Prognostic significance of tumor grade for renal cell carcinoma

Grading of renal cell carcinoma

Grading of renal cell carcinoma (RCC) has been recognised as a prognostic factor for almost 100 years. Numerous grading systems have been proposed, initially focusing upon a constellation of cytological features and more recently on nuclear morphology. It has been recommended that grading of RCC should be based upon nucleolar prominence/eosinophilia for grades 1-3, while grade 4 requires nuclear anaplasia (including tumour giant cells, sarcomatoid differentiation and/or rhabdoid morphology). The grading system was adopted formally by the International Society of Urological Pathology (ISUP) and subsequently by the World Health Organisation (WHO), being designated the WHO/ISUP grading classification in the fourth edition of the WHO classification tumours of the urinary system and male genital organs (2016). This grading system has been validated for both clear cell and papillary RCC. Validation studies for chromophobe RCC failed to demonstrate a correlation between grade and outcome for both the superseded Fuhrman grading system and the WHO/ISUP grading classification, and it has been recommended that these tumours not be graded. The WHO/ISUP system has been incorporated into the structured reports of the International Cancer Collaboration on Cancer Reporting for both clear cell and papillary RCC. It is also noted that other types of RCC may be graded, but it must be emphasised in the report that this is for descriptive and diagnostic purposes, and not outcome prediction. More recent studies have shown the incorporation of the presence of tumour necrosis into RCC grading to improve outcome prediction, and this has been validated in several studies.

Advances and controversies in grading and staging of renal cell carcinoma

Despite the considerable progress made in our understanding of the pathogenesis, genetics, and pathology of renal cell carcinoma (RCC), difficulties remain relating to the prediction of clinical outcome for individual cases. Although there is evidence to show that high-grade tumors have a poorer prognosis when compared to those of low grade, debate remains regarding the predictive value of grading, especially for those tumors classified into the intermediate grades. Numerous composite morphologic and nuclear grading systems have been proposed for RCC and although that of the Fuhrman classification have achieved widespread usage, the validity of the grading criteria of this classification has been questioned. In addition, there are few studies that have attempted to validate the Fuhrman system for RCCs beyond that of the clear cell subtype. Recent studies have indicated that grading of papillary RCC should be based on nucleolar prominence alone and that the components of the Fuhrman grading classification do not provide prognostic information for chromophobe RCC. Independent of tumor grade, the prognostic importance of tumor stage for RCC is well recognized. The Union Internationale Contre le Cancer/American Joint Committee for Cancer Staging and End Results Reporting TNM staging system is now in its sixth edition (2002) and recent refinements have focused on defining size cut points that will identify apparently localized tumors that will develop recurrence and/or metastases despite attempted curative surgery. In parallel with these studies it has been shown that infiltration of the renal sinus is an important prognostic factor, being observed in almost all tumors >7 cm in diameter. Questions remain as to the appropriate stratification of regional extension of RCC, as defined in the T3 tumor-staging category. Recent modifications to this category have been suggested combining the level of infiltration of the venous outflow tract with the presence or absence of infiltration of the adrenal gland and/or perirenal fat. Similarly, the utility of classifying lymph node involvement by tumor is debated, although it is well recognized that lymph node infiltration is associated with a poor prognosis. Although the current TNM classification does provide useful prognostic information it would appear that further modifications are justified to enhance the predictive value of staging for RCC.

Percentage of high-grade carcinoma as a prognostic indicator in patients with renal cell carcinoma

BACKGROUND

The prognostic value of Fuhrman nuclear grade for patients with renal cell carcinoma has been well-characterized. However, to the authors' knowledge, the prognostic significance of the amount of high-grade renal cell carcinoma has not been previously analyzed.

METHODS

The authors identified 898 consecutive renal cell carcinoma cases treated with nephrectomy between 1989 and 2003. Histopathologic features that were captured based on re-review of all slides included histologic type, pathologic stage, conventional Fuhrman grade, and percentage of Fuhrman grade 3 and 4 carcinoma, as ascertained by visual inspection of histologic slides. The clinical endpoints were metastasis-free survival, cancer-specific survival, and overall survival.

RESULTS

Kaplan-Meier analysis demonstrated that both conventional Fuhrman grading and the percentage of Fuhrman grade 3 and 4 carcinoma were highly correlated with all 3 measures of patient survival (P < .0001). The creation of 3 categories of the percentage of Fuhrman grade 3 and 4 carcinoma (0%, 1-50%, and 51-100%) generated distinctly separate survival curves. On Cox proportional hazards multivariate analysis, TNM stage, tumor size, and the percentage of Fuhrman grade 3 and 4 carcinoma were all found to be significantly associated with all 3 types of patient survival (all P values <.05).

CONCLUSIONS

The determination of the percentage of renal cell carcinoma that is 0%, 1% to 50%, or 51% to 100% high Fuhrman grade 3 and 4 is a simple and powerful measurement of patient outcome after surgery that provides additional prognostic information beyond stage, tumor size, and conventional Fuhrman grade. This prognostic information could be useful in the stratification of patients into prognostic groups for the development of more individualized follow-upschedules and for enrollment into clinical trials.

Vitamin D receptor gene polymorphisms are associated with increased risk and progression of renal cell carcinoma in a Japanese population

AIM

Biological and epidemiologic data suggest that 1 alpha, 25 dihydroxyvitamin D(3) (1,25(OH)(2)D(3)) levels may influence development of renal cell carcinoma. The vitamin D receptor (VDR) is a crucial mediator for the cellular effects of 1,25(OH)(2)D(3) and additionally interacts with other cell signaling pathways that influence cancer progression. VDR gene polymorphisms may play an important role in risk of incidence for various malignant tumors. This study investigated whether VDR gene polymorphisms were associated with increased risk and prognosis of renal cell carcinoma (RCC) in a Japanese population.

METHODS

To analyze risk of RCC depending on VDR polymorphism, a case-control association study was performed. The VDR gene polymorphisms at three locations, BsmI, ApaI and TaqI, were genotyped in 135 RCC patients and 150 controls in a Japanese population. Logistic regression models were used to assess the genetic effects on prognosis.

RESULTS

Significant differences in the ApaI genotype were observed between RCC patients and controls (chi(2) = 6.90, P = 0.032). No statistical significant difference was found in the BsmI and TaqI polymorphisms. The frequency of the AA genotype in the ApaI polymorphism was significantly higher in the RCC patients than in the controls (odds ratio, 2.59; 95% confidence intervals, 1.21-5.55; P = 0.012). Multivariate regression analysis showed that the AA genotype was an independent prognostic factor for cause-specific survival (relative risk 3.3; P = 0.038).

CONCLUSION

The AA genotype at the ApaI site of the VDR gene may be a risk of incidence and poor prognosis factor for RCC in the Japanese population. Additional studies with a large sample size and investigation of the functional significance of the ApaI polymorphism in RCC cells are warranted.

Clinicopathological Relevance of Tumour Grading in Canine Osteosarcoma

Tumour grading assesses biological aggressiveness and is of prognostic significance in many malignancies. The clinicopathological features of 140 primary canine osteosarcomas and their metastases were analysed, and the interrelations between them and an established grading system and its constituent parameters (mitotic index, necrosis, pleomorphism) were examined. Of these tumours, 35% were grade III (high-grade), 37% grade II and 28% grade I. Primary tumours that had metastasized were of significantly higher grade than non-metastatic osteosarcomas. Osteosarcomas belonging to the osteoblastic minimally productive subtype, but not chondroblastic or telangiectatic subtypes, differed from fibroblastic osteosarcomas in being associated with a significantly higher number of high-grade cases. Dogs younger than 4 years of age had osteosarcomas with higher grade, score and mitotic index than did older animals. Appendicular differed from axial tumours in having a higher mitotic index; distal differed from proximal tumours in being of higher grade; cranial tumours differed from tumours in most other sites in being of lower grade and lower mitotic index. Rib osteosarcomas showed a particularly high degree of necrosis. The mitotic index varied widely between tumour locations. Pleomorphism did not have prognostic merit when examined separately, as most osteosarcomas were highly pleomorphic.

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.

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.

Clinicopathological factors predicting recurrence of N0M0 renal cell carcinoma: A case series analysis of one facility

BACKGROUND

Although many factors have been reported as predictors of the recurrence of renal cell carcinoma (RCC), none of the factors are consistent among different studies. In the study presented here, the potential clinicopathological predictors of the recurrence of N0M0 RCC were examined.

METHODS

A total of 201 patients who underwent nephrectomy for N0M0 RCC were examined to determine the pathological tumor stage (pT stage), pathological tumor grade of malignancy (tumor grade), symptoms, and tumor size.

RESULTS

RCC recurred in 29 patients (14.4%), 50% of whom developed new tumors within 24 months after nephrectomy. The disease-free 3- and 10-year survival rates declined as the pT stage and tumor grade increased: these rates were, respectively, 98.6% and 86.5% for pT1a; 93.7% and 87.9% for pT1b; 100% and 100% for pT2; 78.6% and 58.0% for pT3a; and 88.9% and 16.7% for pT3b. Significant differences in the recurrence rate were noted between pT3 and pT1 or pT2, as well as between grade 3 disease and grade 1 or grade 2 tumors. Multivariate analysis showed that a combination of the pT stage, grade, and presence of symptoms was useful for predicting the recurrence of RCC.

CONCLUSION

The present study showed that patients undergoing nephrectomy for N0M0 RCC should be followed-up carefully for 2 years postoperatively with special attention to high pT stage, high grade, and the development of symptoms.

Thymidine phosphorylase levels as a prognostic factor in renal cell carcinoma

OBJECTIVE

To investigate the relationship between thymidine phosphorylase (TP), a vascular growth factor, and established prognostic factors for renal cell carcinoma (RCC), e.g. histological grade or Tumour-Node-Metastasis (TNM) classification.

PATIENTS AND METHODS

TP levels were measured in RCC tissue (tumour TP) and in adjacent non-neoplastic kidney tissue (normal tissue TP), using a sandwich-type enzyme-linked immunosorbent assay. The 59 patients, diagnosed with organ-confined RCC before surgery and who had undergone radical nephrectomy, were divided into two groups according to their prognosis after surgery. Group 1 (nine patients) had a poor prognosis and group 2 (50) had no evidence of disease within a 65-month follow-up. The relationships among TP level, TNM classification, histological subtypes, V factor and prognosis, and of tumour TP to normal tissue TP levels were investigated. Multiple regression analysis was used to determine the importance of factors associated with increased TP levels.

RESULTS

Normal tissue TP levels correlated with histological grade (r = 0.31, P < 0.01); in patients with venous invasion or with a poor prognosis, the levels were significantly higher than in those without (P < 0.05 and < 0.001, respectively). The normal tissue TP levels were also significantly higher in the non-clear cell than in the clear cell subtype. Multiple regression analysis showed that the independent factor associated with elevated normal tissue TP levels was histological grade (R2 = 0.189, P < 0.01). There was no correlation between tumour TP and other factors.

CONCLUSION

Normal tissue TP levels in localized hypervascular RCC were associated with histological grade. These data suggest that normal tissue TP levels could be a prognostic factor.

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.

Clinical features of renal cell carcinoma less than 25 millimeters in diameter

BACKGROUND

We retrospectively investigated the clinicopathological features and prognosis of patients who underwent surgical treatment at our department for renal cell carcinoma (RCC) less than 25 mm in diameter.

METHODS

Of the 158 patients who underwent surgical treatment between April 1975 and April 1998, 16 (17 kidney, 10.1%) were included in this study. The study included 11 men and 5 women (ratio: 2.2). The age range was 35-76 years (average: age 53). The right kidney was involved in 9, left kidney in 6 and bilateral kidneys in 1 patient. The follow-up period was 26-157 months (mean: 86 months).

RESULTS

Thirteen tumors (81.2%) were incidental carcinomas. No patients had a tumor of rapid growing type. Radical nephrectomy was performed for 12 kidneys (70.6%), simple nephrectomy for 2 (11.8%) and partial nephrectomy for 3 (17.8%). Seven patients (43.7%) received interferon-alpha as postoperative adjuvant therapy. All tumors were pathologically classified as expansive type; 11 (64.8%) as clear cell carcinoma; 3 (17.6%) cyst-associated, and 3 (17.6%) papillary. Nine (52.9%) tumors were grade 1, and 8 (47.1%) were grade 2. Fourteen patients were pNo and V(-). The 5- and 10-year survival rates were excellent (100%).

CONCLUSION

The features of small RCCs less than 25 mm were as follows: many tumors were incidental to clear cell carcinomas; all tumors were low grade, low stage and expansive type; no tumors showed acute phase reactants; and few tumors were of the solid type. Thus, the prognosis seemed to be excellent.