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

[2022 WHO classification of renal cell carcinomas: Focus on papillary renal cell carcinoma]

Renal cell carcinomas (RCC) represent a group of heterogeneous tumors whose classification has greatly evolved since 1981. The latest update in 2022 classifies all renal cell carcinomas into six categories according to their morphology or the detection of specific molecular alterations. Molecular disassembly of renal cell carcinomas with papillary features has enabled the identification of new entities characterized by a specific molecular alteration, such as Fumarate Hydratase (FH) deficient RCC, TFE3-rearranged RCC or TFEB-altered RCC. This new classification allows for a more accurate diagnosis but requires a thorough knowledge of the genomic alterations to search for with immunohistochemical or molecular biology techniques. According to the new WHO 2022 classification, papillary renal cell carcinoma (PRC) type 1 or type 2 classification is no longer recommended. A classification based on nucleolar ISUP grade must be preferred: low-grade PRC (ISUP 1-2) or high-grade PRC (ISUP 3-4). The other prognostic factors remain the same: the pTNM stage, lymphovascular invasion, and the presence or absence of dedifferentiated areas referring to sarcomatoid or rhabdoid features. Of note, the presence of necrosis is not currently recognized as a poor prognostic element for this type of carcinoma. The diagnosis of high-grade PRC is from now on a diagnosis of exclusion. It can only be sustained after having ruled out TFE3-rearranged RCC, TFEB-altered RCC, and FH-deficient RCC. For clinicians, the diagnosis of PRC implies suggesting an oncogenetic consultation to screen for an associated genetic tumor syndrome regardless of the patient's age.

Development and validation of prognostic nomograms for adult with papillary renal cell carcinoma: A retrospective study

OBJECTIVE

The aim of the study was to create two consensus nomograms for predicting Overall Survival (OS) and Cancer-Specific Survival (CSS) in adults with papillary Renal Cell Carcinoma (pRCC).

METHODS

Using the Surveillance, Epidemiology, and End Results databases, a retrospective analysis of 1,074 adults with pRCC from 2004 to 2015 was performed. These patients were then randomly divided into two independent cohorts with a ratio of 7:3 (training cohort: 752; validation cohort: 322). In a retrospective analysis of 752 patients from the training cohort, independent prognostic variables affecting OS and CSS were found. R software was used to create prognostic nomograms based on the findings of Cox regression analysis. The performance of the nomograms was assessed using the Concordance Index (C-index), the Area Under Curve (AUC), a calibration curve, and Decision Curve Analysis (DCA). Data from the 107 postoperative pRCC patients at the Affiliated Hospital of Xuzhou Medical University were used for external validation of the nomogram.

RESULTS

For OS and CSS, the C-indices and AUCs of the training cohort and the validation cohort indicated that the model had excellent discrimination. The DCA demonstrated that the model was clinically applicable, and the calibration curves in the internal and external validations showed that the model's accuracy was high.

CONCLUSION

The authors developed and validated a prognostic nomogram that accurately predicted the 3-, 5-, and 8-year OS and CSS of adults with pRCC. Clinicians can use this knowledge to direct the clinical management and counseling of patients with pRCC.

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.

Metabolic alterations in hereditary and sporadic renal cell carcinoma

Kidney cancer is the seventh leading cause of cancer in the world, and its incidence is on the rise. Renal cell carcinoma (RCC) is the most common form and is a heterogeneous disease comprising three major subtypes that vary in their histology, clinical course and driver mutations. These subtypes include clear cell RCC, papillary RCC and chromophobe RCC. Molecular analyses of hereditary and sporadic forms of RCC have revealed that this complex and deadly disease is characterized by metabolic pathway alterations in cancer cells that lead to deregulated oxygen and nutrient sensing, as well as impaired tricarboxylic acid cycle activity. These metabolic changes facilitate tumour growth and survival. Specifically, studies of the metabolic features of RCC have led to the discovery of oncometabolites - fumarate and succinate - that can promote tumorigenesis, moonlighting functions of enzymes, and substrate auxotrophy owing to the disruption of pathways that enable the production of arginine and cholesterol. These metabolic alterations within RCC can be exploited to identify new therapeutic targets and interventions, in combination with novel approaches that minimize the systemic toxicity of metabolic inhibitors and reduce the risk of drug resistance owing to metabolic plasticity.

Papillary Renal Cell Carcinoma: Demographics, Survival Analysis, Racial Disparities, and Genomic Landscape

Papillary renal cell carcinoma (PRCC) is the second most common histological subtype of renal cell cancer. This research aims to present a large database study highlighting the demographic, clinical, and pathological factors, racial disparities, prognosis, and survival of PRCC. The clinical and demographic data were extracted from the Surveillance, Epidemiology, and End Results (SEER) database, and molecular data was cured from the Catalogue Of Somatic Mutations in Cancer (COSMIC) database. PRCC had a median age of diagnosis at 64 years, with a higher incidence in men (77%), and Whites (68%). 70.3% of cases were Grades I-IV (13, 53, 31, and 3%, respectively). In patients with known data, 85% were localized to the kidney, and 84% of cases were 7 cm in size. No metastasis occurred in 97% of the known data. The most common treatment offered was surgical resection (9%). The 5-year overall survival was 79%, with patients undergoing surgery having a 90.6% 5-year survival. Multivariable analysis revealed age > 60 years, Black race, poor histologic differentiation, distant metastases, and tumor size > 10 cm as independent risk factors for mortality. The most common mutations identified from the COSMIC database were MET, KMT2D, KMT2C, ARID1A, and SPEN. PRCC affects male individuals in the sixth decade of life. Increased age, Black race, distant metastases, and tumors > 10 cm are associated with a worse prognosis. Surgical resection offers a favorable survival outcome. Next-generation sequencing (NGS) could identify potentially targetable alterations and future personalized therapeutic approaches.

ABCC2 brush-border expression predicts outcome in papillary renal cell carcinoma: a multi-institutional study of 254 cases

AIMS

Papillary renal cell carcinoma (PRCC) histologic subtyping is no longer recommended in the 2022 WHO classification. Currently, WHO/ISUP nucleolar grade is the only accepted prognostic histologic parameter for PRCC. ABCC2, a renal drug transporter, has been shown to significantly predict outcomes in PRCC. In this study we evaluated the prognostic significance of ABCC2 IHC staining patterns in a large, multi-institutional PRCC cohort and assessed the association of these patterns with ABCC2 mRNA expression.

METHODS AND RESULTS

We assessed 254 PRCCs for ABCC2 IHC reactivity patterns that were stratified into negative, cytoplasmic, brush-border <50%, and brush-border ≥50%. RNA in situ hybridization (ISH) was used to determine the transcript level of each group. Survival analysis was performed with SPSS and GraphPad software. RNA-ISH showed that the ABCC2 group with any brush-border staining was associated with a significant increase in the transcript level, when compared to the negative/cytoplasmic group (P = 0.034). Both ABCC2 groups with brush-border <50% (P = 0.024) and brush-border ≥50% (P < 0.001) were also associated with worse disease-free survival (DFS) in univariate analysis. Multivariate analysis showed that only ABCC2 IHC brush-border (<50% and ≥50%) reactivity groups (P = 0.037 and P = 0.003, respectively), and high-stage disease (P < 0.001) had a DFS of prognostic significance. In addition, ABCC2 brush-border showed significantly worse DFS in pT1a (P = 0.014), pT1 (P = 0.013), ≤4 cm tumour (P = 0.041) and high stage (P = 0.014) groups, while a similar analysis with high WHO/ISUP grade in these groups was not significant.

CONCLUSION

ABCC2 IHC brush-border expression in PRCC correlates with significantly higher gene expression and also independently predicts survival outcomes.

Unusual Cutaneous Lesions in a 53-Year-Old Female: A Potential Indicator of Underlying Renal Cell Carcinoma

Hereditary leiomyomatosis and renal cell cancer (HLRCC) is a rare autosomal dominant genetic disorder resulting from mutations in the fumarate hydratase (FH) gene. It is characterised by a predisposition to cutaneous and uterine leiomyomas (fibroids) and an aggressive form of renal cell carcinoma (RCC). We report the case of a 53-year-old female who presented with an unusual rash in the context of a personal and family history of uterine leiomyomas requiring hysterectomy. A skin biopsy confirmed cutaneous leiomyomas and subsequent genetic testing demonstrated a pathogenic heterozygous mutation on exon 7 of the FH gene, confirming a diagnosis of HLRCC. Due to the recognised association with renal cell carcinoma in this syndrome, abdominal imaging was performed, which excluded RCC, and the patient was commenced on lifelong surveillance with annual abdominal magnetic resonance imaging.

The Role of the Pathologist in Renal Cell Carcinoma Management

Recent advances in our understanding of the molecular alterations underlying different types of renal cell carcinoma (RCC), as well as the implementation of immune checkpoint inhibitors in the treatment of patients with advanced disease, have significantly expanded the role of pathologists in the management of RCC patients and in the identification of predictive biomarkers that can guide patient treatment. In this chapter, we examine pathologists' evolving role in patient care and the development of precision medicine strategies for RCC.

[First-line treatment of metastatic renal cell carcinoma]

In recent years the first-line treatment of metastatic renal cell carcinoma was revolutionized by the introduction of checkpoint inhibitors (CPI). Within a few years several combined modality treatments with CPI and tyrosine kinase inhibitors (TKI) have proven to be effective and safe in the application. According to the guidelines, up to five different combined modality treatments can now be considered, depending on the risk profile. Based on the current data situation, a direct distinction between the treatments cannot be made as no comparative studies are available. Therefore, the decision for a particular treatment is often guided by individual factors. In particular, a clear processing of the patient with the respective risk factors and tumor identity is essential. Hence, it is all the more important to discuss complex cases in an interdisciplinary tumor board.

Evaluation of Gas 6 as a Prognostic Marker in Papillary Renal Cell Carcinoma

INTRODUCTION

Growth arrest-specific protein 6 (Gas 6) is a ligand that plays a role in proliferation and migration of cells. For several tumor entities, high levels of Gas 6 are associated with poorer survival. We examined the prognostic role of Gas 6 in renal cell carcinoma (RCC), especially in papillary RCC (pRCC), which is still unclear.

METHODS

The patients' sample collection is a joint collaboration of the PANZAR consortium. Patients' medical history and tumor specimens were collected from n = 240 and n = 128 patients with type 1 and 2 pRCC, respectively. Expression of Gas 6 was determined by immunohistochemistry.

RESULTS

In total, Gas 6 staining was evaluable in 180 of 240 type 1 and 110 of 128 type 2 pRCC cases. Kaplan-Meier analysis disclosed no significant difference in 5-year overall survival for all pRCC nor either subtype. Also, Gas+ and Gas- groups did not significantly differ in any tumor or patient characteristics.

CONCLUSION

Gas 6 was not found to be an independent prognostic marker in pRCC. Future studies are warranted to determine if Gas 6 plays a role as prognostic marker or therapeutic target in pRCC.

WHO 2022 landscape of papillary and chromophobe renal cell carcinoma

The 5th edition of the WHO Classification of Tumours of the Urinary and Male Genital Systems contains relevant revisions and introduces a group of molecularly defined renal tumour subtypes. Herein we present the World Health Organization (WHO) 2022 perspectives on papillary and chromophobe renal cell carcinoma with emphasis on their evolving classification, differential diagnosis, and emerging entities. The WHO 2022 classification eliminated the type 1/2 papillary renal cell carcinoma (pRCC) subcategorization, given the recognition of frequent mixed tumour phenotypes and the existence of entities with a different molecular background within the type 2 pRCC category. Additionally, emerging entities such as biphasic squamoid alveolar RCC, biphasic hyalinising psammomatous RCC, papillary renal neoplasm with reverse polarity, and Warthin-like pRCC are included as part of the pRCC spectrum, while additional morphological and molecular data are being gathered. In addition to oncocytomas and chromophobe renal cell carcinoma (chRCC), a category of 'other oncocytic tumours' with oncocytoma/chRCC-like features has been introduced, including emerging entities, most with TSC/mTOR pathway alterations (eosinophilic vacuolated tumour and so-called 'low-grade' oncocytic tumour), deserving additional research. Eosinophilic solid and cystic RCC was accepted as a new and independent tumour entity. Finally, a highly reproducible and clinically relevant universal grading system for chRCC is still missing and is another niche of ongoing investigation. This review discusses these developments and highlights emerging morphological and molecular data relevant for the classification of renal cell carcinoma.

[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.

Unique Growth Pattern Presentation of a Papillary Renal Cell Carcinoma

Papillary renal cell carcinoma (PRCC) is defined by the WHO 2022 classification as a malignant tumor derived from the renal tubular epithelium. However, the WHO 2016 classification subdivided PRCC into two types, with type 1 PRCC showing papillae covered by a single layer of neoplastic cells, and type II PRCC, which can show multiple types of histologies and is more aggressive. The WHO 2022 classification eliminated the subcategorization of PRCC. Here, we present a histopathological case study with a 4-year follow-up diagnosed in 2018 as type I PRCC (WHO 2016) with intra-pyelocalyceal growth pattern in a 59-year-old male patient with a history of Type II diabetes mellitus, left-sided renal–ureteral lithiasis, and benign hypertrophy of the prostate. Microscopically the tumor was composed of small cuboidal cells with inconspicuous nucleoli, arranged on a single layer of tubulo-papillary cores, and scant, foamy macrophages. The tumor had a non-infiltrative, expansive pyelocalyceal growth pattern. Immunohistochemically (IHC), the tumor cells were CK7-intense and diffusely positive, and stained granular for AMACR. Next-generation sequencing (NGS) was performed for the tumor and the normal adjacent tissue for in-depth pathological characterization. To our knowledge, this is the first reported case where a PRCC displays this unique intra-pyelocalyceal growth pattern, mimicking a urothelial cell carcinoma of the renal pelvis system.

Papillary renal cell carcinoma: current and controversial issues

PURPOSE OF THE REVIEW

Papillary renal cell carcinoma (pRCC) is the second most frequent renal cancer subtype and represents 15-20% of all RCC. Classification of pRCC is changing because novel tumour entities have been discovered in the last years. In this review, we summarise recent studies relevant for the understanding of the molecular complexity and the broader differential diagnosis of pRCC.

RECENT FINDINGS

It has been 25 years ago, that pRCC was morphologically subdivided into type 1 and type 2. Recently described tumour entities in the 2022 WHO classification challenged this concept and allow a new view on the molecular background in pRCC. Biphasic hyalinizing psammomatous RCC and papillary renal neoplasm with reversed polarity are emerging tumour entities derived from the new concept of molecularly defined RCC subtypes. Immune checkpoint inhibition and tyrosine kinase inhibitors have been introduced as the new backbone in the first-line treatment of advanced pRCCs. To identify novel targeted treatments for patients with pRCC it is crucial to investigate the specific molecular background of pRCC considering emerging pRCC subtypes.

SUMMARY

In the future, a deeper understanding of the correlation between molecular aberrations and new pRCC subtypes may improve the classification of pRCC patients and could reveal potential predictive biomarkers for each subgroup.

Differential Diagnosis of Type 1 and Type 2 Papillary Renal Cell Carcinoma Based on Enhanced CT Radiomics Nomogram

Objectives

To construct a contrast-enhanced CT-based radiomics nomogram that combines clinical factors and a radiomics signature to distinguish papillary renal cell carcinoma (pRCC) type 1 from pRCC type 2 tumours.

Methods

A total of 131 patients with 60 in pRCC type 1 and 71 in pRCC type 2 were enrolled and divided into training set (n=91) and testing set (n=40). Patient demographics and enhanced CT imaging characteristics were evaluated to set up a clinical factors model. A radiomics signature was constructed and radiomics score (Rad-score) was calculated by extracting radiomics features from contrast-enhanced CT images in corticomedullary phase (CMP) and nephrographic phase (NP). A radiomics nomogram was then built by incorporating the Rad-score and significant clinical factors according to multivariate logistic regression analysis. The diagnostic performance of the clinical factors model, radiomics signature and radiomics nomogram was evaluated on both the training and testing sets.

Results

Three validated features were extracted from the CT images and used to construct the radiomics signature. Boundary blurring as an independent risk factor for tumours was used to build clinical factors model. The AUC value of the radiomics nomogram, which was based on the selected clinical factors and Rad-score, were 0.855 and 0.831 in the training and testing sets, respectively. The decision curves of the radiomics nomogram and radiomics signature in the training set indicated an overall net benefit over the clinical factors model.

Conclusion

Radiomics nomogram combining clinical factors and radiomics signature is a non-invasive prediction method with a good prediction for pRCC type 1 tumours and type 2 tumours preoperatively and has some significance in guiding clinicians selecting subsequent treatment plans.

Giant Polycystic Papillary Renal Cell Carcinoma: A Case Report and Literature Review

Introduction

Giant, cystic renal tumors are generally considered relatively contraindicated for laparoscopic surgery. We report on a 19-year-old male, where polycystic lesions in the left kidney were accidentally noted by enhanced computed tomography (CT) by focusing on the diagnostic, clinical, and surgery to the patient.

Case Report

Enhanced CT scan revealed solid component in multiple cystic lesions of Bosniak IV, which was enhanced after injection of contrast agent and the left kidney lost normal profile and enlarged with maximal diameter more than 18cm. Positron emission tomography-computed tomography (PET-CT) showed SUVmax 4.8 of the lesion and suggested malignant disease. A retroperitoneal laparoscopic radical left nephrectomy was performed successfully without cyst burst and the lesion was 17×17×18 cm in size. Pathological examination revealed that the lesions were consistent with papillary renal cell carcinoma (type 2, WHO grade II), no renal capsule invasion, no renal pelvis and renal sinus fat involvement, no abnormality in ureter and renal arteriovenous end, no abnormality in a few adrenal tissues, chronic inflammation of hilar lymph nodes (0/1). After surgery, no specific treatment was initiated and at a follow-up visit 1 year after surgery, no local recurrence or metastasis was found.

Conclusion

It is the largest cystic renal cell carcinoma that has ever been reported for laparoscopic resection. The selection of surgery for giant cystic renal cell carcinoma should be individualized. Retroperitoneal laparoscopy may be an option for such lesions.

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.

Expression of the CXCR4 and CXCR7 in renal cancers; can "the orphan receptor" predict the mortality?

CXCR4 and CXCR7 are chemokine receptors that bind with chemokine CXCL12 and influence various physiological and pathological processes. In renal cell carcinoma, their expression has been mostly associated with tumour aggressiveness. However, there are some contradictory results regarding the localization of immunohistochemical staining and predictive potential of these markers. The expression of CXCR4 and CXCR7 was immunohistochemicaly analyzed in 98 tumour samples, including 85 clear cell type (ccRCC) and 13 papillary type (pRCC). Depending on the staining localization (cytoplasmatic or membranous), intensity and percentage of stained cells, histoscores were calculated, and their association with clinicopathological parameters was analyzed. PRCC was associated with both CXCR7 and CXCR4 cytoplasmatic expression. We have also found that higher CXCR7 expression can be expected in tumours of greater size. In our study, mortality could be predicted by membranous CXCR7 histoscore, tumour size and pRCC type. With each centimetre in tumour size, survival decreases 1.2 times. CXCR7M histoscore higher by 50 units was associated with 1.5 greater risk of mortality. Neither membranous nor cytoplasmatic CXCR4 histoscore was found to be mortality predictor. Our data showed that CXCR7 could be considered as a valid prognostic marker regarding survival of RCC patients.

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.