Use of prostate-specific antigen and tumor volume in predicting needle biopsy grading error

Pilot study for supervised target detection applied to spatially registered multiparametric MRI in order to non-invasively score prostate cancer

BACKGROUND

Gleason Score (GS) is a validated predictor of prostate cancer (PCa) disease progression and outcomes. GS from invasive needle biopsies suffers from significant inter-observer variability and possible sampling error, leading to underestimating disease severity ("underscoring") and can result in possible complications. A robust non-invasive image-based approach is, therefore, needed.

PURPOSE

Use spatially registered multi-parametric MRI (MP-MRI), signatures, and supervised target detection algorithms (STDA) to non-invasively GS PCa at the voxel level.

METHODS AND MATERIALS

This study retrospectively analyzed 26 MP-MRI from The Cancer Imaging Archive. The MP-MRI (T2, Diffusion Weighted, Dynamic Contrast Enhanced) were spatially registered to each other, combined into stacks, and stitched together to form hypercubes. Multi-parametric (or multi-spectral) signatures derived from a training set of registered MP-MRI were transformed using statistics-based Whitening-Dewhitening (WD). Transformed signatures were inserted into STDA (having conical decision surfaces) applied to registered MP-MRI determined the tumor GS. The MRI-derived GS was quantitatively compared to the pathologist's assessment of the histology of sectioned whole mount prostates from patients who underwent radical prostatectomy. In addition, a meta-analysis of 17 studies of needle biopsy determined GS with confusion matrices and was compared to the MRI-determined GS.

RESULTS

STDA and histology determined GS are highly correlated (R = 0.86, p < 0.02). STDA more accurately determined GS and reduced GS underscoring of PCa relative to needle biopsy as summarized by meta-analysis (p < 0.05).

CONCLUSION

This pilot study found registered MP-MRI, STDA, and WD transforms of signatures shows promise in non-invasively GS PCa and reducing underscoring with high spatial resolution.

Pathological upgrading in prostate cancer patients eligible for active surveillance: Does prostate-specific antigen density matter?

Purpose

To evaluate prospectively the role of prostate-specific antigen (PSA) density in predicting Gleason score upgrading in prostate cancer patients eligible for active surveillance (T1/T2, biopsy Gleason score≤6, PSA≤10 ng/mL, and ≤2 positive biopsy cores).

Materials and Methods

Between January 2010 and November 2013, among patients who underwent greater than 10-core transrectal ultrasound-guided biopsy, 60 patients eligible for active surveillance underwent radical prostatectomy. By use of the modified Gleason criteria, the tumor grade of the surgical specimens was examined and compared with the biopsy results.

Results

Tumor upgrading occurred in 24 patients (40.0%). Extracapsular disease and positive surgical margins were found in 6 patients (10.0%) and 8 patients (17.30%), respectively. A statistically significant correlation between PSA density and postoperative upgrading was found (p=0.030); this was in contrast with the other studied parameters, which failed to reach significance, including PSA, prostate volume, number of biopsy cores, and number of positive cores. Tumor upgrading was also highly associated with extracapsular cancer extension (p=0.000). The estimated optimal cutoff value of PSA density was 0.13 ng/mL², obtained by receiver operating characteristic analysis (area under the curve=0.66; p=0.020; 95% confidence interval, 0.53-0.78).

Conclusions

PSA density is a strong predictor of Gleason score upgrading after radical prostatectomy in patients eligible for active surveillance. Because tumor upgrading increases the potential for postoperative pathological adverse findings and prognosis, PSA density should be considered when treating and consulting patients eligible for active surveillance.

The role of PSA density to predict a pathological tumour upgrade between needle biopsy and radical prostatectomy for low risk clinical prostate cancer in the modified Gleason system era

OBJECTIVES

We evaluate the role of prostate-specific antigen (PSA) density to predict Gleason score upgrade between prostate biopsy material and radical prostatectomy specimen examination in patients with low-risk prostate cancer.

METHODS

Between January 2007 and November 2011, 133 low-risk patients underwent a radical prostatectomy. Using the modified Gleason criteria, tumour grade of the surgical specimens was examined and compared to the biopsy results.

RESULTS

A tumour upgrade was noticed in 57 (42.9%) patients. Organ-confined disease was found in 110 (82.7%) patients, while extracapsular disease and seminal vesicles invasion was found in 19 (14.3%) and 4 (3.0%) patients, respectively. Positive surgical margins were reported in 23 (17.3%) patients. A statistical significant correlation between the preoperative PSA density value and postoperative upgrade was found (p = 0.001) and this observation had a predictive value (p = 0.002); this is in contrast to the other studied parameters which failed to reach significance, including PSA, percentage of cancer in biopsy and number of biopsy cores. Tumour upgrade was also highly associated with extracapsular cancer extension (p = 0.017) and the presence of positive surgical margins (p = 0.017).

CONCLUSIONS

PSA density represents a strong predictor for Gleason score upgrade after radical prostatectomy in patients with clinical low-risk disease. Since tumour upgrade increases the potential for postoperative pathological adverse findings and prognosis, PSA density should be considered when treating and consulting patients with low-risk prostate cancer.

Clinical and pathological variables that predict changes in tumour grade after radical prostatectomy in patients with prostate cancer

INTRODUCTION

Preoperative Gleason score is crucial, in combination with other preoperative parameters, in selecting the appropriate treatment for patients with clinically localized prostate cancer. The aim of the present study is to determine the clinical and pathological variables that can predict differences in Gleason score between biopsy and radical prostatectomy.

METHODS

We retrospectively analyzed the medical records of 302 patients who had a radical prostatectomy between January 2005 and September 2010. The association between grade changes and preoperative Gleason score, age, prostate volume, prostate-specific antigen (PSA), PSA density, number of biopsy cores, presence of prostatitis and high-grade prostatic intraepithelial neoplasia was analyzed. We also conducted a secondary analysis of the factors that influence upgrading in patients with preoperative Gleason score ≤6 (group 1) and downgrading in patients with Gleason score ≤7 (group 2).

RESULTS

No difference in Gleason score was noted in 44.3% of patients, while a downgrade was noted in 13.7% and upgrade in 42.1%. About 2/3 of patients with a Gleason score of ≤6 upgraded after radical prostatectomy. PSA density (p = 0.008) and prostate volume (p = 0.032) were significantly correlated with upgrade. No significant predictors were found for patients with Gleason score ≤7 who downgraded postoperatively.

CONCLUSION

Smaller prostate volume and higher values of PSA density are predictors for upgrade in patients with biopsy Gleason score ≤6 and this should be considered when deferred treatment modalities are planned.

Upgrading and downgrading of prostate cancer from biopsy to radical prostatectomy: incidence and predictive factors using the modified Gleason grading system and factoring in tertiary grades

BACKGROUND

Prior studies assessing the correlation of Gleason score (GS) at needle biopsy and corresponding radical prostatectomy (RP) predated the use of the modified Gleason scoring system and did not factor in tertiary grade patterns.

OBJECTIVE

To assess the relation of biopsy and RP grade in the largest study to date.

DESIGN, SETTING, AND PARTICIPANTS

A total of 7643 totally embedded RP and corresponding needle biopsies (2004-2010) were analyzed according to the updated Gleason system.

INTERVENTIONS

All patients underwent prostate biopsy prior to RP.

MEASUREMENTS

The relation of upgrading or downgrading to patient and cancer characteristics was compared using the chi-square test, Student t test, and multivariable logistic regression.

RESULTS AND LIMITATIONS

A total of 36.3% of cases were upgraded from a needle biopsy GS 5-6 to a higher grade at RP (11.2% with GS 6 plus tertiary). Half of the cases had matching GS 3+4=7 at biopsy and RP with an approximately equal number of cases downgraded and upgraded at RP. With biopsy GS 4+3=7, RP GS was almost equally 3+4=7 and 4+3=7. Biopsy GS 8 led to an almost equal distribution between RP GS 4+3=7, 8, and 9-10. A total of 58% of the cases had matching GS 9-10 at biopsy and RP. In multivariable analysis, increasing age (p<0.0001), increasing serum prostate-specific antigen level (p<0.0001), decreasing RP weight (p<0.0001), and increasing maximum percentage cancer/core (p<0.0001) predicted the upgrade from biopsy GS 5-6 to higher at RP. Despite factoring in multiple variables including the number of positive cores and the maximum percentage of cancer per core, the concordance indexes were not sufficiently high to justify the use of nomograms for predicting upgrading and downgrading for the individual patient.

CONCLUSIONS

Almost 20% of RP cases have tertiary patterns. A needle biopsy can sample a tertiary higher Gleason pattern in the RP, which is then not recorded in the standard GS reporting, resulting in an apparent overgrading on the needle biopsy.

Factors predicting Gleason score 6 upgrading after radical prostatectomy

Objectives

Prostate cancer Gleason score 6 is the most common score detected on prostatic biopsy. We analyzed the clinical parameters that predict the likelihood of Gleason score upgrading after radical prostatectomy.

Methods

The study population consisted of 241 patients who underwent radical retropubic prostatectomy between Feb 2002 and Dec 2007 for Gleason score 6 adenocarcinoma. The influence of preoperative parameters on the probability of a Gleason score upgrading after surgery was evaluated using multivariate logistic regression and ROC curves.

Results

Gleason score upgrade was found in 92 of 241 patients (38.2%). Multivariate logistic regression analysis showed that only percentage of cancer in dominant lobe and prostate weight were significant predictors for Gleason score upgrading (p = 0.043 and p = 0.006, respectively). ROC curves showed that prostate weight and PSA density were only two independent significant parameters for prediction of upgrade (AUC – 0.634, p <0.0001 and 0.604, p = 0.006, respectively). Gleason score upgrading was observed to be accompanied by significantly higher rates of extra prostatic extension (p <0.001) and seminal vesicle invasion (p = 0.002).

Conclusions

Almost forty percent of tumors graded Gleason 6 at biopsy are Gleason 7 at surgery. Upgraded tumors significantly associated with adverse pathological features. The probability of Gleason score upgrade can be predicted using prostate weight and PSA density as independent parameters.

Pathological correlation between needle biopsy and radical prostatectomy specimen in patients with localized prostate cancer

OBJECTIVE

This study aims to evaluate the accuracy of transrectal ultrasound (TRUS) guided prostate biopsies in predicting pathological grading and tumour distribution in the final pathological specimen of patients who underwent radical prostatectomy for clinically localized prostate cancer. The study ultimately aims to gain more understanding of the pathological behaviour of prostate cancer and the limitations of the currently available diagnostic and prognostic tools.

MATERIAL AND METHODS

We reviewed the records of 100 patients with localized carcinoma of the prostate diagnosed by TRUS-guided prostate biopsy and treated with radical retropubic prostatectomy, comparing tumour laterality and Gleason score in core biopsies with tumour distribution and Gleason score of the surgical specimen. We then correlated both results to diagnostic and prognostic variables such as prostate specific antigen (PSA) values and surgical margins.

RESULTS

All 44 patients with bilateral disease on needle biopsy had bilateral disease on final pathology, with 15 of these patients (34%) having positive margins. Of the 56 patients with unilateral disease on biopsy, 37 (66%) had bilateral disease on final pathology; however, only 4 of them (7%) had positive margins (p < 0.001). Median Gleason score on final pathology was upgraded to 7, compared with a median score of 6 on biopsies. Stratifying patients to 2 groups based on their PSA level (group 1: PSA < 10 ng/mL, 72 patients; group 2: PSA > 10ng/mL, 28 patients), revealed that 57 patients (79%) in group 1 and 24 patients (85%) in group 2 had bilateral disease. In addition, 13 patients (18%) in group 1 and 6 patients (21%) in group 2 had positive margins.

CONCLUSIONS

Sixty-six percent of patients with unilateral disease on needle biopsy had bilateral disease on final pathology, but this does not increase their rate of having positive margins. Gleason score is upgraded from 6 to 7. PSA did not seem to affect laterality of disease in patients selected for radical prostatectomy.

Predictors for clinically relevant Gleason score upgrade in patients undergoing radical prostatectomy

OBJECTIVE

To evaluate clinical predictors for Gleason score upgrade (GSU) in radical prostatectomy (RP) specimen, especially in patients with 'very' low risk PCA (T1c and biopsy Gleason score ≤6 and PSA <10 ng/ml and ≤2 positive biopsy cores and PSA density <0.15).

PATIENTS AND METHODS

402 consecutive patients undergoing RP between 2004 and 2006, including a subgroup of 62 patients with 'very' low risk PCA, were examined. Patients were categorized for clinically relevant GSU (defined as upgrade into a higher PCA risk category). Parameters including number of biopsy cores obtained, positive biopsy cores, prostate weight, PSA, DRE and pathology department were evaluated for their role as predictors. Furthermore, GSU in RP specimen was analyzed for its impact on pT-stage.

RESULTS

Clinically relevant GSU occurred in 38.1% in the whole cohort and in 32.3% in the 'very' low risk PCA subgroup. Gleason score downgrade (GSD) occurred in 4.7%. Number of biopsy cores obtained and prostate weight were independent negative predictors of GSU in all 402 patients (P = 0.02 and P = 0.03, respectively). In the 'very' low risk group, only number of biopsy cores obtained revealed as an independent negative predictor of GSU (P = 0.02). PSA, DRE, number of positive cores or pathology department were not associated to GSU. In the 'very' low risk group, GSU was related with extracapsular tumor extension (P = 0.05).

CONCLUSIONS

Clinically relevant GSU in RP specimen is still a challenging problem. Increasing the number of biopsy cores lower this risk significantly. GSD is rare and thus of minor importance for treatment decisions.

DNA Ploidy as surrogate for biopsy gleason score for preoperative organ versus nonorgan-confined prostate cancer prediction

OBJECTIVES

Transformation of normal epithelium into cancer cells involves epigenetic and genetic changes and modifications in nuclear structure and tissue architecture. To evaluate nuclear morphometric alterations and clinicopathologic features for organ- vs nonorgan-confined prostate carcinoma (PCa) prediction.

METHODS

Of 557 prospectively enrolled patients, 370 had complete information and sufficient tumor area for all evaluated parameters (281 organ-confined and 89 nonorgan-confined PCa cases). Digital images of Feulgen DNA-stained nuclei were captured from biopsies using the AutoCyte imaging system, and the nuclear morphometric alterations were calculated. Logistic regression analysis with bootstrap resampling was used to determine the factors important for differentiation of the 2 groups and to generate models for organ- vs nonorgan-confined PCa prediction.

RESULTS

Several nuclear morphometric features were significantly altered and could differentiate organ- and nonorgan-confined disease. DNA ploidy was the most important factor among the significant nuclear morphometric features and was the second most important factor for organ- vs nonorgan-confined PCa prediction when considered with total prostate-specific antigen (PSA), complexed PSA, free/total PSA, biopsy Gleason score, and clinical stage. The combination of DNA ploidy with clinical stage, total PSA, and biopsy Gleason score showed an improvement of 1.5% in the area under the receiver operator characteristic curves compared with the combination of clinical stage, total PSA, and biopsy Gleason (73.97% vs 72.43%). The use of DNA ploidy in lieu of the biopsy Gleason score in each preoperative model evaluated resulted in equivalent or improved organ- vs nonorgan-confined PCa prediction.

CONCLUSIONS

The results of our study have shown that DNA ploidy can serve as a surrogate biomarker that has the potential to replace biopsy Gleason scores for organ- vs nonorgan-confined PCa prediction.

Prostate cancer volume at biopsy predicts clinically significant upgrading

PURPOSE

A significant proportion of patients with prostate cancer with Gleason score 6 disease at biopsy is upgraded to Gleason score 7 or higher after radical prostatectomy, increasing the risk of adverse outcome. We identified clinical and pathological parameters that predict pathological upgrading in this population.

MATERIALS AND METHODS

A total of 268 patients with biopsy Gleason score 6 prostate cancer who underwent biopsy and radical prostatectomy between October 1999 and January 2007 were included in the study. Pretreatment characteristics were used to identify predictors of pathological upgrading. Upgrading significance was established by comparing radical prostatectomy pathology between cases that were and were not upgraded.

RESULTS

A total of 134 patients (50%) were upgraded postoperatively to Gleason score 7 or higher. Preoperative prostate specific antigen greater than 5.0 ng/ml (p = 0.036), prostate weight 60 gm or less (p = 0.004) and more cancer volume at biopsy, defined by cancer involving greater than 5% of the biopsy tissue (p = 0.002), greater than 1 biopsy core (p <0.001) or greater than 10% of any core (p = 0.014), were associated with pathological upgrading. Upgraded patients were more likely to have extraprostatic extension and positive surgical margins at radical prostatectomy (p <0.001 and 0.001, respectively).

CONCLUSIONS

Prostate specific antigen, prostate volume and biopsy cancer volume predict clinically significant upgrading in patients diagnosed with Gleason score 6 disease. These parameters may be valuable in the pretreatment risk assessment of this patient population.

Does prostate biopsy Gleason score accurately express the biologic features of prostate cancer?

PURPOSE

To correlate Gleason grading in prostate biopsies with the final Gleason score in radical prostatectomy specimens, and to investigate predictors for concordance and preoperative undergrading.

MATERIALS AND METHODS

The charts of 303 patients who underwent radical retropubic prostatectomy between 1992 and 2002 were retrospectively reviewed. Prostate biopsy and surgical specimen Gleason scores and correlative clinical data were recorded, and a multivariate analysis model was applied.

RESULTS

Data were available in 293 cases (97%). The preoperative biopsy predicted the prostatectomy Gleason score accurately in 51% and undergraded them in 41% of the patients. Accuracy rates were significantly higher for Gleason scores 7-10 compared to low Gleason scores (2-4), concordance 90% and 6%, respectively (P < 0.01). Moreover, accuracy rates were higher in patients with prostate-specific antigen (PSA) higher than 10 ng/ml (85% vs. 40%; P < 0.01) and prostate glands smaller than 55 g (68% vs. 38%; P < 0.01). In 233 patients, the biopsy Gleason score did not include 4 or 5 components. Upgrading to 4 or 5 in 1 of the components was noted in 32 patients (14%). Multivariate analysis revealed that upgrading is associated with preoperative serum PSA (odds ratio 1.05; P < 0.05) and the percentage of positive cores in the biopsy (odds ratio 1.47; P < 0.001).

CONCLUSIONS

Biopsy Gleason scores of 2-4, low PSA, and a low percentage of positive cores in the biopsy can predict the biopsy driven biologically significant undergrading of 1 of the components of the Gleason score that may adversely affect therapeutic decisions.

Increasing the number of biopsies increases the concordance of Gleason scores of needle biopsies and prostatectomy specimens

PURPOSE

To determine the importance of increasing the number of biopsy cores to decrease the discrepancy of Gleason scores of needle biopsy and radical prostatectomy specimens.

MATERIALS AND METHODS

Between May 1998 and July 2005, 392 patients with clinically localized prostate cancer diagnosed by 18-gauge transrectal needle biopsy underwent radical prostatectomy. We categorized the cohort into 2 groups according to the number of the cores. Group 1 consisted of 206 patients diagnosed by extended biopsies (> or =10 cores, range 10-14, median 11). The remaining 186 patients who were diagnosed by sextant biopsies were categorized as being in group 2. Preoperative clinical variables, including patient age, digital rectal examination findings, serum prostate-specific antigen, and the number of cores positive for cancer the parameters, were assessed in both groups. The concordance of Gleason scores in both groups were analyzed by both individual Gleason scores and clinical subgroups of Gleason scores: 2-4 (well differentiated), 5-6 (moderately differentiated), 7 (intermediate), and 8-10 (poorly differentiated).

RESULTS

Needle biopsies revealed moderately differentiated tumors (Gleason 5-6) for the 2 groups (55.3% and 60.2%). Gleason scores of the needle biopsies were identical to that of the prostatectomy specimen in 116 (56.31%) and 76 cases (40.86%) for each group (kappa: 0.432 and 0.216 for each group, respectively). Gleason score of the needle biopsy differed by 1 grade in 56 (27.18%) and 84 cases (45.16%), and by > or =2 units in 34 (16.50%) and 26 cases (15.05%) for each group, respectively. Of the specimens, 34% were undergraded, and 10% were overgraded in group 1. These rates were 38% and 22% in group 2, respectively. A total of 70% in group 1 and 56% in group 2 remained in the same categorical group, 28% and 32% of the specimens were undergraded, and 4% and 12% were overgraded in groups 1 and 2, respectively. In group 1, the number of patients with Gleason scores of 2-4, 5-6, 7, and 8 were 9.7%, 55.3%, 21.4%, 13.6%, and 1.9%, 47.6%, 32%, 18.4%, graded by needle biopsies and radical prostatectomy specimens, respectively. However, in the sextant group, the change was the number of patients with Gleason scores of 2-4, 5-6, 7, and 8-10 was 5.4% 60.2%, 24.7%, and 9.7%, detected by needle biopsies, respectively. Radical prostatectomy specimens revealed the same Gleason categories in 4.3%, 41.9%, 38.7%, and 15.1%, respectively. There was no correlation between categorized prostate-specific antigen levels and concordance of the Gleason grade. Age and digital rectal examination results did not affect Gleason correlation.

CONCLUSIONS

We have shown that an extended biopsy scheme beyond its superior diagnostic capability also improves the concordance of Gleason scores of needle biopsies and radical prostatectomy specimens.

Contemporary pathology of prostate cancer

In less than 20 years since the introduction of serum PSA and the spring-loaded 18-gauge prostatic biopsy needle, pathologists have adjusted to the limited tissue requirements of narrow needle specimens to apply criteria for diagnosis and grading of prostate cancer, borrowing from lessons learned from radical prostatectomies. Substantial gains have been made during this period in the understanding of precancerous lesions, mimics of malignancy, the criteria for minimal cancer, variants of cancer, and treatment-induced changes. The light microscopic findings remain the criterion standard for diagnosis against which all new techniques should be measured. Numerous findings have proven to be of value, including simple quantitation of histopathologic features, cancer volume, perineural invasion, and others.

The value of multiple core biopsies for predicting the Gleason score of prostate cancer

OBJECTIVE

To evaluate the accuracy of Gleason grading of prostate cancer in multiple core biopsies, compared with the final Gleason score of total prostatectomy specimens, and to investigate whether the prediction of the correct Gleason score is improved by increasing the number of biopsies.

PATIENTS AND METHODS

Before total prostatectomy, 121 men had a mean (range) of 10.0 (8-14) transrectal ultrasonography (TRUS)-guided core biopsies taken from the apex, mid-medial, mid-lateral and basal regions, from the transition zone and from lesions detected on TRUS. The biopsies and prostatectomy specimens were reviewed and the Gleason scores assessed.

RESULTS

The preoperative biopsies predicted the prostatectomy Gleason score exactly in 45.5% of the patients and within one Gleason score in 93.4%. The biopsies under-graded the prostate cancer in 38.8% and overgraded it in 15.7%. The weighted kappa value for exact agreement was 0.502. If one biopsy was positive for cancer, the prostatectomy Gleason score was predicted correctly in 43.8% and within one score in 93.8%, compared with 53.8% and 92.3%, respectively, if cancer was found in at least seven biopsies. If the mid-lateral and transition zone biopsies had been excluded from the biopsy protocol, 5% of the cancers would have been undetected. Among the remaining 115 cancers, grading accuracy only improved from 43.5% to 45.2% by adding biopsies to the sextant protocol.

CONCLUSION

Despite a statistically significant agreement between biopsy and prostatectomy Gleason score, under-grading remains a major problem. The prediction of the prostatectomy Gleason score is only marginally improved by increasing the number of biopsies.

Discrepancies between Gleason scores of needle biopsy and radical prostatectomy specimens

The purpose of this study was to determine the accuracy of Gleason scores in prostate needle biopsy diagnosis and to investigate factors affecting the accuracy of the tumor grade. A single pathologist reviewed 116 sets of prostate cancer biopsies and radical prostatectomy specimens. The following factors were examined to determine their effect on the accuracy of the biopsy Gleason scores: (i) relative tumor differentiation; (ii) pathological stage; (iii) amount of tissue in the biopsy specimen; (iv) amount of cancer tissue in the biopsy specimen; (v) tumor heterogeneity; (vi) clinical findings (prostate specific antigen value and digital rectal examination); and (vii) interobserver variability. In 53 cases the Gleason score of biopsy specimens was identical to the score of prostatectomy specimens (45.7%). Fifty-four cases (46.6%) of biopsy specimens were undergraded. The most common discrepancy was diagnosis of well-differentiated carcinoma in the biopsy but diagnosis of moderately differentiated tumor in the corresponding prostatectomy specimen. This discrepancy occurred when the amount of tumor in the biopsy was 3 mm or less. Biopsy and prostatectomy results showed less agreement when the original biopsy tumor grade rendered by nine different pathologists was used, suggesting that interobserver variability can adversely affect the accuracy of tumor grade. Clarifying the histologic criteria for distinguishing each grade, especially between Gleason grades 2 and 3, is important for accurate grading.

Prostate biopsy grading errors: a sampling problem?

Potential reasons for discordance between the Gleason score in biopsies and surgical specimens are: 1) pathological interpretation bias, and 2) sampling effects. The importance of sampling effects in grading errors was examined in a series where the number of biopsy cores obtained was high. Biopsies were obtained using a technique whereby 18 directed cores were systematically obtained and mapped out within the gland. Gleason scores from biopsies and matched prostatectomy specimens were compared among 28 consecutive patients with localized prostate cancer. A pooled database from 10 series (n = 2,687) served as a baseline for comparison in the accuracy of Gleason score grading. With the present biopsy technique, an exact Gleason score match was achieved in 57% of cases, compared with the pooled database (PD) mean of 42% (P = 0.055), and was within 1 point in 93% of cases compared with 78% (PD) (P = 0.029). Upgrading of biopsies was seen in 35% of cases, compared with 43% (PD) (P = 0.19). With respect to Gleason score 7, an exact match was present in 78% of cases, compared with 63% (PD) (P = 0.17), and upgrading was 0%, compared with 20% (PD) (P = 0.07). The data suggest a significant reduction in grade errors by minimizing sampling effects, one that it is of the same order of magnitude as the reduction achieved from consensus pathologic evaluation. In our study, seven patients (25%) would have had their cancers missed altogether with sextant biopsies. Sampling effects may contribute significantly to grading errors in prostate needle biopsies, although a larger study is needed to confirm this. A methodology which adopts a higher number of cores combined with a consensus pathologic evaluation could potentially reduce grading errors substantially. The optimal number of cores remains to be determined in a larger study. Int. J. Cancer (Radiat. Oncol. Invest.) 90, 326-330 (2000).

Patterns of prostate cancer biopsy grading: trends and clinical implications

The predictive value of Gleason grading from prostate needle biopsy was examined and the patterns of grade discordance with surgical specimens are discussed in terms of their clinical implications. Gleason scores from biopsy and matched radical prostatectomy specimens were compared in 428 consecutive patients. Patterns of concordance were examined with respect to numerical agreement as well as to whether differences result in a change in group assignment with respect to Gleason score group 2-4, 5-6, 7, and 8-10. The coefficient of agreement, kappa, and accuracy were used to measure predictive value. An exact Gleason score match was present in 41% of the cases, while 48% were undergraded and 17% overgraded. With respect to group assignment, 51% remained unchanged while 35% were undergraded and 14% overgraded. Kappa analysis yielded a value of 0.26, which represents a poor agreement beyond chance. A Gleason score of 5-6, 7, or 8 was reproduced in 52%, 53%, and 58% of cases, respectively. A systematic bias toward progressive undergrading of more well-differentiated cancers and overgrading of more poorly differentiated cancers on biopsy is suggested by the data. A pooled analysis with nine additional series (n = 2,687) confirms this conclusion. No correlation was found between the amount of tumor in the biopsy specimen and grade discordance. Biases in pathologic interpretation and sampling effects are suggested as responsible for grade discordance. Predictable differences exist between the histologic grade in prostate needle biopsies and the surgical specimen. Clinical staging of organ-confined prostate cancer should include the likelihood of histologic upgrading or downgrading when used to stratify patients for clinical trials, in comparing results among therapies based on biopsy grading and when recommending a radical therapy. Developing a methodology which reduces both sampling effects and pathologic interpretation bias would likely result in significantly improved accuracy of Gleason grading of prostate biopsies. Int. J. Cancer (Radiat. Oncol. Invest.) 90, 305-311 (2000).

Should a Gleason score be assigned to a minute focus of carcinoma on prostate biopsy?

The grading system for prostate carcinoma devised by Gleason is a strong prognostic indicator. The primary and secondary patterns are combined to give a tumor score, referred to as Gleason score or sum. Gleason scores on biopsy correlate with the prostatectomy Gleason scores, and in combination with pretreatment serum prostate-specific antigen and digital rectal examination results, predict tumor stage and lymph node status. However, when only a minute focus of tumor is present on biopsy, the Gleason score is assigned by doubling the Gleason pattern. The goal of this study was to determine if a Gleason score assigned to a minimal focus of adenocarcinoma had predictive value. Paired biopsies and prostatectomy specimens from 963 cases of men with clinically localized prostate cancer were examined. Minimal tumor on biopsy was defined as less than 1 mm or 5% involvement of one biopsy core; excluded from this definition were biopsies where two Gleason patterns could be identified and/or tumor was seen on more than one biopsy core. Terms often used to describe these lesions include "single minute focus of carcinoma" or "adenocarcinoma, too small to give a Gleason grade." One hundred five cases (10.9%) met the above criteria for minimal carcinoma. The correlation of Gleason scores between biopsies and prostatectomy specimens overall was good with exact agreement for 57% of cases and a difference of +/-1 unit in 92% of cases. The correlation for the minimal tumors on biopsy and prostatectomy was slightly worse with exact agreement in 52.4% (55 of 105) and a difference of +/-1 unit in 87.6% (92 of 105). The majority of minimal tumors (83.8% or 88 of 105) were assigned a Gleason score of 6. A total of 31.8% of these 88 cases were upgraded and 5.7% were downgraded. Multivariate analysis on all cases looking for predictors of tumor stage found biopsy Gleason score, perineural invasion, pretreatment prostatic-specific antigen, and digital rectal examination all predicted higher tumor stage with odds ratios of 1.86 (95% confidence interval [CI], 1.53-2.27; p = 0.0001), 2.06 (95% CI, 1.43-2.95; p = 0.0001), 1.08 (95% CI, 1.05-1.11; p = 0.0001), and 1.41 (95% CI, 1.04-1.91; p = 0.0289), respectively. In a model restricted to the 105 cases with minimal carcinoma, pretreatment prostatic-specific antigen was the only independent predictor of higher tumor stage with an odds ratio of 1.15 (95% CI, 1.01-1.31; p = 0.0380); Gleason score was not found to significantly predict higher tumor stage (odds ratio, 1.156; p = 0.6680). The results of this study confirm that biopsy Gleason score in most cases predicts prostatectomy Gleason score and tumor stage. However, for cases with minimal tumor on biopsy, the assigned Gleason score did not predict tumor stage. To properly convey this uncertainty to clinicians, a cautionary note should accompany Gleason scores derived from a minimal focus of carcinoma.

Prostate biopsy interpretation. Current concepts, 1999

Needle biopsy of the prostate has a pivotal role in the diagnosis of prostate cancer and the prediction of outcome. Strategies for sampling the prostate are being refined, which will increase the diagnostic yield. In combination with other clinical factors, the pathologic findings obtained from the biopsy specimen provide enhanced predictive accuracy for stage and individual outcome.

Needle biopsy DNA ploidy status predicts grade shifting in prostate cancer

DNA ploidy analysis of prostate needle biopsy specimens was performed to determine whether ploidy status could predict tumor grade shifting at radical prostatectomy. The paired needle biopsy and radical prostatectomy specimens from 111 randomly selected men with prostate cancer were obtained from the surgical pathology files of the Albany Medical Center Hospital. The original tumor grades were assigned by a staff of 12 surgical pathologists according to the Gleason system. Tumors with original Gleason scores < or = 6 were classified as low grade, and tumors with scores of > or = 7 were considered high grade. DNA ploidy analysis was performed on the needle biopsy specimens using the CAS 200 image analyzer (Becton Dickinson Immunocytometry Systems, Mountain View, CA, USA) on Feulgen stained 5-microm tissue sections. There were 88 diploid and 23 nondiploid cases. Thirty-eight of 111 (34%) of cases had grade shifting from needle biopsy to radical prostatectomy specimens. Of 89 low-grade needle biopsy cases, 28 (31%) were upgraded at radical prostatectomy. Of 22 high-grade needle biopsy cases, 10 (45%) were downgraded to low grade at radical prostatectomy. Of the 28 low-grade needle biopsy specimens that were upgraded at radical prostatectomy, 19 (68%) featured an aneuploid histogram and 9 (32%) were diploid. Nineteen of 28 (68%) of aneuploid low-grade tumors on needle biopsy became high-grade at radical prostatectomy. Nine of 10 (90%) diploid high-grade tumors at needle biopsy became low-grade at radical prostatectomy. Of the 38 cases in which ploidy and grade were incongruous, 28 (74%) had grade shifting. In a multivariate regression analysis, a high-grade Gleason score on radical prostatectomy specimens correlated significantly with needle biopsy ploidy (p = 0.0001) but not with needle biopsy grade (p = 0.15). The sensitivity of the needle biopsy grade in the detection of high-grade tumors on radical prostatectomy was 30%, and the specificity was 86%. The sensitivity of ploidy status in the prediction of high grade at radical prostatectomy was 78%, and the specificity was 96%. With a prostate-specific antigen (PSA) level of >0.4 ng/ml as the indicator of post-radical prostatectomy disease recurrence on a subset of 106 patients, on univariate analysis, disease recurrence was predicted by needle biopsy ploidy (p = 0.001) and radical prostatectomy grade (p = 0.04) but not by needle biopsy grade (p = 0.39). On multivariate analysis, needle biopsy DNA ploidy status independently predicted disease recurrence (p = 0.002), whereas needle biopsy and prostatectomy grade did not. These results indicate that DNA ploidy analysis of needle biopsy specimens of prostate cancer predicts grade shifting, that it is a more sensitive and specific indicator of final tumor grade at radical prostatectomy than is the original needle biopsy grade, and that ploidy status independently predicts postoperative disease recurrence.

Correlação entre a graduação histológica de biópsias e do espécimen cirúrgico em câncer da prostata

Foram estudados, retrospectivamente, os prontuários de 120 pacientes com câncer localizado da próstata nos estádios clínicos T1, T2 e T3a e que foram submetidos a 1infadenectomia ilíaca e a cirurgia radical da próstata. Todos haviam sido graduados pela escala de Gleason através de biópsias da próstata guiadas pela ultra-sonografia transretal. Correlacionamos a graduação histo1ógica destas biópsias da próstata com a graduação final obtida no exame da peça cirúrgica correspondente e obtivemos exata concordância em 39 pacientes (32,50%). Ao considerarmos a concordância de ± 1unidade, observamos concordância de resultado em 81 pacientes (67,50%). A subgraduação histológica das biópsias prostáticas foi encontrada em 75 pacientes (62,50%) dos casos.

Histopathologic review of prostate biopsies from patients referred to a comprehensive cancer center: correlation of pathologic findings, analysis of cost, and impact on treatment

BACKGROUND

Clinicians at the Fox Chase Cancer Center (FCCC) base prostate carcinoma treatment decisions regarding need to treat, field size, total dose, and adjuvant hormonal therapy on known prognostic factors including clinical stage, Gleason score (GS), perineural invasion (PNI), and pretreatment prostate specific antigen levels. The pathology of every patient is reviewed at FCCC to confirm a diagnosis of malignancy. The objective of this study was to define differences between pathologic reviews and their impact on treatment between outside institutions and FCCC.

METHODS

The authors reviewed 538 pathology reports of prostate biopsies performed at both outside pathology departments and FCCC on patients evaluated between January 1993 and December 1996. The outside pathology reviews represented 107 community hospitals, academic institutions, and private pathology laboratories. Patients who had received hormonal therapy, cryosurgery, or radical prostatectomy prior to prostate biopsy were excluded from analysis. Final FCCC pathology determinations were compared with pathology reports from outside institutions. Reports then were analyzed to determine whether differences in interpretation would have resulted in different treatment strategies. Differences in percentages according to institutional type were evaluated using the chi-square statistic. The cost was assessed and cost per change in treatment estimated.

RESULTS

The 538 pathology reviews identified a nearly 40% change in GS and a 13% change in > or =2 GS between the FCCC pathology review and 107 outside academic institutions. The results of this study showed that 22% of community hospitals, 10% of private laboratories, and 8% of academic institutions demonstrated at least 2 GS changes compared with the FCCC pathology review (p = 0.001). There was no significant difference observed between types of institutions in the incidence of PNI.

CONCLUSIONS

This analysis provides evidence of a significant difference in the pathologic reviews of prostate biopsies conducted at FCCC and outside pathology departments. There was a nearly 40% change in GS and a 13% change in > or =2 GS between the FCCC pathology review and 107 outside institutions. The second pathology review added approximately $104 per case for a total of $55,952 to review all 538 cases. Overall, the savings in health care dollars resulting from the second pathologic review totaled $12,997. This second review of outside pathology in prostate cancer appears to be justified based on the treatment changes and on cost.

Accuracy of biopsy Gleason scores from a large uropathology laboratory: use of a diagnostic protocol to minimize observer variability

OBJECTIVES

To examine the correlation of biopsy Gleason scores with radical prostatectomy specimens from a laboratory that uses protocols designed to minimize observer variability. This protocol mandates consensus case review of all nonbenign cases.

METHODS

Between August 24, 1993 and June 26, 1997, 106 patients who underwent radical prostatectomy at Johns Hopkins Hospital, Baltimore, Maryland had their prostate cancer diagnosed and graded at one laboratory (DIANON Systems). We analyzed the Gleason scores from the biopsy and radical prostatectomy specimens.

RESULTS

Exact correlation existed between biopsy and radical prostatectomy Gleason scores for 72 (68%) cases; 103 (97%) correlated within 1 grade, all cases correlated within 2 grades; 26 (25%) biopsies were undergraded and 8 (8%) were overgraded. Positive predictive values for biopsy Gleason scores 5, 6, and 7 were 66%, 67%, and 71%, respectively. Grouped Gleason scores (well differentiated [2 to 4], moderately differentiated [5, 6], moderately to poorly differentiated [7], and poorly differentiated [8 to 10]) correlated exactly for 74 (70%) cases and within 1 group for all cases. Patient age, digital rectal examination results, total number of positive cores, and maximum percentage of tumor on biopsy did not affect correlation, but prostate-specific antigen (PSA) levels did affect correlation (exact correlation 96% when the PSA level was less than 5 ng/mL; 50% when the PSA level was 11 ng/mL or greater, P <0.01).

CONCLUSIONS

The combination of experience and the protocol described minimizes intra- and interobserver variability, thereby improving the predictive value of biopsy Gleason grading. Biopsy and radical prostatectomy Gleason scores correlate more poorly when the PSA level is high (11 ng/mL or greater) than when the PSA level is low (less than 5 ng/mL).

Minimal criteria for the diagnosis of prostate cancer on needle biopsy

Increased clinical screening of men at risk for prostate cancer, and the realization of the benefits of performing multiple biopsies per prostate, have facilitated early detection of malignancy, while presenting the pathologist with a growing array of diagnostic findings. Interpretation of these findings requires discussion of the minimal criteria required for the diagnosis of cancer on needle biopsy within a wide spectrum of related histologic findings. This spectrum includes small acinar proliferations suspicious for but not diagnostic of cancer, benign mimics of cancer, the preinvasive entity of high-grade prostatic intraepithelial neoplasia, and various treatment effects. Clinical implications of these findings and other prognostic factors are detailed.

Predictive accuracy of transrectal ultrasound-guided prostate biopsy: correlations to matched prostatectomy specimens

OBJECTIVES

To characterize observed differences in Gleason score between prostate biopsy and corresponding radical retropubic prostatectomy (RRP) specimens.

METHODS

One hundred consecutive clinically localized prostate cancers diagnosed by transrectal ultrasound-guided biopsy (TRUS-Bx) and treated with RRP were reviewed. All specimens were evaluated in blinded review by a single expert uropathologist and contrasted with the initial histologic analysis, performed by multiple pathologists.

RESULTS

Mean Gleason score of TRUS-Bx specimens for blinded review and at initial evaluation were 6.6 +/- 0.1 and 6.0 +/- 0.1 (P < 0.001). Corresponding RRP values were 6.8 +/- 0.1 and 6.5 +/- 0.1 (P < 0.03). Differences in Gleason score between TRUS-Bx and RRP at initial evaluation were significant (P < 0.02), but not in blinded review (P = NS). In blinded review, TRUS-Bx correctly predicted RRP histology for 88% of men with lesions scored as Gleason 5 to 7 and 41% of men with well-(Gleason score of 2 to 4) or poorly differentiated (Gleason score of 8 to 10) lesions (P < 0.01).

CONCLUSIONS

TRUS-Bx does not accurately reflect RRP histology when predicting well- or poorly differentiated lesions. Prostate cancer treatment algorithms should not be predicated upon biopsy histology alone. Histologic interpretation is more accurate and precise when performed by a single experienced uropathologist.

The diagnosis and reporting of adenocarcinoma of the prostate in core needle biopsy specimens

BACKGROUND

There has been relatively little written on the diagnosis and reporting of adenocarcinoma of the prostate diagnosed in core needle biopsy specimens.

METHODS

This article reviews issues concerning diagnosing, grading, and quantification of prostate carcinoma in core needle biopsy specimens.

RESULTS

The diagnosis of prostate carcinoma in core needle biopsy specimens is discussed, including the relative frequency and utility of various architecture, cytologic, and ancillary features. Grading of prostate carcinoma in core needle biopsy specimens is evaluated along with the relationship of core needle biopsy grade to corresponding radical prostatectomy grade. The relationship between the extent of carcinoma in core needle biopsy specimens to extent of tumor in the radical prostatectomy is summarized. Finally, this article summarizes articles supporting the use of high molecular weight cytokeratin in the diagnosis of adenocarcinoma of the prostate in core needle biopsy specimens.

CONCLUSIONS

Pathologists are not only called upon to diagnose limited cancer in core needle biopsy specimens, but also to quantify and grade these cancers accurately. Issues relating to this pathologic evaluation are critical for physicians treating men with adenocarcinoma of the prostate.