Small renal masses: incidental diagnosis, clinical symptoms, and prognostic factors

Kidney Cancer Incidence among Non-Hispanic American Indian and Alaska Native Populations in the United States, 1999 to 2020

BACKGROUND

Non-Hispanic American Indian and Alaska Native (NH-AI/AN) people exhibit a disproportionate incidence of kidney cancer. Nationally aggregated data do not allow for a comprehensive description of regional disparities in kidney cancer incidence among NH-AI/AN communities. This study examined kidney cancer incidence rates and trends among NH-AI/AN compared with non-Hispanic White (NHW) populations by geographic region.

METHODS

Using the United States Cancer Statistics American Indian and Alaska Native (AI/AN) Incidence Analytic Database, age-adjusted incidence rates (per 100,000) of kidney cancers for NH-AI/AN and NHW people for the years 2011 to 2020 combined using surveillance, epidemiology, and end Results (SEER)∗stat software. Analyses were restricted to non-Hispanic individuals living in purchased/referred care delivery area (PRCDA) counties. Average annual percent changes (AAPCs) and trends (1999-2019) were estimated using Joinpoint regression analyses.

RESULTS

Rates of kidney cancer incidence were higher among NH-AI/AN compared with NHW persons in the United States overall and in five of six regions. Kidney cancer incidence rates also varied by region, sex, age, and stage of diagnosis. Between 1999 and 2019, trends in kidney cancer rates significantly increased among NH-AI/AN males (AAPC = 2.7%) and females (AAPC = 2.4%). The largest increases were observed for NH-AI/AN males and females aged less than 50 years and those diagnosed with localized-stage disease.

CONCLUSIONS

Study findings highlight growing disparities in kidney cancer incidence rates between NH-AI/AN and NHW populations.

IMPACT

Differences in geographic region, sex, and stage highlight the opportunities to decrease the prevalence of kidney cancer risk factors and improve access to preventive care.

The quantitative evaluation of contrast-enhanced ultrasound in the differentiation of small renal cell carcinoma subtypes and angiomyolipoma

Background

Contrast-enhanced ultrasound (CEUS) has been widely used for renal lesion diagnosis and differential diagnosis. However, qualitative analysis of CEUS is subject to examinations with low reproducibility. This study aims to investigate the diagnostic value of CEUS quantitative parameters in differentiating small renal cell carcinoma (RCC) subtypes and angiomyolipoma (AML).

Methods

A retrospective analysis was performed on 97 cases of a small renal mass undergoing a CEUS before a radical or partial nephrectomy procedure. A region of interest (ROI) was placed in the tumor's maximum enhanced region (ROI_max) as much as possible, and adjacent renal cortex (ROI_refer) was selected from normal renal tissue around a mass of the same depth. The time-intensity curve (TIC) was used to analyze the ROI_max and the ROI_refer of the tumors quantitatively. Then the parameters of the ROI_max and the ROI_refer, including the differences between the parameters of the ROI_max and the ROI_refer, were analyzed statistically.

Results

In RCC and clear cell renal cell carcinoma (ccRCC), the peak intensity (PI), slope (SL), area under the curve (AUC), area under the wash-in curve (AWI), area under the wash-out curve (AWO), time to peak intensity (TTP) and the mean transit time (MTT) were statistically significant between ROI_max and ROI_refer (all P=0.000). The △PI (△PI = PI_max - PI_refer), △SL (△SL = SL_max - SL_refer), △AUC (△AUC = AUC_max - AUC_refer), △AWI (△AWI = AWI_max - AWI_refer) and △AWO (△AWO = AWO_max - AWO_refer) of RCC were significantly higher than in AML (P=0.007, 0.000, 0.003, 0.048, 0.009, respectively), while the TTP (△TTP = TTP_max - TTP_refer) and △MTT (△MTT = MTT_max - MTT_refer) of RCC were significantly lower (both P=0.000). In comparison with papillary renal cell carcinoma (pRCC) and chromophobe renal cell carcinoma (chRCC), the △PI, △SL, △AUC and △AWO of ccRCC were all larger (all P<0.05). The sensitivity, specificity, and AUC of the combination of parameter difference for differentiating RCC from AML were 100%, 81.2%, and 0.965, respectively, and for differentiating ccRCC from pRCC and chRCC, 85.71%, 85.92% and 0.911, respectively.

Conclusions

CEUS quantitative parameters have value in differentiating small RCC from AML and distinguishing ccRCC from pRCC and chRCC.

A prospective observational study of the epidemiology and pathological profile of RCC in a South African referral centre

Background

There are global differences in the incidence, stage, prognosis, pathological profile and presentation of renal cell carcinoma (RCC). We review and describe the risk factors, pathological profile, stage and epidemiology of RCC in a South African centre. Prospective data were collected from all patients undergoing partial or radical nephrectomy for suspected RCC from July 2016 to March 2018.

Results

We collected data from 35 patients and excluded four patients after histological examination showed benign disease. The most common mode of presentation was incidental finding in 48%; with only one case presenting with the classical triad of abdominal mass, flank pain and macroscopic haematuria. The pathological profile of RCC cases included: clear cell 23 (74%), papillary type II 5 (16%), papillary mixed type I and II 1 (3%) and chromophobe 2 (7%). The pathological stage of the patients varied, from pT1a to pT3b. The median stage of presentation was pT1b. There was a trend towards a more advanced stage with the presence of obesity, female gender, smoking and hypertension.

Conclusion

The pathological profile and presenting symptoms in our population mimics that seen in Europe and the USA, with the exception of an increased prevalence of papillary type II RCC. The stage and presenting symptoms differ from that seen in other African studies, whilst our population followed the trend of younger presentation seen elsewhere in Africa.

Prognostic Effect of Comorbid Disease and Immune Gene Expression on Mortality in Kidney Cancer-A Population Based Study

The effect of comorbidities and the immune profiles of the kidney cancer microenvironment play a major role in patients’ prognosis and survival. Using the National Health Insurance Research Database (Taiwan), we identified patients aged >20 years with a first diagnosis of kidney cancer between 2005 and 2014. Differences in demographic characteristics and comorbidities were examined using the Pearson chi-squared test or the t test. The Cox regression model was used to construct the nomogram. RNA-seq data were applied from The Cancer Genome Atlas database, and correlations between immune metagenes and clinical characteristics were determined using a linear regression model. In this nationwide cohort study, including 5090 patients with kidney cancer, predictors in our prediction models included age, sex, chronic kidney disease, dialysis requirements, renal stones, cerebrovascular disease, and metastasis tumor. In the tumor tissue profiles, significant positive correlations between immune metagenes and clinical stage or overall survival were observed among Natural Killer (NK) cells (CD56−), CD4+ T-helper 2 (Th2) cells, and activated Dendritic Cell (aDC). A negative correlation was observed between expression level of Dendritic Cell (DC) and overall survival. Patients with kidney cancer exhibit high prevalence of comorbid disease, especially in older patients. Comorbid disease types exert unique effects, and a particular comorbidity can affect cancer mortality. Moreover, the expression of immune metagenes can be utilized as potentialbiomarkers especially for further study of molecular mechanisms as well as microenvironments in kidney cancer.

T1a renal cell carcinoma on unenhanced CT: analysis of detectability and imaging features

Background

Increasing use of unenhanced computed tomography (CT) has been associated with the increasing incidental detection of renal cell carcinoma (RCC) at an earlier stage.

Purpose

To evaluate the characteristics in detecting and differentiating T1a RCCs on unenhanced CT.

Material and Methods

We retrospectively reviewed 68 patients with 68 T1a RCCs and 39 benign regions. Two radiologists interpreted the images on unenhanced axial CT and performed a blinded and independent review of T1a RCCs. The readers evaluated the presence of RCC and differentiated the detected lesions.

Results

The consensus of two readers detected 53 (78%) RCCs. Of the 53 detected RCCs, 42 (62%) RCCs were correctly diagnosed and 11 (16%) masses were misdiagnosed as benign. Of the 39 benign regions, 29 (74%) cysts were diagnosed correctly, but 10 (26%) cysts were misdiagnosed as malignant. The following values of the radiologists were obtained by consensus: sensitivity = 61.8% (42/68); specificity = 74.4% (29/39); positive predictive value = 80.8% (42/52); negative predictive value = 55.0% (29/55); accuracy = 66.4% (71/107). The receiver operating characteristic curve of consensus was 0.754. Inter-observer correlation was κ = 0.849. There was a significant difference in tumor size (P = 0.019) and the contour type of tumor (P = 0.0207) between correctly diagnosed RCCs and not correctly diagnosed RCCs.

Conclusion

Our findings showed that tumor size and contour type could affect the detection and differentiation of T1a RCC on unenhanced CT. To detect and differentiate T1a RCC on unenhanced CT is difficult. However, the findings from this study may help detection of RCCs on unenhanced CT.

Outcomes of Nephron Sparing in a Specialist Cancer Hospital of a Developing Country

Introduction

Nephron-sparing surgery in the form of partial nephrectomy (PN) is currently considered the standard treatment for relatively small localized renal cell tumors.

Objectives

This study aimed to determine outcomes of PN regarding complications, recurrence, and survival rates at Shaukat Khanum Memorial Cancer Hospital and Research Centre, Lahore, Pakistan.

Methods

We assessed the data of patients older than 18 years undergoing PN from January 2010 to June 2017 who met our inclusion criteria. Data were analyzed using IBM SPSS Statistics for Windows, Version 20.0 (IBM Corp., Armonk, NY).

Results

A total of 35 patients were studied, with a male to female ratio of 2.5:1 with median age of 50 years. The median hospital stay was four days (range: 3-7), and the median RENAL (radius, exophytic/endophytic properties, nearness of tumor to the collecting system or sinus in millimeters, anterior/posterior location relative to polar lines) Score was five (range: 4-10). The most common pathological tumor stage was T1 (94%), and the median size was 3.5 cm. On histopathology, clear-cell carcinoma was the most common tumor (incidence, 71%). The median Fuhrman’s grade was two. On final histopathology, four patients had positive margins. Among them, two patients showed a progressive deterioration in renal functions and were found to have residual disease six months later. Only one patient developed metastasis in the lung. Wound infection was observed in one patient while another had wound dehiscence. Urine leakage was noted in two patients. The median follow-up duration was 18 months (range: 3-84). Mean cancer-free survival was 78.6 months, and overall survival was 79.2 months. The projected three-year and five-year disease-free and overall survival was 96% and 94%, respectively.

Conclusion

PN is a viable option with excellent outcomes regarding the complication profile, recurrence-free, and overall survival in patients with relatively small localized renal tumors.

Differences in Renal Tumor Size Measurements for Computed Tomography Versus Magnetic Resonance Imaging: Implications for Patients on Active Surveillance

PURPOSE

To evaluate and compare the accuracy of computed tomography (CT) and magnetic resonance imaging (MRI) in predicting the final pathologic tumor size of partial nephrectomy specimens.

MATERIALS AND METHODS

We analyzed a multi-institutional database of 807 patients who underwent robotic partial nephrectomy for a cT1a renal mass from 2006 to 2016. Patients who had a solitary tumor with complete data on the baseline imaging modality and the tumor size (baseline and pathologic) (n = 349) were included for analysis. Baseline tumor size evaluated by both imaging modalities, in addition to the difference between the measurements and final pathologic tumor size (cm) measurements, was compared between patients who received a baseline CT (n = 276, 79.1%) and those who received an MRI (n = 73, 20.9%).

RESULTS

There were no statistically significant differences between any baseline characteristics and receipt of a CT versus MRI. In multivariable analysis adjusting for confounders, there was no significant difference in the baseline tumor size between patients receiving an MRI and those receiving a CT (2.3 versus 2.6 cm; β = -0.13; 95% confidence interval [CI] = -0.33 to 0.07; P = .208). Tumor size on imaging was smaller from final pathology by 0.43 cm on average (P = .002). Measurement error for the measured baseline versus actual pathologic tumor size did not significantly differ for patients receiving an MRI versus those receiving a CT (0.38 versus 0.44 cm; β = -0.06; 95% CI = -0.16 to 0.04; P = .232).

CONCLUSION

Baseline renal tumor size measurements were not significantly different for CT scan and MRI. Choice of imaging modality can be based on doctor and patient preference, including cost and exposure to radiation.

Renal cavernous hemangioma: robot-assisted partial nephrectomy with selective warm ischemia. Case report and review of the literature

Renal hemangioma is a relatively rare benign tumor with a wide range of clinical and radiological presentation, not easy to differentiate preoperatively from a renal cancer. Due to its benign nature complete surgical resection is the recommended therapy and is considered curative. A 73-year old male patient followed-up for a lung carcinoma and a chronic renal failure underwent a CT scan showing a 35-mm mass of the inferior pole of the left kidney. The patient underwent robot-assisted partial nephrectomy with left inferior pole selective warm ischemia. The outcome was favorable and no repercussions on the renal reserve were observed postoperatively. Histopathological characteristics of the surgical specimen were consistent with renal cavernous hemangioma. A robot-assisted operation allows the fine dissection required to carry out a bloodless nephron-sparing surgery without a complete warm ischemia. The use of robot could be noteworthy for nephron-sparing surgery in cases of concomitant chronic renal failure.

Comparison of utility of tumor size and apparent diffusion coefficient for differentiation of low- and high-grade clear-cell renal cell carcinoma

BACKGROUND

There is a significant correlation between tumor size and tumor grade for clear-cell renal cell carcinoma (RCC) in pathology. Thus, apparent diffusion coefficient (ADC) of clear-cell RCC might be influenced by tumor size.

PURPOSE

To compare the utility of tumor size and ADC for distinguishing low-grade from high-grade clear-cell RCC.

MATERIAL AND METHODS

Forty-nine patients undergoing preoperative magnetic resonance imaging were retrospectively assessed. ADC values were calculated using b-value combinations of 0 and 800 s/mm(2) at 1.5 T. Two radiologists in consensus measured ADC values via small region of interest (ROI) (mean ROI area, 88.8 mm(2); range, 80-108 mm(2)) placement on an area of solid tumor on a single slice. Maximum tumor diameter was measured at the maximum tumor area. A single pathologist reviewed all pathological slides to determine the nuclear grade according to the Fuhrman classification. The utility of ADC, tumor size, and ADC/size ratio for distinguishing low-grade from high-grade tumors was assessed. Receiver-operating characteristic (ROC) analysis and regression analysis of the each index were performed. The correlation between ADC and tumor size was also investigated.

RESULTS

The 49 clear-cell RCC included 34 low-grade and 15 high-grade tumors. The differences of ADC, tumor size, and ADC/size ratio between high-grade and low-grade tumors were statistically significant (P <0.05). The area under the ROC curve of ADC, tumor size, and ADC/size ratio were 0.802, 0.763, and 0.804 respectively. However, using regression analysis, only ADC (P <0.05) was statistically significant index as independent risk factors for high-grade clear-cell RCC. Moreover, weak significant correlation was observed between tumor size and ADC (R(2) = 0.3865, P <0.01).

CONCLUSION

There was a weak significant correlation between tumor size and ADC value of clear-cell RCC. Using ROC and regression analysis, ADC was statistically significant index for distinguishing low-grade from high-grade clear-cell RCC more than tumor size and ADC/size ratio.

Radio-frequency ablation helps preserve nephrons in salvage of failed microwave ablation for a renal cancer in a solitary kidney

Recurrent tumors after renal ablative therapy present a challenge for clinicians. New ablative modalities, including microwave ablation (MWA), have very limited experience in methods of retreating ablation failures. Additionally, in MWA, no long-term outcomes have been reported. In patients having local tumor recurrence, options for surveillance or surgical salvage must be assessed. We present a case to help assess radio-frequency ablation (RFA) for salvage of failed MWA. We report a 63-year-old male with a 4.33-cm renal mass in a solitary kidney undergoing laparoscopic MWA with simultaneous peripheral fiber-optic thermometry (Lumasense, Santa Clara, CA, USA) as primary treatment. Follow-up contrast-enhanced computed tomography (CT) scan was performed at 1 and 4.3 months post-op with failure occurring at 4.3 months as evidenced by persistent enhancement. Subsequently, a laparoscopic RFA (LRFA) with simultaneous peripheral fiber-optic thermometry was performed as salvage therapy. Clinical and radiological follow-up with a contrast-enhanced CT scan at 1 and 11 months post-RFA showed no evidence of disease or enhancement. Creatinine values pre-MWA, post-MWA, and post-RFA were 1.01, 1.14, and 1.17 mg/ml, respectively. This represents a 15% decrease in estimated glomerular filtration rate (eGFR) (79 to 67 ml/min) post-MWA and no change in eGFR post-RFA. Local kidney tumor recurrence often requires additional therapy and a careful decisionmaking process. It is desirable not only to preserve kidney function in patients with a solitary kidney or chronic renal insufficiency, but also to achieve cancer control. We show the feasibility of RFA for salvage treatment of local recurrence of a T1b tumor in a solitary kidney post-MWA.

Expression of drug targets in primary and matched metastatic renal cell carcinoma tumors

BACKGROUND

Targeted therapies in renal cell carcinoma can have different effects on primary and metastatic tumors. To pave the way for predictive biomarker development, we assessed differences in expression of targets of currently approved drugs in matched primary and metastatic specimens from 34 patients.

METHODS

Four cores from each site were embedded in tissue microarray blocks. Expression of B-Raf, C-Raf, cKIT, FGF-R1, HIF-2α, mTOR, PDGF-Rβ, VEGF-R1, VEGF-R2, VEGF-R3, VEGF, VEGF-B, VEGF-C, VEGF-D, MEK1, and ERK1/2 was studied using a quantitative immunofluorescence method.

RESULTS

No significant differences were observed in global expression levels in primary and metastatic renal cell carcinoma tumors, with the exception of MEK, which had higher expression in metastatic than primary specimens. Similarly, more ki67 positive cells were seen in metastatic specimens. Correlations between marker expression in primary and metastatic specimens were variable, with the lowest correlation seen for FGF-R1 and VEGF-D. There were no significant differences in the degree of heterogeneity in primary versus metastatic tumors.

CONCLUSIONS

Expression of most of the studied markers was similar in primary and metastatic renal cell carcinoma tumors, suggesting that predictive biomarker testing for these markers can be conducted on either the primary or metastatic tumors for most markers.

Spontaneous regression of biopsy proven primary renal cell carcinoma: A case study

Spontaneous regression of renal cell carcinoma (RCC) is a well-recognized and interesting phenomenon that is poorly understood and rarely documented. There are very few reported cases of spontaneously regressed primary RCC. We present a 63-year-old male with a biopsy-proven RCC that regressed with complete resolution of symptoms.

Urinary ultrasonography in screening incidental renal cell carcinoma: is it obligatory?

PURPOSE

To analyze the rate of incidental renal carcinoma in patients with no upper urinary tract symptoms (UUTS) or hematuria depending on the sonography reports and medical records of the patients and to determine whether there is a need for routine US screening for RCC.

MATERIALS AND METHODS

We reviewed the reports of 18.686 consecutive urinary US examinations performed in our department between March 1995 and February 2008. A total of 18.203 urinary US examinations formed the study group. Patients with UUTS, patients with presumed diagnosis of or previously diagnosed renal masses, and patients with hematuria were excluded.

RESULTS

There were 11,654 male and 6,549 female patients with a mean age of 55 years. Ultrasonography revealed incidental solid renal masses in 0.44% of the patients. Seven of the 81 patients with incidentally detected renal masses could not be followed up. Thirty-eight of the remaining 74 patients had masses that were proved to be benign with other imaging techniques. Thirty-six of the 74 patients with preoperative diagnosis of renal tumor underwent surgery, and the histopathological diagnosis was renal cell carcinoma in all patients. One patient expired in the postoperative 18th month due to the progression of the metastatic disease. The rest of the patients with malignant renal tumor are disease free and are still under follow-up.

CONCLUSION

The rate of incidental renal cancer in patients without UUTS is found to be 0.20%. We believe that scanning for incidental renal masses is not obligatory except for the patients with symptoms suggestive of renal carcinoma.

Epidemiology and risk factors for kidney cancer

After more than two decades of rising rates, in recent years the total kidney cancer incidence worldwide has shown signs of stabilizing, or even decreasing. In adults, kidney cancer consists of renal cell carcinoma (RCC), the predominant form, and renal transitional cell carcinoma (RTCC); these types primarily arise in the renal parenchyma and renal pelvis, respectively. Although temporal trends by kidney cancer type are not well established worldwide, incidence of RCC in the US has continued to rise, mainly for early-stage tumors, while that of RTCC has declined, and total kidney cancer mortality rates have leveled. Stabilization of kidney cancer mortality rates has also been reported in Europe. These trends are consistent with reports of increasing incidental diagnoses and a downward shift in tumor stage and size in clinical series. The changing prevalence of known risk factors for RCC, including cigarette smoking, obesity, and hypertension, is also likely to affect incidence trends, although their relative impact may differ between populations. Accumulating evidence suggests an etiologic role in RCC for physical activity, alcohol consumption, occupational exposure to trichloroethylene, and high parity among women, but further research is needed into the potential causal effects of these factors. Genetic factors and their interaction with environmental exposures are believed to influence risk of developing RCC, but a limited number of studies using candidate-gene approaches have not produced conclusive results. Large consortium efforts employing genome-wide scanning technology are underway, which hold promise for novel discoveries in renal carcinogenesis.

Effect of advanced imaging technology on how biopsies are done and who does them

PURPOSE

To assess national levels and trends in utilization of biopsy procedures during the past decade and investigate the relative roles of biopsy approaches (open, endoscopic, and percutaneous) and physician specialties.

MATERIALS AND METHODS

Institutional review board approval was not necessary because only public domain data were used. Aggregated Medicare claims data were used to determine utilization of biopsies performed in 10 anatomic regions from 1997 to 2008. Utilization levels according to biopsy approach and anatomic region were calculated. Trends in the relative utilization of percutaneous needle biopsy (PNB) and imaging-guided percutaneous biopsy (IGPB) were assessed. The relative roles of radiologists and nonradiologists in the performance of all biopsies, PNBs, and IGPBs were evaluated.

RESULTS

Biopsy procedures with all approaches increased from 1380 to 1945 biopsies per 100,000 Medicare enrollees between 1997 and 2008, which represents a compound annual growth rate (CAGR) of 3%. Utilization of non-PNBs fell, while the absolute level and relative share of PNBs increased. In 2008, 67% of all biopsies were performed by using a percutaneous route. IGPB as a percentage of all PNBs increased over time in the regions for which data were available. Radiology was the leading specialty providing biopsy services. The total number of biopsies performed by radiologists increased at a CAGR of 8%, and radiologists' share of all biopsies increased from 35% to 56%.

CONCLUSION

During the past decade, there was continuing substitution away from invasive approaches and non-imaging-guided percutaneous approaches in favor of PNBs and IGPBs, likely related to increasing use of advanced imaging modalities for biopsy guidance. Consequently, radiologists are performing an increasing share of biopsies across all anatomic regions.