Imaging Assessment of Prostate Cancer Extra-Prostatic Extension: from histology to controversies

Prostate cancer (PCa) is the most common non-skin malignancy among men and the fourth leading cause of cancer-related deaths globally. Accurate staging of PCa, particularly the assessment of extra-prostatic extension (EPE), is critical for prognosis and treatment planning. EPE, typically evaluated using magnetic resonance imaging (MRI), is associated with higher risks of positive surgical margins, biochemical recurrence, metastasis, and reduced overall survival. Despite the widespread use of MRI, there is no consensus on diagnosing EPE via imaging. There are two main scores assessing EPE by MRI: the European Society of Urogenital Radiology (ESUR) score and an MRI-based EPE grading system from an American group. While both are widely recognized, their differences can lead to varying interpretations in specific cases. This paper clarifies the anatomical considerations in diagnosing locally advanced PCa, explores EPE's impact on treatment and prognosis, and evaluates the relevance of MRI findings according to different criteria. Accurate EPE diagnosis remains challenging due to MRI limitations and inconsistencies in interpretation. Understanding these variations is crucial for optimal patient management.

Does the extent of extraprostatic extension at radical prostatectomy predict outcome?-a systematic review and meta-analysis

Extraprostatic extension (EPE) of prostate cancer is usually reported as either focal (F-EPE) or established (E-EPE), but data on the implication for outcomes of this subdivision are conflicting and no systematic review (SR) evaluating this exists. This SR aims to address this gap in the literature, focusing on the impact of F-EPE and E-EPE on outcome in radical prostatectomy (RP) patients. Searches on Embase, Medline(R), and Pubmed databases were conducted. Studies were included if they investigated the extent of EPE in RP patients and correlated this with defined outcomes (biochemical recurrence [BCR], death, metastasis). Quality was assessed using the Newcastle-Ottawa Scale. A random effects model was used for studies reporting hazard ratios (EPE extent and biochemical recurrence). 24 studies, including 49,187 men, were included. Six studies were of high quality. 20 studies reported how they measured EPE. 13 studies reported that the extent of EPE was associated significantly with BCR. Meta-analysis showed there was a significant correlation between BCR and both F-EPE and E-EPE when compared to organ-confined disease; no significant difference was found between F-EPE and E-EPE. This is the only SR to investigate the extent of EPE on outcomes after RP. EPE alone predicts outcome, but the value of subdivision by extent could not be demonstrated. Comparisons are limited due to variability in EPE assessment and in the methods used to report outcomes in the literature. Further work to standardize EPE reporting methods, in larger cohorts, may be helpful to resolve remaining questions.

The Clinical Significance of Either Extraprostatic Extension or Microscopic Bladder Neck Invasion Alone Versus Both in Men With pT3a Prostate Cancer Undergoing Radical Prostatectomy: A Proposal for a New pT3a Subclassification

The prognosis of prostate cancers exhibiting extraprostatic extension [other than bladder or seminal vesicle invasion (EPE)] and/or microscopic bladder neck invasion (mBNI) is variable, and further risk stratification is required. We herein assessed radical prostatectomy findings and long-term oncologic outcomes in consecutive 957 patients with pT3a disease. The patient cohort was divided into 4 groups, focal EPE (F-EPE) only (n=177; 18.5%), nonfocal/established (E-EPE) only (n=634; 66.2%), mBNI only (n=51; 5.3%). The rate of positive surgical margin and estimated volume of tumor were significantly higher in patients with both EPE and mBNI than in those with either. In addition, compared with F-EPE or mBNI only, E-EPE only was significantly associated with higher Grade Group, lymph node metastasis, and larger tumor volume. Kaplan-Meier analysis revealed a comparable prognosis after prostatectomy between those showing F-EPE only versus mBNI only ( P =0.986), and these 2 cohorts were combined for further analysis. Then, patients showing E-EPE only had a significantly higher or lower risk of progression compared with those showing F-EPE or mBNI only ( P <0.001) or both EPE and mBNI ( P <0.001), respectively. These significant differences in progression-free survival were also seen in subgroups, including those with or without undergoing adjuvant therapy before recurrence and those showing no lymph node metastasis. In multivariate analysis, F-EPE or mBNI only (hazard ratio=0.524, P =0.003) or both EPE and mBNI (hazard ratio=1.465, P =0.039) (vs. E-EPE only) showed significance for progression. Based on these findings, we propose a novel pT3a subclassification, pT3a1 (F-EPE or mBNI alone), pT3a2 (E-EPE alone), and pT3a3 (both EPE and mBNI).

Revisiting extraprostatic extension based on invasion depth and number for new algorithm for substaging of pT3a prostate cancer

Extraprostatic extension (EPE) is a factor in determining pT3a stage in prostate cancer. However, the only distinction in EPE is whether it is focal or non-focal, causing diagnostic and prognostic ambiguity. We substaged pT3a malignancies using classification of EPE to improve personalized prognostication. We evaluated 465 radical prostatectomy specimens with a digital image analyzer by measuring the number, radial distance and two-dimensional square area of the EPE. The most significant cut-off value was proposed as an algorithm for the pT3a substaging system to predict biochemical recurrence (BCR). A combination of the radial distance and the number of EPEs predicted BCR the most effectively. The optimal cut-off criteria were 0.75 mm and 2 mm in radial distance and multifocal EPE (hazard ratio: 2.526, C-index 0.656). The pT3a was subdivided into pT3a1, < 0.75 mm and any number of EPEs; pT3a2, 0.75–2 mm and one EPE; and pT3a3, > 2 mm and any number of EPEs or 0.75–2 mm and ≥ 2 EPEs. This combined tier was highly significant in the prediction of BCR-free survival. The combination of radial distance and number of EPEs could be used to subdivide pT3a prostate cancer and may aid in the prediction of BCR.

Extraprostatic Tumor Extension: Comparison of Preoperative Multiparametric MRI Criteria and Histopathologic Correlation after Radical Prostatectomy

Background There are no standardized and well-validated criteria for assessing the risk of extraprostatic extension (EPE) of prostate cancer at preoperative multiparametric MRI. Purpose To compare diagnostic performance, intra- and interreader agreement, and correlations of MRI-based criteria for assessment of EPE after radical prostatectomy, including EPE grade, European Society of Urogenital Radiology (ESUR) score, Likert scale, and capsular contact length (CCL). Materials and Methods This retrospective study included consecutive men who underwent MRI and radical prostatectomy between July 2016 and March 2017. Two genitourinary radiologists independently estimated the probability of EPE by using four MRI-based scoring methods. The diagnostic accuracies and intra- and interobserver agreement were evaluated with area under the receiver operating characteristic curve (AUC) and κ statistics, respectively. Correlations between MRI-based score and histologic extent of EPE were analyzed by using the Spearman correlation coefficient (ρ). Results A total of 301 men (mean age ± standard deviation, 65 years ± 7) were evaluated. A total of 129 (42.9%) men had EPE. The AUC ranges of EPE grade, ESUR score, Likert scale, and CCL for assessment of EPE were 0.77-0.81, 0.79-0.81, 0.78-0.79, and 0.78-0.85, respectively, for the two readers. The Likert scale showed lower sensitivity (68.2% [88 of 129] for reader 1, 72.1% [93 of 129] for reader 2) than did EPE grade (77.5% [100 of 129] for reader 1, 79.8% [103 of 129] for reader 2; P ≤ .04). Intra- and interreader agreement were substantial (κ range, 0.61-0.74) for the four methods, with ESUR score showing the lowest values (κ = 0.61 and κ = 0.63, respectively). EPE grade showed highest correlation with histologic extent of EPE (ρ = 0.53 and ρ = 0.55 for circumferential length; ρ = 0.42 and ρ = 0.55 for radial length for readers 1 and 2, respectively; P < .001). Conclusion Extraprostatic extension (EPE) grade, European Society of Urogenital Radiology score, Likert scale, and capsular contact length showed good overall diagnostic performance; however, the EPE grade resulted in more reliable performance and had the highest correlation with histologic EPE extent. © RSNA, 2020 Online supplemental material is available for this article. See also the editorial by Padhani and Petralia in this issue.

Determining the cut-off values of tumor diameter, degree of extraprostatic extension, and extent of surgical margin positivity with regard to biochemical recurrence of prostate cancer after radical prostatectomy

BACKGROUND

The pre-biopsy (bx) prostate-specific antigen (PSA) level, tumor volume/diameter, degree of extraprostatic extension (EPE), and extent of surgical margin positivity have been shown to be significant prognostic parameters of biochemical recurrence (BCR) after radical prostatectomy. The present study assessed the cut-off values of the pre-bx PSA level, maximum tumor diameter, radial and circumferential distances of EPE, and circumferential length of surgical margin (SM) positivity with regard to BCR.

MATERIAL AND METHODS

The study included 445 radical prostatectomy specimens, and the cut-off values of all parameters were determined using receiver operating characteristic curve analysis.

RESULTS

An ISUP grade group ≥ 3, radial distance of EPE >1 mm, and circumferential length of SM positivity ≥2 mm were identified as independent predictors of BCR after radical prostatectomy. The parameters that showed statistical significance in univariate analysis, such as pre-bx PSA level ≥ 7.20 ng/mL, tumor diameter ≥ 19.5 mm, presence of seminal vesicle invasion, and circumferential distance of EPE >3 mm, did not have independent prognostic values for BCR.

CONCLUSIONS

An ISUP grade group ≥ 3, radial distance of EPE >1 mm, and circumferential length of SM positivity ≥2 mm are predictors of BCR. Our findings might have significance in risk classification and adjuvant therapy consideration among patients with localized prostate cancer.

Prostate cancer reporting and staging: needle biopsy and radical prostatectomy specimens

Prostatic adenocarcinoma remains the most common cancer affecting men. A substantial majority of patients have the diagnosis made on thin needle biopsies, most often in the absence of a palpable abnormality. Treatment choices ranging from surveillance to radical prostatectomy or radiation therapy are largely driven by the pathologic findings in the biopsy specimen. The first part of this review focuses on important morphologic parameters in needle biopsy specimens that are not covered in the accompanying articles. This includes tumor quantification as well as other parameters such a extraprostatic extension, seminal vesicle invasion, perineural invasion, and lymphovascular invasion. For those men who undergo radical prostatectomy, pathologic stage and other parameters are critical in prognostication and in determining the appropriateness of adjuvant therapy. Staging parameters, including extraprostatic extension, seminal vesicle invasion, and lymph node status are discussed here. Surgical margin status is also an important parameter and definitions and reporting of this feature are detailed. Throughout the article the current reporting guidelines published by the College of American Pathologists and the International Collaboration on Cancer Reporting are highlighted.

Impact of the extent of extraprostatic extension defined by Epstein's method in patients with negative surgical margins and negative lymph node invasion

BACKGROUND

To assess the impact of the degree of extraprostatic extension (EPE) on biochemical recurrence (BCR) and utility of the original Epstein's criteria to define EPE in a cohort of pT3aN0 without positive surgical margin (PSM).

METHODS

A two-center retrospective analysis was performed on data from 490 pT3aN0 patients who underwent radical prostatectomy between 2000 and 2012. Patients with neoadjuvant and/or adjuvant therapy, detectable PSA and PSM were excluded. Our pathologists used Epstein's criteria to report the degree of EPE. When pathology reports did not reflect the terms 'focal' or 'established' (non-focal), slides were analyzed by a single genitourinary pathologist for final evaluation. The end point was defined by BCR.

RESULTS

Selection criteria yielded 247 patients. Mean follow-up was 56.3±4.6 months; mean age at surgery was 62.5 years. Sixty-one (24.7%) patients experienced BCR during follow-up. Patients with focal extension had a 5-year recurrence-free survival of 89% versus 80% for those with non-focal extension (P=0.0018). In multivariate analysis, both pathologic Gleason score (hazard ratio 2.5; 95% confidence interval 1.4-4.5; P=0.002) and the extent of EPE (hazard ratio 1.8; 95% confidence interval 1.1-3.5; P=0.029) were significant predictors of BCR.

CONCLUSIONS

The extent of EPE is an independent predictor of BCR in pT3aN0 prostate cancer without PSM. This study reinforces the utility of the subjective Epstein approach already adopted by most pathologists for quantification of the extent of EPE.

ERG rearrangement as a novel marker for predicting the extra-prostatic extension of clinically localised prostate cancer

Currently, there are no well-established preoperative clinicopathological parameters for predicting extra-prostatic extension (EPE) in patients with clinically localised prostate cancer (PCa). The transmembrane protease serine 2 (TMPRSS2)-ETS-related gene (ERG) fusion gene is a specific biomarker of PCa and is considered a prognostic predictor. The aim of the present study was to assess the value of this marker for predicting EPE in patients with clinically localised PCa. In total, 306 PCa patients with clinically localised disease, including 220 patients (71.9%) with organ-confined disease and 86 EPE cases (28.1%), were included in the study. Receiver operating characteristic curves and logistic regression were employed to establish the optimal cut-off value and to investigate whether ERG rearrangement was an independent predictor for the EPE of clinically localised PCa. A leave-one-out cross-validation (LOOCV) model was implemented to validate the predictive power of ERG rearrangement. An increase in ERG rearrangements was identified to be associate'd with EPE, and the optimal cut-off for predicting EPE was determined to be 2.25%, with a sensitivity of 70.24% [95% confidence interval (CI), 62.6-78.9%], a specificity of 80.43% (95% CI, 75.4-85.1%), and an area under the curve (AUC) of 0.781 (95% CI, 0.730-0.826). In the LOOCV model, ERG rearrangement also demonstrated good performance for predicting EPE (sensitivity, 76.923%; specificity, 71.429%; 95% CI for AUC, 0.724-0.958). In addition, a high Gleason score (≥7) and a cT2c classification upon biopsy were independent factors for EPE.

The Significance of Accurate Determination of Gleason Score for Therapeutic Options and Prognosis of Prostate Cancer

The Gleason score (GS) to date remains one of the most reliable prognostic predictors in prostate cancer (PCa). However, the majority of studies supporting its prognostic relevance were performed prior to its modification by the International Society of Urological Pathology (ISUP) in 2005. Furthermore, the combination of Gleason grading and nuclear/nucleolar subgrading (Helpap score) has been shown to essentially improve grading concordance between biopsy and radical prostatectomy (RP) specimens. This prompted us to investigate the modified GS and combigrading (Gleason/Helpap score) in association with clinicopathological features, biochemical recurrence (BCR), and survival. Core needle biopsies and corresponding RP specimens from 580 patients diagnosed with PCa between 2005 and 2010 were evaluated. According to the modified GS, the comparison between biopsy and RP samples resulted in an upgrading from GS 6 to GS 7a and GS 7b in 65% and 19%, respectively. Combigrading further resulted in an upgrading from low grade (GS 6/2a) to intermediate grade PCa (GS 6/2b) in 11.1% and from intermediate grade (GS 6/2b) to high grade PCa (GS 7b/2b) in 22.6%. Overall, well-differentiated PCa (GS 6/2a) was detected in 2.8% of RP specimens, while intermediate grade (GS 6/2b and GS 7a/2b) and high grade cancers (≥ GS 7b) accounted for 39.5% and 57.4% of cases, respectively. At a mean follow-up of 3.9 years, BCR was observed in 17.6% of patients with intermediate (9.8%) or high grade PCa (30.2%), while PSA relapse did not occur in GS 6/2a PCa. In conclusion, adding nuclear/nucleolar subgrading to the modified GS allowed for a more accurate distinction between low and intermediate grade PCa, therefore offering a valuable tool for the identification of patients eligible for active surveillance (AS).

Variation between specialist uropatholgists in reporting extraprostatic extension after radical prostatectomy

Aims

Extraprostatic extension of prostate cancer in radical prostatectomy specimens significantly affects patient management. We evaluated the degree of interobserver variation between uropathologists at a tertiary referral teaching hospital in assessing the extraprostatic extension of prostate cancer in radical prostatectomy specimens.

Methods

Histopathological data from a consecutive series of 293 radical prostatectomy specimens (January 2007–December 2012) were reviewed. A subset of 50 consecutive radical prostatectomy cases originally staged as tumours confined to the prostate (pT2) or tumours extending into periprostatic tissue (pT3a) during this period were reviewed by four specialist uropathologists.

Results

Five consultant histopathologists reported these specimens with significant differences in the reported stage (p=0.0164) between pathologists. Double-blind review by 4 uropathologists of 50 consecutive radical prostatectomy cases showed a lack of consensus in 16/50 (32%) cases (κ score 0.58, moderate agreement). A consensus meeting was held, but consensus could still not be reached in 9/16 cases.

Conclusions

Our findings highlight variability in the reporting of pT stage in radical prostatectomy specimens even by specialist uropathologists. Assessment of extraprostatic extension has important implications for patient management and there is a need for more precise guidance.

Prognostic significance of histopathological features of extraprostatic extension of prostate cancer

AIMS

The 2009 International Society of Urological Pathology consensus conference recommended reporting the extent of extraprostatic extension (EPE) for the prediction of outcome in prostate cancer. Our aim was to stratify EPE into prognostic groups.

METHODS AND RESULTS

We reviewed 1051 radical prostatectomy (RP) specimens from 1998 to 2005. EPE was classified according to the extent, laterality and presence of perineural invasion (PNI) at the site of EPE. Cox regression was used to explore associations with biochemical recurrence. EPE was observed in 470 cases (44.7%), and predicted a higher progression rate than for organ-confined cancer [hazard ratio (HR) 1.4, 95% confidence interval (CI) 1.1-1.8, P = 0.007]. Focal versus established EPE according to Epstein (HR 2.0, 95% CI 1.1-3.5, P = 0.027) and Wheeler (HR 2.2, 95% CI 1.2-3.9, P = 0.010), and the radial distance of EPE dichotomized by the median (1.1 mm) (HR 1.5, 95% CI 1.1-2.2, P = 0.015), were all predictive of recurrence; but PNI at the site of EPE, circumferential length of EPE, number of sections and foci with EPE, and bilateral versus unilateral EPE were not.

CONCLUSIONS

The radial extent of EPE predicts recurrence after RP, but circumferential extent, PNI at the site of EPE, number of sections or foci of EPE, and laterality do not. If validated, the proposed radial extent method may allow for more reproducible quantitation of EPE.

The heterogeneous Gleason 7 carcinoma of the prostate: analyses of low and high grade (risk) carcinomas with criteria of the International Society of Urological Pathology (ISUP)

Prostate carcinoma (PCa) with Gleason score (GS) 7 has to be examined differentially regarding its prognosis. Using the criteria of ISUP and supplementations, we attempted to analyze the heterogeneity of PCa with GS 7 of biopsy and corresponding specimens of radical prostatectomies (RP). PCa of 530 patients were graded according to Gleason under additional consideration of the state of the nucleoli. Investigating the biopsy specimens, we determined the pattern of Gleason 4 of GS 7, the extension of the tumors in percent, and the number of biopsies containing tumor. In the corresponding specimens of RP, the grading and the state of TNM with margins were assessed. Carcinomas with GS 7 (4+3) in biopsy and RP specimens were unequivocally assigned to the group of high-grade tumors. Carcinomas with GS 7 (3+4) were significantly different from carcinomas with GS 6 when only few and small nucleoli in GS 6 were present (low grade type, p≤0.0001), but were similar to the GS 6 group when nucleoli were prominent (intermediary type, p=0.71). The intermediary group showed an upgrading rate of 36% from GS 6 to GS 7. Furthermore the correlation between organ-confined and non-organ-confined growth showed differences of 63% and 37% in the intermediary group (p=0.0001). The values of grading, staging, margins and metastases indicate that carcinomas of the prostate with the Gleason 3+4 pattern correspond to an intermediary group of carcinomas in contrast to high-grade (high risk) carcinomas with GS 7 and pattern 4+3.