Surveillance Of Small Renal Masses Research Articles

The Role of Imaging in the Active Surveillance of Small Renal Masses

Up to 66 % of renal cell carcinomas are detected as small renal masses before the presence of clinical symptoms. Small renal mass treatment has evolved from the exclusive use of radical nephrectomy to the use of nephron sparing procedures where possible. An increase in elderly and comorbid patients, together with the notion that just 20 % of small renal masses show high malignant potential, has prompted interest in active surveillance as a treatment option. Modern imaging techniques provide objective follow-up parameters, namely size, invasion of collecting system or perirenal fat and enhancement patterns, with minimal complication risks or patient discomfort. This review evaluates recent developments in the field of active surveillance for small renal masses. Special focus is placed on the role of imaging in the primary decision making and subsequent follow-up during active surveillance.

Active surveillance for small renal masses diagnosed in elderly or comorbid patients: Looking for the best treatment strategy

IntroductionAim of this study is to provide our results after long-term active surveillance (AS) protocol for small renal masses (SRMs), and to report the outcomes of patients who remained in AS compared to those who underwent delayed surgical intervention. Patients and methodsWe retrospectively reviewed our database of 58 patients diagnosed with 60 contrast enhancing SRMs suspicious for renal cell carcinoma (RCC). All patients had clinical and radiological follow-up every 6 months. We evaluated the differences between patients who remained on AS and those who underwent surgical delayed intervention. ResultsThe mean age was 75 years, the mean follow-up was 88.5 months. The median initial tumor size at presentation was 2.6cm, and the median estimated tumor volume was 8.7cm3. The median linear growth rate of the cohort was 0.7cm/year, and the median volumetric growth rate was 8.8cm3/year. Death for metastatic disease occurred in 2 patients (3.4%). No correlation was found between initial tumor size and size growth rate. The mean linear and volumetric growth rates of the group of patients who underwent surgery were higher than in those who remained on surveillance (1.9 vs. 0.4cm/year and 16.1 vs. 4.6 cm3/year, respectively; p<.001). ConclusionsMost of SRMs demonstrate to have an indolent course and low metastatic potential. Malignant disease could have faster linear and volumetric growth rates, thus suggesting the need for a delayed surgical intervention. In properly selected patients with low life-expectancy, AS could be a reasonable option in the management of SRMs.

Surgery versus surveillance of small renal masses: a call for comparative effectiveness research in the management of kidney tumors

Surgery versus surveillance of small renal masses: a call for comparative effectiveness research in the management of kidney tumors

Active surveillance of small renal masses

The increased diagnosis of small renal masses (SRMs) poses the challenge of how best to manage patients with tumours that are not likely to progress and cause death during their lifetime. Concerns regarding overdiagnosis and overtreatment of patients with low-risk or indolent disease has led to the introduction of active surveillance as an alternative to immediate intervention in select candidates. However, differentiating between benign or low-grade lesions and high-grade aggressive phenotypes is difficult. Renal biopsy, radiographic assessment, and clinical nomograms have been used before surgery to evaluate the probability of whether an SRM will exhibit characteristics of an aggressive cancer. SRM growth trends have been studied over periods of observation but no characteristics have been found to correlate with aggressive growth kinetics. Stratification of patients with SRMs according to risk status is crucial when considering whether active surveillance might be an appropriate treatment option. Factors that should be taken into account include comorbidities, a history of malignancy, pre-existing chronic kidney disease, life expectancy and patient preference. Standardized active surveillance protocols are currently lacking, and clinical trials designed to randomize patients with SRMs to receive either active surveillance or immediate treatment are sorely needed to address the existing evidence gap.

IJU this issue

This issue contains two Review Articles, nine Original Articles, two Procedures, one Case Report and four Letters to the Editor. The two Reviews describe the topics of kidney cancer and prostate cancer. Gontero et al. (Turin, Italy) discussed active surveillance for small renal masses. They concluded that active surveillance is feasible and safe in elderly and comorbid patients. Regarding prostate cancer, Ahmed and Li (San Francisco, USA) reviewed current perspectives regarding key questions about two models, “adaptation” and “clonal selection”, in the course of progression to castration-resistant prostate cancer. In the Original Articles, five articles are about urological cancer, and four articles are about urinary continence and voiding functions. In relation to low-stage renal cell carcinoma, Sun et al. (Montreal, Canada) reported worse cancer-specific mortality in patients with nodal metastasis at nephrectomy. Sejima et al. (Yonago, Japan) analyzed the outcomes after radical nephrectomy for renal cell carcinoma. They concluded that post-radical nephrectomy renal function insufficiency can lead to a poor prognostic outcome, especially in patients with T1 tumors. For patients with muscle-invasive bladder cancer undergoing radical cystectomy, Simone et al. (Rome, Italy) evaluated the impact of an extended versus a standard pelvic lymph node dissection. They supported an extended pelvic lymph node dissection as the optimal staging and therapeutic procedure. In the management of non-muscle invasive bladder cancer, Del Rosso et al. (L'Aquila, Italy) described depending on their single center randomized controlled trial that bipolar transurethral resection showed a safe and effective procedure. In an Editorial Comment on this paper, Naselli (Castellanza, Italy) said that their data are insufficient to support bipolar transurethral resection of bladder tumor as a new standard. On prostate cancer, Abdollah et al. (Montreal, Canada) discussed and concluded that none of the guidelines can be regarded as an ideal indication for pelvic lymph node dissection for prostate cancer. For this article, two interesting opinions appear in this issue as Editorial Comments. Gandaglia et al. (Milan, Italy) investigated the effect of phosphodiesterase type 5 inhibitor (PDE5-I) on urinary continence (UC) recovery after bilateral nerve-sparing radical prostatectomy. They reported that the use of PDE5-I significantly improved UC recovery after surgery. However, regarding this article, Gacci (Florence, Italy) mentioned, as an Editorial Comment, that further prospective randomized controlled trials with long-term follow up are necessary. About voiding function of benign prostatic hyperplasia (BPH) patients, Masumori et al. (Sapporo, Japan) showed the 5-year outcome analysis of the α1-blocker, tamsulosin, as an initial treatment for patients with BPH. And they concluded that α1-blocker monotherapy might not be appropriate for achieving a good long-term outcome in patients with a large prostate volume and a large amount of residual urine. As for insensible urinary incontinence, Brucker et al. (New York, USA) reported a study to define urodynamic findings. They showed characteristic urodynamic findings and an association of incontinence with other symptoms. Moore et al. (Atlanta, USA) showed 2-year evaluation data of the MiniArc sling for treatment of stress urinary incontinence, and concluded that the procedure represents a safe and effective treatment option for both obese and non-obese patients. As Procedures, two interesting techniques are shown regarding laparoscopic surgery. Zarrelli et al. (Borgosesia, Italy) presented the knotless “three-U-stitches” technique for urethrovesical anastomosis in laparoscopic radical nephrectomy. Tsuji et al. (Nagoya, Japan) showed the identification method of the narrow lumen of the ureter using a Fogarty catheter during laparoscopic pyeloplasty. In the one Case Report in this issue, Suzuki et al. (Yamanashi, Japan) reported an interesting case of the first male patient reported in the literature with malignant mixed epithelial and stromal tumor of the kidney. As for the four Letters to the Editor, every opinion is interesting. None declared.

1067 DELAYED INTERVENTION AND SURVEILLANCE FOR SMALL RENAL MASSES: UPDATE FROM A PROSPECTIVE REGISTRY OF ACTIVE SURVEILLANCE

INTRODUCTION AND OBJECTIVES: A growing body of retrospective literature has emerged regarding active surveillance (AS) for select patients with small renal masses 4.0 cm (SRM). Herein we present interim results of the prospective ‘Delayed Intervention and Surveillance for Small Renal Masses (DISSRM) Registry’ comparing active surveillance and intervention for small renal masses (SRMs). METHODS: Patients were prospectively enrolled into the multiinstitutional IRB approved DISSRM registry study following consultation and choice of AS or intervention. A scoring system (DISSRM score) for suitability of AS was developed based on existing literature and early experience with this registry and includes added points for higher age, ECOG performance status, Charlson Comorbidity Index (CCI), chronic kidney disease (CKD), and smaller tumor size ( 3cm). DISSRM score was calculated for all patients and compared between AS and intervention patients. Disease specific (DSS) and overall survival (OS) data is presented along with growth kinetics of tumors on AS and analysis of cross-over from AS to intervention. RESULTS: At 46 months, 327 patients have enrolled: 226 (69.1%) elected immediate intervention and 101 (30.9%) elected AS; among the latter 16 (4.9%) crossed-over to delayed intervention. Patients undergoing AS were older, had a higher ECOG performance status, worse Charlson Comorbidity Index scores, more hematuria and smaller tumors. DISSRM Score was significantly different between patients undergoing intervention and AS (p 0.015): 84% of patients undergoing intervention had a DISSRM Score 4, 45% of patients undergoing AS had a score 3. At a median follow-up of 18 months (6-42 months), four patients undergoing AS have died (none related to RCC) and none have developed metastases. Average growth rate for patients with 6 months follow-up is 0.10 cm/year ( 2.23 to 2.24). Four patients undergoing immediate intervention have died; one patient undergoing intervention died of RCC recurrence. CONCLUSIONS: This study represents one of the largest prospectively assembled disease registries for patients with a small renal mass. Over 65% of patients with SRM select immediate intervention versus AS in a multi-institutional registry. Progression-free survival and CSS are excellent with intermediate follow-up. The DISSRM Score helps to differentiate patients suitable for AS from those suitable for immediate intervention.

633 QUALITY OF LIFE ON ACTIVE SURVEILLANCE FOR A SMALL RENAL MASSES VERSUS IMMEDIATE INTERVENTION: INTERIM ANALYSIS OF THE DISSRM (DELAYED INTERVENTION AND SURVEILLANCE FOR SMALL RENAL MASSES) REGISTRY

INTRODUCTION AND OBJECTIVES: Quality-of-life (QOL) measures have not been evaluated in a rigorous fashion for patients undergoing active surveillance (AS) for small renal masses (SRM). The prospective, multi-institutional Delayed Intervention and Surveillance for Small Renal Masses (DISSRM) Registry was opened January 1, 2009, enrolling patients with SRM 4.0 cm who chose intervention or AS. METHODS: Patients were enrolled following consultation and choice of AS or intervention. Those electing AS followed an imaging protocol every 4-6 months for 2 years, then 6 months for 3 years. SF12 QOL questionnaires were completed at enrollment, at 6 and 12 months, and annually thereafter. Mental Component Summary (MCS), Physical Component Summary (PCS) and overall score were evaluated among groups and over time with analysis of variance. RESULTS: At 46 months, 327 patients have enrolled: 226 (69.1%) elected immediate intervention and 101 (30.9%) elected AS. At a median follow-up of 18 months (6-42 months), 782 questionnaires have been completed. QOL Scores are shown in the Table. At baseline there was a significant difference in total score (p 0.008) among groups. There was not a significant trend in change of total score over time in either group. Compared with AS, PCS scores were significantly higher for immediate intervention at baseline (p 0.0001), 6 months (p 0.0002) and 1 year (p 0.0446). There was no difference in MCS among groups at any time point. CONCLUSIONS: In a large, multi-institutional, prospective registry of patients undergoing AS or immediate intervention for SRM, patients undergoing immediate intervention have higher QOL scores at baseline specifically in domains that reflect their physical health. The perceived benefit in physical health persists for at least one year following intervention. Mental health, which includes domains of depression and anxiety, is not adversely affected while on AS.

1183 SURVEILLANCE FOR THE MANAGEMENT OF SMALL RENAL MASSES: OUTCOMES IN A POPULATION-BASED COHORT

INTRODUCTION AND OBJECTIVES: Small renal masses (SRM) are a heterogeneous group of tumors with varying malignant potential. Although surgery is the standard treatment for SRM, emerging evidence suggests that surgical intervention, particularly in elderly or morbidly ill patients, may be unnecessary and may adversely affect non-oncologic outcomes. Our objective was to examine the impact of surveillance of SRM on morbidity and mortality compared with surgical treatment. METHODS: From Surveillance, Epidemiology, and End Results (SEER) cancer registry data linked with Medicare claims, we performed a retrospective cohort study of patients age 66 years or older who were managed with surveillance or surgery for a pathologically confirmed kidney cancer 4 cm diagnosed in 2000-2007. Surveillance was defined by the absence of Medicare claims for surgery or other treatment in the first 6 months following diagnosis. Primary endpoints were death from any cause, death due to renal cancer and cardiovascular (CV) events. Propensity score methods were used to control for potential confounders in multi-variable analysis. RESULTS: Of 7,148 patients, 1,584 (22%) were managed with surveillance and 5,564 (78%) had surgery including 3,623 (65%) who had radical nephrectomy (RN) and 1,941 (35%) who had nephron sparing surgery (NSS). During a median follow-up of 59 months, 1,689 patients (24%) had at least one CV event and 1,536 patients (21%) died, including 191 (3%) who died of kidney cancer. Cancer-specific survival did not differ by treatment approach (HR 0.67; CI 0.44-1.04). Controlling for patient and disease characteristics, surveillance was associated with a significantly lower risk of death from any cause (hazard ratio [HR] 0.63; CI 0.54-0.74) and of suffering a CV event (HR 0.51; CI 0.44-0.60). Compared with surveillance, the risk of death from any cause was greatest among those treated with RN (HR 1.75; CI 1.49-2.05) but was also elevated among those who had PN (HR 1.34; CI 1.12-1.61). CONCLUSIONS: For older patients with SRM, surveillance does not appear to adversely affect cancer specific survival, while surgery, particularly RN may be associated with increased risk CV complications and death from any cause. Surveillance should be considered an option for patients with SRM, who are not otherwise acceptable candidates for surgery. Source of Funding: None

179 Nephrectomy versus active surveillance for small renal masses: Cancer-specific mortality and competing-risks of death

179 Nephrectomy versus active surveillance for small renal masses: Cancer-specific mortality and competing-risks of death

174 Active surveillance of small renal masses: First Italian prospective study

174 Active surveillance of small renal masses: First Italian prospective study

Extensive renal infarction following percutaneous biopsy of a small renal mass: A case report

Percutaneous renal biopsy has become increasingly used particularly in patients undergoing active surveillance for small renal masses. We present a patient, who was recently diagnosed with laryngeal squamous cell carcinoma, with significant complication following biopsy of a solid renal mass. The patient was planned for nephron-sparing surgery that was converted to radical nephrectomy due to extensive renal infarction secondary to significant subcapsular hemorrhage inflicted by the biopsy.

Surveillance for the management of small renal masses: Utilization and outcomes in a population-based cohort.

343 Background: Small renal masses (SRM) are comprised of a heterogeneous group of tumors with some having malignant potential. Although surgery is the standard treatment for SRMs, emerging data suggests that surgery in the elderly or morbidly ill patients may be unnecessary and may adversely impact non-oncologic outcomes. We analyzed a population-based cohort of patients to identify predictors of surveillance and assess the impact of surveillance on overall survival, kidney cancer-specific survival and cardiovascular (CV) events, compared with surgery. Methods: From surveillance, epidemiology, and end results (SEER) cancer registry data linked with Medicare claims, we performed a retrospective cohort study of patients 66 years of age or older who received surgery or surveillance for SRM (&lt; 4 cm) diagnosed between 2000 to 2007. Propensity score methods were used to control for potential confounders in multivariable analysis. Results: Of 8,317 patients, 5,706 (70%) underwent surgery and 2,611 (31%) underwent surveillance. The use of surveillance increased from 25% in 2000 to 37% in 2007 (p &lt; 0.001). During a median follow-up of 58 months, 2,053 (25%) patients had at least one CV event and 2,078 (25%) patients died, including 277 (3%) who died of kidney cancer. Compared with surgery, surveillance was associated with a significantly lower risk of death from any cause (hazard ratio [HR], 0.84; CI, 0.75-0.94) and of suffering a CV event (HR, 0.79; CI 0.70-0.89), controlling for patient and disease characteristics. Kidney cancer-specific survival did not differ by treatment approach (HR, 0.89; CI, 0.66-1.21). Conclusions: There is increasing utilization of surveillance as an initial treatment strategy for patients with SRMs. For older patients with SRM, surveillance does not appear to adversely affect kidney cancer-specific survival, while surgery may be associated with CV complications and an increased risk of death from any cause. Surveillance should be considered an option for patients with SRM who are not otherwise acceptable candidates for surgical treatment.

Surveillance for small renal masses: retrospective analysis of a cohort of 42 patients with long-term follow-up

To provide our experience with active surveillance in patients incidentally diagnosed with small renal masses and show the results of long-term follow-up. We retrospectively evaluated a cohort of 42 patients diagnosed with small renal mass (≤ 4 cm in diameter). All patients had clinical and radiological follow-up every 6 months. We evaluated the differences between patients who remained on surveillance and those who underwent surgical delayed intervention and the correlations between clinical variables and size growth rate. The mean patients' age was 75 years (66-90); the mean follow-up was 69.4 months (range 35-168). The median initial tumor size at presentation was 2.5 cm (range 1-4.3), and the median estimated tumor volume was 8.6 cm(3) (range 1.7-42.3). The median growth rate of the cohort was 0.8 cm/year (range 0.2-2.9), and the median volumetric growth rate was 9.1 cm(3)/year (range 0-19.6). Death for metastatic disease occurred in 2 patients died due to metastatic disease (4.7 %). No correlation was found between initial tumor size and size growth rate. The mean growth rate of the group of patients who underwent surgery was higher than in those who remained on surveillance (1.8 vs. 0.4 cm/year; P < 0.001). The most of small renal masses initially managed by surveillance will grow slowly and will have a low metastatic potential. Tumor size at diagnosis is not able to predict the natural history of renal masses, even if malignant disease may have a higher growth rate. In elderly patients with relevant co-morbidities, surveillance can be a reasonable option alternative to surgery.

Active surveillance for small renal tumors: Have clinical concerns been addressed so far?

The incidence of small renal masses is increasing, as a result of the wide adoption of imaging exams. Their management, however, is complicated, especially in patients with decreased life expectancy or comorbidities. Approximately 20% of small renal masses are benign and, even if malignant, just 10% show aggressive pathological features. Furthermore, competing cause mortality seems to exceed the cancer-specific mortality in patients aged over 70 years. The role of percutaneous tumor biopsy is still not well defined. All these observations raise the concern as to whether surgery might represent an overtreatment for some cases of small renal masses, calling into question the role of active surveillance. The aim of this review was to evaluate the current evidence pertaining to several hot questions that need to be addressed when contemplating active surveillance for small renal masses. The most relevant publications on this subject available in the literature were selected. Five representative series of active surveillance along with the main related variables were identified. Some relevant items surrounding the field of active surveillance were identified and submitted to an evidence-based discussion. According to the recent evidence, small renal masses under active surveillance tend to show an indolent course with a low probability of disease progression, the latter being triggered most of the time by a tendency to grow faster. Unfortunately, we are currently unable to predict those few cases with aggressive behavior. According to the current evidence, active surveillance is feasible and safe in elderly and comorbid patients.

Growth kinetics and active surveillance for small renal masses

Management options for small renal masses (SRMs) include excision, ablation, and active surveillance. Increasing interest in active surveillance, particularly for tumors of limited oncologic potential, in patients with other significant health concerns continues to rise, but precise protocols are still lacking. A review of 18 retrospective series of patients undergoing active surveillance for 957 SRMs indicates that the majority grew during observation (mean 0.32 cm/year), but only 1.4% metastasized during 32 months of follow-up (median). One published prospective series of 209 SRMs reported average growth of 0.13 cm/year and only 1% metastasized. Maximal tumor diameter (or volume) at presentation is a predictor of growth rate, high-grade disease, and likelihood of metastasis. SRMs less than 3 cm are very unlikely to metastasize and deferring treatment has not been associated with increased failure to cure. Active surveillance is a reasonable initial strategy in most patients with SRMs, particularly those with limited life-expectancy and increased perioperative risk. Intervention should be considered for growth to greater than 3-4 cm or by greater than 0.4-0.5 cm/year while on active surveillance.

Active surveillance of small renal masses offers short‐term oncological efficacy equivalent to radical and partial nephrectomy

Study Type - Therapy (case series) Level of Evidence 4. What's known on the subject? and What does the study add? Active surveillance of small renal masses has traditionally been reserved for elderly patients deemed unfit for surgery or ablation. There is increasing evidence showing the safety of active surveillance in the management of small renal masses. In this retrospective study we compared outcomes for patients with small renal masses managed with active surveillance, radical nephrectomy and partial nephrectomy. We showed that active surveillance was safe and appeared as effective as immediate surgery in the management of small renal tumours. • To compare the oncological outcomes of active surveillance (AS), radical nephrectomy (RN) and partial nephrectomy (PN) in the management of T1a small renal masses (SRMs). • At present AS is used in the treatment of SRMs in elderly patients with multiple co-morbidities or in those who decline surgery. • We identified all patients with T1a SRMs managed with RN, PN or AS. • Retrospective data were collected from patient case records with survival data and cause of death cross-referenced with the Oxford Cancer Intelligence Unit. • A total of 202 patients with 234 T1a SRMs (solid or Bosniak IV) were identified; 71 patients were managed with AS, 41 with an RN and 90 by PN. • Over a median follow-up of 34 months the mean growth rate on AS was 0.21 cm/year with 53% of SRMs managed with AS showing negative or zero growth. • No statistically significant difference was observed in overall (OS) and cancer-specific (CSS) survival for AS, RN and PN (AS-CSS 98.6%, AS-OS 83%; RN-CSS 92.6%, RN-OS 80.4%; PN-CSS 96.6%, PN-OS 90.0%). • Active surveillance of SRMs offers oncological efficacy equivalent to surgery in the short/intermediate term. • The results of this study support a multicentre prospective randomized controlled trial designed to compare the oncological efficacy of AS and surgery.

Abstract 1278: Determining the proteomic changes that define progressor and non-progressor clear cell renal cell carcinoma

Abstract Renal cell carcinoma (RCC) is the most common type of kidney cancer, is increasing in incidence and is the most lethal genitourinary cancer. Due to the increased use of abdominal imaging, small renal masses (SRMs), mostly RCC, are now commonly detected in asymptomatic individuals and are the most common presentation of kidney cancer. Many of these SRMs grow slowly or not at all, while about 30% progress to advanced stages. However, in the absence of factors distinguishing masses that need treatment from those that can be managed by surveillance alone, most SRMs are treated by surgery. Clear cell RCC (ccRCC) is the most common form of RCC, has the worst prognosis and is characterized by inactivation of von Hippel-Lindau tumor suppressor gene (VHL). Systemic therapies developed to treat patients at advanced stages have targeted pVHL regulated genes particularly hypoxia inducible factor (HIF) downstream targets. However, these drugs rarely achieve cures suggesting that other pathways are implicated in ccRCC initiation and progression. Our national clinical trial, “Active Surveillance of Small Renal Masses” provides a unique opportunity to study the genetics and biology of the early stage ccRCC and characterize the genomic and proteomic signatures distinguishing non-progressor from progressor ccRCC-SRMs. Patients with ccRCC-SRMs (&amp;lt;4cm in size) are followed with time and if their mass progresses, they undergo surgical or other forms of intervention as appropriate. In this study, we determine the proteomic differences between a) non-progressor and progressor ccRCC-SRMs by characterizing biopsies taken at the time of diagnosis and recruitment into the surveillance protocol from both groups, and b) progressor ccRCC-SRM (at time of recruitment) and advanced ccRCC by comparing the initial, diagnostic biopsy of ccRCC-SRMs that subsequently progress to the surgical specimen at the time of treatment for progression (advanced stage). Using reverse phase protein array (RPPA), we identify proteomic signatures that distinguish progressor and non-progressor groups. We observed changes mostly in the PI3 kinase and ERK pathways as well as alterations in apoptotic pathways. Our results provide important insight for management of ccRCC-SRMs and define pathways involved in their initiation and progression. This could furthermore identify potential therapeutic targets that would lead to better management of ccRCC patients. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 1278. doi:1538-7445.AM2012-1278

1118 Active surveillance of small renal masses offers short-term oncologic efficacy equivalent to radical and partial nephrectomy

1118 Active surveillance of small renal masses offers short-term oncologic efficacy equivalent to radical and partial nephrectomy

A Multidisciplinary Evaluation of Inter-Reviewer Agreement of the Nephrometry Score and the Prediction of Long-Term Outcomes

The nephrometry score was introduced in 2009 as a way to quantify renal tumor complexity in a systematic way. However, the reproducibility of scoring has not been rigorously validated across specialty or level of training, nor has it been evaluated with regard to meaningful clinical outcomes. We identified 95 consecutive patients with a solid renal mass treated surgically. Each renal tumor was separately scored by 6 reviewers, including 2 staff urologists, 1 staff radiologist, 2 trainees (1 urology, 1 radiology) and 1 medical student. Inter-reviewer agreement for nephrometry score was evaluated using Lin's concordance correlation coefficient. We evaluated the ability of the nephrometry score to predict surgery type, pathological features and clinical outcomes. Agreement in nephrometry score was substantial among the 3 staff physicians (0.72, 95% CI 0.64-0.80). Nephrometry score agreement continued to be substantial when including the trainees and medical student in the analysis (0.75, 95% CI 0.69-0.81). The median nephrometry score of patients treated with radical nephrectomy was 9.0 vs 7.2 for those treated with a nephron sparing approach (p <0.001). Increasing nephrometry score was associated with increased risk of distant metastasis (HR 3.27, p <0.001), death from renal cell carcinoma (HR 2.83, p <0.001) and death from any cause (HR 1.24, p = 0.017). Nephrometry scoring with minimal initial instruction was robust across specialties and levels of training. The additional anatomical information that nephrometry score adds to size alone may be associated with other important clinical outcomes such as tumor aggressiveness and survival, and warrants further study.

Most Renal Oncocytomas Appear to Grow: Observations of Tumor Kinetics With Active Surveillance

We examined the growth of tissue proven renal oncocytoma on serial imaging to improve our understanding of its natural history. We reviewed the charts of 69 patients with oncocytoma diagnosed by biopsy or surgery between 2004 and 2010. A total of 29 cases were managed by active surveillance for at least 12 months and had 3 or more imaging events. Tumor size was documented and the average tumor growth rate was calculated using a random coefficient model. Interaction terms were used to investigate correlations between variables of interest, including age at diagnosis, gender, symptom status, laterality, initial tumor size, surveillance duration and number of imaging events. At a mean surveillance duration of 40 months 80% of oncocytomas increased in size. Based on the random coefficient model the estimated average growth rate was 0.16 mm monthly (95% CI 0.097-0.228, p <0.0001). We identified no variables that significantly correlated with growth. Despite its low metastatic potential renal oncocytoma appears to progress locally with a growth rate similar to that of RCC. Thus, absent tumor growth on serial imaging is not a robust prognostic factor for benign histology. Biopsy remains the mainstay of diagnosis. At centers where it can be performed safely and accurately, active surveillance of tissue proven oncocytoma appears to be safe in the short term. Alternative management includes partial nephrectomy and minimally invasive approaches. To our knowledge this is the largest study of oncocytoma natural history.