Prostate cancer management choices in patients undergoing multiparametric magnetic resonance imaging/ultrasound fusion biopsy compared to systematic biopsy

Diagnosis and Pathologic Reporting of Prostate Cancer in the Era of MRI-Targeted Prostate Biopsy

Historically, the detection of prostate cancer relied upon a systematic yet random sampling of the prostate by transrectal ultrasound guided biopsy. This approach was a nontargeted technique that led to the under detection of cancers at biopsy and the upgrading of cancers at radical prostatectomy. Multiparametric MRI-targeted prostate biopsy allows for an image-directed approach to the identification of prostate cancer. MRI-targeted biopsy of the prostate is superior for the detection of clinically significant prostate cancer. As this technique has become more prevalent among urologists, pathologists need to recognize how this development impacts cancer diagnosis and reporting.

Cancer-specific outcomes for prostate cancer patients who had prebiopsy prostate MRI

PURPOSE

We characterized population-level cancer-specific outcomes for prostate cancer patients based on use of prebiopsy prostate MRI.

METHODS

Using SEER-Medicare claims, we identified men diagnosed with localized prostate cancer from 2010-2015 and prostate-specific antigen (PSA) < 20 ng/mL. Primary exposure was prebiopsy prostate MRI prior to diagnosis (i.e., CPT 72197 linked to urology-specific diagnosis). Outcomes included diagnosis of Grade Group 2+ disease on biopsy and proportion treated with prostatectomy. We assessed those treated with prostatectomy and evaluated association with prebiopsy MRI and grade concordance between biopsy and prostatectomy. We estimated adjusted odds ratios with multivariable regression after accounting for other factors (e.g., age, year, PSA, race/ethnicity).

RESULTS

We identified 48,574 patients, where 915 (1.9%) underwent prebiopsy MRI. Patients with prebiopsy MRI had more GG>2 cancer on biopsy (70.0% MRI vs. 62.8% no MRI) but lost significance after adjustment (OR 1.12, 95% CI 0.96-1.30). Patients with prebiopsy MRI were more likely to have prostatectomy (39.2% vs. 28.5%, adjusted OR 1.51, 95%CI 1.31-1.76). Downgrading from biopsy GG 3-5 to final GG 1-2 was less common after prebiopsy MRI (21.3% vs. 28.2% no MRI, P = 0.05) but not significant after adjustment (OR 0.74, 95% CI 0.51 - 1.08). Among 14,027 men with prostatectomy, accurate risk classification was not more likely with a prebiopsy MRI (48.0% no MRI vs. 49.6% prebiopsy MRI, P = 0.56).

CONCLUSION

During initial adoption, men with prebiopsy prostate MRI had marginally increased detection of significant cancer on biopsy and were more likely to be treated with prostatectomy. For those treated with prostatectomy, use of prebiopsy MRI was not associated with a greater likelihood of accurate risk classification or grade concordance between biopsy and final pathology results.

Integration of magnetic resonance imaging into prostate cancer nomograms

The decision whether to undergo prostate biopsy must be carefully weighed. Nomograms have widely been utilized as risk calculators to improve the identification of prostate cancer by weighing several clinical factors. The recent inclusion of multiparametric magnetic resonance imaging (mpMRI) findings into nomograms has drastically improved their nomogram's accuracy at identifying clinically significant prostate cancer. Several novel nomograms have incorporated mpMRI to aid in the decision-making process in proceeding with a prostate biopsy in patients who are biopsy-naïve, have a prior negative biopsy, or are on active surveillance. Furthermore, novel nomograms have incorporated mpMRI to aid in treatment planning of definitive therapy. This literature review highlights how the inclusion of mpMRI into prostate cancer nomograms has improved upon their performance, potentially reduce unnecessary procedures, and enhance the individual risk assessment by improving confidence in clinical decision-making by both patients and their care providers.

MR-Guided High-Intensity Directional Ultrasound Ablation of Prostate Cancer

PURPOSE OF REVIEW

The goal of this paper was to review the novel treatment modality of high-intensity transurethral directional ultrasound for prostate cancer.

RECENT FINDINGS

Prostate cancer is a heterogeneous disease with some patients electing for active surveillance and focal therapies instead of definitive treatment with radical prostatectomy or radiation therapy. Prostate MRI has become a cornerstone of prostate cancer diagnosis, targeted biopsy, and treatment planning. Transurethral high-intensity directional ultrasound allows for MRI-guided ablation of the prostate gland with the ability to contour boundaries and spare critical structures, such as the neurovascular bundle and urinary sphincter. Although results are still emerging, this may offer patients a new option for focal therapy with a favorable side-effect profile. High-intensity transurethral directional ultrasound is an emerging treatment modality for both whole-gland and focal ablation with promising early results. Further research is needed to establish safety, tolerability, and long-term oncologic outcomes.

The accuracy of prostate lesion localization in cognitive fusion

PURPOSE

Prostate cancer (PCa) is one of the most common cancers in elderly men worldwide. Systematic biopsy guided by transrectal ultrasound remains the standard for PCa diagnosis; however, the false negative rate is 10-20%. Multiparametric magnetic resonance imaging (mpMRI) allows PCa visualization with a more precise localization and a higher accuracy and specificity for the detection of PCa. The physician can mentally relocate the most appropriate area detected on the prebiopsy mpMRI, based on its zonal topography and anatomical landmarks, called cognitive fusion. Herein, we concentrated on the accuracy of PCa localization in cognitive fusion compared with MRI-TRUS fusion and explored the applied scope of cognitive fusion.

METHODS

Thirty-two eligible patients with 36 PCa lesions were recruited for our study. TRUS examinations and MRI-TRUS fusion procedures were performed by experienced operators. The cognitive fusion images were compared using the TRUS image in a MRI-TRUS fusion workstation.

RESULTS

Using cognitive fusion imaging, 86.1% of the lesions were accurately located by the senior sonographer and 69.4% of the lesions were accurately located by the junior sonographer. The maximum diameter and PI-RADS score of the lesions were important factors that affected the accuracy of cognitive fusion (P < 0.05). Furthermore, the lesions with high PI-RADS scores and the lesions with large diameters were more accurately located using cognitive fusion (P < 0.05).

CONCLUSIONS

Cognitive fusion is a reliable technique with dependency on working experience, and its accuracy of locating suspicious lesions is consistent with MRI-TRUS fusion in patients with high PI-RADS score and large lesions.

Evaluation of MSKCC Preprostatectomy nomogram in men who undergo MRI-targeted prostate biopsy prior to radical prostatectomy

INTRODUCTION

The Memorial Sloan Kettering Cancer Center (MSKCC) Preprostatectomy nomogram is a widely used resource that integrates clinical factors to predict the likelihood of adverse pathology at radical prostatectomy. Adoption of magnetic resonance imaging targeted biopsy (TB) permits optimized detection of clinically-significant cancer over systematic biopsy (SB) alone. We aim to evaluate the prognostic utility of the MSKCC Preprostatectomy nomogram with TB pathology results.

METHODS

Men who underwent SB and magnetic resonance imaging TB who later underwent radical prostatectomy at our institution were included. Patient information was entered into the MSKCC Preprostatectomy nomogram using 5 biopsy reporting schemes with TB reported by both individual core (IC) and aggregate group (AG) methods. The likelihood of extraprostatic extension, seminal vesicle invasion, and lymph node involvement as predicted by the nomogram for each biopsy reporting schema were compared to radical prostatectomy pathology.

RESULTS

We identified 63 men from January 2014 to November 2017. On receiver operating characteristic analysis, IC-TB, AG-TB, SB plus IC-TB, and SB plus AG-TB exhibited similar, if not improved, area under the curve compared to SB alone in predicting extraprostatic extension (0.671, 0.674, 0.658, and 0.6613 vs. 0.6085). This was similarly observed for seminal vesicle invasion prediction using SB plus IC-TB compared to SB alone (0.727 vs. 0.733). For lymph node involvement, superior but nonsignificant area under the curve was observed for AG-TB (0.647) compared to IC-TB (0.571) and SB alone (0.524) CONCLUSIONS: Using TB pathology results either alone or combined with SB pathology results as input to the MSKCC Preprostatectomy nomogram appears comparable for prognosticating adverse pathology on radical prostatectomy compared to SB alone, but robust validation is warranted prior to adoption into clinical practice.

Focused Submission of Tissue for Radical Prostatectomy Following Multiparametric Magnetic Resonance Imaging/Ultrasound Fusion-Targeted Biopsy

Prostate cancer can be difficult to appreciate grossly and therefore partial sampling of the gland can lead to incorrect grading, staging, or margin status. However, submitting the entire prostate is more time consuming and costly. We investigated the use of magnetic resonance imaging/ultrasound-targeted biopsy for the selective submission of prostatectomy specimens. We performed a retrospective review for patients with cancer on targeted prostate biopsy who underwent subsequent radical prostatectomy. Prostatectomy specimens were submitted in their entirety and assessed for Grade Group, extraprostatic extension (EPE), margins, and number of blocks. For Targeted-Grossing (TG) assessment, apex margin, bladder neck margin, seminal vesicles, and vas deferens sections were included. For the remainder of the prostate, only sections from areas shown to be positive for cancer on targeted biopsy were included in the analysis. With total tissue submission, EPE was found in 39/81 (48.1%) cases and positive margins in 19/81 (23.5%) cases. The TG method required significantly fewer blocks: 15.8 ± 5.9 versus 44.9 ± 11.9 (P < .0001). The TG method would have diagnosed the correct stage in 73/81 (90.1%) cases, Grade Group in 74/81 (91.4%) cases, and margin status in 79/81 (97.5%) cases. EPE was missed completely by the TG method in 7 cases (P = .008), of which 5/7 (71.4%) had focal EPE. There was no significant difference in stage (P = .24), Grade Group (P = .95), or margin status (P = .16) between the 2 methods. Grossing utilizing selective tissue submission from areas found to be positive for prostate cancer on magnetic resonance imaging/ultrasound-targeted prostate biopsy remains inferior to complete submission of tissue for radical prostatectomy specimens.

PTEN and ERG detection in multiparametric magnetic resonance imaging/ultrasound fusion targeted prostate biopsy compared to systematic biopsy

Multiparametric magnetic resonance imaging (MRI)/ultrasound fusion targeted prostate biopsy has been shown to outperform systematic biopsy in the detection of clinically significant prostate cancer. Aside from tumor grade, tumor biomarkers such as phosphatase and tensin homolog (PTEN) and ETS-related gene (ERG) have prognostic significance in prostate cancer and may help direct management of patients with low-grade tumors. Our objective was to compare the detection of PTEN and ERG expression in MRI-targeted versus systematic prostate biopsies. We compared immunohistochemical expression for PTEN and ERG on prostate biopsy cores from patients with Grade Group (GG) 1 or GG2 prostate cancer who had undergone systematic biopsy with concurrent targeted biopsy. Fifty-three cases had both systematic and MRI-targeted prostate tissue available for staining for PTEN; and 52 cases, for ERG. ERG positivity was seen in 37/52 (71.2%) cases, and PTEN loss was seen in 15/53 (28.3%) cases. The detection of ERG expression was not significantly different between MRI-targeted and systematic biopsy (P = .4). Targeted biopsy was superior to systematic biopsy in the detection of PTEN loss (P = .02). MRI-targeted cores detected 14/15 (93.3%) cases of PTEN loss compared to 7/15 (46.7%) cases detected by systematic cores. Most cases with PTEN loss showed heterogeneous expression in both systematic and targeted cores. In 14/15 (93.3%) cases with PTEN loss, GG was the same between targeted and systematic biopsy. Targeted biopsy is superior to systematic biopsy in the detection of PTEN loss in GG1 and GG2 tumors. Inclusion of targeted cores may be helpful for evaluation of certain prognostic biomarkers.

Imaging as a Personalized Biomarker for Prostate Cancer Risk Stratification

Biomarkers provide objective data to guide clinicians in disease management. Prostate-specific antigen serves as a biomarker for screening of prostate cancer but has come under scrutiny for detection of clinically indolent disease. Multiple imaging techniques demonstrate promising results for diagnosing, staging, and determining definitive management of prostate cancer. One such modality, multiparametric magnetic resonance imaging (mpMRI), detects more clinically significant disease while missing lower volume and clinically insignificant disease. It also provides valuable information regarding tumor characteristics such as location and extraprostatic extension to guide surgical planning. Information from mpMRI may also help patients avoid unnecessary biopsies in the future. It can also be incorporated into targeted biopsies as well as following patients on active surveillance. Other novel techniques have also been developed to detect metastatic disease with advantages over traditional computer tomography and magnetic resonance imaging, which primarily rely on defined size criteria. These new techniques take advantage of underlying biological changes in prostate cancer tissue to identify metastatic disease. The purpose of this review is to present literature on imaging as a personalized biomarker for prostate cancer risk stratification.

Rethinking active surveillance for prostate cancer in African American men

Active surveillance (AS) is a treatment modality for prostate cancer that aims to simultaneously avoid overtreatment and allow for the timely intervention of localized disease. AS has become the de facto standard of care for most men with low-risk prostate cancer. However, few African American (AA) men were included in the prospective observational cohorts that resulted in a paradigm shift in treatment recommendations from active intervention toward AS. It has been established that AA men have an increased prostate cancer incidence, higher baseline prostate-specific antigen (PSA) values, more aggressive prostate cancer features, greater frequency of biochemical recurrence after treatment, and higher overall cancer-specific mortality compared to their Caucasian counterparts. As such, this has given many physicians pause before initiating AS for AA patients. In the following manuscript, we will review the available literature regarding AS, with a particular focus on AA men. The preponderance of evidence demonstrates that AS is as viable a management method for AA with low-risk prostate cancer as it is with other racial groups.