Five-year analysis of a multi-institutional prospective clinical trial of delayed intervention and surveillance for small renal masses: the DISSRM registry

A Comparison of Cryoablation with Heat-Based Thermal Ablation for Treatment of Clinical T1a Renal Cell Carcinoma: A National Cancer Database Study

PURPOSE

To compare the overall survival (OS) of patients receiving cryoablation versus heat-based thermal ablation for clinical T1a renal cell carcinoma (RCC) in a large national cohort.

MATERIALS AND METHODS

Patients with RCC from 2004 to 2014 who were treated with ablation were identified from the National Cancer Database. OS was estimated with the use of the Kaplan-Meier method and evaluated by means of log-rank test, univariate and multivariate Cox proportional hazard regression, and propensity score-matched analysis.

RESULTS

A total of 3,936 patients who received cryoablation and 2,322 who received heat-based thermal ablation met the inclusion criteria. The mean age was 67 ± 12 year, and the mean size of tumors was 25 ± 8 mm. The 3-, 5-, and 10-year survival rates were, respectively, 91%, 82%, and 62% for cryoablation and 89%, 81%, and 55% for heat-based thermal ablation. After propensity score matching, cryoablation was associated with longer OS compared with heat-based thermal ablation (median 11.3 vs 10.4 years; hazard ratio 1.175, 95% CI 1.03-1.341; P = .016). For patients with tumors ≤2 cm, propensity score-matched analyses demonstrated no significant difference between the 2 treatment groups (P = .772).

CONCLUSIONS

Overall, cryoablation may be associated with longer OS compared with heat-based thermal ablation in cT1a RCC. No significant difference in survival rates was observed between the 2 treatments for patients with tumor sizes ≤2 cm. Owing to the inherent limitations of this study, further study with details on technology, local outcome, and complications is needed.

Management of small renal masses: An interventional radiologist's perspective

Renal cell carcinoma is relatively common malignancy. Its imaging features are often non-specific and can present a diagnostic dilemma for clinicians. Historically, all patients with a renal mass underwent radical nephrectomy. Advances in technology have allowed for an increase in partial nephrectomies and percutaneous ablations. This essay briefly describes some of the imaging findings of renal cell carcinoma and several of its mimics followed by an in-depth review of procedural management with a particular focus on recent advancements.

Circular RNA ABCB10 promotes tumor progression and correlates with pejorative prognosis in clear cell renal cell carcinoma

OBJECTIVE

Our study aimed to evaluate the effect of circular RNA ABCB10 (circ-ABCB10) on proliferation and apoptosis of clear cell renal cell carcinoma (ccRCC) cells, and its prognostic value in patients with ccRCC.

METHODS

Circ-ABCB10 expression in five ccRCC cell lines and normal kidney epithelial cell line was measured by quantitative polymerase chain reaction (qPCR). Empty overexpression, circ-ABCB10 overexpression, empty shRNA, and circ-ABCB10 shRNA plasmids were transfected into A498 cells as negative control for circ-ABCB10 over expression {NC (+)}, Circ-ABCB10(+), negative control (-){NC(-)}, and Circ-ABCB10(-) groups, then cell proliferation and apoptosis were evaluated by Cell Counting Kit-8 and annexin V/propidium iodide. Meanwhile, apoptotic markers were measured by western blot. Subsequently, circ-ABCB10 expression in tumor tissues and paired adjacent tissues from 120 ccRCC patients was measured by qPCR.

RESULTS

Circ-ABCB10 expression was elevated in all the ccRCC cell lines compared with the normal kidney cells line. A498 cell proliferation was enhanced in the Circ-ABCB10(+) group compared with the NC(+) group, while it was inhibited in the Circ-ABCB10(-) group compared with the NC (-) group; and A498 cell apoptosis was repressed in the Circ-ABCB10(+) group than the NC(+) group, but was promoted in the Circ-ABCB10(-) group compared with the NC(-) group. In addition, circ-ABCB10 was up-regulated in tumor tissues compared with paired adjacent tissues, and its high expression correlated with the advanced pathological grade and the tumor node metastasis stage as well as independently predicting worse overall survival in ccRCC patients.

CONCLUSION

Circ-ABCB10 promotes tumor progression and correlates with pejorative prognosis in ccRCC.

Harnessing the Genomic Landscape of the Small Renal Mass to Guide Clinical Management

CONTEXT

Small renal masses (SRMs; tumors <4 cm) encompass a diagnostic and therapeutic challenge. Genomic profiling has the potential to improve risk stratification and personalize treatment selection.

OBJECTIVE

Herein, we review the evidence regarding the utility, challenges, and potential implications of genomic profiling in the management of SRMs.

EVIDENCE ACQUISITION

Pertinent publications available on PubMed database pertaining to kidney cancer, tumor size, genomics, and clinical management were reviewed.

EVIDENCE SYNTHESIS

Compared with larger tumors, SRMs range from benign to lethal, necessitating strategies for improved treatment selection. Recent advances in the molecular characterization of renal cell carcinoma have improved our understanding of the disease; however, utility of these tools for the management of SRMs is less clear. While intratumoral heterogeneity (ITH) reduces the accuracy and reliability of sequencing, relative genomic uniformity of SRMs somewhat lessens the impact of ITH. Therefore, renal mass biopsy of SRMs represents an appealing opportunity to evaluate how incorporation of molecular profiles may improve management strategies.

CONCLUSIONS

Ongoing research into the genomic landscape of SRMs has advanced our understanding of the spectrum of disease aggressiveness and may hold promise in matching disease biology to treatment intensity.

PATIENT SUMMARY

Small renal masses are a clinical challenge, as they range from benign to lethal. Genomic profiling may eventually improve treatment selection, but more research is needed.

The Harms of Overdiagnosis and Overtreatment in Patients with Small Renal Masses: A Mini-review

Overdiagnosis and overtreatment refer to the detection and treatment of conditions that would not ultimately affect an individual's health. With increasing detection of small renal masses there is growing awareness of the overdiagnosis and overtreatment of these tumors, supported by studies showing that 15-30% of nephrectomy specimens are pathologically benign, and that many small renal cell carcinomas are indolent. The harms of overdiagnosis and overtreatment are numerous, including psychosocial stressors and renal morbidity, in addition to unnecessary surgical complications. A greater understanding of the potential harms of overdiagnosis and overtreatment is crucial as clinicians focus on optimizing patient selection for renal mass biopsy, active surveillance protocols, and minimally invasive surgery. PATIENT SUMMARY: In this mini-review we discuss the issues of overdiagnosis and overtreatment in patients with kidney cancer. We enumerate the risks of overdiagnosis and overtreatment, and examine the next steps towards preventing these harms.

Partial nephrectomy vs cryoablation for T1a renal cell carcinoma: A comparison of survival benefit stratified by tumour size

OBJECTIVE

We compared the impact on survival outcomes of partial nephrectomy (PN) and cryoablation (CA) for patients diagnosed with T1a renal cell carcinoma (RCC).

PATIENTS AND METHODS

Among patients diagnosed between 2004 and 2014 in the Surveillance, Epidemiology and End Results program, we identified histologically confirmed T1aN0M0 RCC treated with PN (n = 17644) or CA (n = 868). Propensity score matching (PSM) was performed. Kaplan-Meier method, Cox proportional hazards model were used to calculate cancer specific mortality (CSM) and overall mortality (OM) in the unmatched and matched cohort, and in subgroups based on tumour size (< 2 cm, 2-3 cm, 3-4 cm). Sensitivity analyses were performed.

RESULTS

A total of 18512 patients were identified: PN (93.88%) and CA (6.12%). In the propensity-score matched cohort, for tumours ≤ 2 cm, the CA and PN groups had similar CSM (HR: 1.41, 95% CI: 0.32-6.31, p = 0.65) and OM (HR 0.97, 95%CI: 0.47-2.01, p = 0.93). For tumours 2-3 cm, CA was associated with similar CSM (HR 1.64, 95%CI: 0.67-4.03, p = 0.28) but higher OM (HR 2.05, 95%CI: 1.35-3.11, p < 0.001), compared with PN. For tumours 3-4 cm, CA was associated with increased CSM (HR: 3.76, 95% CI: 1.62-8.69, p = 0.002) and OM (HR 2.17, 95%CI: 1.48-3.18, p < 0.001).

CONCLUSION

For RCC ≤ 2 cm, PN and CA are equal in survival outcomes. For RCC 2-4 cm, PN may have a possible advantage over CA.

Personalized Treatment for Small Renal Tumors: Decision Analysis of Competing Causes of Mortality

Purpose To compare the effectiveness of personalized treatment for small (≤4 cm) renal tumors versus routine partial nephrectomy (PN), accounting for various competing causes of mortality. Materials and Methods A state-transition microsimulation model was constructed to compare life expectancy of management strategies for small renal tumors by using 1 000 000 simulations in the following ways: routine PN or personalized treatment involving percutaneous ablation for risk factors for worsening chronic kidney disease (CKD), and otherwise PN; biopsy, with triage of renal cell carcinoma (RCC) to PN or ablation depending on risk factors for worsening CKD; active surveillance for growth; and active surveillance when MRI findings are indicative of papillary RCC. Transition probabilities were incorporated from the literature. Effects of parameter variability were assessed in sensitivity analysis. Results In patients of all ages with normal renal function, routine PN yielded the longest life expectancy (eg, 0.67 years in 65-year-old men with nephrometry score [NS] of 4). Otherwise, personalized strategies extended life expectancy versus routine PN: in CKD stages 2 or 3a, moderate or high NS, and no comorbidities, MRI guidance for active surveillance extended life expectancy (eg, 2.60 years for MRI vs PN in CKD 3a, NS 10); and with Charlson comorbidity index of 1 or more, biopsy or active surveillance for growth extended life expectancy (eg, 2.70 years for surveillance for growth in CKD 3a, NS 10). CKD 3b was most effectively managed by using MRI to help predict papillary RCC for surveillance. Conclusion For patients with chronic kidney disease and small renal tumors, personalized treatment selection likely extends life expectancy. © RSNA, 2019 Online supplemental material is available for this article.

European Association of Urology Guidelines on Renal Cell Carcinoma: The 2019 Update

CONTEXT

The European Association of Urology Renal Cell Carcinoma (RCC) Guideline Panel has prepared evidence-based guidelines and recommendations for the management of RCC.

OBJECTIVE

To provide an updated RCC guideline based on standardised methodology including systematic reviews, which is robust, transparent, reproducible, and reliable.

EVIDENCE ACQUISITION

For the 2019 update, evidence synthesis was undertaken based on a comprehensive and structured literature assessment for new and relevant data. Where necessary, formal systematic reviews adhering to the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines were undertaken. Relevant databases (Medline, Cochrane Libraries, trial registries, conference proceedings) were searched until June 2018, including randomised controlled trials (RCTs) and retrospective or controlled studies with a comparator arm, systematic reviews, and meta-analyses. Where relevant, risk of bias (RoB) assessment, and qualitative and quantitative syntheses of the evidence were performed. The remaining sections of the document were updated following a structured literature assessment. Clinical practice recommendations were developed and issued based on the modified GRADE framework.

EVIDENCE SYNTHESIS

All chapters of the RCC guidelines were updated based on a structured literature assessment, for prioritised topics based on the availability of robust data. For RCTs, RoB was low across studies. For most non-RCTs, clinical and methodological heterogeneity prevented pooling of data. The majority of included studies were retrospective with matched or unmatched cohorts, based on single- or multi-institutional data or national registries. The exception was for the treatment of metastatic RCC, for which there were several large RCTs, resulting in recommendations based on higher levels of evidence.

CONCLUSIONS

The 2019 RCC guidelines have been updated by the multidisciplinary panel using the highest methodological standards. These guidelines provide the most reliable contemporary evidence base for the management of RCC in 2019.

PATIENT SUMMARY

The European Association of Urology Renal Cell Carcinoma Guideline Panel has thoroughly evaluated the available research data on kidney cancer to establish international standards for the care of kidney cancer patients.

Active surveillance for non-muscle invasive bladder cancer

Most of low grade (LG) bladder tumors will experience disease recurrence and very few of them (<2%) will experience disease progression. Therefore active surveillance (AS) for LG non-muscle invasive bladder cancer (NMIBC) has emerged. The goal of our study was to provide a literature review of AS for LG NMIBC including inclusion criteria, modalities and oncological outcomes. We conducted a systematic review (registered in PROSPERO: CRD42018102935) using MEDLINE and EMBASE between June 2018 and August 2018 with the following terms: LG, NMIBC, AS, urothelial neoplasm. Overall, 6 studies that reached our scope of review were included cumulating 403 patients with 2 prospective trials. Inclusion criteria were: recurrent LG (G1 and G2) Ta or T1 NMIBC, with a negative cytology, a low volume (<10 mm) and low number (<5) of tumors. Cystoscopy every 3 months during the first 2 years and every 6 months afterwards were required. AS dropout criteria were presence of tumor-related symptoms, a positive cytology, a modification of tumor morphology or size and patient's request. Pooled data showed an overall 65% reclassification rate where 15% of patients were reclassified based on grade and 10% on stage with a median follow-up of 32 months (IQR, 24-42 months). Only one study reported on progression to MIBC in 4 patients out of 186 (2%). Most of patients enrolled in an AS protocol for recurrent LG NMIBC will undergo a TURBT eventually. Many patients may be eligible to this therapeutic approach but current knowledge does not support its use in daily practice outside of a clinical trial.

Overexpression of FZD1 is Associated with a Good Prognosis and Resistance of Sunitinib in Clear Cell Renal Cell Carcinoma

Frizzled class receptor 1 (FZD1), a receptor for Wnt signaling pathway. Overexpression of FZD1 has been detected in many cancer tissues and cells resulting in tumor development and drug resistance. However, its expression status and prognostic merit in renal cancer still remains unclear. We screened the FZD1 mRNA in clear cell renal cell carcinoma (ccRCC) and papillary renal cell carcinoma (pRCC) from TCGA database and Oncomine database. We then detected FZD1 mRNA expression in sunitinib-resistant cells and the corresponding parental cells by qRT-PCR. FZD1 level was significantly upregulated in renal cancer tissues, renal cancer cell lines and their corresponding sunitinib-resistant cells. FZD1 level was also associated with the clinicopathological characteristics of ccRCC patients that could discriminate metastasis, pathological stage, recurrence and prognosis in ccRCC patients. The Kaplan-Meier survival curve and the log-rank test revealed FZD1 was higher in lower clinical stage and grade that correlated with better overall survival (OS) and disease-free survival (DFS) in total and subgroups of ccRCC patients. Both univariate and multivariate cox regression analysis indicated that high FZD1 level was an independent predictor of good prognosis for OS (HR 0.569, P=0.001) and DFS (HR 0.559, P=0.036) in ccRCC patients. Using cBioportal program, less than 1% mutation in the patients with renal cancer was observed, the alterations in FZD1 were correlated with better OS (P=0.0404) in ccRCC patients. Finally, the result of KEGG pathway analysis predicted seven potential pathways that FZD1 and its related genes got involved in ccRCC, including Hippo signaling pathway. This indicated potential therapeutic targets of ccRCC. In conclusion, our results suggested that expression status of FZD1 had a diagnostic value and prognostic value in ccRCC patients, it also may serve as a potential drug target to relieve sunitinib resistance in renal cancer patients.

Current Management of Small Renal Masses, Including Patient Selection, Renal Tumor Biopsy, Active Surveillance, and Thermal Ablation

Renal cancer represents 2% to 3% of all cancers, and its incidence is rising. The increased use of ultrasonography and cross-sectional imaging has resulted in the clinical dilemma of incidentally detected small renal masses (SRMs). SRMs represent a heterogeneous group of tumors that span the full spectrum of metastatic potential, including benign, indolent, and more aggressive tumors. Currently, no composite model or biomarker exists that accurately predicts the diagnosis of kidney cancer before treatment selection, and the use of renal mass biopsy remains controversial. The management of SRMs has changed dramatically over the last two decades as our understanding of tumor biology and competing risks of mortality in this population has improved. In this review, we critically assess published consensus guidelines and recent literature on the diagnosis and management of SRMs, with a focus on patient treatment selection and use of renal mass biopsy, active surveillance, and thermal ablation. Finally, we highlight important opportunities for leveraging recent research discoveries to identify patients with SRMs at high risk for renal cell carcinoma-related mortality and minimize overtreatment and patient morbidity.

Growth rates and outcomes of observed large renal masses

INTRODUCTION

The natural history of small renal masses has been well defined, leading to the recommendation of active surveillance in some patients with limited life expectancy. However, this information is less clear for large renal masses (LRM), leading to ambiguity for management in the older, comorbid patient. The objective of this study was to define the natural history, including the growth rate and metastatic risk, of LRM in order to better counsel patients regarding active surveillance.

METHODS

This was a retrospective review of patients with solid renal masses >4 cm that had repeated imaging identified from an institutional imaging database. Patient comorbidities and outcomes were obtained through retrospective chart analysis. Outcomes assessed included tumour growth and metastatic rates, as well as cancer-specific (CSS) and overall survival (OS) usimg Kaplan-Meier methodology.

RESULTS

We identified 69 patients between 2005 and 2016 who met the inclusion criteria. Mean age at study entry was 75.5 years; mean tumour maximal dimension at study entry was 5.6 cm. CSS was 83% and OS 63% for patients presenting without metastasis, with a mean followup of 57.5 months. The mean growth rate of those that developed metastasis during followup (n=15) was 0.98 cm/year (95% confidence interval [CI] 0.33-1.63) as compared to those that did not develop metastasis (n=46), with a growth rate of 0.67 cm/year (95% CI 0.34-1) (non-significant). Seven patients had evidence of metastasis at the baseline imaging of their LRM and had subsequent growth rate of 1.47 cm/year (95% CI 0.37-2.57) (non-significant) CONCLUSIONS: Compared to small renal masses, LRM are associated with higher metastasis rates and lower CSS and more rapid growth rates. Selection criteria for recommending observation of LRM in older, comorbid patients should be more conservative than for small renal masses.

Change in Nephrometry Scoring in Small Renal Masses (<4 cm) on Active Surveillance: Preliminary Observations From Tayside Active Surveillance Cohort (TASC) Study

RATIONALE AND OBJECTIVES

Prediction of growth, in particular knowing the possibility of aggressive cancer in small renal masses on active surveillance, remains poorly understood. The study was designed to determine whether serial nephrometry score measurements could predict possibility of aggressive malignancy (grade of cancer) in patients with small renal masses opting for active surveillance initially.

MATERIALS AND METHODS

One hundred sixteen patients between January 2000 and December 2016 undergoing partial nephrectomy were recruited. Out of these, 97 were analyzed using different nephrometry scoring systems. Measurement of nephrometry scores (Radius of tumors, Exo/Endophytic; Nearness of tumors to the collecting system or sinus; Anterior/posterior; Location in relation to polar lines, Preoperative Aspects and Dimensions Used for Anatomical, Centrality Index) was performed by two researchers. Among the patients opting for partial nephrectomy, 40 were on active surveillance for at least 12 months (mean 32; 12-60 months) before partial nephrectomy. Computed tomography scan images of these patients were retrieved and analyzed including comparison to histopathology.

RESULTS

Nephrometry scores measured on serial computed tomography scan images showed a significant correlation between change in score and grade of cancer on multivariate analysis (P value .001). Addition of multivariate analysis to nomogram based on change in size alone did not improve predictive value of area under the curve significantly.

CONCLUSIONS

Change in nephrometry scoring measurements correlates with grade of cancer in small renal masses but falls short of significantly predicting presence of malignancy or grade of cancer on nomogram in patients opting for active surveillance for small renal masses. At present, this approach may be inadequate for decision-making.

RETRACTED: Recommandations françaises du Comité de Cancérologie de l’AFU – Actualisation 2018–2020 : prise en charge du cancer du reinFrench ccAFU guidelines – Update 2018–2020: Management of kidney cancer

This article has been retracted: please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy). Cet article est retiré de la publication à la demande des auteurs car ils ont apporté des modifications significatives sur des points scientifiques après la publication de la première version des recommandations. Le nouvel article est disponible à cette adresse: DOI:10.1016/j.purol.2019.01.004. C’est cette nouvelle version qui doit être utilisée pour citer l’article. This article has been retracted at the request of the authors, as it is not based on the definitive version of the text because some scientific data has been corrected since the first issue was published. The replacement has been published at the DOI:10.1016/j.purol.2019.01.004. That newer version of the text should be used when citing the article.

Conditional survival of patients with small renal masses undergoing active surveillance

OBJECTIVES

To determine conditional survival for patients with small renal masses (SRMs) undergoing active surveillance (AS).

MATERIALS AND METHODS

Patients were enrolled in a prospective AS protocol at our institution between May 2005 and January 2016. Patients with SRMs ≤4 cm with serial cross-sectional imaging available in-house for review were included. Overall survival (OS) was estimated using the Kaplan-Meier method and modelled via Cox proportional hazards models. The primary endpoints analysed were the conditional probability of survival and tumour growth over time. Landmark analysis was used to evaluate survival outcomes beyond the 2-year mark after the initial scan. The relative conditional survival of patients on AS was compared to those undergoing partial nephrectomy (PN) using inverse probability of treatment weighting.

RESULTS

A total of 272 patients were included in this analysis. The mean initial SRM size was 1.74 ± 0.77 cm, and the mean mass size closest to the 2-year mark was 1.97 ± 0.83 cm. The likelihood of continued survival to 5 years improved after the 2-year landmark. Patients with masses <3 cm who survived the first 2 years on AS had a 0.84-0.85 chance of surviving to 5 years, and if they survived 3 years, the probability of surviving to 5 years improved to 0.91. A slow tumour growth (β: 0.12; P < 0.001) with parallel growth rates was found for tumours <3 cm. Patients on AS and those who underwent PN had similar OS for ~7 years, beyond which PN demonstrated a trend of lower risk of death compared with AS (hazard ratio 0.57; P = 0.07).

CONCLUSIONS

The conditional survival probability of patients with SRMs <3 cm on AS increased after 2 years. This information may prove useful to urologists and patients who are considering continuing AS vs intervention after the first 2 years on AS.

Prognostic Value of a Long Non-coding RNA Signature in Localized Clear Cell Renal Cell Carcinoma

BACKGROUND

Long non-coding RNAs (lncRNAs) can be used as prognostic biomarkers in many types of cancer.

OBJECTIVE

We sought to establish an lncRNA signature to improve postoperative risk stratification for patients with localized clear cell renal cell carcinoma (ccRCC).

DESIGN, SETTING, AND PARTICIPANTS

Based on the RNA-seq data of 444 stage I-III ccRCC tumours from The Cancer Genome Atlas project, we built a four-lncRNA-based classifier using the least absolute shrinkage and selection operation (LASSO) Cox regression model in 222 randomly selected samples (training set) and validated the classifier in the remaining 222 samples (internal validation set). We confirmed this classifier in an external validation set of 88 patients with stage I-III ccRCC from a Japan cohort and using quantitative reverse transcription polymerase chain reaction (RT-PCR) in another three independent sets that included 1869 patients from China with stage I-III ccRCC.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Univariable and multivariable Cox regression, Harrell's concordance index (c-index), and time-dependent receiver operating characteristic curves were used to evaluate the association of the classifier with overall survival, disease-specific survival, and disease-free survival.

RESULTS AND LIMITATIONS

Using the LASSO Cox regression model, we built a classifier named RCClnc4 based on four lncRNAs: ENSG00000255774, ENSG00000248323, ENSG00000260911, and ENSG00000231666. In the RNA-seq and RT-PCR data sets, the RCClnc4 signature significantly stratified patients into high-risk versus low-risk groups in terms of clinical outcome across and within subpopulations and remained as an independent prognostic factor in multivariate analyses (hazard ratio range, 1.34 [95% confidence interval {CI}: 1.03-1.75; p=0.028] to 1.89 [95% CI, 1.55-2.31; p<0.001]) after adjusting for clinical and pathologic factors. The RCClnc4 signature achieved a higher accuracy (mean c-index, 0.72) than clinical staging systems such as TNM (mean c-index, 0.62) and the stage, size, grade, and necrosis (SSIGN) score (mean c-index, 0.64), currently reported prognostic signatures and biomarkers for the estimation of survival. When integrated with clinical characteristics, the composite clinical and lncRNA signature showed improved prognostic accuracy in all data sets (TNM + RCClnc4 mean c-index, 0.75; SSIGN + RCClnc4 score mean c-index, 0.75). The RCClnc4 classifier was able to identify a clinically significant number of both high-risk stage I and low-risk stage II-III patients.

CONCLUSIONS

The RCClnc4 classifier is a promising and potential prognostic tool in predicting the survival of patients with stage I-III ccRCC. Combining the lncRNA classifier with clinical and pathological parameters allows for accurate risk assessment in guiding clinical management.

PATIENT SUMMARY

The RCClnc4 classifier could facilitate patient management and treatment decisions.

Imaging Protocols for Active Surveillance in Renal Cell Carcinoma

PURPOSE OF REVIEW

To review the growth kinetics of small renal masses and available imaging modalities for mass characterization and surveillance, highlight current organizational recommendations for the active surveillance of small renal masses, and discuss the most recently reported oncological outcomes of patients as they relate to various surveillance imaging protocols and progression to delayed intervention.

RECENT FINDINGS

Overall, organizational guideline recommendations are broad and lack specifics regarding timing and modality for follow-up imaging of small renal masses. Additionally, despite general consensus in the literature about certain criteria to trigger delayed intervention, there exist no formal guidelines. Active surveillance of small renal masses is an acceptable management strategy for patients with prohibitive surgical risk; however, standardized imaging protocols for surveillance are lacking, as are randomized, prospective trials to evaluate the ideal follow-up protocol.

Comparative effectiveness of management options for patients with small renal masses: a prospective cohort study

OBJECTIVES

To explore the comparative effectiveness of partial nephrectomy (PN), radical nephrectomy (RN), ablative therapies (ablation) and active surveillance (AS) for small renal masses (SRMs; tumour diameter ≤4.0 cm) in the domains of survival, renal function and quality of life (QoL) using the prospectively maintained Delayed Intervention and Surveillance for Small Renal Masses (DISSRM) Registry.

PATIENTS AND METHODS

Estimated glomerular filtration rate (eGFR) was calculated from creatinine values to determine renal function. QoL was measured using the Short Form 12 (SF-12) questionnaire. The Kaplan-Meier method and Cox proportional hazards regression were used for survival analysis. The mixed-effects model was used for renal function and QoL analysis.

RESULTS

Of 638 patients, 231 (36.2%) chose PN, 41 (6.4%) RN, 27 (4.2%) ablation and 339 (53.1%) AS. Cancer-specific survival at 7 years was 98.8% in PN patients and 100% in all other groups. Overall survival (OS) at 7 years was 87.9%, 90.2%, 83.5% and 66.1% in PN, RN, ablation and AS patients, respectively. The OS rate was significantly worse in the AS group than other groups and likely attributable to older age and increased comorbidities. The eGFR was lowest in RN patients but comparable in all other groups. QoL was lowest in AS patients due to lower physical health scores, but mental health scores were similar in all groups.

CONCLUSIONS

With excellent oncological outcomes in all groups, nephron-sparing approaches, like PN and ablation, are preferred over RN when intervention is indicated for SRMs. AS is a reasonable option for select patients, given the comparable oncological and mental health outcomes.

The natural history of large renal masses followed on observation

PURPOSE

The safety and feasibility of active surveillance in comorbid patients with renal masses ≥4.0cm is uncertain. The aim of this study is to describe our institutional experience with the observation of large renal masses.

MATERIALS AND METHODS

One hundred patients were identified with renal masses ≥ 4.0cm that were followed on observation for at least 6 months without surgical intervention between 1994 and 2016. Linear regression was conducted to determine predictors for renal mass growth and competing risk methods were used to estimate the probability of progression in the setting of death from other causes.

RESULTS

Median age at diagnosis was 73 years and 73% of patients had a Charlson Comorbidity index ≥ 4. At presentation, the median mass size was 4.9cm. The median growth rate was 0.4cm/y and there were no significant predictors of growth. Surveillance was discontinued in 34 patients who underwent delayed intervention. Median follow up for metastasis-free survivors was 4 years. In total, 10 patients developed metastatic disease, 3 died from kidney cancer and 30 patients died from other causes. The 5-year probability of other cause mortality was 22% (95% CI: 14%-32%) compared to 6% (95% CI: 2%-13%) for metastatic progression of kidney cancer.

CONCLUSION

In highly comorbid patients, the observation of large renal masses has low likelihood for metastatic progression relative to the risk of nonkidney cancer related death. This data supports the use of surveillance as an acceptable strategy for highly selected patients with competing risks from other serious illnesses.

Treatment approaches to small renal masses in patients of advanced age (≥75 years)

The elderly population is increasing in Turkey and across the world. With the frequent use of imaging modalities, the detection rate of coincidental small renal mass has also increased. Since small renal masses are generally not malignant, most of them can be followed up by active surveillance. In the current study, we examined the treatment options that can be offered to elderly patients with small renal masses. The optimum treatment method for patients of advanced age presenting with renal masses should be determined based on the presence of comorbidities such as age, renal function, and tumor characteristics.

Image-guided minimally invasive treatment for small renal cell carcinoma

Surgical partial nephrectomy is still considered as the "gold standard" for the definitive management of small malignant renal masses, whereas treatment with image-guided percutaneous ablation is still mainly reserved for those patients who cannot undergo nephron-sparing surgical resection due to advanced age, underlying comorbidities or compromised renal function. Nonetheless, the recent evidence that underlines the long-term oncological equipoise of percutaneous ablation methods with surgical resection in combination with the reduced complication rate and cost supports the use of an image-guided minimally invasive approach as a first-line treatment. The purpose of this review is to offer an overview of the most widely used percutaneous renal ablation treatments (radiofrequency, microwave and cryoablation) with a focus on their main technical aspects and application techniques for curative ablation of small renal cell carcinoma (stage cT1a). The authors also provide a critical narrative of the relevant medical literature with an emphasis on outcomes of comparative effectiveness research, and appraise the percutaneous methods compared to surgery in the context of evidence-based practice and future research studies.

TEACHING POINTS

• RCC is a common cancer and is increasingly detected incidentally at early stages. • There is long-term oncological equipoise of percutaneous ablation compared to surgical resection. • Large-scale trials are required to produce Level 1a evidence.

Subtype Differentiation of Small (≤ 4 cm) Solid Renal Mass Using Volumetric Histogram Analysis of DWI at 3-T MRI

OBJECTIVE

The purpose of this article is to evaluate the utility of volumetric histogram analysis of apparent diffusion coefficient (ADC) derived from reduced-FOV DWI for small (≤ 4 cm) solid renal mass subtypes at 3-T MRI.

MATERIALS AND METHODS

This retrospective study included 38 clear cell renal cell carcinomas (RCCs), 16 papillary RCCs, 18 chromophobe RCCs, 13 minimal fat angiomyolipomas (AMLs), and seven oncocytomas evaluated with preoperative MRI. Volumetric ADC maps were generated using all slices of the reduced-FOV DW images to obtain histogram parameters, including mean, median, 10th percentile, 25th percentile, 75th percentile, 90th percentile, and SD ADC values, as well as skewness, kurtosis, and entropy. Comparisons of these parameters were made by one-way ANOVA, t test, and ROC curves analysis.

RESULTS

ADC histogram parameters differentiated eight of 10 pairs of renal tumors. Three subtype pairs (clear cell RCC vs papillary RCC, clear cell RCC vs chromophobe RCC, and clear cell RCC vs minimal fat AML) were differentiated by mean ADC. However, five other subtype pairs (clear cell RCC vs oncocytoma, papillary RCC vs minimal fat AML, papillary RCC vs oncocytoma, chromophobe RCC vs minimal fat AML, and chromophobe RCC vs oncocytoma) were differentiated by histogram distribution parameters exclusively (all p < 0.05). Mean ADC, median ADC, 75th and 90th percentile ADC, SD ADC, and entropy of malignant tumors were significantly higher than those of benign tumors (all p < 0.05). Combination of mean ADC with histogram parameters yielded the highest AUC (0.851; sensitivity, 80.0%; specificity, 86.1%).

CONCLUSION

Quantitative volumetric ADC histogram analysis may help differentiate various subtypes of small solid renal tumors, including benign and malignant lesions.

Role of Active Surveillance for Localized Small Renal Masses

CONTEXT

Stage migration of organ-confined renal masses is occurring as a result of incidental diagnosis, especially in the elderly. Active surveillance (AS) is gaining clinical traction as a treatment alternative to surgery and focal therapy.

OBJECTIVE

To assess contemporary data and evaluate AS risk trade-offs in the treatment of organ-confined kidney cancer.

EVIDENCE ACQUISITION

A comprehensive search of the Embase, Medline and Cochrane databases was carried out. A systematic review of the role of AS for organ-confined renal masses was performed. A total of 28 studies were included in the systematic review.

EVIDENCE SYNTHESIS

The median linear tumor growth rate for clinically localized renal masses (CLRMs) was 0.37cm/yr (interquartile range 0.15-0.7), with 0.22cm/yr in the cT1a subgroup and 0.45cm/yr in the cT1b--2 subgroup. The metastatic progression rate was 1-6% and was similar for cT1a (1-6%) and cT1b (0-5%); other-cause mortality for patients with CLRMs was 0-45% (1-25% for cT1a vs 11-13% for cT1b-2); cancer-specific mortality ranged between 0% and 18%. According to the 2011 Oxford scale, AS as a treatment option for CLRMs remains supported by level 3 evidence.

CONCLUSIONS

Although no randomized clinical data are available, current data support oncologic safety for AS in the management of CLRMs, particularly for small renal masses and among elderly and/or comorbid patients.

PATIENT SUMMARY

In this review we looked at the outcomes for patients with small kidney masses managed with surveillance. We found that surveillance is a safe initial option for tumors of less than 2cm, especially in elderly and sick patients.

Small Renal Masses in Close Proximity to the Collecting System and Renal Sinus Are Enriched for Malignancy and High Fuhrman Grade and Should Be Considered for Early Intervention

INTRODUCTION

Recent reports show a correlation between renal tumor radiographic characteristics and pathologic features. We hypothesize that a more central location within the relatively hypoxic renal medulla might confer a more aggressive tumor phenotype. To test this, radiographic tumor characteristics were compared with tumor grade and histology.

MATERIALS AND METHODS

We retrospectively reviewed renal masses <4 cm in diameter that underwent resection between 2008 and 2013. Tumor location was recorded using standard R.E.N.A.L. Nephrometry Score. Multivariate logistic regression was performed to compare independent anatomic features with incidence of malignancy and high nuclear grade.

RESULTS

A total of 334 renal tumors had information available for analysis. Univariate analysis showed that increasing endophycity and proximity to the collecting system (<4 mm) were predictors of malignancy and high-grade features. In multivariate analysis, proximity to the collecting system <4 mm remained the as the only anatomical variable predictive of malignancy (odds ratio [OR], 3.58; 95% confidence interval [CI], 1.06-12.05; P = .04) and high nuclear grade (OR, 2.81; 95% CI, 1.44-5.51; P = .003).

CONCLUSION

Malignancy and high tumor grade occur with much greater frequency when tumors are located deep in the kidney, in close proximity to the collecting system and renal sinus. Ninety-six percent of small renal masses in this region were cancers and nearly half were Fuhrman Grade 3 or 4, suggesting that these small centrally located tumors should be targeted for early intervention.

Regional Variation of Computed Tomographic Imaging in the United States and the Risk of Nephrectomy

IMPORTANCE

While computed tomography (CT) represents a tremendous advance in diagnostic imaging, it also creates the problem of incidental detection-the identification of tumors unrelated to the clinical symptoms that initiate the test.

OBJECTIVE

To determine the geographic variation in the United States in CT imaging and the corresponding association with one of the most consequential sequelae of incidental detection: nephrectomy.

DESIGN, SETTING, AND PARTICIPANTS

This study is a cross-sectional analysis of age-, sex-, and race-adjusted Medicare data (January 2010-December 2014) from 306 hospital referral regions (HRRs) in the United States and includes information from 15 million fee-for-service Medicare beneficiaries age 65 to 85 years.

EXPOSURES

Regional CT risk (ie, the proportion of the population receiving either a chest or abdominal CT over 5 years).

MAIN OUTCOMES AND MEASURES

Five-year risk of nephrectomy (partial or total).

RESULTS

Data from 15 million fee-for-service Medicare beneficiaries age 65 to 85 years were gathered and illustrate that 43% of Medicare beneficiaries age 65 to 85 years received either a chest or abdominal CT from January 2010 to December 2014. This risk varied across the HRRs, ranging from 31% in Santa Cruz, California, to 52% in Sun City, Arizona. Increased regional CT risk was associated with a higher nephrectomy risk (r = 0.38; 95% CI, 0.28-0.47), particularly among HRRs with more than 50 000 beneficiaries (r = 0.47; 95% CI, 0.31-0.61). After controlling for HRR adult smoking rates, imaging an additional 1000 beneficiaries was associated with 4 additional nephrectomies (95% CI, 3-5). Case-fatality rates for those who underwent nephrectomy were 2.1% at 30 days and 4.3% at 90 days.

CONCLUSIONS AND RELEVANCE

Fee-for-service Medicare beneficiaries are commonly exposed to CT imaging. Those residing in high-scanning regions face a higher risk of nephrectomy, presumably reflecting the incidental detection of renal masses. Additional surgery should be considered one of the risks of excessive CT imaging.

Management of Small Renal Masses

With the ubiquitous use of cross-sectional abdominal imaging in recent years, the incidence of small renal masses (SRMs) has increased, and the evaluation and management of SRMs have become important clinical issues. Diagnosing a mass in the early stages theoretically allows for high rates of cure but simultaneously risks overtreatment. In the past 20 years, surgical treatment of SRMs has transitioned from radical nephrectomy for all renal tumors, regardless of size, to elective partial nephrectomy whenever technically feasible. Additionally, newer approaches, including renal mass biopsy, active surveillance for select patients, and renal mass ablation, have been increasingly used. In this chapter, we review the current evidence-based papers covering aspects of the diagnosis and management of SRMs.

Active Surveillance in Small Renal Masses in the Elderly: A Literature Review

CONTEXT

Small renal masses have become increasingly common due to widespread imaging; however, optimal management of these lesions in the elderly can be complex due to the competing risks of intervention, natural history of disease, patient comorbidities, and expectations. In the properly selected elderly patient, active surveillance remains an accepted and attractive treatment approach.

OBJECTIVE

We completed a literature review of small renal masses (enhancing, <4cm, T1aN0M0 disease) in the elderly, aged ≥70 yr, aimed at identifying the utility of active surveillance in this population. The primary outcomes were conversion to active treatment while on active surveillance and cancer-specific mortality. Secondary outcomes included predictors of treatment, type of treatment performed (partial nephrectomy, radical nephrectomy, and ablation), progression to metastases, all-cause mortality, tumor growth rate, and demographic data including age and Charlson Comorbidity Index.

EVIDENCE ACQUISITION

A comprehensive search of electronic databases (e.g., MEDLINE, EMBASE, SCOPUS, Web of Science, and the Cochrane Library) using search terms "small renal mass" OR "SRM", AND "elderly," "senior," "aging," "geriatric," OR "octogenarian" was completed. All randomized controlled trials, nonrandomized comparison studies, and case series were included and screened by the reviewers. All comparison studies included in the systematic review were assessed for methodological quality using the Cochrane Risk of Bias tools.

EVIDENCE SYNTHESIS

Seventeen primary studies including 36495 patients met the inclusion criteria for the systematic review. All studies were retrospective institutional chart or the Surveillance, Epidemiology, and End Results database reviews. There was a low (4-26%) rate of conversion to active treatment for active surveillance in the identified studies over a follow-up interval of up to 91.5 mo. Overall mortality was substantial in this elderly cohort, with 15-51% of patients being deceased over the course of study follow-up; however, there was minimal cancer-specific mortality due to patients succumbing to alternative comorbid disease. In the future, patient comorbidity and biological age versus the natural history of the individualized tumor biology may play an increasing role in the discussion regarding treatment options and consideration of active surveillance.

CONCLUSIONS

Active surveillance is an effective management strategy in the elderly population. Few patients required the conversion to active treatment and there was low cancer-specific mortality. The majority of patients who expired over the course of the identified studies succumbed to alternative disease. The goal of treatment strategies should include weighing patient-specific prognosis relative to their competing health risks and treatment goals against the natural history of disease and risks of intervention.

PATIENT SUMMARY

In this review article, the authors examined the utility of active surveillance in the setting of a small localized renal mass in the elderly population. Despite being on surveillance, we found that cancer-specific outcomes were excellent, and overall mortality was often a result of comorbid disease. However, there is significant heterogeneity among elderly patients, and treatment approaches should be focused around patient-centered goals and prognosis.

Multiple growth periods predict unfavourable pathology in patients with small renal masses

OBJECTIVE

To use the number of positive growth periods as a characterization of the growth of small renal masses in order to determine potential predictors of malignancy.

PATIENTS AND METHODS

Patients who underwent axial imaging at multiple time points prior to surgical resection for a small renal mass were queried. Patients were categorized based on their pathological tumour grade and stage: favourable (benign, chromophobe and low-grade pT1-2 renal cell carcinoma [RCC]) vs unfavourable (high-grade of any stage and low-grade pT3-4 RCC). A positive growth period was counted each time the difference in greatest tumour diameters between two images was positive. The Cochran-Armitage trend test and Somers' D association were used to determine if the number of positive growth periods was correlated with unfavourable pathology.

RESULTS

Of the 124 patients, 86 (69.4%) had favourable pathology and 38 (30.6%) had unfavourable pathology. Those who had favourable pathology were younger than those who had unfavourable pathology: median (interquartile range [IQR]) 61.0 (52.2-66.0) vs 68.5 (61.5-77.0); P < 0.001. The overall growth rate was higher in the unfavourable group, but was not statistically significant: mean (sd) 0.7 (1.7) vs 1.6 (2.8) cm/year; P = 0.07. There was a significant trend difference in the number of positive growth periods between favourability groups (P = 0.02). An association between increased number of positive growth periods and unfavourable pathology was observed: 0.15 (95% confidence interval 0.02, 0.29). The ratios of favourable to unfavourable pathology were 1.8, 1.0, 0.66, 0.59 and 0 as the number of positive growth periods increased from 0 to 4, respectively.

CONCLUSION

While overall growth rate was not predictive of pathology favourability, there was a positive association between the number of positive growth periods and unfavourable pathology. The number of positive growth periods may be a potential parameter for malignant potential in patients undergoing active surveillance for small renal masses.

Growth kinetics of small renal mass: Initial analysis of active surveillance registry

Purpose

To evaluate the clinical safety and natural history of active surveillance (AS) for incidentally diagnosed small renal mass (SRM).

Materials and Methods

We analyzed prospective data for patients who underwent AS for SRM. From 2010 to 2016, 37 SRMs of less than 3 cm were registered. Computed tomography (CT) and magnetic resonance imaging were used for initial diagnosis and CT, ultrasonography, and chest CT were performed at 6-month intervals. If there was no change in size during 2 years, follow-ups were performed annually. If the growth rate was more than 0.5 cm/y, if the diameter was more than 4 cm, or if clinical progression was observed, we regarded it as progression of SRM and recommended active treatment. We compared the growth rate and clinical course of SRM between patients who remained on surveillance and those who had progressed disease.

Results

The mean age was 63 years (range, 30–86 years) and the mean diameter was 1.8 cm (range, 0.6–2.8 cm) at diagnosis. The mean follow-up period was 27.3 months (range, 6–80 months) and the average growth rate was 0.2 cm/y (range, 0–1.9 cm/y). Six patients (16.2%) showed progression of SRM. Three patients wanted continuous observation, and partial nephrectomy was performed on 3 other patients. None of the patients had clinical progression, including metastasis.

Conclusions

We could delay active treatment for patients with an SRM with scheduled surveillance if the SRM grew relatively slowly. If more long-term AS results are documented for more patients, AS could be an alternative treatment modality for SRM.

Management of the small renal mass

The increasing use of cross-sectional imaging has led to an increase in the diagnosis of incidental small renal masses (SRMs). About 20% of such masses are benign, while a significant proportion of malignant SRMs demonstrate slow growth kinetics and non-aggressive histologic features. Given these characteristics, lesions that were traditionally treated surgically are increasingly managed with less aggressive approaches. Further contributing to the evolving management paradigm is accumulating evidence supporting the safety of active surveillance and the efficacy of percutaneous renal mass biopsy in guiding management decisions. This review first discusses the epidemiology and diagnostic work-up of SRMs. The available management options are then examined, with emphasis placed on the clinical factors considered in selecting an appropriate approach. The existing evidence and long-term outcomes of each strategy are discussed. Finally, an overview of the current paradigm for the management of a patient with a SRM is provided. The goal is to provide physicians with the necessary understanding to appropriately manage this increasingly common condition.

Growth Kinetics of Small Renal Masses on Active Surveillance: Variability and Results from the DISSRM Registry

PURPOSE

Active surveillance is emerging as a safe and effective strategy for the management of small renal masses (4 cm or less). We characterized the growth rate and its pertinence to clinical outcomes in a prospective multi-institutional study of patients with small renal masses.

MATERIALS AND METHODS

Since 2009, the DISSRM (Delayed Intervention and Surveillance for Small Renal Masses) prospective, multi-institutional registry of patients with small renal masses has enrolled patients who elect primary intervention or active surveillance. Patients who elect active surveillance received regularly scheduled imaging and those with 3 or more followup images were included in the current study to evaluate growth rates.

RESULTS

We evaluated 318 patients who elected active surveillance, of whom 271 (85.2%) had 3 or more followup images available with a median imaging followup of 1.83 years. The overall mean ± SD small renal mass growth rate was 0.09 ± 1.51 cm per year (median 0.09) with no variables demonstrating statistically significant associations. The growth rate and variability decreased with longer followup (0.54 and 0.07 cm per year at less than 6 months and greater than 1 year, respectively). No patients had metastatic disease or died of kidney cancer. No statistically significant difference was noted in the growth rate in patients with biopsy demonstrated renal cell carcinoma or in those who died.

CONCLUSIONS

Small renal mass growth kinetics are highly variable early on active surveillance with growth rates and variability decreasing with time. Early in active surveillance, especially during the initial 6 to 12 months, the growth rate is variable and does not reliably predict death or adverse pathological features in the patient subset with available pathology findings. An elevated growth rate may indicate the need for further assessment with imaging or consideration of biopsy prior to progressing to treatment. Additional followup will inform the best clinical pathway for elevated growth rates.

Focal ablation therapy for renal cancer in the era of active surveillance and minimally invasive partial nephrectomy

Partial nephrectomy is the optimal surgical approach in the management of small renal masses (SRMs). Focal ablation therapy has an established role in the modern management of SRMs, especially in elderly patients and those with comorbidities. Percutaneous ablation avoids general anaesthesia and laparoscopic ablation can avoid excessive dissection; hence, these techniques can be suitable for patients who are not ideal surgical candidates. Several ablation modalities exist, of which radiofrequency ablation and cryoablation are most widely applied and for which safety and oncological efficacy approach equivalency to partial nephrectomy. Data supporting efficacy and safety of ablation techniques continue to mature, but they originate in institutional case series that are confounded by cohort heterogeneity, selection bias, and lack of long-term follow-up periods. Image guidance and surveillance protocols after ablation vary and no consensus has been established. The importance of SRM biopsy, its optimal timing, the type of biopsy used, and its role in treatment selection continue to be debated. As safety data for active surveillance and experience with minimally invasive partial nephrectomy are expanding, the role of focal ablation therapy in the treatment of patients with SRMs requires continued evaluation.