Presence of sarcomatoid differentiation as a prognostic indicator for survival in surgically treated metastatic renal cell carcinoma

Targeted gene sequencing reveals disparate genomic mutations between young and older adults in renal cell carcinoma

BACKGROUND

Renal cell carcinoma (RCC) is a type of cancer that can develop at any point in adulthood, spanning the range of age-related changes that occur in the body. However, the specific molecular mechanisms underlying the connections between age and genetic mutations in RCC have not been extensively investigated.

METHODS

Clinical and genetic data from patients diagnosed with RCC were collected from two prominent medical centers in China as well as the TCGA dataset. The patients were categorized into two groups based on their prognosticated age: young adults (YAs) and older adults (OAs). Univariate and multivariate analysis were employed to evaluate the relationships between age and genetic mutations. Furthermore, a mediation analysis was conducted to assess the association between age and overall survival, with genetic disparities serving as a mediator.

RESULTS

Our analysis revealed significant differences in clinical presentation between YAs and OAs with RCC, including histopathological types, histopathological tumor stage, and sarcomatoid differentiation. YAs were found to have lower mutation burden and significantly mutated genes (SMGs) of RCC. However, we did not observe any significant differences between the two groups in terms of 10 canonical oncogenic signaling pathways-related genes mutation, telomerase-related genes (TRGs) mutation, copy number changes, and genetic mutations associated with clinically actionable targeted drugs. Importantly, we demonstrate superior survival outcomes in YAs, and we confirmed the mediating effect of genetic disparities on these survival outcome differences between YAs and OAs.

CONCLUSION

Our findings reveal previously unrecognized associations between age and the molecular underpinnings of RCC. These associations may serve as valuable insights to guide precision diagnostics and treatments for RCC.

Demographic Patterns and Clinicopathological Analysis of Sarcomatoid Renal Cell Carcinoma in US Population

BACKGROUND

Sarcomatoid renal cell carcinoma (RCC) is defined by the presence of any amount of sarcomatoid components admixed with other RCC histologic subtypes. Our investigation utilizes a large, diverse set of sarcomatoid RCC patients to summarize clinical, demographic, and pathological factors along with demographic disparities that may affect the prognosis and survival of sarcomatoid RCC patients.

METHODS

The Surveillance, Epidemiology, and End Results (SEER) database was employed to compile data from 2000 to 2018 from 2695 patients diagnosed with sarcomatoid RCC.

RESULTS

The mean age for sarcomatoid RCC diagnosis is 62.8 years. Males (68.2%) and White patients (82.6%) were more likely to be diagnosed with sarcomatoid RCC. Among the 64.4% of tumors with known size, 35.4% were less than 7 cm, 27.6% were 7.1 to 10 cm, and 36.4% were larger than 10 cm. Among the 95.8% of patients with known stage, 15.3% were localized, 28.9% were regionalized, and 55.8% were found in distant sites. Among the 44.2% of cases with known metastases site, lung was found to be the most common metastatic site.. Surgery was the most common treatment (70.9%). While the overall 5-year survival was 18.1%, it was 27.1% among patients who underwent surgery. Independent risk factors for mortality include age > 60 years, distant stage, and tumor size > 10 cm, per our multivariate analysis.

CONCLUSION

Sarcomatoid RCC most commonly affects White males in their seventh decade. Increased age, distant stage, and size > 10 cm tumor size have associations with unfavorable prognosis. Surgery is associated with better survival outcomes in localized disease and multimodal therapy (surgery with adjuvant chemoradiation was associated with better survival.).

Concomitant Drug Treatment and Elimination in the RCC-affected Kidneys: Can We Kill Two Birds with One Stone?

BACKGROUND

The kidneys are vital organs acting as the body's filters that eliminate drugs and other waste products from the body. For effective cancer therapy, a delicate balance is required in the drug treatment and its elimination, which is critical for drug accumulation, toxicity, and kidney malfunction. However, how renal cell carcinoma (RCC) affects the kidneys in safely eliminating the byproducts of drug treatments in patients with severely dysregulated kidney functions had remained elusive. Recent advancements in dose adjustment have added to our understanding regarding how drug treatments could be effectively regulated in aberrant kidney cells, driving safe elimination and reducing drug accumulation and toxicity at the right time and space. Dose adjustment is the only standard systemic way applicable; however, it presents certain limitations. There is significant room for developing new strategies and alternatives to improve it.

OBJECTIVES

Our analysis of the available treatments in literature discusses the treatment and their safe eliminations. In this study, we give an overview of the measures that could be taken to maintain the elimination gradient of anti-cancer drugs and restore normal kidney function in RCC. Differential therapeutics of RCC/mRCC in various clinical phase trials and the interaction of targeted therapeutics in response to vascular endothelial growth factor (VEGF) were also discussed.

CONCLUSION

Such information might suggest a new direction in controlling treatment with safe elimination through dose adjustment and its associated alternatives in a judicious manner. A strategy to systematically focus on the safe elimination of anti-cancer drugs in RCC strongly needs advocating.

Prognostic Significance of Sarcomatoid Differentiation in Patients With Metastatic Renal Cell Carcinoma: A Systematic Review and Meta-Analysis

Background

To date, the prognostic value of sarcomatoid differentiation in patients having metastatic renal cell carcinoma (mRCC) remains inconclusive. A systematic review and meta-analysis were conducted.

Materials and Methods

Relevant literatures were obtained from PubMed, Embase, and Cochrane Library published prior to May, 2020. All patients were diagnosed with mRCC and treated with surgery, cytokine therapy, targeted therapy, and immunotherapy. Sarcomatoid differentiation in the pathological specimens was identified. Each endpoint [overall survival (OS), progression-free survival (PFS), and cancer-specific survival (CSS)] was assessed using a multivariable adjusted hazard ratio (HR) and 95% confidence interval (CI).

Results

Fifteen observational studies having 5,828 patients with mRCC were included. The merged results showed that patients presenting sarcomatoid differentiation had a significantly inferior OS (HR: 2.26, 95% CI: 1.82-2.81; P < 0.001), PFS (HR: 2.28, 95% CI: 1.63-3.19; P < 0.001), and CSS (HR: 2.27, 95% CI: 1.51-3.40; P < 0.001) compared to those without sarcomatoid differentiation. Subgroup analysis based on publication year, patient population, country, number of cases, and NOS score did not change the direction of results. A significant publication bias was identified for OS, but no publication bias was identified for PFS. Moreover, sensitivity analysis also verified the robustness of the results.

Conclusion

This study suggested that sarcomatoid differentiation was correlated to unfavorable clinical outcomes in mRCC and may be a poor prognostic factor incorporating to prognostic models for mRCC patients.

Sarcomatoid renal cell carcinoma: biology, natural history and management

Sarcomatoid dedifferentiation is an uncommon feature that can occur in most histological subtypes of renal cell carcinomas (RCCs) and carries a decidedly poor prognosis. Historically, conventional treatments for sarcomatoid RCCs (sRCCs) have shown little efficacy, and median survival is commonly 6–13 months. Despite being first described in 1968, the mechanisms driving sarcomatoid dedifferentiation remain poorly understood, and information and treatment options available to physicians and patients are limited. When diagnosed at an early stage, surgical intervention remains the treatment of choice. However, preoperative identification through routine imaging or biopsy is unreliable and most patients present with advanced disease and systemic symptoms. For these patients, the role of cytoreductive nephrectomy is disputed. The expansion of immunotherapies approved for RCCs has generated a search for biomarkers that might be indicative of treatment response in sRCCs, although a proven effective systemic agent remains elusive. PDL1 expression is increased in sarcomatoid dedifferentiated renal tumours, which suggests that patients with sRCCs could benefit from PD1 and/or PDL1 immune checkpoint blockade therapy. Treatment outcomes for sarcomatoid tumours have remained relatively consistent compared with other RCCs, but further investigation of the tumour–immune cell microenvironment might yield insights into further therapeutic possibilities.

In this Review, Blum et al. summarize the current knowledge on sarcomatoid renal cell carcinoma, a diagnosis characterized by the presence of sarcomatoid dedifferentiation and a poor prognosis. They discuss the origin, presentation, molecular biology and treatment of this disease.

Sarcomatoid dedifferentiation is not considered to be a unique histological subtype of renal cell carcinomas (RCCs); rather, it can be present within any subtype of RCCs.

Sarcomatoid dedifferentiation appears in ~4% of all RCCs, but is present in ~20% of all metastatic RCCs. According to WHO guidelines, any RCC with sarcomatoid dedifferentiation is a WHO–International Society of Urological Pathology grade 4 lesion.

Sarcomatoid dedifferentiation is often heterogeneously present within RCCs, making routine imaging and biopsy unreliable for preoperative detection. Surgical resection for localized disease is the standard of care, with subsequent close monitoring of patients following surgery.

In patients with metastatic disease, conventional therapies such as surgery and systemic agents have been ineffective and overall 5-year survival remains at 23.5–33%.

Previous genomic analyses have failed to identify definitive mutational drivers of disease. However, sarcomatoid RCCs (sRCCs) have been shown to have higher PD1 and PDL1 expression than other subtypes of RCCs. Newer combinations of immune checkpoint inhibitor immunotherapies could yield improved responses and outcomes.

Studies investigating sRCCs are limited by patient numbers owing to the low incidence of sRCCs and their advanced stage at presentation. Multi-institutional efforts to establish a consensus on treatment recommendations based on highly powered data are essential.

Cytoreductive Nephrectomy in Patients Presenting With Advanced Disease: Have We Finally Answered the Question?

Determining the appropriate patients for cytoreductive nephrectomy (CN) has evolved with the integration of more effective systemic therapies for patients with metastatic renal cell carcinoma (mRCC). While previously considered to be first-line therapy for mRCC, CN has not demonstrated a significant survival advantage over systemic therapy in more recent randomized trials when compared with targeted therapy. Conversely, multiple observational studies demonstrate a therapeutic benefit for CN. This review synthesizes the current literature regarding patient selection for CN and further evaluates the role of CN in the current era of immune checkpoint inhibitor therapy. With careful patient selection, CN maintains an important role in the management of mRCC patients.

Impact of sarcomatoid differentiation and rhabdoid differentiation on prognosis for renal cell carcinoma with vena caval tumour thrombus treated surgically

Background

Sarcomatoid differentiation in renal cell carcinoma (RCC) with vena caval tumour thrombus has been shown to be associated with aggressive behaviours and poor prognosis; however, evidence of the impact of rhabdoid differentiation on prognosis is lacking. This study evaluated the impact of sarcomatoid differentiation and rhabdoid differentiation on oncological outcomes for RCC with vena caval tumour thrombus treated surgically.

Methods

We retrospectively analysed patients treated surgically for RCC with vena caval tumour thrombus at our institute from Jan 2015 to Nov 2018. Prognostic variables were evaluated for associations with progression-free survival (PFS) and cancer-specific survival (CSS) by Kaplan–Meier survival analysis and log-rank test. Univariate and multivariate analyses were performed to determine independent prognostic variables.

Results

We identified 125 patients with RCC and vena caval tumour thrombus, including 17 (13.6%) with sarcomatoid differentiation alone, 8 (6.4%) with rhabdoid differentiation alone and 3 (2.4%) with both sarcomatoid and rhabdoid differentiation. Compared to pure RCC, patients with sarcomatoid differentiation but not rhabdoid differentiation have worse PFS (p = 0.018 and p = 0.095, respectively). The univariate and multivariate analyses both showed sarcomatoid differentiation as a significant predictor of PFS. Compared to pure RCC, patients with sarcomatoid differentiation (p = 0.002) and rhabdoid differentiation (p = 0.001) both had significantly worse CSS. The univariate analysis showed sarcomatoid differentiation, rhabdoid differentiation, metastasis and blood transfusion as significant predictors of CSS (All, p < 0.05). In the multivariate analysis, sarcomatoid differentiation (HR 3.90, p = 0.008), rhabdoid differentiation (HR 3.01, p = 0.042), metastasis (HR 3.87, p = 0.004) and blood transfusion (HR 1.34, p = 0.041) all remained independent predictors of CSS.

Conclusions

Sarcomatoid differentiation and rhabdoid differentiation are both independent predictors of poor prognosis in RCC with vena caval tumour thrombus treated surgically.

Histologic Subtype, Tumor Grade, Tumor Size, and Race Can Accurately Predict the Probability of Synchronous Metastases in T2 Renal Cell Carcinoma

BACKGROUND

We investigated the association between synchronous metastases (SMs), histologic subtype (HS), tumor size (TS), and tumor grade (TG) in surgically treated stage T2 renal cell carcinoma (RCC).

MATERIALS AND METHODS

Within the Surveillance, Epidemiology, and End Results database (2005-2015), 8344 patients with T2 RCC who had undergone radical nephrectomy were identified. The SM rates were tabulated according to the HS, TG, and TS and tested in multivariable logistic regression models.

RESULTS

According to the HS, the average SM rates were 0%, 1.4%, 4.6%, 6.4%, 12.7%, 20.0%, and 32.7% for multilocular cystic, chromophobe, papillary, TG 1-2 clear cell, TG 3-4 clear cell, collecting duct, and sarcomatoid dedifferentiation RCC, respectively. In multivariable logistic regression models predicting for SMs, HS represented the strongest predictor, followed by TG, TS, and race. When combined, HS, TG, TS, and race predicted for SMs with 70.2% accuracy compared with 62.5% with HS, 60.2% with TG, 57.8% with TS, and 53.0% with race alone. Lung only was the most common metastatic site (43.6%), followed by bone only (27.6%), liver only (4.4%), and brain only (4.4%). Of all the patients with SMs, 78.9% had a single metastatic site.

CONCLUSIONS

The SM rates showed very wide variation according to the HS, TG, and TS. When HS was combined with TG, TS, and race, SMs could be accurately predicted in individual patients better than with TS alone. Thus, renal mass biopsy-derived HS and TG could improve the prediction of SMs compared with using TS alone.

The Association Between Small Primary Tumor Size and Prognosis in Metastatic Renal Cell Carcinoma: Insights from Two Independent Cohorts of Patients Who Underwent Cytoreductive Nephrectomy

BACKGROUND

One of the main challenges in the management of renal cell carcinoma (RCC) is risk-stratifying patients who present with metastatic disease. Tumor size is an important predictor of survival in the localized setting; however, this feature has not been explored fully in patients presenting with M1 RCC.

OBJECTIVE

To assess the impact of tumor size on survival in patients with metastatic RCC who underwent cytoreductive nephrectomy (CN).

DESIGN, SETTING, AND PARTICIPANTS

We queried the Memorial Sloan Kettering (MSK) nephrectomy database for patients who presented with M1 disease and underwent CN between 1989 and 2016 (n=304). Primary tumor size was obtained from pathology reports. Data from the International Metastatic Database Consortium (IMDC) were used for validation purposes (n=778).

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Overall survival (OS) estimates were computed using the Kaplan-Meier method. Cox regressions were used to test the association between tumor size and OS in univariate and multivariable analyses. Tumors ≤4cm were compared with larger masses. Secondary analyses were performed to assess the robustness of these findings.

RESULTS AND LIMITATIONS

Clear cell tumors ≤4cm were significantly associated with improved OS in both the MSK (hazard ratio [HR]: 0.35, 0.17-0.72, p= 0.004) and IMDC (HR 0.54, 0.36-0.83, p= 0.004) cohorts. The association was observed even after adjusting for known prognostic factors (HR 0.40, 0.14-1.14, p= 0.09 and HR: 0.54, 0.33-0.90, p= 0.02 in the MSK and IMDC cohorts, respectively). Limitations of this study include the absence of patients who were considered poor surgical candidates as well as potential selection bias.

CONCLUSIONS

The primary tumor size ≤4cm was independently associated with improved OS in patients with metastatic clear cell RCC who underwent CN. Additionally, the association between primary size and survival was found to be nonlinear. These findings suggest that there is a group of small metastatic RCCs that can convey a better overall prognosis. The potential role of primary tumor size when risk stratifying patients with M1 RCC should be explored further to determine its utility during clinical decision making.

PATIENT SUMMARY

We evaluated the impact of small tumor size on prognosis in patients with metastatic kidney cancer who undergo removal of the primary tumor. Very small masses (≤4cm) were associated with better prognosis in patients with clear cell tumors.

The Role of Cytoreductive Nephrectomy for Sarcomatoid Renal Cell Carcinoma: A 29-Year Institutional Experience

OBJECTIVE

To assess which patients respond best following cytoreductive nephrectomy for renal cell carcinoma (RCC) with sarcomatoid dedifferentiation (sRCC) and whether outcomes are improving over time.

METHODS

We identified 562 patients with metastatic RCC treated between 1989 and 2018 with cytoreductive nephrectomy. We reviewed baseline clinical and pathologic characteristics, including the presence of sRCC, and metastatic sites at time of nephrectomy. The primary study endpoint was overall survival (OS). Univariate and multivariate Cox-regression analyses were used to identify significant predictors of OS.

RESULTS

The study cohort had 192 sRCC patients, with a median age of 59 years. Frequently involved metastatic locations were lung (n = 115), retroperitoneal nodes (n = 63), and axial skeleton (n = 43). Lung metastasis were more prevalent in clear cell histology (P = .0017) whereas nodal involvement was associated with nonclear cell subtypes (P = .0064). Median follow-up was 14 months. Estimated 2- and 5-year OS were 34.1% and 14.8%, respectively. On multivariate analysis, metastases to the liver (HR = 1.64; 95% CI 1.02-2.63; P = .04), lung (HR = 1.50; 95% CI 1.05-2.14; P = .03), retroperitoneal nodes (HR = 1.52; 95% CI 1.03-2.25; P = 0.04) and nonclear cell histology (HR = 1.61; 95% CI 1.10-2.35; P = .01) were associated with worse OS in the sRCC cohort.

CONCLUSION

OS after cytoreductive nephrectomy for sRCC and non-sRCC is improving over time. In patients with sRCC, presentations with unifocal metastasis not involving the liver or lung, clear cell histology and node negative disease have better outcomes following cytoreductive nephrectomy and may yield greater benefit from the procedure.

Sarcomatoid Renal Cell Carcinoma: Population-Based Study of 879 Patients

BACKGROUND

Sarcomatoid renal cell carcinoma (sRCC) constitutes a rare and aggressive subtype of renal cell carcinoma. We aimed to investigate its clinicopathologic characteristics and outcomes at a national level.

PATIENTS AND METHODS

We accessed the National Cancer Institute's Surveillance, Epidemiology, and End Results database (2010-2015) and extracted data on patients with sRCC. We estimated median, 1-, 3-, and 5-year disease-specific survival (DSS) probabilities after generation of Kaplan-Meier curves and used multivariable regression to evaluate variables associated with nephrectomy and DSS.

RESULTS

A total of 879 patients with sRCC were identified; 60.9% patients had stage IV disease at diagnosis, and the median tumor size was 8.3 cm (interquartile range, 5.5-12 cm). The 5-year DSS were 77.7%, 67.8%, 35.4%, and 3.5% for patients with stage I, II, III, and IV disease at diagnosis, respectively; median DSS was 9 months (interquartile range, 4-42 months) for the entire cohort. Older age (hazard ratio [HR] = 1.01; 95% confidence interval [CI], 1.00-1.02), higher tumor stage (stage III vs. I: HR = 3.81; 95% CI, 2.18-6.67; stage IV vs. I: HR = 9.89; 95% CI, 5.80-16.98), and performance of nephrectomy (HR = 0.53; 95% CI, 0.43-0.66) were found to independently affect DSS.

CONCLUSION

In the largest sRCC cohort to date, we found that most patients present with metastatic disease, and the prognosis for this disease remains extremely poor. Nephrectomy should be considered in all patients with acceptable surgical risk, including cytoreductive nephrectomy in carefully selected patients with metastatic disease.

Mutations in renal cell carcinoma

Renal cell carcinoma (RCC) is a commonly diagnosed and histologically diverse urologic malignancy. Clear cell RCC (ccRCC) is by far the most common, followed by the papillary and chromophobe subtypes. Sarcomatoid differentiation is a morphologic change that can be seen in all subtypes that typically portends a poor prognosis. In the past, treatment options for RCC were limited to cytokine-based therapy with a high-toxicity profile and low response rate. An increased understanding of the molecular basis of RCC has led to substantial improvement in treatment options in the form of targeted therapy and immunotherapy. A significant early discovery in RCC was frequent inactivation of the Von Hippel Lindau gene in ccRCC, which ultimately led to the development of vascular endothelial growth factor and mammalian target of rapamycin inhibitors. Further genomic sequencing of ccRCC tumors has identified other common mutations including BAP-1, PBRM1, SETD2, and PIK3CA. Many recent studies have explored how these mutations can affect prognosis and response to treatment. Likewise, papillary RCC has also been studied at the molecular level, which has shown a high level of mutations in the MET gene; early clinical data suggest the utility of MET targeted therapy. Finally, regarding the rarer sarcomatoid tumors, mutations in TP53 and NF2 may be important to their development. As we continue to learn more about what drives RCC at the molecular level, treatment options for RCC patients are diversifying.

Tumor necrosis as a prognostic variable for the clinical outcome in patients with renal cell carcinoma: a systematic review and meta-analysis

Background

Tumor necrosis (TN) correlates with adverse outcomes in numerous solid tumors. However, its prognostic value in renal cell carcinoma (RCC) remains unclear. In this study, we performed a meta-analysis to evaluate associations between TN and cancer-specific survival (CSS), overall survival (OS), recurrence-free survival (RFS) and progression-free-survival (PFS) in RCC.

Methods

Electronic searches in PubMed, EMBASE and Web of Science were conducted according to the PRISMA statement. Hazard ratios (HRs) and 95% confidence intervals (95% CIs) were calculated to evaluate relationships between TN and RCC. A fixed- or random-effects model was used to calculate pooled HRs and 95%CIs according to heterogeneity.

Results

A total of 34 cohort studies met the eligibility criteria of this meta-analysis. The results showed that TN was significantly predictive of poorer CSS (HR = 1.37, 95% CI: 1.23–1.53, p < 0.001), OS (HR = 1.29, 95% CI: 1.20–1.40, p < 0.001), RFS (HR = 1.55, 95% CI: 1.39–1.72, p < 0.001) and PFS (HR = 1.31, 95% CI: 1.17–1.46, p < 0.001) in patients with RCC. All the findings were robust when stratified by geographical region, pathological type, staging system, number of patients, and median follow-up.

Conclusions

The present study suggests that TN is associated with CSS, OS, RFS and PFS clinical outcomes of RCC patients and may serve as a predictor of poor prognosis in these patients.

Electronic supplementary material

The online version of this article (10.1186/s12885-018-4773-z) contains supplementary material, which is available to authorized users.

The prognostic value and clinicopathological features of sarcomatoid differentiation in patients with renal cell carcinoma: a systematic review and meta-analysis

Background and purpose

Numerous studies have demonstrated that sarcomatoid differentiation is linked to the risk of renal cell carcinoma (RCC). However, its actual clinicopathological impact remains inconclusive. Therefore, we undertook a meta-analysis to evaluate the pathologic and prognostic impacts of sarcomatoid differentiation in patients with RCC by assessing cancer-specific survival, overall survival, recurrence-free survival, progression-free survival, and cancer-specific mortality.

Materials and methods

In accordance with the preferred reporting items for systematic reviews and meta-analysis statement, relevant studies were collected systematically from PubMed, Embase, and Web of Science to identify relevant studies published prior to January 2018. The pooled effects (hazard ratios, odds ratios, and standard mean differences) and 95% confidence intervals were calculated to investigate the association of sarcomatoid differentiation with cancer prognosis and clinicopathological features.

Results

Thirty-five studies (N=11,261 patients [n=59-1,437 per study]) on RCC were included in this meta-analysis. Overall, the pooled analysis suggested that sarcomatoid differentiation was significantly associated with unfavorable cancer-specific survival (HR=1.46, 95% CI: 1.26-1.70, p<0.001), overall survival (HR=1.59, 95% CI: 1.42-1.78, p<0.001), progression-free survival (HR=1.61, 95% CI: 1.35-1.91, p<0.001), recurrence-free survival (HR=1.60, 95% CI: 1.29-1.99, p<0.001), and cancer-specific mortality (HR=2.36, 95% CI: 1.64-3.41, p<0.001) in patients with RCC. Moreover, sarcomatoid differentiation was closely correlated with TNM stage (III/IV vs I/II: OR=1.84, 95% CI: 1.12-3.03, p=0.017), Fuhrman grade (III/IV vs I/II: OR=8.37, 95% CI: 2.92-24.00, p<0.001), lymph node involvement (N1 vs N0: OR=1.88, 95% CI: 1.08-3.28, p=0.026), and pathological types (clear cell RCC-only vs mixed type: OR=0.48, 95% CI: 0.29-0.80, p=0.005), but was not related to gender (male vs female, OR=0.86, 95% CI: 0.58-1.28, p=0.464) and average age (SMD=-0.02, 95% CI: -0.20-0.17, p=0.868).

Conclusion

This study suggests that sarcomatoid differentiation in histopathology is associated with poor clinical outcome and advanced clinicopathological features in RCC and could serve as a poor prognostic factor for RCC patients.

Epidemiology, biology and treatment of sarcomatoid RCC: current state of the art

Long recognized to confer an extremely poor prognosis, sarcomatoid dedifferentiation of renal cell carcinoma (sRCC) is a tumor phenotype that is finally beginning to be better understood on the molecular and genetic levels. With an overall incidence that ranges from 1 to 32% depending on associated RCC subtype, the survival of sarcomatoid RCC patients rarely exceeds 2 years. The main reasons for its poor outcome include its aggressive biology, its tendency to present at an advanced or metastatic stage at the time of diagnosis, its high rate of tumor recurrence after nephrectomy, and its limited response to systemic therapies. Molecular pathology studies suggest that sarcomatoid dedifferentiation originates from a focal epithelial-mesenchymal transition (EMT) arising in the carcinomatous component of the tumor. It is hoped that the growing understanding of the molecular biology of sRCC will soon make it possible to adapt treatments based on the identification of actionable tumor alterations. The deliberate inclusion of these patients in the multicenter clinical trials of immune, targeted and combination therapies is a necessary next step in pioneering future treatment strategies.

FDG PET/CT of Chromophobe Renal Cell Carcinoma With Sarcomatoid Differentiation

We report the case of a 49-year-old white man with a chromophobe renal cell carcinoma associated with sarcomatoid differentiation, an uncommon yet an aggressive form of dedifferentiated renal cell carcinoma. In opposite to the conventional renal cell carcinoma, which may not always demonstrate avid FDG activity, the sarcomatoid differentiated chromophobe renal cell carcinoma shows intense FDG uptake on PET. This case highlights the role of FDG PET/CT in staging and restaging this type of rare renal cell carcinoma.

Rapid recurrence and radiographic progression of sarcomatoid renal cell carcinoma

Sarcomatoid renal cell carcinoma (sRCC) is an aggressive variant of renal cell carcinoma (RCC) that has a significantly lower overall survival. Even after prompt surgical extirpation, this histologic variant progresses rapidly. We present a case of an early recurrence and rapid progression of sRCC despite successful radical resection.