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Purpose: While microvascular invasion is an accepted risk factor in various cancers, its prognostic role in renal cell carcinoma is still unclear. Therefore, a large multicenter study examining the experience of 5 international institutions was performed to evaluate the prognostic value of microvascular invasion in the occurrence of metastases and cancer specific survival. Materials and Methods: A total of 2,596 patients (475 with microvascular invasion and 2,121 without microvascular invasion) having up to 212 (median 22.4) months of followup were compared for differences in clinicopathological features, occurrence of metastases and cancer specific survival. Results: Patients with microvascular invasion presented with higher age (p = 0.001) and a worse Eastern Cooperative Oncology Group performance status (p <0.0001). Microvascular invasion was associated with larger tumor diameter (p <0.0001), higher Fuhrman grade (p <0.0001), more advanced pT stage (p <0.0001), and the presence of lymph node and distant metastases (p <0.0001). In particular, in nonmetastatic cases worse survival was associated with microvascular invasion (p <0.0001, HR 2.38). Univariate analysis demonstrated a strong correlation between microvascular invasion and cancer specific survival (p <0.0001). However, after controlling for gender, Eastern Cooperative Oncology Group performance status, Fuhrman grade and TNM stage statistical significance was lost. Of interest, low stage tumors with microvascular invasion were strongly correlated with the occurrence of metastases (p <0.0001). Conclusions: Microvascular invasion occurs in nearly 1 of 5 patients with renal cell carcinoma, is tightly correlated with adverse clinicopathological features and is an independent predictor of metastatic spread including in those presenting with low stage tumors. [ABSTRACT FROM AUTHOR]

Purpose: The prognostic usefulness of the Fuhrman nuclear grading system has been questioned for chromophobe renal cell carcinoma due to its frequent nuclear and nucleolar pleomorphism. Chromophobe tumor grade, a novel 3-tier tumor grading system based on geographic nuclear crowding and anaplasia, was recently reported to be superior to the Fuhrman system. We compared the 2 scoring systems in a large sporadic chromophobe renal cell carcinoma cohort to determine which grading scheme provides the most predictive assessment of clinical risk. Materials and Methods: We identified a total of 84 cases of sporadic chromophobe renal cell carcinoma in 82 patients from a total of 2,634 cases (3.2%) spanning 1989 to 2010. A subset of 11 tumors had secondary areas of sarcomatoid transformation. All cases were reviewed for Fuhrman nuclear grade and chromophobe tumor grade according to published parameters by an expert genitourinary pathologist blinded to clinicopathological information. Results: The distribution of Fuhrman nuclear grades 1 to 4 was 0%, 52.4%, 32.9% and 14.7% of cases, and the distribution of chromophobe tumor grades 1 to 3 was 48.8%, 36.5% and 14.7%, respectively. Metastasis developed in 20 patients (24.4%). Survival analysis revealed statistically significant differences in recurrence-free survival when adjusted for chromophobe tumor grade and Fuhrman nuclear grade. Chromophobe tumor grade showed a slightly higher AUC for recurrence-free survival and overall survival than the Fuhrman nuclear grading system. Neither chromophobe tumor grade nor Fuhrman nuclear grade was retained as an independent predictor of outcome in multivariate modeling when patients with sarcomatoid lesions were excluded. Conclusions: Chromophobe tumor grade effectively stratifies patients with chromophobe renal cell carcinoma across all grading levels. Since it does not rely on nuclear features, it avoids the hazard of overestimating the malignant potential of chromophobe renal cell carcinoma. Overall chromophobe tumor grade has higher predictive accuracy than the Fuhrman nuclear grading system. [ABSTRACT FROM AUTHOR]

Purpose: Papillary renal cell carcinoma is characterized histologically by tumors with cells arranged in a papillary pattern. Typically the cells have a chromophilic appearance but areas may show cells with clear cytoplasm, similar to those in clear cell renal cell carcinoma. Materials and Methods: We re-reviewed the histological slides of 148 patients with papillary renal cell carcinoma who underwent nephrectomy for the presence of clear cells. Results were correlated with other pathological features, immunohistochemical expression of 22 protein markers, cytogenetic analysis and overall survival. Results: Papillary renal cell carcinoma with clear cells was identified in 57 patients (39%). Clear cells were associated with higher T classification and grade, vascular invasion and type 2 papillary renal cell carcinoma. On immunohistochemistry these tumors revealed higher expression of epithelial vascular endothelial growth factor receptor-2 than papillary renal cell carcinoma without clear cells. All papillary renal cell carcinomas with clear cells expressed α-methylacyl-coenzyme A racemase and 76% expressed cytokeratin 7. Six of 8 tumors (75%) with chromosome 3p loss had clear cell features. The presence of clear cells was retained as an independent prognostic factor on multivariate analysis. In cases of papillary renal cell carcinoma with clear cells the loss of 3p material and absent cytokeratin 7 expression were associated with a worse outcome. Conclusions: Papillary renal cell carcinoma with clear cells is a novel entity with a unique clinical, immunohistochemical and cytogenetic phenotype. The presence of clear cells is associated with aggressive pathological characteristics and poorer prognosis. [ABSTRACT FROM AUTHOR]

Purpose: We developed and externally validated a prognostic nomogram specifically for papillary renal cell carcinoma. Materials and Methods: We retrospectively studied 435 patients who underwent radical or partial nephrectomy for papillary renal cell carcinoma at 3 institutions. Slides were reviewed by 1 uropathologist per institution. We constructed a nomogram predicting 5-year disease specific survival as a graphic representation of significant variables on multivariate Cox proportional hazards regression analysis using data on 258 patients from 2 of the 3 institutions. Nomogram discrimination and calibration were assessed by bootstrapping to obtain relatively unbiased estimates. External validation was done in 177 patients from a third institution. Results: At a median 50.8-month followup 77 papillary renal cell carcinoma related deaths had occurred. In the multivariate Cox proportional hazards model incidental detection, T classification, M classification, vascular invasion and tumor necrosis extent were retained as independent prognostic factors of disease specific survival and formed the basis of the nomogram. The nomogram predicted well with a 93.6% bootstrapped corrected concordance index and showed good calibration. External independent validation revealed 94.2% predictive accuracy. Conclusions: We developed a highly accurate tool specifically for papillary renal cell carcinoma using basic clinical and pathological information to predict disease specific survival. This tool should be helpful to identify papillary renal cell carcinoma with aggressive clinical behavior and may contribute to the ability to individualize postoperative surveillance and therapy. [Copyright &y& Elsevier]

Purpose: Recent evidence suggests that nucleolar grade but not Fuhrman grade is applicable to papillary renal cell carcinoma. We tested this hypothesis in an independent large series from a single institution. Materials and Methods: One dedicated uropathologist regraded 158 cases of papillary renal cell carcinoma by nucleolar and Fuhrman grades. The prognostic value and predictive accuracy of these grading systems to predict disease specific survival were analyzed by Cox proportional hazards models and the concordance index. Results: There were 39 papillary renal cell carcinoma related deaths (25%) at a mean followup of 50 months. On univariate analysis nucleolar grade predicted disease specific survival with a concordance index of 67.8% but the survival difference between grades 1 and 2 did not attain statistical significance (p = 0.1441). Fuhrman grade predicted disease specific survival significantly better (concordance index 74.7%, p <0.001). Comparison of survival estimates between the grades revealed statistical significance across each grade category (each p <0.05). Fuhrman but not nucleolar grade was retained as an independent prognostic factor on multivariate analysis (p = 0.027 and 0.128, respectively). Conclusions: Each grading system performs well but the predictive accuracy of Fuhrman grade is statistically superior to that of nucleolar grade and only Fuhrman grade provides independent prognostic information on patients with papillary renal cell carcinoma. Thus, Fuhrman grade should be the standard grading system for papillary renal cell carcinoma. [Copyright &y& Elsevier]

Purpose: We assessed CA9 single nucleotide polymorphisms and mutations, and their association with CAIX protein expression, overall survival and response to interleukin-2 in white patients with metastatic clear cell renal cell carcinoma. Materials Methods: Genomic DNA was extracted from frozen tumor samples of 54 metastatic clear cell renal cell carcinomas. The CA9 gene exons and flanking regions were amplified by polymerase chain reaction and sequenced. The monoclonal antibody M75 was used to evaluate CAIX protein expression in the primary tumor by immunohistochemistry. Results: CA9 reference single nucleotide polymorphisms rs2071676, rs12553173, rs3829078 and rs1048638 were found in 59%, 15%, 11% and 33% of patients, respectively. The deletion c.376del393 was observed in 2 patients. CAIX expression was greater than 85% in 65% of patients. No single nucleotide polymorphisms were significantly associated with CAIX expression. Patients with the C allele variant of rs12553173 had improved median survival (27.3 vs 13.6 months, p = 0.0431) and a greater likelihood of an interleukin-2 response (57% vs 22%, p = 0.081) Likewise high CAIX expression was associated with longer median survival (25.5 vs 8.5 months, p <0.0001) and a greater interleukin-2 response rate (37% vs 8%, p = 0.070). In a multivariate Cox model the C allele variant of CA9 single nucleotide polymorphism rs12553173 and CAIX expression were retained as independent prognostic factors. Conclusions: CA9 single nucleotide polymorphisms are common in patients with metastatic clear cell renal cell carcinoma. The synonymous C allele variant of rs12553173 may be associated with improved overall survival and a greater likelihood of a response to interleukin-2. CA9 rs12553173 and CAIX are independent prognostic factors of overall survival and complementary for predicting the prognosis of metastatic clear cell renal cell carcinoma. [Copyright &y& Elsevier]

Purpose: The presence of necrosis has been proposed as an adverse prognostic factor in clear cell renal cell carcinoma. However, classification based on a presence/absence basis ignores its heterogeneity, which may be associated with other important pathological factors and prognosis. We performed the first prospective study of necrosis in clear cell renal cell carcinoma to our knowledge and tested the traditional presence/absence classification vs an alternative extent based classification. Materials and Methods: We studied the presence and extent of tumor necrosis, pathological features and cancer specific survival of 343 consecutive patients. Results: Tumor necrosis was present in 227 tumors (66%) and was associated with more advanced tumors. However, the predictive accuracy for cancer specific survival was low (64.6%) and the presence of necrosis was not retained as an independent prognostic factor on multivariate analysis (p = 0.299). There was significant heterogeneity among tumors with necrosis. Increasing extent of necrosis was associated with poorer performance status, higher T, N, M stages and grades, vascular invasion and sarcomatoid features. Extent based classification predicted cancer specific survival better than presence alone (74.5% vs 64.6%) and was retained as an independent prognostic factor on multivariate analysis (p = 0.029). For clinical use a cutoff of 20% was identified for further prognostic subclassification of tumors with necrosis (c-index 71.7%). Conclusions: Tumor necrosis is an adverse prognostic factor in clear cell renal cell carcinoma but prospective evaluation of necrosis on a presence/absence basis shows that it does not provide independent prognostic information. The predictive accuracy of an extent based classification is superior and is retained as an independent prognostic factor. We recommend the scoring of necrosis according to its extent with further subclassification based on a 20% cutoff. [Copyright &y& Elsevier]

Purpose: We characterized the clinicopathological features and the prognosis of small solid renal tumors defined as tumors 4 cm or smaller. Materials and Methods: We identified 1,208 patients who were treated with nephrectomy at 5 international academic centers for small solid renal tumors. Clinicopathological parameters and outcome data were collected for each patient and analyzed. Results: Of the tumors 88% were renal cell carcinoma and 12% were benign. Of those with renal cell carcinoma 995 (93%) were localized (N0M0) and 72 (7%) presented with metastatic disease. Tumor size did not predict synchronous metastatic disease. The incidence of metastatic disease in the tumor size ranges 0.1 to 1.0, 1.1 to 2.0, 2.1 to 3.0 and 3.1 to 4.0 cm was 7%, 6%, 5% and 8%, respectively (p = 0.322). Survival rates were excellent. The majority of patients who died of renal cell carcinoma (54%) presented with synchronous metastatic disease, but 3% of patients with localized disease also died of renal cell carcinoma. In patients with localized disease there was a 7% chance of recurrence post nephrectomy at 5 years. Progression-free survival (28 months) was better than for patients with metastatic disease having a primary tumor greater than 4 cm (8 months). Tumor size was not retained as an independent prognostic factor of survival in multivariate analyses. The University of California Integrated Staging System and the Karakiewicz nomogram were the best predictors of cancer specific survival for all renal cell carcinoma stages (c-index 0.87). Conclusions: More than 85% of small solid renal tumors are renal cell carcinoma. The majority of localized small renal tumors can be cured with existing surgical approaches. However, there is a small but not insignificant risk of synchronous and metachronous metastatic disease and cancer associated death. Patients considering experimental therapies such as ablation and surveillance should be aware of this. Tumor size alone is not sufficient to distinguish renal cell carcinoma with benign behavior from aggressive small renal cell carcinoma. Survival of patients with small metastatic renal cell carcinoma is better then expected. The biology of these unique tumors should be further studied. [Copyright &y& Elsevier]

Purpose: Through its binding with interferon inducible angiostatic chemokines the chemokine receptor CXCR3 has an important role in regulating tumor mediating immunity, angiogenesis and metastatic spread. To evaluate its role in the biology of clear cell renal cell carcinoma we performed a tissue microarray based study. Materials and Methods: The tissue microarray comprised 154 patients who underwent nephrectomy for localized (N0M0) clear cell renal cell carcinoma at UCLA from 1989 to 2000. Immunohistochemical staining was evaluated by 2 anatomical pathologists who were blinded to outcome. The end point of this study was disease-free survival. Median followup was 5.9 years. Results: A total of 96% of the tumor specimens stained positive for CXCR3. The mean percent of cells staining positive was 68% (range 0 to 100%). CXCR3 expression was not associated with other common clinicopathological features, such as Eastern Cooperative Oncology Group performance status, T stage, Fuhrman grade, vascular invasion or sarcomatoid features. Patients with low CXCR3 expression (less than 30%) had a significantly worse prognosis than patients with high CXCR3 expression with a 5-year disease-free survival rate of 57% vs 82% (p = 0.009). Multivariate Cox regression analysis retained T stage, Eastern Cooperative Oncology Group performance status, sarcomatoid features and CXCR3 as independent prognostic factors. Conclusions: CXCR3 is a novel molecular marker in patients with clear cell renal cell carcinoma. Its higher expression is an independent predictor of improved disease-free survival following nephrectomy for localized disease. Since CXCR3 is not associated with other clinicopathological prognostic factors, it may represent an ideal complementary molecular marker for identifying patients who are at higher risk for recurrence after nephrectomy. [Copyright &y& Elsevier]

Purpose: We identified prognostic factors for renal cell carcinoma with tumor thrombus extension and assessed whether the current T3 classification could be improved. Materials and Methods: We studied clinicopathological parameters in 321 consecutive patients who were surgically treated for renal cell carcinoma with tumor thrombus extension. Disease specific survival was evaluated with univariate and multivariate analysis. Harrell’s C-index was used to assess the prognostic accuracy of prognostic models. Results: Tumor thrombus extended into the renal vein in 166 patients, the inferior vena cava in 137 and the atrium in 18. Metastatic renal cell carcinoma was found in 198 patients (62%). The thrombus level had no impact on clinicopathological parameters or survival but perioperative morbidity and mortality increased with cranial extension of the thrombus. Mean followup was 49 months. Five and 10-year disease specific survival rates were 36% and 24%, respectively. On multivariate analysis Eastern Cooperative Oncology Group performance status, lymph node and distant metastases, sarcomatoid features and perinephric fat invasion were independent prognostic factors. Weight loss, anemia, collecting system invasion, incomplete surgical resection, nuclear grade and T classification were also significant prognosticators on univariate analysis. For patients with advanced disease the number of metastatic sites and the disease-free interval further predicted prognosis. The overall immunotherapy response rate was 19%, which decreased with cranial extension of the thrombus. Redefinition of the T3 classification with the incorporation of fat invasion improved prognostic accuracy, as shown by an increase in the C-index. Conclusions: Eastern Cooperative Oncology Group performance status, metastatic status, sarcomatoid features and concomitant perinephric fat invasion are the most powerful prognostic factors of survival in renal cell carcinoma with tumor thrombus extension. Our data indicate that a redefinition of the current T3 classification may improve its predictive accuracy. We propose that T3 renal cell carcinoma with fat invasion or thrombus extension alone should be classified as T3a, while that with thrombus extension plus fat invasion should be classified as T3b. [Copyright &y& Elsevier]

Purpose: The current tumor classification for renal cell carcinoma classifies pT2 tumors as larger than 7 cm in greatest dimension and limited to the kidney. We examined the current pT2 tumor classification of renal cell carcinoma and determined whether a tumor size cutoff exists that would improve prognostic accuracy. Materials and Methods: We studied 706 patients with pT2 renal cell carcinoma treated with surgical extirpation at 9 international academic centers. Data collected from each patient included age at diagnosis, gender, 2002 TNM (tumor, node, metastasis) stage, tumor size, nuclear grade, performance status, histological subtype and disease specific survival. Disease specific survival was evaluated with univariate and multivariate analysis. Results: Median followup was 52 months. Univariate Cox regression analysis showed a significant association of tumor size with disease specific survival (HR 1.11, p <0.001). An ideal tumor size cutoff of 11 cm was identified, which led to the stratification of 2 groups with respect to disease specific survival (p <0.0001) with 5 and 10-year survival rates of 73% and 65% for pT2 11 cm or less, and 57% and 49% for pT2 larger than 11 cm, respectively. The incidence of metastases was significantly greater in the larger than 11 cm group, while Eastern Cooperative Oncology Group performance status, Fuhrman grade and histological subtype were similar. Multivariate Cox regression analysis retained tumor size as an independent prognostic factor and as the strongest prognostic factor for patients with pT2N0M0 disease. Conclusions: Our data suggest that the current pT2 classification can be improved by subclassification into pT2a and pT2b based on a tumor size cutoff of 11 cm. Patients in the proposed pT2bN0M0 group are at higher risk for death from renal cell carcinoma and should be considered for adjuvant therapies. External validation is warranted before suggesting change to the TNM classification. [Copyright &y& Elsevier]

Purpose: We evaluated the prognosis, risk factors and relevance of the primary-free interval in a large cohort with metachronous bilateral renal cell carcinoma. Materials and Methods: We studied 120 patients with metachronous, bilateral renal cell carcinoma who were treated at 12 international academic centers. Logistic regression was performed to evaluate risk factors for contralateral metachronous renal cell carcinoma during followup. Disease specific survival was evaluated with univariate and multivariate analysis. Results: Median age at diagnosis of the first and second renal cell carcinomas was 54 and 62 years, respectively. The most common histological subtype was bilateral clear cell renal cell carcinoma (89% of cases). Familial renal cell carcinoma was found in 14% of patients, von Hippel-Lindau disease was found in 4% and nonfamilial renal cell carcinoma was found in 81%. The 15-year disease specific survival rates for the first and second renal cell carcinomas were 66% and 44%, respectively. Logistic regression revealed von Hippel-Lindau disease, a family history of renal cell carcinoma, multifocal first renal cell carcinoma and young patient age as independent risk factors for contralateral renal cell carcinoma after surgery for unilateral renal cell carcinoma. A longer primary-free interval was associated with a better prognosis. When calculating disease specific survival from the diagnosis of the first renal cell carcinoma, the primary-free interval was an independent prognostic factor. Conclusions: Long-term survival rates of metachronous, bilateral renal cell carcinoma are moderate. von Hippel-Lindau disease, a family history of renal cell carcinoma, multifocal first renal cell carcinoma and young patient age are independent risk factors for contralateral renal cell carcinoma. These risk factors support close and extended abdominal surveillance following nephrectomy for unilateral renal cell carcinoma. Patients with a longer primary-free interval have a more favorable prognosis. [Copyright &y& Elsevier]