Canadian Urological Association guideline: Management of small renal masses - Full-text

Diagnostic accuracy and safety of renal tumour biopsy in patients with small renal masses and its impact on treatment decisions

OBJECTIVE

To assess the safety and diagnostic accuracy of renal tumour biopsy (RTB) in patients with small renal masses (SRM) and to assess if RTB prevents overtreatment in patients with benign SRM.

MATERIAL AND METHODS

In a retrospective, single-centre study from Västmanland, Sweden, 195 adult patients (69 women and 126 men) with SRM ≤ 4 cm who had undergone RTB during 2010-2023 were included. The median age was 70 years (range 23-89). The sensitivity, specificity and predictive values of RTB were calculated using the final diagnosis as the reference standard. Treatment outcomes were recorded for a median 42-month follow-up. Complications following the biopsies were assessed according to the Clavien-Dindo system.

RESULTS

The overall sensitivity of RTB was 95% (95% confidence interval [CI] 90% - 98%) and specificity was 100% (95% CI 95% - 100%). The positive predictive value was 100% and negative predictive value was 92%. The rate of agreement between RTB and the final diagnosis measured using kappa statistics was 0.92. Of the 195 patients, 62 underwent surgery and 48 were treated with ablation. The concordance rate between the RTB histology and final histology after surgery was 89%. Treatment was withheld in 67 of 195 patients with a benign or inconclusive RTB. No patients developed renal cell carcinoma or metastasis during follow-up. Complications occurred in two patients that were classified with Clavien-Dindo grades I and IV.

CONCLUSIONS

Percutaneous renal tumour biopsy appears to be a safe diagnostic method that provides accurate histopathological information about small renal masses and reduces overtreatment of benign SRM.

Cost-Effectiveness Analysis Comparing Biopsy in Advance of Ablation with Concurrent Biopsy and Ablation for Small Renal Masses Measuring 1-3 cm

PURPOSE

To analyze the cost effectiveness of performing a renal mass biopsy in advance of ablation or concurrently with a percutaneous ablation procedure for the management of small renal masses (SRMs).

MATERIALS AND METHODS

A decision-analytic model was developed with a cohort of 65-year-old male patients with an incidental, unilateral 1-3 cm SRM. A decision tree modeled the first year of clinical intervention, after which patients entered a Markov model with a lifetime horizon. Patients were assumed to be treated in accordance with established clinical practice guidelines, including surveillance, repeat ablation for recurrence, and systemic therapy for metastasis. Healthcare cost and utility values were determined from published literature or local hospital estimates, discounted at 1.5%. Total lifetime costs were calculated from the perspective of a Canadian healthcare payer and converted to 2022 Canadian dollars (C$). The primary outcome was incremental cost-effectiveness ratio (ICER) at a willingness-to-pay threshold of C$50,000 per quality-adjusted life year (QALY) gained. The secondary outcome was ICER at a willingness-to-pay threshold of C$50,000 per life year (LY) gained.

RESULTS

Concurrent biopsy and ablation resulted in a gain of 16.4 quality-adjusted days, at an incremental cost of $386, with an ICER of C$8,494/QALY. The concurrent strategy was the dominant strategy for a prevalence of benign mass of <5%. Sequential biopsy and ablation was only cost-effective when LYs were not quality-adjusted and ablation cost was >C$4,300 or benign mass prevalence was >28%.

CONCLUSIONS

Concurrent biopsy and ablation is cost-effective relative to pretreatment diagnostic biopsy for management of incidental SRMs.

Contemporary Management of Renal Cell Carcinoma: A Review for General Practitioners in Oncology

Renal cell carcinoma accounts for a significant proportion of cancer diagnoses in Canadians. Over the past several years, the management of renal cell cancers has undergone rapid changes in all prognostic risk categories, resulting in improved oncologic outcomes. Novel strategies for metastatic disease make use of the synergy between checkpoints and angiogenesis inhibition. Moreover, combination checkpoint inhibition has demonstrated durable efficacy in some patients. Adjuvant immunotherapy has recently shown a survival benefit for the first time in select cases. Significant efforts are underway to explore new compounds or combinations for later-line diseases, such as inhibitors of hypoxia-inducible factors and radiolabeled biomolecules targeting tumor antigens within the neoplastic microenvironment for precise payload delivery. In this manuscript, we provide a comprehensive review of the available data addressing key therapeutic areas pertaining to systemic therapy for metastatic and localized disease, review the most relevant prognostic tools, describe local therapies and management of CNS disease, and discuss practice-changing trials currently underway. Finally, we focus on some of the practical aspects for general practitioners in oncology caring for patients with renal cell carcinoma.

2024 Canadian Urological Association endorsement of an expert report: Kidney involvement in tuberous sclerosis complex

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Avoiding "Needless" nephrectomy: What is the role of small renal mass biopsy in 2024?

Current guidelines do not mandate routine preoperative renal mass biopsy (RMB) for small renal masses (SRMs), which results in a considerable rate (18%-26%) of needless nephrectomy/partial nephrectomy for benign renal tumors. In light of this ongoing practice, a narrative review was conducted to examine the role of routine RMB for SRM. First, arguments justifying the current non-biopsy approach to SRM are critically reviewed and contested. Second, as a standalone procedure, RMB is critically assessed; RMB was found to have higher sensitivity, specificity, and an equal or lower complication rate when compared with other commonly preoperatively biopsied solid organ tumors (e.g., breast, prostate, lung, pancreas, thyroid, and liver). Based on the foregoing information, we propose a paradigm shift in SRM management, advocating for an updated policy in which partial nephrectomy or nephrectomy for SRM invariably occurs only after a preoperative biopsy confirms that a SRM is indeed malignant.

Canadian Association of Radiologists Genitourinary Imaging Referral Guideline

The Canadian Association of Radiologists (CAR) Genitourinary Expert Panel is made up of physicians from the disciplines of radiology, emergency medicine, family medicine, nephrology, and urology, a patient advisor, and an epidemiologist/guideline methodologist. After developing a list of 22 clinical/diagnostic scenarios, a rapid scoping review was undertaken to identify systematically produced referral guidelines that provide recommendations for one or more of these clinical/diagnostic scenarios. Recommendations from 30 guidelines and contextualization criteria in the Grading of Recommendations, Assessment, Development, and Evaluations (GRADE) for guidelines framework were used to develop 65 recommendation statements across the 22 scenarios (2 scenarios point to the CAR Obstetrics and Gynecology Diagnostic Imaging Referral Guideline). This guideline presents the methods of development and the referral recommendations for haematuria, hypertension, renal disease (or failure), renal colic, renal calculi in the absence of acute colic, renal lesion, urinary tract obstruction, urinary tract infection, scrotal mass, or pain, including testicular torsion, adrenal mass, incontinence, urgency, and frequency, chronic pelvic pain, elevated PSA, infertility, and pelvic floor.

Frequency and clinicopathologic features of renal low-grade oncocytic tumour and eosinophilic vacuolated tumour: reclassification of 605 eosinophilic tumours including patients managed with active surveillance

AIMS

Low-grade oncocytic tumour (LOT) and eosinophilic vacuolated tumour (EVT) are recently described emerging entities, which demonstrate distinct features but are not yet recognised as separate neoplasms in the fifth WHO classification. Published series to date have been largely multi-institutional and based on surgically resected tumours. This study aims to determine the frequency, clinicopathologic features and outcome of LOT and EVT in a single institutional series of oncocytic/eosinophilic renal neoplasms, including patients managed with active surveillance and non-surgical intervention.

METHODS AND RESULTS

Cases were identified from a consecutive institutional series of in-house renal tumours diagnosed on biopsy and/or nephrectomy (2003-2023). Tumours with a diagnosis or differential diagnosis of oncocytoma, chromophobe renal cell carcinoma or oncocytic neoplasm not otherwise specified (including LOT, EVT and tumours with overlapping hybrid features) were retrospectively reviewed and classified/reclassified.In total, 605 oncocytic/eosinophilic renal neoplasms were reviewed, among which 33 LOT (5.5%) and 5 EVT (0.8%) were identified. LOT were CK7+, CD117- and GATA3+ (94%). EVT were CD117+, CK7 focal+ (80%) and cathepsin K+ (80%). At the median follow-up of 34 months (range 2-253) and 56 months (range 8-90) for LOT and EVT, respectively, there was no evidence of recurrence following ablation/surgical resection, metastasis or death from disease for all patients, including the 22 managed with active surveillance (20 LOT and 2 EVT).

CONCLUSIONS

LOT and EVT comprised a minority of oncocytic renal neoplasms in this series. We report a large institutional series including patients managed non-surgically, with no adverse outcome, adding to the existing literature indicating a benign outcome.

Adequacy of clinical guideline recommendations for patients with low-risk cancer managed with monitoring: systematic review

OBJECTIVES

The aim of this systematic review was to summarize national and international guidelines that made recommendations for monitoring patients diagnosed with low-risk cancer. It appraised the quality of guidelines and determined whether the guidelines adequately identified patients for monitoring, specified which tests to use, defined monitoring intervals, and stated triggers for further intervention. It then assessed the evidence to support each recommendation.

STUDY DESIGN AND SETTING

Following the Preferred Reporting Items for Systematic Reviews and Meta-analyses, we searched PubMed and Turning Research into Practice databases for national and international guidelines' that were written in English and developed or updated between 2012 and 2023. Quality of individual guidelines was assessed using the AGREE II tool.

RESULTS

Across the 41 published guidelines, 48 different recommendations were identified: 15 (31%) for prostate cancer, 11 (23%) for renal cancer, 6 (12.5%) for thyroid cancer, and 10 (21%) for blood cancer. The remaining 6 (12.5%) were for brain, gastrointestinal, oral cavity, bone and pheochromocytoma and paraganglioma cancer. When combining all guidelines, 48 (100%) stated which patients qualify for monitoring, 31 (65%) specified which tests to use, 25 (52%) provided recommendations for surveillance intervals, and 23 (48%) outlined triggers to initiate intervention. Across all cancer sites, there was a strong positive trend with higher levels of evidence being associated with an increased likelihood of a recommendation being specific (P = 0.001) and the evidence for intervals was based on expert opinion or other guidance.

CONCLUSION

With the exception of prostate cancer, the evidence base for monitoring low-risk cancer is weak and consequently recommendations in clinical guidelines are inconsistent. There is a lack of direct evidence to support monitoring recommendations in the literature making guideline developers reliant on expert opinion, alternative guidelines, or indirect or nonspecific evidence.

Papillary renal neoplasm with reverse polarity is biologically and clinically distinct from eosinophilic papillary renal cell carcinoma

Papillary renal neoplasm with reverse polarity (PRNRP) is a recently described indolent entity with distinct features and its recognition from other oncocytic/eosinophilic papillary renal cell carcinoma (ePRCC) has important prognostic implications. ABCC2, a renal drug transporter, is overexpressed in aggressive PRCCs. In this study, we compared the clinicopathological parameters and the biological ABCC2 expression between PRNRP and ePRCC. PRNRP (n = 8) and ePRCC (n = 21) cases were selected from resection specimens and corresponding clinicopathological data were collected. ABCC2 immunohistochemical (IHC) staining was performed and ABCC2 staining patterns were classified as negative, cytoplasmic, and brush-border. RNA in-situ hybridization (ISH) was used to assess ABCC2 transcript levels. All eight PRNRP cases had weak cytoplasmic ABCC2 IHC reactivity; however, they showed no detectable ABCC2 transcripts on RNA ISH. In comparison, 76% (16/21) of ePRCCs showed ABCC2 IHC brush-border expression and significantly higher ABCC2 RNA ISH transcript levels (p < 0.001). Additionally, the ePRCC group showed a significantly larger tumor size (p = 0.004), higher WHO/ISUP grade (p < 0.001), and stage (p = 0.044). None of the PRNRP cases showed disease progression, while 9.5% (2/21) ePRCCs had disease progression. PRNRP is clinically and biologically distinct from ePRCC. Hence, it is crucial to differentiate between these two entities, particularly in needle core biopsies.

Percutaneous microwave ablation of T1a renal cell carcinomas: A 10-year single-center retrospective review

INTRODUCTION

Partial nephrectomy is currently the preferred treatment option for T1a renal cell carcinomas (RCC), with nephron-sparing techniques, including microwave ablation, becoming more common in select patients. Primary aims are to document outcomes of microwave ablation for T1a RCCs in an Australian tertiary centre to add to the evidence for its safety and efficacy.

METHODS

The prospectively maintained Sir Charles Gairdner Hospital Interventional Radiology database was retrospectively searched for all Renal Microwave ablations completed between June 2012 and February 2022. This database and a combination of hospital programmes including Agfa Impax PACS, Bossnet digital medical record and iSoft Clinical Manager were used to extract the relevant data which was anonymized and entered into an Excel spreadsheet for analysis.

RESULTS

Forty-eight patients underwent microwave ablation for 50 tumours. Of these, there were two local and two distant recurrences. A fifth patient had metastases on presentation. Higher local recurrence rates were associated with larger tumour size (P = 0.043). Tumour proximity to the collecting system <4 mm was associated with higher rates of complications (P = 0.020). RENAL scores did not show statistically significant correlation with complications (P = 0.092) or local or distant recurrence. Notably, the study follow-up time was longer than many comparative studies (mean = 2796, ~7.66 years censoring for death and mean = 832 days, ~2.28 years not censoring for death).

CONCLUSION

Consistent with the literature, this study further demonstrates that microwave ablation is a safe and efficacious option for treatment of T1a RCC.

The impact of robotic surgery access on the management of patients with clinical stage I kidney tumors

INTRODUCTION

Robotic surgery is used in the treatment of kidney tumors. We aimed to determine if robotic access was associated with initial choice of management for patients with a clinical stage I kidney mass.

METHODS

Patients with a clinical stage I kidney mass were identified from the Canadian Kidney Cancer information system (CKCis) cohort. Sites were classified by year and access to robotic surgery. Associations between robotic access and initial management were determined using logistic regression. Univariable and multivariable analyses were performed, adjusting for tumor size and stage, and presented as relative risks (RR ) or adjusted RR (aRR) and 95% confidence intervals (CI).

RESULTS

Overall, 4160 patients were included. Among patients treated with surgery, the proportion of partial nephrectomy compared to radical nephrectomy was significantly higher in robotic sites (77.3% for robotic sites vs. 65.9% for non-robotic sites; RR 1.17, 95% CI 1.12-1.23, p<0.0001; aRR 1.12, 95% CI 1.08-1.17, p<0.0001). Patients receiving partial nephrectomy at sites with robotic access were more likely to receive a minimally invasive approach compared to patients at non-robotic sites (61.4% vs. 50.9%, RR 1.21, 95% CI 1.12-1.30; aRR 1.16, 95% CI 1.08-1.25, p<0.0001). The proportion of patients managed by active surveillance was not significantly different between robotic (405, 16.9%) and non-robotic (258, 14.7%) sites (RR 1.15, 95% CI 0.99-1.32; aRR 0.97, 95% CI 0.84-1.12).

CONCLUSIONS

Access to robotic kidney surgery was associated with increased use of partial nephrectomy and minimally invasive partial nephrectomy. Use of active surveillance was similar at robotic and non-robotic institutions. Limitations of this study include lack of data on perioperative complications and cancer recurrence.

A Predictive Model for Kidney Failure After Nephrectomy for Localized Kidney Cancer: The Kidney Cancer Risk Equation

RATIONALE & OBJECTIVE

Nephrectomy is the mainstay of treatment for individuals with localized kidney cancer. However, surgery can potentially result in the loss of kidney function or in kidney failure requiring dialysis/kidney transplantation. There are currently no clinical tools available to preoperatively identify which patients are at risk of kidney failure over the long term. Our study developed and validated a prediction equation for kidney failure after nephrectomy for localized kidney cancer.

STUDY DESIGN

Population-level cohort study.

SETTING & PARTICIPANTS

Adults (n=1,026) from Manitoba, Canada, with non-metastatic kidney cancer diagnosed between January 1, 2004, and December 31, 2016, who were treated with either a partial or radical nephrectomy and had at least 1 estimated glomerular filtration rate (eGFR) measurement before and after nephrectomy. A validation cohort included individuals in Ontario (n=12,043) with a diagnosis of localized kidney cancer between October 1, 2008, and September 30, 2018, who received a partial or radical nephrectomy and had at least 1 eGFR measurement before and after surgery.

NEW PREDICTORS & ESTABLISHED PREDICTORS

Age, sex, eGFR, urinary albumin-creatinine ratio, history of diabetes mellitus, and nephrectomy type (partial/radical).

OUTCOME

The primary outcome was a composite of dialysis, transplantation, or an eGFR<15mL/min/1.73m2 during the follow-up period.

ANALYTICAL APPROACH

Cox proportional hazards regression models evaluated for accuracy using area under the receiver operating characteristic curve (AUC), Brier scores, calibration plots, and continuous net reclassification improvement. We also implemented decision curve analysis. Models developed in the Manitoba cohort were validated in the Ontario cohort.

RESULTS

In the development cohort, 10.3% reached kidney failure after nephrectomy. The final model resulted in a 5-year area under the curve of 0.85 (95% CI, 0.78-0.92) in the development cohort and 0.86 (95% CI, 0.84-0.88) in the validation cohort.

LIMITATIONS

Further external validation needed in diverse cohorts.

CONCLUSIONS

Our externally validated model can be easily applied in clinical practice to inform preoperative discussions about kidney failure risk in patients facing surgical options for localized kidney cancer.

PLAIN-LANGUAGE SUMMARY

Patients with localized kidney cancer often experience a lot of worry about whether their kidney function will remain stable or will decline if they choose to undergo surgery for treatment. To help patients make an informed treatment decision, we developed a simple equation that incorporates 6 easily accessible pieces of patient information to predict the risk of reaching kidney failure 5 years after kidney cancer surgery. We expect that this tool has the potential to inform patient-centered discussions tailored around individualized risk, helping ensure that patients receive the most appropriate risk-based care.

Endophytic to total tumour volume ratio: An added variable to patients with T1b/T2 renal tumours undergoing partial nephrectomy

INTRODUCTION

Partial nephrectomy is the standard of care to patients with small renal masses. It is still encouraged to larger tumours whenever feasible. The aim of this study is to look for the endophytic to total tumour volume ratio as an added variable to study the complexity of partial nephrectomy to patients with T1b/ T2 renal tumours.

METHODS

Retrospective data collection of patients that had partial nephrectomy for T1b/T2 renal tumours by a single surgeon was done. Radiological re-assessment for the CT images to measure the endophytic to total tumour volume ratio was done.

RESULTS

The mean age of the patients was 63 years. The study included 25 males and 11 females. All cases were managed by open surgery using retroperitoneal transverse lateral lumbotomy and warm ischemia was used in all patients. The mean tumour volume was 74 cc, the mean endophytic tumour volume was 29 cc. The mean percentage of endophytic to total tumour volume was 42%.

CONCLUSIONS

Partial nephrectomy is safe for most of the patients with good performance status, having large renal masses. More complex surgery can be predicted in patients with endophytic to total tumour volume greater than 42%.

The Changing Role of Renal Mass Biopsy

The incidence and prevalence of small renal masses (SRMs) continues to rise and with increased detection comes increases in surgical management, although the probability of an SRM being benign is upward of 30%. An extirpative treatment first diagnose-later strategy persists and clinical tools for risk stratification such as renal mass biopsy remain severely underutilized. The overtreatment of SRMs has multiple detrimental effects including surgical complications, psychosocial stress, financial loss, and reduced renal function leading to downstream effects such as the need for dialysis and cardiovascular disease.

Small Renal Masses: The Evolving Histologic, Imaging, and Genomic Landscapes

According to the American Cancer Society, it is currently estimated that approximately 81,800 new cases of kidney cancer will be diagnosed in the United States in 2023 [...].