Incidental discovery of metastatic renal cell carcinoma at the vaginal wall: A case report.

Metastasis of renal cell carcinoma (RCC) to the vaginal wall has rarely been reported in the literature. We present a case of a 48-year-old who was found to have a solitary RCC metastasis at the vaginal wall, five years following radical nephrectomy. This case is noteworthy because this late presentation is unique, with prior reports of synchronous metastasis or metastasis within two years of nephrectomy, highlighting the need to consider metastatic RCC to the vagina a possibility even many years after treatment.

Variation in management of lymph node positive prostate cancer after radical prostatectomy within a statewide quality improvement consortium.

BACKGROUND: Patients with lymph node positive (pN+) disease found at the time of radical prostatectomy with pelvic lymphadenectomy for clinically localized prostate cancer (CaP) are at high risk of disease persistence and progression. Contemporary management trends of pN+ CaP are not well described. MATERIALS AND METHODS: Patients in the Michigan Urologic Surgery Improvement Collaborative (MUSIC) with clinically localized prostate cancer who underwent radical prostatectomy between 2012 and 2023 with cN0/pN+ disease were identified. The primary outcome was to evaluate patient and practice-level factors associated with time to secondary post-RP treatment. Secondary outcomes included practice-level variation in management of pN+ CaP and rates of secondary treatment modality. To assess factors associated with secondary treatment, a Cox proportional hazards model of a 60-day landmark analysis was performed. RESULTS: We identified 666 patients with pN+ disease. Overall, 66% underwent secondary treatment within 12 months post-RP. About 19% of patients with detectable post-RP PSA did not receive treatment. Of patients receiving secondary treatment after 60-days post-RP, 34% received androgen deprivation therapy (ADT) alone, 27% received radiation (RT) alone, 36% received combination, and 4% received other systemic therapies. In the multivariable model, pathologic grade group (GG)3 (HR 1.5; 95%CI: 1.05-2.14), GG4-5 (HR 1.65; 95%CI: 1.16-2.34), positive margins (HR 1.46; 95%CI: 1.13-1.88), and detectable postoperative PSA ≥0.1 ng/ml (HR 3.46; 95%CI: 2.61-4.59) were significantly associated with secondary post-RP treatment. There was wide variation in adjusted practice-level 12-month secondary treatment utilization (28%-79%). CONCLUSIONS: The majority pN+ patients receive treatment within 12 months post-RP which was associated with high-risk pathological features and post-RP PSA. Variation in management of pN+ disease highlights the uncertainty regarding the optimal management. Understanding which patients will benefit from secondary treatment, and which type, will be critical to minimize variation in care.

Conversion to Radical Nephrectomy From Robotic Partial Nephrectomy Is Most Commonly Due to Anatomic and Oncologic Complexity.

PURPOSE: Partial nephrectomy is standard-of-care treatment for small renal masses. As utilization of partial nephrectomy increases and includes larger and complex tumors, the risk of conversion to radical nephrectomy likely increases. We evaluated incidence and reason for conversion to radical nephrectomy in patients scheduled for partial nephrectomy by surgeons participating in MUSIC (the Michigan Urologic Surgery Improvement Collaborative). MATERIALS AND METHODS: All patients in whom robotic partial nephrectomy was planned were stratified by completed procedure (robotic partial nephrectomy vs radical nephrectomy). Preoperative and intraoperative records were reviewed for preoperative assessment of difficulty and reason for conversion. Patient, tumor, pathologic, and practice variables were compared between cohorts. RESULTS: Of 650 patients scheduled for robotic partial nephrectomy, conversion to radical nephrectomy occurred in 27 (4.2%) patients. No conversions to open were reported. Preoperative documentation indicated a plan for possible conversion in 18 (67%) patients including partial with possible radical (n = 8), partial vs radical (n = 6), or likely radical nephrectomy (n = 4). Intraoperative documentation indicated that only 5 (19%) conversions were secondary to bleeding, with the remaining conversions due to tumor complexity and/or oncologic concerns. Patients undergoing conversion had larger (4.7 vs 2.8 cm, P < .001) and higher-complexity tumors (64% vs 6%, P < .001) with R.E.N.A.L. (for radius, exophytic/endophytic, nearness of tumor to collecting system, anterior/posterior, location relative to polar line) nephrometry score ≥ 10. The converted cases had a higher rate of ≥ pT3 (27% vs 8.4%, P = .008). CONCLUSIONS: There was a low rate of conversion from robotic partial to radical nephrectomy in the MUSIC-KIDNEY (Kidney mass: Identifying and Defining Necessary Evaluation and therapY) collaborative, and an even lower risk of conversion due to uncontrolled bleeding. Targeted review of each conversion identified appropriate decision-making based on oncologic risk in most cases.

More Than Words: Defining Adjuvant, Consolidative, and Salvage Treatment after Radical Prostatectomy.

After radical prostatectomy, adjuvant therapy should be used sparingly when prostate-specific antigen (PSA) is undetectable. Instead, early salvage therapy is recommended for PSA recurrence. Patients with PSA persistence after prostatectomy are at high risk and should be offered consolidative therapy.

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.

Simplified cardiovascular index may be the best comorbidity index for clinical use in prediction of mortality for renal cancer patients.

OBJECTIVE: Understanding the relationship between comorbidities and life expectancy is important in cancer patients who carry risks of cancer and noncancer-related mortality. Comorbidity indices (CI) are tools to provide an objective measure of competing risks of death. We sought to determine which CI might be best incorporated into clinical practice for patients with suspected renal cancer. MATERIALS AND METHODS: 1572 patients diagnosed with renal masses (stage I-IV) between 1998 and 2016 were analyzed for this study. Patient data were gathered from a community-based health center. Comorbidities were evaluated individually, and with 1 of 4 CI: Charlson (CCI), updated CCI (uCCI), age-adjusted CCI (aCCI), and simplified cardiovascular index (CVI). Cox-proportional hazard analysis of all-cause mortality was performed using the four CI, adjusting for the 4 CI, adjusting for age, gender, race, tumor size, and tumor stage. RESULTS: Univariable analyses revealed the four CI were significant predictors of mortality (P < 0.05), as were age, gender, tumor size, and stage. Comorbid conditions at diagnosis included hypertension (47.8%), diabetes mellitus (47.2%), coronary artery disease (41.1%), chronic kidney disease (31.8%), peripheral vascular disease (8.0%), congestive heart failure (5.7%), chronic obstructive pulmonary disease (5.7%), and cerebrovascular disease (2.0%). When analyzing the 4 CI in multivariable survival analyses accounting for factors available at diagnosis, and analyses incorporating pathologic and recurrence data, only CVI score and uCCI remained statistically significant (P < 0.05). Limitations of this work are the retrospective nature of data collection and data from a single institution, limiting the generalizability. CONCLUSION: Increasing comorbidity, age, tumor size, and cM stage are predictors of ACM for suspected renal cancer patients. CVI appears to provide comparable information to various iterations of CCI (uCCI, aCCI) while being the simplest to use. Utilization of CVI may assist clinicians and patients when considering between interventional and noninterventional approaches for suspected renal cancer.

Practice-Level Variation in Opioid-Free Discharge Following Surgery for T1 Renal Masses: A MUSIC-KIDNEY Analysis.

INTRODUCTION: Opioid prescription following surgery has played a role in the current opioid epidemic. We evaluated practice-level variation in opioid prescribing following surgery for cT1 renal masses and examined the relationships between opioid-free discharge and postoperative emergency department (ED) visits and readmissions. METHODS: We retrospectively examined all T1 renal mass (RM) patients with data regarding postoperative opioid prescriptions within the Michigan Urological Surgery Improvement Collaborative-Kidney Mass: Identifying and Defining Necessary Evaluation and Therapy (MUSIC-KIDNEY) registry from April 2021 to March 2023. Patients were stratified into those who received opioids at discharge and those with opioid-free discharge. Associations with patient, tumor, and surgical factors were evaluated. Rates of postoperative ED visits and readmissions within 30 days were compared between cohorts. Practice-level variation was assessed. RESULTS: Of 414 patients who underwent surgery for T1 RM across 15 practices in MUSIC-KIDNEY, 23.7% had opioid-free discharge. Practice-level variation in rates of opioid-free discharge ranged from 6.7% to 55.0%. For patients prescribed opioids, the median number of pills was 10 (IQR 6-12). Patients with cT1b masses were more likely to have opioid-free discharge (44.9% vs 32%, OR 0.44; 95% CI 0.22-0.89). Rates of 30-day ED visits (7.0% vs 3.1%) and readmissions (4.1% vs 2.0%) were lower in the opioid-free discharge group but did not reach statistical significance. CONCLUSIONS: MUSIC-KIDNEY data suggest opioid-free discharge is not associated with increased rates of postoperative ED visits or readmissions. There exists wide practice-level variation in opioid prescriptions following surgery for T1 RM in the state of Michigan. Similar variation likely exists throughout the United States, and best surgical practice suggests reduction in opioid prescribing after nephrectomy.

Can MRI Help Inform Which Men With a History of Multifocal High-Grade Prostatic Intraepithelial Neoplasia or Atypical Small Acinar Proliferation Remain at an Elevated Risk for Clinically Significant Prostate Cancer?

PURPOSE: We investigated the association of MRI findings in men with a previous diagnosis of atypical small acinar proliferation (ASAP) or multifocal high-grade intraepithelial neoplasia (HGPIN) with pathologic findings on repeat biopsy. MATERIALS AND METHODS: We retrospectively reviewed patients with ASAP/multifocal HGPIN undergoing a repeat biopsy in the Michigan Urological Surgery Improvement Collaborative registry. We included men with and without an MRI after the index biopsy demonstrating ASAP/multifocal HGPIN but before the repeat biopsy. Men with an MRI prior to the index biopsy were excluded. We compared the proportion of men with ≥ GG2 CaP (Grade Group 2 prostate cancer) on repeat biopsy among the following groups with the χ2 test: no MRI, PIRADS (Prostate Imaging-Reporting and Data System) ≥ 4, and PIRADS ≤ 3. Multivariable models were used to estimate the adjusted association between MRI findings and ≥ GG2 CaP on repeat biopsy. RESULTS: Among the 207 men with a previous diagnosis of ASAP/multifocal HGPIN that underwent a repeat biopsy, men with a PIRADS ≥ 4 lesion had a higher proportion of ≥ GG2 CaP (56%) compared with men without an MRI (12%, P < .001). A lower proportion of men with PIRADS ≤ 3 lesions had ≥ GG2 CaP (3.0%) compared with men without an MRI (12%, P = .13). In the adjusted model, men with a PIRADS 4 to 5 lesion had higher odds (OR: 11.4, P < .001) of ≥ GG2 CaP on repeat biopsy. CONCLUSIONS: MRI is a valuable diagnostic tool to triage which men with a history of ASAP or multifocal HGPIN on initial biopsy should undergo or avoid repeat biopsy without missing clinically significant CaP.

Interruptions in bladder cancer care during the COVID-19 public health emergency.

BACKGROUND: Academic and community urology centers participating in a pragmatic clinical trial in non-muscle-invasive bladder cancer completed monthly surveys assessing restrictions in aspects of bladder cancer care due to the COVID-19 Public Health Emergency. Our objective was to describe pandemic-related restrictions on bladder cancer care. METHODS: We invited 32 sites participating in a multicenter pragmatic bladder cancer trial to complete monthly surveys distributed through REDCap beginning in May 2020. These surveys queried sites on whether they were experiencing restrictions in the use of elective surgery, transurethral resection of bladder tumors (TURBT), radical cystectomy, office cystoscopy, and intravesical bacillus Calmette-Guerin (BCG) availability. Responses were collated with descriptive statistics. RESULTS: Of 32 eligible sites, 21 sites had at least a 50% monthly response rate over the study period and were included in the analysis. Elective surgery was paused at 76% of sites in May 2020, 48% of sites in January 2021, and 52% of sites in January 2022. Over those same periods, coinciding with COVID-19 incidence waves, TURBT was restricted at 10%, 14%, and 14% of sites, respectively, radical cystectomy was restricted at 10%, 14%, and 19% of sites, respectively, and cystoscopy was restricted at 33%, 0%, and 10% of sites, respectively. CONCLUSIONS: Bladder cancer care was minimally restricted compared with more pronounced restrictions seen in general elective surgeries during the COVID-19 pandemic.

Development of a novel score (RENSAFE) to determine probability of acute kidney injury and renal functional decline post surgery: A multicenter analysis.

OBJECTIVE: To create and validate 2 models called RENSAFE (RENalSAFEty) to predict postoperative acute kidney injury (AKI) and development of chronic kidney disease (CKD) stage 3b in patients undergoing partial (PN) or radical nephrectomy (RN) for kidney cancer. METHODS: Primary objective was to develop a predictive model for AKI (reduction >25% of preoperative eGFR) and de novo CKD≥3b (<45 ml/min/1.73m2), through stepwise logistic regression. Secondary outcomes include elucidation of the relationship between AKI and de novo CKD≥3a (<60 ml/min/1.73m2). Accuracy was tested with receiver operator characteristic area under the curve (AUC). RESULTS: AKI occurred in 452/1,517 patients (29.8%) and CKD≥3b in 116/903 patients (12.8%). Logistic regression demonstrated male sex (OR = 1.3, P = 0.02), ASA score (OR = 1.3, P < 0.01), hypertension (OR = 1.6, P < 0.001), R.E.N.A.L. score (OR = 1.2, P < 0.001), preoperative eGFR<60 (OR = 1.8, P = 0.009), and RN (OR = 10.4, P < 0.0001) as predictors for AKI. Age (OR 1.0, P < 0.001), diabetes mellitus (OR 2.5, P < 0.001), preoperative eGFR <60 (OR 3.6, P < 0.001) and RN (OR 2.2, P < 0.01) were predictors for CKD≥3b. AUC for RENSAFE AKI was 0.80 and 0.76 for CKD≥3b. AKI was predictive for CKD≥3a (OR = 2.2, P < 0.001), but not CKD≥3b (P = 0.1). Using 21% threshold probability for AKI achieved sensitivity: 80.3%, specificity: 61.7% and negative predictive value (NPV): 88.1%. Using 8% cutoff for CKD≥3b achieved sensitivity: 75%, specificity: 65.7%, and NPV: 96%. CONCLUSION: RENSAFE models utilizing perioperative variables that can predict AKI and CKD may help guide shared decision making. Impact of postsurgical AKI was limited to less severe CKD (eGFR<60 ml/min 71.73m2). Confirmatory studies are requisite.

Diabetes, Obesity, and Pathological Upstaging in Renal Cell Carcinoma: Results From a Large Multi-institutional Consortium.

PURPOSE: We sought to determine whether clinical risk factors and morphometric features on preoperative imaging can be utilized to identify those patients with cT1 tumors who are at higher risk of upstaging (pT3a). MATERIALS AND METHODS: We performed a retrospective international case-control study of consecutive patients treated surgically with radical or partial nephrectomy for nonmetastatic renal cell carcinoma (cT1 N0) conducted between January 2010 and December 2018. Multivariable logistic regression models were used to study associations of preoperative risk factors on pT3a pathological upstaging among all patients, as well as subsets with those with preoperative tumors ≤4 cm, renal nephrometry scores, tumors ≤4 cm with nephrometry scores, and clear cell histology. We also examined association with pT3a subsets (renal vein, sinus fat, perinephric fat). RESULTS: Among the 4,092 partial nephrectomy and 2,056 radical nephrectomy patients, pathological upstaging occurred in 4.9% and 23.3%, respectively. Among each group independent factors associated with pT3a upstaging were increasing preoperative tumor size, increasing age, and the presence of diabetes. Specifically, among partial nephrectomy subjects diabetes (OR=1.65; 95% CI 1.17, 2.29), male sex (OR=1.62; 95% CI 1.14, 2.33), and increasing BMI (OR=1.03; 95% CI 1.00, 1.05 per 1 unit BMI) were statistically associated with upstaging. Subset analyses identified hilar tumors as more likely to be upstaged (partial nephrectomy OR=1.91; 95% CI 1.12, 3.16; radical nephrectomy OR=2.16; 95% CI 1.44, 3.25). CONCLUSIONS: Diabetes and higher BMI were associated with pathological upstaging, as were preoperative tumor size, increased age, and male sex. Similarly, hilar tumors were frequently upstaged.

Incidence and clinical relevance of paraneoplastic syndromes in patients with renal cell carcinoma.

BACKGROUND: Paraneoplastic syndromes (PNS) are defined as the signs and symptoms attributed to cytokines or hormones released from a tumor or a patient's immune system. PNS have been reported with many cancers for decades and data supporting their relevance in renal cell carcinoma (RCC) are largely historical. The widespread use of electronic medical record (EMR) systems provides a more robust method to capture data. The objective of this study was to establish contemporary data regarding the incidence and relevance of PNS in patients undergoing nephrectomy for suspected RCC. METHODS: In this retrospective single-institution study, 851 patients undergoing nephrectomy for suspected RCC between 2011 and 2018 were assessed for the presence or absence of PNS as defined by laboratory abnormalities. Factors associated with PNS and with all-cause mortality were examined. RESULTS: The incidence of PNS was 33.1% among 851 patients prior to nephrectomy. The most prevalent PNS were anemia (22.4%), thrombocytosis (7.5%), and elevated C-reactive protein (CRP) (7.4%). PNS were more common in women (39.2% vs. 29.4%, p = 0.0032) and higher stage RCC (31.1% of stage I vs. 54.2% of stage IV, p = 0.0036). Factors associated with the presence of PNS in multivariable analysis included female gender, high comorbidity, and stage IV RCC. Prenephrectomy PNS were associated with poorer survival in multivariable analysis (HR: 2.12, p = 0.0002). Resolution of PNS occurred in 52.1% of patients after nephrectomy, including 55.2% with stage I to III and 38.5% with stage IV RCC (p = 0.10). CONCLUSIONS: Using EMR data, laboratory evidence of PNS was present in one-third of a contemporary cohort of patients undergoing nephrectomy, with >50% of PNS resolving after surgery. Consistent with prior reports, PNS are more common in higher-stage RCC and are associated with poorer survival in RCC patients.

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.

Utilization of a Virtual Tumor Board for the Care of Patients With Renal Masses: Experience From a Quality Improvement Collaborative.

INTRODUCTION: Multidisciplinary tumor board meetings are useful sources of insight and collaboration when establishing treatment approaches for oncologic cases. However, such meetings can be time intensive and inconvenient. We implemented a virtual tumor board within the Michigan Urological Surgery Improvement Collaborative to discuss and improve the management of complicated renal masses. METHODS: Urologists were invited to discuss decision-making for renal masses through voluntary engagement. Communication was performed exclusively through email. Case details were collected and responses were tabulated. All participants were surveyed about their perceptions of the virtual tumor board. RESULTS: Fifty renal mass cases were reviewed in a virtual tumor board that included 53 urologists. Patients ranged from 20-90 years old and 94% had localized renal mass. The cases generated 355 messages, ranging from 2-16 (median 7) per case; 144 responses (40.6%) were sent via smartphone. All urologists (100%) who submitted to the virtual tumor board had their questions answered. The virtual tumor board provided suggestions to those with no stated treatment plan in 42% of cases, confirmed the physician's initial approach to their case in 36%, and offered alternative approaches in 16% of cases. Eighty-three percent of survey respondents felt the experience was "Beneficial" or "Very Beneficial," and 93% stated increased confidence in their case management. CONCLUSIONS: Michigan Urological Surgery Improvement Collaborative's initial experience with a virtual tumor board showed good engagement. The format reduced barriers to multi-institutional and multi-disciplinary discussions and improved the quality of care for selected patients with complex renal masses.

Guideline Compliance Regarding Chest Imaging of Suspicious cT1 Renal Masses in MUSIC-KIDNEY.

INTRODUCTION: Multiple urological societies recommend chest imaging for suspicious renal masses using chest x-ray or CT as clinically indicated. The purpose of chest imaging is to assess for thoracic metastasis at the time of renal mass diagnosis. Ideally, imaging use and type are commensurate with risk related to tumor size and clinical stage. We examined current practice patterns with chest imaging compliance in the state of Michigan and implemented clinician education and value-based reimbursement incentivization on guideline adherence. METHODS: MUSIC (Michigan Urological Surgery Improvement Collaborative)-KIDNEY (Kidney mass: Identifying and Defining Necessary Evaluation and therapY) is a statewide initiative focusing on quality improvement for patients with cT1 renal masses. Data regarding chest imaging in MUSIC and panel discussion occurred at an in-person MUSIC meeting in October 2019. Adherence to chest imaging guidelines was made a value-based reimbursement metric at the triannual MUSIC meeting in January 2020. Adherence was defined as optional in renal masses <3 cm (CT not indicated), recommended in renal masses 3-5 cm (chest x-ray preferred), and required in renal masses >5 cm (CT preferred). The MUSIC registry was queried for percentage of patients receiving chest imaging by type. Factors associated with adherence were assessed. RESULTS: There was significant practice-level variation in chest imaging rates across the 14 contributing practices, ranging from 11% to 68%. Compliance with MUSIC guidelines for chest imaging during evaluation of T1 renal masses was 81.8% overall, with only 61.8% of patients with masses >5 cm meeting the guideline requiring imaging with preference for CT. Factors associated with increased adherence included larger tumor size (T1b vs T1a) and solid (vs cystic or indeterminate) tumor (P < .05 for each). Prior to value-based reimbursement introduction, 46.7% of patients underwent imaging of either type, compared to 49.0% post-intervention. Imaging rates only slightly increased in masses >5 cm (58.3% before value-based reimbursement vs 61.2% after, P = .56) and 3-5 cm (50.0% before value-based reimbursement vs 56.2% after, P = .0585). CONCLUSIONS: Chest imaging guideline adherence during the initial evaluation of cT1 renal masses is acceptable, particularly given that most masses are <3 cm, for which metastatic risk is low. However, despite consensus from major urological societies regarding imaging for masses >4-5 cm, imaging rates were low across MUSIC. After educational and value-based reimbursement incentive initiation, rates of imaging for 3-5-cm and >5-cm masses changed only slightly. There remains significant practice variability and room for improvement.

Initial Management of Indeterminate Renal Lesions in a Statewide Collaborative: A MUSIC-KIDNEY Analysis.

PURPOSE: Renal masses can be characterized as "indeterminate" due to lack of differentiating imaging characteristics. Optimal management of indeterminate renal lesions remains nebulous and poorly defined. We assess management of indeterminate renal lesions within the MUSIC-KIDNEY (Michigan Urological Surgery Improvement Collaborative-Kidney mass: Identifying and Defining Necessary Evaluation and therapY) collaborative. MATERIALS AND METHODS: Each renal mass is classified as suspicious, benign, or indeterminate based on radiologist and urologist assessment. Objectives were to assess initial management of indeterminate renal lesions and the impact of additional imaging and biopsy on characterization prior to treatment. RESULTS: Of 2,109 patients, 444 (21.1%) had indeterminate renal lesions on their initial imaging, which included CT without contrast (36.2%), CT with contrast (54.1%), and MRI (9.7%). Eighty-nine patients (20.0%) underwent additional imaging within 90 days, 8.3% (37/444) underwent renal mass biopsy, and 3.6% (16/444) had reimaging and renal mass biopsy. Additional imaging reclassified 58.1% (61/105) of indeterminate renal lesions as suspicious and 21.0% (22/105) as benign, with only 20.9% (22/105) remaining indeterminate. Renal mass biopsy yielded a definitive diagnosis for 87%. Treatment was performed for 149 indeterminate renal lesions (33.6%), including 117 without reimaging and 123 without renal mass biopsy. At surgery for indeterminate renal lesions, benign pathology was more common in patients who did not have repeat imaging (9.9%) than in those who did (6.7%); for ≤4 cm indeterminate renal lesions, these rates were 11.8% and 4.3%. CONCLUSIONS: About 33% of patients diagnosed with an indeterminate renal lesion underwent immediate treatment without subsequent imaging or renal mass biopsy, with a 10% rate of nonmalignant pathology. This highlights a quality improvement opportunity for patients with cT1 renal masses: confirmation that the lesion is suspicious for renal cell carcinoma based on high-quality, multiphase, cross-sectional imaging and/or histopathological features prior to surgery, even if obtaining subsequent follow-up imaging and/or renal mass biopsy is necessary. When performed, these steps lead to reclassification in 79% and 87% of indeterminate renal lesions, respectively.