The value of the 2005 International Society of Urological Pathology (ISUP) modified Gleason grading system as a predictor of biochemical recurrence after radical prostatectomy

Comparative Pathobiology of Canine and Human Prostate Cancer: State of the Art and Future Directions

First described in 1817, prostate cancer is considered a complex neoplastic entity, and one of the main causes of death in men in the western world. In dogs, prostatic carcinoma (PC) exhibits undifferentiated morphology with different phenotypes, is hormonally independent of aggressive character, and has high rates of metastasis to different organs. Although in humans, the risk factors for tumor development are known, in dogs, this scenario is still unclear, especially regarding castration. Therefore, with the advent of molecular biology, studies were and are carried out with the aim of identifying the main molecular mechanisms and signaling pathways involved in the carcinogenesis and progression of canine PC, aiming to identify potential biomarkers for diagnosis, prognosis, and targeted treatment. However, there are extensive gaps to be filled, especially when considering the dog as experimental model for the study of this neoplasm in humans. Thus, due to the complexity of the subject, the objective of this review is to present the main pathobiological aspects of canine PC from a comparative point of view to the same neoplasm in the human species, addressing the historical context and current understanding in the scientific field.

Prostate imaging features that indicate benign or malignant pathology on biopsy

Accurate diagnosis of clinically significant prostate cancer is essential in identifying patients who should be offered treatment with curative intent. Modifications to the Gleason grading system in recent years show that accurate grading and reporting at needle biopsy can improve identification of clinically significant prostate cancers. Extracapsular extension of prostate cancer has been demonstrated to be an adverse prognostic factor with greater risk of metastatic spread than organ-confined disease. Tumor volume may be an independent prognostic factor and should be considered in conjunction with other factors. Multi-parametric magnetic resonance imaging (MP-MRI) has become an increasingly important tool in the diagnosis and characterization of prostate cancer. MP-MRI allows T2-weighted (T2W) anatomical imaging to be combined with functional and physiological assessment. Diffusion-weighted imaging (DWI) has shown greater sensitivity, specificity and negative predictive value compared to prostate specific antigen (PSA) testing and T2W imaging alone and has a more positive correlation with Gleason score and tumour volume. Dynamic gadolinium contrast-enhanced (DCE) imaging can exhibit difficulties in distinguishing prostatitis from malignancy in the peripheral zone, and between benign prostatic hyperplasia (BPH) and malignancies in the transition zone (TZ). Computer aided diagnosis utilizes software to aid radiologists in detecting and diagnosing abnormalities from diagnostic imaging. New techniques of quantitative MRI, such as VERDICT MRI use tissue-specific factors to delineate different cellular and microstructural phenotypes, characterizing tissue properties with greater detail. Proton MR spectroscopic imaging (MRSI) is a more technically challenging imaging modality than DCE and DWI MRI. Over the last decade, choline and prostate-specific membrane antigen (PSMA) positron emission tomography (PET) have developed as better tools for staging than conventional imaging. While hyperpolarized MRI shows promise in improving the imaging and differentiation of benign and malignant lesions there is further work required. Accurate reading and interpretation of diagnostic investigations is key to accurate identification of abnormal areas requiring biopsy, sparing those in whom benign or indolent disease can be managed by non-invasive means. Embracing and advancing existing technologies is essential in furthering this process.

Validation of the WHO 2016 new Gleason score of prostatic carcinoma

Context

New Gleason Score of Prostate.

Aims

The aim of this study is to assign the patients with carcinoma prostate into new prognostic grade groups (PGGs) based on revised Gleason score (GS) and follow-up according to the WHO 2016.

Subjects and Methods

All the biopsies/resected specimens of carcinoma prostate from January 2014 to June 2016 were reviewed, and GS was done according to the WHO 2016. Accordingly, cribriform, fused, and glomeruloid glands were assigned GS 4. Thus, two groups were identified with GS 7 (3 + 4 and 4 + 3). The patients were grouped into PGGs 1-5. The number of patients with change in the prognostic group along with follow-up was calculated.

Results

There were 143 patients with carcinoma prostate, with a median age of 65 years. The initial GS was revised, and there was a decrease in GS 3 + 4 from 13.9% to 9% and increase in 4 + 3 from 19.6% to 23.8%. There was upgradation of PGG in 11 (7.69%) biopsies; with PGG from 1 to 2 in one; 2to 3 in eight; and 3to 4 in two. Follow-up at 2 years in 22 showed the poor prognoses in the patients who were upgraded to the higher prognostic group.

Conclusions

A change in PGG according to the WHO 2016 criteria was assigned in 7.69% biopsies of carcinoma prostate, and it correlated with prognosis.

Long-term costs and survival of prostate cancer: a population-based study

PURPOSE

There is a rising interest in measuring the societal burden of malignancies including prostate cancer. However, population-based studies reporting incidence costs of prostate cancer in the long term are lacking in Europe. The objectives of the study are to analyse the long-term costs and survival of prostate cancer patients treated by radical prostatectomy (RP) or conservative management (nRP).

METHODS

A retrospective claims data analysis of the National Health Insurance Found Administration of Hungary between 01.01.2002 and 31.10.2013 was carried out. Annual incidence costs related to prostate cancer and overall survival were calculated for a cohort of patients diagnosed between 2002 and 2005.

RESULTS

Altogether 17,642 patients were selected; 2185 (12%) of them have undergone RP. The annual incidence rate ranged between 4177 and 4736 cases. Mean age of RP and nRP patients was 59.4 (SD 5.9) and 71.0 (8.4) years, respectively. The mean survival time of the RP patients was significantly longer compared to nRP patients both in the total sample (11.2 vs. 7.4 years; p < 0.001) and in the subgroup <70 years (11.3 vs. 8.8 years; p < 0.001). At the end of the 12-year follow-up, RP patients had a higher (0.83 vs. 0.68), while nRP patients had a slightly lower (0.35 vs. 38) probability of being alive compared with the age-matched general male population. The long-term cumulative costs of the RP and nRP patients amounted to €4448 and €8616. The main driver of the cost difference was the high drug costs in the nRP group.

CONCLUSIONS

To our knowledge, this study applied the longest time-window in reporting population-based incidence costs in Europe. We found that not only RP patients lived longer but they had significantly lower total long-term costs than nRP patients. Therefore, radical prostatectomy is a cost-effective strategy in prostate cancer.

The prognostic significance of the 2014 International Society of Urological Pathology (ISUP) grading system for prostate cancer

The 2005 International Society of Urological Pathology (ISUP) modified Gleason grading system was further amended in 2014 with the establishment of grade groupings (ISUP grading). This study examined the predictive value of ISUP grading, comparing results with recognised prognostic parameters.Of 3700 men undergoing radical prostatectomy (RP) reported at Aquesta Pathology between 2008 and 2013, 2079 also had a positive needle biopsy available for review. We examined the association between needle biopsy 2014 ISUP grade and 2005 modified Gleason score, tumour volume, pathological stage of the subsequent RP tumour, as well as biochemical recurrence-free survival (BRFS). The median age was 62 (range 32-79 years). Median serum prostate specific antigen was 5.9 (range 0.4-69 ng/mL). For needle biopsies, 280 (13.5%), 1031 (49.6%), 366 (17.6%), 77 (3.7%) and 325 (15.6%) were 2014 ISUP grades 1-5, respectively. Needle biopsy 2014 ISUP grade showed a significant association with RP tumour volume (p < 0.001), TNM pT and N stage (p < 0.001) and BRFS (p < 0.001). Multivariate analysis using Cox proportional hazards regression model showed serum prostate specific antigen (PSA) at the time of diagnosis and ISUP grade >2 to be significantly associated with BRFS.This study provides evidence of the prognostic significance of ISUP grading for thin core needle biopsy of prostate.

Validation of International Society of Urological Pathology (ISUP) grading for prostatic adenocarcinoma in thin core biopsies using TROG 03.04 'RADAR' trial clinical data

In 2014 a consensus conference convened by the International Society of Urological Pathology (ISUP) adopted amendments to the criteria for Gleason grading and scoring (GS) for prostatic adenocarcinoma. The meeting defined a modified grading system based on 5 grading categories (grade 1, GS 3+3; grade 2, GS 3+4; grade 3, GS 4+3; grade 4, GS 8; grade 5, GS 9-10). In this study we have evaluated the prognostic significance of ISUP grading in 496 patients enrolled in the TROG 03.04 RADAR Trial. There were 19 grade 1, 118 grade 2, 193 grade 3, 88 grade 4 and 79 grade 5 tumours in the series, with follow-up for a minimum of 6.5 years. On follow-up 76 patients experienced distant progression of disease, 171 prostate specific antigen (PSA) progression and 39 prostate cancer deaths. In contrast to the 2005 modified Gleason system (MGS), the hazards of the distant and PSA progression endpoints, relative to grade 2, were significantly greater for grades 3, 4 and 5 of the 2014 ISUP grading scheme. Comparison of predictive ability utilising Harrell's concordance index, showed 2014 ISUP grading to significantly out-perform 2005 MGS grading for each of the three clinical endpoints.

From Gleason to International Society of Urological Pathology (ISUP) grading of prostate cancer

Gleason grading of prostate cancer has gained worldwide acceptance since its introduction 50 years ago. This system has fulfilled the role of a powerful prognostic indicator for many years and this has influenced treatment. There have been numerous changes to the management and diagnosis of prostate cancer since 1966, including prostate-specific antigen screening, resulting in the early detection of prostate cancer, This has resulted in the evolution of Gleason grading with the informal adoption of a number of alterations. Significant changes to Gleason grading were made in 2005 through a consensus conference convened by the International Society of Urological Pathology (ISUP). In more recent times, the necessity for further changes to prostate cancer grading has been apparent and a follow-up ISUP consensus conference was held in 2014. Changes resulting from this conference included the classifying of all cribriform cancer and glomeruloid patterns as Gleason grade 4, the grading of mucinous adenocarcinoma based on underlying architecture rather than uniformly considering these tumors as pattern 4, and the introduction of a Gleason score (GS)-based 5 grade system, which incorporated the 2014 modifications to the Gleason grading system. Designated ISUP grade, this system consists of five grades: grade 1 (GS ≤3 + 3), grade 2 (GS 3 + 4), grade 3 (GS 4 + 3), grade 4 (GS 4 + 4, 3 + 5, 5 + 3) and grade 5 (GS 9-10). With further advances recently reported in the literature, it is apparent that amendments to the current system are likely to be necessary in the future.

The evolving Gleason grading system

The Gleason grading system for prostate adenocarcinoma has evolved from its original scheme established in the 1960s-1970s, to a significantly modified system after two major consensus meetings conducted by the International Society of Urologic Pathology (ISUP) in 2005 and 2014, respectively. The Gleason grading system has been incorporated into the WHO classification of prostate cancer, the AJCC/UICC staging system, and the NCCN guidelines as one of the key factors in treatment decision. Both pathologists and clinicians need to fully understand the principles and practice of this grading system. We here briefly review the historical aspects of the original scheme and the recent developments of Gleason grading system, focusing on major changes over the years that resulted in the modern Gleason grading system, which has led to a new "Grade Group" system proposed by the 2014 ISUP consensus, and adopted by the 2016 WHO classification of tumours of the prostate.

Review by urological pathologists improves the accuracy of Gleason grading by general pathologists

Backgrounds

Urologists use biopsy Gleason scores for patient counseling, prognosis prediction, and decision making. The accuracy of Gleason grading is very important. However, the variability of Gleason grading between general pathologists cannot be overlooked. Here we evaluate the discrepancy in the Gleason grading between 2 urologic pathologists and general pathologists as well as improvement in the accuracy of Gleason grading by general pathologists as a result of review by urologic pathologists.

Methods

The subjects enrolled in the study were 755 patients who underwent prostate needle biopsy at affiliate hospitals of Nara Medical University over a period of 2 years. The biopsy samples were diagnosed by general pathologists. All biopsy samples were sent to Nara Medical University where they were diagnosed by 2 urologic pathologists. The results were then returned to the general pathologists. We compared the diagnostic accuracy of the general pathologists with that of the urologic pathologists for the parameters of no malignancy, atypical small acinar proliferation, high grade prostatic intraepithelial neoplasia and Gleason score (6, 3 + 4, 4 + 3 and 8–10). We then evaluated the concordance rate between the general and urologic pathologists for each of four consecutive 6-month periods.

Results

The overall concordance rate of urologic pathologists and general pathologists in the first, second, third and last 6-month periods was 71.8 % (140/198), 79.8 % (168/225), 89.7 % (166/185) and 89.9 % (133/148), respectively. The concordance rate of the Gleason score between urologic pathologists and general pathologists in the first, second, third and last 6-month periods was 47.5 %(38/80), 62.6 %(57/91),76.9 %(50/65) and 78.7 %(48/61), respectively, and the kappa value was 0.55, 0.68, 0.81 and 0.84, respectively. The concordance rate improved significantly over the course of each period (P = 0.04).

Conclusion

The concordance rate of the Gleason grading between the general pathologists and the urologic pathologists was 47.5 %. However, improvement of the concordance rate as a result of review by the urological pathologist could be seen.

Gleason underestimation is predicted by prostate biopsy core length

PURPOSE

To evaluate whether core length impacts biopsy accuracy and Gleason score underestimation compared to radical prostatectomy (RP) specimens.

METHODS

From 2010 to 2011, 8,928 cores were trans-rectal obtained from 744 consecutive patients (178 RP, 24%), 557 by an experienced performer (>250/year) and 187 (25%) by in-training urology residents. Prospectively analyzed variables were core length, age, prostate volume, free and total prostate-specific antigen (PSA), PSA density and free/total PSA ratio.

RESULTS

Mean core length for Gleason upgrading on RP (42.7%, n = 76) was 11.61 (±2.5, median 11.40) compared to 13.52 (±3.2, median 13.70), p < 0.001 for perfect biopsy-RP Gleason agreement (57.3%, n = 102). In multivariate analysis, for each unit of core length increment in millimeter, the Gleason upgrading risk decreased 89.9%, p = 0.049 [odds ratio (OR) 0.10, 95% confidence interval (CI) 0.01-0.99]. Biopsy positivity between experienced (35.5%) and in-training performer (30.1%) was not significantly different (p = 0.20), with comparable mean patient age (65.1 vs. 64.1), prostate volume (52.3 vs. 50.7) and median PSA (5.2 vs. 5.1), respectively. Denoting wider variability in terms of core length, in-training performers obtained significantly larger cores for positive biopsies (11.33 ± 3.42 vs. 10.83 ± 3.68), p = 0.043, compared to experienced performer (11.39 ± 3.36 vs. 11.37 ± 3.64), p = 0.30. In multivariate analysis, PSA density (OR 1.14, 95% CI 1.02-1.28) and age (OR 1.04, 95% CI 1.01-1.07) were significantly associated with biopsy positivity, p = 0.021 and p = 0.011, respectively.

CONCLUSION

While core length on trans-rectal biopsy independently affects Gleason upgrading on RP specimens, performer experience has minor impact on Gleason discordance or biopsy positivity due to a sharp learning curve.

Revised Gleason grading system is a better predictor of indolent prostate cancer at the time of diagnosis: retrospective clinical-pathological study on matched biopsy and radical prostatectomy specimens

INTRODUCTION/BACKGROUND

The increase of prostate cancer diagnosis after the introduction of prostate-specific antigen (PSA) screening resulted in overtreatment of patients with low risk tumors. The histological Gleason score (GS) revised in 2005 by the International Society of Urological Pathology (ISUP) is currently the most reliable tool to separate aggressive from indolent prostate cancer.

MATERIALS AND METHODS

Using the new 2005 GS criteria we retrospectively evaluated biopsy and surgical samples of 1344 patients who underwent radical prostatectomy in our institution. According to the new GS criteria we then selected 134 patients who would have been suitable for active surveillance at the time of biopsy (at least 2 positive cores, PSA < 10 ng/mL, GS ≤ 6). We finally assessed the accuracy of the revised GS in biopsy to predict indolent cancer in the prostatectomy specimens.

RESULTS

The mean GS increased from 6 to 7 after histological revision in biopsy and prostatectomy specimens. Histological revision determined a significant decrease of patients with GS ≤ 6 and an increase of those with GS ≥ 7 (all P < .001). The average of pathologically indolent disease (organ-confined, GS ≤ 6 at surgery, tumor of any volume) significantly decreased after histological revision (P < .001).

CONCLUSION

The revised ISUP 2005 criteria for Gleason grading provided better stratification of GS ≤ 6 prostate cancer and improved the accuracy for the histological diagnosis of indolent prostate cancer in biopsy and radical prostatectomy specimens.