Does Discontinuous Involvement of a Prostatic Needle Biopsy Core by Adenocarcinoma Correlate With a Large Tumor Focus at Radical Prostatectomy?

Cumulative cancer locations on prostate biopsy and active surveillance outcomes in the MRI era

BACKGROUND

To validate the use of a cumulative cancer locations (CCLO) score, a measurement of tumor volume on biopsy, and to develop a novel magnetic resonance imaging (MRI)-informed CCLO (mCCLO) score to predict clinical outcomes on active surveillance (AS).

METHODS

The CCLO score is a sum of uniquely involved sextants with prostate cancer on diagnostic + confirmatory biopsy. The mCCLO score incorporates MRI findings into the CCLO score. Participants included 1284 individuals enrolled on AS between 1994 and 2022, 343 of whom underwent prostate MRI. The primary outcome was grade reclassification (GR) to grade group ≥2 disease; the secondary outcome was receipt of definitive treatment.

RESULTS

Increasing CCLO and mCCLO risk groups were associated with higher risk of GR and undergoing definitive treatment (both p < 0.001). On multivariable analysis, increasing mCCLO score was associated with higher risk of GR and receipt of definitive treatment (hazard ratios [HRs] per 1-unit increase: 1.26 [95% confidence interval [CI]: 1.12-1.41] and 1.21 [95% CI: 1.07-1.36], respectively). The model using mCCLO score to predict GR (c-index: 0.671; 95% CI: 0.621-0.721) performed at least as well as models using the number of cores positive for cancer (0.664 [0.613-0.715]; p = 0.7) and the maximum percentage of cancer in a core (0.641 [0.585-0.696]; p = 0.14).

CONCLUSIONS

The CCLO score is a valid, objective metric to predict GR and receipt of treatment in a large AS cohort. The ability of the MRI-informed mCCLO to predict GR is on par with traditional metrics of tumor volume but is more descriptive and may benefit from greater reproducibility. The mCCLO score can be implemented as a shorthand, informative tool for counseling patients about whether to remain on AS.

Measuring cancer burden in prostatic needle core biopsies: simplified assessments outperform complex measurements in assessing outcome: evidence to assist pathologist efficiency and minimize datasets

AIMS

The optimal method of measuring cancer extent in prostate cancer (PCa) biopsies is unknown.

METHODS AND RESULTS

Nine hundred eighty-one men with clinically localised PCa managed conservatively were reviewed with follow up. The number of positive cores (NPC), the Maximum Cancer Length in a core (MCL), Total Cancer Length (TCL), and percentage of positive cores (%+cores) was calculated and univariate and multivariate analysis performed using prostate-specific antigen (PSA), T-stage, and Gleason score. The presence of stromal gaps (SG) was recorded. Univariate models were run where SG made a difference to the MCL. All variables showed significant association with PCa death in univariate models. In multivariate models, incorporating PSA, T-stage, and Gleason score, only %+cores was a significant predictor of outcome, with a 10% increase in %+cores resulting in a hazard ratio (HR) of 1.07 (likelihood-ratio test P > Χ2  = 0.01). There were 120 patients where SG made a difference to the MCL and a total of 20 events in this group. Including SG, on univariate analysis the median MCL was 10 mm and HR was 1.16 (P = 0.007), not including SG, the median MCL was 6 mm and HR was 1.23 (P = 6.3 × 10-4 ). Inclusion or exclusion of SG made no significant difference to TCL as a predictor of outcome.

CONCLUSION

Cancer extent is a strong predictor of PCa death but only %+cores added to the multivariate model. Expressed as a fraction of NPC/total number of cores, this is the simplest method of assessment, which we favour over more complicated methods in nontargeted biopsies.

Biopsy-Integrated 3D Magnetic Resonance Imaging Modeling of Prostate Cancer and Its Application for Gleason Grade and Tumor Laterality Assessment

CONTEXT.—

Grade Group assessed using Gleason combined score and tumor extent is a main determinant for risk stratification and therapeutic planning of prostate cancer.

OBJECTIVE.—

To develop a 3-dimensional magnetic resonance imaging (MRI) model regarding Grade Group and tumor extent in collaboration with uroradiologists and uropathologists for optimal treatment planning for prostate cancer.

DESIGN.—

We studied the data from 83 patients with prostate cancer who underwent multiparametric MRI and subsequent MRI-transrectal ultrasound fusion biopsy and radical prostatectomy. A 3-dimensional MRI model was constructed by integrating topographic information of MRI-based segmented lesions, biopsy paths, and histopathologic information of biopsy specimens. The multiparametric MRI-integrated Grade Group and laterality were assessed by using the 3-dimensional MRI model and compared with the radical prostatectomy specimen.

RESULTS.—

The MRI-defined index tumor was concordant with radical prostatectomy in 94.7% (72 of 76) of cases. The multiparametric MRI-integrated Grade Group revealed the highest agreement (weighted κ, 0.545) and a significantly higher concordance rate (57.9%) than the targeted (47.8%, P = .008) and systematic (39.4%, P = .01) biopsies. The multiparametric MRI-integrated Grade Group showed significantly less downgrading rates than the combined biopsy (P = .001), without significant differences in upgrading rate (P = .06). The 3-dimensional multiparametric MRI model estimated tumor laterality in 66.2% (55 of 83) of cases, and contralateral clinically significant cancer was missed in 9.6% (8 of 83) of cases. The tumor length measured by multiparametric MRI best correlated with radical prostatectomy as compared with the biopsy-defined length.

CONCLUSIONS.—

The 3-dimensional model incorporating MRI and MRI-transrectal ultrasound fusion biopsy information easily recognized the spatial distribution of MRI-visible and MRI-nonvisible cancer and provided better Grade Group correlation with radical prostatectomy specimens but still requires validation.

Clinical utility of histopathology data: urological cancers

Cancer datasets recommend standardised reporting of histopathological data items with elements categorised as either core (required) or non-core (recommended), irrespective of the clinical scenario. However, the clinical significance of a data item in an individual case would depend on the clinicopathological setting as well as local management guidelines. A data item that is critical for patient management in one clinical scenario may be largely irrelevant in another patient. Pathologists must understand how their data are used in clinical practice so that they can focus their limited resources appropriately. We briefly review the use of histopathological data in the management of urological cancers, highlighting scenarios where a data item may be of limited clinical utility.

Diagnostic significance of stromal changes in biopsies of prostate adenocarcinoma

The diagnostic value of stromal changes in carcinomas, including prostate, is under debate; in terms of limited sample tissue of biopsy, in addition to glandular alterations, the stromal changes could have additional diagnostic value, but the results in clinical settings are controversial. The research aims to evaluate the potential of stromal changes as a supplementary tool to predict the presence of higher grade carcinomas in the prostate using Masson's trichrome and Fanconi anemia complementation group M (FANCM) antibody stainings. 385 biopsies and corresponding radical prostatectomy specimens were analyzed to evaluate the rates of the diversity of ISUP grades. Of 128 upgraded prostatectomy cases, 82 were diagnosed with ISUP Gleason Grade 1 (GG1) in a biopsy. All 82 cancerous samples were stained with Masson's trichrome and FACNM antibody and compared with 82 samples without cancer to see if there was a difference in stromal composition. Additionally, 50 GG1 samples without the upgrade were stained to demonstrate if stromal changes can predict less differentiated carcinomas in the prostate. In FANCM stained samples, the average percentage of positively staining stroma over the total in non-upgraded GG1 biopsies was 36 % (13-59 %, SD = 11); 34 % (9-58, SD = 13) in samples from the upgraded cancerous group, and 44 % (22-69, SD = 11) in samples without cancer. In Masson's trichrome stained samples, with collagen quantified, the percentage in non-upgraded GG1 biopsies was 41 % (20-78 %, SD = 11); 44 % (23-89, SD = 15) in samples from upgraded cancerous group and 37 % (15-57, SD = 9) in samples without cancer. In both FANCM and Masson's trichrome, no statistical significance was found between upgraded and non-upgraded groups (p = 0.84 and p = 0.5, respectively), although some upgrades from GG1 to GG4 showed extreme values. The statistical significance was found in cancerous vs. benign samples with both FANCM (p < 0.01) and Masson's trichrome (p = 0.012). The main limiting factor is a significant overlap in staining intensity between cancerous and cancer-free groups.

Standardization of reporting discontinuous tumor involvement in prostatic needle biopsy: a systematic review

Discontinuous tumor involvement (DTI) is a not uncommon finding in the tumor in prostate needle core biopsies undertaken for diagnosis of prostate cancer (PCa). The objective of this review is to establish a clear definition of DTI in order to provide a standardized method of measurement which reliably reflects pathologic features and disease progression following radical prostatectomy (RP). A systematic literature search was performed using PubMed up to March 2020 to identify studies of PCa patients which included needle biopsies containing DTI and matched subsequent RP treatment with or without follow-up information. The methodology and quality of reporting of DTI are reviewed, compared, and summarized. DTI is a frequent finding in diagnostic biopsy for PCa (up to 30%). Six studies were compared by methods of measurement used for predicting pathologic features and outcomes which are observed in subsequent RP. In most cases with DTI (> 90%), intervening benign tissue in the tumor core was less than 5 mm. DTI found in the biopsy was likely to be associated with a single, irregular tumor nodule going in and out of the plane of the section, but DTI was not associated with multiple small foci of the tumor. Immunohistochemistry (IHC) also demonstrated that about 75% of cases of DTI shared an IHC profile which supports the concept that DTI most likely comes from a homogeneous tumor nodule. Furthermore, DTI was associated with positive surgical margin (PSM) and bilateral tumor in RP specimens. Compared to additive measurement (with the subtraction of intervening benign tissue), linear measurement (including intervening benign tissue) of DTI was more accurately predictive of aggressive disease in the RP including higher pT stage, PSM, and greater actual extent of the tumor. However, the advantage of linear measurement was lost in cases where there was an upgrade from the biopsy to the RP which may result from undersampling. For cases with either very small tumor foci or very extensive cancer volume, no difference was observed in these two methods of measurement. DTI in core biopsies may represent undersampling of a larger irregular nodule but likely does not result from multifocality and is similarly unlikely to represent multiclonality. Linear measurement of DTI was more accurately predictive of post-RP pathologic findings and oncologic prognosis. This method should be applied for patient selection for AS.

Clonal evaluation of prostate cancer molecular heterogeneity in biopsy samples by dual immunohistochemistry and dual RNA in situ hybridization

Prostate cancer is frequently multifocal. Although there may be morphological variation, the genetic underpinnings of each tumor are not clearly understood. To assess the inter and intra tumor molecular heterogeneity in prostate biopsy samples, we developed a combined immunohistochemistry and RNA in situ hybridization method for the simultaneous evaluation of ERG, SPINK1, ETV1, and ETV4. Screening of 601 biopsy cores from 120 consecutive patients revealed multiple alterations in a mutually exclusive manner in 37% of patients, suggesting multifocal tumors with considerable genetic differences. Furthermore, the incidence of molecular heterogeneity was higher in African Americans patients compared with Caucasian American patients. About 47% of the biopsy cores with discontinuous tumor foci showed clonal differences with distinct molecular aberrations. ERG positivity occurred in low-grade cancer, whereas ETV4 expression was observed mostly in high-grade cancer. Further studies revealed correlation between the incidence of molecular markers and clinical and pathologic findings, suggesting potential implications for diagnostic pathology practice, such as defining dominant tumor nodules and discriminating juxtaposed but molecularly different tumors of different grade patterns.

Comparison of Tumor Volume Parameters on Prostate Cancer Biopsies

CONTEXT.—

Prostate biopsy reports require an indication of prostate cancer volume. No consensus exists on the methodology of tumor volume reporting.

OBJECTIVE.—

To compare the prognostic value of different biopsy prostate cancer volume parameters.

DESIGN.—

Prostate biopsies of the European Randomized Study of Screening for Prostate Cancer were reviewed (n = 1031). Tumor volume was quantified in 6 ways: average estimated tumor percentage, measured total tumor length, average calculated tumor percentage, greatest tumor length, greatest tumor percentage, and average tumor percentage of all biopsies. Their prognostic value was determined by using either logistic regression for extraprostatic expansion (EPE) and surgical margin status after radical prostatectomy (RP), or Cox regression for biochemical recurrence-free survival (BCRFS) and disease-specific survival (DSS) after RP (n = 406) and radiation therapy (RT) (n = 508).

RESULTS.—

All tumor volume parameters were significantly mutually correlated (R2 > 0.500, P < .001). None were predictive for EPE, surgical margin, or BCRFS after RP in multivariable analysis, including age, prostate-specific antigen, number of positive biopsies, and grade group. In contrast, all tumor volume parameters were significant predictors for BCRFS (all P < .05) and DSS (all P < .05) after RT, except greatest tumor length. In multivariable analysis including only all tumor volume parameters as covariates, calculated tumor length was the only predictor for EPE after RP (P = .02) and DSS after RT (P = .02).

CONCLUSIONS.—

All tumor volume parameters had comparable prognostic value and could be used in clinical practice. If tumor volume quantification is a threshold for treatment decision, calculated tumor length seems preferential, slightly outperforming the other parameters.

Essential Updates in Grading, Morphotyping, Reporting, and Staging of Prostate Carcinoma for General Surgical Pathologists

CONTEXT.—

Within this decade, several important updates in prostate cancer have been presented through expert international consensus conferences and influential publications of tumor classification and staging.

OBJECTIVE.—

To present key updates in prostate carcinoma.

DATA SOURCES.—

The study comprised a review of literature and our experience from routine and consultation practices.

CONCLUSIONS.—

Grade groups, a compression of the Gleason system into clinically meaningful groups relevant in this era of active surveillance and multidisciplinary care management for prostate cancer, have been introduced. Refinements in the Gleason patterns notably result in the contemporarily defined Gleason score 6 cancers having a virtually indolent behavior. Grading of tertiary and minor higher-grade patterns in radical prostatectomy has been clarified. A new classification for prostatic neuroendocrine tumors has been promulgated, and intraductal, microcystic, and pleomorphic giant cell carcinomas have been officially recognized. Reporting the percentage of Gleason pattern 4 in Gleason score 7 cancers has been recommended, and data on the enhanced risk for worse prognosis of cribriform pattern are emerging. In reporting biopsies for active surveillance criteria-based protocols, we outline approaches in special situations, including variances in sampling or submission. The 8th American Joint Commission on Cancer TNM staging for prostate cancer has eliminated pT2 subcategorization and stresses the importance of nonanatomic factors in stage groupings and outcome prediction. As the clinical and pathology practices for prostate cancer continue to evolve, it is of utmost importance that surgical pathologists become fully aware of the new changes and challenges that impact their evaluation of prostatic specimens.

Updates on Grading and Staging of Prostate Cancer

Since its development between 1966 and 1977, the Gleason grading system has remained one of the most important prognostic indicators in prostatic acinar adenocarcinoma. The grading system was first majorly revised in 2005 and again in 2014. With the publication of the 8th edition of the American Joint Committee on Cancer TNM staging manual in 2018, the classification of prostate cancer and its reporting have further evolved and are now included as part of staging criteria. This article reflects the aspects that are most influential on daily practice. A brief summary of 3 ancillary commercially available genomic tests is also provided.

Continuous versus discontinuous tumor involvement: A dilemma in prostate biopsy quantitation

BACKGROUND

No consensus has been reached for an optimal method of quantifying discontinuous tumor foci separated by intervening benign tissue on prostate biopsy (PBx). We examined sets of PBx, where cancer involved only one core, and corresponding radical prostatectomy (RP) specimens.

METHODS AND RESULTS

Cases were divided into 3 groups-Group 1 (n = 80): <3 mm in end-to-end tumor measurement (continuous/discontinuous); Group 2 (n = 22): ≥3 mm in tumor length (continuous); and Group 3 (n = 15): ≥3 mm in end-to-end tumor measurement (discontinuous). The rate of Gleason score ≥7 was considerably lower in Group 1 (9%/30% on PBx/RP) than in Group 2 (50% [P < 0.001]/59% [P = 0.015] on PBx/RP) or Group 3 (40% [P = 0.005]/46% [P = 0.237] on PBx/RP). pT2 disease was significantly more often found in Group 1 (88%) than in Group 2 (68%, P = 0.049) or Group 3 (60%, P = 0.018). Surgical margin was significantly more often positive in Group 3 (27%) than in Group 1 (5%, P = 0.020), but not Group 2 (9%, P = 0.198). Moreover, estimated cancer volume (cc, mean ± SD) was significantly smaller in Group 1 (1.89 ± 1.98) than in Group 2 (3.56 ± 2.92, P = 0.026) or Group 3 (3.44 ± 2.02, P = 0.013). Kaplan-Meier analysis revealed higher risks of biochemical recurrence after RP in Group 2, compared with Group 1 (P = 0.001) or Group 3 (P = 0.096). In 93 patients with biopsy Gleason score 6 cancer, higher rates of pT2+/3 disease (P = 0.023) and positive margin (P = 0.026), as well as larger cancer volume (P = 0.063), on RP were still seen in Group 3, compared with Group 1, but their differences were not statistically significant between Group 2 and Group 3.

CONCLUSIONS

Linear quantitation including intervening benign tissue on PBx may more precisely predict the actual tumor extent.

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.

Clonal evaluation of prostate cancer foci in biopsies with discontinuous tumor involvement by dual ERG/SPINK1 immunohistochemistry

The presence of two or more prostate cancer foci separated by intervening benign tissue in a single core is a well-recognized finding on prostate biopsy. Cancer involvement can be measured by including intervening benign tissue or only including the actual cancer involved area. Importantly, this parameter is a common enrollment criterion for active surveillance protocols. We hypothesized that spatially distinct prostate cancer foci in biopsies may arise from separate clones, impacting cancer involvement assessment. Hence, we used dual ERG/SPINK1 immunohistochemistry to determine the frequency of separate clones-when separate tumor foci showed discordant ERG and/or SPINK1 status-in discontinuously involved prostate biopsy cores from two academic institutions. In our cohort of 97 prostate biopsy cores with spatially discrete tumor foci (from 80 patients), discontinuous cancer involvement including intervening tissue ranged from 20 to 100% and Gleason scores ranged from 6 to 9. Twenty-four (25%) of 97 discontinuously involved cores harbored clonally distinct cancer foci by discordant ERG and/or SPINK1 expression status: 58% (14/24) had one ERG(+) focus, and one ERG(-)/SPINK1(-) focus; 29% (7/24) had one SPINK1(+) focus and one ERG(-)/SPINK1(-) focus; and 13% (3/24) had one ERG(+) focus and one SPINK1(+) focus. ERG and SPINK1 overexpression were mutually exclusive in all tumor foci. In summary, our results show that ~25% of discontinuously involved prostate biopsy cores showed tumor foci with discordant ERG/SPINK1 status, consistent with multiclonal disease. The relatively frequent presence of multiclonality in discontinuously involved prostate biopsy cores warrants studies on the potential clinical impact of clonality assessment, particularly in cases where tumor volume in a discontinuous core may impact active surveillance eligibility.