Effect of papillary and chromophobe cell type on disease-free survival after nephrectomy for renal cell carcinoma

Cytogenetic profile predicts prognosis of patients with clear cell renal cell carcinoma

PURPOSE

The majority of cytogenetic studies in renal cell carcinoma (RCC) have been impaired by small sample size, retrospective character, and lack of a survival end point. We prospectively studied the prognostic impact of cytogenetic abnormalities on a larger cohort of patients having up to 108 months of follow-up.

PATIENTS AND METHODS

Tumors of 282 patients who underwent nephrectomy for clear cell RCC were cytogenetically analyzed. Results were correlated with pathological factors and disease-specific survival.

RESULTS

The most frequently observed cytogenetic abnormalities were loss of 3p (60%), gain of 5q (33%), loss of 14q (28%), trisomy 7 (26%), loss of 8p (20%), loss of 6q (17%), loss of 9p (16%), loss of 4p (13%), and loss of chromosome Y in men (55%). Tumors with loss of 3p presented at lower TNM stages. Loss of 4p, 9p, and 14q were all associated with higher TNM stages, higher grade, and greater tumor size. A deletion of 3p was associated with better prognosis (P = .03), while loss of 4p (P < .001), loss of 9p (P < .01), and loss of 14q (P < .01) were each associated with worse prognosis. Loss of the Y chromosome led to improved progression-free survival in metastatic patients (P = .02). In multivariate analysis, loss of 9p was retained as an independent prognostic factor.

CONCLUSION

This cytogenetic study serves as a proof of principal that genetic information, such as loss of chromosome 9, can be obtained from widely available technology, and can provide additional prognostic information to standard clinicopathologic variables.

VEGF neutralizing antibody increases the therapeutic efficacy of vinorelbine for renal cell carcinoma

Renal cell carcinoma (RCC) is currently one of the most treatment-resistant malignancies and affects approximately three in 10,000 people. The impact of this disease produces about 31,000 new cases in the United States per year; and 12,000 people in the United States alone die from RCC annually. Although several treatment strategies have been investigated for RCC, this cancer continues to be a therapeutic challenge. For this reason, the aim of our study is to develop a more effective combinational therapy to treat advanced RCC. We examined the effect of vinorelbine on the signalling pathways of two human renal cancer cell lines (A498 and 786-O) and also examined the in vivo effect of vinorelbine treatment alone and vinorelbine in combination with the anti-VEGF antibody 2C3 on A498 and 786-O tumour growth in nude mice. Tumour angiogenesis was measured by vWF staining, and apoptosis was determined by the TUNEL assay. We observed a significant tumour growth inhibition when using a combinational therapy of anti-VEGF antibody 2C3 and vinorelbine in both A498 and 786-O tumour-bearing mice. The results suggest a breakthrough treatment for advanced RCC.

Renal cell carcinoma: diagnosis, staging, and surveillance

OBJECTIVE

This educational review focuses on the staging and radiologic evaluation of renal cell carcinoma. It includes discussion of the epidemiology, pathology, and therapeutic options of renal cell carcinoma and the implications for radiologic follow-up.

CONCLUSION

The incidence of renal cell carcinoma has been increasing. Imaging plays a central role in its detection, staging, and treatment evaluation and follow-up.

MR imaging of renal masses: correlation with findings at surgery and pathologic analysis

Magnetic resonance (MR) imaging is useful in the characterization of renal masses. The MR imaging manifestations and pathologic diagnoses of 82 renal masses were reviewed and correlated. The MR imaging appearance of clear cell type renal cell carcinoma varies depending on the presence of cystic components, hemorrhage, and necrosis. Papillary renal cell carcinomas appear as well-encapsulated masses with homogeneous low signal intensity on T2-weighted images and homogeneous low-level enhancement after the intravenous administration of contrast material, or as cystic hemorrhagic masses with peripheral enhancing papillary projections. Transitional cell carcinoma may be seen as an irregular, enhancing filling defect in the pelvicaliceal system or ureter. Lymphomatous masses are usually hypointense relative to the renal cortex on T2-weighted images and enhance minimally on delayed gadolinium-enhanced images. Bulk fat is a distinguishing feature of angiomyolipoma. Oncocytoma has a variable and nonspecific appearance at MR imaging. MR imaging findings may allow the characterization of various renal masses and can provide valuable information for their clinical management.

Recent advances in the treatment of renal cell carcinoma and the role of targeted therapies

Immunotherapy confers a small but significant overall survival advantage in metastatic renal cell carcinoma (RCC) but only for the minority of patients, i.e. the 20% with good prognostic features. Recent developments in the molecular biology of renal cell carcinoma have identified multiple pathways associated with the development of this cancer. Several strategies have been investigated targeting these pathways, with significant clinical benefits shown in early studies. New agents including the small molecule targeted inhibitors sunitinib, sorafenib and temsirolimus, and the monoclonal antibody bevacizumab have shown anti-tumour activity in randomised clinical trials and have become the standard of care for most patients. Sunitinib and temsirolimus have shown significant improvements in progression-free survival (sunitinib) and overall survival (temsirolimus) in separate phase III studies in the first-line setting when compared with interferon-alpha. Sorafenib has demonstrated prolonged progression-free survival in a phase III study in comparison with placebo in the second-line setting. More recently two phase III studies have compared bevacizumab and interferon-alpha with interferon-alpha alone. Both studies showed a statistically significant improvement in progression-free survival for the combination arm. Additional studies are needed to optimise the use of these agents by identifying those patients who most benefit and elucidating the best way of delivering them, either in combination or as sequential single agents.

Comparison of type I and II papillary renal cell carcinoma (RCC) and clear cell RCC

OBJECTIVE

To compare the pathological features of clear cell renal cell carcinoma (ccRCC) with papillary RCC (pRCC) and further differentiate type I and II pRCC as independent prognosticators for survival.

PATIENTS AND METHODS

From September 1994 to February 2007 557 RCCs were treated and reviewed. All patients underwent radical nephrectomy or nephron-sparing surgery. We reviewed patient data and correlated RCC subtypes to tumour size, pathological stage, nuclear grade, and 5-year cancer-specific survival (CSS). pRCC was re-evaluated in to type I and II. The 2002 Tumour-Node-Metastasis and Fuhrman classifications were used.

RESULTS

In all, 391 (70%) patients had ccRCC, 96 (17%) had pRCC, 34 (6%) had chromophobe RCC, seven (1%) had ductus Bellini RCC and 29 (5%) had unclassified RCC. Upon re-evaluation 34 patients had type I pRCC and 62 had type II. The pRCCs were significantly smaller than the ccRCCs, at a mean (sd) of 4.5 (2.5) cm vs 5 (2.9) cm (P = 0.013), and multifocal (25% vs 12%, P = 0.001). Whereas patients with ccRCC had significantly more primary metastases (12% vs 3%, P = 0.014). The mean (sd) follow-up was 42.3 (41.4) months. The 5-year CSS for M0 patients was 84% for ccRCC and 90% for pRCC (P = 0.573). At multivariate analyses predictors for 5-year CSS were only tumour size (hazard ratio, HR 2.6, P < 0.001), pathological stage (HR 3.9, P < 0.001) and nuclear grade (HR 2.7, P < 0.001). The type I and II pRCCs had significantly different lymphovascular invasion (LVI) and 5-year CSS rates (94% vs 74%, P = 0.03).

CONCLUSIONS

The ccRCCs were significantly larger at diagnosis than the pRCCs. The histological subtype (pRCC vs ccRCC) had no impact on the 5-year CSS in multivariate analyses. The type I and II pRCCs had similar histopathological features except for a significant difference in LVI. However, the 5-year CSS was significantly different in type I and II pRCC.

Oncofetal protein IMP3: a novel molecular marker that predicts metastasis of papillary and chromophobe renal cell carcinomas

BACKGROUND

Whether an oncofetal protein, IMP3, can serve as a prognostic biomarker to predict metastasis for patients with localized papillary and chromophobe subtypes of renal cell carcinomas (RCCs) was investigated.

METHODS

The expression of IMP3 in 334 patients with primary papillary and chromophobe RCC from multiple medical centers was evaluated by immunohistochemistry. The 317 patients with localized papillary and chromophobe RCCs were further evaluated for outcome analyses.

RESULTS

IMP3 was significantly increased in a subset of localized papillary and chromophobe RCCs that subsequently metastasized. Patients with localized IMP3-positive tumors (n=33; 10%) were over 10 times more likely to metastasize (risk ratio [RR], 11.38; 95% confidence interval [CI], 5.40-23.96; P<.001) and were nearly twice as likely to die (RR, 1.91; 95% CI, 1.13-3.22; P=.016) compared with patients with localized IMP3 negative tumors. The 5-year metastasis-free and overall survival rates were 64% and 58% for patients with IMP3-positive localized papillary and chromophobe RCCs compared with 98% and 85% for patients with IMP3 negative tumors, respectively. In multivariable analysis adjusting for the TNM stage and nuclear grade, patients with IMP3-positive tumors were still over 10 times more likely to progress to distant metastasis (RR, 13.45; 95% CI, 6.00-30.14; P<.001) and were still nearly twice as likely die (RR, 1.95; 95% CI, 1.15-3.31; P=.013) compared with patients with IMP3-negative tumors.

CONCLUSIONS

IMP3 is an independent prognostic biomarker that can be used to identify a subgroup of patients with localized papillary and chromophobe RCC who are at high risk for developing distant metastasis.

Prognostic factors in a prospective series of papillary renal cell carcinoma

OBJECTIVE

To prospectively assess the clinical outcome of a series of papillary renal cell carcinomas (PRCCs) to identify possible prognostic clinical variables and tumour markers, as previous retrospective series of PRCC do not provide unanimous results on the prognostic utility of clinicopathological variables.

PATIENTS AND METHODS

Forty-six patients with PRCC (median follow-up 40 months) diagnosed in one institution from 1989 to 2002 were prospectively followed until May 2006. The pathology was reviewed, the PRCC subtyped (type 1 and 2) and immunohistochemistry assessed for MIB-1, vascular endothelial growth factor (VEGF), CD31 and c-met oncogenic protein, by a referee pathologist. Prognostic values were estimated by fitting a Cox model.

RESULTS

The 5-year survival rate was 49.5%; type 2 histology was predominant and was almost significant in the univariate analysis. Stage and MIB-1 were significant prognostic factors only in the univariate model, while the Cox model identified only the Fuhrman grade as an independent predictor of survival (hazard ratio 3.054; P = 0.007). MET expression, CD31 and VEGF had no prognostic utility.

CONCLUSION

These patients with PRCC followed prospectively fared worse than in previously reported series. The Fuhrman grade was the sole independent predictor of survival.

Analysis of clinicopathologic predictors of oncologic outcome provides insight into the natural history of surgically managed papillary renal cell carcinoma

BACKGROUND

To gain further insight into the natural history of papillary renal cell carcinoma (pRCC), the authors evaluated oncologic impact of important clinical and pathologic prognostic factors and performed survival analyses in a large group of contemporary patients surgically treated for pRCC.

METHODS

The institutional nephrectomy database was searched for patients who were managed with radical or partial nephrectomy for pRCC or clear cell RCC (cRCC) from 1994 to 2006.

RESULTS

A total of 2157 patients with pRCC (n=245) or cRCC (n=1912) met protocol inclusion criteria. Kaplan-Meier analyses revealed equivalent 5-year cancer-specific survival (CSS) in the nonmetastatic pRCC patient group and revealed significantly decreased CSS in pRCC patients with distant metastases compared with matched cRCC patient cohorts. Presence of venous tumor thrombus was associated with a significant decrease in CSS and was an independent prognostic feature in pRCC patient cohort but not in patients with cRCC (5-year CSS pRCC=35%; cRCC=66%; P= .012). Patients with pRCC were at a significantly increased risk of harboring metastatic lymph nodes compared with patients with cRCC (13% and 8.6%, respectively; P= .019); however, presence of lymph node metastases in patients with pRCC was associated with a relatively indolent disease course (5-year CSS pRCC=65%; cRCC=19%; P= .029).

CONCLUSIONS

The authors demonstrated significant differences in presentation, prognostic features, and patient outcomes among papillary and clear cell histologic subtypes of RCC. The authors' findings may potentially link unique molecular genetics that have been reported in pRCCs to its distinct clinical behavior.

Differences in organ system of distant metastasis by renal cell carcinoma subtype

PURPOSE

The majority of the published data regarding the rates of renal cell carcinoma metastasis to specific locations has examined renal cell carcinoma as a whole. We evaluated site of distant metastasis by renal cell carcinoma histological subtype.

MATERIALS AND METHODS

We studied 910 patients treated with radical nephrectomy for clear cell, papillary or chromophobe renal cell carcinoma at the Mayo Clinic between 1970 and 2000 who had distant metastasis at nephrectomy or who had metastasis during followup. The sites of metastases were compared by histological subtype using the chi-square and Fisher exact tests.

RESULTS

There were 853 (94%) patients with clear cell, 39 (4%) with papillary and 18 (2%) with chromophobe renal cell carcinoma. Median followup for the 65 patients who were still alive at last followup was 11.6 years. Patients with clear cell renal cell carcinoma were more likely to have metastasis to the lungs (53.6%) compared to those with papillary (33.3%) and chromophobe (33.3%) renal cell carcinoma (p = 0.012). Patients with chromophobe renal cell carcinoma were more likely to have metastasis to the liver compared to those with clear cell renal cell carcinoma (33.3% vs 9.7%, p = 0.007), but there was not a statistically significantly difference in the incidence of liver metastases between patients with chromophobe and papillary renal cell carcinoma (33.3% vs 18.0%, p = 0.308).

CONCLUSIONS

Site of distant metastasis varies significantly by renal cell carcinoma histological subtype. Patients with clear cell renal cell carcinoma are more likely to have metastasis to the lungs while patients with chromophobe renal cell carcinoma are more likely to experience liver metastasis.

Metastatic type-2 papillary renal cell carcinoma responded to interleukin-2 therapy: case report

This report documents a case of metastatic papillary renal cell carcinoma (PRCC) which successfully responded to interleukin-2 (IL-2) therapy. A 59-year-old male presented with a left renal mass measuring 3.0 cm in diameter and a right adrenal mass measuring 5.0 cm in diameter. He underwent a left partial nephrectomy and a right adrenalectomy. The histological findings revealed pT1bN1M1 type-2 PRCC and metastatic renal cell carcinoma in the right adrenal gland. The patient was given interferon-alpha (IFN-alpha) after the operation for 3 months. A CT scan revealed a metastatic nodule measuring 6.0 cm in diameter near the surface of the liver at 4 months after the operation. The patient was given interleukin-2 (IL-2), 7 x 10(5) units/day intravenously, for 3 days per week. A CT scan revealed this hepatic nodule to have decreased in size from 6.0 to 4.0 cm after 4 months of IL-2 therapy. However, a new metastatic nodule measuring 6.0 cm in diameter was found which came in contact with the spleen. Next, the patient was given an increased dose of IL-2 from 7 x 10(5) to 1.4 x 10(6) units/day intravenously, for 3 days per week. At 9 months of follow-up after the dose escalation, a CT scan revealed a dramatic decrease in the size of these two metastatic nodules to 1.5 and 0.5 cm, respectively. This is a very rare case in that it represents a type-2 PRCC which dramatically responded to low-dose IL-2 therapy.

Claudin-7 immunohistochemistry in renal tumors: a candidate marker for chromophobe renal cell carcinoma identified by gene expression profiling

CONTEXT

The differential diagnosis of eosinophilic renal tumors can be difficult by light microscopy. In particular, chromophobe renal cell carcinoma (RCC) is difficult to distinguish from oncocytoma. This differential diagnosis is important because chromophobe RCC is malignant, whereas oncocytoma is benign. Furthermore, chromophobe RCC has distinct malignant potential and prognosis compared with eosinophilic variants of other RCC subtypes. Immunohistochemistry is useful for distinguishing chromophobe RCC from other subtypes of renal carcinoma, but no expression marker reliably separates chromophobe RCC from oncocytoma.

OBJECTIVE

In a previous gene expression microarray analysis of renal tumor subtypes, we found the distal nephron markers claudin-7 and claudin-8 to be overexpressed in chromophobe RCC versus oncocytoma and other tumor subtypes. We have confirmed similar findings in independent microarray data and validated differential claudin-7 protein expression by immunohistochemistry.

DESIGN

Immunohistochemical analysis of claudin-7 in 36 chromophobe RCCs, 43 oncocytomas, 42 clear cell RCCs, and 29 papillary RCCs.

RESULTS

Membranous claudin-7 expression was detected in 67% chromophobe RCCs, compared with 0% clear cell RCCs, 28% papillary RCCs, and 26% oncocytomas (P < .001).

CONCLUSIONS

Based on microarray and immunohistochemical data, we propose claudin-7 to be a candidate expression marker for distinguishing chromophobe RCC from other renal tumor subtypes, including the morphologically similar oncocytoma. The clinical utility of claudin-7 should be validated in independent studies of renal tumors, possibly in combination with additional targets in a multiplex immunohistochemical panel.

Cytoreductive nephrectomy for metastatic renal cell carcinoma with nonclear cell histology

PURPOSE

To our knowledge the benefit of cytoreductive surgery for patients with metastatic renal cell carcinoma with nonclear cell histology is unknown. In this retrospective study we report our experience with cytoreductive nephrectomy for nonclear cell metastatic renal cell carcinoma at M. D. Anderson Cancer Center. We compared the outcomes with those in patients with clear cell metastatic renal cell carcinoma.

MATERIALS AND METHODS

From 1991 to 2006, 606 patients with metastatic renal cell carcinoma underwent cytoreductive nephrectomy and they formed the basis of this report. Of these patients 92 had nonclear cell metastatic renal cell carcinoma. The remaining 514 patients had clear cell metastatic renal cell carcinoma and they formed a comparative group. Multivariate Cox regression analysis was performed to evaluate the relationship between clinical variables and histology (clear cell vs nonclear cell) on disease specific survival.

RESULTS

Compared with patients with clear cell histology those with nonclear cell metastatic renal cell carcinoma were younger (p = 0.0001), and more likely to have nodal metastases (p <0.0001) and sarcomatoid features (23% vs 13%, p = 0.026). On multivariate analysis median disease specific survival in patients with nonclear cell histology was significantly worse than that in patients with clear cell metastatic renal cell carcinoma (9.7 vs 20.3 months, p = 0.0003) even after adjusting for T stage, grade, performance status, age and sarcomatoid features. Sarcomatoid features were a predictor of poor outcome in cases of clear and nonclear cell histology, although even in the absence of sarcomatoid features nonclear cell histology was associated with worse disease specific survival (p = 0.017). Interestingly although there was a significantly higher incidence of positive nodes in patients with nonclear histology (p <0.0001), this phenotype was not associated with a worse disease specific survival, as it was in those with clear cell histology (p = 0.0001). In fact, patients with node negative disease with nonclear cell histology had the worst prognosis overall in the entire group.

CONCLUSIONS

Patients with nonclear cell metastatic renal cell carcinoma were younger and had a higher incidence of nodal metastases, a higher incidence of sarcomatoid features and a worse prognosis than those with clear cell histology who underwent cytoreductive surgery.

Solid renal cortical tumors: differentiation with CT

PURPOSE

To retrospectively determine if solid renal cortical tumors can be differentiated on computed tomographic (CT) images on the basis of their morphologic features and enhancement patterns.

MATERIALS AND METHODS

Institutional review board approval was obtained and the informed consent requirement was waived for this HIPAA-compliant study. Between January 2004 and September 2005, 193 consecutive patients (age range, 19-95 years; 112 men, 81 women) with renal masses underwent total or partial nephrectomy and preoperative renal CT. Two radiologists retrospectively reviewed CT studies in an independent and blinded fashion. The pattern and degree of enhancement, lesion contour, presence of neovascularity, and calcifications were evaluated. Fisher exact tests, Pearson chi(2) tests, multivariate logistic regression, and Wilcoxon rank sum tests were performed.

RESULTS

Of the 198 renal tumors (median size, 3.4 cm; range, 1.1-20.0 cm) included in this study, 108 (55%) were clear cell renal cell carcinomas (RCCs); 30 (15%), papillary lesions; 24 (12%), chromophobe adenomas; 14 (7%), oncocytomas; six (3%), lipid-poor angiomyolipomas; and 16 (8%), other or unclassified renal tumors. Clear cell RCC most commonly manifested with a mixed enhancement pattern of both hypervascular soft-tissue components and low-attenuation areas that corresponded to necrotic or cystic changes (reader 1, 88% of clear cell tumors; reader 2, 79% of clear cell tumors). This pattern was highly predictive of clear cell RCC (odds ratio of 22 and 54 for readers 1 and 2, respectively, for comparison with homogeneous pattern), whereas the homogeneous and peripheral enhancing patterns were more predictive of less aggressive papillary and chromophobe lesions. Clear cell RCCs and oncocytomas tended to be hypervascular, chromophobe lesions and angiomyolipomas tended to enhance moderately, and papillary lesions were mostly hypovascular.

CONCLUSION

Certain imaging features and the degree of enhancement may be helpful in differentiating subtypes of renal cortical tumors.

Imaging in metastatic renal cell carcinoma

OBJECTIVE

Metastatic disease occurs in a significant percentage of patients with renal cell carcinoma. Recent advances in systemic therapies for metastatic renal cell carcinoma are likely to have a significant effect on the way patients with advanced disease are imaged. These new therapies have shown a significant increase in progression-free survival.

CONCLUSION

Imaging is likely to play an increasing role in the management, diagnosis, and monitoring of response to treatment of metastatic renal cell carcinoma.

Significance of Peritumoral Vascularity on CT in Evaluation of Renal Cortical Tumor

PURPOSE

To investigate whether the presence and degree of peritumoral vascularity may provide any diagnostic information regarding the histological subtypes of renal tumors.

MATERIALS AND METHODS

Between January 2004 and March 2006, 214 patients (age, 19-94 years; 120 men, 94 women) with renal masses underwent total or partial nephrectomy and preoperative renal protocol computed tomography. Two radiologists retrospectively reviewed the computed tomographic exams in an independent and blinded fashion. The radiologists evaluated the presence of peritumoral vascularity and measured the largest vessel caliber. Fisher exact tests, multivariate logistic regression, and Wilcoxon rank-sum tests were performed for statistical analysis.

RESULTS

Of 219 renal tumors (median size, 3.5 cm; range, 0.9-20.0 cm) included in this study, 112 (51%) were clear cell renal cell carcinoma, 34 (16%) were papillary, 32 (15%) were chromophobe, 17 (8%) were oncocytomas, 6 (3%) were lipid-poor angiomyolipomas, and 18 (8%) were other or unclassified renal tumors. The presence of peritumoral vascularity was significantly associated with tumor size within each subtype. For both readers, peritumoral vascularity was more frequently identified in clear cell carcinomas than in papillary renal carcinomas of similar size (P = 0.019 and 0.008, respectively). For one of the readers, chromophobe carcinomas were also significantly less frequently associated with peritumoral vascularity than clear cell carcinomas of similar size (P = 0.014).

CONCLUSIONS

Clear cell carcinomas demonstrate peritumoral vascularity significantly more frequently than other malignant renal tumors of similar size. The presence of peritumoral vascularity may provide additional diagnostic information and improve therapeutic planning in some cases.

Drug Insight: advances in renal cell carcinoma and the role of targeted therapies

In metastatic renal cell carcinoma (RCC) immunotherapy results in a small but important improvement in overall survival, but a need exists to develop more-effective systemic therapies. Recent developments in our understanding of the molecular biology of RCC have identified several pathways associated with the development of the disease. A number of strategies designed specifically to target these pathways have resulted. Initial studies have shown marked clinical benefits of so-called 'targeted therapies'. Sunitinib, sorafenib and axitinib are kinase inhibitors that inhibit the VEGF, platelet-derived growth factor and c-kit receptor tyrosine kinases. Bevacizumab is a monoclonal antibody that is directed against VEGF. Temsirolimus inhibits the mammalian target of rapamycin. These agents have all shown considerable activity with manageable toxicity in phase II and III studies in both previously treated and untreated patients. In phase III studies, sorafenib and bevacizumab have been associated with prolonged progression-free survival compared with placebo. Phase III data have shown improvements in progression-free and overall survival with sunitinib and temsirolimus, respectively, compared with interferon alfa. Additional studies are needed to determine the optimum utilization of these agents at the appropriate stage of disease and in the best combinations for maximal clinical benefit.

Second Prize: Frequency of Benign Renal Cortical Tumors and Histologic Subtypes Based on Size in a Contemporary Series: What to Tell our Patients

BACKGROUND AND PURPOSE

Historically, 85% to 90% of renal masses have been malignant, with the majority being renal-cell carcinoma. However, with the increasing frequency of incidentally discovered renal masses, only 70% to 85% of lesions are found to be malignant. Furthermore, the pathologic breakdown of these lesions on the basis of size is not well described. This study sought to determine the incidence of the various histologic subtypes of renal cortical tumors according to size in a contemporary series of surgically treated patients.

MATERIALS AND METHODS

Our prospectively collected database of all 482 patients who underwent partial or radical nephrectomy for a unilateral, unifocal, suspicious renal cortical tumor between January 2001 and October 2005 was reviewed. The frequency of benign and malignant lesions was determined according to size, as was the incidence of the various histologic subtypes.

RESULTS

Of the lesions, 228 were <or=4 cm, and 254 were >4 cm. Of all lesions <or=4 cm, 26.3% were benign, whereas only 8.3% of the lesions >4 cm were benign. For larger lesions, 10.9% of those between 4 and 7 cm and only 5.6% of those >7 cm were benign (P < 0.001). A significant difference between histologic subtypes according to size also was found (P = 0.01). Smaller lesions (<or=4 cm) that proved to be malignant were less likely than larger lesions to be of clear-cell histology (50.0% v 72.8%) and more likely to be papillary (15.8% v 9.4%).

CONCLUSIONS

This study examined the largest contemporary database evaluating the histologic type of renal lesions according to size. Approximately one fourth (26.3%) of lesions <or=4 cm and 16.8% of lesions overall were benign, percentages higher than those reported in older series. Importantly, there was a higher incidence of benign and papillary lesions and a lower incidence of clear-cell histology in smaller lesions. Given the differences in the biological behavior of the various histologic subtypes of these tumors, these data are important when counseling patients about the treated and untreated natural history of small renal masses.

[Synchronous metastases of the spermatic cord from papillary renal cell carcinoma]

Papillary renal cell carcinoma has been related with higher survival rate and lower metastatic cancer mortality rate than clear renal cell carcinoma. We present an aggressive case related to unusual features for this histological type, like a tumor size higher than ten cm, great perirrenal fat and suprarenal gland infiltration, tumoral thrombosis of the infrahepatic cava vein, retroperitoneal adenopatic tumoral infiltration, high nuclear grade and synchronous solitary distant organ metastases of the right spermatic cord, finding three previous cases in the literature with this last feature. Prognostic implication of the papillary renal cell carcinoma type is unclear in cases like this, so probably we need better molecular and cytogenetic studies to get a correct classification of this histological type.

Fuhrman Grading is not Appropriate for Chromophobe Renal Cell Carcinoma

This study was undertaken to assess the prognostic effectiveness of Fuhrman nuclear grading and the individual components of this grading system, in a series of chromophobe renal cell carcinomas. Eighty-seven cases of chromophobe renal cell carcinoma were investigated. There were 47 males and 40 females, 28 to 78 years of age. The carcinomas ranged from 25 to 180 mm in size and on TNM staging there were 38 stage I, 25 stage II, 22 stage III, and 2 stage IV tumors. Whole tumor Fuhrman grading was grade 1, 6 cases; grade 2, 72 cases; grade 3, 8 cases; and grade 4, 1 case, whereas focal (single high power field) grading was grade 1, 1 case; grade 2, 62 cases; grade 3, 21 cases; and grade 4, 3 cases. On assignment of nucleolar grading using Fuhrman criteria there were 37 grade 1, 44 grade 2, and 4 grade 3 tumors on whole tumor assessment and 3 grade 1, 63 grade 2, and 21 grade 3 tumors on assessment of the high power field showing the greatest degree of nuclear pleomorphism. Measurements of nuclear size showed nuclear area to range from 26.14 to 100.74 microm2, nuclear perimeter from 19.73 to 39.28 microm, and nuclear major axis from 6.49 to 13.21 microm, whereas the ranges of measures of nuclear shape were; shape factor 0.798 to 0.890, compactness 14.260 to 15.843, and feret diameter 5.694 to 11.242. Follow-up ranged from 1 to 150 months and 8 patients died of tumor-related causes 5 to 53 months from diagnosis. On log rank testing against survival, only patient age (P=0.016) and tumor maximum diameter (P=0.0055) were significant, whereas patient sex and TNM stage were not significant. Whole tumor and focal Fuhrman grading, as well as all measures of nucleolar prominence, nuclear size, and nuclear shape showed no significant association with outcome. It is concluded that neither Fuhrman grading, nor any of the components of the Fuhrman grading system, is useful as prognostic indicators for this tumor type.

Recent developments in renal cell cancer immunotherapy

Various immunotherapeutic approaches for the treatment of renal cell carcinoma (RCC) have been developed for > 90 years. Existing immunotherapeutic strategies against RCC include: systemic administration of cytokines; therapeutic vaccines based on tumor cells or dendritic cells; monoclonal antibodies; and adoptive immunotherapy (T cell transfer or allogeneic hematopoietic cell transplantation). However, the overall efficacy of immunotherapy for advanced RCC remains moderate. With the advent of molecularly targeted biological therapies that turned out to be significantly effective in the treatment of metastatic RCC, to many oncologists immunotherapy may seem to be moving into the periphery of RCC treatment strategies. However, for the last 2 years there has been significant progress made in immunotherapeutic approaches for the treatment of RCC. Immunotherapy still remains the only systemic therapeutic strategy that is believed to potentially cure RCC patients. The development of active and passive specific immunotherapeutic approaches, along with the possibility to 'switch off' particular immunosuppressive mechanisms (e.g., elimination of regulatory T cells, blockage of cytotoxic T lymphocyte antigen-4 signaling), have paved the way for future trials of new immunotherapies of RCC. However, the new studies will have to enroll optimally selected patients (nephrectomized, with non-massive metastases and good performance status) and will use tumor response criteria that are specifically optimized for clinical trials of immunotherapy.

Der kleine, zufällig entdeckte Nierentumor

Tumor size is a prognostic marker and correlates to survival after surgical therapy. Of 287 patients with small (<or=4 cm) renal tumors, 19.5% had a benign lesion and thus harmless. All others were renal cell cancers; 4.9% of tumors were detected because of metastases and consecutively treated. Tumors with a diameter <or=3 cm showed a tumor stage >or=pT3a in 10.9%, a high Fuhrman grade >or=3, multifocality in 8.5%, and metastases in 2.4%. Tumors with a diameter of 3.1-4 cm showed dramatically more aggressive parameters; 35.7% had stage >or=pT3a, 25.5% Fuhrman grade >or=G3, and 8.4% metastases (M+). However, evaluation of the tumor diameter on CT has an error of about +/-0.3 cm, which will lead to an even more pronounced error in volume determination. Therefore, determination of growth in follow-up imaging is unreliable. With the exception of the typical angiomyolipoma, determination of dignity for small solid kidney lesions is unreliable even with modern imaging. Only 17% of 80 benign lesions in our series were assessed as benign on preoperative CT. Thus, preoperative evaluation not only based on imaging seems to be valuable, especially in patients with higher surgical risk. Percutaneous renal mass biopsy has an accuracy of over 90% for detecting benign lesions and can influence therapeutic decisions, especially in patients with higher surgical risk.

Variable penetrance of a consensus classification scheme for renal cell carcinoma

OBJECTIVES

To evaluate the penetrance of the new pathologic standard of care, we characterized the temporal trends in histologic subtype-specific kidney cancer incidence rates. Molecular genetics have refined our understanding of kidney cancer, such that kidney cancer is now recognized as a family of tumors with distinct molecular and clinical characteristics. The histologic classification of kidney cancer has been revised to reflect this new paradigm.

METHODS

Using the Surveillance, Epidemiology, and End Results Program, we identified incident cases from 1983 to 2002. Tumor histologic types were assigned, using the International Classification of Disease-Oncology codes. The histologic-specific incidence rates were calculated and directly age-adjusted to the 2000 U.S. population.

RESULTS

The histologic type was available for 40,813 cases. Subsequent to the Heidelberg consensus conference, the rate of papillary histologic types rose appropriately from 0.02 in 1998 to 0.89 in 2002 per 100,000 U.S. population, and the incidence of granular cell histologic types remained relatively stable (0.22 to 0.14 cases per 100,000), despite its exclusion as a unique histologic subtype. Paradoxically, the incidence of chromophobe tumors decreased during this interval (0.03 to 0.003 cases per 100,000).

CONCLUSIONS

Following the publication of the Heidelberg classification scheme, we have described the differential changes in incidence rates for newly described histologic variants. Our results suggest incomplete penetration of these guidelines. The continued reporting of granular cell histologic types is particularly noteworthy, given that it is no longer recognized as a distinct histologic subtype. Proper categorization of the histologic subtype (eg, chromophobe, papillary, clear cell) is imperative, because it may confer useful information regarding the prognosis, response to adjuvant treatment, and eligibility for clinical trials.

Imaging of kidney cancer

Advances in molecular genetics have expanded the understanding of renal cell tumors. Now it is understood that renal cortical tumors are a family of neoplasms with distinct cytogenetics and molecular defects, unique histopathologic features, and different malignant potentials. Imaging contributes to clinical management of patients with renal tumors in providing diagnostic information for tumor detection, characterization, staging, treatment planning, and follow-up.

Treatment outcome for metastatic papillary renal cell carcinoma patients

BACKGROUND

Most clinical trial reports in metastatic renal cell carcinoma (RCC) do not distinguish between histologic subtypes, making it difficult to assess specific treatment efficacy. The current retrospective study sought to define clinical features and outcome data for metastatic papillary RCC.

METHODS

Clinical features, treatment outcome, and survival were evaluated in 38 patients with metastatic papillary RCC who underwent clinical evaluation at Memorial Sloan-Kettering Cancer Center (MSKCC) between 1985 and 2005. Twenty-three of 513 individuals were identified from a clinical trial database, 14 of 1895 from a surgery database, and 1 of 357 from a pathology database. A literature review of systemic therapy in metastatic papillary RCC was performed.

RESULTS

Among the 38 patients, 30 had been treated at MSKCC with various systemic therapies, including cytokines. Twelve therapies resulted in stable disease, 30 in initial progression of disease, and 1 in an unknown response. One patient had a partial response to sunitinib, a novel multitargeted tyrosine kinase inhibitor. The median overall survival time for the entire study group was 8 months (95% confidence interval, 5-12). A literature review on treatment of metastatic papillary RCC produced 4 reports, confirming a lack of efficacy for systemic therapy.

CONCLUSIONS

A resistance to systemic therapy characterizes patients with metastatic papillary RCC. Further understanding of the genetics and molecular biology and subtypes involved may provide the basis for more effective agents. Treatment with targeted therapies or other experimental agents is warranted.

Kinase inhibitors in the treatment of renal cell carcinoma

Immunotherapy confers a small but significant overall survival advantage in metastatic renal cell carcinoma (RCC) but a need exists to develop more effective systemic therapies. Angiogenesis has a key role in the pathophysiology of renal cell carcinoma and vascular endothelial growth factor (VEGF) is an important mediator of this process. Sunitinib, sorafenib and axitinib are new agents which belong to a class of drugs called kinase inhibitors and inhibit the VEGF, platelet-derived growth factor (PDGF) and c-KIT receptor tyrosine kinases. Temsirolimus inhibits the mammalian target of rapamycin (mTOR). All these agents have shown significant activity with manageable toxicity in metastatic RCC in phase 2 studies in patients generally pretreated with immunotherapy, whilst prolonged progression-free survival in a phase 3 study has been reported with sorafenib in comparison with placebo. Further phase 3 trials are recruiting and the combination of kinase inhibitors with other therapies is under investigation.

Novel kinase inhibitors in renal cell carcinoma: progressive development of static agents

The rapidly expanding knowledge regarding neoplastic diseases is providing a plethora of new targets for drug discovery and development as exemplified by recent data in renal cell carcinoma. The initial experience with molecularly "targeted" agents has demonstrated that development of the newer non-cytotoxic agents will provide unique challenges requiring modification of many traditional drug development concepts and methods. We discuss recently reported data from a few renal cell carcinoma trials with putative cytostatic agents and highlight issues that need to be addressed for efficient development of cytostatic agents during various phases of clinical development.

Prognostic role of the histologic subtypes of renal cell carcinoma after slide revision

OBJECTIVES

To evaluate concordance, using the kappa statistic, between tumour histotypes assigned at initial diagnosis and those after slide revision, and to assess the independent predictive value of reviewed tumour histotype.

MATERIALS AND METHODS

We analysed records of 491 patients who had undergone partial or radical nephrectomy for renal cell carcinoma (RCC) in our department from 1986 to 2000. Pathologic slides were reviewed by one uropathologist blinded to original diagnoses and follow-up data, who reassigned histologic subtype and nuclear grades.

RESULTS

Concordance between original and reviewed histotypes was substantial (kappa = 0.52). Data were affected by the year of initial diagnosis: Concordance was moderate (kappa = 0.43) in patients treated from 1986 to 1997 and substantial (kappa = 0.73) in those observed thereafter. The original histotype did not stratify the cancer-related outcome. According to the reviewed histotypes, the 5-year cancer-specific survival probabilities of conventional, papillary and chromophobe RCC patients were 81.3%, 90.1% and 100%, respectively (p = 0.009). Patients with conventional RCC showed significantly lower cancer-specific survival than those with papillary or chromophobe RCC, even in the cases with locally advanced (p = 0.04) or high-grade (p = 0.02) neoplasms. The reviewed histologic subtype was not an independent prediction of cancer-specific survival on multivariate analysis.

CONCLUSION

Concordance between histologic subtype assigned before 1997 and after slide revision was only moderate. In univariate analysis, reviewed tumour histotype stratified cancer-related outcome, but the data of multivariate analysis were strongly influenced by the prevalent number of conventional RCC.

Novel kinase inhibitors in renal cell carcinoma: progressive development of static agents

The rapidly expanding knowledge regarding neoplastic diseases is providing a plethora of new targets for drug discovery and development as exemplified by recent data in renal cell carcinoma. The initial experience with molecularly "targeted" agents has demonstrated that development of the newer non-cytotoxic agents will provide unique challenges requiring modification of many traditional drug development concepts and methods. We discuss recently reported data from a few renal cell carcinoma trials with putative cytostatic agents and highlight issues that need to be addressed for efficient development of cytostatic agents during various phases of clinical development.

Effect of incidental detection for survival of patients with renal cell carcinoma: results of population-based study of 701 patients

OBJECTIVES

To conduct a population-based study to evaluate the effect of incidental detection of renal cell carcinoma (RCC) on survival. Incidental detection of RCC has increased significantly in recent years because of widespread use of abdominal imaging. The patients with incidentally diagnosed RCC have better survival; however, because of possible "lead time" bias and stage migration, the real implications of incidental detection on survival have been a matter of debate.

METHODS

All living patients diagnosed with RCC in Iceland between 1971 and 2000 were included (n = 701). The histologic findings were verified, the stage (extent) of the disease was determined, and the incidence, mortality, and survival were evaluated.

RESULTS

The strongest predictors of mortality were stage and nuclear grade. After correcting for these factors in the multivariate analysis, incidental diagnosis, histologic subtype, and gender lost their significance as independent prognostic factors of death. However, the incidentally diagnosed tumors were 2.3 cm smaller on average and at a lower stage and grade than symptomatic tumors, with significantly better patient survival than those with symptomatic tumors on univariate analysis (76% versus 44% 5-year disease-specific survival). An increased incidence of RCC was only seen in men, but incidental detection increased threefold during the study period in both sexes, with significant improvement in survival for the whole group as a result.

CONCLUSIONS

The increased frequency of incidental detection has improved the survival of patients with RCC in Iceland. Incidental detection was not an independent prognostic factor of death, indicating that these tumors are of a similar biologic nature as symptomatic RCCs, only diagnosed earlier.

Elective nephron sparing surgery should become standard treatment for small unilateral renal cell carcinoma: Long-term survival data of 216 patients

OBJECTIVES

Our experiences with elective nephron-sparing surgery (NSS) for renal cell carcinoma (RCC) in a consecutive series of 216 patients are presented. Clinicopathological features and long-term oncological outcome is compared to patients treated with radical nephrectomy (RN).

METHODS

Between 1975 and 2002, NSS was performed in 488 patients; 311 of these patients had elective indications. Renal cell carcinoma was found in 241/311 patients (77.5%). Long-term follow up data could be obtained in 216/311 patients. Cancer-specific survival was estimated using the Kaplan-Meier method. Cox's regression analysis and log-rank tests were used to evaluate independent predictive values of different clinicopathological features. Survival data of the 216 patients after NSS surgery were compared to 369 patients with small RCC treated with RN.

RESULTS

After a mean follow up of 66 months (median 64 months) 29 (13.4%) of 216 patients treated with NSS had died, 4 of them (1.8%) tumour-related. Tumour recurrence was detected in 12 patients (5.6%). 204 patients (94.4%) were free of tumour at last follow-up. Cancer specific survival rates at 5 and 10 years for patients treated with NSS (RN) were 97.8% (95.5%) and 95.8% (84.4%).

CONCLUSIONS

Elective NSS surgery provides optimal long-term outcome in patients with small localized RCC. Compared to RN, renal parenchyma is preserved without any disadvantage in survival rates. Consequently elective NSS should be accepted as gold standard for small renal tumours.

Chromophobe renal cell carcinoma: comprehensive analysis of 104 cases from multicenter European database

OBJECTIVES

To analyze the clinical behavior of chromophobe renal cell carcinoma (CRCC), we retrospectively evaluated the data from six European centers. In 1985, CRCC was identified as a new RCC histologic subtype. Because of its low frequency, only few large CRCC series are available.

METHODS

We created a renal cancer database including 3228 patients who underwent surgery between 1986 and 2002 in six European centers. The relevant clinical and pathologic data were extracted from the clinical charts at each institution and collected into a unique database.

RESULTS

Of the 3228 patients, 104 (3.2%) affected by CRCC were identified. The mean age at diagnosis was 57.6 years (range 22 to 83). Of the 104 patients, 51 (49%) were men and 53 (51%) were women. The mean tumor size was 6.4 +/- 3.6 cm. An incidental diagnosis accounted for 61.5% of the cases. Radical nephrectomy was performed in 88 patients (85%). After a median follow-up of 38 months (mean 44, range 1 to 153), no local recurrence was observed. The 5-year overall survival rate for CRCC was 81%. Of the 104 patients, 5 (4.8%) and 9 (8.6%) died of unrelated causes and renal cancer, respectively.

CONCLUSIONS

Our series confirmed a favorable outcome for the CRCC subtype with little local aggressiveness and a low propensity for progression and death from cancer.

Histological Subtyping and Nuclear Grading of Renal Cell Carcinoma and Their Implications for Survival: A Retrospective Nation-Wide Study of 629 Patients

OBJECTS

The aim of this study was to evaluate the prognostic significance of the current WHO histological subtyping and Fuhrman nuclear grading on the survival of patients with renal cell carcinoma (RCC).

MATERIALS AND METHODS

A retrospective population-based study was carried out on all patients with a histopathologically confirmed diagnosis of RCC in Iceland between 1971 and 2000. Fuhrman grade, TNM stage, and survival were evaluated and multivariate analysis applied in order to determine prognostic factors.

RESULTS

Out of 629 patients (387 males, 242 females, mean age 64 years), 558 (88.7%) had clear cell, 53 (8.4%) papillary, and 13 (2.1%) chromophobe RCC. Patient demographics were comparable for the two major subtypes, but chromophobe RCCs were larger in size and were diagnosed at a younger age. Clear cell RCCs were more often of higher grades (G3+G4, 48.4%) and at advanced TNM stages (III+IV, 59.3%) than papillary RCCs (22.6% and 34% respectively, p<0.001). Linear regression analysis showed a strong correlation between grade, tumor size, and stage (p<0.001). Chromophobe RCCs had a better survival in univariate analysis than both papillary and clear cell RCCs (84.6% vs. 66.5% and 54.9% 5-year disease specific survival, p<0.001). However, in the multivariate analysis, only the patient's age, calendar year of diagnosis, TNM stage, and nuclear grade were independent prognostic factors of survival.

CONCLUSION

In this complete nation-wide series nuclear grading is important in predicting survival of patients with RCC. It is strongly related to both tumor size and stage, with stage being by far the strongest prognostic factor. Different histological subtypes confer different survival. However, in spite of the distinctive cytogenetic and molecular characteristics of the subtypes, the survival difference is to a large extent due to differences in grade and particularly stage.

Oncocytic renal neoplasms: diagnostic considerations

Advances in our understanding of renal neoplasia have resulted in recognition of numerous tumors that are composed predominantly of cells with abundant eosinophilic cytoplasm. This article discusses the features of renal oncocytoma (including oncocytosis), chromophobe renal cell carcinoma (RCC), and clear cell RCC; explores the relationship between renal oncocytoma and chromophobe RCC; briefly discusses other tumors with abundant eosinophilic cytoplasm; and emphasizes the differential diagnosis of such tumors.