was 74.4% and 78.0%, respectively. After multivariable LRMs predicting upgrading, PIRADS (PIRADS 3 [OR: 7.01], 4 [OR: 16.98] or 5 [OR: 20.96] relative to PIRADS 2, all p = 0.01) was an independent predicting factor. Conclusions: RARP represents a tailored and risk-adapted treatment strategy for PCa patients. The indication of RP progressively migrates to high-risk PCa after a pre-operative assessment. Specifically, the PIRADS score at mpMRI should guide the decision-making process of urologists for PCa patients.