Utilization of Renal Mass Biopsy for T1 Renal Lesions across Michigan: Results from MUSIC-KIDNEY, A Statewide Quality Improvement Collaborative

The evolving management of small renal masses

Small renal masses (SRMs) are a heterogeneous group of tumours with varying metastatic potential. The increasing use and improving quality of abdominal imaging have led to increasingly early diagnosis of incidental SRMs that are asymptomatic and organ confined. Despite improvements in imaging and the growing use of renal mass biopsy, diagnosis of malignancy before treatment remains challenging. Management of SRMs has shifted away from radical nephrectomy, with active surveillance and nephron-sparing surgery taking over as the primary modalities of treatment. The optimal treatment strategy for SRMs continues to evolve as factors affecting short-term and long-term outcomes in this patient cohort are elucidated through studies from prospective data registries. Evidence from rapidly evolving research in biomarkers, imaging modalities, and machine learning shows promise in improving understanding of the biology and management of this patient cohort.

[Nephron sparing in the management of localized solid renal mass]

Managing a malignant renal tumor requires, first of all, a reflection on the necessity of its treatment. It must consider the renal function, altered at the time of diagnosis in 50% of cases. The treatment method chosen depends on many factors, in particular, the predicted residual renal function, the risk of chronic kidney disease, the need for temporary or long-term dialysis, and overall long-term survival. Other factors include the size, position, and number of tumors and a hereditary tumor background. When a renal-sparing management alternative is available, total nephrectomy should no longer be performed in patients with small malignant renal masses (cT1a). This may consist of surgery (partial nephrectomy or lumpectomy), percutaneous thermo-ablation (by radiofrequency, microwave, or cryotherapy). In patients with limited life expectancy, imaging-based surveillance may be proposed to suggest treatment in case of local progression. Good coordination between urologist, radiologist, nephrologist, and sometimes radiotherapist should allow optimal management of patients with a malignant renal tumor with or without underlying renal failure.

Diagnostic Biopsy for Small Renal Tumours: A Survey of Current European Practice

Background and objective

Renal tumour biopsy (RTB) can help in risk stratification of renal tumours with implications for management, but its utilisation varies. Our objective was to report current practice patterns, experiences, and perceptions of RTB and research gaps regarding RTB for small renal masses (SRMs).

Methods

Two web-based surveys, one for health care providers (HCPs) and one for patients, were distributed via the European Association of Urology Young Academic Urologist Renal Cancer Working Group and the European Society of Residents in Urology in January 2023.

Key findings and limitations

The HCP survey received 210 responses (response rate 51%) and the patient survey 54 responses (response rate 59%). A minority of HCPs offer RTB to >50% of patients (14%), while 48% offer it in <10% of cases. Most HCPs reported that RTB influences (61.5%) or sometimes influences (37.1%) management decisions. Patients were more likely to favour active treatment if RTB showed high-grade cancer and less likely to favour active treatment for benign histology. HCPs identified situations in which they would not favour RTB, such as cystic tumours and challenging anatomic locations. RTB availability (67%) and concerns about delays to treatment (43%) were barriers to offering RTB. Priority research gaps include a trial demonstrating that RTB leads to better clinical outcomes, and better evidence that benign/indolent tumours do not require active treatment.

Conclusions and clinical implications

Utilisation of RTB for SRMs in Europe is low, even though both HCPs and patients reported that RTB results can affect disease management. Improving timely access to RTB and generating evidence on outcomes associated with RTB use are priorities for the kidney cancer community.

Patient summary

A biopsy of a kidney mass can help patients and doctors make decisions on treatment, but our survey found that many patients in Europe are not offered this option. Better access to biopsy services is needed, as well as more research on what happens to patients after biopsy.

Building a Roadmap for Surveillance of Renal Masses Using a Modified Delphi Method to Help Achieve Consensus

OBJECTIVE

To establish a consensus for initial evaluation and follow-up of patients on active surveillance (AS) for T1 renal masses (T1RM).

METHODS

A modified Delphi method was used to gather information about AS of T1RM, with a focus on patient selection, timing/type of imaging modality, and triggers for intervention. A consensus panel of Michigan Urological Surgery Improvement Collaborative-affiliated urologists who routinely manage renal masses was formed. Areas of consensus (defined >80% agreement) about T1RM AS were established iteratively via 3 rounds of online questionnaires.

RESULTS

Twenty-six Michigan Urological Surgery Improvement Collaborative urologists formed the panel. Consensus was achieved for 321/587 scenarios (54.7%) administered through 124 questions. Life expectancy, age, comorbidity, and renal function were most important for patient selection, with life expectancy ranking first. All tumors <3 cm and all patients with life expectancy <1 year were considered appropriate for AS. Appropriateness also increased with elevated perioperative risk, increasing tumor complexity, and/or declining renal function. Consensus was for multiphasic axial imaging initially (contrast CT for GFR >60 or MRI for GFR >30) with first repeat imaging at 3-6 months and subsequent imaging timing determined by tumor size. Consensus was for chest imaging for tumors >3 cm initially and >5 cm at follow up. Renal biopsy was not felt to be a requirement for entering AS, but useful in several scenarios. Consensus indicated rapid tumor growth as an appropriate trigger for intervention.

CONCLUSION

Our consensus panel was able to achieve areas of consensus to help define a clinically useful and specific roadmap for AS of T1RM and areas for further discussion where consensus was not achieved.

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.