Metastatic Chromophobe Renal Cell Carcinoma: Presence or Absence of Sarcomatoid Differentiation Determines Clinical Course and Treatment Outcomes

Case report: Uncommon gastric metastasis as a presentation of recurrent clear cell renal cell carcinoma

Renal cell carcinoma (RCC) is a kidney neoplasm that accounts for 85% of cases and has complex genetic pathways that affect its development and progression. RCC metastasis can occur in 20%-50% of patients and usually affects distant organs. Gastric metastases (GM) from RCC are rare and present as polyp-like growths in the submucosal layer, accounting for 0.2%-0.7% of cases. This case report describes an 84-year-old female with Furhman grade II ccRCC who presented with an atherothrombotic ischemic stroke and gastrointestinal bleeding nine years post-radical nephrectomy. Gastroscopy revealed a 12mm pseudopedicled gastric lesion with ulceration and bleeding, diagnosed as metastatic ccRCC. The discussion focuses on the rarity, diagnostic challenges, and prognostic elements of gastric metastasis from RCC. The median survival after detecting digestive metastasis varies widely, and the mechanisms include direct invasion and dissemination through lymphatic, transcelomic, or hematogenous routes. Prognostic markers encompass patient history, symptoms, time since RCC diagnosis, overall health, and genetic factors. Surgical removal of gastric lesions and targeted therapy are treatment options that can improve survival. This case report highlights the need for further research to enhance diagnostic and treatment strategies for this rare aspect of RCC pathophysiology.

High-Grade, Nonsarcomatoid Chromophobe Renal Cell Carcinoma: A Series of 22 Cases With Novel Molecular Features on a Subset

Chromophobe renal cell carcinoma (ChRCC) is the third most common subtype of renal cell carcinoma and typically exhibits indolent behavior, though a rare subset can exhibit high-grade morphologic features and is associated with a poor prognosis. Although there are limited data on the molecular characteristics of metastatic and sarcomatoid ChRCC, the molecular features of high-grade, nonsarcomatoid ChRCC remain unexplored. Herein, we characterize 22 cases of ChRCC with high-grade, nonsarcomatoid components. High-grade ChRCC frequently demonstrated advanced stage at diagnosis (64% ≥pT3a or N1), with regions of extrarenal extension, nodal metastases, and vascular invasion consisting solely of high-grade ChRCC morphologically. We performed spatially guided panel-based DNA sequencing on 11 cases comparing high-grade and low-grade regions (n = 22 samples). We identified recurring somatic alterations emblematic of ChRCC, including deletions of chromosomes 1, 2, 6, 10, 13, 17, and 21 in 91% (10/11) of cases and recurring mutations in TP53 (81.8%, n = 9/11) and PTEN (36.4%, n = 4/11). Notably, although PTEN and TP53 alterations were found in both high-grade and low-grade regions, private mutations were identified in 3 cases, indicating convergent evolution. Finally, we identified recurring RB1 mutations in 27% (n = 3) of high-grade regions leading to selective protein loss by immunohistochemistry not observed in adjacent low-grade regions. This finding was confirmed in The Cancer Genome Atlas cohort where 2 of 66 cases contained RB1 mutations and demonstrated unequivocal high-grade, nonsarcomatoid morphology. We also detected multiple chromosomal gains confined to the high-grade regions, consistent with imbalanced chromosome duplication. These findings broaden our understanding of the molecular pathogenesis of ChRCC and suggest that subclonal RB1 mutations can drive the evolution to high-grade, nonsarcomatoid ChRCC.

Molecular underpinnings of dedifferentiation and aggressiveness in chromophobe renal cell carcinoma

Sarcomatoid dedifferentiation is common to multiple renal cell carcinoma (RCC) subtypes, including chromophobe RCC (ChRCC), and is associated with increased aggressiveness, resistance to targeted therapies, and heightened sensitivity to immunotherapy. To study ChRCC dedifferentiation, we performed multiregion integrated paired pathological and genomic analyses. Interestingly, ChRCC dedifferentiates not only into sarcomatoid but also into anaplastic and glandular subtypes, which are similarly associated with increased aggressiveness and metastases. Dedifferentiated ChRCC shows loss of epithelial markers, convergent gene expression, and whole genome duplication from a hypodiploid state characteristic of classic ChRCC. We identified an intermediate state with atypia and increased mitosis but preserved epithelial markers. Our data suggest that dedifferentiation is initiated by hemizygous mutation of TP53, which can be observed in differentiated areas, as well as mutation of PTEN. Notably, these mutations become homozygous with duplication of preexisting monosomes (i.e., chromosomes 17 and 10), which characterizes the transition to dedifferentiated ChRCC. Serving as potential biomarkers, dedifferentiated areas become accentuated by mTORC1 activation (phospho-S6) and p53 stabilization. Notably, dedifferentiated ChRCC share gene enrichment and pathway activation features with other sarcomatoid RCC, suggesting convergent evolutionary trajectories. This study expands our understanding of aggressive ChRCC, provides insight into molecular mechanisms of tumor progression, and informs pathologic classification and diagnostics.

External validation of a four-tiered grading system for chromophobe renal cell carcinoma

This study aimed to validate the prognostic value of a four-tiered grading system recently proposed by Avulova et al. and to explore the prognostic ability of another four-tiered classification grading system in which there is a separate Grade 3 for tumor necrosis. Grading of chromophobe renal cell carcinoma (ChRCC) by the Fuhrman system is not feasible because of the inherent nuclear atypia in ChRCC. We collected relevant data of 263 patients with ChRCC who had undergone surgery in our hospital from 2008 to 2020. The Kaplan-Meier method was used to calculate the survival rate and Cox proportional hazard regression models to assess associations with cancer-specific survival and distant metastasis-free survival by hazard ratios (HRs) and 95% confidence intervals (CIs). Ten patients died from ChRCC, and 12 developed metastases. The 5 year CSS rates were 95.9%. Grades 2 (HR = 10.9; CI 1.11-106.4; P = 0.04), 3 (HR = 33.6, CI 3.32-339.1; P = 0.003), and 4 (HR = 417.4, CI 35.0-4976.2; P < 0.001) in a four-tiered grading system were significantly associated with CSS in a multivariate setting. However, the difference in CSS between Grades 2 and 3 was not significant (HR = 2.14, 95% CI 0.43-10.63; P = 0.35). The HRs of the associations between an exploratory grading system that includes a separate Grade 3 for tumor necrosis and CSS were as follows: Grade 2, 10.2 (CI 1.06-97.9, P = 0.045); Grade 3, 11.4 (CI 1.18-109.6, P = 0.04); and Grade 4, 267.9 (CI 27.6-2603.3, P < 0.001). Similarly, Grades 2 and 3 did not differ significantly. The four-tiered grading system studied is useful for predicting death from ChRCC and metastasis. However, Grade 3 did not more accurately predict risk of death and metastasis than did Grade 2. This was also true for the novel exploratory grading system that classifies tumors with necrosis into a separate Grade 3.

Sintilimab combined with axitinib in the treatment of advanced chromophobe renal cell carcinoma: a case report

Chromophobe renal cell carcinoma (ChRCC) is a rare pathological type of renal cell carcinoma (RCC). Related systematic studies involving large numbers of patients are lacking, and more importantly, there is currently no international consensus on post-line treatment guidelines for ChRCC. The rapid development of systemic treatment with molecular targeted therapies and immune checkpoint inhibitors has brought effective approaches for patients with clear cell renal cell carcinoma (ccRCC), while progress in the treatment of ChRCC is still limited. In this case report, the patient was initially diagnosed at the early stage; 4 years post-surgery, she developed lung metastases and the disease progressed once again after being treated with sunitinib monotherapy for 3 years. However, after combining the immunotherapy sintilimab with the targeted therapy axitinib as second-line treatment, imageological examination showed lesions in the lungs that gradually decreased, and the bone metastases remained stable. To date, the patient has been continuously treated for over 2 years and is still undergoing regular treatment and follow-up. This case is the first to report the long-term survival of metastatic disease by using this treatment regimen and to propose a potential therapeutic option for patients with metastatic ChRCC. Since only one case was observed in this report, further study is needed.

Chromophobe Renal Cell Carcinoma with Sarcomatoid Differentiation: Clinicopathologic Correlation and Molecular Findings

Introduction: Sarcomatoid differentiation has been reported in approximately 8% of chromophobe renal cell carcinoma (RCC) and is associated with a worse prognosis. We aim to describe the clinicopathologic and molecular findings of chromophobe RCC with sarcomatoid differentiation. Methods: Surgical pathology database was searched to identify chromophobe RCC with sarcomatoid differentiation from January 2015 to December 2021. Results: Five patients were diagnosed with chromophobe RCC with sarcomatoid differentiation. The median age at the time of diagnosis was 57 years (range 51-61 years). Three patients died after median follow-up of 12.1 months (range 1.6-18.2 months). The median tumor size was 10.7 cm (range 5.6-13.6 cm). The median percentage of sarcomatoid component was 60% (range 10-90%), and the median percentage of necrosis was 30% (range 10-50%). One tumor demonstrated osteoid formation. PAX8, keratin 7, KIT (CD117), and Hale colloidal iron were positive in the epithelial component, whereas the sarcomatoid component was positive for vimentin, CD10, and high Ki67 proliferative index. Molecular testing was performed in three specimens: all were TP53 mutated and microsatellite stable. One aggressive tumor had RB1 frameshift mutation and copy number gains for TERT and CUL4A. Conclusion: Chromophobe RCC with sarcomatoid differentiation is a rare entity with aggressive behavior. Percentage of sarcomatoid component, necrosis, and the occurrence of metastasis is associated with worse prognosis. Molecular profiling reveals frequent TP53 mutation. While TERT promoter mutation has no prognostic implication, FLCN inactivation may be associated with a less aggressive course. The clinical significance of RB1 loss is unclear.

Genetic Profiling Uncovers Genome-Wide Loss of Heterozygosity and Provides Insight into Mechanisms of Sarcomatoid Transformation in Chromophobe Renal Cell Carcinoma

Sarcomatoid transformation occurs in ∼8% of chromophobe renal cell carcinoma (chRCC) and is associated with aggressive clinical behavior. In recent years, several studies have identified genomic, transcriptomic, and epigenomic correlates of aggressive behavior in chRCC; however, the molecular mechanisms associated with sarcomatoid transformation remain incompletely understood. In this study, we analyzed paired conventional and sarcomatoid histologic components of individual chRCC to elucidate the genomic alterations that underlie sarcomatoid transformation in this tumor type. Massively parallel sequencing was performed on paired (conventional and sarcomatoid) components from 8 chRCCs. All cases harbored TP53 variants (87.5% showing TP53 variants in both components and 12.5% only in the sarcomatoid component). Intratumor comparisons revealed that TP53 variants were concordant in 71% and discordant in 29% of cases. Additional recurrent single-nucleotide variants were found in RB1 (37.5% of cases) and PTEN (25% of cases), with the remaining single-nucleotide variants detected in these tumors (PBRM1, NF1, and ASXL1) being nonrecurrent. Copy number variant analysis showed the characteristic pattern of chromosomal losses associated with chRCC (1, 2, 6, 10, 13, 17, and 21) in the conventional histologic components only. Interestingly, the sarcomatoid components of these tumors demonstrated widespread loss of heterozygosity but lacked the above chromosomal losses, likely as a consequence of whole-genome duplication/imbalanced chromosomal duplication events. Overall, the findings suggest that TP53 variants followed by whole-genome duplication/imbalanced chromosomal duplication events underlie sarcomatoid transformation in chRCC.

The incidence, pathogenesis, and management of non-clear cell renal cell carcinoma

Renal cell carcinoma (RCC) is the most common type of kidney cancer and is divided into two distinct subtypes, clear cell renal cell carcinoma (ccRCC) and non-clear cell renal cell carcinoma (nccRCC). Although many treatments exist for RCC, these are largely based on clinical trials performed in ccRCC and there are limited studies on the management of nccRCC. Non-clear cell RCC consists of multiple histological subtypes: papillary, chromophobe, translocation, medullary, collecting duct, unclassified, and other rare histologies. Due to variations in pathogenesis and therapeutic response, therapy should be tailored to specific variant histologies. For patients with localized nccRCC, surgical resection remains the gold standard. In the metastatic setting, the standard of care has yet to be clearly defined, and most guidelines recommend clinical trial participation. General therapeutic options include immunotherapy, either as monotherapy or in combination, targeted therapies such as vascular endothelial growth factor tyrosine kinase inhibitors and MET inhibitors, and chemotherapy in certain subtypes. Here we present a review of the incidence and pathogenesis of the various subtypes, as well as available clinical data to support therapeutic recommendations for these subtypes. We also highlight currently available clinical trials in nccRCC and future directions in investigating novel treatment modalities tailored to patients with variant histology.

Common clinicopathological and immunological features of sarcomatoid carcinoma across organs: A histomorphology-based cross-organ study

Sarcomatoid carcinoma (SC), which can occur in any organ, is a rare disease. To elucidate common characteristics of SC beyond organs, we evaluated clinicopathological and immunological features of SC defined by the single histological criterion beyond organs compared to randomly matched conventional carcinoma (non-SC) adjusted for the disease stage. Immunological features were assessed by multiplex immunohistochemistry, comparing immune cell density in tumor tissues and tumor programmed death-ligand 1 (PD-L1) expression. A total of 101 patients with SC or non-SC (31 lung, 19 esophagus, 22 pancreas, 15 liver, 4 bile duct, 6 kidney, 2 uterus and 2 ovary) were identified among 7197 patients who underwent surgery at our institute (1997-2020). SC was significantly associated with worse survival (HR: 1.571; 95% CI: 1.084-2.277; P = .017). The frequency of postoperative progression within 6 months was significantly higher for SC patients (54% vs 28%; P = .002). The immune profiling revealed the densities of CD8+ T cells (130 vs 72 cells/mm2 ; P = .004) and tumor-associated macrophages (566 vs 413 cells/mm2 ; P < .0001) and the tumor PD-L1 expression score (40% vs 5%; P < .0001) were significantly higher in SCs than in non-SCs. Among 73 SC patients with postoperative progression, multivariate Cox regression analysis showed that immunotherapy tended to be associated with favorable survival (HR: 0.256; 95% CI: 0.062-1.057; P = .060). Collectively, SCs shared clinicopathological and immunological features across organs. Our study can initiate to standardize the pathological definition of SC and provide a rationale for the investigation and development for this rare disease in a cross-organ manner.

Renal Cell Carcinoma of Variant Histology: Biology and Therapies

The term variant histology renal cell carcinomas (vhRCCs), also known as non-clear cell RCCs, refers to a diverse group of malignancies with distinct biologic and therapeutic considerations. The management of vhRCC subtypes is often based on extrapolating results from the more common clear cell RCC studies or basket trials that are not specific to each histology. The unique management of each vhRCC subtype necessitates accurate pathologic diagnosis and dedicated research efforts. Herein, we discuss tailored recommendations for each vhRCC histology informed by ongoing research and clinical experience.

Characterization of Intercalated Cell Markers KIT and LINC01187 in Chromophobe Renal Cell Carcinoma and Other Renal Neoplasms

Introduction. Chromophobe renal cell carcinoma (chromophobe RCC) is the third major subcategory of renal tumors after clear cell RCC and papillary RCC, accounting for approximately 5% of all RCC subtypes. Other oncocytic neoplasms seen commonly in surgical pathology practice include the eosinophilic variant of chromophobe RCC, renal oncocytoma, and low-grade oncocytic unclassified RCC. Methods. In our recent next-generation sequencing based study, we nominated a lineage-specific novel biomarker LINC01187 (long intergenic non-protein coding RNA 1187) which was found to be enriched in chromophobe RCC. Like KIT (cluster of differentiation 117; CD117), a clinically utilized chromophobe RCC related biomarker, LINC01187 is expressed in intercalated cells of the nephron. In this follow-up study, we performed KIT immunohistochemistry and LINC01187 RNA in situ hybridization (RNA-ISH) on a cohort of chromophobe RCC and other renal neoplasms, characterized the expression patterns, and quantified the expression signals of the two biomarkers in both primary and metastatic settings. Results. LINC01187, in comparison to KIT, exhibits stronger and more uniform expression within tumors while maintaining temporal and spatial consistency. LINC01187 also is devoid of intra-tumoral heterogeneous expression pattern, a phenomenon commonly noted with KIT. Conclusions. LINC01187 expression can augment the currently utilized KIT assay and help facilitate easy microscopic analyses in routine surgical pathology practice.

The role of immunotherapy in non-clear cell renal cell carcinoma

The category of non-clear cell renal cell carcinoma (nccRCC) includes several clinically, histologically, and molecularly diverse entities. Traditionally, they comprise type 1 and type 2 papillary, chromophobe, unclassified, and other histologies (medullary, collecting duct carcinoma, and translocation-associated). Molecular knowledge has allowed the identification of some other specific subtypes, such as fumarate hydratase-deficient renal cell carcinoma (RCC) or succinate dehydrogenase-associated RCC. In addition, it has recognized some alterations with a possible predictive role, e.g., MET proto-oncogene receptor tyrosine kinase (MET) alterations in papillary tumors. Standard therapies for the management of advanced clear cell RCC (ccRCC), i.e., vascular endothelial growth factor receptor (VEGFR) pathway inhibitors and mammalian target of rapamycin inhibitors, have shown poorer results in nccRCC patients. Therefore, there is a need to improve the efficacy of the treatment for advanced nccRCC. Immunotherapy, especially immune checkpoint inhibitors (ICIs) targeting programmed death 1/programmed death ligand 1 and cytotoxic T-lymphocyte associated protein 4 (CTLA-4), has demonstrated a significant survival benefit in several malignant neoplasias, including ccRCC, with a proportion of patients achieving long survival. The combinations of ICI or ICI + VEGFR tyrosine kinase inhibitors (TKIs) are the standard of care in advanced ccRCC. Unfortunately, major pivotal trials did not include specific nccRCC populations. In recent years, several studies have retrospectively or prospectively evaluated ICIs alone or in combination with another ICI or with TKIs in nccRCC patients. In this article, we review data from available trials in order to elucidate clinical and molecular profiles that could benefit from immunotherapy approaches.

The Critical Gene Screening to Prevent Chromophobe Cell Renal Carcinoma Metastasis through TCGA and WGCNA

Common chromophobe renal cell carcinoma (chRCC) has a good prognosis when cured by surgery. However, clinical practice shows that a small number of patients with chRCC will produce metastasis, and the prognosis after metastasis is poor. In this regard, we try to find potential biological targets to prevent CRCC metastasis. In this experiment, we analyzed the clinical traits and gene expression data of chRCC samples which were provided by the TCGA database by the WGCNA method. On this basis, we selected MEtan, a module with a significant positive correlation with the M phase of chRCC, for subsequent analysis. The MEtan module genes in the biological process of chRCC were mainly related to steroid metabolic process, cholesterol metabolic process and STEM cell differentiation. KEGG analysis showed that these genes were mainly enriched in cancer-related signaling pathways, such as Neuroactive Ligand−receptor interaction, cAMP signaling pathway, and Wnt signaling pathway. Subsequently, we mapped the PPI interaction network and screened the key gene beta-arrestin 2 (ARRB2). Expression analysis showed that there was a significantly increased expression of ARRB2 in chRCC patients in comparison to the normal group. Expression survival analysis indicated that ARRB2 was inversely associated with overall survival. We firmly believe that the key genes identified in this study would be able to provide new clues and research basis for the treatment of chRCC.

Two case reports of immune checkpoint therapy on chromophobe renal cell carcinoma with sarcomatoid differentiation

Renal cell carcinoma (RCC) is the most predominant type of kidney cancer in adults and comprises several histological subtypes. Among them, the chromophobe RCC (ChRCC) with sarcomatoid differentiation is a rare subtype, and its therapeutic strategy remains unclear. Hence, to provide more information on effective therapeutic strategies against ChRCC, we report two cases of ChRCC with sarcomatoid differentiation treated with nivolumab monotherapy or ipilimumab-nivolumab combination therapy. One patient was treated with nivolumab monotherapy after the failure of sunitinib, while the other was treated with ipilimumab-nivolumab combination therapy as a first-line option. The therapeutic strategies adopted in both cases were effective, but the patients experienced immune-related adverse events such as interstitial nephritis and colitis. Thus, our report indicates that immune checkpoint therapy is effective for ChRCCs with sarcomatoid differentiation.

The Histologic Diversity of Chromophobe Renal Cell Carcinoma With Emphasis on Challenges Encountered in Daily Practice

Chromophobe renal cell carcinoma (ChRCC) is the third most common renal cell carcinoma in adults. The aim of this review is to provide a comprehensive overview highlighting the broad morphologic spectrum of ChRCC, and offer a practical approach for handling cases in daily practice. For the purpose of this review, we classify ChRCC subtypes as (1) classic, (2) eosinophilic, (3) sarcomatoid, and (4) other rare patterns. The concept of eosinophilic ChRCC has significantly evolved, yet it still is one of the major diagnostic challenges pathologists face in routine practice due to its morphologic overlap with renal oncocytoma. Rare patterns of ChRCC have been described over the last few decades, showing a wide histologic spectrum including those with adenomatoid microcystic pigmented, multicystic, neuroendocrine, small cell, and papillary features. ChRCC represents a heterogenous group of neoplasms, demonstrating varied but unique morphologic and genetic profiles. Although the field of ChRCC knowledge is still evolving, rare patterns can present diagnostic challenges if they are not known to pathologists and/or clinicians. Proper and generous tumor sampling along with careful histologic examination allow for recognition of these rare morphologies. The role of routine molecular testing appears to be limited. From a clinical management standpoint, the rare patterns of ChRCC seem to have no definite clinical implications at present and likely can be managed similarly to usual ChRCC. Finally, we will discuss distinctive novel/emerging renal neoplasms previously considered under the spectrum of ChRCC, low-grade oncocytic renal tumor and eosinophilic vacuolated tumor, with regard to their current significance and implications for future classification strategies.

Clinicopathologic and Immunohistochemical Characterization of Sarcomatoid Chromophobe Renal Cell Carcinoma: An Analysis of 22 Cases

Sarcomatoid differentiation in chromophobe renal cell carcinoma (ChRCC) is a rare finding and a significant predictor of worse outcomes. When the sarcomatoid component overgrows the conventional component or is the only component on a biopsy, the differential diagnoses encompass a variety of entities. Therefore, we reviewed 22 sarcomatoid ChRCCs and characterized the immunophenotype. Given that renal carcinomas with sarcomatoid features may benefit from immune checkpoint inhibitor-based therapy we also assessed the programmed death-ligand 1 (PD-L1) (28-8) expression. DOG1, CD117, cytokeratin 7, and PAX8 were negative in 100%, 88%, 63%, and 44% of the sarcomatoid components, respectively. GATA3 was expressed in 31% of the conventional components and in 50% of the sarcomatoid components. One conventional and 3 sarcomatoid components expressed PD-L1. Sarcomatoid ChRCCs have a high propensity for metastases and cancer progression. Distant metastatic disease was seen in 73% of the cases and median survival in this cohort was <1 year. The sarcomatoid portion had increased expression of PD-L1 and frequent loss of expression of multiple immunohistochemical markers associated with ChRCC. Half of the sarcomatoid ChRCC exhibited GATA3 expression, 3 of which did not express PAX8.

MALDI Mass Spectrometry Imaging-Prognostic Pathways and Metabolites for Renal Cell Carcinomas

Simple Summary

Renal cell carcinoma (RCC) is the seventh most common cancer type and accounts for more than 80% of all renal tumors. Nevertheless, prognostic biomarkers for RCC are still missing. Therefore, we analyzed a large, multicenter cohort including the three most common RCC subtypes (clear cell RCC (ccRCC), papillary RCC (pRCC) and chromophobe RCC (chRCC)) by high mass resolution matrix-assisted laser desorption/ionization (MALDI) mass spectrometry imaging (MSI) for prognostic biomarker detection. This is a suitable method for biomarker detection for several tumor entities. We detected several pathways and metabolites with prognostic power for RCC in general and also for different RCC subtypes.

Abstract

High mass resolution matrix-assisted laser desorption/ionization (MALDI) mass spectrometry imaging (MSI) is a suitable method for biomarker detection for several tumor entities. Renal cell carcinoma (RCC) is the seventh most common cancer type and accounts for more than 80% of all renal tumors. Prognostic biomarkers for RCC are still missing. Therefore, we analyzed a large, multicenter cohort including the three most common RCC subtypes (clear cell RCC (ccRCC), papillary RCC (pRCC) and chromophobe RCC (chRCC)) by MALDI for prognostic biomarker detection. MALDI-Fourier-transform ion cyclotron resonance (FT-ICR)-MSI analysis was performed for renal carcinoma tissue sections from 782 patients. SPACiAL pipeline was integrated for automated co-registration of histological and molecular features. Kaplan–Meier analyses with overall survival as endpoint were executed to determine the metabolic features associated with clinical outcome. We detected several pathways and metabolites with prognostic power for RCC in general and also for different RCC subtypes.

Treatment and Outcome of Metastatic Renal Cell Carcinoma With Sarcomatoid Differentiation: A Single-Center, Real-World Analysis of Retrospective Data

Background: Sarcomatoid differentiation/histology of renal cell carcinoma (sRCC) in patients with metastatic renal cell carcinoma (mRCC) is still underresearched in current therapy regimes. We aimed to evaluate the impact of sRCC on outcomes in patients with mRCC treated with tyrosine kinase inhibitors (TKIs).

Methods: We collected complete data of 262 consecutive mRCC patients from our institutional database for this retrospective study. All patients were treated with TKIs within a single or multimodal treatment approach. All analyses were adjusted for the presence of sRCC. Descriptive statistics as well as uni- and multivariable outcome metrics, including progression-free (PFS) and overall survival (OS) as endpoints were performed.

Results: Overall, 18 patients had sRCC (6.9%). Patients with sRCC had more often clear-cell histology (p = 0.047), a higher T-stage (p = 0.048), and underwent cytoreductive nephrectomy more frequently (p < 0.001). The most common first-line TKIs were Sunitinib (65.6%), Sorafenib (19.5%), and Pazopanib (10.3%), respectively. At a median follow-up of 32 months, patients with sRCC had significantly reduced PFS (p = 0.02) and OS (p = 0.01) compared to patients without sRCC. In multivariable analyses that adjusted for the effects of standard mRCC predictors, the sarcomatoid feature retained its independent association with inferior PFS (HR: 2.39; p = 0.007) and OS (HR: 2.37; p = 0.001). This association remained statistically significant in subgroup analyses of patients with Sunitinib as first-line therapy (PFS p < 0.001; OS: p < 0.001).

Conclusion: Despite its rare occurrence, our findings confirm sRCC as a powerful predictor for inferior outcomes in mRCC treated with targeted therapies. This suggests a need for more tailored treatment strategies in patients harboring mRCC with sarcomatoid histology to improve oncological outcomes.

Durable Remission with Immunotherapy in a Patient with Sarcomatoid Renal Cell Carcinoma

Sarcomatoid differentiation is a rare and aggressive histologic subtype with poor prognosis, seen in several malignancies. In sarcomatoid renal cell carcinoma (RCC), the degree of sarcomatoid differentiation and the stage at presentation determines the prognosis. Despite resection, chemotherapy and targeted therapy response is modest, with relapse usually occurring within a few months. We present a case of a gentleman with sarcomatoid RCC managed with pembrolizumab, who has had no evidence of recurrence for over 4 years since the last dose of immunotherapy. RCCs with sarcomatoid differentiation have a high presence of programmed cell death protein 1 and programmed cell death ligand 1 in T cells and tumor cells, respectively, making immunotherapy an attractive option in this setting. Clinical trials are ongoing to further define the benefit of immunotherapy in sarcomatoid RCC.

An up-to-date evaluation of cabozantinib for the treatment of renal cell carcinoma

Introduction: In the evolving treatment scenario of metastatic renal cell carcinoma, cabozantinib is gaining increasing attention, presenting as a cornerstone therapy, both as a monotherapy and in combination with immune-checkpoint inhibitors.Areas covered: In this review, the authors explore the role of cabozantinib in the treatment of metastatic clear cell and non-clear cell renal cell carcinoma, presenting data from the most recent clinical trials and investigating ongoing studies. They, furthermore, evaluate the pharmacokinetic, pharmacodynamic, and immunomodulatory effect of cabozantinib, as well as underlining the tolerability profile and patients' quality of life.Expert opinion: Cabozantinib's administration as a single agent is restricted to intermediate- and poor-risk patients (according to IMDC criteria). The further advent of anti-VEGF-receptor tyrosine kinase inhibitors combined with immune checkpoint inhibitor regimens (such as pembrolizumab + axitinib) has allowed to expand the use of cabozantinib, leading to its combination with nivolumab. In the next few years, more information is required to look for the application of cabozantinib-based combinations as a later-line approach in metastatic RCC patients, beside their use in the first-line setting.

Sarcomatoid features and lymph node-positive disease in chromophobe renal cell carcinoma

PURPOSE

The presence of sarcomatoid features and/or lymph node-positive disease may be associated with a worse prognosis in chromophobe renal cell carcinoma (ChRCC). We sought to better characterize patients' long-term outcomes with these features compared with those without these features.

MATERIALS AND METHODS

We identified 300 patients treated for sporadic, unilateral, nonmetastatic ChRCC between 1993 and 2019. Clinical and pathologic features were summarized, and cancer-specific survival (CSS) and recurrence-free survival (RFS) were analyzed using Kaplan-Meier plots. Cox regression analysis was performed to determine factors associated with recurrence. Patients with sarcomatoid features and/or nodal disease were grouped as high-risk in a secondary analysis.

RESULTS

The median age was 60 years, 43.7% were female, 29.3% had pT3/T4 disease, 3.3% had sarcomatoid features, and 4% had pathologic N1 disease. Sixteen patients were categorized as high-risk based on the presence of sarcomatoid features (n = 4), pathologic N1 disease (n = 6), or both (n = 6). There were 22 recurrences; the recurrence rate in the low-risk group was 4.9% and 50% in the high-risk group. 10-year RFS was 91.4% in the low-risk group and 34.4% in the high-risk group (P < 0.001). 10-year CSS was 96.4% in the low-risk group and 54.3% in the high-risk group (P < 0.001). In multivariable analysis, sarcomatoid features (HR 5.5, CI 1.5-20.2, P = 0.01) and pN1 disease (HR 16.5, CI 5.3-51.4, P < 0.0001) were independently associated with RFS.

CONCLUSIONS

The presence of sarcomatoid features and/or lymph node-positive disease portends a poor prognosis in ChRCC. Further studies evaluating the impact of novel therapeutic agents in these patients are warranted.

New developments in existing WHO entities and evolving molecular concepts: The Genitourinary Pathology Society (GUPS) update on renal neoplasia

The Genitourinary Pathology Society (GUPS) reviewed recent advances in renal neoplasia, particularly post-2016 World Health Organization (WHO) classification, to provide an update on existing entities, including diagnostic criteria, molecular correlates, and updated nomenclature. Key prognostic features for clear cell renal cell carcinoma (RCC) remain WHO/ISUP grade, AJCC/pTNM stage, coagulative necrosis, and rhabdoid and sarcomatoid differentiation. Accrual of subclonal genetic alterations in clear cell RCC including SETD2, PBRM1, BAP1, loss of chromosome 14q and 9p are associated with variable prognosis, patterns of metastasis, and vulnerability to therapies. Recent National Comprehensive Cancer Network (NCCN) guidelines increasingly adopt immunotherapeutic agents in advanced RCC, including RCC with rhabdoid and sarcomatoid changes. Papillary RCC subtyping is no longer recommended, as WHO/ISUP grade and tumor architecture better predict outcome. New papillary RCC variants/patterns include biphasic, solid, Warthin-like, and papillary renal neoplasm with reverse polarity. For tumors with 'borderline' features between oncocytoma and chromophobe RCC, a term "oncocytic renal neoplasm of low malignant potential, not further classified" is proposed. Clear cell papillary RCC may warrant reclassification as a tumor of low malignant potential. Tubulocystic RCC should only be diagnosed when morphologically pure. MiTF family translocation RCCs exhibit varied morphologic patterns and fusion partners. TFEB-amplified RCC occurs in older patients and is associated with more aggressive behavior. Acquired cystic disease (ACD) RCC-like cysts are likely precursors of ACD-RCC. The diagnosis of renal medullary carcinoma requires a negative SMARCB1 (INI-1) expression and sickle cell trait/disease. Mucinous tubular and spindle cell carcinoma (MTSCC) can be distinguished from papillary RCC with overlapping morphology by losses of chromosomes 1, 4, 6, 8, 9, 13, 14, 15, and 22. MTSCC with adverse histologic features shows frequent CDKN2A/2B (9p) deletions. BRAF mutations unify the metanephric family of tumors. The term "fumarate hydratase deficient RCC" ("FH-deficient RCC") is preferred over "hereditary leiomyomatosis and RCC syndrome-associated RCC". A low threshold for FH, 2SC, and SDHB immunohistochemistry is recommended in difficult to classify RCCs, particularly those with eosinophilic morphology, occurring in younger patients. Current evidence does not support existence of a unique tumor subtype occurring after chemotherapy/radiation in early childhood.

The Molecular Characteristics of Non-Clear Cell Renal Cell Carcinoma: What's the Story Morning Glory?

Non-clear cell renal cell carcinomas are a miscellaneous group of tumors that include different histological subtypes, each one characterized by peculiarity in terms of genetic alteration, clinical behavior, prognosis, and treatment response. Because of their low incidence and poor enrollment in clinical trials, alongside their heterogeneity, additional efforts are required to better unveil the pathogenetic mechanisms and, consequently, to improve the treatment algorithm. Nowadays, tyrosine kinase inhibitors, mTOR and MET inhibitors, and even cisplatin-based chemotherapy and immunotherapy are potential weapons that are still under evaluation in this setting. Various biomarkers have been evaluated for detecting progression and monitoring renal cell carcinoma, but more studies are necessary to improve this field. In this review, we provide an overview on the molecular characteristics of this group of tumors and the recently published trials, giving an insight into what might become the future therapeutic standard in this complex world of non-clear cell kidney cancers.

A challenging frontier - the genomics and therapeutics of nonclear cell renal cell carcinoma

PURPOSE OF REVIEW

As molecular profiling of renal cell carcinoma (RCC) continues to elucidate novel targets for nonclear cell histologies, understanding the landscape of these targets is of utmost importance. In this review, we highlight the genomic landscape of nonclear cell RCC and its implications for current and future systemic therapies.

RECENT FINDINGS

Several genomic studies have described the mutational burden among nonclear cell histologies. These studies have highlighted the importance of MET in papillary RCC and led to several clinical trials evaluating the efficacy of MET inhibitors for papillary RCC. The success of immune checkpoint inhibitors, such as ipilimumab and nivolumab, in clear cell RCC has led to ongoing trials evaluating these novel therapeutics in nonclear cell RCC.

SUMMARY

Genomic profiling has allowed for the evaluation of novel targets for nonclear cell RCC. This evolving therapeutic landscape is being explored in promising, ongoing trials that have the potential for changing how nonclear cell RCC is managed.

Non-clear cell renal carcinomas: Review of new molecular insights and recent clinical data

Non-clear cell renal cell carcinomas (nccRCC) represent a highly heterogeneous group of kidney tumors, consisting of the following subtypes: papillary carcinomas, chromophobe renal cell carcinoma, so-called unclassified carcinomas or aggressive uncommon carcinomas such as Bellini carcinoma, renal cell carcinoma (RCC) with ALK rearrangement or fumarate hydratase-deficient RCC. Although non-clear cell cancers account for only 15 to 30% of renal tumors, they are often misclassified and accurate diagnosis continues to be an issue in clinical practice. Current therapeutic strategy of metastatic nccRCC is based primarily on guidelines established for clear cell tumors, the most common subtype, however this approach remains poorly defined. To date, published clinical trials for all histological nccRCC subtypes have been collectively characterized into one group, in contrast to clear cell RCC, and given the small numbers of cases, the interpretation of study results continues to be challenging. This review summarizes the available literature for each nccRCC subtype and highlights the lack of supportive evidence from prospective clinical trials and retrospective studies. Future trials should evaluate treatment approaches which focus on a specific histological subtype and progress in treating nccRCC will be contingent on understanding the unique biology of their individual histologies.

Systemic Therapies for the Management of Non-Clear Cell Renal Cell Carcinoma: What Works, What Doesn't, and What the Future Holds

Non-clear cell renal cell carcinoma (nccRCC) is a broad term that refers to a diverse group of tumors, each with its own distinct biologic and therapeutic profile. The management of nccRCCs is often based on extrapolating data from clinical trials in the more common clear cell renal cell carcinoma, but our emerging prospective and retrospective clinical experience in nccRCC allows us to make more precise recommendations tailored to each histology. The systemic therapy options for metastatic nccRCC include targeted therapies such as tyrosine kinase inhibitors, immune checkpoint inhibitors, and, for specific rare subtypes, cytotoxic chemotherapy. Each nccRCC histology may respond differently to these regimens, which makes accurate pathologic diagnosis imperative. In the present review, we discuss the available clinical and biological data that can help guide systemic therapy recommendations for specific nccRCC subtypes.

Comprehensive review of chromophobe renal cell carcinoma

Chromophobe renal cell carcinoma (chRCC) is the third most common type of RCC with distinct biology compared to other kidney cancer subtypes. The heterogeneity between the RCC subtypes is associated with noticeable differences in tumor aggressiveness and risk for the development of metastatic disease. ChRCC is characterized by chromosomal aneuploidy, TP53, PTEN, and mitochondrial gene mutations. Though the therapeutic landscape of clear cell RCC (ccRCC) has significantly evolved over the past decade, limited progress has been seen in chRCC due to its infrequent incidence. In fact, the therapeutic approach for chRCC is often extrapolated from ccRCC treatments or studies that combine several forms of nccRCC subtypes. In the new era of genetic profiling of tumors and targeted therapeutics, this review describes the epidemiology, pathology, molecular characteristics, and current management with ongoing clinical trials for chRCC.

Dissecting Outcomes: Should Cytoreductive Nephrectomy Be Performed for Patients With Metastatic Renal Cell Carcinoma With Sarcomatoid Dedifferentiation?

Background

It is highly contested whether cytoreductive nephrectomy for treating advanced renal cell carcinoma (RCC) with sarcomatoid features (sRCC) benefits overall survival. Patients with sRCC are known to have a poor prognosis, and these tumors have a more aggressive biology than those without sarcomatoid features.

Methods

Patients with clear cell RCC or non–clear cell RCC underwent cytoreductive nephrectomy in efforts to improve overall survival (OS). Patients were stratified by presence or absence of histologic sarcomatoid features within tumor samples.

Results

Of 167 patients who underwent cytoreductive nephrectomy, 127 had clear cell RCC, of whom 14 had sarcomatoid features, and 40 had non–clear cell RCC, of whom 13 had sarcomatoid features. Median age of the cohort was 62 years (range, 56.5–69 years). The cohort included 119 male (71.3%) and 48 (28.7%) female patients. Among all patients with advanced RCC, having sRCC had a significantly worse OS after cytoreductive nephrectomy (30 vs 8 months; hazard ratio [HR], 2.88; P <0.0001). Additionally, favorable-risk patients had significantly longer OS compared to intermediate- or poor-risk patients (56 vs 30 vs 10 months; HR, 0.21; P =0.00016). For patients with clear cell RCC, having sRCC conferred a significantly poorer survival (30 vs 9 months; HR, 2.82; P=0.0035). Patients with non–clear cell sRCC also had significantly worse outcomes compared to patients whose tumors did not have sarcomatoid features (30 vs 6.5 months; HR, 3; P =0.009). When patients with sRCC were stratified by whether there was >10% or ≤10% sarcomatoid features present within the sample, there was no significant difference in OS (8 vs 8.5 months; P =0.32).

Conclusions

Sarcomatoid features within tumor histology confer significantly poor prognosis. Patients with sRCC, regardless of clear cell vs non–clear cell histology, have significantly shorter OS. Even among patients with 10% or less sarcomatoid features, there was no OS benefit to cytoreductive nephrectomy. Based on our findings, there appears to be a limited to no role of cytoreductive nephrectomy if sRCC is identified on pretreatment biopsy. The role of radiomics and pre-operative biopsies may confer significant benefit in this patient population.

Broad spectrum mutational analysis of chromophobe renal cell carcinoma using next-generation sequencing

BACKGROUND

Chromophobe renal cell carcinoma (ChRCC) is a rare subtype of non-clear cell renal cell carcinoma. Due to its rarity, its molecular characterization as well as therapeutic targets are still not fully understood.

METHODS

We performed a next-generation sequencing analysis using the platform Ion PGM System on 20 retrospectively collected ChRCC cases with the aim of identify molecular biomarkers with potential prognostic value or that could have therapeutic implications.

RESULTS

We identified mutation onTP53, SMARCB1, RB1 and JAK3. The most frequently altered gene was TP53 (6/20, 30 % of cases). SMARCB1 mutation was found in 3 (15 %) patients and in all cases the mutational variant was p.T72 K, with known pathogenenic meaning. One (5%) patient presented a pathogenetic mutation of RB1. JAK3 was mutated in 1 (5%) patient and this mutation resulted to have uncertain pathogenetic significance.

CONCLUSION

ChRCC is a rare disease still not fully molecularly characterized. Next-generation sequencing analysis could be useful to identify potential mutation with prognostic value or that could be potential therapeutic targets.

Evaluation of Clear Cell, Papillary, and Chromophobe Renal Cell Carcinoma Metastasis Sites and Association With Survival

IMPORTANCE

There exists considerable biological and clinical variability between histologic variants of metastatic renal cell carcinoma (mRCC). Data reporting on patterns of metastasis in histologic variants of mRCC are sparse.

OBJECTIVE

To characterize sites of metastasis and their association with survival across the 3 most common histologic variants of mRCC: clear cell (ccRCC), papillary (pRCC), and chromophobe (chrRCC).

DESIGN, SETTING, AND PARTICIPANTS

In this multicenter, international cohort study, the International mRCC Database Consortium (IMDC) database was used to identify consecutive patients starting systemic therapy for mRCC between 2002 and 2019. Patients with mixed histologic subtype were excluded. Statistical analysis was performed from February to June 2020.

EXPOSURES

Data regarding histologic subtype and sites of metastatic involvement at the time of first systemic therapy initiation were collected.

MAIN OUTCOMES AND MEASURES

The primary outcomes were prevalence of metastatic site involvement and overall survival (OS) from time of systemic therapy initiation. Patients with multiple sites of metastatic involvement were included in analyses of all groups to which they had metastases.

RESULTS

A total of 10 105 patients were eligible for analysis. Median (interquartile range) age at diagnosis was 60 (53-67) years, 7310 (72.4%) were men and 8526 (84.5%) underwent nephrectomy. Of these, 9252 (92%) had ccRCC, 667 (7%) had pRCC, and 186 (2%) had chrRCC. The median number of sites of metastasis was 2 (range, 0-7). In ccRCC, the most common sites of metastasis were lung (70%; 6189 of 8804 patients [448 missing]), lymph nodes (45%; 3874 of 8655 patients [597 missing]), bone (32%; 2847 of 8817 patients [435 missing]), liver (18%; 1560 of 8804 [448 missing]), and adrenal gland (10%; 678 of 6673 patients [2579 missing]). Sites of metastasis varied between subtypes. Lung, adrenal, brain, and pancreatic metastases were more frequent in ccRCC, lymph node involvement was more common in pRCC, and liver metastases were more frequent in chrRCC. Median OS for ccRCC varied by site of metastatic involvement, ranging between 16 months (95% CI, 13.7-18.8 months) for the pleura and 50 months (95% CI, 41.1-55.5 months) for the pancreas. Compared with ccRCC, patients with pRCC tended to have lower OS, regardless of metastatic site.

CONCLUSIONS AND RELEVANCE

Sites of metastatic involvement differ according to histologic subtype in mRCC and are associated with OS. These data highlight the clinical and biological variability between histologic subtypes of mRCC. Patterns of metastatic spread may reflect differences in underlying disease biology. Further work to investigate differences in immune, molecular, and genetic profiles between metastatic sites and histologic subtypes is encouraged.

Outcomes of patients with metastatic renal cell carcinoma with sarcomatoid dedifferentiation to immune checkpoint inhibitors

INTRODUCTION

Metastatic renal cell carcinoma with sarcomatoid dedifferentiation (sRCC) is associated with poor survival outcomes. We aimed to analyze the efficacy and safety of immune checkpoint inhibitors (ICI) in patients with sRCC comparing clear-cell (sccRCC) to non-clear cell epithelial histology (snccRCC).

METHODS

We performed retrospective analysis of sRCC patients who received ICI at MD Anderson Cancer Center (n = 48, 41 with ccRCC and 7 with nccRCC) to determine the overall survival (OS), progression-free survival (PFS), and objective response rate (ORR). Additionally, we performed a prespecified multivariable Cox regression comparing survival outcomes between sccRCC and snccRCC.

RESULTS

The ORR for the entire cohort was 35.4% (95% confidence interval [CI]: 23.4%, 49.6%), including 8 (16.7%) patients (95% CI: 8.7%, 29.6%) who achieved a complete remission. The disease control rate was 52% (95% CI: 38.3%, 65.5%). In patients with sccRCC, the ORR was 39% (95% CI: 25.7%, 54.3%) and disease control rate 58.5% (43.4%, 72.2%). Among 7 snccRCC patients, only one (14.3%) achieved an objective partial response. At a median follow-up of 51.1 months, the median PFS was 4.9 months (95% CI: 2.7, 16.3) and the median OS was 28.4 months (95% CI: 15.8, NA) for the entire cohort. For patients with sccRCC, the median PFS was 8.9 months, with median OS of 30.1 months, compared with median PFS of 2.3 months (HR 0.25 [95% CI: 0.08, 0.78]; P= 0.0145) and median OS of 6.7 months (HR 0.13 [95% CI 0.04, 0.44]; P=0.0009) for patients with snccRCC.

CONCLUSION

ICIs appear to be effective in sccRCC while the treatment of snccRCC remains challenging.

Chromophobe renal cell carcinoma: current and controversial issues

It has been 35 years since Professor Thoenes and his colleagues discovered chromophobe renal cell carcinoma (RCC). Since then, our knowledge about this tumour entity has changed and novel tumour entities have been discovered. The aim of this review is to discuss recent molecular findings and open questions in diagnosing chromophobe-like/oncocytic neoplasms. The broader differential diagnosis of chromophobe-like and oncocytoma-like neoplasms includes SDH-deficient renal cell carcinoma, fumarate hydratase (FH) deficient RCC, epitheloid angiomyolipoma ('oncocytoma like'), MiT family translocation RCC and the emerging entity of eosinophilic solid and cystic renal cell carcinoma. After separation of these tumours from chromophobe RCC, it becomes evident that chromophobe RCC are low malignant tumours with a 5-6% risk of metastasis. Recent next generation sequencing (NGS) and DNA methylation profiling studies have confirmed Thoenes' theory of a distal tubule derived origin of chromophobe RCC and renal oncocytomas. Comprehensive genomic analyses of chromophobe RCC have demonstrated a low somatic mutation rate and identified TP53 and PTEN as the most frequently mutated genes, whereas 'unclassified' RCC with oncocytic or chromophobe-like features can show somatic inactivating mutations of TSC2 or activating mutations of MTOR as the primary molecular alterations. For the future, it would be desirable to create a category of 'oncocytic/chromophobe RCC, NOS' with the potential of further molecular studies for identification of TSC1/2 mutations in these rare tumours.

Genetic Alterations in Renal Cancers: Identification of The Mechanisms Underlying Cancer Initiation and Progression and of Therapeutic Targets

Renal cell cancer (RCC) involves three most recurrent sporadic types: clear-cell RCC (70-75%, CCRCC), papillary RCCC (10-15%, PRCC), and chromophobe RCC (5%, CHRCC). Hereditary cases account for about 5% of all cases of RCC and are caused by germline pathogenic variants. Herein, we review how a better understanding of the molecular biology of RCCs has driven the inception of new diagnostic and therapeutic approaches. Genomic research has identified relevant genetic alterations associated with each RCC subtype. Molecular studies have clearly shown that CCRCC is universally initiated by Von Hippel Lindau (VHL) gene dysregulation, followed by different types of additional genetic events involving epigenetic regulatory genes, dictating disease progression, aggressiveness, and differential response to treatments. The understanding of the molecular mechanisms that underlie the development and progression of RCC has considerably expanded treatment options; genomic data might guide treatment options by enabling patients to be matched with therapeutics that specifically target the genetic alterations present in their tumors. These new targeted treatments have led to a moderate improvement of the survival of metastatic RCC patients. Ongoing studies based on the combination of immunotherapeutic agents (immune check inhibitors) with VEGF inhibitors are expected to further improve the survival of these patients.

An overview of the clinical use of cabozantinib in the treatment of advanced non-clear-cell renal cell carcinoma (NCCRCC)

Patients diagnosed with non-clear renal cell carcinoma have often been excluded from clinical trials due to the shortage of treatments available, the low incidence of tumours with non-clear histology, and the corresponding diversity of intrinsic molecular features. This approach led to a knowledge gap in finding the optimal treatment for patients diagnosed with non-clear cell renal carcinoma. Cabozantinib, a potent multiple tyrosine kinase receptor inhibitor, has been recently investigated in patients with non-clear cell histologies of renal cell cancer. In this review, we have summarized available data on the use of cabozantinib in non-clear renal cell carcinoma.

Outcomes Associated with First-Line anti-PD-1/ PD-L1 agents vs. Sunitinib in Patients with Sarcomatoid Renal Cell Carcinoma: A Systematic Review and Meta-Analysis

Immunotherapy based on anti PD-1/PD-L1 inhibitors has proven to be more effective than sunitinib in the first-line setting of advanced renal cell carcinoma (RCC). RCC patients with sarcomatoid histology (sRCC) have a poor prognosis and limited therapeutic options. We performed a systematic review and a meta-analysis of randomized-controlled trials (RCTs) of first-line anti PD-1/PDL-1 agents vs. sunitinib, presenting efficacy data in the sub-group of sRCC patients. The systematic research was conducted on Google Scholar, Cochrane Library, PubMed and Embase and updated until 31th January, 2020. Abstracts from ESMO and ASCO (2010–2019) were also reviewed. Full texts and abstracts reporting about RCTs testing first-line anti-PD-1/ PD-L1 agents vs. sunitinib in RCC were included if sRCC sub-group analyses of either PFS (progression-free survival), OS (overall survival) or radiological response rate were available. Pooled data from 3814 RCC patients in the ITT (intention-to-treat) population and from 512 sRCC patients were included in the quantitative synthesis. In the sRCC sub-group vs. the ITT population, pooled estimates of the PFS-HRs were 0.57 (95%: 0.45–0.74) vs. 0.79 (95% CI: 0.70–0.89), respectively, with a statistically meaningful interaction favoring the sRCC sub-group (pooled ratio of the PFS-HRs = 0.64; 95% CI: 0.50–0.82; p < 0.001). Pooled estimates of the difference in CR-R (complete response-rate) achieved with anti-PD-1/PDL-1 agents vs. sunitinib were + 0.10 (95% CI: 0.04–0.16) vs. + 0.04 (95% CI: 0.00–0.07) in the sRCC vs. the non-sRCC sub groups, with a statistically meaningful difference of + 0.06 (95% CI: 0.02–0.10; p = 0.007) favoring the sRCC sub-group. Sarcomatoid histology may be associated with improved efficacy of anti PD-1/PDL-1 agents vs. sunitinib in terms of PFS and CR-R.

Multi-institutional re-evaluation of prognostic factors in chromophobe renal cell carcinoma: proposal of a novel two-tiered grading scheme

A histological grading system of chromophobe renal cell carcinoma (chRCC) is highly desirable to identify approximately 5-10% of tumors at risk for progression. Validation studies failed to demonstrate a correlation between the four-tiered WHO/ISUP grade and outcome. Previous proposals with three-tiered chromophobe grading systems could not be validated. In this study, the presence of sarcomatoid differentiation, necrosis, and mitosis was analyzed in a Swiss cohort (n = 42), an Italian cohort (n = 103), a German cohort (n = 54), a Japanese cohort (n = 119), and The Cancer Genome Atlas cohort (n = 64). All 3 histological parameters were significantly associated with shorter time to tumor progression and overall survival in univariate analysis. Interobserver variability for identification of these parameters was measured by Krippendorff's alpha coefficient and showed high concordance for the identification of sarcomatoid differentiation and tumor necrosis, but only low to medium concordance for the identification of mitosis. Therefore, we tested a two-tiered tumor grading system (low versus high grade) based only on the presence of sarcomatoid differentiation and/or necrosis finding in the combined cohorts (n = 382). pT stage, patient's age (> 65 vs ≤ 65), lymph node and/or distant metastasis, and the two-tiered grading system (low versus high grade) were significantly associated with overall survival and were independent prognostic parameters in multivariate analysis (Cox proportional hazard). This multi-institutional evaluation of prognostic parameters suggests tumor necrosis and sarcomatoid differentiation as reproducible components of a two-tiered chromophobe tumor grading system.

Chromophobe Renal Cell Carcinoma: Results From a Large Single-Institution Series

BACKGROUND

The purpose of the study was to evaluate clinical features and prognostic factors in a large single institutional cohort of chromophobe renal cell carcinoma (ChRCC) patients for identification of tumors with the highest metastatic potential.

PATIENTS AND METHODS

Clinicopathological parameters of all patients with ChRCC diagnosed and surgically treated at Memorial Sloan Kettering Cancer Center between 1990 and 2016 were identified and compared with patients treated for clear-cell renal cell carcinoma (ccRCC) in the same study period using Wilcoxon test for continuous variables and Fisher exact test for categorical variables. Recurrence-free survival (RFS) and overall survival (OS) were analyzed using the Kaplan-Meier method, log rank test, and Cox proportional hazards regression.

RESULTS

Four hundred ninety-six patients with ChRCC (10-year RFS, 91.7% and OS, 82.1%) and 3312 patients with ccRCC (10-year RFS, 79.4% and OS, 63.6%) were included in the analysis. Patients with ChRCC were younger (median 59 vs. 61 years; P = .0015), less frequently male (54.8% vs. 66.3%; P < .0001), showed more favorable T stages (T1-2 in 78% vs. 67%; P < .0001) and less frequent sarcomatoid differentiation (1.2 % vs. 4%; P = .0008) and showed lower rates of metastatic development compared with ccRCC patients. Larger tumor size, sarcomatoid differentiation, and higher T-stage are significantly associated with adverse RFS and OS in chromophobe tumors.

CONCLUSION

ChRCC is more commonly diagnosed in female and younger patients and is associated with a more favorable clinical outcome and a lower propensity for metastatic development than ccRCC. Larger tumors and sarcomatoid differentiation of ChRCC might be considered as risk factors for metastatic development.