Screening computed tomography: will it result in overdiagnosis of renal carcinoma?

Risk-stratified screening for the early detection of kidney cancer

Earlier detection and screening for kidney cancer has been identified as a key research priority, however the low prevalence of the disease in unselected populations limits the cost-effectiveness of screening. Risk-stratified screening for kidney cancer may improve early detection by targeting high-risk individuals whilst limiting harms in low-risk individuals, potentially increasing the cost-effectiveness of screening. A number of models have been identified which estimate kidney cancer risk based on both phenotypic and genetic data, and while several of the former have been shown to identify individuals at high-risk of developing kidney cancer with reasonable accuracy, current evidence does not support including a genetic component. Combined screening for lung cancer and kidney cancer has been proposed, as the two malignancies share some common risk factors. A modelling study estimated that using lung cancer risk models (currently used for risk-stratified lung cancer screening) could capture 25% of patients with kidney cancer, which is only slightly lower than using the best performing kidney cancer-specific risk models based on phenotypic data (27%-33%). Additionally, risk-stratified screening for kidney cancer has been shown to be acceptable to the public. The following review summarises existing evidence regarding risk-stratified screening for kidney cancer, highlighting the risks and benefits, as well as exploring the management of potential harms and further research needs.

Screening for renal cell carcinoma in renal transplant recipients: a single-centre retrospective study

OBJECTIVES

The primary objective of our study was to evaluate the effectiveness of renal cell carcinoma (RCC) screening in renal transplant (RT) recipients.

DESIGN

Single-centre retrospective study.

SETTING AND PARTICIPANTS

1998 RT recipients who underwent RT at Memorial Hermann Hospital (MHH) Texas Medical Center (TMC) between 1 January 1999 and 31 December 2019 were included and we identified 16 patients (0.8%) with RCC. An additional four patients with RCC who underwent RT elsewhere but received follow-up at MHH TMC were also included. Subject races included white (20%), black (50%), Hispanic (20%) and Asian (10%).

OUTCOME MEASURES

The RCC stage at diagnosis and outcomes were compared between patients who were screening versus those who were not.

RESULTS

We identified a total of 20 patients with post-RT RCC, 75% of whom were men. The median age at diagnosis was 56 years. RCC histologies included clear cell (75%), papillary (20%) and chromophobe (5%). Patients with post-RT RCC who had screening (n=12) underwent ultrasound or CT annually or every 2 years, whereas eight patients had no screening. All 12 patients who had screening had early-stage disease at diagnosis (stage I (n=11) or stage II (n=1)) and were cured by nephrectomy (n=10) or cryotherapy (n=2). In patients who had no screening, three (37.5%) had stage IV RCC at diagnosis and all of whom died of metastatic disease. There was a statistically significant difference in RCC-specific survival in patients who were screened (p=0.01) compared with those who were not screened.

CONCLUSION

All RT recipients who had RCC diagnosed based on screening had early-stage disease and there were no RCC-related deaths. Screening is an effective intervention in RT recipients to reduce RCC-related mortality.

Multi-detector computed tomography (MDCT) evaluation of synchronous renal cell carcinoma and other solid malignancies

Background

Multiple primary malignant neoplasms (MPMNs) became more prevalent as the population aged and medical technology progressed. The purpose of this research was to review the findings of multidetector computed tomography (MDCT) in synchronous renal cell carcinoma and other solid tumors.

Results

31 individuals with synchronous renal cell carcinoma and additional solid cancers were included in this retrospective analysis. CT scanning was carried out using 64 MDCT scanners. All sixty-two malignancies were undergoing pathological assessment. Out of 685 patients with renal cell carcinoma, 31 individuals were identified with another primary solid cancer that occurred concurrently. All of our instances were pathologically verified. In all 31 individuals, clear renal cell carcinoma was found. The most frequent extra-renal malignancies were hepatocellular carcinoma (10/31), followed by breast carcinoma (4/31), non-Hodgkin lymphoma (4/31), bronchogenic carcinoma (3/31), colonic carcinoma (3/31), prostatic carcinoma (2/31), urinary bladder carcinoma (1/31), periampullary carcinoma (1/31), mucoepidermoid carcinoma (1/31) and skin squamous cell carcinoma (1/31) as well as malignant hemangioendothelioma (1/31).

Conclusion

MDCT scanning was an accurate imaging method for diagnosing synchronous renal cell carcinoma and other solid tumors. Even in the face of numerous cancers, the goal of therapy in cancer patients must always be curative. During the pretreatment examination, the potential of synchronous double malignancies with renal cell carcinoma should be explored.

Incidence and Outcomes of Early Cancers After Kidney Transplantation

Outcomes of early cancers after kidney transplantation are not well-understood. We included recipients of first live and deceased donor kidney transplants who developed de novo cancers in Australia and New Zealand between 1980–2016. We compared the frequency and stage of specific cancer types that developed early (≤12-months) and late (>12-months) post-transplantation. Risk factors for death were evaluated using multivariable Cox regression analyses. Of 2,759 recipients who developed de novo cancer, followed-up for 40,035 person-years, 243 (8.8%) patients were diagnosed with early cancer. Post-transplant lymphoproliferative disease, urinary cancers and melanoma were the most common cancer types (26%, 18%, and 12%) and the majority were either in-situ or locally invasive lesions (55%, 84%, and 86%). Tumors arising early from the gastrointestinal and respiratory systems were uncommon but aggressive, with 40% presenting with metastatic disease at time of diagnosis. Overall, 32% of patients with early cancers died within a median of 4.7 months (IQR:0.6–16) post-diagnosis and 91% were cancer-related deaths. Older recipient and donor age were associated with an increased risk of all-cause death. Early cancers, though infrequent in kidney transplant recipients, are associated with poor outcomes, as nearly 1 in 3 died from cancer-related death; with majority of deaths occurring within 12-months of cancer diagnosis.

Screening programs for renal cell carcinoma: a systematic review by the EAU young academic urologists renal cancer working group

PURPOSE

To systematically review studies focused on screening programs for renal cell carcinoma (RCC) and provide an exhaustive overview on their clinical impact, potential benefits, and harms.

METHODS

A systematic review of the recent English-language literature was conducted according to the European Association of Urology guidelines and the PRISMA statement recommendations (PROSPERO ID: CRD42021283136) using the MEDLINE, Cochrane Central Register of Controlled Trials, and ClinicalTrials.gov databases. Risk-of-bias assessment was performed according to the QUality In Prognosis Studies (QUIPS) tool.

RESULTS

Overall, nine studies and one clinical trials were included. Eight studies reported results from RCC screening programs involving a total of 159 136 patients and four studies reported screening cost-analysis. The prevalence of RCC ranged between 0.02 and 0.22% and it was associated with the socio-demographic characteristics of the subjects; selection of the target population decreased, overall, the screening cost per diagnosis.

CONCLUSIONS

Despite an increasing interest in RCC screening programs from patients and clinicians there is a relative lack of studies reporting the efficacy, cost-effectiveness, and the optimal modality for RCC screening. Targeting high-risk individuals and/or combining detection of RCC with other health checks represent pragmatic options to improve the cost-effectiveness and reduce the potential harms of RCC screening.

Validation and public health modelling of risk prediction models for kidney cancer using the UK Biobank

OBJECTIVES

To externally validate risk models for the detection of kidney cancer, as early detection of kidney cancer improves survival and stratifying the population using risk models could enable an individually tailored screening programme.

METHODS

We validated the performance of 30 existing phenotypic models predicting the risk of kidney cancer in the UK Biobank cohort (n = 450 687). We compared the discrimination and calibration of models for men, women, and a mixed-sex cohort. Population level data were used to estimate model performance in a screening scenario for a range of risk thresholds (6-year risk: 0.1-1.0%).

RESULTS

In all, 10 models had reasonable discrimination (area under the receiver-operating characteristic curve >0.60), although some had poor calibration. Modelling demonstrated similar performance of the best models over a range of thresholds. The models showed an improvement in ability to identify cases compared to age- and sex-based screening. All the models performed less well in women than men.

CONCLUSIONS

The present study is the first comprehensive external validation of risk models for kidney cancer. The best-performing models are better at identifying individuals at high risk of kidney cancer than age and sex alone; however, the benefits are relatively small. Feasibility studies are required to determine applicability to a screening programme.

Preoperative prediction of the stage, size, grade, and necrosis score in clear cell renal cell carcinoma using MRI-based radiomics

PURPOSE

Clear cell renal cell carcinoma (ccRCC) is the most common subtype of renal cell carcinoma. Currently, there is a lack of noninvasive methods to stratify ccRCC prognosis prior to any invasive therapies. The purpose of this study was to preoperatively predict the tumor stage, size, grade, and necrosis (SSIGN) score of ccRCC using MRI-based radiomics.

METHODS

A multicenter cohort of 364 histopathologically confirmed ccRCC patients (272 low [< 4] and 92 high [≥ 4] SSIGN score) with preoperative T2-weighted and T1-contrast-enhanced MRI were retrospectively identified and divided into training (254 patients) and testing sets (110 patients). The performance of a manually optimized radiomics model was assessed by measuring accuracy, sensitivity, specificity, area under receiver operating characteristic curve (AUROC), and area under precision-recall curve (AUPRC) on an independent test set, which was not included in model training. Lastly, its performance was compared to that of a machine learning pipeline, Tree-Based Pipeline Optimization Tool (TPOT).

RESULTS

The manually optimized radiomics model using Random Forest classification and Analysis of Variance feature selection methods achieved an AUROC of 0.89, AUPRC of 0.81, accuracy of 0.89 (95% CI 0.816-0.937), specificity of 0.95 (95% CI 0.875-0.984), and sensitivity of 0.72 (95% CI 0.537-0.852) on the test set. The TPOT using Extra Trees Classifier achieved an AUROC of 0.94, AUPRC of 0.83, accuracy of 0.89 (95% CI 0.816-0.937), specificity of 0.95 (95% CI 0.875-0.984), and sensitivity of 0.72 (95% CI 0.537-0.852) on the test set.

CONCLUSION

Preoperative MR radiomics can accurately predict SSIGN score of ccRCC, suggesting its promise as a prognostic tool that can be used in conjunction with diagnostic markers.

A Decision Analysis Evaluating Screening for Kidney Cancer Using Focused Renal Ultrasound

BACKGROUND

Screening for renal cell carcinoma (RCC) has been identified as a key research priority; however, no randomised control trials have been performed. Value of information analysis can determine whether further research on this topic is of value.

OBJECTIVE

To determine (1) whether current evidence suggests that screening is potentially cost-effective and, if so, (2) in which age/sex groups, (3) identify evidence gaps, and (4) estimate the value of further research to close those gaps.

DESIGN, SETTING, AND PARTICIPANTS

A decision model was developed evaluating screening in asymptomatic individuals in the UK. A National Health Service perspective was adopted.

INTERVENTION

A single focused renal ultrasound scan compared with standard of care (no screening).

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Expected lifetime costs, quality-adjusted life years (QALYs), and incremental cost-effectiveness ratio (ICER), discounted at 3.5% per annum.

RESULTS AND LIMITATIONS

Given a prevalence of RCC of 0.34% (0.18-0.54%), screening 60-yr-old men resulted in an ICER of £18 092/QALY (€22 843/QALY). Given a prevalence of RCC of 0.16% (0.08-0.25%), screening 60-yr-old women resulted in an ICER of £37327/QALY (€47 129/QALY). In the one-way sensitivity analysis, the ICER was <£30000/QALY as long as the prevalence of RCC was ≥0.25% for men and ≥0.2% for women at age 60yr. Given the willingness to pay a threshold of £30000/QALY (€37 878/QALY), the population-expected values of perfect information were £194 million (€244 million) and £97 million (€123 million) for 60-yr-old men and women, respectively. The expected value of perfect parameter information suggests that the prevalence of RCC and stage shift associated with screening are key research priorities.

CONCLUSIONS

Current evidence suggests that one-off screening of 60-yr-old men is potentially cost-effective and that further research into this topic would be of value to society.

PATIENT SUMMARY

Economic modelling suggests that screening 60-yr-old men for kidney cancer using ultrasound may be a good use of resources and that further research on this topic should be performed.

A comparative study of ultrasound and cross-sectional imaging for detection of small renal masses: anatomic factors and radiologist's experience

Objective:

To evaluate anatomic factors and radiologist's experience in the detection of solid renal masses on ultrasonography.

Methods:

We searched for solid renal masses diagnosed on cross-sectional imaging from 2007 to 2017 that also had previous ultrasonography from the past 6 months. The following features were evaluated: nodule size, laterality, location and growth pattern, patient body mass index and radiologist's experience in ultrasound. In surgically resected cases, pathologic reports were evaluated. Unpaired t test and χ² test were used to evaluate differences among subgroups, using R-statistics. Statistical significance was set at p<0.05.

Results:

The initial search of renal nodules on cross-sectional imaging resulted in 428 lesions and 266 lesions were excluded. Final cohort included 162 lesions and, of those, 108 (67%) were correctly detected on ultrasonography (Group 1) and 54 (33%) were missed (Group 2). Comparison of Groups 1 and 2 were as follows, respectively: body mass index (27.7 versus 27.1; p=0.496), size (2.58cm versus 1.74cm; p=0.003), laterality (54% versus 59% right sided; p=0.832), location (27% versus 22% upper pole; p=0.869), growth pattern (25% versus 28% endophytic; p=0.131) and radiologist's experience (p=0.300). From surgically resected cases, histology available for Group 1 was clear cell (n=11), papillary (n=15), chromophobe (n=2) renal cell carcinoma, oncocytoma (n=1), and, for Group 2, clear cell (n=7), papillary (n=5) renal cell carcinoma, oncocytoma (n=2), angiomyolipoma, chromophobe renal cell carcinoma, and interstitial pyelonephritis (n=1, each).

Conclusion:

Size was the only significant parameter related to renal nodule detection on ultrasound.

Current evidence on screening for renal cancer

Renal cell carcinoma (RCC) incidence is increasing worldwide. A high proportion of individuals are asymptomatic at diagnosis, but RCC has a high mortality rate. These facts suggest that RCC meets some of the criteria for screening, and a new analysis shows that screening for RCC could potentially be cost-effective. Targeted screening of high-risk individuals is likely to be the most cost-effective strategy to maximize the benefits and reduce the harms of screening. However, the size of the benefit of earlier initiation of treatment and the overall cost-effectiveness of screening remains uncertain. The optimal screening modality and target population is also unclear, and uncertainties exist regarding the specification and implementation of a screening programme. Before moving to a fully powered trial of screening, future work should focus on the following: developing and validating accurate risk prediction models; developing non-invasive methods of early RCC detection; establishing the feasibility, public acceptability and potential uptake of screening; establishing the prevalence of RCC and stage distribution of RCC detected by screening; and evaluating the potential harms of screening, including the impact on quality of life, overdiagnosis and over-treatment.

Frequency, incidence and survival outcomes of clear cell renal cell carcinoma in the United States from 1973 to 2014: A SEER-based analysis

The epidemiological and prognostic data focusing on clear cell renal cell carcinoma (ccRCC) are rarely presented. This study was aimed to define the frequency, incidence, and survival outcomes of ccRCC in the United States.The Surveillance, Epidemiology, and End Results (SEER) database was searched for patients with ccRCC from 1973 to 2014. Two patient cohorts were utilized: patient cohorts of SEER 18 registries and 9 registries. Overall survival was determined with Kaplan-Meier method and compared across groups with log-rank test.The incidence rate of ccRCC increased with advancing age, peaked in individuals aged 60 to 79 years, and declined in individuals aged ≥80 years. The incidence rate of ccRCC was significantly higher in males than females (1.94: 1, P < .0001), in Whites than Blacks or others (1:0.79:0.91, P < .0001). The incidence rate of ccRCC with right side as primary origin was slightly but significantly higher than that with left side as primary origin (1:0.96, P = .0006). The incidence rate of ccRCC in Grade II was higher than other grades. Generally, the incidence rates of ccRCC in most circumstances started to surge in the middle 1990s. Survival outcomes of ccRCC worsened with advancing age at diagnosis, tumor grade, and stage. A better prognosis was observed in females than males, in Whites than Blacks, and in individuals diagnosed in 2006 to 2014 than 1973 to 2005.To the best of our knowledge, the present study firstly presented long-term and updated epidemiological and prognostic data concerning ccRCC in the United States. Significant differences in incidence rates and survival outcomes stratified by different variables were identified.

Epidemiology and screening for renal cancer

PURPOSE

The widespread use of abdominal imaging has affected the epidemiology of renal cell carcinoma (RCC). Despite this, over 25% of individuals with RCC have evidence of metastases at presentation. Screening for RCC has the potential to downstage the disease.

METHODS

We performed a literature review on the epidemiology of RCC and evidence base regarding screening. Furthermore, contemporary RCC epidemiology data was obtained for the United Kingdom and trends in age-standardised rates of incidence and mortality were analysed by annual percentage change statistics and joinpoint regression.

RESULTS

The incidence of RCC in the UK increased by 3.1% annually from 1993 through 2014. Urinary dipstick is an inadequate screening tool due to low sensitivity and specificity. It is unlikely that CT would be recommended for population screening due to cost, radiation dose and increased potential for other incidental findings. Screening ultrasound has a sensitivity and specificity of 82-83% and 98-99%, respectively; however, accuracy is dependent on tumour size. No clinically validated urinary nor serum biomarkers have been identified. Major barriers to population screening include the relatively low prevalence of the disease, the potential for false positives and over-diagnosis of slow-growing RCCs. Individual patient risk-stratification based on a combination of risk factors may improve screening efficiency and minimise harms by identifying a group at high risk of RCC.

CONCLUSION

The incidence of RCC is increasing. The optimal screening modality and target population remain to be elucidated. An analysis of the benefits and harms of screening for patients and society is warranted.

Update on Screening for Urological Malignancies

Urological malignancies are a major source of morbidity and mortality in men over 40. Screening for those malignancies has a potential benefit of reducing both. However, even after more than two decades of screening for prostate cancer, the implications of most resulting information are still a matter of debate. Controversy extends over several aspects of prostate cancer screening programs, including age of onset, defining populations at risk, most appropriate intervals, as well as the optimal methods to be used for screening. The medical community is still divided regarding the effectiveness of prostate cancer-related death prevention and its benefits-to-harms ratio, reflecting an inconsistency regarding screening recommendations. Similarly, benefits of screening for urothelial and kidney tumors are yet lacking high-level evidence, although recent evidence supports screening of populations at risk. Clearly, the current era of evolving molecular and genetic biomarkers harbors the potential to change screening practice. In this paper, we review current guidelines as well as giving an update on new developments which might influence screening strategies in common urological malignancies.

Kidney Cancer Incidence in California: End of the Trend?

Background and Objective: Since the 1990s, multiple studies have reported on an increased incidence of renal cell carcinomas (RCC), which has been considered incidental to the high use of abdominal diagnostic imaging. This population-based study used data from the California Cancer Registry to (i) update trends in RCC incidence and mortality by several tumor and demographic characteristics after reports of decreased use of diagnostic imaging in recent years, and (ii) examine changes in surgical treatment for early-stage RCC.

Methods: Records of patients diagnosed with RCC from 1988 through 2013 and mortality data from the same period were examined. Joinpoint regression was used to estimate annual percent changes in age-adjusted RCC incidence and mortality rates, stratified by sex, race/ethnicity, stage at diagnosis, grade, and tumor size. Trends in the proportion of partial or total/radical nephrectomies were evaluated by Cochran-Armitage tests.

Results: A total of 77,363 incident cases of RCC and 28,590 deaths were evaluated. While mortality rates significantly decreased, the incidence of small localized RCC increased in virtually all groups examined after the mid-1990s until 2008-2009, when incidence trends stabilized in all groups concomitant with a decrease in imaging. The proportion of partial nephrectomies among patients with small localized tumors increased from 13.8% in 1988 to 74.6% in 2013.

Conclusions: Earlier trends in RCC were consistent with the incidental discovery of small tumors. In parallel with the increase in early-stage RCC, the use of partial nephrectomies increased markedly. Following the decreased use of advanced diagnostic imaging, the trend of increasing RCC incidence appears to have ended in California.

Meta-analysis of the prevalence of renal cancer detected by abdominal ultrasonography

BACKGROUND

The potential for an ultrasound-based screening programme for renal cell carcinoma (RCC) to improve survival through early detection has been the subject of much debate. The prevalence of ultrasound-detected asymptomatic RCC is an important first step to establishing whether a screening programme may be feasible.

METHODS

A systematic search of MEDLINE and Embase was performed up to March 2016 to identify studies reporting the prevalence of renal masses and RCC. Two populations of patients were chosen: asymptomatic individuals undergoing screening ultrasonography and patients undergoing ultrasonography for abdominal symptoms not related to RCC. A random-effects meta-analysis was performed. Study quality was evaluated using a validated eight-point checklist.

RESULTS

Sixteen studies (413 551 patients) were included in the final analysis. The pooled prevalence of renal mass was 0·36 (95 per cent c.i. 0·23 to 0·52) per cent and the prevalence of histologically proven RCC was 0·10 (0·06 to 0·15) per cent. The prevalence of RCC was more than double in studies from Europe and North America than in those from Asia: 0·17 (0·09 to 0·27) versus 0·06 (0·03 to 0·09) per cent respectively. Data on 205 screen-detected RCCs showed that 84·4 per cent of tumours were stage T1-T2 N0, 13·7 per cent were T3-T4 N0, and only 2·0 per cent had positive nodes or metastases at diagnosis.

CONCLUSION

At least one RCC would be detected per 1000 individuals screened. The majority of tumours identified are early stage (T1-T2).

Monitoring tumor response with [18F]FMAU in a sarcoma-bearing mouse model after liposomal vinorelbine treatment

OBJECTIVE

Previous studies have shown that the accumulation level of FMAU in tumor is proportional to its proliferation rate. This study demonstrated that 2'-deoxy-2'-[(18)F]fluoro-β-d-arabinofuranosyluracil ([(18)F]FMAU) is a promising PET probe for noninvasively monitoring the therapeutic efficacy of 6% PEGylated liposomal vinorelbine (lipo-VNB) in a subcutaneous murine NG4TL4 sarcoma mouse model.

METHODS

Female syngenic FVB/N mice were inoculated with NG4TL4 cells in the right flank. After tumor size reached 150 ± 50 mm(3) (day 0), lipo-VNB (5mg/kg) was intravenously administered on days 0, 3 and 6. To monitor the therapeutic efficacy of lipo-VNB, [(18)F]FMAU PET was employed to evaluate the proliferation rate of tumor, and it was compared with that observed from [(18)F]FDG/[(18)F]fluoroacetate PET. The expression of proliferating cell nuclear antigen (PCNA) in tumor during treatment was determined by semiquantitative analysis of immunohistochemical staining.

RESULTS

A significant inhibition (p<0.001) in tumor growth was observed on day 3 after a single dose treatment. The tumor-to-muscle ratio (T/M) derived from [(18)F]FMAU-PET images of lipo-VNB-treated group declined from 2.33 ± 0.16 to 1.26 ± 0.03 after three doses of treatment, while that of the control remained steady. The retarded proliferation rate of lipo-VNB-treated sarcoma was confirmed by PCNA immunohistochemistry staining. However, both [(18)F]FDG and [(18)F]fluoroacetate microPET imaging did not show significant difference in T/M between the therapeutic and the control groups throughout the entire experimental period.

CONCLUSION

Lipo-VNB can effectively impede the growth of NG4TL4 sarcoma. [(18)F]FMAU PET is an appropriate modality for early monitoring of the tumor response during the treatment course of lipo-VNB.

The American College of Radiology strategy for managing incidental findings on abdominal computed tomography

There has been a dramatically increased awareness of the substantial clinical challenges posed by incidental findings found on cross-sectional imaging. In 2006, an Incidental Findings Committee was organized under the Body Imaging Commission in the American College of Radiology to create a consistent and rational approach to these findings. This article describes the formation, process of developing recommendations, and future tasks of this committee.

Screening for renal cancer in recipients of kidney transplants

BACKGROUND

Renal cancer is the most common solid organ cancer in the kidney transplant population with an excess risk ~ 5-fold greater than the general population. It is uncertain whether routine screening for renal cancer is cost-effective. The aim of our study is to estimate the costs and health benefits of ultrasonographic (US) screening for renal cancer in the kidney transplant population.

METHODS

A Markov model was developed to compare the costs and benefits in a cohort of kidney transplant recipients (n = 1000, aged 18-69 years), who underwent annual and biennial US screening for renal cancer, compared with a cohort that did not.

RESULTS

For recipients of kidney transplants aged 18-69 years, the incremental cost-effectiveness ratio (ICER) for routine US screening ranged from $252,100/LYS for biennial screening to $320,988/LYS for annual screening. A total of two and one cancer deaths were averted in the annually and biennially screened population, with a relative cancer-specific mortality reduction by 25% and 12.5%, respectively. Using a series of sensitivity analyses, the ICER was most sensitive to the costs and test specificity of ultrasonography, prevalence of disease, and the risk of graft failure in the screened population.

CONCLUSIONS

Routine screening for renal cancer may reduce the risk of cancer-related deaths in recipients of kidney transplants. Uncertainties, however, exist in the model's influential variables including the risk of graft failure among those who received contrast-enhanced diagnostic computer tomography. Given the available evidence, routine screening for renal cancers may not be cost-effective for recipients of kidney transplants.

Monitoring of tumor response to chemotherapy in vivo by a novel small-molecule detector of apoptosis

Utilization of molecular imaging of apoptosis for clinical monitoring of tumor response to anti-cancer treatments in vivo is highly desirable. To address this need, we now present ML-9 (butyl-2-methyl-malonic acid; MW = 173), a rationally designed small-molecule detector of apoptosis, based on a novel alkyl-malonate motif. In proof-of-concept studies, induction of apoptosis in tumor cells by various triggers both in vitro and in vivo was associated with marked uptake of (3)H-ML-9 administered in vivo, in correlation with the apoptotic hallmarks of DNA fragmentation, caspase-3 activation and membrane phospholipid scrambling, and with correlative tumor regression. ML-9 uptake following chemotherapy was tumor-specific, with rapid clearance of the tracer from the blood and other non-target organs. Excess of non-labeled "cold" compound competitively blocked ML-9 tumor uptake, thus demonstrating the specificity of ML-9 binding. ML-9 may therefore serve as a platform for a novel class of small-molecule imaging agents for apoptosis, useful for assessment of tumor responsiveness to treatment.

Contemporary epidemiology of renal cell cancer

We analyzed renal cell cancer incidence patterns in the United States and reviewed recent epidemiologic evidence with regard to environmental and host genetic determinants of renal cell cancer risk. Renal cell cancer incidence rates continued to rise among all racial/ethnic groups in the United States, across all age groups, and for all tumor sizes, with the most rapid increases for localized stage disease and small tumors. Recent cohort studies confirmed the association of smoking, excess body weight, and hypertension with an elevated risk of renal cell cancer, and suggested that these factors can be modified to reduce the risk. There is increasing evidence for an inverse association between renal cell cancer risk and physical activity and moderate intake of alcohol. Occupational exposure to trichloroethylene has been positively associated with renal cell cancer risk in several recent studies, but its link with somatic mutations of the von Hippel-Lindau gene has not been confirmed. Studies of genetic polymorphisms in relation to renal cell cancer risk have produced mixed results, but genome-wide association studies with larger sample size and a more comprehensive approach are underway. Few epidemiologic studies have evaluated risk factors by subtypes of renal cell cancer defined by somatic mutations and other tumor markers.

Bilder in der Urologie: Faszination und Perspektiven

In contrast to other countries (e.g., USA) the German urologist routinely utilizes imaging in order to evaluate urological disorders. Ultrasound as a basic tool has acquired importance similar to the physical examination or the patient history. Because of its minimal invasiveness and low cost, it is increasingly utilized as a first-line exam.In correlation with the patient history and laboratory data more invasive imaging studies are performed and in unclear cases or in the preoperative work-up more extensive imaging procedures like computed tomography (CT) or magnetic resonance imaging (MRI) are utilized. Even in emergency situations the urologist is able to guide interventions under ultrasound or conventional X-ray guidance (e.g., percutaneous drainage of dilated kidney), which resulted in a much lower complication rate of the various procedures. In those cases in which ultrasound is technically infeasible or in unclear cases CT and MRI are used as problem-solving procedures and are able to give the correct diagnosis in a large percentage of cases.After a brief historical overview, newer modalities and innovative techniques are explored and presented. Assuming that these innovative approaches lead to more accurate diagnosis and staging of various neoplastic and nonneoplastic conditions, treatment can be performed in earlier stages of diseases and better stage-adapted treatment can be offered to the patients.

Early detection of tumor response to chemotherapy by 3'-deoxy-3'-[18F]fluorothymidine positron emission tomography: the effect of cisplatin on a fibrosarcoma tumor model in vivo

We have assessed the potential of [18F]fluorothymidine positron emission tomography ([18F]FLT-PET) to measure early cytostasis and cytotoxicity induced by cisplatin treatment of radiation-induced fibrosarcoma 1 (RIF-1) tumor-bearing mice. Cisplatin-mediated arrest of tumor cell growth and induction of tumor shrinkage at 24 and 48 hours, respectively, were detectable by [18F]FLT-PET. At 24 and 48 hours, the normalized uptake at 60 minutes (tumor/liver radioactivity ratio at 60 minutes after radiotracer injection; NUV60) for [18F]FLT was 0.76 +/- 0.08 (P = 0.03) and 0.51 +/- 0.08 (P = 0.03), respectively, compared with controls (1.02 +/- 0.12). The decrease in [18F]FLT uptake at 24 hours was associated with a decrease in cell proliferation assessed immunohistochemically (a decrease in proliferating cell nuclear antigen labeling index, LI(PCNA), from 14.0 +/- 2.0% to 6.2 +/- 1.0%; P = 0.001), despite the lack of a change in tumor size. There were G1-S and G2-M phase arrests after cisplatin treatment, as determined by cell cycle analysis. For the quantitative measurement of tumor cell proliferation, [18F]FLT-PET was found to be superior to [18F]fluorodeoxyglucose-PET (NUV60 versus LIPCNA: r = 0.89, P = 0.001 and r = 0.55, P = 0.06, respectively). At the biochemical level, we found that the changes in [18F]FLT and [18F]fluorodeoxyglucose uptake were due to changes in levels of thymidine kinase 1 protein, hexokinase, and ATP. This work supports the further development of [18F]FLT-PET as a generic pharmacodynamic readout for early quantitative imaging of drug-induced changes in cell proliferation in vivo.

Parenchymal imaging adds diagnostic utility in evaluating haematuria

OBJECTIVE

To compare the findings of renal ultrasonography (US) in the evaluation of patients with and with no haematuria. The increased use of cross-sectional imaging and US has led to a dramatic improvement in the diagnosis of renal masses, such that computed tomography and/or US have been integrated into the diagnostic evaluation of haematuria, and many more incidental renal lesions are now detected. Thus it is possible that the lesions identified during evaluation for haematuria are incidental, i.e. identified serendipitously, and unrelated to the haematuria.

PATIENTS AND METHODS

We retrospectively compared the US findings obtained from 301 patients referred for new-onset haematuria to those obtained from 600 patients being evaluated for other than urological reasons. All imaging and patient charts were reviewed to verify the clinical and radiological data.

RESULTS

Haematuria was associated with all renal abnormalities, with an odds ratio (OR, 95% confidence interval) of 4.7 (3.6-7.3). Importantly, haematuria was associated with a renal mass, with an OR of 6.7 (2.8-16.3). Subset analysis revealed that patients with macroscopic and microscopic haematuria had significantly more renal abnormalities (OR 4.7, 2.7-8.2, and 5.3, 3.2-8.8, respectively) and renal masses (OR 7.3, 2.7-20.3, and 6.5, 2.3-18.6, respectively) than controls.

CONCLUSIONS

Both macroscopic and microscopic haematuria are associated with a greater risk of identifying renal lesions. This supports the conclusion that the renal lesions identified with modern imaging techniques during the evaluation of both microscopic and macroscopic haematuria are not serendipitous.

[New techniques in computed tomography. Significance for urology]

Computed tomographic (CT) imaging has become the modality of choice for the assessment of patients with urological malignancies. Recently, multi-slice CT imaging was introduced, providing faster acquisition times and higher resolution leading to improved image quality. Several studies show that thin-slice, high-resolution acquisition strategies lead to an improved accuracy for T-staging, especially of renal cell carcinomas. Three-dimensional post-processing techniques for the visualization of the vascular supply as well as the ureter (CT-angiography and CT-urography) are helpful for surgical planning. Compared to conventional imaging strategies unenhanced CT images render higher sensitivities and specificities for detecting stone disease in patients with acute flank pain. In the USA unenhanced CT imaging has almost replaced conventional urography, as no contrast agent is administered and the examination time is shorter. PET/CT examinations provide information on the morphology and function of tumors in one examination. However, there are only few data available for the assessment of urologic tumors.