Grading of renal cell carcinoma

Multiphase comparative study for WHO/ISUP nuclear grading diagnostic model based on enhanced CT images of clear cell renal cell carcinoma

To compare and analyze the diagnostic value of different enhancement stages in distinguishing low and high nuclear grade clear cell renal cell carcinoma (ccRCC) based on enhanced computed tomography (CT) images by building machine learning classifiers. A total of 51 patients (Dateset1, including 41 low-grade and 10 high-grade) and 27 patients (Independent Dateset2, including 16 low-grade and 11 high-grade) with pathologically proven ccRCC were enrolled in this retrospective study. Radiomic features were extracted from the corticomedullary phase (CMP), nephrographic phase (NP), and excretory phase (EP) CT images, and selected using the recursive feature elimination cross-validation (RFECV) algorithm, the group differences were assessed using T-test and Mann-Whitney U test for continuous variables. The support vector machine (SVM), random forest (RF), XGBoost (XGB), VGG11, ResNet18, and GoogLeNet classifiers are established to distinguish low-grade and high-grade ccRCC. The classifiers based on CT images of NP (Dateset1, RF: AUC = 0.82 ± 0.05, ResNet18: AUC = 0.81 ± 0.02; Dateset2, XGB: AUC = 0.95 ± 0.02, ResNet18: AUC = 0.87 ± 0.07) obtained the best performance and robustness in distinguishing low-grade and high-grade ccRCC, while the EP-based classifier performance in poorer results. The CT images of enhanced phase NP had the best performance in diagnosing low and high nuclear grade ccRCC. Firstorder_Kurtosis and firstorder_90Percentile feature play a vital role in the classification task.

Validation of the World Health Organization/International Society of Urological Pathology grading for Chinese patients with clear cell renal cell carcinoma

Background

This study aimed to compare the World Health Organization/International Society of Urological Pathology (WHO/ISUP) grading system and the Fuhrman grading system and to verify the WHO/ISUP grade as a prognostic parameter of clear cell renal cell carcinoma (ccRCC) in a Chinese population.

Methods

The study consisted of 753 ccRCC patients treated with curative surgery between 2010 and 2018 at Xiangya Hospital Central South University (Changsha, China). All pathologic data were retrospectively reviewed by two pathologists. Cancer-specific survival (CSS) and recurrence-free survival (RFS) were examined as clinical outcomes.

Results

According to the WHO/ISUP grading system (ISUP group), nephrectomy type, pT stage and WHO/ISUP grade were independent risk factors for CSS (P<0.0001, P=0.0127 and P<0.0001, respectively) and RFS (P<0.0001, P=0.0077, and P<0.0001, respectively). In the Fuhrman group, nephrectomy type, pT stage and Fuhrman grade were independent risk factors for CSS (P<0.0001, P=0.0004, and P<0.0001, respectively) and RFS (P<0.0001, P=0.0001, and P<0.0001, respectively). The C-index for CSS and RFS using the Fuhrman grading system was 0.6323 and 0.6342, respectively, and that using the WHO/ISUP grading system was 0.6983 and 0.7005, respectively, both higher than the former (P=0.0185, and P=0.0172, respectively). In addition, upgrading from Fuhrman grade 2 to ISUP grade 3 resulted in worse CSS and RFS for ccRCC patients (P=0.0033 and P =0.0003, respectively).

Conclusions

We first verified correlations between the postoperative prognosis and WHO/ISUP grade of ccRCC in a Chinese population and confirmed that the ability to predict clinical outcomes with the WHO/ISUP grading system was superior to that with the Fuhrman grading system.

A CT-based deep learning model for predicting the nuclear grade of clear cell renal cell carcinoma

PURPOSE

To investigate the effects of different methodologies on the performance of deep learning (DL) model for differentiating high- from low-grade clear cell renal cell carcinoma (ccRCC).

METHOD

Patients with pathologically proven ccRCC diagnosed between October 2009 and March 2019 were assigned to training or internal test dataset, and external test dataset was acquired from The Cancer Genome Atlas-Kidney Renal Clear Cell Carcinoma (TCGA-KIRC) database. The effects of different methodologies on the performance of DL-model, including image cropping (IC), setting the attention level, selecting model complexity (MC), and applying transfer learning (TL), were compared using repeated measures analysis of variance (ANOVA) and receiver operating characteristic (ROC) curve analysis. The performance of DL-model was evaluated through accuracy and ROC analyses with internal and external tests.

RESULTS

In this retrospective study, patients (n = 390) from one hospital were randomly assigned to training (n = 370) or internal test dataset (n = 20), and the other 20 patients from TCGA-KIRC database were assigned to external test dataset. IC, the attention level, MC, and TL had major effects on the performance of the DL-model. The DL-model based on the cropping of an image less than three times the tumor diameter, without attention, a simple model and the application of TL achieved the best performance in internal (ACC = 73.7 ± 11.6%, AUC = 0.82 ± 0.11) and external (ACC = 77.9 ± 6.2%, AUC = 0.81 ± 0.04) tests.

CONCLUSIONS

CT-based DL model can be conveniently applied for grading ccRCC with simple IC in routine clinical practice.

Verification of the International Society of Urological Pathology recommendations in Japanese patients with clear cell renal cell carcinoma

The aim of the present study was to evaluate the validity of potential prognostic parameters of clear cell renal cell carcinoma (ccRCC) recommended by the 2012 International Society of Urological Pathology (ISUP) Consensus Conference in the Japanese population. We reviewed 406 Japanese patients with localized or locally advanced ccRCC who underwent curative surgery during 2004-2014 at Tokai University Hospital (Isehara, Japan) and were followed up for >2 years after surgery. A single pathologist reviewed all the histological slides. Morphological subtype and pathological T stage were reassigned according to the 2016 World Health Organization and TNM classifications. Sarcomatoid differentiation (SD), rhabdoid differentiation (RD), tumor necrosis (TN) and microvascular invasion (MVI) were assessed according to the 2012 ISUP recommendations. Nuclear grade was reclassified according to both the Fuhrman and the ISUP grading systems. Recurrence‑free survival (RFS) and cancer-specific survival (CSS) were assessed through univariate and multivariate analyses. According to the Fuhrman grading system (group Fuhrman), TN and MVI were independent risk factors for postoperative recurrence in the multivariate analysis using the Cox proportional hazards model. According to the ISUP grading system (group ISUP), TN and MVI were independent risk factors for postoperative recurrence. In group Fuhrman, age, Fuhrman grade and TN were independent risk factors for CSS. In group ISUP, age, ISUP grade, and TN were independent risk factors for CSS. Furthermore, the group that was upgraded from Fuhrman grade 2 to ISUP grade 3 exhibited poorer CSS compared with the group that was reclassified from Fuhrman grade 2 to ISUP grade 2 (non-upgraded). Regardless of the nuclear grade, TN remained an independent predictor of RFS and CSS. To the best of our knowledge, this is the first report to prove the correlation between the 2012 ISUP recommendations and clinical outcomes in a Japanese ccRCC cohort. TN and upgrading to ISUP grade 3 were found to be potentially useful independent indicators of postoperative prognosis.

The ISUP system of staging, grading and classification of renal cell neoplasia

There have been significant changes in the staging, classification and grading of renal cell neoplasia in recent times. Major changes have occurred in our understanding of extra-renal extension by renal cell cancer and how gross specimens must be handled to optimally display extra-renal spread. Since the 1981 World Health Organization (WHO) classification of renal tumors, in which only a handful of different entities were reported, many new morphological types have been described in the literature, resulting in 50 different entities reported in the 2004 WHO classification. Since 2004, further new entities have been recognized and reported necessitating an update of the renal tumor classification. There have also been numerous grading systems for renal cell carcinoma with Fuhrman grading, the most widely used system. In recent times, the prognostic value and the applicability of the Fuhrman grading system in practice has been shown to be, at best, suboptimal. To address these issues and to recommend reporting guidelines, the International Society of Urological Pathology (ISUP) undertook a review of adult renal neoplasia through an international consensus conference in Vancouver in 2012. The conduct of the conference was based upon evidence from the literature and the current practice amongst recognized experts in the field. Working groups selected to deal with key topics evaluated current data and identified points of controversy. A pre-meeting survey of the ISUP membership was followed by the consensus conference at which a formal ballot was taken on each key issue. A 65% majority vote was taken as consensus. This review summarizes the outcome and recommendations of this conference with regards to staging, classification and grading of renal cell neoplasia.

Clinical and pathological features associated with prognosis in patients with papillary renal cell carcinoma

PURPOSE

We determined the clinical and pathological features associated with death from papillary renal cell carcinoma in 395 surgically treated patients.

MATERIALS AND METHODS

Papillary renal cell carcinoma tissue slides from each patient were reviewed for type (1 or 2), grade, TNM stage, coagulative tumor necrosis and sarcomatoid differentiation. Associations of clinical and pathological features with death from renal cell carcinoma were evaluated using Cox proportional hazards regression models and summarized by the HR and 95% CI. Cancer specific survival was estimated using the Kaplan-Meier method.

RESULTS

Univariate analysis revealed that symptoms, tumor thrombus, tumor size, perinephric/renal sinus fat invasion, 2010 primary tumor classification, regional lymph node involvement, distant metastasis, 2010 TNM stage group, grade, tumor necrosis, sarcomatoid differentiation and papillary renal cell carcinoma type were associated with death from renal cell carcinoma. Grade was more strongly associated with death from renal cell carcinoma than papillary renal cell carcinoma type. Multivariate analysis indicated that symptoms, 2010 TNM stage group and grade jointly were significantly associated with death from renal cell carcinoma.

CONCLUSIONS

This large series of patients with papillary renal cell carcinoma reveals features associated with death from renal cell carcinoma and confirms that grade is more predictive of outcome than papillary renal cell carcinoma type.

Overexpression of cyclin-dependent kinase-associated protein phosphatase enhances cell proliferation in renal cancer cells

OBJECTIVE

The aim of this study was to understand the role of cyclin-dependent kinase-associated protein phosphatase (KAP) in renal cancer cell growth.

MATERIALS AND METHODS

Renal cell carcinoma (RCC) tissues from 58 patients receiving surgical resection were included for immunohistochemistry analysis. Additionally, human embryonic kidney (HEK293) cells overexpressing KAP were established for tumorigenicity experiments.

RESULTS

Clinicopathologic analysis indicated that poorly differentiated RCCs with a higher histological grade (grade 3/4) were associated with a higher proportion of KAP-positive cells (P < 0.001) as well as cytoplasmic expression of KAP (P < 0.05). HEK293 cells overexpressing KAP had a higher growth rate, greater resistance to TNF-α mediated increment of caspase 3 activity, a shorter cell cycle time, and greater ability of cell invasion. Tumorigenicity experiments showed that KAP-overexpressing cells generated significantly larger xenograft tumors in nude mice compared with mock controls (P = 0.032).

CONCLUSIONS

KAP expression was associated with poorly differentiated RCCs and overexpression of KAP in renal cells enhanced cell proliferation, resistance to apoptosis, invasive ability, and xenograft tumor formation.

Clinical impact of the presence of the worst nucleolar grade in renal cell carcinoma specimens

OBJECTIVE

Renal cell carcinoma (RCC) with a high-nucleolar-grade component is considered to be an aggressive type of tumor. In the present study, we evaluated the impact of the presence of the worst-nucleolar-grade component and also tried to determine predictors for recurrence and prognosis in patients with the worst grade component.

METHODS

We evaluated 314 patients with RCC. A three-graded system was used for nucleolar grading, the patients were classified into four groups according to the presence of the worst nucleolar grade (Grade 3) and the occupancy of each grade, and clinicopathological factors and clinical outcomes were compared. In patients of Grade 3 components (Groups 1 and 2), factors influencing on prognosis and recurrence were evaluated by multivariate analysis.

RESULTS

There was no significant difference in clinicopathological factors between Group 1 (with Grade 3-dominant tumors) and Group 2 (with tumors in which Grade 1 or 2 was dominant and there were Grade 3 components). Neither did cause-specific survival or recurrence-free survival differ significantly between those two groups. In multivariate analysis, only distant metastasis was an independent predictor for prognosis in all patients with Grade 3 components. Moreover, an elevated C-reactive protein (CRP) level (>or=1 mg/dl) was the only independent predictor of recurrence in N0M0 patients.

CONCLUSIONS

Regardless of dominancy, the presence of the worst grade component has a significant clinical impact in RCC patients. N0M0 patients whose RCC has worst-grade components but whose CRP levels are <1 are expected to have longer recurrence-free intervals and to survive longer than those whose CRP levels are higher.

Grade-dependent proteomics characterization of kidney cancer

Kidney cancer is frequently metastatic on presentation at which point the disease is associated with a 95% mortality. Assessment of tumor grade on pathological examination is the most powerful means for prognostication as well as for stratification of patients into those who might respond to conventional or targeted therapy. Although there exist several grading systems in common use, all suffer from significant disparity among observers. In an attempt to objectify this process as well as to acquire grade-specific mechanistic information, we performed LC-MS/MS-based proteomics analysis on 50 clear cell kidney cancers equally distributed among normal tissues and Fuhrman grades 1-4. Initial experiments confirmed the utility of using archived formalin-fixed paraffin-embedded samples for LC-MS/MS-based proteomics analysis, and the LC-MS/MS findings were validated by extensive immunoblotting. We now show that changes among many biochemical processes and pathways are strongly grade-dependent with the glycolytic and amino acid synthetic pathways highly represented. In addition, proteins relating to acute phase and xenobiotic metabolism signaling are highly represented. Self-organized mapping of proteins with similar patterns of expression led to the creation of a heat map that will be useful in grade characterization as well as in future research relating to oncogenic mechanisms and targeted therapies for kidney cancer.

Microarray-based identification of CUB-domain containing protein 1 as a potential prognostic marker in conventional renal cell carcinoma

PURPOSE

Renal cell carcinoma (RCC) is characterized by a variable and unpredictable clinical course. Thus, accurate prediction of the prognosis is important in clinical settings. We conducted microarray-based study to identify a novel prognostic marker in conventional RCC.

PATIENTS AND METHODS

The present study included the patients surgically treated at Kyoto University Hospital. Gene expression profiling of 39 samples was carried out to select candidate prognostic markers. Quantitative real-time PCR of 65 samples confirmed the microarray experiment results. Finally, we evaluated the significance of potential markers at their protein expression level by immunohistochemically analyzing 230 conventional RCC patients.

RESULTS

Using expression profiling analysis, we identified 14 candidate genes whose expression levels predicted unfavorable disease-specific survival. Next, we examined the expression levels of nine candidate genes by quantitative real-time PCR and selected CUB-domain containing protein 1 (CDCP1) for further immunohistochemical analysis. Positive staining for CDCP1 inversely correlated with disease-specific and recurrence-free survivals. In multivariate analysis including clinical/pathological factors, CDCP1 staining was a significant predictor of disease-specific and recurrence-free survivals.

CONCLUSIONS

We identified CDCP1 as a potential prognostic marker for conventional RCC. Further studies might be required to confirm the prognostic value of CDCP1 and to understand its function in RCC progression.

Grading Systems in Renal Cell Carcinoma

PURPOSE

We reviewed updated literature data concerning several issues of renal cell carcinoma grading systems.

MATERIALS AND METHODS

We performed a nonsystematic review of the literature. Data were identified by a MEDLINE search using a strategy including MeSH and free text protocols. From the MEDLINE search we collected 184 records.

RESULTS

Although the original study was published in 1982, the independent predictive value of nuclear grades was only revealed in 2000 by the team from University of California-Los Angeles. Subsequently further data from our group and the group at the Mayo Clinic reconfirmed those findings, although similar cancer specific survival probabilities were noted among different grades. The prognostic relevance of nuclear grade justified the inclusion of that variable in algorithms and nomograms predictive of cancer specific survival, such as those provided by University of California-Los Angeles, the Mayo Clinic and Memorial Sloan-Kettering Cancer Center. Despite the routine clinical use of nuclear grade, several drawbacks have affected grading systems, such as interobserver and intra-observer reproducibility, and variability of the cancer specific survival probabilities stratified by grade. Several studies showed that intra-observer and interobserver agreement with regard to grade are only moderate with up shifting in all series. That issue might be due to the heterogeneity of renal cell carcinoma as well as to the lack of consensus about the minimal size of high grade tumor to be considered significant. Moreover, recent data underscore the role of histological subtypes.

CONCLUSIONS

Grade is one of the most powerful prognostic factors in patients with renal cell carcinoma. The Fuhrman grading system is currently most widely used by pathologists in Europe and the United States. However, there is still a need for better standardization of nuclear criteria to improve interobserver reproducibility and a major consensus should be achieved by uropathologists.

Matrix metalloproteinase-9 polymorphisms and renal cell carcinoma in a Japanese population

Matrix metalloproteinase-9 (MMP-9) plays a pivotal role in cancer invasion and metastasis. Recently, experimental study has shown that MMP-9 is also implicated in early carcinogenesis. We hypothesized that MMP-9 polymorphisms influence the predisposition to develop renal cell carcinoma (RCC). To test the hypothesis, we determined MMP-9 C-1562T and R279Q genotypes in Japanese RCC cases (n=179) and controls (n=211). Furthermore, we investigated the relationship between MMP-9 polymorphisms and clinicopathological features. The distribution of C-1562T and R279Q genotypes was not significantly associated with the risk of RCC (odds ratio [OR]=1.14, 95% confidence interval [CI]=0.73-1.77 for -1562 CT/TT genotypes versus CC genotype; OR=1.29, 95% CI=0.86-1.93 for 279 RQ/QQ genotypes versus RR genotype). However, the distribution of R279Q genotypes was significantly associated with the histological grade (P<0.01). The present results suggest that MMP9 R279Q polymorphism has influence on the malignant potential of RCC.

Incidencia creciente en el carcinoma de células renales

OBJECTIVES

To analyze the change in the behavior of renal cell carcinoma for its presentation, treatment, histology and mortality during a 17 year period.

MATERIAL AND METHOD

Retrospective study on 212 patients diagnosed with renal cell carcinoma in our Department from the year 1988 up to 2004, analyzing the clinical and demographic data and comparing them to each other according to two periods: 1988-1996 and 1997-2004.

RESULTS

An increase has been appreciated in the incidence of renal tumors in the second period and in a same way an increase in the incidental diagnosis and in the practice of nephron sparing surgery. Clear cell type was the most frequent in both periods and tumoral size was higher in the first period than in second. TNM stage I was the most frequent, although in first period it was higher percentage of stage IV. Cause-specific mortality has increased in the last years.

CONCLUSION

An increase is appreciated in the incidence of renal cell tumors. Although the diagnosis is in earlier stages, a descent in the mortality has not been found.

A Review of Prognostic Pathologic Features and Algorithms for Patients Treated Surgically for Renal Cell Carcinoma

Accurate subtyping of RCC is critically important and should be considered in algorithms that are developed as prognostic tools for the patient and clinician. The TNM classification, already a powerful prognostic factor, will continue to evolve. The authors recommend that each component of the classification be assessed and reported during pathologic examination. This article also highlighted the importance of assigning a nuclear grade that is based on standardized and reproducible criteria that reflect the heterogeneity of nuclear and nucleolar features within RCC. Lastly, it is increasingly evident that coagulative tumor necrosis and sarcomatoid differentiation are compelling prognostic factors, on par with nuclear grade, and should be assessed routinely. To conclude, the complete list of pathologic features that are evaluated as part of the Mayo Clinic Nephrectomy Registry is presented. The features that are reported routinely in clinical practice also are indicated; this can serve as a guide for the reporting of results from the pathologic examination of RCC.

Original and reviewed nuclear grading according to the Fuhrman system

BACKGROUND

The objective of the current study was to evaluate the reproducibility of the Fuhrman nuclear grading system as well as its independent predictive value in a series of patients with conventional renal cell carcinoma (RCC).

METHODS

The authors selected 388 patients who had undergone surgical treatment for conventional RCC between 1986 and 2000. Pathology slides from the selected patients were reviewed by a single pathologist, who reassigned a Fuhrman nuclear grade and assessed the presence of tumor necrosis. The pathologist was blinded to both the original pathologic diagnosis and follow-up data. The kappa statistic was used to evaluate concordance between original and reviewed nuclear grades. The log-rank test was used for univariate analyses, and a Cox proportional hazards model was used for multivariate analyses.

RESULTS

The original Fuhrman nuclear grade was Grade 1 (G1) in 111 patients (28.6%), G2 in 141 patients (36.3%), G3 in 108 patients (27.8%), and G4 in 28 patients (7.3%). After pathology slide review, nuclear grades were reassigned as follows: G1 in 49 patients (12.6%), G2 in 138 patients (35.6%), G3 in 150 patients (38.7%), and G4 in 51 patients (13.1%). The grade of concordance was moderate (kappa=0.44; P <0.001). Univariate analyses identified three separate prognostic categories defined by nuclear grade (G1 and G2 vs. G3 vs. G4). Both the original and the reviewed Fuhrman nuclear grading systems were capable of independently predicting disease-specific survival in patients with conventional RCC.

CONCLUSIONS

The interobserver reproducibility of Fuhrman nuclear grading was moderate. The substantial overlap in survival curves for G1 and G2 tumors provided an opportunity to cluster those categories, and the resulting three-tiered nuclear grading system was an independent predictor of cause-specific survival in patients with conventional RCC. Other independent predictors of survival included pathologic stage and tumor necrosis status.

Comparison of standardized and nonstandardized nuclear grade of renal cell carcinoma to predict outcome among 2,042 patients

We compared the ability of original nuclear grades from surgical pathology reports and grades reviewed by a urologic pathologist to predict death due to renal cell carcinoma (RCC) for 2,042 patients treated with radical nephrectomy between January 1970 and December 1998. Reviewed grade I tumors had small, round nuclei with inconspicuous nucleoli visible at x400; grade 2 contained round to slightly irregular nuclei with mildly enlarged nucleoli visible at x200; grade 3 had round to irregular nuclei with prominent nucleoli visible at x100; grade 4 contained enlarged pleomorphic or giant cells. Predictive abilities were compared using R2 values from Cox proportional hazards models. There were 1,733 (84.87%) clear cell, 222 (10.87%) papillary, and 87 (4.26%) chromophobe tumors. Reviewed grades were more predictive of death due to RCC than original grades for clear cell (R2, 21% vs 16%), papillary (R2, 16% vs 13%), and chromophobe (R2, 39% vs 27%) RCC. Among patients with clear cell and papillary RCC, this difference was apparent even after adjusting for the 1997 TNM stage. Standardized nuclear grades were more predictive of death due to RCC than nonstandardized grades for all subtypes studied.