The subclassification of papillary renal cell carcinoma does not affect oncological outcomes after nephron sparing surgery

An epidemiological and clinicopathological study of type 1 vs. type 2 morphological subtypes of papillary renal cell carcinoma- results from a nation-wide study covering 50 years in Iceland

INTRODUCTION

Papillary renal cell carcinoma (pRCC) is the second most common histology of renal cell carcinoma (RCC), accounting for 10-15% of cases. Traditionally, pRCC is divided into type 1 and type 2, although this division is currently debated as a prognostic factor of survival. Our aim was to investigate the epidemiology and survival of the pRCC subtypes in a whole nation cohort of patients during a 50-year period.

MATERIALS AND METHODS

A Population based retrospective study including consecutive cases of RCC in Iceland from 1971-2020. Comparisons were made between histological classifications of RCC, with emphasis on pRCC subtypes (type 1 vs. 2) for outcome estimation. Changes in RCC incidence were analyzed in 5-year intervals after age standardization. The Kaplan-Meier method and Cox regression were used for outcome analysis.

RESULTS

A total of 1.725 cases were identified, with 74.4%, 2.1% and 9.2% having clear cell (ccRCC), chromophobe (chRCC), and pRCC, respectively. The age standardized incidence (ASI) of pRCC was 1.97/100.000 for males and 0.5/100.000 for females, and the proportion of pRCC increased from 3.7% to 11.5% between the first and last intervals of the study (p < 0.001). Age standardized cancer specific mortality (ASCSM) of pRCC was 0.6/100.000 and 0.19/100.000 for males and females, respectively. The annual average increase in ASI was 3.6% for type 1 pRCC, but the ASI for type 2 pRCC and ASCSM for both subtypes did not change significantly. Male to female ratio was 4.4 for type 1 pRCC and 2.3 for type 2. The average tumor size for type 1 and 2 was 58.8 and 73.7 mm, respectively. Metastasis at diagnosis was found in 8.7% in the type 1 pRCC, compared to 30.0% of patients with type 2 pRCC (p < 0.001). Estimated 5-year cancer-specific survival (CSS) were 94.4%, 80.7%, and 69.3% for chRCC, pRCC and ccRCC, respectively (p < 0.001). For the pRCC subtypes, type 1 was associated with better 5-year CSS than type 2 (86.3% vs. 66.0%, p < 0.001), although this difference was not significant after adjusting for cancer stage and grading.

CONCLUSIONS

pRCC histology was slightly less common in Iceland than in other countries. Males are more than three times more likely to be diagnosed with pRCC, compared to other RCC histologies. The subtype of pRCC was not found to be an independent risk factor for worse survival, and as suggested by the most recent WHO Classification of Urinary Tumors, grade and TNM-stage seem to be the most important factors for estimation of survival for pRCC patients.

The prognostic role of histomorphological subtyping in nonmetastatic papillary renal cell carcinoma after curative surgery: is subtype really irrelevant? A propensity score matching analysis of a multi-institutional real life data

BACKGROUND AND AIM

The role of histomorphological subtyping is an issue of debate in papillary renal cell carcinoma (papRCC). This multi-institutional study investigated the prognostic role of histomorphological subtyping in patients undergoing curative surgery for nonmetastatic papRCC.

PATIENTS AND METHODS

A total of 1,086 patients undergoing curative surgery were included from a retrospectively collected multi-institutional nonmetastatic papRCC database. The patients were divided into 2 groups based on histomorphological subtyping (type 1, n = 669 and type 2, n = 417). Furthermore, a propensity score-matching (PSM) cohort in 1:1 ratio (n = 317 for each subtype) was created to reduce the effect of potential confounding variables. The primary outcome of the study, the predictive role of histomorphological subtyping on the prognosis (recurrence free survival [RFS], cancer specific survival [CSS] and overall survival [OS]) in nonmetastatic papRCC after curative surgery, was investigated in both overall and PSM cohorts.

RESULTS

In overall cohort, type 2 group were older (66 vs. 63 years, P = 0.015) and more frequently underwent radical nephrectomy (37.4% vs. 25.6%, P < 0.001) and lymphadenectomy (22.3% vs. 15.1%, P = 0.003). Tumor size (4.5 vs. 3.8 cm, P < 0.001) was greater, and nuclear grade (P < 0.001), pT stage (P < 0.001), pN stage (P < 0.001), VENUSS score (P < 0.001) and VENUSS high risk (P < 0.001) were significantly higher in type 2 group. 5-year RFS (89.6% vs. 74.2%, P < 0.001), CSS (93.9% vs. 84.2%, P < 0.001) and OS (88.5% vs. 78.5%, P < 0.001) were significantly lower in type 2 group. On multivariable analyses, type 2 was a significant predictor for RFS (HR:1.86 [95%CI:1.33-2.61], P < 0.001) and CSS (HR:1.91 [95%CI:1.20-3.04], P = 0.006), but not for OS (HR:1.27 [95%CI:0.92-1.76], P = 0.150). In PSM cohort balanced with age, gender, symptoms at diagnosis, pT and pN stages, tumor grade, surgical margin status, sarcomatoid features, rhabdoid features, and presence of necrosis, type 2 increased recurrence risk (HR:1.75 [95%CI: 1.16-2.65]; P = 0.008), but not cancer specific mortality (HR: 1.57 [95%CI: 0.91-2.68]; P = 0.102) and overall mortality (HR: 1.01 [95%CI: 0.68-1.48]; P = 0.981) CONCLUSIONS: This multiinstitutional study suggested that type 2 was associated with adverse histopathologic outcomes, and predictor of RFS and CSS after surgical treatment of nonmetastatic papRCC, in overall cohort. In propensity score-matching cohort, type 2 remained the predictor of RFS. Eventhough 5th WHO classification for renal tumors eliminated histomorphological subtyping, these findings suggest that subtyping is relevant from the point of prognostic view.

Radical versus partial nephrectomy for T1 non-clear cell renal cell carcinoma

INTRODUCTION

Nephron-sparing surgery is the recommended surgical management of T1 renal cell carcinoma (RCC). However, non-clear cell RCC (nccRCC) is heterogeneous and included many histological types. Therefore, the present study was performed to compare radical nephrectomy (RN) versus partial nephrectomy (PN) in nccRCC.

MATERIALS AND METHODS

Within the Surveillance, Epidemiology, and End Results registry (2000-2019), the patients with nccRCC were identified. Kaplan-Meier survival curve and the log-rank test were conducted. Univariate analysis and multivariate Cox regression analysis were performed to explore the prognostic factors.

RESULTS

A total of 7575 patients with nccRCC were included, of which papillary RCC (n = 5219) is the major histology. Kaplan-Meier plots and log-rank tests showed that nccRCC patients who underwent RN had significantly worse overall survival (OS) and cancer-specific survival (CSS) than those who received PN (all P < 0.05). Multivariate analysis also revealed that RN was significantly associated with poor OS and CSS in nccRCC patients. Stratified by histological types, the multivariate analysis also revealed that RN was significantly associated with poor OS in papillary and chromophobe (all P < 0.05). Besides, the multivariable analysis indicated that RN was associated with poor CSS in papillary RCC (P < 0.05). For other histology, the patients who received RN had a comparable survival to those who received PN.

CONCLUSION

For patients with T1 nccRCC, our findings revealed that PN was not inferior to RN in OS and CSS. PN may be also the preferred option for T1 nccRCC, but more prospective studies are required to validate this finding.

Comparison and validation of different risk models for papillary renal cell carcinoma

BACKGROUND

Several prognostic algorithms were specifically or nonspecifically used for papillary renal cell carcinoma (PRCC). No consensus was reached upon their efficacy of discrimination. We aim to compare the stratifying ability of current models or systems in predicting the risk of recurrence of PRCC.

METHODS

A PRCC cohort consisting of 308 patients from our institution and 279 patients from The Cancer Genome Atlas (TCGA) was generated. With ISUP grade, TNM classification, UCLA Integrated Staging System (UISS), STAGE, SIZE, GRADE AND NECROSIS (SSIGN), Leibovich model and VENUSS system, recurrence-free survival (RFS), disease-specific survival (DSS) and overall survival (OS) were studied using Kaplan-Meier method and concordance index (c-index) was compared. Differences between risk groups in gene mutation and infiltration of inhibitory immune cells were studied with TCGA database.

RESULTS

All the algorithms were able to stratify patients in RFS as well as DSS and OS (all P < 0.001). VENUSS score and risk group generally had the highest and balanced c-index (0.815 and 0.797 for RFS). ISUP grade, TNM stage and Leibovich model had the lowest c-indexes in all analysis. Among the 25 most frequently mutated genes in PRCC, eight had different mutation frequency between VENUSS low- and intermediate-/high-risk patients and mutated KMT2D and PBRM1 resulted in worsened RFS (P = 0.053 and P = 0.007). Increased Treg cells in tumors of intermediate-/high- risk patients were also identified.

CONCLUSIONS

VENUSS system showed better predictive accuracy in RFS, DSS and OS compared with SSIGN, UISS and Leibovich risk models. VENUSS intermediate-/high-risk patients had increased frequency of mutation in KMT2D and PBRM1 and increased infiltration of Treg cells.

Identification and verification of prognostic cancer subtype based on multi-omics analysis for kidney renal papillary cell carcinoma

Background

Identifying Kidney Renal Papillary Cell Carcinoma (KIRP) patients with high-risk, guiding individualized diagnosis and treatment of patients, and identifying effective prognostic targets are urgent problems to be solved in current research on KIRP.

Methods

In this study, data of multi omics for patients with KIRP were collected from TCGA database, including mRNAs, lncRNAs, miRNAs, data of methylation, and data of gene mutations. Data of multi-omics related to prognosis of patients with KIRP were selected for each omics level. Further, multi omics data related to prognosis were integrated into cluster analysis based on ten clustering algorithms using MOVICS package. The multi omics-based cancer subtype (MOCS) were compared on biological characteristics, immune microenvironmental cell abundance, immune checkpoint, genomic mutation, drug sensitivity using R packages, including GSVA, clusterProfiler, TIMER, CIBERSORT, CIBERSORT-ABS, quanTIseq, MCPcounter, xCell, EPIC, GISTIC, and pRRophetic algorithms.

Results

The top ten OS-related factors for KIRP patients were annotated. Patients with KIRP were divided into MOCS1, MOCS2, and MOCS3. Patients in the MOCS3 subtype were observed with shorter overall survival time than patients in the MOCS1 and MOCS2 subtypes. MOCS1 was negatively correlated with immune-related pathways, and we found global dysfunction of cancer-related pathways among the three MOCS subtypes. We evaluated the activity profiles of regulons among the three MOCSs. Most of the metabolism-related pathways were activated in MOCS2. Several immune microenvironmental cells were highly infiltrated in specific MOCS subtype. MOCS3 showed a significantly lower tumor mutation burden. The CNV occurrence frequency was higher in MOCS1. As for treatment, we found that these MOCSs were sensitive to different drugs and treatments. We also analyzed single-cell data for KIRP.

Conclusion

Based on a variety of algorithms, this study determined the risk classifier based on multi-omics data, which could guide the risk stratification and medication selection of patients with KIRP.

[Clinicopathological features and prognostic analysis of papillary renal cell carcinoma]

OBJECTIVE

To investigate the clinicopathological features and prognostic characteristics of papillary renal cell carcinoma (pRCC).

METHODS

The clinical data of 114 patients with pRCC, including 91 males and 23 females, admitted to the Department of Urology, Peking University Third Hospital from May 2012 to May 2021 were retrospectively analyzed. All the cases were operated patients with clear pathological diagnosis and complete follow-up data. The log-rank test was used to analyze the relationship between the patients' clinicopathological characteristics and survival time, the Kaplan-Meier method to draw survival curves, and the Cox regression model for univariate and multifactorial analysis.

RESULTS

The mean age of the 114 patients was (57.3±12.6) years. The tumors were located in the left kidney in 49 cases and in the right kidney in 65 cases. In the study, 48 radical nephrectomies and 66 partial nephrectomies were performed, 42 cases were type 1 and 72 cases were type 2, and the mean maximum tumor diameter was (5.5±3.6) cm. pT1a stage 52 cases, pT1b stage 22 cases, pT2 stage 4 cases, pT3 stage 33 cases, and pT4 stage 3 cases were staged. According to the World Health Organization / International Society of Urological Pathology (WHO/ISUP), there were 13 cases of gradeⅠ, 44 cases of grade Ⅱ, 51 cases of grade Ⅲ, and 6 cases of grade Ⅳ. And 34 of the 114 patients had vascular cancer embolism, 30 cases had lymph node metastasis, and 3 cases had adrenal metastasis. The median follow-up time after surgery was 22 months, and the 3-year progression-free survival rate was 95.6%. The patients with type 1 and type 2 pRCC showed statistically significant differences in age (P=0.046), body mass index (P=0.008), surgical approach (P=0.001), maximum tumor diameter (P < 0.001), vascular cancer embolism (P < 0.001), lymph node metastasis (P < 0.001), pT stage (P < 0.001), and nuclear grade (P < 0.001). The 3-year progression-free survival rates for type 1 and type 2 pRCC were 100% and 69.4%, respectively, with type 1 having a significantly better prognosis than with type 2 (P=0.003). Univariate analysis of the patients with type 2 pRCC showed that pT stage (P < 0.001), vascular cancer embolism (P < 0.001) and lymph node metastasis (P < 0.001) were strongly associated with their prognosis. Multifactorial analysis showed that vascular cancer embolism was an independent prognostic factor for progression-free survival in type 2 pRCC (P=0.001). Univariate analysis of the pRCC patients undergoing radical nephrectomy showed that pT stage (P=0.006), vascular cancer embolism (P=0.001), and lymph node metastasis (P=0.008) were significant factors affecting their prognosis, and further multifactorial analysis showed that only vascular cancer embolism was an indepen-dent prognostic factor for their progression-free survival (P=0.006).

CONCLUSION

Type 2 pRCC has more morbidity, more lymph node metastases, more advanced pT stage, and higher pathologic grading than type 1 pRCC. The presence of vascular cancer embolism is an independent prognostic factor in patients with type 2 pRCC and pRCC undergoing radical nephrectomy.

Impact of Renal Cell Carcinoma Histological Variants on Recurrence After Partial Nephrectomy: A Multi-Institutional, Prospective Study (UROCCR Study 82)

BACKGROUND

The prognostic impact of renal cell carcinoma (RCC) morphotype remains unclear in patients who undergo partial nephrectomy (PN). Our objective was to determine the risk factors for recurrence after PN, including RCC morphotype.

METHODS

Patients with RCC who had undergone PN were extracted from the prospective, national French database, UroCCR. Patients with genetic predisposition, bilateral or multiple tumours, and those who had undergone secondary totalization were excluded. Primary endpoint was 5-year, recurrence-free survival (RFS), and secondary endpoint was overall survival (OS). Risk factors for recurrence were assessed by multivariable Cox regression analysis.

RESULTS

Overall, 2,767 patients were included (70% male; median age: 61 years [interquartile range (IQR) 51-69]). Most (71.5%) of the PN procedures were robot-assisted. Overall, 2,573 (93.0%) patients were recurrence free, and 74 died (2.7%). Five-year RFS was 84.9% (IQR 82.4-87.4). A significant difference in RFS was observed between RCC morphotypes (p < 0.001). Surgical margins (hazard ratio [HR] = 2.0 [95% confidence interval (CI): 1.3-3.2], p < 0.01), pT stage >1 (HR = 2.6 [95% CI: 1.8-3.7], p < 0.01]) and Fuhrmann grade >2 (HR = 1.9 [95% CI: 1.4-2.6], p < 0.001) were risk factors for recurrence, whereas chromophobe subtype was a protective factor (HR = 0.08 [95% CI: 0.01-0.6], p = 0.02). Five-year OS was 94.0% [92.4-95.7], and there were no significant differences between RCC subgroups (p = 0.06). The main study limitation was its design (multicentre national database), which may be responsible for declarative bias.

CONCLUSIONS

Chromophobe morphotype was significantly associated with better RFS in RCC patients who underwent PN. Conversely, pT stage, Fuhrman group and positive surgical margins were risk factors for recurrence.

Bioinformatics Study Identified EGF as a Crucial Gene in Papillary Renal Cell Cancer

Background

Due to a lack of knowledge of the disease process, papillary renal cell carcinoma (PRCC) has a dismal outlook. This research was aimed at uncovering the possible biomarkers and the underlying principles in PRCC using a bioinformatics method.

Methods

We searched the Gene Expression Omnibus (GEO) datasets to obtain the GSE11151 and GSE15641 gene expression profiles of PRCC. We used the R package limma to identify the differentially expressed genes (DEGs). The online tool DAVID and ClusterProfiler package in R software were used to analyze Gene Ontology and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway dominance, respectively. The STRING database was utilized to construct the PPI network of DEGs. Using the Cytoscape technology, a protein-protein interaction (PPI) network that associated with DEGs was created, and the hub genes were identified using the Cytoscape plug-in CytoHubba. The hub genes were subjected to a Kaplan-Meier analysis to identify their correlations with survival rates.

Results

From the selected datasets, a total of 240 common DEGs were identified in the PRCC, including 50 upregulated genes and 190 downregulated regulated genes. Renal growth, external exosome, binding of heparin, and metabolic processes were all substantially associated with DEGs. The CytoHubba plug-in-based analysis identified the 10 hub genes (ALB, KNG1, C3, CXCL12, EGF, TIMP1, VCAN, PLG, LAMC1, and CASR) from the original PPI network. The higher expression group of EGF was associated with poor outcome in patients with PRCC.

Conclusions

We revealed important genes and proposed biological pathways that may be implicated in the formation of PRCC. EGF might be a predictive biomarker for PRCC and therefore should be investigated as a novel treatment strategy.

Stemness-associated senescence genes as potential novel risk factors for papillary renal cell carcinoma

Background

Papillary renal cell carcinoma (PRCC) is the 2nd most common type of renal carcinoma; however, there is limited data about PRCC, and strategies for the diagnosis and treatment of PRCC need to be identified.

Methods

In this study, the stemness-associated senescence (SAS) phenotype of PRCC was obtained by a bioinformatics analysis. We acquired the gene expression profiles of patients with PRCC and calculated the PRCC messenger ribonucleic acid stemness index (mRNAsi). We then screened the SAS genes from the GenAge database. A least absolute shrinkage and selection operator-Cox regression was conducted to examine correlations between risk signatures and the abundance of the SAS genes in the PRCC samples. Functional enrichment analyses were then performed via molecular co-expression studies of mRNAsi, and the risk scores of PRCC patients were calculated.

Results

We identified the following 8 SAS signatures that were strongly associated with prognosis in PRCC patients: cyclin-dependent kinase 1, heat shock protein family D member 1, platelet-derived growth factor receptor A, cyclin-dependent kinase inhibitor 2B, pyrroline-5-carboxylate reductase 1, sequestosome-1, sirtuin-3, and cyclin-dependent kinase inhibitor 1A. The SAS signatures were significantly associated with the stage and type of PRCC. The calculated risk scores can be used to divide PRCC patients into low- and high-risk groups, and provide guidance in determining treatment plans.

Conclusions

We have developed a reliable prognostic tool to predict the clinical outcomes of PRCC patients. This tool could improve treatment decisions regarding drug therapy, surgery, and conservative options.

Clinicopathological Features and Prognostic Outcomes of Papillary Renal Cell Carcinoma

Purpose

Although papillary renal cell carcinoma (pRCC) is the second common renal malignant tumor, the current understanding of pRCC is poor. This study aims to explore the clinicopathological features and prognostic factors of pRCC.

Methods

From August 2007 and August 2017, 87 patients diagnosed with pRCC by postoperative pathology were enrolled. The clinicopathological features between type1 pRCC and type2 pRCC were compared by Chi-square test, Fisher’s exact test, or t-test. The Kaplan–Meier method was performed to estimate progression-free survival (PFS). Univariate and multivariate cox regression models were used to verify the prognostic factors.

Results

Of the 87 cases, the median tumor diameter was 5.3cm. Twenty-nine patients were diagnosed with type1 pRCC and 58 patients with type2 pRCC. According pathological stage, 59 (67.8%) cases were in pT1 stage, 19 (21.8%) in pT2 stage, and 9 (10.4%) in pT3 stage. WHO/ISUP pathological grade revealed that 56 (64.4%) patients were in grade I, 17 (19.5%) in grade II, 7 (8.05%) in grade III, and 7 (8.05%) in grade IV. The median follow-up time was 57.0months, and the 1-, 3-year PFS was 95.4%, and 80.8%, respectively. For type1 and type2 pRCC, 3-years PFS was 93.0% and 74.9%, respectively. Survival of type1 pRCC was better than that of type2 (P= 0.027). Patients with late pT stage, lymph node metastasis, distant metastasis, high pathological grade, and large size exhibited worse survival. pTNM stage, pathological grade, and tumor types were potentially related to prognosis for PFS. However, an independent prognostic factor affecting PFS was not found in multivariate regression models. For patients with the pT1 stage, nephron-sparing surgery (NSS) and radical nephrectomy (RN) did not affect the PFS, ignoring tumor types (P=0.45).

Conclusion

Type2 pRCC is more than type1 pRCC and has an advanced TNM stage and a higher pathological grade. For patients with pRCC with the pT1 stage, the outcome of NSS is not inferior to that of RN.

The Clinicopathological Features and Prognosis in Patients With Papillary Renal Cell Carcinoma: A Multicenter Retrospective Study in Chinese Population

Objective

The purpose of this study was to compare the clinicopathological characteristics of type 1 and type 2 papillary renal cell carcinoma (PRCC) and to explore the prognostic factors of PRCC in the Chinese population.

Methods

A total of 242 patients with PRCC from five Chinese medical centers were retrospectively included. From them, 82 were type 1 PRCC and 160 were type 2 PRCC. Clinicopathological features and oncologic outcomes were reviewed. The Kaplan-Meier analysis and log-rank test were performed to describe the progression-free survival (PFS) and overall survival (OS). Univariate and multivariate Cox proportional hazards regression models were used to analyze the prognostic factors of PRCC.

Results

Of the 242 patients, the average age at surgery was 55.3 ± 13.1 years. The mean tumor size was 5.1 ± 3.1 cm. Compared with type 1 PRCC patients, type 2 PRCC patients had a larger tumor size and were more likely to undergo radical nephrectomy. Besides, type 2 PRCC patients had higher tumor stage (p < 0.001) and WHO International Society of Urological Pathology (WHO/ISUP) grading (p < 0.001). Furthermore, tumor necrosis was more common in type 2 PRCC than type 1 PRCC (p = 0.030). The Kaplan-Meier survival analysis showed that the PFS and OS of type 1 PRCC patients were significantly better than those of type 2 PRCC patients (p = 0.0032 and p = 0.0385, respectively). Univariate analysis showed that tumor size, surgical procedures, pT stage, WHO/ISUP grading, and microvascular invasion were significant predictors of PFS and OS for type 2 PRCC patients. In the multivariate analysis, only pT stage (p = 0.004) and WHO/ISUP grading (p = 0.010) were the independent risk factors. Among type 2 PRCC patients with pT1 stage, no significant difference was found in PFS and OS between the partial nephrectomy and radical nephrectomy groups (p = 0.159 and p = 0.239, respectively).

Conclusion

This multi-institutional study reveals the significant differences in clinicopathological variables and oncologic outcomes between type 1 and 2 PRCC. For type 2 PRCC in pT1 stage, the prognosis of partial nephrectomy is not inferior to that of radical nephrectomy, and nephron-sparing surgery can be considered.

Whether histologic subtyping affect the oncological outcomes of patients with papillary renal cell carcinoma: evidence from a systematic review and meta-analysis

Background

Whether the histologic subtype (type 1 and type 2) of papillary renal cell carcinoma (pRCC) is a tool to predict the prognosis is of great debate. This study is aimed to evaluate the prognostic significance of histologic subtype in patients with pRCC after surgery through a systematic review and meta-analysis.

Methods

We searched PubMed, the Web of Science, Cochrane library and EMBASE databases to identify studies published until January 20, 2021 according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Studies were deemed eligible if they compared the overall survival (OS), cancer specific survival (CSS), recurrence-free survival (RFS) or disease-free survival (DFS) between patients with type 1 or type 2 pRCC. And the corresponding hazard ratios (HRs) and 95% conference intervals (CIs) were collected for meta-analysis and further subgroup analysis.

Results

Overall 22 studies with a total of 4,494 patients were considered eligible and included for the systematic review and meta-analysis. The pooled results showed that type 2 pRCC was associated with a worse OS (pooled HR 1.61, 95% CI: 1.10–2.36, P=0.02) and CSS (pooled HR 1.59, 95% CI: 1.00–2.51, P=0.05). However, the subgroup analysis yielded the same result as the initial analysis only when the HRs were extracted from univariate analysis. In studies with multivariate analysis, type 2 pRCC was not statistically associated with a worse OS (pooled HR 1.22, 95% CI: 0.97–1.53, P=0.27), CSS (pooled HR 1.16, 95% CI: 0.67–2.00, P=0.60), and DFS (pooled HR 1.33, 95% CI: 0.93–1.91, P=0.12) compared to type 1 pRCC.

Discussion

Histologic subtype is not an independent prognostic factor for patients with pRCC, although the result needs to be taken with caution. And studies with retrospective study design, larger sample size and longer follow-up period are required to verify these results.

The first competing risk survival nomogram in patients with papillary renal cell carcinoma

There is still a lack of competing risk analysis of patients with papillary renal cell carcinoma (pRCC) following surgery. We performed the cumulative incidence function (CIF) to estimate the absolute risks of cancer-specific mortality (CSM) and other-cause mortality (OCM) of pRCC over time, and constructed a nomogram predicting the probability of 2-, 3- and 5-year CSM based on competing risk regression. A total of 5993 pRCC patients who underwent nephrectomy between 2010 and 2016 were identified from the Surveillance, Epidemiology, and End Results (SEER) database. The 2-, 3-, 5-year CSM rates were 3.2%, 4.4% and 6.5%, respectively, and that of OCM were 3.2%, 5.0% and 9.3%, respectively. The estimates of 5-year cumulative mortality were most pronounced among patients aged > 75 years in OCM (17.0%). On multivariable analyses, age, tumor grade, T stage, N stage, and with or without bone, liver and lung metastases were identified as independent predictors of CSM following surgery and were integrated to generate the nomogram. The nomogram achieved a satisfactory discrimination with the AUC_t of 0.730 at 5-year, and the calibration curves presented impressive agreements. Taken together, age-related OCM is a significant portion of all-cause mortality in elderly patients and our nomogram can be used for decision-making and patient counselling.

Papillary renal cell carcinoma: Review

Kidney cancer is the 13th most common malignancy globally, and the incidence is rising. Papillary renal cell carcinoma is the second most common subtype, comprising 10-15% of renal cell carcinomas. Though the histologic features of this subtype were initially described in the 1990's, our understanding of the genetic and molecular characteristics of this disease have rapidly evolved over the past decade. In this review, we summarize the contemporary understanding of the clinical, morphologic, radiographic, and genetic characteristics of papillary renal cell carcinoma, as well as clinical considerations, current options for management, and prognosis.

The effect of the papillary renal cell carcinoma subtype on oncological outcomes

The study aimed to compare the clinicopathological features and prognosis between type I and type II papillary renal cell carcinoma (PRCC) and to investigate whether the subtypes of PRCC would affect oncological outcomes. A total of 102 patients with PRCC were recruited, of which 42 were type I PRCC and 60 type II. The clinicopathological features and oncologic outcomes of the patients were evaluated. The type II cases had a higher WHO/ISUP grading (P < 0.001), T (P = 0.003), N (P = 0.010) stage and stage grouping (P = 0.011) than the type I. During a median follow-up period of 61.4 months, 1-year cancer specific survival (CSS) of the type I was 100%, 5-year CSS was 95.2%, the 1-year CSS of the type II was 96.2%, and 5-year CSS was 75.7%. The univariate analysis showed that subtype, symptoms, TNM, stage grouping, WHO/ISUP grading and surgical methods appeared to affect prognosis of the patients with PRCC. However, multivariate analysis revealed that only stage grouping was the independent risk factor. After the stage grouping factor was adjusted for the analysis, there were no statistically significant differences in CSS (P = 0.214) and PFS (P = 0.190) between the localized type I and type II PRCC groups. Compared with type I PRCC, type II had higher pathological T, N stage and WHO/ISUP grading. However, it was the Stage grouping that made a great difference to oncological outcomes, rather than the subtype of PRCC.

Development and Validation of an Individualized Immune-Related Gene Pairs Prognostic Signature in Papillary Renal Cell Carcinoma

Papillary renal carcinoma (PRCC) is one of the important subtypes of kidney cancer, with a high degree of heterogeneity. At present, there is still a lack of robust and accurate biomarkers for the diagnosis, prognosis and treatment selection of PRCC. Considering the important role of tumor immunity in PRCC, we aim to construct a signature based on immune-related gene pairs (IRGPs) to estimate the prognostic of patients with PRCC. We obtained gene expression profiling and clinical information of patients with PRCC from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO), which were divided into discovery (n = 287) and validation (n = 28) cohorts, respectively. By univariate analysis, multivariate Cox analysis, and least absolute shrinkage and selection operator (Lasso) analysis, we selected 14 IRGPs with a panel of 22 unique genes to construct the prognostic signature. According to the signature, we stratified patients into high-risk group and low-risk group. In both discovery and validation cohorts, the results of Kaplan-Meier analysis showed that there were significant differences in OS between the two groups (p < 0.001). Combined with multiple clinical and pathological factors, the results of multivariate analyses confirmed that this signature was an independent predictor of OS (HR, 3.548; 95%CI, 2.096-6.006; p < 0.001). The results of immune infiltration analysis demonstrated that the abundance of multiple tumor-infiltration lymphocytes such as CD8 + T cells, Tregs, and T follicular cell helper were significantly higher in the high-risk group. Functional analysis showed that multiple immune-related signaling pathways were enriched in the high-risk group. In conclusion, we successfully established an individualized prognostic IRGPs signature, which can accurately assess and predict the OS of patients with PRCC.

Mitophagy-associated genes PINK1 and PARK2 are independent prognostic markers of survival in papillary renal cell carcinoma and associated with aggressive tumor behavior

The aim of this study was to investigate the mitophagy-related genes PINK1 and PARK2 in papillary renal cell carcinoma and their association with prognosis. In silico data of PINK1 and PARK2 were analyzed in TCGA cohorts of papillary renal cell carcinoma comprising 290 tumors and 33 corresponding non-neoplastic renal tissues. Protein expression data from a cohort of 95 papillary renal cell carcinoma patients were analyzed and associated with clinical-pathological parameters including survival. PINK1 and PARK2 were significantly downregulated in papillary renal cell carcinoma at transcript and protein levels. Reduced transcript levels of PINK1 and PARK2 were negatively associated with overall survival (p < 0.05). At the protein level, PARK2 and PINK1 expression were positively correlated (correlation coefficient 0.286, p = 0.04) and reduced PINK1 protein expression was prognostic for shorter survival. Lower PINK1 protein levels were found in tumors with metastases at presentation and in tumors of higher pT-stages. The multivariate analysis revealed mRNA expression of PINK1 and PARK2 as well as PINK1 protein expression as independent prognostic factors for shorter overall survival. The downregulation of PINK1 is a strong predictor of poor survival in papillary renal cell carcinoma. Immunohistochemical PINK1 expression in resected pRCC should be considered as an additional prognostic marker for routine practice.

Comparison of clinicopathologic parameters and oncologic outcomes between type 1 and type 2 papillary renal cell carcinoma

BACKGROUND

To compare the clinicopathologic parameters and oncologic outcomes between type 1 and type 2 papillary renal cell carcinoma (PRCC).

METHODS

This study was approved by the review board (NO.XYFY2019-KL032-01). Between 2007 and 2018, 52 consecutive patients who underwent surgery at a single tertiary referral hospital were included. Clinicopathologic and survival data were collected and entered into a database. The Kaplan-Meier method, and univariate and multivariate Cox proportional hazard regression analyses were performed to estimate progression-free survival (PFS) and cancer-specific survival (CSS).

RESULTS

Of the 52 patients, 24 (46.2%) were diagnosed with type 1 PRCC, and 28 (53.8%) had type 2 PRCC. The mean tumor size was 4.8 ± 2.5 cm. The two subtypes displayed different morphological features: foamy macrophages were more common in type 1 PRCC, while eosinophils and microvascular angiolymphatic invasion were more frequent in type 2 PRCC. Type 2 cases showed higher tumor stage and World Health Organization/International Society of Urological Pathology (WHO/ISUP) grade than type 1 cases (T3-T4: 43% vs 17%, P = 0.041; G3-G4: 43% vs 8%, P = 0.005). In univariate analysis, type 2 PRCC had a lower probability for PFS and CSS than patients with type 1 PRCC (P = 0.016, P = 0.049, log-rank test, respectively). In multivariate analysis, only WHO/ISUP grade (HR 11.289, 95% CI 2.303-55.329, P = 0.003) and tumor size (HR 1.244, 95% CI 1.034-1.496, P = 0.021) were significantly associated with PFS.

CONCLUSIONS

PRCC subtype displayed different morphological features: foamy macrophages, eosinophils and microvascular angiolymphatic invasion are pathologic features that may aid in the distinction of the two subtypes. Histologic subtype of PRCC is not an independent prognostic factor and only WHO/ISUP grade and tumor size were independent predictors for PFS.

Renal Cell Tumors: Molecular Findings Reshaping Clinico-pathological Practice

Over the past 20 years, the number of subtypes of renal epithelial cell neoplasia has grown. This growth has resulted from detailed histological and immunohistochemical characterization of these tumors and their correlation with clinical outcomes. Distinctive molecular phenotypes have validated the unique nature of many of these tumors. This growth of unique renal neoplasms has continued after the 2016 World Health Organization (WHO) Classification of Tumours. A consequence is that both the pathologists who diagnose the tumors and the clinicians who care for these patients are confronted with a bewildering array of renal cell carcinoma variants. Many of these variants have important clinical features, i.e. familial or syndromic associations, genomics alterations that can be targeted with systemic therapy, and benignancy of tumors previously classified as carcinomas. Our goal in the review is to provide a practical guide to help recognize these variants, based on small and distinct sets of histological features and limited numbers of immunohistochemical stains, supplemented, as necessary, with molecular features.

Prognostic factors for the survival of patients with papillary renal cell carcinoma after surgical management

PURPOSE

To examine the possible prognostic factors in patients with type 1 and type 2 papillary renal cell carcinoma (pRCC) after surgical management and to identify the independent predictive factors of the prognosis.

METHODS

From 2010 to 2017, 1405 patients underwent surgery for renal cell carcinoma, of whom 114 had type 1 or type 2 pRCC and follow-up data were available for 88 patients. Clinicopathological and prognostic parameters were compared between type 1 and type 2 pRCC. Possible prognostic factors were retrospectively analyzed by univariate and multivariate analyses with Cox regression.

RESULTS

The study included 63 males and 25 females with a mean age of 54.27 ± 12.91. 53 patients were diagnosed by regular physical examination and others presented with hematuria or lumbago. 53 (60.2%) underwent radical nephrectomy and 35 (39.8%) underwent nephron sparing surgery. After a mean follow-up of 46.08 ± 22.65 months, 16 patients died of pRCC metastasis and the 5-year disease-specific survival was 79.3%. The comparison of the 39 (44.3%) type 1 and 49 (55.7%) type 2 pRCCs revealed that type 2 pRCC had significantly higher grade and worse prognosis. Univariate analysis showed that symptomatic diagnosis, type, grade, and tumor stage were prognostic factors. Multivariate analysis identified that type and tumor stage were independent factors of the prognosis.

CONCLUSIONS

Pathological type and tumor stage could serve as independent factors for the prognosis of patients with pRCC.

Morphologic subtyping as a prognostic predictor for survival in papillary renal cell carcinoma: Type 1 vs. type 2

OBJECTIVE

To evaluate outcomes of surgically treated patients with clinically localized papillary renal cell carcinoma (RCC) and determine if papillary RCC subtype is associated with recurrence and survival.

METHODS

This is a historical cohort study using the prospectively maintained Canadian Kidney Cancer Information System database between January 2011 and September 2018. All patients underwent partial or radical nephrectomy. Patient, tumor, treatment, and outcomes were compared between papillary RCC type 2 and type 1 cohorts.

RESULTS

During the study period, 509 patients had clinically localized papillary RCC type 2 (n = 172) or type 1 (n = 337) histology. Sex, race, and comorbidities were similar between groups. Pathologic stage (pT3 or pT4), nuclear grade (3 or 4), and tumor diameter were higher in the type 2 papillary RCC cohort (P < 0.0001). A greater proportion of type 2 papillary RCC patients received radical nephrectomy (42.4% vs. 24.6%, P< 0.0001). More type 2 papillary RCC patients underwent lymph node dissection (19.6% vs. 5.5%, P< 0.0001) and had lymph node metastases removed during surgery (6.4% vs. 0.6%, P= 0.103). Overall, adjusting for age, grade, pathologic stage, positive nodes, and tumor size, type 2 papillary RCC had worse outcomes compared to type 1, as demonstrated by elevated all-cause mortality (hazard ratio = 7.7 [95% confidence interval: 2.0-28.9]), P=0.0027) and worse recurrence-free survival (hazard ratio = 8.2 [95% confidence interval: 3.6-19.0], P< 0.0001).

CONCLUSION

Patients with clinically localized type 2 papillary RCC present with higher risk disease and have worse prognosis compared to patients with clinically localized type 1 papillary RCC. To the best of our knowledge, this is the largest cohort study comparing papillary RCC subtypes.

Prognostic factors and prognostic models for renal cell carcinoma: a literature review

PURPOSE

Following curative treatment for localised renal cell carcinoma (RCC), up to 30% of patients develop tumour recurrence. Prognostic scores are essential to guide individualised surveillance protocols, patient counselling and potentially in the future to guide adjuvant therapy. In metastatic RCC, prognostic scores are routinely used for treatment selection in clinical practice as well as in all major trials.

METHODS

We performed a literature review on the current evidence based on prognostic factors and models for localised and metastatic RCC.

RESULTS

A number of prognostic factors have been identified, of which tumour node metastasis classification remains the most important. Multiple prognostic models and nomograms have been developed for localised disease, based on a combination of tumour stage, grade, subtype, clinical features, and performance status. However, there is poor level of evidence for their routine use. Prognostic scores for patients with metastatic RCC receiving targeted treatments are used routinely, but have limited accuracy. Molecular markers can improve the accuracy of established prognostic models, but frequently lack external, independent validation.

CONCLUSION

Several factors and models predict prognosis of localised and metastatic RCC. They represent valuable tools to provide estimates of clinically important endpoints, but their accuracy should be improved further. Validation of molecular markers is a future research priority.

Outcome of papillary versus clear cell renal cell carcinoma varies significantly in non-metastatic disease

Renal cell carcinoma (RCC) comprises a heterogenous group of tumors. Traditionally, papillary RCC (pRCC) is associated with a favorable outcome compared to clear cell RCC (ccRCC), while other series report equivalent or worse prognosis. In this paper we comparatively evaluate outcome of pRCC versus ccRCC in two large multi-institutional databases (cohort study), including distribution of pRCC subtypes 1 and 2. Retrospective data of 1,943 surgically treated pRCC patients from 17 European/ North American centers between 1984–2015 were compared to 5,600 ccRCC patients from a database comprising 11 European/ North American centers (1984–2011). Median follow-up was 64.6 months. Differences between pRCC, subtypes, and ccRCC were compared with t-tests, Chi^2-tests, and exact Fisher tests. Cancer-specific mortality was analyzed with cumulative incidence curves and Cox cause-specific hazard models. The robustness of our results was examined with sensitivity analyses. We present that cancer-specific mortality rates and variables as stage, lymph node, and distant metastasis differ significantly between groups. Furthermore, we demonstrate that patients with non-metastatic pRCC had a significantly better cancer-specific mortality (HR 0.76, p = 0.007), when compared to ccRCC. Additionally, pRCC type 2 versus ccRCC exhibited no difference in cancer-specific mortality (HR 0.9, p = 0.722), whereas pRCC type 1 versus ccRCC displayed a risk of death reduced by 69% (p = 0.044). Taken together, outcome of pRCC versus ccRCC varies significantly in non-metastatic disease. Furthermore, pRCC type 2 exhibited no difference in cancer-specific mortality, whereas pRCC type 1 displayed a significantly reduced risk of death. Consequently, there is urgent need to respect histopathological entities and their subtypes, when assigning follow-up or targeted therapy to RCC patients.

Histologic subtype needs to be considered after partial nephrectomy in patients with pathologic T1a renal cell carcinoma: papillary vs. clear cell renal cell carcinoma

PURPOSE

We compared the oncological outcomes of papillary renal cell carcinoma (pRCC) with clear cell renal cell carcinoma (ccRCC) after partial nephrectomy (PN) in patients with pathologic T1a RCC.

METHODS

After excluding patients with synchronous multiple renal tumors, familial RCC, and pathologic stage T1b or above, 759 patients with ccRCC and 84 patients with pRCC were included. We assessed the impact of histologic subtypes on oncologic outcomes after PN in patients with pathologic T1a RCC (median follow-up duration, 67 months).

RESULTS

There was no difference in patient and tumor characteristics between the 2 groups, except Fuhrman grade (p = 0.006). Kaplan-Meier analysis identified 5-year recurrence-free survival of 98.7 and 95.6% in patients with ccRCC and pRCC, respectively. However, 10-year recurrence-free survival in patients with ccRCC and pRCC was 96.1 and 73.0%, respectively (p < 0.001). Recurrence ≥5 years post surgery was more common in patients with pRCC compared with those with ccRCC (0.3 vs. 4.8%; p < 0.001). In multivariate analysis, pRCC [hazard ratio (HR) 5.309; p = 0.001] was a significant risk factor for recurrence after PN in patients with pathologic T1a RCC, in addition to larger tumor size (HR 1.861; p = 0.038) and Fuhrman grade ≥3 (HR 5.176; p = 0.003).

CONCLUSIONS

In patients with pathologic T1a RCC, recurrence after PN occurred more commonly in pRCC compared with ccRCC. As over half of the recurrence cases in patients with pRCC occurred ≥5 years post surgery, a longer follow-up time is required, even for those with pathologic stage T1a disease.

The radiologist's role in the management of papillary renal cell carcinoma

Papillary carcinoma is the second most common renal cell carcinoma. It has a better prognosis than the more frequent clear cell carcinoma, although this does not hold true for advanced cases, because no specific treatment exists. It presents as a circumscribed peripheral tumor (small and homogeneously solid or larger and cystic/hemorrhagic) or as an infiltrating lesion that invades the veins, which has a worse prognosis. Due to their low vascular density, papillary renal cell carcinomas enhance less than other renal tumors, and this facilitates their characterization. On computed tomography, they might not enhance conclusively, and in these cases they are impossible to distinguish from hyperattenuating cysts. Contrast-enhanced ultrasonography and magnetic resonance imaging are more sensitive for detecting vascularization. Other characteristics include a specific vascular pattern, hypointensity on T2-weighted images, restricted water diffusion, and increased signal intensity in opposed phase images. We discuss the genetic, histologic, clinical, and radiological aspects of these tumors in which radiologists play a fundamental role in management.

Warthin-like papillary renal cell carcinoma: Clinicopathologic, morphologic, immunohistochemical and molecular genetic analysis of 11 cases

Oncocytic papillary renal cell carcinoma (PRCC) is a distinct subtype of PRCC, listed as a possible new variant of PRCC in the 2016 WHO classification. It is composed of papillae aligned by large single-layered eosinophilic cells showing linearly arranged oncocytoma-like nuclei. We analyzed clinicopathologic, morphologic, immunohistochemical and molecular-genetic characteristics of 11 oncocytic PRCCs with prominent tumor lymphocytic infiltrate, morphologically resembling Warthin's tumor. The patients were predominantly males (8/11, 73%), with an average age of 59years (range 14-76), and a mean tumor size of 7cm (range 1-22cm). Tumors had the features of oncocytic PRCCs with focal pseudostratification in 8/11 cases and showed dense stromal inflammatory infiltration in all cases. Papillary growth pattern was predominant, comprising more than 60% of tumor volume. Tubular and solid components were present in 5 and 3 cases, respectively. Uniform immunohistochemical positivity was found for AMACR, PAX-8, MIA, vimentin, and OSCAR. Tumors were mostly negative for carboanhydrase 9, CD117, CK20, and TTF-1. Immunohistochemical stains for DNA mismatch repair proteins MLH1 and PMS2 were retained in all cases, while MSH2 and MSH6 were negative in 1 case. Tumor infiltrating lymphocytes (TILs) consisted of both B and T cells. Chromosomal copy number variation analysis showed great variability in 5 cases, ranging from a loss of one single chromosome to complex genome rearrangements. Only one case showed gains of chromosomes 7 and 17, among other aberrations. In 4 cases no numerical imbalance was found. Follow up data was available for 9 patients (median 47.6months, range 1-132). In 6 patients no lethal progression was noted, while 3 died of disease. In conclusion, Warthin-like PRCC is morphologically very close to oncocytic PRCC, from which it differs by the presence of dense lymphoid stroma. Chromosomal numerical aberration pattern of these tumors is variable; only one case showed gains of chromosomes 7 and 17. Warthin-like PRCC is a potentially aggressive tumor since a lethal outcome was recorded in 3/9 cases.