Prognostic implications of sarcomatoid and rhabdoid differentiation in patients with grade 4 renal cell carcinoma

Sarcomatoid and Rhabdoid Renal Cell Carcinoma: Clinical, Pathologic, and Molecular Genetic Features

Renal cell carcinoma (RCC) with sarcomatoid and rhabdoid morphologies has an aggressive biological behavior and a typically poor prognosis. The current 2022 WHO classification of renal tumors does not include them as distinct histologic entities but rather as transformational changes that may arise in a background of various distinct histologic types of RCC. The sarcomatoid component shows malignant spindle cells that may grow as intersecting fascicles, which is reminiscent of pleomorphic undifferentiated sarcoma. The rhabdoid cells are epithelioid cells with eccentrically located vesicular nuclei with prominent nucleoli and large intracytoplasmic eosinophilic inclusions. Studies have shown that RCCs with sarcomatoid and rhabdoid differentiation have distinctive molecular features. Sarcomatoid RCC harbors shared genomic alterations in carcinomatous and rhabdoid components, but also enrichment of specific genomic alterations in the sarcomatoid element, suggesting molecular pathways for development of sarcomatoid growth from a common clonal ancestor. Rhabdoid differentiation also arises through clonal evolution although less is known of specific genomic alterations in rhabdoid cells. Historically, treatment has lacked efficacy, although recently immunotherapy with PD-1/PD-L1/CTLA-4 inhibitors has produced significant clinical responses. Reporting of sarcomatoid and rhabdoid features in renal cell carcinoma is required by the College of American Pathologists and the International Collaboration on Cancer Reporting. This manuscript reviews the clinical, pathologic, and molecular features of sarcomatoid RCC and rhabdoid RCC with emphasis on the morphologic features of these tumors, significance of diagnostic recognition, the molecular mechanisms of tumorigenesis and differentiation along sarcomatoid and rhabdoid lines, and advances in treatment, particularly immunotherapy.

Cytoreductive Nephrectomy for Patients with Metastatic Sarcomatoid and/or Rhabdoid Renal Cell Carcinoma Treated with Immune Checkpoint Therapy

BACKGROUND

Renal cell carcinoma (RCC) with sarcomatoid and/or rhabdoid (S/R) dedifferentiation is a highly aggressive tumor with a poor prognosis. Immune checkpoint therapy (ICT) has shown significant treatment efficacy in this subtype. There remains uncertainly regarding the role of cytoreductive nephrectomy (CN) for patients with metastatic RCC (mRCC) with S/R who received ICT.

OBJECTIVE

Here, we report the outcomes with ICT for patients with mRCC and S/R dedifferentiation by CN status.

DESIGN, SETTING, AND PARTICIPANTS

A retrospective review was conducted of 157 patients with sarcomatoid, rhabdoid, or sarcomatoid plus rhabdoid dedifferentiation who received an ICT-based regimen at two cancer centers.

INTERVENTION

CN performed at any time point; nephrectomy with curative intent was excluded.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

ICT treatment duration (TD) and overall survival (OS) from ICT initiation were recorded. To address the immortal time bias, a time-dependent Cox regression model was generated that accounted for confounders identified by a directed acyclic graph as well as a time-dependent nephrectomy variable.

RESULTS AND LIMITATIONS

A total of 118 patients underwent CN, and of them, 89 underwent upfront CN. The results did not contradict the supposition that CN does not improve ICT TD (hazard ratio [HR] 0.98, 95% confidence interval [CI] 0.65-1.47, p = 0.94) or OS from ICT initiation (HR 0.79, 95% CI 0.47-1.33, p = 0.37). In patients who underwent upfront CN compared with those who did not undergo CN, there was no association with ICT duration or OS (HR 0.61, 95% CI 0.35-1.06, p = 0.08). A detailed clinical summary of 49 patients with mRCC and rhabdoid dedifferentiation is provided.

CONCLUSIONS

In this multi-institutional cohort of mRCC with S/R dedifferentiation treated with ICT, CN was not significantly associated with improved TD or superior OS when accounting for the lead time bias. There appears to be a subset of patients who derive meaningful benefit from CN, so improved tools for stratification prior to CN are needed to optimize outcomes.

PATIENT SUMMARY

Immunotherapy has improved outcomes for patients with metastatic renal cell carcinoma (mRCC) who have sarcomatoid and/or rhabdoid (S/R) dedifferentiation, which is an aggressive and uncommon feature; yet, the utility of a nephrectomy in this setting is unclear. We found that nephrectomy did not significantly improve survival or time on immunotherapy for these patients with mRCC and S/R dedifferentiation; yet, there may be a subset of patients who benefit from this surgical approach.

Prognostic impact of CD73/adenosine 2A receptor (A2AR) in renal cell carcinoma and immune microenvironmental status with sarcomatoid changes and rhabdoid features

One of the most aggressive forms of kidney cancer is renal cell carcinoma (RCC) with sarcomatoid changes and rhabdoid features (S/R). Adenosine produced via CD73 binds to adenosine 2 A receptor (A2AR) and suppress antitumor immunity. Here, we attempted to analyze the expression of CD73/A2AR in S/R RCC and examined its relationships with other immune microenvironments and prognostic effect. Sixty cases of S/R RCC were selected. CD73/A2AR expression levels were graded in the tumor cells or infiltrating immune cells on a score of 0-3 and divided into low (0 or 1) or high (2 or 3) groups. PD-L1 results were defined by the tumor proportion score (TPS). We counted the numbers of CD8⁺, FOXP3⁺, CD68⁺, and CD163⁺ immune cells. The rates of CD73/A2AR expression in epithelial component (23.3% and 15.0%) were lower than those in high-grade component (70.0% and 45.0%). CD73/A2AR were significantly correlated to high numbers of regulatory Tcells and macrophages of M2 subtype (CD73: P = 0.0059 and 0.0002; A2AR: P = 0.0002 and 0.018, respectively). Multivariate analysis showed that CD73/A2AR expressions were independent markers of unfavorable prognosis in S/R RCCs (P = 0.0204 and 0.0116, respectively). In RCC, the S/R component had higher expressions of CD73/A2AR than the epithelial component, and CD73/A2AR were independent prognostic factors. Compared with other RCCs, S/R RCCs are more effective at blocking adenosine signaling and CD73/A2AR inhibitors are expected to enhance the therapeutic efficacy and improve the prognosis of immune checkpoint inhibitor therapies.

The significance of sarcomatoid and rhabdoid dedifferentiation in renal cell carcinoma

Dedifferentiation in renal cell carcinoma (RCC), either sarcomatoid or rhabdoid, is an infrequent event that may occur heterogeneously in the setting of any RCC histology and is associated with poor outcomes. Sarcomatoid dedifferentiation is associated with inferior survival with angiogenesis targeted therapy and infrequent responses to cytotoxic chemotherapy. However, immune checkpoint therapy has significantly improved outcomes for patients with sarcomatoid dedifferentiation. Biologically, sarcomatoid dedifferentiation has increased programmed death-ligand 1 (PD-L1) expression and an inflamed tumor microenvironment, in addition to other distinct molecular alterations. Less is known about rhabdoid dedifferentiation from either a clinical, biological, or therapeutic perspective. In this focused review, we will discuss the prognostic implications, outcomes with systemic therapy, and underlying biology in RCC with either sarcomatoid or rhabdoid dedifferentiation present.

Development and internal validation of nomograms for the prediction of postoperative survival of patients with grade 4 renal cell carcinoma (RCC)

Background

To develop successful prognostic models for grade 4 renal cell carcinoma (RCC) following partial nephrectomy and radical nephrectomy.

Methods

The nomograms were established based on a retrospective study of 135 patients who underwent partial and radical nephrectomy for grade 4 RCC at the Department of Urology, Peking University First Hospital from January 2013 to October 2018. The predictive performance of the nomograms was assessed by the calibration plot and C-index. The results were validated using bootstrap resampling.

Results

Aspartate transaminase (AST), the maximum diameter of tumor (cutoff value =7 cm), lymph node metastasis, and the International Metastatic Renal Cell Carcinoma Database Consortium (IMDC) risk group were independent factors for determining the overall survival (OS) and cancer-specific survival (CSS) in multivariate analysis. AST, the maximum diameter of the tumor (cutoff value =7 cm), and lymph node metastasis were found to be independent variables for progression-free survival (PFS) in multivariate analysis. These variables were used for the studies to establish nomograms. All calibration plots revealed excellent predictive accuracy of the models. The C-indexes of the nomograms for predicting OS, CSS and PFS were 0.729 (95% CI, 0.659-0.799), 0.725 (95% CI, 0.654-0.796) and 0.702 (95% CI, 0.626-0.778), respectively. Moreover, the recurrence rate was not associated with open or laparoscopic radical nephrectomy in our cohort (P=0.126).

Conclusions

We have developed easy-to-use models that are internally validated to predict postoperative 1-, 3-, and 5-year OS, CSS, and PFS rates of grade 4 RCC patients. The new models could aid in identifying high-risk patients, making postoperative therapeutic and follow-up strategies as well as predicting patients' survival after externally validated. Besides, our study shows that the recurrence rate is not associated with open or laparoscopic radical nephrectomy.

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.

Fumarate hydratase as a therapeutic target in renal cancer

INTRODUCTION

Renal cell carcinoma (RCC) is a heterogeneous group of cancers that can occur sporadically or as a manifestation of various inherited syndromes. Hereditary leiomyomatosis and renal cell carcinoma (HLRCC) is one such inherited syndrome that predisposes patients to HLRCC-associated RCC. These tumors are notoriously aggressive and often exhibit early metastases. HLRCC results from germline mutations in the FH gene, which encodes the citric acid cycle enzyme fumarate hydratase (FH). FH loss leads to alterations in oxidative carbon metabolism, necessitating a switch to aerobic glycolysis, as well as a pseudohypoxic response and consequent upregulation of various pro-survival pathways. Mutations in FH also alter tumor cell migratory potential, response to oxidative stress, and response to DNA damage.

AREAS COVERED

We review the mechanisms by which FH loss leads to HLRCC-associated RCC and how these mechanisms are being rationally targeted.

EXPERT OPINION

FH loss results in the activation of numerous salvage pathways for tumor cell survival in HLRCC-associated RCC. Tumor heterogeneity requires individualized characterization via next-generation sequencing, ultimately resulting in HLRCC-specific treatment regimens. As HLRCC-associated RCC represents a classic Warburg tumor, targeting aerobic glycolysis is particularly promising as a future therapeutic avenue.

The SWI/SNF chromatin-remodeling complex status in renal cell carcinomas with sarcomatoid or rhabdoid features

The presence of sarcomatoid or rhabdoid features (which are associated with advanced disease and poor prognosis) is rarely observed in the subtypes of renal cell carcinoma (RCC). The SWI/SNF chromatin-remodeling complex, which is composed of evolutionarily conserved core subunits including SMARCB1/INI1 (SMARCB1), SMARCA4/BRG1 (SMARCA4), SMARCC1/BAF155 (SMARCC1), and SMARCC2/BAF170 (SMARCC2), can be regarded as the prototype of an epigenetic regulator of gene expression that is involved in tumor suppression. We analyzed the histological, immunohistochemical, and clinicopathological status in 72 cases of RCC with sarcomatoid or rhabdoid features, focusing on the expression status of the subunits of SWI/SNF chromatin-remodeling complex proteins. Cases with lost or reduced expression were defined as showing aberrant expression. The frequency of aberrant SMARCA4 immunoexpression of a sarcomatoid or rhabdoid component in clear cell RCC (ccRCC) (47/50, 94%) was significantly higher than that in non-ccRCC (4/9, 44%) (p < 0.001). In ccRCC without sarcomatoid or rhabdoid features, aberrant SMARCA4 immunoexpression was observed in 33 of 48 (67%) cases. Immunoreactivities for SMARCB1, SMARCA2, and SMARCC2 were retained in almost all subtypes of RCC. The patients with aberrant SMARCA4 expression in RCC with sarcomatoid or rhabdoid features achieved shorter progression-free survival compared with the patients with retained SMARCA4 expression (all subtypes of RCC, p = 0.0212; ccRCC, p = 0.0265). These results suggest that in ccRCC, aberrant SMARCA4 expression is one of the adverse prognostic factors or a high-grade malignant transforming factor. The evaluation of SMARCA4 immunoexpression may be a useful diagnostic tool to help distinguish ccRCC from non-ccRCC.

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.

Impact of rhabdoid differentiation on postoperative outcome for patients with N0M0 renal cell carcinoma

BACKGROUND AND OBJECTIVE

We assessed the aggressiveness of localized renal cell carcinoma (N0M0 RCC) with rhabdoid differentiation (RD) after partial or radical nephrectomy.

METHODS

A total of 604 patients with N0M0 RCC who had undergone partial or radical nephrectomy at a single institution were included in this study. Clinicopathological and outcome data on recurrence-free survival (RFS), cancer-specific survival (CSS), and time to recurrence (TTR) were analyzed using Kaplan-Meier methods, log-rank test, univariate and multivariable Cox proportional hazard models, and concordance index. We also evaluated the RFS and CSS in a propensity score-matched cohort to reduce inherent differences. Among the 604 patients, RD was identified in RCC specimens from 24 patients.

RESULTS

At the median postoperative follow-up period of 53 months, 58 patients (12 with RD) showed recurrence and 26 patients (7 with RD) had died from RCC. Multivariate analyses showed that RD was an independent risk factor of RFS (hazard ratio 2.81; P = 0.0266) and CSS (hazard ratio 5.18; P = 0.00182). By RD adding to standard risk factors, the concordance indices for RFS and CSS increased 0.77 to 0.79, and 0.76 to 0.79, respectively. Subgroup analysis showed that the presence of RD in RCC specimens was more important for predicting poor RFS and CSS in the early pathological tumor category (≤pT2) subgroup compared to in the advanced tumor category (≥pT3) subgroup. Patients with RD showed a significantly shorter TTR than patients with RCC without RD (7.5 vs. 18 months: P = 0.0150). The propensity score-matched cohort included 24 patients with RD and 24 without RD, of which patients RD showed significantly shorter RFS than those without RD (P = 0.0026).

CONCLUSIONS

In summary, the aggressiveness of N0M0 RCC with RD increased the risk of postoperative recurrence, particularly in the early pathological stage. The short TTR also demonstrated the aggressiveness of RCC with RD.

Percentage grade 4 tumour predicts outcome for clear cell renal cell carcinoma

Heterogeneity of tumour grading is common in clear cell renal cell carcinoma (ccRCC). WHO/ISUP grading specifies that RCC should be graded based on the highest grade present in at least one high power field. This does not take into account the proportion of high grade tumour present in a cancer, which may itself influence outcome. Cases of ccRCC accessioned by Aquesta Uropathology, Brisbane, Australia, between 2008 and 2015, were reviewed and grading assigned according to WHO/ISUP criteria. For tumours classified as grade 3 (G3) and 4 (G4), the percentage of tumour showing G3 and G4 morphology was assessed for each case. Survival analysis, with time to the development of metastases as the clinical outcome, was performed for six grading subclasses (G3 <10%, G3 10-50%, G3 >50%, G4 <10%, G4 10-50%, G4 >50%). Of the 681 cases of ccRCC in the series, there were 153 cases classified as G3 (91 cases) and G4 (62 cases) for which follow-up was available. During the follow-up period of <1-89 months, 19 (20.9%) patients with G3 and 30 (48.3%) patients with G4 cancers developed metastatic disease. The three subgroups of <10%, 10-50% and >50% G3 tumour were not significant in predicting outcome (p=0.47). Separating G3 into two groups of ≤50% vs >50% was also not significantly associated with outcome (p=0.22). For the three subgroups of G4 ccRCC (<10%, 10-50% and >50% G4) a higher percentage of G4 correlated with time to the development of metastases (p=0.01). Even though G4 tumours as a whole had a significantly worse outcome than G3 tumours (p=0.0004), the difference between G4 <10% and G3 tumours was not significant (p=0.27). On multivariate analysis, that included pT staging category and tumour size, there was a significant difference in survival between G4<10% and G4>50% tumours (p=0.018). The results of the study suggest that for ccRCC, WHO/ISUP G4 category should incorporate the percentage of G4 tumour present.

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.