Effect of renal cancer size on the prevalence of metastasis at diagnosis and mortality

Radiological Features of T1a Renal Cell Carcinoma on Axial Unenhanced Computed Tomography

CT has become a commonly used diagnostic procedure in clinical practice, particularly in emergency healthcare delivery. Accordingly, the increase in CT usage has increased the likelihood of incidental detections (ID) of renal cell carcinomas (RCCs). This article discusses key points and limitations associated with the diagnosis and characterization of T1a RCC (≤4 cm in diameter) and shows how to improvise on the differentiation of T1a RCC with unenhanced CT (UE-CT). We retrospectively reviewed UE-CT findings of cases associated with the histopathologic diagnosis of T1a RCC and examined the discrimination capacity and radiological characteristics with regard to small RCCs (SRCCs). Detection and characterization of T1a RCC based on UE-CT are not easy in many cases due to limitations in CT findings, but there are notable radiological features to facilitate detection and differentiation. The growth pattern is important for the detection of SRCCs. Internal characteristic features (average attenuation, heterogeneity) are useful for the characterization of the RCC. In addition, CT image visualization techniques may help improve the detectability of RCCs on UE-CT. Radiological features are important in detecting SRCCs and facilitating further examination. In this study, we discuss some cases of T1a RCCs and evaluate the radiological characteristics of the tumors seen on UE-CT.

Survival Improvement in Patients with Renal Cell Carcinoma and Disparities between Different Sexes, Races, and Socioeconomic Status: 1977–2016

Objective

Rare research of renal cell carcinoma (RCC) has been made in a comprehensive and full description based on a long period of time as yet. This study was aimed at investigating the incidence and relative survival rates (RSRs) of RCC in the past forty years and to disclose the impact of sex, race, and socioeconomic status (SES) on RCC.

Methods

The data as variables, including age, gender, race, and SES, were obtained from the Surveillance, Epidemiology, and End Results (SEER) database. SES was divided into three levels: low poverty, medium poverty, and high poverty. The medium- and high-poverty groups were integrated into one group in all analyses. The RSRs were calculated using period analysis methodology. Summary statistics including incidence and RSRs were analyzed by Kaplan–Meier and Cox proportional hazards models with GraphPad Prism 8.0.1 software and Stata 12.0 software.

Results

A total of 77,513 patients diagnosed with RCC were enrolled in this study, showing an increased incidence and 10-year RSRs from 1977 to 2016. Patients older than 60 years had the highest incidence and the lowest RSRs. This research also showed significant disparities between different groups: incidence in males, blacks, and medium-high poverty groups was higher than that in females, whites, and low poverty groups, while RSRs were lower. For sex groups, the disparity of RSRs was obvious among patients who were 30–59 years old, but not among those younger than 29 years or older than 60 years. Based on SES, the survival gaps between different SES groups were getting wider over the past forty years.

Conclusion

This study showed how age, sex, race, and SES affected the incidence and RSRs of RCC, which may be beneficial for both better designed clinical trials and efficient prevention methods.

Small renal mass with large lymph nodal metastasis and inferior vena cava thrombus: an exceptional amalgamation

A small renal mass is defined as a tumour <4cm. The standard treatment of choice for small renal masses is partial or radical nephrectomy, depending on the tumour anatomy, and has good overall and cancer-specific survival. Its association with lymph node metastasis and inferior vena cava (IVC) thrombus is very uncommon. We describe a case of a right small renal mass with a large metastatic paracaval lymph node with IVC level I thrombus who was treated with right radical nephrectomy with thrombus removal and lymph node excision.

Overview of clinical management for older patients with renal cell carcinoma

The rapidly increasing pool of older patients being diagnosed with and surviving their cancer is creating many challenges. Regarding localized renal cell carcinoma, surgery is considered as gold standard treatment options even in older men, whereas active surveillance and ablation therapy are alternative options for a proportion of these patients. With regard to advanced disease, anti-vascular endothelial growth factor tyrosine kinase inhibitors (VEGFR-TKI) and immune check point inhibitor are standard treatment modalities, although treatment choice from multiple regimens and prevention of adverse events need to be considered. Better assessment techniques, such as comprehensive geriatric assessment to meet the unique needs of older patients, are a central focus in the delivery of high-quality geriatric oncology care. Through this process, shared decision-making should be adopted in clinical care to achieve optimal goals of care that reflect patient and caregiver hopes, needs and preferences. It is necessary to continue investigating oncological outcomes and complications associated with treatment in this population to ensure appropriate cancer care. In this narrative review, we completed a literature review of the various treatments for renal cell carcinoma in older patients that aimed to identify the current evidence related to the full range of the treatments including active surveillance, surgery, ablation therapy and systemic therapy. Prospectively designed studies and studies regarding geriatric assessment were preferentially added as references. Our goals were to summarize the real-world evidence and provide a decision framework that guides better cancer practices for older patients with renal cell carcinoma.

Robustness and performance of radiomic features in diagnosing cystic renal masses

PURPOSE

We study the inter-reader variability in manual delineation of cystic renal masses (CRMs) presented in computerized tomography (CT) images and its effect on the classification performance of a machine learning algorithm in distinguishing benign from potentially malignant CRMs. In addition, we assessed whether the inclusion of higher-order robust radiomic features improves the classification performance over the use of first-order features.

METHODS

230 CRMs were independently delineated by two radiologists. Through a combination of random fluctuations, dilation, and erosion operations over the original region of interests (ROIs), we generated four additional sets of synthetic ROIs to capture the inter-reader variability realistically, as confirmed by dice coefficient measurements and visual assessment. We then identified the robust features based on the intra-class coefficient (ICC > 0.85) across these datasets. We applied a tenfold stratified cross-validation (CV) to train and test the performance of the random forest model for the classification of CRMs into benign and potentially malignant.

RESULTS

The mean area under the curve (AUC), sensitivity, specificity, positive predictive value, and negative predictive value were 0.87, 0.82, 0.90, 0.85, and 0.93, respectively. With the usage of first-order features alone, the corresponding values were nearly identical.

CONCLUSION

AUC ranged for the robust and uncorrelated features from 0.83 ± 0.09 to 0.93 ± 0.04 and for the first-order features from 0.84 ± 0.09 to 0.91 ± 0.04. Our study indicates that the first-order features alone are sufficient for the classification of CRMs, and that inclusion of higher-order features does not necessarily improve performance.

Renal Tumor Size and Presence Of Synchronous Lung Metastasis At Time Of Diagnosis: Implications For Chest Imaging

OBJECTIVE

To quantify synchronous lung metastasis risk based on renal tumor size and determine a renal tumor size threshold to determine when chest imaging is warranted.

METHODS

We assessed 253,838 patients diagnosed with a renal tumor who underwent staging chest imaging between 2010-2016 within the National Cancer Database. Patients were stratified by renal tumor size in 10 mm increments, and synchronous lung metastasis risk was calculated for each category. Logistic regression analyses were used to test the relationship between renal tumor size and presence of synchronous lung metastasis after adjusting to all available covariables.

RESULTS

Overall, 14,524 out of 253,838 (5.7%) patients had evidence of synchronous lung metastasis. Median (IQR) tumor size for patients with versus without sLM was 90 mm (65 - 115) vs. 40 mm (25 - 60), respectively. The incidence of synchronous lung metastasis was low for renal tumors <40 mm, without significant change, based on tumor size. Conversely, synchronous lung metastasis increased proportionally to renal tumor size for lesions ≥40 mm. In our cohort, 47% of patients (120,386/253,838) had a renal tumor <40 mm, and 0.9% (1,135/120,386) of these had patients had synchronous lung metastasis. Only 8% (1,135/14,524) of patients with synchronous lung metastasis had a renal tumor <40 mm.

CONCLUSION

The risk of synchronous lung metastasis increased proportionally to renal tumor size; however, the risk was low for tumors <40 mm. These findings suggest that there may be minimal utility of performing screening chest imaging for patients with renal tumors <40 mm.

Clinicopathologic Features of Small Renal Masses Associated With Distant Metastatic Disease

OBJECTIVES

To assess the clinicopathologic features of small renal masses (≤4 cm) associated with distant metastatic disease.

METHODS

We identified radical or partial nephrectomies with renal cell carcinomas (RCCs) measuring 4 cm or less in size (pT1a or pT3a) from 2005 to 2015. Clinicopathologic features were compiled.

RESULTS

A total of 590 RCCs 4 cm or less were identified, of which 3.9% were associated with distant metastatic RCC. Metastasis was more common in pT3a tumors 4 cm or less than pT1a tumors (19% vs 2.7%; P < .01). Seventy percent of tumors were clear cell RCCs. Overall, 43% of patients had previously (30%) or subsequently (13%) diagnosed RCC prior to development of metastasis, 80% of which were the same histologic subtype as the small renal mass.

CONCLUSIONS

Distant metastatic disease was rarely encountered in patients with small renal masses. Many of the patients with distant metastases had previously or subsequently diagnosed RCC, which could represent the true source of metastatic disease.

Small Renal Mass with Sarcomatoid Features

Interest in surveillance for small renal masses has expanded exponentially due to incidental detection with increased imaging. However, some of these small renal masses behave aggressively. Sarcomatoid pathology is associated with a worse prognosis. Traditionally, it has been thought of as a common pathway of dedifferentiation once a renal malignancy of any histology reaches a threshold size of approximately 3 cm. We report a case of a 65-year-old male with a 2 cm sarcomatoid renal cell carcinoma. To our knowledge, this is the smallest tumor with sarcomatoid differentiation reported in the literature.

Renal cell cancer treatment: an expert panel recommendation from the Latin American cooperative group-genitourinary and the Latin American renal cancer group: focus on surgery

Background:

Renal cell cancer (RCC) is one of the 10 most common cancers in the world, and its incidence is increasing, whereas mortality is declining only in developed countries. Therefore, two collaborative groups, The Latin American Oncology Cooperative Group-Genitourinary Section (LACOG-GU) and the Latin American Renal Cancer Group (LARCG), held a consensus meeting to develop this guideline.

Methods:

Issues (134) related to the treatment of RCC were previously formulated by a panel of experts. The voting panel comprised 26 specialists (urologists and medical oncologists) from the LACOG-GU/LARCG. A consensus was reached if 75% agreement was achieved. If there was less concordance, a new discussion was undertaken, and a consensus was determined by the most votes after a second voting session.

Results:

The expert meeting provided recommendations that were in line with the global literature; 75.0% of the recommendations made by the panel of experts were evidence-based level A, 22.5% of the recommendations were level B, and 2.5% of the recommendations were level D.

Conclusions:

This review suggests recommendations for the surgical treatment of RCC according to the LACOG-GU/LARCG experts.

Preoperative tumor size is associated with deep myometrial invasion and lymph node metastases and is a negative prognostic indicator for patients with endometrial carcinoma

We examined the usefulness of evaluating tumor size determined using preoperative magnetic resonance imaging (MRI) for prognosis in patients with endometrial carcinoma (EC). Patients (N = 184) with EC who underwent surgery at Shimane University Hospital between 1997 and 2013 were enrolled. We investigated the association between the tumor size of EC assessed prior to surgery by MRI (anteroposterior [AP], transverse [TV], and craniocaudal [CC] diameters) and various clinical parameters including deep myometrial invasion and lymph node metastases. We subsequently examined the prognostic significance of tumor size in patients with EC. Survival analysis was performed using the Kaplan-Meier method, and prognostic factors were evaluated using the Cox's proportional hazards regression model. Multivariate analysis identified increased AP diameter as an independent negative prognostic factor for overall survival (OS) (P = 0.037). A long AP diameter has prognostic value and the potential to be a predictive marker for surgical outcomes in patients with EC. Furthermore, AP diameter exhibited the greatest area under the curve (AUC) (0.727) for deep myometrial invasion, and CC diameter had the greatest AUC for lymph node metastases (0.854). Evaluation of tumor size parameters may aid in the identification of high-risk populations, which could improve treatment selection and patient outcomes.

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.

Current Status of Nephron-Sparing Surgery (NSS) in the Management of Renal Tumours

Nephron-sparing surgery has emerged as the surgical treatment of choice for small renal masses over the past two decades, replacing the traditional teaching of radical nephrectomy for renal cell carcinoma. With time, there has been an evolution in the techniques and indications for partial nephrectomy. This review summarizes the current status of nephron-sparing surgery for renal carcinoma and also deals with the future of this procedure.

Pattern formation in a nonlocal mathematical model for the multiple roles of the TGF-β pathway in tumour dynamics

The growth and invasion of cancer cells are very complex processes, which can be regulated by the cross-talk between various signalling pathways, or by single signalling pathways that can control multiple aspects of cell behaviour. TGF-β is one of the most investigated signalling pathways in oncology, since it can regulate multiple aspects of cell behaviour: cell proliferation and apoptosis, cell-cell adhesion and epithelial-to-mesenchimal transition via loss of cell adhesion. In this study, we use a mathematical modelling approach to investigate the complex roles of TGF-β signalling pathways on the inhibition and growth of tumours, as well as on the epithelial-to-mesenchimal transition involved in the metastasis of tumour cells. We show that the nonlocal mathematical model derived here to describe repulsive and adhesive cell-cell interactions can explain the formation of new tumour cell aggregations at positions in space that are further away from the main aggregation. Moreover, we show that the increase in cell-cell adhesion leads to fewer but larger aggregations, and the increase in TGF-β molecules - whose late-stage effect is to decrease cell adhesion - leads to many small cellular aggregations. Finally, we perform a sensitivity analysis on some parameters associated with TGF-β dynamics, and use it to investigate the relation between the tumour size and its metastatic spread.

Thermal ablative therapies for treatment of localised renal cell carcinoma: a systematic review of the literature

BACKGROUND AND AIMS

Small renal masses are commonly diagnosed incidentally. The majority are malignant and require intervention. The gold standard treatment is partial nephrectomy unless the patient has significant co-morbidities when surveillance or ablative therapies are utilised. The latter are relatively novel and their long-term efficacy and safety remain generally poorly understood. We performed a literature review to establish the current evidence on the oncological outcome of thermal ablative techniques in small renal masses treatment.

METHODS AND RESULTS

A systematic literature search was performed using PubMed, supplemented with additional references. Articles were reviewed for data on indications, tumour characteristics, ablative techniques, oncological outcome, impact on renal function and complications. The vast majority of articles identified were observational studies. There has not been any direct comparison against partial nephrectomy. Radiofrequency ablation and cryoablation are the techniques that are more commonly used. They have favourable oncological results on intermediate follow-up and indications that successful outcome is sustained long term. The morbidity and impact on renal function appear to be minimal.

CONCLUSION

Thermal ablative therapies are valid alternatives to partial nephrectomy for the treatment of small renal masses in patients unfit for surgery. Prospective long-term data will be needed before the indications for their use expand further.

Review of renal cell carcinoma and its common subtypes in radiology

Representing 2%-3% of adult cancers, renal cell carcinoma (RCC) accounts for 90% of renal malignancies and is the most lethal neoplasm of the urologic system. Over the last 65 years, the incidence of RCC has increased at a rate of 2% per year. The increased incidence is at least partly due to improved tumor detection secondary to greater availability of high-resolution cross-sectional imaging modalities over the last few decades. Most RCCs are asymptomatic at discovery and are detected as unexpected findings on imaging performed for unrelated clinical indications. The 2004 World Health Organization Classification of adult renal tumors stratifies RCC into several distinct histologic subtypes of which clear cell, papillary and chromophobe tumors account for 70%, 10%-15%, and 5%, respectively. Knowledge of the RCC subtype is important because the various subtypes are associated with different biologic behavior, prognosis and treatment options. Furthermore, the common RCC subtypes can often be discriminated non-invasively based on gross morphologic imaging appearances, signal intensity on T2-weighted magnetic resonance images, and the degree of tumor enhancement on dynamic contrast-enhanced computed tomography or magnetic resonance imaging examinations. In this article, we review the incidence and survival data, risk factors, clinical and biochemical findings, imaging findings, staging, differential diagnosis, management options and post-treatment follow-up of RCC, with attention focused on the common subtypes.

Risk of metastasis for T1a renal cell carcinoma

INTRODUCTION

While active surveillance for small renal mass is gaining acceptance, controversy still continues on true metastatic potential of small renal cell carcinoma (RCC). Thus, we investigated the risks of synchronous/metachronous metastases and their potential predictors among T1a RCC patients who underwent surgical treatment.

METHODS

We reviewed data from 2114 patients who received radical or partial nephrectomy for small renal tumor (≤ 4 cm) from 1990 to 2013. For our study, patients were stratified into four different groups according to tumor size (group 1: 0-1.0 cm, group 2: 1.1-2.0 cm, group 3: 2.1-3.0 cm, group 4: 3.1-4.0 cm). Univariate and multivariate analyses were performed to analyze metastatic potentials according to tumor size and identify useful predictors of metastases.

RESULTS

Among 1913 T1a RCC patients, there were low but nonnegligible rates of metastases (group 2: 1.1 %, group 3: 3.3 %, group 4: 6.0 %, respectively). Kaplan-Meier analysis showed significant differences in metastasis-free survivals between groups (p < 0.001). A linear positive association was observed between tumor size and metastatic rate (p < 0.001). Diabetic T1a RCC patients showed significantly inferior metastasis-free survival than nondiabetic counterparts (p = 0.003). Multivariate analysis revealed that tumor size and history of diabetes mellitus were independently associated with metastasis in T1a RCC.

CONCLUSIONS

As T1a RCCs present low but nonnegligible risk of metastasis, patients with small renal mass should be counseled on such risk when offered active surveillance. Larger tumor size and history of diabetes mellitus may be associated with higher risk of metastasis in T1a RCC.

The management of small renal masses: what is likely to change?

The diffusion of imaging has determined an increased discovery of small renal masses (SRMs). Recent publications have been reviewed to present the state of the art in the management of SRMs and to try to foresee the next steps in this challenging condition. The role of percutaneous biopsies is expanding, since management algorithms include also active surveillance and ablative therapies. However up to 30% of biopsies fail to provide histological diagnosis and there is the risk of under-evaluating high-grade tumors. Active surveillance has been proposed in patients with reduced life expectancy and numerous comorbidities. The average growth of SRMs is slow, and metastatic progression has been observed in about 1%. Ablative therapies (cryotherapy and radiofrequency ablation) are used in patients with relevant comorbidities or advanced age and unfit for surgery, but who desire active treatment. Compared to conservative surgical treatment both techniques have increased local progression rates, while metastatic progression is relatively low.Partial nephrectomy (PN) is the recommended curative treatment for SRMs and can be performed open, laparoscopically or robotically. Open PN represents the benchmark, with similar cancer specific survival and better preservation of renal function compared to nephrectomy. Laparoscopy is comparable to open surgery in terms of oncologic results, but a long learning curve is necessary. Perioperative outcomes of robot-assisted PN appear superior to laparoscopy and the learning curve is shorter, but data for oncological results are still immature. With the increasing diffusion of robotic technology it is likely more SRMs will be managed with this approach.

The impact of three-dimensional tumor volume on cancer-specific survival for patients with pT1 clear-cell renal cell carcinoma

PURPOSE

To evaluate the impact of three-dimensional tumor volume on cancer-specific survival for patients with pT1 clear-cell renal cell carcinoma (ccRCC).

MATERIALS AND METHODS

We reviewed a prospectively maintained database of 917 patients who underwent radical nephrectomy or nephron-sparing surgery for unilateral, pT1 ccRCC, including 654 pT1a and 263 pT1b patients, between April 1997 and December 2010. Three-dimensional tumor volume was measured using specialized volumetric software on cross-sectional computed tomography images of a preoperative venous phase. Kaplan-Meier and Cox regression analyses were carried out.

RESULTS

The median age was 54 years with a follow-up of 60.8 months. Median tumor size and volume were 3.2 cm and 17.4 cm(3), respectively. Of 917 patients, 54 (5.9 %) had died, including 32 patients with ccRCC (9 patients in pT1a and 23 patients in pT1b). On multivariate analysis, tumor size >3.2 cm and tumor volume >17.4 cm(3) were associated with cancer-specific death in pT1 ccRCC patients. When stratified by pT1a/pT1b status and analyzed on median splits, tumor size >2.5 cm was associated with cancer-specific death but not tumor volume >9.5 cm(3) in pT1a patients. However, in pT1b patients, tumor volume >62.1 cm(3) (P = 0.036, HR 2.91, 95 % CI 1.02-7.77) was highly associated with cancer-specific death but not tumor size >5.0 cm (P = 0.159, HR 1.91, 95 % CI 0.78-4.70).

CONCLUSIONS

In addition to tumor size, tumor volume is associated with cancer-specific death in pT1 ccRCC patients, particularly in pT1b ccRCC but not in pT1a ccRCC.

Current status of renal biopsy for small renal masses

Small renal masses (SRMs) are defined as radiologically enhancing renal masses of less than 4 cm in maximal diameter. The incidence of renal cell carcinoma (RCC) has increased in recent years, which is mainly due to the rise in incidental detection of localized SRMs. However, the cancer-specific mortality rate is not increasing. This discrepancy may be dependent on the indolent nature of SRMs. About 20% of SRMs are benign, and smaller masses are likely to have pathologic characteristics of low Fuhrman grade and clear cell type. In addition, SRMs are increasingly detected in elderly patients who are likely to have comorbidities and are a high-risk group for active treatment like surgery. As the information about the nature of SRMs is improved and management options for SRMs are expanded, the current role of renal mass biopsy for SRMs is also expanding. Traditionally, renal mass biopsy has not been accepted as a standard diagnostic tool in the clinical scenario because of several issues about safety and accuracy. However, current series on SRM biopsy have reported high diagnostic accuracy with rare complications. Studies of modern SRM biopsy have reported diagnostic accuracy greater than 90% with very high specificity. Also, current series have shown very rare morbid cases caused by renal mass biopsy. Currently, renal biopsy of SRMs can be recommended in most cases except when patients have imaging or clinical characteristics indicative of pathology and in cases in which conservative management is not considered.

The impact of tumour size on the probability of synchronous metastasis and survival in renal cell carcinoma patients: a population-based study

BACKGROUND

The observed low metastatic potential and favorable survival of small incidentally detected renal cell carcinomas (RCCs) have been a part of the rationale for recommending partial nephrectomy as a first treatment option and active surveillance in selected patients. We examined the relationship between tumor size and the odds of synchronous metastases (SMs) (primary outcome) and disease specific survival (secondary outcome) in a nationwide RCC registry.

METHODS

Retrospective study of the 794 RCC patients diagnosed in Iceland between 1971 and 2005. Histological material and TNM staging were reviewed centrally. The presence of SM and survival were recorded. Cubic spline analysis was used to assess relationship between tumor size and probability of SM. Univariate and multivariate statistics were used to estimate prognostic factors for SM and survival.

RESULTS

The probability of SM increased in a non-linear fashion with increasing tumor size (11, 25, 35, and 50%) for patients with tumors of ≤4, 4.1-7.0, 7.1-10.0, and >10 cm, respectively. On multivariate analysis, tumor size was an independent prognostic factor for disease-specific survival (HR = 1.05, 95% CI 1.02-1.09, p < 0.001), but not for SM.

CONCLUSION

Tumor size affected the probability of disease-specific mortality but not SM, after correcting for TNM staging in multivariate analysis. This confirms the prognostic ability of the 2010 TNM staging system for renal cell cancer in the Icelandic population.

Preoperatively misclassified, surgically removed benign renal masses: a systematic review of surgical series and United States population level burden estimate

PURPOSE

A significant proportion of renal masses removed for suspected malignancy are histologically benign with the probability inversely proportional to lesion size. To our knowledge the number of preoperatively misclassified benign renal masses treated with nephrectomy is currently unknown. Given the increasing incidence and decreasing average size of renal cell carcinoma, this burden is likely increasing. We estimated the population level burden of surgically removed, preoperatively misclassified benign renal masses in the United States.

MATERIALS AND METHODS

We systematically reviewed the literature for studies of pathological findings of renal masses removed for suspected renal cell carcinoma based on preoperative imaging through July 1, 2014. We excluded studies that did not describe benign pathology and with masses not stratified by size, and in which pathology results were based on biopsy. SEER data were queried for the incidence of surgically removed renal cell carcinomas in 2000 to 2009.

RESULTS

A total of 19 studies of tumor pathology based on size met criteria for review. Pooled estimates of the proportion of benign histology in our primary analysis (American studies only and 1 cm increments) were 40.4%, 20.9%, 19.6%, 17.2%, 9.2% and 6.4% for tumors less than 1, 1 to less than 2, 2 to less than 3, 3 to less than 4, 4 to 7 and greater than 7, respectively. The estimated number of surgically resected benign renal masses in the United States from 2000 to 2009 increased by 82% from 3,098 to 5,624.

CONCLUSIONS

These estimates suggest that the population level burden of preoperatively misclassified benign renal masses is substantial and increasing rapidly, paralleling increases in surgically resected small renal cell carcinoma. This study illustrates an important and to our knowledge previously unstudied dimension of overtreatment that is not directly quantified in contemporary surveillance data.

Solid renal masses: what the numbers tell us

OBJECTIVE

Solid renal masses are most often incidentally detected at imaging as small (≤ 4 cm) localized lesions. These lesions comprise a wide spectrum of benign and malignant histologic subtypes, but are largely treated with surgical resection given the limited ability of imaging to differentiate among them with consistency and high accuracy. Numerous studies have thus examined the ability of CT and MRI techniques to separate benign lesions from malignancies and to predict renal cancer histologic grade and subtype. This article synthesizes the evidence regarding renal mass characterization at CT and MRI, provides diagnostic algorithms for evidence-based practice, and highlights areas of further research needed to drive imaging-based management of renal masses.

CONCLUSION

Despite extensive study of morphologic and quantitative criteria at conventional imaging, no CT or MRI techniques can reliably distinguish solid benign tumors, such as oncocytoma and lipid-poor angiomyolipoma, from malignant renal tumors. Larger studies are required to validate recently developed techniques, such as diffusion-weighted imaging. Evidence-based practice includes MRI to assess renal lesions in situations where CT is limited and to help guide management in patients who are considered borderline surgical candidates.

Restored kidney graft from urologist referrals for renal transplantation

BACKGROUND

A new transplantation program using kidneys after a small tumor excision was initiated in Western Australia in February 2007. The aim of this study was to report the outcomes over 5 years.

METHODS

Local urologists were encouraged to refer the kidney to the transplantation service when considering a radical nephrectomy. Recipients are selected according to strict criteria. Between February 2007 and February 2012 24 of 30 referred kidneys were restored for transplantation. Average donor age was 53.4 (range, 32-75) years while the recipients were 66.3 (range, 57-80) years. Twenty-one kidneys were restored after excision of a small tumor (<3.3 cm) and 3 kidneys were restored after being obtained from patients who had experienced complicated ureteric injuries secondary to laparotomy and colectomy.

RESULTS

Nineteen of 24 grafts displayed immediate function, 4 had delayed function, and 1 had nonfunction. The first 3 patients developed urinary leakages, which all resolved by subsequent management. One graft showed a pseudoaneurysm on the day 1 Doppler ultrasound, requiring interventional embolization. All patients but 1 have been off dialysis with satisfactory graft function; creatinine (Cr) levels ranged from 70 μmol/L to 330 μmol/L. There was no tumor recurrence on close follow-up from 6 to 55 months (median, 26). Three patients died due to other medical issues.

CONCLUSION

Kidneys could be restored from urologic disease for transplantation after excision of a small tumor with satisfactory outcomes at an average follow-up of 26 months. Frozen section is necessary to ensure the clearance of the tumor prior to transplantation. A modification of the surgical technique has minimized urine leakage and pseudoaneurysm formation after tumor resection.

Small renal cell carcinomas--how dangerous are they really? Results of a large multicenter study

AIM OF THE STUDY

Modern diagnostic ultrasound and cross-sectional imaging has enabled the detection of increasing numbers of renal tumours. The aim of this study was to investigate the tumour- and patient-specific characteristics and prognosis of small renal cell carcinomas (RCCs) after surgical resection.

METHODS

The study included 2197 patients who underwent surgical resection of histologically confirmed RCC ⩽ 4 cm between 1990 and 2011. Median (mean) follow-up was 56.2 (65.5) months.

RESULTS

At the time of surgery, tumours were staged as pT ⩾ 3a in 175 (8.0%) cases, 134 (6.2%) were poorly differentiated and 75 (3.5%) were metastasised. The larger the tumour size, the higher was the risk of presenting with stage pT ⩾ 3a (p<0.001), poor tumour differentiation (p = 0.004), microscopic vascular involvement (p = 0.001) and collecting system invasion (p = 0.03). The 5-year cancer-specific survival (CSS) rate was 93.8% for stage pT1a versus 79.4% for stage pT ⩾ 3a (p<0.001), and it was 93.7% for G1-2 versus 76.8% for G3-4 differentiation (p<0.001). Multivariate analysis identified age in years (hazard ratio (HR) 1.04, p<0.001), metastatic disease (HR 12.5, p < 0.001), tumour differentiation (HR 2.8, p<0.001) and non-clear cell histology (HR 0.51, p = 0.02) as independent prognosticators for CSS in patients with small RCC. Interestingly, the 5-year cancer-specific mortality rate for pT1a N/M0 patients was 5.8%.

CONCLUSIONS

This large multicenter study has clearly shown that, though most small RCC have a low pathological stage and a good prognosis, there is also a small but significant subgroup of these tumours that are already locally advanced or poorly differentiated.

Small renal masses: surgery or surveillance

The incidence of kidney cancer has been rising over the past two decades, especially in cases in which the disease is localized and small in size (<4 cm). This rise is mainly due to the widespread use of routine abdominal imaging such as ultrasonography, computed tomography, and magnetic resonance imaging. Early detection was initially heralded as an opportunity to cure an otherwise lethal disease. However, despite increasing rates of renal surgery in parallel to this trend, mortality rates from renal cell carcinoma have remained relatively unchanged. Moreover, data suggest that a substantial proportion of small renal masses are benign. As a result, the management of small renal masses has continued to evolve along two basic themes: it has become less radical and less invasive. These shifts are in part a reflection of an improved understanding that the biology of incidentally discovered renal cell carcinoma may be more indolent than previously thought. However, not all small renal masses are indolent, and de novo metastatic disease can develop at the initial presentation. Therefore, it is with this background of clinical uncertainty and biological heterogeneity that clinicians must interpret the benefits and disadvantages of various clinical approaches to small renal masses.

[Active surveillance: concept for renal cell carcinoma?]

More than 80% of renal cell carcinomas are currently being detected incidentally by ultrasonic imaging and often affect elderly patients with substantial comorbidities. Surgical options cannot be applied in this cohort as routinely as in younger patients, as in some cases the perioperative risk factors may outweigh the risk of tumor-related death. In this context the concept of active surveillance for localized renal cell cancer in elderly patients is becoming increasingly important. The aim of active surveillance is to avoid surgery-related adverse effects and to achieve a controlled observation of tumor behavior with an option of delayed intervention in cases of aggressive clinical tumor features. This review sheds light on the current status of this strategy.

[Partial nephrectomy. Rationale and limitations of an organ-preserving approach]

The rising incidence of renal cell cancer in recent decades has led to a revision in the therapy of this malignancy. For small renal masses, partial nephrectomy has become the standard surgical treatment instead of radical nephrectomy. This approach can lead to a higher overall survival due to preservation of renal function. Avoiding chronic kidney disease is mandatory for patients with benign or small non-aggressive tumors; however, partial nephrectomy correlates with higher complication rates and is conditioned by operator skills. The role of partial nephrectomy compared to radical nephrectomy is still to be established particularly for larger tumors. The results of studies so far are mostly based on non-randomized retrospective data. This article will present the pros and cons of partial nephrectomy and will focus on the steps required to promulgate the indications of nephron-sparing surgery.

Accuracy of determining small renal mass management with risk stratified biopsies: confirmation by final pathology

PURPOSE

We assess the accuracy of a biopsy directed treatment algorithm in correctly assigning active surveillance vs treatment in patients with small renal masses by comparing biopsy results with final surgical pathology.

MATERIALS AND METHODS

From 1999 to 2011, 151 patients with small renal masses 4 cm or smaller underwent biopsy and subsequent surgical excision. Biopsy revealed cell type and grade in 133 patients, allowing the hypothetical assignment of surveillance vs treatment using an algorithm incorporating small renal mass size and histological risk group. We compared the biopsy directed management recommendation with the ideal management as defined by final surgical pathology.

RESULTS

Biopsy called for surveillance of 36 small renal masses and treatment of 97 small renal masses. Final pathology showed 11 patients initially assigned to surveillance should have been assigned to treatment (8.3% of all patients, 31% of those recommended for surveillance), whereas no patients moved from treatment to surveillance. Agreement between biopsy and final pathology was 92%. Using management based on final pathology as the reference standard, biopsy had a negative predictive value of 0.69 and positive predictive value 1.0 for determining management. Of the 11 misclassified cases, 7 had a biopsy indicating grade 1 clear cell renal cancer which was upgraded to grade 2 (5) or grade 3 (2). After modifying the histological risk group assignment to account for undergrading of clear cell renal cancer, agreement improved to 97%, with a negative predictive value of 0.86 and a positive predictive value of 1.0.

CONCLUSIONS

Our results suggest that compared to final pathology, biopsy of small renal masses accurately informs an algorithm incorporating size and histological risk group that directs the management of small renal masses.

Thermoablation of Renal Masses: The Urologist's Perspective

Thermoablation (TA) has become an increasingly popular treatment for small renal masses (SRMs). Although long-term outcomes are not currently reported, TA may have a role in being an alternative to radical or partial nephrectomy. This review gives a broad overview of TA and discusses current controversies in the field.

Potential role of (124)I-girentuximab in the presurgical diagnosis of clear-cell renal cell cancer

Renal cell carcinoma (RCC) is a biologically heterogeneous disease, with many small renal masses (SRMs) exhibiting an indolent natural history, while others progress more rapidly to become life-threatening. Existing multiphase contrast-enhanced imaging methods, such as computed tomography or magnetic resonance imaging, cannot definitively distinguish between benign and malignant solid tumors or identify histologic subtype, and early results of molecular imaging studies (positron emission tomography [PET]) in the evaluation of SRMs have not improved on these established modalities. Alternative molecular markers/agents recognizing aberrant cellular pathways of cellular oxidative metabolism, DNA synthesis, and tumor hypoxia tracers are currently under development and investigation for RCC assessment, but to date none are yet clinically applicable or available. In contrast, immuno-PET offers highly selective binding to cancer-specific antigens, and might identify radiographically recognizable and distinct molecular targets. A phase I proof-of-concept study first demonstrated the ability of immuno-PET to discriminate between clear-cell RCC (ccRCC) and non-ccRCC, utilizing a chimeric monoclonal antibody to carbonic anhydrase IX (cG250, girentuximab) labeled with ¹²⁴I (¹²⁴I-girentuximab PET); the study examined patients with renal masses who subsequently underwent standard surgical resection. A follow-up phase III multicenter trial confirmed that ¹²⁴I-cG250-PET can accurately and noninvasively identify ccRCC with high sensitivity (86%), specificity (87%), and positive predictive value (95%). In the challenge to appropriately match treatment of an incidentally identified SRM to its biological potential, this highly accurate and histologically specific molecular imaging modality demonstrates the ability of imaging to provide clinically important preoperative diagnostic information, which can result in optimal and personalized therapy.