MRI-targeted biopsy cores from prostate index lesions: assessment and prediction of the number needed

Enhancing Prostate Cancer Detection Accuracy in Magnetic Resonance Imaging-targeted Prostate Biopsy: Optimizing the Number of Cores Taken

Background and objective

The shift toward targeted biopsy (TBx) aims at enhancing prostate cancer (PCa) detection while reducing overdiagnosis of clinically insignificant disease. Despite the improved ability of TBx in identifying clinically significant PCa (csPCa), the optimal number and location of targeted cores remain unclear. This review aims to assess the optimal number of prostate biopsy magnetic resonance imaging (MRI)-targeted cores to detect csPCa.

Methods

A narrative literature search was conducted using PubMed, focusing on studies published between January 2014 and January 2024, addressing factors influencing targeted core numbers during prostate biopsy. The search included both retrospective and prospective studies, prioritizing those with substantial sample sizes and employing terms such as "prostate biopsy", "mpMRI", "core number", and "cancer detection".

Key findings and limitations

Two biopsy cores identified csPCa in 55-65% of cases. This detection rate improved to approximately 90% when the number of cores was ≥5. The inclusion of perilesional and systematic biopsies could maximize the detection of csPCa (from 10% to 45%), especially in patients under active surveillance or with prior negative biopsy results, although there is an increase in the overdiagnosis of indolent tumors (from 4% to 20%). Transperineal software-assisted target prostate biopsy may enhance cancer detection, particularly for tumors located at the apex/anterior part of the prostate. Increasing the number of TBx cores may incrementally raise the risk of complications (by 2-14% with each added core) and result in severe pain and significant discomfort for up to 17% and 25% of TBx patients, respectively. However, the overall rate and severity of these complications remain within acceptable limits.

Conclusions and clinical implications

The optimal number of cores for targeted prostate biopsies should balance minimizing sampling errors with effective cancer detection and should be tailored to each patient's unique prostate characteristics. Up to five cores per MRI target may be considered to enhance the detection of csPCa, with adjustments based on factors such as prostate and lesion volume, Prostate Imaging Reporting and Data System, biopsy techniques, complications, patient discomfort, and anxiety.

Patient summary

In this report, we found that increasing the number of biopsy cores up to ≥5 improves the detection rates of significant prostate cancer significantly to around 90%. Although inclusion of nearby and systematic biopsies enhances detection, increasing the biopsy count may lead to higher risks of complications and indolent tumors. A customized biopsy approach based on multiple variables could be helpful in determining the appropriate number of targeted biopsies on a case-by-case basis.

Added value of randomised biopsy to multiparametric magnetic resonance imaging-targeted biopsy of the prostate in a contemporary cohort

OBJECTIVE

To assess the added value of concurrent systematic randomised ultrasonography-guided biopsy (SBx) to multiparametric magnetic resonance imaging (mpMRI)-targeted biopsy and the additional rate of overdiagnosis of clinically insignificant prostate cancer (ciPCa) by SBx in a large contemporary, real-world cohort.

PATIENTS AND METHODS

A total of 1552 patients with positive mpMRI and consecutive mpMRI-targeted biopsy and SBx were enrolled. Added value and the rate of overdiagnosis by SBx was evaluated.

PRIMARY OUTCOME

added value of SBx, defined as detection rate of clinically significant PCa (csPCa; International Society of Urological Pathology [ISUP] Grade ≥2) by SBx, while mpMRI-targeted biopsy was negative or showed ciPCa (ISUP Grade 1).

SECONDARY OUTCOME

rate of overdiagnosis by SBx, defined as detection of ciPCa in patients with negative mpMRI-targeted biopsy and PSA level of <10 ng/mL.

RESULTS

Detection rate of csPCa by mpMRI-targeted biopsy and/or SBx was 753/1552 (49%). Added value of SBx was 145/944 (15%). Rate of overdiagnosis by SBx was 146/656 (22%). Added value of SBx did not change when comparing patients with previous prostate biopsy and biopsy naïve patients. In multivariable analysis, a Prostate Imaging-Reporting and Data System (PI-RADS) 4 index lesion (odds ratio [OR] 3.19, 95% confidence interval [CI] 1.66-6.78; P = 0.001), a PI-RADS 5 index lesion (OR 2.89, 95% CI 1.39-6.46; P = 0.006) and age (OR 1.05, 95% CI 1.03-1.08; P < 0.001) were independently associated with added value of SBx.

CONCLUSIONS

In our real-world analysis, we saw a significant impact on added value and added rate of overdiagnosis by SBx. Subgroup analysis showed no significant decrease of added value in any evaluated risk group. Therefore, we do not endorse omitting concurrent SBx to mpMRI-guided biopsy of the prostate.

Key learnings from concordant systematic biopsies in prostate-specific membrane antigen positron emission tomography/computed tomography-guided prostate biopsies: Enhancing targeting accuracy

BACKGROUND

Prostate cancer (PCa) diagnosis and staging have evolved with the advent of 68Ga-Prostate-specific membrane antigen positron emission tomography/computed tomography (PSMA-PET/CT). This study investigates the role of complementary systematic biopsies (SB) during PSMA-PET/CT-guided targeted prostate biopsies (PET-TB) for PCa detection, grading, and distribution. We address the uncertainty surrounding the necessity of SB in conjunction with PET-TB.

METHODS

We analyzed PCa grading and distribution in 30 men who underwent PET-TB and SB because of contraindication to magnetic resonance imaging or high clinical suspicion of PCa. Tumor distribution was assessed in relation to the PET-highlighted lesions. Standardized reporting schemes, encompassing SUVmax , PRIMARY score, and miTNM classification, were evaluated.

RESULTS

80% of patients were diagnosed with PCa, with 70% classified as clinically significant (csPCa). SB detected more csPCa cases than PET-TB, but the differences were not statistically significant. Discordant results were observed in 25% of cases, where SB outperformed PET-TB. Spatial analysis revealed that tumor-bearing cores from SB were often located in close proximity to the PET-highlighted region. Reporting schemes showed potential for csPCa detection with significantly increased SUVmax in csPCA patients. Subsequent follow-up data underscored the importance of SB in precise PCa grading and staging.

CONCLUSIONS

While PET-TB can simplify prostate biopsy and reduce invasiveness by core number, SB cannot be omitted yet due to potential PET-TB targeting errors. Factors such as limited spatial resolution and fusion inaccuracies contribute to the need for SB. Standardization in reporting schemes currently cannot compensate for targeting errors highlighting the need for refinement.

Is imaging accurate enough to detect index lesion in prostate cancer? Analysis of the performance of MRI and other imaging modalities

Prostate imaging techniques have progressed across the years allowing for a better detection and characterization of prostate cancer (PCa) lesions. These advancements have led to the possibility to also improve and tailor the treatments on the most aggressive lesion, defined as Index Lesion (IL), to reduce morbidity. The IL is, indeed, considered as the entity which encompass the most aggressive features in prostate cancer disease. Multiparametric magnetic resonance imaging (mpMRI) has emerged as the suggested tool to detect the disease and plan treatments, including those under investigation such as focal therapy (FT). Our review aimed to query the literature on the ability of mpMRI in IL detection and to explore the future perspectives in PCa IL diagnosis. A review of the literature was performed from January 2010 to July 2023. All studies investigating the performance of mpMRI and other main imaging techniques able to detect the IL were assessed and evaluated. mpMRI performs well in the detection of IL with a sensitivity which reaches 71% to 94% among the different studies. However, mpMRI seems to have limited sensitivity in the detection of small tumours (<0.5 mL) and low-grade histology lesions. To overcome these limitations other diagnostic imaging techniques have been proposed. Multiparametric Ultrasound has shown results comparable to mpMRI while detecting 4.3% fewer clinically significant PCa (P=0.042). Positron emission tomography-based modalities using PSMA seems to have higher sensitivity than mpMRI, being able to yield from 13.5% to 18.2% additional cancers. MRI has emerged as the recommended tool since most of the IL can be easily identified, and is the imaging of choice while selecting patients for FT. Other imaging modalities has been proposed to improve PCa lesions detection, but results need to be confirmed by ongoing randomized controlled trial.

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.

The Impact of Prostate Volume on the Prostate Imaging and Reporting Data System (PI-RADS) in a Real-World Setting

Multiparametric magnetic resonance imaging (mpMRI) has emerged as a new cornerstone in the diagnostic pathway of prostate cancer. However, mpMRI is not devoid of factors influencing its detection rate of clinically significant prostate cancer (csPCa). Amongst others, prostate volume has been demonstrated to influence the detection rates of csPCa. Particularly, increasing volume has been linked to a reduced cancer detection rate. However, information about the linkage between PI-RADS, prostate volume and detection rate is relatively sparse. Therefore, the current study aims to assess the association between prostate volume, PI-RADS score and detection rate of csP-Ca, representing daily practice and contemporary mpMRI expertise. Thus, 1039 consecutive patients with 1151 PI-RADS targets, who underwent mpMRI-guided prostate biopsy at our tertiary referral center, were included. Prior mpMRI had been assessed by a plethora of 111 radiology offices, including academic centers and private practices. mpMRI was not secondarily reviewed in house before biopsy. mpMRI-targeted biopsy was performed by a small group of a total of ten urologists, who had performed at least 100 previous biopsies. Using ROC analysis, we defined cut-off values of prostate volume for each PI-RADS score, where the detection rate drops significantly. For PI-RADS 4 lesions, we found a volume > 61.5 ccm significantly reduced the cancer detection rate (OR 0.24; 95% CI 0.16-0.38; p < 0.001). For PI-RADS 5 lesions, we found a volume > 51.5 ccm to significantly reduce the cancer detection rate (OR 0.39; 95% CI 0.25-0.62; p < 0.001). For PI-RADS 3 lesions, none of the evaluated clinical parameters had a significant impact on the detection rate of csPCa. In conclusion, we show that enlarged prostate volume represents a major limitation in the daily practice of mpMRI-targeted biopsy. This study is the first to define exact cut-off values of prostate volume to significantly impair the validity of PI-RADS assessed in a real-world setting. Therefore, the results of mpMRI-targeted biopsy should be interpreted carefully, especially in patients with prostate volumes above our defined thresholds.