The significance of modified Gleason grading of prostatic carcinoma in biopsy and radical prostatectomy specimens

Gleason score 7 prostate cancer on needle biopsy: relation of primary pattern 3 or 4 to pathological stage and progression after radical prostatectomy

PURPOSE

There have been only a few contradictory publications assessing whether Gleason score 4 + 3 = 7 has a worse prognosis than 3 + 4 = 7 on biopsy material in predicting pathological stage and biochemical recurrence. Older studies predated the use of the modified Gleason grading system established in 2005.

MATERIALS AND METHODS

We retrospectively studied 1,791 cases of Gleason score 7 on prostatic biopsy to determine whether the breakdown of Gleason score 7 into 3 + 4 vs 4 + 3 has prognostic significance in the modern era.

RESULTS

There was no difference in patient age, preoperative serum prostate specific antigen, maximum tumor percent per core or the number of positive cores between Gleason score 3 + 4 = 7 and Gleason score 4 + 3 = 7. Gleason score 4 + 3 = 7 showed an overall correlation with pathological stage (organ confined, focal extraprostatic extension, nonfocal extraprostatic extension, seminal vesicle invasion/lymph node metastases, p = 0.005). On multivariate analysis Gleason score 4 + 3 = 7 (p = 0.03), number of positive cores (p = 0.002), maximum percent of cancer per core (p = 0.006) and preoperative serum prostate specific antigen (p = 0.03) all correlated with pathological stage. Gleason score 4 + 3 = 7 on biopsy was also associated with an increased risk of biochemical progression after radical prostatectomy (p = 0.0001). On multivariate analysis Gleason score 4 + 3 = 7 (p = 0.001), maximum percent of cancer per core (p <0.0001) and preoperative serum prostate specific antigen (p <0.0001) but not number of positive cores correlated with the risk of biochemical progression after radical prostatectomy.

CONCLUSIONS

Our study further demonstrates that Gleason score 7 should not be considered a homogenous group for the purposes of disease management and prognosis.

Current perspectives on Gleason grading of prostate cancer

The 5-tier Gleason grading system for prostate cancer, introduced in 1966, has been proven to be one of the main independent predictors of prostate cancer outcome. This review addresses interobserver concordance in Gleason grading; the persistence of grading discrepancies with frequent upgrading from the biopsy to the prostatectomy specimen; the 2005 International Society of Urologic Pathologists' modifications to Gleason grading; the impact of this modified grading on grade migration and outcome prediction; and molecular correlates of cancer morphology. Data from the most recent years are emphasized.

Interactive digital slides with heat maps: a novel method to improve the reproducibility of Gleason grading

Our aims were to analyze reporting of Gleason pattern (GP) 3 and 4 prostate cancer with the ISUP 2005 Gleason grading and to collect consensus cases for standardization. We scanned 25 prostate biopsy cores diagnosed as Gleason score (GS) 6-7. Fifteen genitourinary pathologists graded the digital slides and circled GP 4 and 5 in a slide viewer. Grading difficulty was scored as 1-3. GP 4 components were classified as type 1 (cribriform), 2 (fused), or 3 (poorly formed glands). A GS of 5-6, 7 (3 + 4), 7 (4 + 3), and 8-9 was given in 29%, 41%, 19%, and 10% (mean GS 6.84, range 6.44-7.36). In 15 cases, at least 67% of observers agreed on GS groups (consensus cases). Mean interobserver weighted kappa for GS groups was 0.43. Mean difficulty scores in consensus and non-consensus cases were 1.44 and 1.66 (p = 0.003). Pattern 4 types 1, 2, and 3 were seen in 28%, 86%, and 67% of GP 4. All three coexisted in 16% (11% and 23% in consensus and non-consensus cases, p = 0.03). Average estimated and calculated %GP 4/5 were 29% and 16%. After individual review, the experts met to analyze diagnostic difficulties. Areas of GP 4 and 5 were displayed as heat maps, which were helpful for identifying contentious areas. A key problem was to agree on minimal criteria for small foci of GP 4. In summary, the detection threshold for GP 4 in NBX needs to be better defined. This set of consensus cases may be useful for standardization.

Epstein criteria for insignificant prostate cancer

Study Type - Prognosis (systematic review).

LEVEL OF EVIDENCE

2b. What's known on the subject? and What does the study add? Overtreatment of prostate cancer is a major problem in contemporary urological practice. The Epstein Criteria reduces overtreatment by identifying insignificant prostate cancers that may be amenable to surveillance therapy. This systematic review of the Epstein Criteria validation studies provides a collective insight into the application and accuracy of the Epstein Criteria to predict for insignificant prostate cancer across different institutions and geographies.

OBJECTIVE

• To review the accuracy of the Epstein Criteria for insignificant prostate cancer and to explore the effect of the modified Gleason classification system on this system.

METHODS

• We searched PubMed, EMBASE and the Cochrane Database using search terms 'Epstein Criteria', 'Prostate Cancer', 'Validation' and 'Insignificant Cancer' between 1994 to 2010 for validation articles. • These were divided into pre-2005 and post-2005 and concordances for organ-confined status, Gleason score ≤ 6 and insignificant cancer were analysed.

RESULTS

• A pre-2005 study showed concordance for insignificant prostate cancer, Gleason score ≤ 6 and organ-confined status at 84%, 90.3% and 91.6%, respectively. • Five post-2005 validation studies were concordant for insignificant cancer, Gleason score ≤ 6 and organ-confined status at 37-76%, 54.3-75.9% and 80.0-96.9%, respectively.

CONCLUSIONS

• The Epstein Criteria has a suboptimal accuracy for predicting for insignificant prostate cancer. • The modification to Gleason scoring may be responsible for a reduced accuracy over time. • However, significant heterogeneity in the validation studies means better quality validation studies are required.

Gleason score concordance on biopsy-confirmed prostate cancer: is pathological re-evaluation necessary prior to radical prostatectomy?

OBJECTIVES

• Gleason sum from prostate biopsy (bGS) is an important tool in classifying severity of disease, ultimately influencing clinical management. • Commonly, pathology specimens are re-evaluated internally prior to surgery. • We evaluate agreement of bGS with prostatectomy Gleason sum (pGS) and the impact of re-grading on prediction of true underlying tumor architecture.

MATERIALS AND METHODS

• Retrospective analysis of men who underwent robotic-assisted radical prostatectomy (RARP) by two surgeons from 2005-2009. Initial transrectal ultrasound (TRUS) biopsy demonstrated carcinoma at an outside lab. Specimens were re-evaluated by our GU pathologists prior to surgery. Biopsy data were correlated with pGS. • Kappa (κ) statistics for agreement and linear regression analyses were used for categorical variables. Coefficient of concordance was used for continuous variables.

RESULTS

• 100 patients had 331 positive biopsies. Agreement (κ) for bGS between outside labs and our pathologists was 0.55 (p < 0.001). • Internal read was twice as likely to upgrade vs. downgrade outside bGS (23% vs. 11%). • When re-evaluation resulted in a change in bGS, agreement with pGS was κ= 0.29, vs. κ=-0.04 for agreement of initial (outside) bGS with pGS. • When no change was made to bGS, agreement with pGS was κ= 0.40 (p < 0.001).

CONCLUSION

• Good reproducibility seen between outside labs and our institution on bGS. Internal pathology re-reads correlated better with pGS than original community bGS. When re-reads result in a change in bGS, there is a marked improvement in prediction of underlying tumor architecture confirming the value of re-evaluating all external biopsies prior to definitive surgery.

Gleason score correlation between biopsy and prostatectomy specimens and prediction of high-grade Gleason patterns: significance of central pathologic review

OBJECTIVES

To investigate the significance of dedicated central pathologic review for Gleason score (GS) correlation between the biopsy and radical prostatectomy (RP) specimens and the prediction of high-grade Gleason patterns. A discrepancy in the GS between the biopsy and RP specimens has been reported.

METHODS

The Clinicopathological Research Group for Localized Prostate Cancer disease registry collated the data from 1629 patients who had undergone RP from 1997 to 2005. All biopsy and RP specimens were retrospectively re-evaluated by 2 central uropathologists according to the International Society of Urological Pathology consensus. The GS correlation between the biopsy and RP specimens and the presence of high-grade Gleason patterns (4 or 5) were recorded. The GS was categorized into 5 groups (2-4, 5-6, 3 + 4, 4 + 3, and 8-10).

RESULTS

Central review significantly increased the exact concordance rate and decreased the undergrading and overgrading rates between the biopsy and RP specimens compared with local review (P < .05 for all). In each GS or prostate-specific antigen group, the central review biopsy GS had a significantly greater exact concordance rate with the RP specimen GS compared with the local review biopsy GS (P < .05 for all). Regarding high-grade Gleason patterns in the RP specimens, central review showed significantly greater sensitivity, positive predictive value, and negative predictive value than local review (P < .05 for all).

CONCLUSIONS

We have demonstrated that central review using the International Society of Urological Pathology consensus improves the GS correlation and better predicts high-grade Gleason patterns compared with local review. We recommend central pathologic review by dedicated uropathologists for multi-institutional studies using data from prostate biopsy and RP specimens.

Clinical implications of changing definitions within the Gleason grading system

Remarkably, more than 40 years after the inception of the Gleason grading system, it remains one of the most powerful prognostic predictors in prostate cancer. Gleason's original grading system, however, has undergone significant revision over the years, first by Gleason and his colleagues, and most recently at the 2005 International Society of Urological Pathology Consensus Conference. The consensus conference and subsequent articles proposing further modifications have helped pathologists to adapt the Gleason grading system to current urologic practice in a uniform manner. The changing definitions of Gleason pattern 3 and 4 prostatic adenocarcinoma have tended to narrow the scope of pattern 3 carcinoma and widen the scope of pattern 4 carcinoma. These modifications have had an important role in improving the inter-observer reproducibility of the Gleason system. Whether these changes have a significant impact on the clinical treatment of prostate cancer remains to be seen. However, as many of these modifications are supported only by a few studies, long-term follow-up studies with clinical end points are essential to validate these recommendations.

The impact of the 2005 International Society of Urological Pathology (ISUP) consensus on Gleason grading in contemporary practice

AIMS

To investigate the impact of the 2005 International Society of Urological Pathology (ISUP) Gleason grading consensus in contemporary practice.

METHODS AND RESULTS

The Gleason scores (GS) were compared in two consecutive patient cohorts with matched biopsies and prostatectomies: (i) 908 patients evaluated before the ISUP consensus (July 2000-June 2004) and (ii) 423 patients evaluated after the ISUP consensus (October 2005-June 2007). All biopsies and prostatectomies were performed and scored in one institution and were sampled and processed identically. There was a higher percentage of biopsy and prostatectomy specimens with GS > or = 7 after the ISUP consensus (GS > or = 7 on biopsy in 32% before ISUP versus 46% after ISUP; GS > or = 7 on prostatectomy in 53% before ISUP versus 68% after ISUP; P < 0.001). No significant difference in the complete and + or -1 unit Gleason agreement was found before and after the ISUP consensus. There was a trend towards better complete agreement for GS > or = 7 after the ISUP consensus.

CONCLUSIONS

There was a shift towards higher GS on biopsy and prostatectomy in our practice after the ISUP consensus, although - there was no significant impact on the biopsy-prostatectomy Gleason agreement. The significance of this shift for patient management and prognosis is uncertain.

An update of the Gleason grading system

PURPOSE

An update is provided of the Gleason grading system, which has evolved significantly since its initial description.

MATERIALS AND METHODS

A search was performed using the MEDLINE(R) database and referenced lists of relevant studies to obtain articles concerning changes to the Gleason grading system.

RESULTS

Since the introduction of the Gleason grading system more than 40 years ago many aspects of prostate cancer have changed, including prostate specific antigen testing, transrectal ultrasound guided prostate needle biopsy with greater sampling, immunohistochemistry for basal cells that changed the classification of prostate cancer and new prostate cancer variants. The system was updated at a 2005 consensus conference of international experts in urological pathology, under the auspices of the International Society of Urological Pathology. Gleason score 2-4 should rarely if ever be diagnosed on needle biopsy, certain patterns (ie poorly formed glands) originally considered Gleason pattern 3 are now considered Gleason pattern 4 and all cribriform cancer should be graded pattern 4. The grading of variants and subtypes of acinar adenocarcinoma of the prostate, including cancer with vacuoles, foamy gland carcinoma, ductal adenocarcinoma, pseudohyperplastic carcinoma and small cell carcinoma have also been modified. Other recent issues include reporting secondary patterns of lower and higher grades when present to a limited extent, and commenting on tertiary grade patterns which differ depending on whether the specimen is from needle biopsy or radical prostatectomy. Whereas there is little debate on the definition of tertiary pattern on needle biopsy, this issue is controversial in radical prostatectomy specimens. Although tertiary Gleason patterns are typically added to pathology reports, they are routinely omitted in practice since there is no simple way to incorporate them in predictive nomograms/tables, research studies and patient counseling. Thus, a modified radical prostatectomy Gleason scoring system was recently proposed to incorporate tertiary Gleason patterns in an intuitive fashion. For needle biopsy with different cores showing different grades, the current recommendation is to report the grades of each core separately, whereby the highest grade tumor is selected as the grade of the entire case to determine treatment, regardless of the percent involvement. After the 2005 consensus conference several studies confirmed the superiority of the modified Gleason system as well as its impact on urological practice.

CONCLUSIONS

It is remarkable that nearly 40 years after its inception the Gleason grading system remains one of the most powerful prognostic factors for prostate cancer. This system has remained timely because of gradual adaptations by urological pathologists to accommodate the changing practice of medicine.

Will the modification of the Gleason grading system affect the urology practice?

The aim of the present study was to determine how the modified Gleason grading (mGG) system affects the score discrepancy between needle biopsy (NB) and radical prostatectomy (RP) and to investigate the effect of the modified scores on nomogram predictions. When the conventional Gleason grading (cGG) and mGG systems were compared, a new Gleason score was obtained in the NBs for 40 out of 97 patients (41.2%; P < .001) and in the RP specimens for 15 out of 97 patients (15.5%; P = .005). The agreement between the NBs and RP specimens rose from 31.9% to 44.3% with the mGG system (P = .017). However, when the predictions calculated with the location of modified Gleason scores in the Memorial Sloan Kettering Cancer Center nomogram were compared with those of the conventional Gleason scores, higher pathological stage and lower life expectancy predictions were obtained. Therefore, when a clinician is making a choice from therapeutic options, this change should be taken into account.

[Trends in prostate biopsy interpretation]

Driven by the pressure of increasing use of PSA screening, cancer diagnosis based on histopathology has been constantly improved. When appropriate quality standards for obtaining a biopsy specimen and for tissue preparation are upheld, even the smallest tumour foci can be identified with certainty. Efforts to standardize the Gleason grading should also help to render assessments of tumour biology more precise. In addition, subtle diagnosis of precancerous or cancer-associated lesions will permit more exact prognoses of existing cancer risk to be made. There are still weak points: reliable recognition of clinically insignificant carcinomas and the danger of overtreatment. Further research activity on this topic is needed.

Investigating FTIR based histopathology for the diagnosis of prostate cancer

Prostate cancer is the most common gender specific cancer. The current gold standard for diagnosis, histopathology, is subjective and limited by variation between different pathologists. The diagnostic problems associated with the correct grading and staging of prostate cancer (CaP) has led to an interest in the development of spectroscopic based diagnostic techniques. FTIR microspectroscopy used in combination with a Principal Component Discriminant Function Analysis (PC-DFA) was applied to investigate FTIR based histopathology for the diagnosis of CaP. In this paper we report the results of a large patient study in which FTIR has been proven to grade CaP tissue specimens to a high degree of sensitivity and specificity.

Interobserver agreement of Gleason score and modified Gleason score in needle biopsy and in surgical specimen of prostate cancer

INTRODUCTION

Gleason score, which has a high interobserver variability, is used to classify prostate cancer. The most recent consensus valued the tertiary Gleason pattern and recommended its use in the final score of needle biopsies (modified Gleason score). This pattern is considered to be of high prognostic value in surgical specimens. This study emphasized the evaluation of the modified score agreement in needle biopsies and in surgical specimen, as well as the interobserver variability of this score.

MATERIALS AND METHODS

Three pathologists evaluated the slides of needle biopsies and surgical specimens of 110 patients, reporting primary, secondary and tertiary Gleason patterns and after that, traditional and modified Gleason scores were calculated. Kappa test (K) assessed the interobserver agreement and the agreement between the traditional and modified scores of the biopsy and of the surgical specimen.

RESULTS

Interobserver agreement in the biopsy was K = 0.36 and K = 0.35, and in the surgical specimen it was K = 0.46 and K = 0.36, for the traditional and modified scores, respectively. The tertiary Gleason grade was found in 8%, 0% and 2% of the biopsies and in 8%, 0% and 13% of the surgical specimens, according to observers 1, 2 and 3, respectively. When evaluating the agreement of the traditional and modified Gleason scores in needle biopsy with both scores of the surgical specimen, a similar agreement was found through Kappa.

CONCLUSION

Contrary to what was expected, the modified Gleason score was not superior in the agreement between the biopsy score and the specimen, or in interobserver reproducibility, in this study.

Reproducibility and reliability of tumor grading in urological neoplasms

Histopathologic tumor grading reflects the degree of differentiation of a given tumor and for most urological tumors grading is an important factor in predicting their biological aggressiveness. Consequently, the clinical management of tumor patients is often strongly influenced by the tumor grade, provided by pathologists. This implicates that an ideal grading system should not only be of high prognostic relevance, but also of high reproducibility among different pathologists. To this end individual histological grading systems have been developed for different tumor entities and even for a given tumor type several grading systems have been proposed. All of these grading systems possess an inherent degree of subjectivity and consequently, both intra- and interobserver variability exist. In this review, grading systems for the most frequent urological tumors (i.e. prostate cancer, renal cell carcinoma, and urothelial tumors) are mentioned and data on the reproducibility and reliability of the most commonly used grading systems are summarized.