Increased incidental detection and reduced mortality in renal cancer--recent retrospective analysis at eight institutions

Presumed radically treated renal cell carcinomaRecurrence of the disease and prognostic factors for subsequent survival

OBJECTIVE

To gain knowledge about when, where and how metastases after presumed radical treatment for renal cell carcinoma (RCC) are detected, and to use this information to establish a follow-up programme for radically treated RCC. Further aims were to establish survival rates, together with identifying prognostic factors influencing survival for different groups of patients after recurrence of the disease.

MATERIAL AND METHODS

A retrospective study of 305 pT1-4N0M0/pT1-4NxM0 (clinically N0) tumours treated with nephrectomy was performed.

RESULTS

A total of 89 patients (29.2%) developed metastases, with a median time to recurrence of 25.1 months. Within 5 years, 80% of the metastases had been detected. The lungs were the commonest metastatic site. A total of 34.8% of the recurrences were diagnosed as a result of routine follow-up. Median cancer-specific survival (CSS) after recurrence was 9.8 months. For patients with a disease-free interval (DFI) > or =24 months the median CSS was 35 months. In a univariate analysis, performance status, DFI > or =24 months, metastases in a single organ, primary tumour size < or =70 mm, primary tumour stage pT1-2 and age <65 years were all associated with better survival. In a multivariate analysis, performance status, DFI and number of organs affected were independent predictors of survival.

CONCLUSION

The information from this material is used to suggest a simple, but adequate, follow-up protocol. Easily accessible information can be used to identify groups with different prognoses regarding survival after recurrence of the disease.

Biopsy of renal masses: when and why

Percutaneous image-guided biopsy of renal masses is a safe and accurate procedure. Although once reserved for the diagnosis of unresectable renal cell carcinoma, metastases, lymphoma, and infection, today percutaneous image-guided biopsy has an expanded role. There is increasing awareness that a substantial proportion of small, solid renal masses are benign neoplasms. Although imaging can be used to diagnose most of them, some are incorrectly believed to represent renal cell carcinoma and unnecessary surgery may be performed. Based largely on advances in cytological techniques, percutaneous biopsy can be now be used to diagnose benign neoplasms and thus prevent them from being treated unnecessarily. Concurrent advances in percutaneous ablation have also promoted its use. As a result, there are 8 established indications for percutaneous biopsy, and reason to believe that the number of indications will expand further in the future.

Surveillance of urothelial carcinoma: stage and grade migration, 1993-2005 and survival trends, 1993-2000

BACKGROUND

Previous investigators have detected shifts to lower stages at diagnosis for renal cell carcinoma and prostate cancer. The authors investigated whether a similar pattern is seen for urothelial carcinomas of the bladder, ureter, and renal pelvis and sought to identify changes in cancer grade and survival trends from 1993 to 2005.

METHODS

The National Cancer Data Base (NCDB) collects data on approximately 75% of all newly diagnosed cancer cases annually. The authors queried the database for cases of urothelial carcinomas diagnosed in 1993-2005 in patients aged 18 years and older. All cancer stage data were forward converted to the sixth edition of the American Joint Committee on Cancer staging definitions.

RESULTS

A total of 334,480 bladder cancer cases, 15,105 renal pelvis cancer cases, and 10,128 ureteral carcinoma cases were identified. Stage data were available for 84% of bladder cases, 83% of renal pelvis cases, and 82% of ureter cases. With the classification of early stage tumors as stage 0a, 0is, and I and late stage tumors as II, III, and IV, the percentage of early stage renal pelvis and ureter tumors increased slightly from 1993 to 2005, whereas no stage migration was seen in bladder tumors. In looking specifically at early stage tumors, a significant increase in the proportion of stage 0a and a significant decrease in the proportion of stage I tumors for each cancer site was seen between 1993 and 2005. The proportion of high grade tumors in each disease site significantly increased from 1993 to 2005. For cases diagnosed in 1993-1996 and 1997-2000, a significant decrease in 5-year relative survival was observed for patients with stage I and stage II bladder cancer. The absolute change, however, was relatively small, and for bladder cases was not significantly different when adjusted for low or high grade tumors.

CONCLUSIONS

When differentiating between early and late stage tumors, a slight stage migration was seen in renal pelvis and ureteral carcinomas, whereas no stage migration was seen in bladder tumors. Within early stage tumors of all sites, a stage shift was seen, most notably with the proportion of stage 0a tumors increasing and stage I tumors decreasing. The proportion of high grade tumors in all sites increased. No change in overall survival was observed, underscoring the need for new therapeutic advances.

Renal oncocytoma: CT features cannot reliably distinguish oncocytoma from other renal neoplasms

AIM

To retrospectively review the computed tomography (CT) imaging features of a series of histologically confirmed renal oncocytomas and to determine whether imaging features are predictive of this subtype of benign renal epithelial tumour.

MATERIALS AND METHODS

From May 2001 to October 2007, 21 patients with 28 renal masses, confirmed as renal oncocytoma on histological examination of the resection specimen, were identified from the pathology database at our institution. The preoperative imaging findings were retrospectively analysed to determine characteristic features, if any, to predict this rare subtype of benign renal tumour.

RESULTS

There were 11 female and 10 male patients and the age at presentation ranged from 40-80 years (mean age 65.9 years). The size of the masses ranged from 1.2-12 cm in diameter (mean diameter 4.9 cm). All masses showed contrast enhancement. In 18 (64.3%) lesions the enhancement of the tumour was isodense to renal cortex. Ten (35.7%) lesions were hypodense to renal cortex. In three (10.7%) lesions, a well-defined stellate central scar was seen at CT and confirmed pathologically. In two (7.1%) lesions, a central scar was identified pathologically, but not seen on CT. The size of the central scars ranged from 10-29 mm diameter on CT. Twenty-two (78.6%) lesions did not demonstrate a scar on CT or pathologically. None of the patients had regional lymphadenopathy or distant metastasis.

CONCLUSION

Renal oncocytoma is typically described as being hypervascular and homogeneous, with a characteristic central stellate scar on CT. The present study demonstrates that these imaging features are found in only a small proportion of these tumours. Therefore, imaging characteristics alone are unreliable when differentiating between oncocytoma and renal cell carcinoma, and histopathological diagnosis remains the reference standard.

Thermal ablation: update and technique at a high-volume institution

In the era of nephron-sparing surgery for small renal tumors, thermal ablation is gaining popularity. Both cryoablation and radiofrequency ablation have well-demonstrated short-term oncologic efficacy and safety. This article shares the current literature and the radiofrequency ablation technique at a high-volume institution. Cases are presented that illustrate solutions to obstacles frequently encountered during percutaneous ablation of renal masses.

Epidemiology, clinical staging, and presentation of renal cell carcinoma

The increasing incidence of renal cell carcinoma over the past 2 decades can be partly explained by the expanding use of abdominal imaging. As a result, the most incident renal cancers today are small, localized, and asymptomatic. However, the well-documented rise in all stages of RCC calls into question the nature of these asymptomatic lesions. The expected "screening effect" of detecting RCC when it is small and localized, with subsequent decreases in disease-specific mortality, has not been observed. Disease-specific mortality is actually rising, especially in African American patients. Effective interventions aimed at reducing obesity, hypertension, and smoking may help in reducing the incidence of RCC in the future.

The haphazard approach to the early detection of asymptomatic renal cancer: results from a contemporary executive health programme

OBJECTIVE To compare the detection of asymptomatic renal cell carcinoma (RCC) in an executive health programme (EHP) that uses traditional methods of screening (history, physical examination and urine analysis) to programmes that screen by renal imaging. PATIENTS AND METHODS We retrospectively reviewed case records from patients undergoing executive health examinations at Mayo Clinic between 1 January 2002 and 30 September 2007. Results Of 32 310 patients, 18 RCCs were detected; of these, 13 (72%) were detected by the EHP and five (28%) were missed by the initial EHP screening process but subsequently discovered within 4-24 months. Of the 13 detected through the EHP, eight were discovered incidentally, two because of symptoms, and three because of asymptomatic microscopic haematuria (AMH). Of the 13, 12 were classified as early-stage cancers (Stage I). By contrast, of the five cancers missed by the EHP screening process, two were diagnosed because of the development of symptoms and only one was classified as Stage I. To date, two of these patients whose cancers were undetected by the EHP developed metastasis and one of them has died. Both had been followed in the EHP for years and neither had MH in multiple specimens. CONCLUSION Our EHP follows standard policy and relies on a history, physical examination and urine analysis to decide who to evaluate for asymptomatic RCC. This practice missed >70% of the potentially diagnosable cancers. The patients with RCCs that were discovered initially by the EHP fared better than those whose diagnosis was delayed. Our detection rate of four per 10 000 was only a fraction of those reported by programmes using imaging as a screening tool. The logic behind our current approach to the early detection of asymptomatic RCC needs to be reassessed. AMH is coincidental in most cases and patients could forego imaging if they are unsuitable candidates for screening. However, AMH will miss most treatable cancers and is not an appropriate screening test for an early detection programme. In the absence of reliable biomarkers, renal imaging should be the primary screening tool for detecting asymptomatic RCC in informed, clinically suitable individuals enrolled in an early detection programme.

Disparities in the treatment of patients with IL-2 for metastatic renal cell carcinoma

OBJECTIVES

The incidence of metastatic renal cell cancer (mRCC) is rising. To date, interleukin-2 (IL-2) is the only treatment offering a complete response rate for mRCC. We wish to test the hypothesis that the combination of restricted availability and expense associated with IL-2 administration results in differential access to the medication based on race and sex, despite similar clinical indications for its use.

METHODS

We used data from the Surveillance, Epidemiology, and End Results program and the Centers for Medicare Services (CMS) to clinically characterize subjects with mRCC diagnosed from 1992 through 2002. We linked these subjects to claims identified in the CMS databases. We then assigned subjects to cohorts receiving radical nephrectomy, IL-2, both, or neither. A logistic model was created to identify factors that had significant independent effects on the receipt of IL-2.

RESULTS

Three thousand seven hundred thirty individuals were identified with mRCC. After controlling for other variables, female subjects were less likely to receive IL-2 (O.R. 0.80). African American subjects were also less likely to receive IL-2 (O.R 0.55). Married individuals were much more likely to receive IL-2 (O.R 1.9).

CONCLUSIONS

African Americans and women were much less likely to be treated with IL-2 after controlling for relevant clinical variables. These data document that the only therapy offering a complete response to patients with mRCC is less frequently given to those who are African American or female. It is possible that the racial and gender-based disparities in treatment with IL-2 will be replicated with newer, expensive treatment options for mRCC. Further prospective investigation into mitigating barriers to receipt of effective care for mRCC is urgently needed.

Cyclooxygenase-2 expression: does it have a probable role in tumorigenesis mechanisms of renal cell carcinoma?

OBJECTIVES

The purpose of this study was to evaluate the correlation between the levels of cyclooxygenase-2 (COX-2) expression with clinicopathologic features and determine the impact on prognosis in patients with renal cell carcinoma (RCC).

METHODS

Expression of COX-2 was evaluated immunohistochemically in RCC tissues from 62 patients who underwent radical nephrectomy between 1996 and 2004. Percentage of COX-2 staining was scored as 0 (negative), 1 (1-24%), 2 (25-49%), 3 (50-74%), and 4 (75-100%). Immunohistochemical COX-2 staining score (ISS) was defined as summation of intensity and percentage of COX-2 staining.

RESULTS

Twenty-seven patients (43.5%) with a median follow-up of 47.8 (25-115) months stained positively for COX-2. COX-2 expression was positive in 37.1%, 50%, and 66.7% of patients with stages 1, 2, and 3, respectively (P = 0.46). Correlation between ISS and pathological stage was statistically significant (P = 0.005). Multivariate regression analysis revealed no clinicopathologic parameter as independent predictors of progression. Kaplan-Meier analysis revealed statistically significant different survival rates in tumor stage, grade, and ISS.

CONCLUSION

Although COX-2 expression is not an independent predictor of progression in patients with RCC, patients with higher ISS values have significantly shorter progression-free survival rates. These results might be important to the clinician because positive COX-2 expression of a certain RCC might necessitate early adjuvant systemic therapy to delay the progression of RCC. For this reason, there is a need for innovative, prospective, and randomized studies in patients with positive COX-2 expression that will display the impact of systemic therapies in these patients.

Survival rates after resection for localized kidney cancer: 1989 to 2004

BACKGROUND

Mortality rates from kidney cancer have continued to rise despite increases in the detection of smaller renal tumors and rates of renal surgery. To explore the factors associated with this treatment-outcome discrepancy, the authors evaluated how changes in tumor size have affected disease progression in patients after nephrectomy for localized kidney cancer, and they sought to identify the factors associated with disease progression and overall patient survival after resection for localized kidney cancer.

METHODS

In total, 1618 patients with localized kidney cancer were identified who underwent nephrectomy at Memorial Sloan-Kettering Cancer Center from 1989 to 2004. Patients were categorized by year of surgery: from 1989 to 1992, from 1993 to 1996, from 1997 to 2000, and from 2001 to 2004. Tumor size was classified according to the following strata: <2 cm, from 2 cm to 4 cm, from 4 cm to 7 cm, and >7 cm. Disease progression was defined as the development of local recurrence or distant metastases. Five-year progression-free survival (PFS) was calculated for patients in each tumor size strata according to the year of operation using the Kaplan-Meier method. The patient-, tumor-, and surgery-related characteristics associated with PFS and overall survival (OS) were explored using univariate analysis, and all significant variables were retained in a multivariate Cox regression analysis.

RESULTS

Overall, the number of nephrectomies increased for all tumor size categories from 1989 to 2004. A tumor size migration was evident during this period, because the proportion of patients with tumors <2 cm and with tumors from 2 cm to 4 cm increased, whereas the proportion of patients with tumors >7 cm decreased. One hundred seventy-nine patients (11%) developed disease progression after nephrectomy. Sixteen patients (1%) developed local recurrences, and 163 patients (10%) developed distant metastases. When 5-year PFS was calculated for each tumor size strata according to 4-year cohorts, trends in PFS did not improve or differ significantly over time. Compared with historic cohorts, patients in more contemporary cohorts were more likely to undergo partial nephrectomy rather than radical nephrectomy and were less likely to undergo concomitant lymph node dissection and adrenalectomy. Multivariate analysis demonstrated that pathologic stage and tumor grade were associated with disease progression, whereas patient age and tumor stage were associated with overall patient survival.

CONCLUSIONS

Despite an increasing number of nephrectomies and a size migration toward smaller tumors, trends in 5-year PFS and OS did not improve or differ significantly over time. These findings require further research to identify causative mechanisms, and they argue for the consideration of active surveillance for patients who have select renal tumors and a re-evaluation of the current treatment paradigm of surgically removing solid renal masses on initial detection.

Percutaneous renal cryoablation: current status

Over the last 13 years, renal cryoablation has emerged as a promising technique for the treatment of solid renal tumors. The improvement in imaging modalities such as ultrasound, computed tomography and MRI, as well as the introduction of thinner probes, has led to the spread of the minimally invasive percutaneous approach. We review the historical background of percutaneous renal cryoablation (PRC), present its basic principles, mention the contemporary clinical data and outcomes of this technique and suggest future directions for its wider application in renal tumors. Early results have demonstrated that it may offer an alternative for the treatment of small renal masses with the advantages of minimal complications, spared renal function, decreased overall costs and equivalent oncologic efficacy. Long-term results are required in order to apply this minimally invasive technique to a broader spectrum of patients.

Racial/ethnic and gender disparities in renal cell carcinoma incidence and survival

PURPOSE

We used a population based cancer registry to examine trends in renal cell carcinoma incidence and survival among 4 racial/ethnic groups (white, black, Hispanic and Asian/Pacific Islander) and both genders.

MATERIALS AND METHODS

Race/ethnicity, gender, age, staging, length of survival and cause of death data were analyzed using 39,434 cases of renal cell carcinoma from 1988 to 2004 from the California Cancer Registry. Annual age adjusted incidence rates and relative survival rates were calculated for the racial/ethnic and gender groups. These rates and the percent of localized cancer were plotted by year, and Microsoft Excel was used to calculate linear regression equations. Median age was also calculated. Z-tests and chi-square tests were performed to determine p values.

RESULTS

An increase in renal cell carcinoma incidence was found with localized cancer accounting for most of the increase. Black patients had a significantly higher incidence rate (p <0.0001) and lower survival rate (p <0.0001) than all other races/ethnicities despite having more localized cancer (p <0.005). Black patients were also diagnosed at a younger age (p <0.0001) than their counterparts. On the other hand Asian/Pacific Islanders had a lower incidence rate (p <0.0001) and higher survival rate (p <0.05) than all other races/ethnicities. Males had approximately twice the incidence rate of females and a lower survival rate (p <0.005).

CONCLUSIONS

Higher incidence rates and lower survival rates were identified among black and male patients compared to their counterparts, while Asian/Pacific Islanders showed the opposite trends. Such racial/ethnic and gender disparities in renal cell carcinoma incidence and survival may help elucidate biological, behavioral and environmental factors that can potentially be addressed.

Selecting clinically-driven biomarkers for cancer nanotechnology

The challenge of biomarker identification for bionanotechnology is that we need to find less than ten potential biomarkers from high throughput data so that quantum dot synthesis and imaging can be effective. Among all the extensive biomarker research, the novelty of our research is to reduce the number the biomarkers by studying the efficacy of several classifiers and error estimation methods. Specifically, we are using renal cancer expression data. The dataset consists of 31 microarray samples divided into four classes -- clear cell, oncocytoma/chromophobe, papillary, and angiomyolipoma. Each class is compared to all other classes using error estimation methods for support vector machines (SVM), Fisher's discriminant (FD), and signed distance function (SDF). Prior knowledge of significant biomarker from a previous study is used to score the effectiveness of each classifier in correctly identifying these biomarkers. We have achieved intelligent model selection for biomarker identification so that the total number of nano-imaging targets is small.

Cold saline irrigation of the renal pelvis during Radiofrequency Ablation of a central renal neoplasm: a case report

Introduction

Thermal destruction mediated by radiofrequency ablation (RFA) is gaining attention as an alternative treatment for patients with renal cell carcinoma (RCC), particularly in those who are not candidates for open surgery. Treatment of central tumours is occasionally associated with complications such as ureteric stricture, injury to the psoas muscle, haematuria and vascular laceration.

Case presentation

We have used infusion of cold saline during RFA, through a retrograde ureteric catheter with its tip in the renal pelvis, in a patient with a central renal tumour.

Conclusion

We believe this process to have successfully avoided the risk of thermal injury.

Renal epithelial neoplasms: diagnostic applications of gene expression profiling

Renal cell carcinoma (RCC) is the most common form of kidney cancer in adults. RCC is a significant challenge for pathologic diagnosis and clinical management. The primary approach to diagnosis is by light microscopy, using the World Health Organization (WHO) classification system, which defines histopathologic tumor subtypes with distinct clinical behavior and underlying genetic mutations. However, light microscopic diagnosis of RCC subtypes can be difficult due to variable histology, morphologic features shared by tumor subtypes, and a growing frequency of small tumor biopsies with limited morphologic information. In addition to these diagnostic problems, the clinical behavior of RCC is highly variable, and therapeutic response rates are poor. Few clinical assays are available to predict outcome in RCC or correlate behavior with histology. Therefore, novel RCC classification systems based on gene expression should be useful for diagnosis, prognosis, and treatment. Recent microarray studies have shown that renal tumors are characterized by distinct gene expression profiles, which can be used to discover novel diagnostic and prognostic biomarkers. Here, we review clinical features of kidney cancer, the WHO classification system, and the growing role of molecular classification for diagnosis, prognosis, and therapy of this disease.

Overexpression of the myc target gene Mina53 in advanced renal cell carcinoma

The myc target gene Mina53 was reported to be overexpressed in esophageal cancer with a poor prognosis. The purpose of the present study was to examined Mina53 expression and its relationship to clinicopathological parameters in human renal cell carcinoma (RCC). Mina53 and Ki-67 expression was examined on immunohistochemistry for 64 surgically resected RCC and non-cancerous tissue. In addition, the relationship between Mina53 expression and clinicopathological prognostic factors of RCC such as age, stage, microvenous invasion (MVI), histological subtype, Ki-67 labeling index (LI), and prognosis, was examined. Mina53 was expressed in the nuclei of tumor cells and tubular nuclei of normal renal tissue. The expression level of Mina53 was significantly higher in patients with poor prognostic factors (stage IV, MVI-positive, and sarcomatoid RCC, and high Ki-67 LI). The prognosis of high Mina53-expressing tumors was significantly poorer than that of non-Mina53-high tumors (P < 0.0001). In conclusion, Mina53 is overexpressed in RCC tissue from patients with poor prognostic factors, suggesting that Mina53 overexpression is one of the factors for poor prognosis in RCC.

Claudin-7 immunohistochemistry in renal tumors: a candidate marker for chromophobe renal cell carcinoma identified by gene expression profiling

CONTEXT

The differential diagnosis of eosinophilic renal tumors can be difficult by light microscopy. In particular, chromophobe renal cell carcinoma (RCC) is difficult to distinguish from oncocytoma. This differential diagnosis is important because chromophobe RCC is malignant, whereas oncocytoma is benign. Furthermore, chromophobe RCC has distinct malignant potential and prognosis compared with eosinophilic variants of other RCC subtypes. Immunohistochemistry is useful for distinguishing chromophobe RCC from other subtypes of renal carcinoma, but no expression marker reliably separates chromophobe RCC from oncocytoma.

OBJECTIVE

In a previous gene expression microarray analysis of renal tumor subtypes, we found the distal nephron markers claudin-7 and claudin-8 to be overexpressed in chromophobe RCC versus oncocytoma and other tumor subtypes. We have confirmed similar findings in independent microarray data and validated differential claudin-7 protein expression by immunohistochemistry.

DESIGN

Immunohistochemical analysis of claudin-7 in 36 chromophobe RCCs, 43 oncocytomas, 42 clear cell RCCs, and 29 papillary RCCs.

RESULTS

Membranous claudin-7 expression was detected in 67% chromophobe RCCs, compared with 0% clear cell RCCs, 28% papillary RCCs, and 26% oncocytomas (P < .001).

CONCLUSIONS

Based on microarray and immunohistochemical data, we propose claudin-7 to be a candidate expression marker for distinguishing chromophobe RCC from other renal tumor subtypes, including the morphologically similar oncocytoma. The clinical utility of claudin-7 should be validated in independent studies of renal tumors, possibly in combination with additional targets in a multiplex immunohistochemical panel.

Percutaneous radiofrequency ablation of renal tumours: Case series of 11 tumours and review of published work

Detection of renal cell carcinoma (RCC) is increasing with the greater use of cross-sectional imaging and up to two-thirds of RCCs are discovered incidentally in asymptomatic patients. The traditional option of nephrectomy or partial nephrectomy may not always be appropriate. A minimally invasive treatment alternative is radiofrequency ablation (RFA). We retrospectively reviewed the RFA cases for renal tumours at our institution between January 2004 and June 2006. Thirteen RFA treatment sessions were conducted for 11 neoplasms in 11 patients. Mean patient age was 74.4 years (61-88 years). Imaging was carried out after ablation with a mean follow up of 8.0 months (2-26 months). No residual tumour was observed after the first RFA treatment in 82% of patients (nine of 11). Two patients required a second RFA treatment for residual (one) or recurrent tumour (one). RFA is emerging as a useful technique for treatment of small renal tumour. A number of short-term studies reflect this, however, long-term findings are still lacking.

Prevalence of renal cell carcinoma: a nation-wide survey in Japan, 2002

OBJECTIVE

To investigate the incidence of renal cell carcinoma, classified by sex, age group and region in Japan, following a 5-year interval after a previous survey performed in 1997.

METHODS

The survey was conducted between the beginning of January 2002 and the end of December 2002. A total of 1288 institutions in all 47 prefectures throughout Japan were requested to register cases.

RESULTS

There were 7405 persons with renal cell carcinoma, consisting of 5063 males and 2342 females. Crude incidence rates were 8.2 and 3.6 per 100 000 population for men and women, respectively. Incidence rates in the Hokkaido region were highest followed by the Shikoku region.

CONCLUSIONS

Despite incidence of renal cell carcinoma increasing to 7405 from the 6358 persons in 1997, statistical data reported by the Ministry of Health, Labor and Welfare indicate that rising age-adjusted death rate for this tumor reached a ceiling in the past decade. Early detection may have contributed to this current trend; however, further epidemiological research is required to fully elucidate this.

Disparities in treatment and outcome for renal cell cancer among older black and white patients

PURPOSE

Black patients with renal cell cancer have shorter survival compared with their white counterparts, but the causes for this disparity are unclear. To elucidate reasons for this inequality, we examined differences in treatment and survival between black and white patients.

PATIENTS AND METHODS

A retrospective cohort study was conducted using data from the linked Surveillance, Epidemiology and End Results (SEER) cancer registry and Medicare databases. Participants included 964 black and 10,482 white patients age >or= 65 years who were enrolled into Medicare and diagnosed with renal cell cancer between 1986 and 1999. Information on surgical treatment was ascertained from both databases, whereas data regarding coexisting illness and survival was obtained from the Medicare database.

RESULTS

The percentage of black patients receiving nephrectomy treatment was significantly lower compared with whites (61.2% v 70.4%; P < .0001). After adjustment for age, sex, median income, cancer stage, tumor size, and comorbidity index, blacks were less likely to undergo nephrectomy treatment compared with whites (risk ratio = 0.93; 95% CI, 0.90 to 0.96). Overall survival was worse for blacks than whites even after adjustment for demographic and cancer prognostic factors (hazard ratio [HR] = 1.16; 95% CI, 1.07 to 1.25); however, additional adjustment for comorbidity index and nephrectomy treatment reduced the disparity substantially (HR = 1.00; 95% CI, 0.93 to 1.09).

CONCLUSION

This study indicates that the lower survival rate among blacks compared with whites with renal cell cancer can be explained largely by the increased number of comorbid health conditions and the lower rate of surgical treatment among black patients.

Combined Percutaneous Radiofrequency Ablation and Ethanol Injection of Renal Tumours: Midterm Results

OBJECTIVES

To evaluate the safety and efficacy of combined percutaneous, image-guided, radiofrequency (RF) ablation and ethanol injection of renal tumours, and to present our midterm results.

METHODS

Since February 2002, 27 consecutive patients (22 men, 5 women; age range: 39-84 yr; mean: 69) with 28 renal tumours (mean diameter: 2.87cm) were treated with combined percutaneous RF and ethanol ablation, and were prospectively evaluated. Twenty-five patients were considered nonsurgical candidates because of comorbid conditions (16 patients) or had previous nephrectomy (9 patients), and 2 had refused surgery. Thirty-three ablation sessions were performed, with computed tomography (26 sessions), ultrasound (6), or combined magnetic resonance imaging/fluoroscopic guidance in 1. Absolute ethanol (0.5-3ml; mean: 1.7) was injected into the tumour immediately before treatment with radiofrequency. Mean follow-up period was 18.6 mo (range: 3-56).

RESULTS

Twenty-seven of the 28 tumours were completely ablated with either one (21 tumours) or two treatment sessions (6 tumours). One patient with residual disease refused further treatment. Only three minor complications, including a subcapsular haematoma and two patients with loin pain, occurred; all three patients were treated conservatively. None of the complications was related to the ethanol injection. During the follow-up period, no evidence of local recurrence or metastatic disease was seen. Creatinine levels have not changed significantly in any of the patients following ablation.

CONCLUSIONS

Combined use of percutaneous RF and ethanol ablation is a safe and effective alternative treatment for selective patients with renal tumours.

Ablative techniques for the management of kidney cancer

For lesions smaller than 4 cm, nephron-sparing surgery has been shown to be oncologically equivalent to radical nephrectomy, albeit with the advantage of preservation of overall renal function. As such, partial nephrectomy became the first-line treatment option for localized, small renal masses. Minimally invasive options associated with limited morbidity--such as probe-ablative procedures--are, however, being investigated in selected patients for whom invasive, nephron-sparing surgery (whether laparoscopic or open) is undesirable. The main probe-ablative techniques being investigated as alternatives to partial nephrectomy are cryoablation, radiofrequency ablation, and high-intensity focused ultrasound. Advances in imaging, ablative system technologies, and early evidence that in situ tumor ablation can yield comparable results to those achieved with tumor resection in selected cases, have sparked significant interest in these minimally invasive techniques.

Diagnostic yield of 58 consecutive imaging-guided biopsies of solid renal masses: should we biopsy all that are indeterminate?

OBJECTIVE

The purpose of our study was to report the diagnostic yield of 58 consecutive imaging-guided biopsies of solid renal masses.

MATERIALS AND METHODS

We retrospectively reviewed all percutaneous renal biopsies of solid masses performed at our institution over 83 consecutive months from May 1998 to March 2005 through a query of our radiology department procedure database. Fifty-five CT and three sonographic biopsies were performed at our institution during this time. A solid renal mass was documented prior to biopsy by contrast-enhanced CT (n = 48), gadolinium-enhanced MRI (n = 6), or sonography (solid noncystic masses, n = 4). The average maximal mass diameter was 3.1 cm (range, 1.0-11.0 cm). Forty-seven (81%) of the 58 biopsies were performed immediately before percutaneous ablation. Forty-four (76%) of the biopsies were performed using a coaxial technique with side-cutting automated biopsy needles (16-20 gauge), and 14 (24%) were fineneedle aspirations with a Franseen needle (20 gauge) using a tandem technique. In 19 cases, immunohistochemistry or histochemistry (Hale colloidal iron stain) was used to establish or confirm the diagnosis. Medical records and radiology and pathology reports were reviewed for all patients.

RESULTS

An adequate sample size was obtained in 55 (95%) of 58 renal masses and led to a definitive diagnosis in 52 (90%) of the 58. Renal cell carcinoma accounted for 36 (69%) of 52 diagnostic biopsies. The diagnosis of a benign lesion was made in 14 (27%) of 52 biopsies. Lymphoma (1/58) and metastatic disease (1/58) accounted for the remaining two diagnostic biopsies. Three biopsy samples obtained inadequate sample volumes, and an additional three samples were thought to have adequate sample volume but were not diagnostic. A single false-negative biopsy result was identified after growth was seen on follow-up imaging and subsequent nephrectomy revealed renal cell carcinoma.

CONCLUSION

Imaging-guided biopsy of a solid enhancing renal mass was diagnostic in 52 (90%) of 58 consecutive biopsies. The diagnosis of a benign lesion was made in 27% of diagnostic biopsies. Because of the advances in biopsy and histology techniques, the role of imaging-guided biopsy should be reconsidered.

Nanomolecular histopathology for renal tumor classification

Renal tumors are classified into histopathologic subtypes based on light microscopy. Classification is important because subtypes have distinct genetic abnormalities and clinical behavior, yet is difficult because many cases have heterogeneous morphology. Thus, several molecular assays have been developed for tumor classification. Immunohistochemistry (IHC) permits correlation of molecular data with tissue morphology, but is difficult to quantify or perform in multiplex. Quantitative RT-PCR and gene expression microarrays are more quantitative, but lose morphologic information. We hypothesize that direct integration of histopathology with nanomolecular expression profiling will provide sensitive and specific data for renal tumor classification. Thus, we are developing novel IHC assays using antibodies conjugated to nanoparticle tags with surface-enhanced Raman scattering properties (SERS). Our preliminary data suggests that SERS-IHC can be performed using standard microscopic equipment, with potential for sensitive, quantitative multiplex assays on fixed tissues.

Improvement of SVM Algorithm for Microarray Analysis Using Intelligent Parameter Selection

Identification of genetic markers is a crucial step in the diagnosis, prognosis, and treatment of disease. This paper focuses on the application of a supervised classification technique, support vector machines (SVM), to high dimensional microarrays for marker identification. A case study of renal cell carcinoma (RCC) is used here to demonstrate and test the ability of SVMs to identify real biological markers. SVMs are known to be suitable for high dimensional microarray data and are able to classify non-linear relationships in the data through the use of kernel functions specific to the datasets. This paper compares multiple SVM kernel functions, both linear and nonlinear, to determine which form is best suited for a particular dataset. Additionally, each SVM is tested across a range of parameters and normalization schemes to further identify a specific optimal classifier. Empirical results are then used to determine the optimum parameters for the SVM to efficiently find biologically important predictive markers for differentiation between RCC subtypes for the purpose of diagnosis and prognosis.

Percutaneous cryoablation of renal cell carcinoma guided by horizontal open magnetic resonance imaging

BACKGROUND

Cryoablation is a treatment option for some patients with small exophytic lesions of the kidney. The purpose of this study is to determine the feasibility, safety, and intermediate-term treatment outcome of percutaneous cryoablation of renal cell carcinoma guided by horizontal open magnetic resonance imaging (MRI).

METHODS

We prospectively used cryoablation to treat 13 patients with radiographically confirmed enhancing small, solid renal tumors (< or =4.8 cm). An argon gas-based cryoablation system was used. One to four cryoprobes with 2 or 3-mm diameters were placed percutaneously into the tumor under local anaesthesia and MRI guidance. Ice ball dimensions were monitored by 2-D MR images. Double freeze-thaw cycles were conducted throughout the procedure. After successful cryoablation, patients were followed on a regular basis to evaluate the treatment's clinical outcome.

RESULTS

Median follow up from time of procedure is 35 months (range, 28-42). In all cases the entire procedure was accomplished without significant morbidity or complications. A mild retroperitoneal hematoma, which subsided spontaneously, was noted in one patient. Follow-up dynamic computed tomography (CT) at 3 months after operation confirmed the absence of enhancement in resolved tumor masses for 11 of 13 cases. None of these 11 patients had clinical evidence of recurrent disease at last follow up. The remaining two patients had lesions with some enhanced areas. Subsequent partial nephrectomy histologically confirmed the presence of vital tumor in, respectively, the center and the periphery of the residual masses. One of these patients developed multiple lung and ipsilateral adrenal metastases 13 months after surgical resection.

CONCLUSIONS

Percutaneous cryoablation of small renal cell carcinomas under horizontal open MRI guidance appears to be safe and feasible. An intermediate-term follow up continues to demonstrate efficacy in most patients; however, a few patients experience incomplete ablation with risk of treatment failure. The ideal candidates for this procedure still need to be determined in longer follow up with diligent observation.

Renal Masses in the Adult Patient: The Role of Percutaneous Biopsy

Although percutaneous renal mass biopsy with cross-sectional imaging guidance has long been considered to be safe and accurate, there have been recent advances in imaging, interventional, and cytologic techniques that have increased the role of percutaneous biopsy in the diagnosis of renal masses. Today, biopsy plays a fundamental role in the care of patients with a renal mass. Biopsy results are used to confirm the diagnosis of renal cancers, metastases, and infections, and there is increasing evidence to suggest that biopsy can help subtype and grade many primary renal cancers. Because a considerable fraction of small solid renal masses are benign and do not need treatment, there is an increasing need to diagnose them. Biopsy after a full imaging work-up can help prevent unnecessary and potentially morbid surgical and ablation procedures in a substantial number of patients. Although more data are needed to understand the overall accuracy of biopsy for the diagnosis of benign lesions, many can be diagnosed with the aid of biopsy findings. This article reviews reported experience with percutaneous renal mass biopsy, discusses the technical factors that contribute to results, and details seven specific clinical settings that should prompt the clinician to consider percutaneous biopsy when encountering a renal mass.

Renal cell carcinoma: The influence of new diagnostic imaging techniques on the size and stage of tumors diagnosed over the past 26 years

We have analyzed data collected over a 26-year period for influences of new diagnostic imaging techniques (ultrasound, computed tomography, and magnetic resonance imaging) on the size, stage, and other parameters of renal cell carcinomas at the time of first diagnosis. We reviewed retrospectively the records of 203 patients who underwent operations at our institutions from 1973 to 1999. All the patients suffered from renal cell carcinoma. With this study we attempted to answer four questions regarding changes over this time span: (1) have new imaging techniques lead to a reduction in the median diameter of the tumor upon first diagnosis, (2) has the tumor stage decreased due to earlier diagnosis, (3) is there any correlation between tumor size and tumor stage, and (4) are the patient's early diagnoses at a younger age? Other parameters such as infiltration of the renal pelvis and the cell type were also examined. The tumor size and stage at the time of diagnosis and treatment are positively correlated, and both decrease significantly over the time span examined. There is also a strong association between tumor size and infiltration of the renal pelvis. The median age of the patients did not significantly change over time. The wider use of improved imaging techniques has significantly changed the clinical appearance of the renal cell carcinoma. The question is whether these techniques have also affected the prognosis of the disease.

MRI-guided percutaneous cryoablation of renal tumors: use of external manual displacement of adjacent bowel loops

PURPOSE

We sought to investigate retrospectively the safety and effectiveness of using external hand compression to displace adjacent bowel loops during MRI-guided percutaneous cryoablation of renal tumors.

MATERIALS AND METHODS

Fourteen patients (six women, eight men; mean age: 72 years) with 15 renal tumors (mean diameter: 2.4 cm; range: 1.4-4.6 cm) adjacent to bowel were treated with MRI-guided percutaneous cryoablation during which bowel was displaced manually. Bowel loop of concern was ascending colon (n=5), descending colon (n=8), descending colon and small bowel (n=1), ascending colon and small bowel (n=1). To analyze effectiveness of the maneuver, mean distance between tumor margin and bowel before and after the maneuver were compared and analyzed using paired Student's t-test. Minimum distance between iceball edge and adjacent bowel with external manual displacement during freezing was also measured. Safety was assessed by analyzing post-procedural MR imaging for adjacent bowel wall thickening and focal fluid collections as well as patients' clinical and imaging follow-up.

RESULTS

Mean distance between tumor margin and closest adjacent bowel increased from 0.8 cm (range: 0-2 cm) before external manual compression to 2.6 cm (range: 1.6-4.1 cm) with manual displacement (p<0.01). Mean minimum distance between iceball edge and closest adjacent bowel during the procedures was 1.6 cm (range: 0.5-3.5 cm). No evidence of bowel injury was encountered. Twelve of 15 tumors had follow-up (mean: 10 months) that showed no tumor recurrence.

CONCLUSION

MRI-guided percutaneous cryoablation of renal tumors adjacent to bowel can be done safely and effectively using external hand compression to displace bowel loops.

Prognostic implication of capsular invasion without perinephric fat infiltration in localized renal cell carcinoma

OBJECTIVES

To analyze the prognostic value of capsular invasion without perinephric fat infiltration in patients with localized renal cell carcinoma (RCC) Stage pT1-pT2N0M0.

METHODS

A total of 288 patients with RCC (conventional type) confined to the kidney (pT1-pT2N0M0) who underwent radical nephrectomy from January 1993 to November 2004 at our institution were included in our study. The disease of all patients was staged according to the 2002 TNM classification system. Pathologic findings, including T stage, nuclear grade, and capsular invasion, were retrospectively reviewed. Disease-specific survival was compared according to the capsular invasion.

RESULTS

Tumor invasion of the renal capsule was identified in 108 (37.5%) of the 288 patients. Of the 230 patients with Stage pT1, 78 (33.9%) had lesions invading the renal capsule and 30 (51.7%) of 58 patients with Stage pT2 had capsular invasion. Involvement of the renal capsule was associated with a worse pT stage (P = 0.015). The 5-year disease-specific survival rate for patients with no capsular invasion versus with capsular invasion was 91.8% versus 84.3%, respectively (P = 0.132). For patients with pT1 tumors, the 5-year disease-specific survival rate was 95.6% for patients without capsular invasion and 92.6% for those with capsular invasion (P = 0.299). For patients with pT2 tumors, the 5-year disease-specific survival rate was 90.5% for patients without capsular invasion and 73.8% for those with capsular invasion (P = 0.031).

CONCLUSIONS

Renal capsular invasion is associated with a worse stage in localized RCC. Patients with Stage pT2 RCC and capsular invasion appear to have a worse prognosis than those with equivalently staged RCC without capsular invasion.

Radiofrequency ablation of a central renal tumor: protection of the collecting system with a retrograde cold dextrose pyeloperfusion technique

Renal radiofrequency (RF) ablation therapy is a safe and effective therapy for small renal cell carcinoma. Although the risk of complications is low, the potential for ureteral or calyceal injury does increase in the case of a centrally located lesion. A retrograde cold dextrose pyeloperfusion technique was designed to protect the collecting system in a patient who underwent percutaneous RF ablation of a central tumor of the left kidney.

Expression of COX-2 in normal and pyelonephritic kidney, renal intraepithelial neoplasia, and renal cell carcinoma

OBJECTIVES

The role of inflammation in carcinogenesis is unknown. To determine the relationship between cyclooxygenase 2 (COX-2) expression, inflammation, and carcinogenesis in human renal cell carcinoma (RCC), we looked for COX-2 expression in normal and pyelonephritic kidney, renal intratubular neoplasia (RIN), and RCC tissues.

METHODS

COX-2 expression was assessed immunohistochemically in tissues obtained from 20 pyelonephritic kidneys, 16 normal kidneys, 19 RIN, and 75 RCC cases.

RESULTS

COX-2 expression was found to be positive in 64% of RCCs. It was positive in 13 chronic pyelonephritic (65%), 9 normal (56%), and 15 RIN (79%) cases. COX-2 expression was significantly higher in RCC and RIN than the normal and pyelonephritic cases (p<0.001 and p<0.001, respectively). No statistically significant difference was noted between RCC and RIN cases.

CONCLUSIONS

Although the function of COX-2 in tumor development has not been exactly elucidated, the increased expression of COX-2 in RIN and RCC might be a factor that may play a role in the development of RIN or progression to RCC, which warrants further research.

Molecular classification of renal tumors by gene expression profiling

Renal tumor classification is important because histopathological subtypes are associated with distinct clinical behavior. However, diagnosis is difficult because tumor subtypes have overlapping microscopic characteristics. Therefore, ancillary methods are needed to optimize classification. We used oligonucleotide microarrays to analyze 31 adult renal tumors, including clear cell renal cell carcinoma (RCC), papillary RCC, chromophobe RCC, oncocytoma, and angiomyolipoma. Expression profiles correlated with histopathology; unsupervised algorithms clustered 30 of 31 tumors according to appropriate diagnostic subtypes while supervised analyses identified significant, subtype-specific expression markers. Clear cell RCC overexpressed proximal nephron, angiogenic, and immune response genes, chromophobe RCC oncocytoma overexpressed distal nephron and oxidative phosphorylation genes, papillary RCC overexpressed serine protease inhibitors, and extracellular matrix products, and angiomyolipoma overexpressed muscle developmental, lipid biosynthetic, melanocytic, and distinct angiogenic factors. Quantitative reverse transcriptase-polymerase chain reaction and immunohistochemistry of formalin-fixed renal tumors confirmed overexpression of proximal nephron markers (megalin/low-density lipoprotein-related protein 2, alpha-methylacyl CoA racemase) in clear cell and papillary RCC and distal nephron markers (beta-defensin 1, claudin 7) in chromophobe RCC/oncocytoma. In summary, renal tumor subtypes were classified by distinct gene expression profiles, illustrating tumor pathobiology and translating into novel molecular bioassays using fixed tissue.

Percutaneous radiofrequency ablation of renal cell carcinoma

BACKGROUND

Preliminary data regarding the use of percutaneous radiofrequency ablation (RFA) for the treatment of renal cell carcinoma (RCC) are encouraging, and show the technique to be associated with minimal morbidity. Thus, the current study was designed to evaluate the clinical applications, treatment efficacy, and complications of percutaneous RFA in RCC.

METHODS

From February 2003 to February 2004, 12 consecutive patients with histopathologically proven RCC underwent imaging-guided percutaneous RFA. The mean age of the patients (8 men and 4 women) was 76 years (range, 56-87 years), and mean tumor diameter was 3.7 cm (range, 2.2-8.0 cm). The efficacy of RFA was evaluated with contrast-enhanced, dynamic computed tomography (CT) performed 1 month after treatment, and then every 3 months. A Radionics device with an internally cooled electrode was used in 7 patients, and a radiofrequency interstitial tissue ablation (RITA) device with an expandable needle electrode was used in 5. Complete necrosis was defined as a lack of contrast enhancement in the treated region on follow-up CT studies.

RESULTS

Overall, 16 sessions of RFA were performed for 12 solitary renal tumors in 12 patients: 8 patients underwent a single RFA session, whereas 4 had 2 sessions. Dynamic CT after RFA showed complete necrosis in 9 of 12 tumors. In 3 patients with tumors of 4.5-8.0 cm in diameter, enhancement of residual tissue was observed after RFA treatment, thus indicating residual tumor. Complete tumor necrosis was seen in all 5 tumors (100%) of diameter < or = 3.0 cm; 3 of 4 tumors (75%) of diameter 3.1-5.0 cm; and 1 of 3 tumors (33%) of diameter > 5.0 cm. A big subcapsular hematoma, which was found in 1 patient after RFA, resolved completely within 10 months without treatment; no serious complications occurred in the other 11 patients.

CONCLUSION

Percutaneous RFA is effective in the treatment of RCC. It is most successful for tumors not larger than 3 cm in diameter, and has a satisfactory success rate in tumors of 3-5 cm in diameter. The rate of serious complications of RFA is low. Further studies are necessary to determine the long-term efficacy of RFA in RCC.

The prevalence of renal cell carcinoma diagnosed at autopsy

OBJECTIVE

To compare the rate of renal cell carcinoma (RCC) detected only at autopsy, from two periods, to determine if the apparent recent increase in RCC in the USA is a true increase or mainly a result of improved imaging techniques, as a true increase in the clinical incidence of RCC should not affect the number of previously undiscovered RCC found only at autopsy.

PATIENTS AND METHODS

We identified all individuals who underwent autopsy in two periods, 1955-60 (3307) and 1991-2001 (2938), and who were identified with renal tumour either before or after death. Information was obtained on age, sex, histological type and size of tumour, and whether the tumour was identified before or only after death. All cases of RCC detected at autopsy were reviewed for this analysis by one pathologist (L.D.).

RESULTS

Between 1955-60 and 1991-2001 there was a 55% reduction in the mean annual number of autopsies. The proportion of malignant renal masses (RCC) did not change significantly (35.4% to 32.8%). The rate of previously unsuspected RCC detected only at autopsy did not change significantly (0.91 vs 0.72 per 100 autopsies).

CONCLUSION

The number of renal masses, both benign and malignant, discovered only at autopsy is declining, possibly because of better detection before death. However, the rate of occult kidney cancer per 100 autopsies did not change significantly between the two periods, suggesting a true increase in the frequency of clinically detected kidney cancer.

Cyclooxygenase-2 expression and relationship to tumour progression in human renal cell carcinoma

AIMS

Cyclooxygenase (COX), which catalyses the synthesis of prostaglandins from arachidonic acid, has two isoforms; COX-1 and COX-2. There is ample evidence to suggest an important role for COX-2 in cancer. The aim of this study was to evaluate the clinical significance of COX-2 expression and its localization in the development and progression of human renal cell carcinoma (RCC).

METHODS AND RESULTS

The expression and localization of COX-2 were evaluated in human RCC tissues from 75 patients by immunohistochemistry. Immunoreactive COX-2 protein was observed in all cases of RCC, and the levels of COX-2 expression were correlated with tumour grade and pathological stage. Expression of COX-2 was higher in the granular cell subtype than in the clear cell subtype of RCC. Immunoelectron microscopy revealed that COX-2 was expressed in the nuclear membrane, rough endoplasmic reticulum, Golgi complex and mitochondrial membrane of RCC cells.

CONCLUSION

COX-2 overexpression within these intracellular organelles in RCC may be associated with renal cell carcinogenesis and COX-2 may be a useful biomarker in RCC.

Percutaneous CT-guided radiofrequency ablation of renal neoplasms: factors influencing success

OBJECTIVE

The objective of our study was to evaluate the success rate for radiofrequency ablation of renal tumors and to determine the risk of serious complications.

CONCLUSION

No serious complications occurred after 27 CT-guided radiofrequency ablation sessions in 22 patients. In total, no residual tumor was detected on follow-up contrast-enhanced CT or MRI 1-35 months (mean, 7 months) after final tumor ablation in 20 (91%) of 22 patients. Two patients with residual viable tumor deferred further treatment. Complete tumor ablation was achieved after a single treatment session in 83% of patients, and in 8% of patients after subsequent ablation sessions. Size was the major determinant for achieving tumor eradication with a single session of ablation, with all 11 tumors 3 cm or smaller being completely ablated after one session. Tumor location, histology, and the presence of renal disease did not correlate with treatment success. Contrast-enhanced CT performed immediately after ablation is reliable to exclude residual viable tumor. CT-guided radiofrequency ablation of renal tumors is safe and has a high rate of success in the treatment of small renal tumors, with no evidence of recurrence at midterm follow-up of treated patients.

Evaluation of patients referred for percutaneous ablation of renal tumors: importance of a preprocedural diagnosis

OBJECTIVE

Percutaneous ablation of renal cell carcinoma has the potential to be as effective as partial nephrectomy. Because the entire tumor cannot be examined at pathology, diagnosis relies solely on imaging and percutaneous biopsy. Diagnoses of cancer have been rendered using imaging alone in some clinical trials of percutaneous ablation. If these trials inadvertently included benign masses, the efficacy of ablation was overestimated. Therefore, we sought to determine the prevalence of benign masses in a population of patients referred for percutaneous tumor ablation of presumed renal cell carcinoma.

SUBJECTS AND METHODS

Twenty-seven patients were referred by urologists for MRI-guided cryotherapy of suspected renal cell carcinoma. Renal masses ranged from 1.0 to 4.6 cm (mean, 2.2 cm) in diameter. The CT, MRI, and percutaneous biopsy findings were tabulated and compared with surgical and imaging follow-up.

RESULTS

Ten patients (37%) had a benign renal mass, including three angiomyolipomas, that had no evidence of fat on CT or MRI. Three masses were proven benign by biopsy, three by imaging, and four by a combination of biopsy and imaging. The masses in the remaining 17 patients were ablated. Biopsy revealed malignant cells in 10, suspicious cells in four, and atypical cells in two; one was nondiagnostic.

CONCLUSION

A substantial percentage of patients referred for percutaneous ablation of renal tumors had benign masses. If CT or MRI alone cannot be used to diagnose a benign entity, patients should undergo a biopsy before the treatment session.

Small renal cell carcinomas: correlation of size with tumor stage, nuclear grade, and histologic subtype

OBJECTIVE

Our goal was to correlate the size of renal cell carcinoma with tumor stage, nuclear grade, and histologic subtype in patients treated using partial or radical nephrectomy.

MATERIALS AND METHODS

We retrospectively reviewed 213 consecutive renal cell carcinomas resected at our institution from 1995 through 1999. Three groups of lesions stratified by size (< or = 3 cm, > 3-5 cm, > 5 cm) were compared with regard to pathologic findings. Statistical significance was assessed using Fisher's exact test.

RESULTS

Of 50 lesions 3 cm or smaller, 19 (38%) had extension outside the renal capsule (T3 or T4) and 14 (28%) were a high nuclear grade (Fuhrman grade 3 or 4). Lesions 3 cm or smaller and those greater than 3 cm to 5 cm did not differ statistically with regard to T stage or nuclear grade. Lesions larger than 5 cm showed a statistically higher T stage (p < 0.001) and nuclear grade (p = 0.001) than the other smaller lesions. More non-clear cell tumors were found in the two groups of smaller lesions (p = 0.105) but without statistical significance. The majority (58%) of the tumors were asymptomatic and had been detected incidentally on cross-sectional imaging. Lesions larger than 5 cm were significantly more likely to be symptomatic (p < 0.001). Seventy-nine percent of the tumors 3 cm or smaller were incidental, and these lesions did not differ significantly from the symptomatic lesions with regard to stage, grade, or histology.

CONCLUSION

In our study population, renal cell carcinomas up to 3 cm, including asymptomatic lesions, showed a significant incidence of high nuclear grade and tumor extension beyond the renal capsule; these findings support aggressive management of small lesions. Symptomatic status was not an adequate discriminator to guide management. A longitudinal study is necessary to further evaluate the efficacy of current patterns of therapy.

The natural history of incidentally detected small renal masses

BACKGROUND

The incidence of renal cell carcinoma (RCC) is increasing, largely due to the widespread use of cross-sectional imaging. Most renal tumors are detected incidentally as small, asymptomatic masses. To study their natural history, the authors prospectively followed a series of patients with this type of lesion who were unsuited for or refused surgery.

METHODS

Twenty-nine patients with 32 masses that measured < 4 cm in greatest dimension (25 solid masses and 7 complex cystic masses) were studied. The primary outcome was tumor size, which was calculated as volume over time. All patients were followed with serial abdominal imaging, and each mass had at least three follow-up measurements. The median follow-up was 27.9 months (range, 5.3-143.0 months).

RESULTS

Overall, the average growth rate did not differ statistically from zero growth (P = 0.09; 95% confidence interval, - 0.005-0.2 cm per year) and was not associated with either initial size (P = 0.28) or mass type (P = 0.41). Seven masses (22%) reached 4 cm in greatest dimension after 12-85 months of follow-up. Eight masses (25%) doubled their volumes within 12 months. Overall, 11 masses (34%) fulfilled 1 of these 2 criteria of rapid growth. Nine tumors were removed surgically after an average of 3.1 years of follow-up because it was believed that they were growing fast. No patient had disease progression.

CONCLUSIONS

Approximately one-third of small renal masses that are presumed RCCs grow if they are managed conservatively and are followed with serial imaging. The growth rate is slow or undetectable in the majority of patients. These observations raise the possibility of a period of initial observation in selected patients, particularly the elderly or infirm.

[Renal cell carcinoma in adults less than 40 years of age: a particular cancer? Incidence, outcome and review of the literature]

OBJECTIVE

To study the incidence, clinical presentation, pathological prognostic factors and disease outcome of RCC in young adults less than 40-years-old.

MATERIAL AND METHODS

The notes of 400 patients treated by radical nephrectomy for RCC suspicion, between January 1984 and december 1999 were reviewed. Twenty-nine patients (7.25%) were under 40.

RESULTS

The most common histological cell type was clear cell carcinoma, found in 20 patients (69%). At a median follow-up of 80 months, 20 patients (69%) were disease free and 9 (31%) died of the disease. When comparing patients less than 40 years vs older than 40 years, we found significant differences in histology type (clear cell carcinoma 69% vs 91%; P = 0.0001), and tumor stage at presentation (pT2 = 34.5% vs 17.3%; P = 0.04) (pT3 = 20.7% vs. 42%; P = 0.03). Disease free survival was not significantly different between the 2 groups (69% vs 65.7%; Log rank test P = 0.4).

CONCLUSION

Although rare, RCC in young adults seems to follow a course similar to the disease seen in older patients. Stage at presentation was different between the 2 populations however survival was not affected by age.

Current staging of renal cell carcinoma

Most (>80%) cancers involving the kidney are renal cell carcinoma (RCC). One third of patients diagnosed with kidney cancer have evidence of metastatic disease at the time of diagnosis, and as many as half of patients treated for localized disease eventually relapse. As is true for any other malignancy, one must determine which tumor features, patient factors, and laboratory techniques will provide diagnostic and prognostic information for patients with RCC. This article focuses on the history and rationale of the current staging systems for RCC as well as the potential for improvements by the addition of other clinical, pathologic, and molecular prognostic markers.