Principles of nephrectomy for malignant disease

Identification of mortality-risk-related missense variant for renal clear cell carcinoma using deep learning

Introduction:

Kidney renal clear cell carcinoma (KIRCC) is a highly heterogeneous and lethal cancer that can arise in patients with renal disease. DeepSurv combines a deep feed-forward neural network with a Cox proportional hazards function and could provide optimized survival results compared with convenient survival analysis.

Methods:

This study used an improved DeepSurv algorithm to identify the candidate genes to be targeted for treatment on the basis of the overall mortality status of KIRCC subjects. All the somatic mutation missense variants of KIRCC subjects were abstracted from TCGA-KIRC database.

Results:

The improved DeepSurv model (95.1%) achieved greater balanced accuracy compared with the DeepSurv model (75%), and identified 610 high-risk variants associated with overall mortality. The results of gene differential expression analysis also indicated nine KIRCC mortality-risk-related pathways, namely the tRNA charging pathway, the D-myo-inositol-5-phosphate metabolism pathway, the DNA double-strand break repair by nonhomologous end-joining pathway, the superpathway of inositol phosphate compounds, the 3-phosphoinositide degradation pathway, the production of nitric oxide and reactive oxygen species in macrophages pathway, the synaptic long-term depression pathway, the sperm motility pathway, and the role of JAK2 in hormone-like cytokine signaling pathway. The biological findings in this study indicate the KIRCC mortality-risk-related pathways were more likely to be associated with cancer cell growth, cancer cell differentiation, and immune response inhibition.

Conclusion:

The results proved that the improved DeepSurv model effectively classified mortality-related high-risk variants and identified the candidate genes. In the context of KIRCC overall mortality, the proposed model effectively recognized mortality-related high-risk variants for KIRCC.

Modulator-Dependent RBPs Changes Alternative Splicing Outcomes in Kidney Cancer

Alternative splicing alterations can contribute to human disease. The ability of an RNA-binding protein to regulate alternative splicing outcomes can be modulated by a variety of genetic and epigenetic mechanisms. In this study, we use a computational framework to investigate the roles of certain genes, termed modulators, on changing RBPs' effect on splicing regulation. A total of 1,040,254 modulator-mediated RBP-splicing interactions were identified, including 137 RBPs, 4,309 splicing events and 2,905 modulator candidates from TCGA-KIRC RNA sequencing data. Modulators function categories were defined according to the correlation changes between RBPs expression and their targets splicing outcomes. QKI, as one of the RBPs influencing the most splicing events, attracted our attention in this study: 2,014 changing triplets were identified, including 1,101 modulators and 187 splicing events. Pathway enrichment analysis showed that QKI splicing targets were enriched in tight junction pathway, endocytosis and MAPK signaling pathways, all of which are highly associated with cancer development and progression. This is the first instance of a comprehensive study on how alternative splicing outcomes changes are associated with different expression level of certain proteins, even though they were regulated by the same RBP. Our work may provide a novel view on understanding alternative splicing mechanisms in kidney cancer.

Indications, complications, and outcomes following surgical management of locally advanced and metastatic renal cell carcinoma

INTRODUCTION

Surgery may set the basis for a potential cure or would provide the best achievable quality of life in locally advanced or metastatic renal cell carcinoma (mRCC). However, survival extension with this approach would be scarce and not exempt from adverse events, thus preventing its recommendation in an already frail patient. An evidence based analysis on the role of surgery in each of the possible clinical scenarios involved under this heading may provide a clear picture on this issue and would be of value in the decision making process. Areas covered: Current literature was queried in PubMed/Medline in a systematic fashion. Manuscripts included were selected according to the quality of the data provided. A narrative review strategy was adopted to summarize the evidence acquired. Expert commentary: A surgery-based multimodal treatment approach should be strongly considered after adequate counseling in locally advanced and mRCC, since it may provide for additional benefits in terms of survival. However, a critical reevaluation of its adequacy, optimal timing, and selection of ideal candidates is currently ongoing.

Identification of prognostic genes in kidney renal clear cell carcinoma by RNA‑seq data analysis

The present study aimed to analyze RNA-seq data of kidney renal clear cell carcinoma (KIRC) to identify prognostic genes. RNA‑seq data were downloaded from The Cancer Genome Atlas. Feature genes with a coefficient of variation (CV) >0.5 were selected using the genefilter package in R. Gene co‑expression networks were constructed with the WGCNA package. Cox regression analysis was performed using the survive package. Furthermore, a functional enrichment analysis was conducted using Database for Annotation, Visualization and Integrated Discovery tools. A total of 533 KIRC samples were collected, from which 6,758 feature genes with a CV >0.5 were obtained for further analysis. The KIRC samples were divided into two sets: The training set (n=319 samples) and the validation set (n=214 samples). Subsequently, gene co‑expression networks were constructed for the two sets. A total of 12 modules were identified, and the green module was significantly associated with survival time. Genes from the green module were revealed to be implicated in the cell cycle and p53 signaling pathway. In addition, a total of 11 hub genes were revealed, and 10 of them (CCNA2, CDC20, CDCA8, GTSE1, KIF23, KIF2C, KIF4A, MELK, TOP2A and TPX2) were validated as possessing prognostic value, as determined by conducting a survival analysis on another gene expression dataset. In conclusion, a total of 10 prognostic genes were identified in KIRC. These findings may help to advance the understanding of this disease, and may also provide potential biomarkers for therapeutic development.

Identification of genes and pathways involved in kidney renal clear cell carcinoma

BACKGROUND

Kidney Renal Clear Cell Carcinoma (KIRC) is one of fatal genitourinary diseases and accounts for most malignant kidney tumours. KIRC has been shown resistance to radiotherapy and chemotherapy. Like many types of cancers, there is no curative treatment for metastatic KIRC. Using advanced sequencing technologies, The Cancer Genome Atlas (TCGA) project of NIH/NCI-NHGRI has produced large-scale sequencing data, which provide unprecedented opportunities to reveal new molecular mechanisms of cancer. We combined differentially expressed genes, pathways and network analyses to gain new insights into the underlying molecular mechanisms of the disease development.

RESULTS

Followed by the experimental design for obtaining significant genes and pathways, comprehensive analysis of 537 KIRC patients' sequencing data provided by TCGA was performed. Differentially expressed genes were obtained from the RNA-Seq data. Pathway and network analyses were performed. We identified 186 differentially expressed genes with significant p-value and large fold changes (P < 0.01, |log(FC)| > 5). The study not only confirmed a number of identified differentially expressed genes in literature reports, but also provided new findings. We performed hierarchical clustering analysis utilizing the whole genome-wide gene expressions and differentially expressed genes that were identified in this study. We revealed distinct groups of differentially expressed genes that can aid to the identification of subtypes of the cancer. The hierarchical clustering analysis based on gene expression profile and differentially expressed genes suggested four subtypes of the cancer. We found enriched distinct Gene Ontology (GO) terms associated with these groups of genes. Based on these findings, we built a support vector machine based supervised-learning classifier to predict unknown samples, and the classifier achieved high accuracy and robust classification results. In addition, we identified a number of pathways (P < 0.04) that were significantly influenced by the disease. We found that some of the identified pathways have been implicated in cancers from literatures, while others have not been reported in the cancer before. The network analysis leads to the identification of significantly disrupted pathways and associated genes involved in the disease development. Furthermore, this study can provide a viable alternative in identifying effective drug targets.

CONCLUSIONS

Our study identified a set of differentially expressed genes and pathways in kidney renal clear cell carcinoma, and represents a comprehensive computational approach to analysis large-scale next-generation sequencing data. The pathway and network analyses suggested that information from distinctly expressed genes can be utilized in the identification of aberrant upstream regulators. Identification of distinctly expressed genes and altered pathways are important in effective biomarker identification for early cancer diagnosis and treatment planning. Combining differentially expressed genes with pathway and network analyses using intelligent computational approaches provide an unprecedented opportunity to identify upstream disease causal genes and effective drug targets.

Neoadjuvant targeted therapy in a primary metastasized renal cell cancer patient leads to down-staging of inferior vena cava thrombus (IVC) enabling a cardiopulmonary bypass-free tumor nephrectomy: a case report

BACKGROUND

We report on a 62-year-old gentleman presenting at our urological department with an advanced renal cell cancer of the right kidney (10 cm in diameter), with an extensive caval vein thrombus (level IV) and bilateral pulmonary metastases. Another suspicious lesion at the left hemithorax was radiologically described.

METHOD

A presurgical, neoadjuvant systemic therapy with sunitinib, a tyrosine kinase inhibitor, was initiated for 4 cycles in total (50 mg/day; 4 weeks on/2 weeks off). The cytoreductive nephrectomy was performed following the fourth cycle of sunitinib and after a 14-day break. Transesophageal echocardiography was used for intraoperative monitoring of the caval vein thrombus. Systemic treatment with sunitinib was continued 4 weeks after surgery.

RESULTS

A significant reduction in tumor size, metastatic sites and down-staging of IVC from level IV to level III according to Novick classification was achieved.

CONCLUSION

Significant down-staging of the tumor caval vein thrombus which initially reached the right atrium enabled us to perform surgery limited to the abdominal cavity without extracorporeal circulation nor hypothermia.

[Metastasectomy in renal cell cancer after neoadjuvant therapy with multi-tyrosine kinase inhibitors]

BACKGROUND

Metastatic renal cell carcinoma (mRCC) still poses a challenge to therapists in spite of the availability of multiple innovative molecular treatment options. Complete remission is rare and in cases of partial remission it is often unclear if necrosis or vital carcinoma tissue persists. We report on a cohort of patients who underwent metastasectomy after neoadjuvant therapy with multi-tyrosine kinase inhibitors (MTKI).

METHODS

In 2009 a total of 11 patients (7 male and 4 female) underwent metastasectomy after achievement of ≥ 3 months stable partial remission. All patients received either sunitinib (n=7, mean 5.5 cycles), bevacizumab and interferon (IFN)-α2a (n=2, mean 8.5 months), temsirolimus (n=1, mean 9 months) or a combination of sunitinib followed by temsirolimus (n=1). Of the patients 7 presented with retroperitoneal lymph node metastases with a mean diameter of 3.5-12 cm, 2 patients with pulmonary metastases, 1 patient with lymph node and pancreas tail metastases and 1 female patient showed residual disease in the vena cava.

RESULTS

All metastases were completely resected with negative surgical margins. In 82% of the cases histologically active, Ki-67 positive renal cell cancer tissue was identified. The following adjunctive interventions were necessary: vena cava resection with vascular prosthesis and reimplantation of the renal vein (n=3), partial liver resection (n=1), splenectomy (n=1) and pancreas tail resection (n=1). There were no significant perioperative complications but 1 patient developed fascial dehiscence and underwent revision surgery and 1 patient developed clinically insignificant pancreatitis. After a median follow-up of 12 months (range 8-19 months) 5 patients had no recurrence and 6 of the patients showed liver (n=3), lung (n=2) or bone (n=1) recurrences from which 3 patients died.

CONCLUSIONS

Metastasectomy of mRCC is associated with a low rate of complications in experienced centers. Surgical resection of metastatic disease is indicated to achieve complete remission with a favorable prognosis because of biologically active kidney cancer tissue. Patients with isolated and resectable metastases are ideal candidates for such a procedure.

[Operative treatment of renal cell carcinoma]

Renal cell carcinoma represents the fifth most frequent malignant tumor in humans. At the time of diagnosis, 20% of the patients already manifest metastases. A further 20-30% of the patients develop systemic metastases in the postoperative course. Despite continued advances in pharmacological treatment options, cancer surgery tailored to the individual tumor findings constitutes the only curative treatment option.

Chemotherapeutic drugs sensitize human renal cell carcinoma cells to ABT-737 by a mechanism involving the Noxa-dependent inactivation of Mcl-1 or A1

BACKGROUND

Human renal cell carcinoma (RCC) is very resistant to chemotherapy. ABT-737 is a novel inhibitor of anti-apoptotic proteins of the Bcl-2 family that has shown promise in various preclinical tumour models.

RESULTS

We here report a strong over-additive pro-apoptotic effect of ABT-737 and etoposide, vinblastine or paclitaxel but not 5-fluorouracil in cell lines from human RCC. ABT-737 showed very little activity as a single agent but killed RCC cells potently when anti-apoptotic Mcl-1 or, unexpectedly, A1 was targeted by RNAi. This potent augmentation required endogenous Noxa protein since RNAi directed against Noxa but not against Bim or Puma reduced apoptosis induction by the combination of ABT-737 and etoposide or vinblastine. At the level of mitochondria, etoposide-treatment had a similar sensitizing activity and allowed for ABT-737-induced release of cytochrome c.

CONCLUSIONS

Chemotherapeutic drugs can overcome protection afforded by Mcl-1 and A1 through endogenous Noxa protein in RCC cells, and the combination of such drugs with ABT-737 may be a promising strategy in RCC. Strikingly, A1 emerged in RCC cell lines as a protein of similar importance as the well-established Mcl-1 in protection against apoptosis in these cells.

Role of surgery in advanced/metastatic renal cell carcinoma

Metastatic renal cell cancer (RCC) is a malignant disease without curative treatment. These patients are usually symptomatic and desperate for effective palliative treatment. Radiotherapy, chemotherapy, and hormonal therapy are not effective in these patients. A multimodal approach consisting of cytoreductive nephrectomy, systemic therapy (which includes cytokines or targeted molecules), and metastasectomy have been shown to be useful in prolonging the survival and improving the quality of life in a select group of patients with metastatic renal cancer. Patients with oligometastatic disease, good performance status, and delayed presentation of the secondaries have better results following this integrated approach. Although there is some controversy regarding the order in which nephrectomy and systemic therapy are to be instituted, well-controlled studies like the South West Oncology Group and European organization research and treatment of cancer have shown that upfront nephrectomy gives better survival compared to neoadjuvant systemic therapy followed by nephrectomy. This order is the standard presently. Of late, with better understanding of the genetic basis and the biology of the various subtypes of renal cell carcinoma, targeted molecular therapies have emerged as an equally effective alternative therapy to cytokines. Recent reports have proven that targeted therapy is more effective with comparable side effects. Metastasectomy in a subgroup of patients improves survival and quality of life specifically in those with lung secondaries and painful bone metastases.

[Impact of surgery for residual tumors after chemotherapy]

Metastases are a feature not only of local tumor manifestation but also of systemic disease. Thus, the question arises regarding the extent to which local therapy contributes to a systemic state of disease. With renal cell carcinoma, resection of pulmonary metastases is a common operation. Other sites should be considered individually. Only a well-defined subset of patients with metastasized urothelial carcinoma benefit from the resection of their metastases.

Frequent loss of expression of the pro-apoptotic protein Bim in renal cell carcinoma: evidence for contribution to apoptosis resistance

Renal cell carcinoma (RCC) is resistant to chemotherapy, and this resistance is mirrored by a high apoptosis resistance of many RCC lines in vitro. Here, we report the loss of the pro-apoptotic BH3-only protein Bim in a large part of clinical RCC cases and provide evidence for a functional relevance of this loss. Immunohistochemistry of clear cell renal cell carcinoma cases and corresponding normal kidney showed strong Bim reactivity in renal tubules of all cases but loss of Bim in 35 of 45 RCC samples. Out of nine RCC cell lines investigated, six showed strongly diminished or undetectable levels of Bim protein by western blotting. Four RCC lines of varying apoptosis sensitivity were analysed further. Bcl-2, Bcl-x(L), Mcl-1, Bax and Bak expression did not correlate with apoptosis sensitivity. All cell lines underwent apoptosis upon forced expression of Bax and Bim, suggesting an upstream difference. In all four lines, adriamycin induced p53 but not its targets Puma or Noxa. However, apoptosis sensitivity correlated with levels of Bim protein. Bim siRNA reduced apoptosis sensitivity in a susceptible cell line. Furthermore, inhibition of histone deacetylation restored Bim expression in cell lines. These data suggest that Bim has a function as a tumor suppressor in RCC.

Detection of circulating tumor cells in patients with renal cell carcinoma by reverse transcriptase polymerase chain reaction for G250/MNCA-9: results of a prospective trial

OBJECTIVES

Radical nephrectomy displays the standard procedure for patients with localized renal cell carcinoma. The transperitoneal approach is often favored compared to the retroperitoneal approach because of the early ligation of the renal vessels, thereby tumor cell shedding by manipulation of the tumor is thought to be avoided. The aim of our study was to investigate the influence of the surgical technique on intraoperative tumor cell shedding. Furthermore, we evaluated the clinical course of the patients being operated on with either method in terms of complications, postoperative recovery, and hospital stay.

METHODS

A total of 55 consecutive patients with renal tumors suspicious for malignancies were evaluated for this study. Peripheral blood samples were obtained from 44 patients at admission, intraoperatively (before and after kidney removal), and before discharge. Ribonucleic acid was extracted, converted to complementary deoxyribonucleic acid, and reverse transcriptase polymerase chain reaction (RT-PCR) with primers specific for G250/MNCA-9 was performed. Data regarding the clinical course of the patients were analyzed retrospectively by reviewing patient files.

RESULTS

The clinical course for patients undergoing retroperitoneal nephrectomy was statistically different compared to the transperitoneal approach group regarding operating time and duration of drains, favoring the retroperitoneal approach group. Evaluation of MNCA-9 RT-PCR revealed no difference according to operative technique, tumor-nodes-metastasis, or clinical tumor stage. Despite this result, we found positive RT-PCR signals for MNCA-9 in patients with transitional cell cancer of the renal pelvis and benign renal lesions.

CONCLUSIONS

There is no clinical relevant difference between the transperitoneal and retroperitoneal approaches for radical nephrectomy. Furthermore, the retroperitoneal approach does not bear the risk of intraoperative tumor cell shedding by the handling of the tumor.

Combination of surgery and immunotherapy in metastatic renal cell carcinoma

The treatment of choice for non-disseminated renal cell cancer (RCC) is surgery. However, the 5-year survival rates for all stages do not exceed 60%, even in contemporary series. Further improvement will most likely have to await the development of a more effective systemic therapy and the application of combined treatment modalities to counter the relatively high number of patients presenting with advanced stages. Whereas textbook belief up to the 1990s suggested refraining from surgical antitumor-therapy in the case of metastatic RCC, current strategies clearly advocate debulking tumor nephrectomy in the context of modern immunotherapies. This dramatic change of attitude stemmed from two randomized phase III trials conducted by EORTC and SWOG, including a combined analysis of both studies, in which cytoreductive tumor nephrectomy conveyed a significant survival benefit over immunotherapy alone. Concepts and progress in this field appear to be of major interest for modern oncologic urologists following the advent of immunotherapeutic strategies that require surgical intervention at some stage of the treatment cascade.

Preoperative imaging in renal cell cancer

Renal cell cancer (RCC) represents the fifth most common cancer in men, with a rising incidence. Radical cancer surgery remains the only curative treatment in localized and advanced RCC. Therefore, preoperative imaging is most important for the planning of the surgical approach and strategy. The aim of any preoperative imaging in RCC is to differentiate benign from malignant lesions, to adequately assess tumor size, localization and organ confinement, to identify lymph node and/or visceral metastases, and to reliably predict the presence and extent of any thrombus of the vena cava. It is our aim to review the current status of preoperative imaging modalities in RCC. Computed tomography (CT) remains the most appropriate imaging modality to differentiate benign from malignant lesions. Although RCC can appear as iso-, hyper- or hypodense lesions on native CT scans, it usually demonstrates a significant contrast enhancement of about 115 HU and intratumoral areas of necrosis following the intravenous application of contrast medium. Benign masses such as renal oncocytoma are most often homogenous lesions exhibiting hypodensity compared to the normal renal parenchyma following the i.v. application of contrast dye. CT accurately predicts the tumor size with only a 0.5 cm difference as compared to the pathological size of the lesion. The identification of lymph node metastases still remains a problem since the limiting size is 4 mm and CT will result in a false negative rate of about 10%, especially in the presence of micrometastases; the false positive rate of 3-43% is mainly due to reactive hyperplasia. New technologies, such as the multidetector CT with thin collimation and multiplanar reformatting, might result in a diagnostic improvement. The involvement of the adrenal gland can be accurately predicted by CT scans or MRI, allowing an adrenal sparing approach in the case of unsuspicious findings. The detection of visceral metastases appears to be crucial since it has been shown that even patients with metastatic disease might benefit from radical nephrectomy followed by systemic immunotherapy in the case of a good performance status, and the presence of lymph node and pulmonary metastases only. Involvement of the renal vein and the vena cava with tumor thrombus formation will change the surgical strategy. Preoperatively, the presence and the cranial extent of the thrombus need to be known in order to plan the surgical approach. With regard to the extent of renal vein thrombi, a three phase helical CT scan is most appropriate; for vena caval thrombi only a MRI examination is able to accurately identify any infra- or suprahepatic as well as intracardial extension of the thrombus. The identification of multifocal lesions remains another unsolved problem in preoperative imaging techniques for RCC. Compared to the pathohistological analysis of nephrectomy specimens, neither ultrasonography, color duplex sonography nor regular CT scans are able to identify multifocal lesions with acceptable sensitivity and specificity. The evaluation of unenhanced CT scans together with the enhanced corticomedullary and the nephrogenic phase result in a 100% sensitivity and might represent a valuable option. Angiography has basically been abandoned from the armory of routine imaging techniques. It has, however, a current role in terms of the embolization of large tumors to reduce intraoperative blood loss, and in the palliative management of pain and bleeding due to RCC not amenable to surgery. Finally, we present a diagnostic algorithm for the most informative imaging techniques in the evaluation of RCC.

Preoperative imaging in renal cell cancer

Renal cell cancer (RCC) represents the fifth most common cancer in men, with a rising incidence. Radical cancer surgery remains the only curative treatment in localized and advanced RCC. Therefore, preoperative imaging is most important for the planning of the surgical approach and strategy. The aim of any preoperative imaging in RCC is to differentiate benign from malignant lesions, to adequately assess tumor size, localization and organ confinement, to identify lymph node and/or visceral metastases, and to reliably predict the presence and extent of any thrombus of the vena cava. It is our aim to review the current status of preoperative imaging modalities in RCC. Computed tomography (CT) remains the most appropriate imaging modality to differentiate benign from malignant lesions. Although RCC can appear as iso-, hyper- or hypodense lesions on native CT scans, it usually demonstrates a significant contrast enhancement of about 115 HU and intratumoral areas of necrosis following the intravenous application of contrast medium. Benign masses such as renal oncocytoma are most often homogenous lesions exhibiting hypodensity compared to the normal renal parenchyma following the i.v. application of contrast dye. CT accurately predicts the tumor size with only a 0.5 cm difference as compared to the pathological size of the lesion. The identification of lymph node metastases still remains a problem since the limiting size is 4 mm and CT will result in a false negative rate of about 10%, especially in the presence of micrometastases; the false positive rate of 3-43% is mainly due to reactive hyperplasia. New technologies, such as the multidetector CT with thin collimation and multiplanar reformatting, might result in a diagnostic improvement. The involvement of the adrenal gland can be accurately predicted by CT scans or MRI, allowing an adrenal sparing approach in the case of unsuspicious findings. The detection of visceral metastases appears to be crucial since it has been shown that even patients with metastatic disease might benefit from radical nephrectomy followed by systemic immunotherapy in the case of a good performance status, and the presence of lymph node and pulmonary metastases only. Involvement of the renal vein and the vena cava with tumor thrombus formation will change the surgical strategy. Preoperatively, the presence and the cranial extent of the thrombus need to be known in order to plan the surgical approach. With regard to the extent of renal vein thrombi, a three phase helical CT scan is most appropriate; for vena caval thrombi only a MRI examination is able to accurately identify any infra- or suprahepatic as well as intracardial extension of the thrombus. The identification of multifocal lesions remains another unsolved problem in preoperative imaging techniques for RCC. Compared to the pathohistological analysis of nephrectomy specimens, neither ultrasonography, color duplex sonography nor regular CT scans are able to identify multifocal lesions with acceptable sensitivity and specificity. The evaluation of unenhanced CT scans together with the enhanced corticomedullary and the nephrogenic phase result in a 100% sensitivity and might represent a valuable option. Angiography has basically been abandoned from the armory of routine imaging techniques. It has, however, a current role in terms of the embolization of large tumors to reduce intraoperative blood loss, and in the palliative management of pain and bleeding due to RCC not amenable to surgery. Finally, we present a diagnostic algorithm for the most informative imaging techniques in the evaluation of RCC.

Preoperative imaging in renal cell cancer

Renal cell cancer (RCC) represents the fifth most common cancer in men, with a rising incidence. Radical cancer surgery remains the only curative treatment in localized and advanced RCC. Therefore, preoperative imaging is most important for the planning of the surgical approach and strategy. The aim of any preoperative imaging in RCC is to differentiate benign from malignant lesions, to adequately assess tumor size, localization and organ confinement, to identify lymph node and/or visceral metastases, and to reliably predict the presence and extent of any thrombus of the vena cava. It is our aim to review the current status of preoperative imaging modalities in RCC. Computed tomography (CT) remains the most appropriate imaging modality to differentiate benign from malignant lesions. Although RCC can appear as iso-, hyper- or hypodense lesions on native CT scans, it usually demonstrates a significant contrast enhancement of about 115 HU and intratumoral areas of necrosis following the intravenous application of contrast medium. Benign masses such as renal oncocytoma are most often homogenous lesions exhibiting hypodensity compared to the normal renal parenchyma following the i.v. application of contrast dye. CT accurately predicts the tumor size with only a 0.5 cm difference as compared to the pathological size of the lesion. The identification of lymph node metastases still remains a problem since the limiting size is 4 mm and CT will result in a false negative rate of about 10%, especially in the presence of micrometastases; the false positive rate of 3-43% is mainly due to reactive hyperplasia. New technologies, such as the multidetector CT with thin collimation and multiplanar reformatting, might result in a diagnostic improvement. The involvement of the adrenal gland can be accurately predicted by CT scans or MRI, allowing an adrenal sparing approach in the case of unsuspicious findings. The detection of visceral metastases appears to be crucial since it has been shown that even patients with metastatic disease might benefit from radical nephrectomy followed by systemic immunotherapy in the case of a good performance status, and the presence of lymph node and pulmonary metastases only. Involvement of the renal vein and the vena cava with tumor thrombus formation will change the surgical strategy. Preoperatively, the presence and the cranial extent of the thrombus need to be known in order to plan the surgical approach. With regard to the extent of renal vein thrombi, a three phase helical CT scan is most appropriate; for vena caval thrombi only a MRI examination is able to accurately identify any infra- or suprahepatic as well as intracardial extension of the thrombus. The identification of multifocal lesions remains another unsolved problem in preoperative imaging techniques for RCC. Compared to the pathohistological analysis of nephrectomy specimens, neither ultrasonography, color duplex sonography nor regular CT scans are able to identify multifocal lesions with acceptable sensitivity and specificity. The evaluation of unenhanced CT scans together with the enhanced corticomedullary and the nephrogenic phase result in a 100% sensitivity and might represent a valuable option. Angiography has basically been abandoned from the armory of routine imaging techniques. It has, however, a current role in terms of the embolization of large tumors to reduce intraoperative blood loss, and in the palliative management of pain and bleeding due to RCC not amenable to surgery. Finally, we present a diagnostic algorithm for the most informative imaging techniques in the evaluation of RCC.

Multimodality treatment of metastatic renal cell carcinoma

The treatment of choice for nondisseminated disease is surgery. However, the 5-year survival rates for all stages do not exceed 60%, even in contemporary series. Further improvement will most likely have to await the development of a more effective systemic therapy and the application of combined treatment modalities to counter the relatively high number of patients presenting with advanced stages. Treatment options in metastatic disease include nephrectomy, sometimes in combination with metastasectomy in selected cases, alone or cytoreductive surgery followed by immunotherapy. Alternatively, one may initially apply immunotherapy and perform adjuvant nephrectomy in the case of a response, or proceed to immunotherapy as a monotherapy. Nevertheless, long-term survival ranges from merely 5 to 10% depending strongly on patient selection criteria. Concepts and progress in this field appear to be of major interest for modern uro-oncologists following the advent of immunotherapeutic strategies that require a surgical intervention at some stage of the treatment cascade.