Predicting the Histology of Renal Masses Using Preoperative Doppler Ultrasonography

Effects of Contrast-Enhanced Ultrasound of Indeterminate Renal Masses on Patient Clinical Management: Retrospective Analysis From 2 Institutions

OBJECTIVES

To investigate the long-term impact of contrast-enhanced ultrasound (CEUS) on the treatment of patients with indeterminate renal masses.

METHODS

In this retrospective study, consecutive charts of all patients receiving renal CEUS at 1 of 2 academic medical centers between January 1, 2014, and December 31, 2018, were reviewed. Patients were included in the study if they had documented chronic renal disease (estimated glomerular filtration rate < 60 mL/min/1.73 m² ) or prior nephrectomy and received CEUS for a previously untreated renal mass.

RESULTS

A total of 215 lesions in 157 patients were used for analysis. Contrast-enhanced ultrasound provided a final treatment recommendation in 71.6% of lesions (154 of 215). Of these 154 lesions, 7.8% (12 of 154) were lost to follow-up despite CEUS suggesting malignancy; 15.6% (24 of 154) went directly for surgical intervention, with malignancy confirmed by pathologic results in 87.5% (21 of 24) of these cases; and the remaining 76.6% (118 of 154) were deemed benign and required no additional follow-up. Of the 118 lesions diagnosed by CEUS as benign and requiring no follow-up, none showed evidence of later renal cell carcinoma development and, only 5.1% (6 of 118) of the total population was referred for further cross-sectional imaging of the mass in question. In 28.4% of all lesions (61 of 215), CEUS resulted in a recommendation for surveillance imaging at a 6- to 12-month interval, and less than 10% (6 of 61) of these underwent additional cross-sectional imaging within the recommended 6 months after CEUS.

CONCLUSIONS

These findings highlight the impact of CEUS on clinical treatment of indeterminate renal masses, including reducing the use of the potentially nephrotoxic contrast agents and providing a direct pathway to transplant.

Peritoneal Dialysis and Retroperitoneal Laparoscopic Radical Nephrectomy: A Favorable Experience With a Patient Complicated by Renal Cell Carcinoma

Peritoneal dialysis (PD) is an accepted modality for managing end-stage kidney disease. We herein report a 75-year-old female patient on chronic PD who was complicated by renal cell carcinoma. She was successfully treated with retroperitoneal laparoscopic radical nephrectomy followed by a prompt resumption of the procedure. Various surgeries disturbing the abdominal wall integrity often disrupt the regular PD schedule, and using minimally invasive approaches is therefore an attractive therapeutic option. Our experience emphasizes the feasibility and safety of a retroperitoneal approach–based laparoscopic technique based on several empirical examples. However, systemic studies on this topic are obviously lacking, so we strongly recommend the accumulation of more cases similar to our own. Several surgical concerns that need to be dealt with among PD patients are also discussed.

Histotype differentiation of hypo-echoic renal tumors on CEUS: usefulness of enhancement homogeneity and intensity

PURPOSE

The purpose of this study is to evaluate qualitative and quantitative analysis of contrast-enhanced ultrasound (CEUS) in differential diagnoses of hypo-echoic renal tumor histotypes.

METHODS

Our study cohort comprised 103 clear cell renal cell carcinomas (ccRCCs), 24 papillary renal cell carcinomas (pRCCs), 28 chromophobe renal cell carcinomas (cRCCs), and 34 angiomyolipomas (AMLs), hypo-echoic on ultrasound, and imaged between January 2011 and December 2013. Enhancement homogeneity and tumor-to-cortex intensity ratio (TOC ratio) were retrospectively analyzed.

RESULTS

Overall, heterogeneous enhancement was more common in ccRCCs than AMLs, pRCCs, and cRCCs. TOC ratio showed the trend ccRCC > AML > pRCC = cRCC. Similar trends were seen in tumors <4 cm. Using heterogeneous enhancement or TOC ratio >107.5% to differentiate ccRCC from other histotypes, the sensitivity, specificity, positive and negative predictive values were 93.1%, 74.5%, 84.8%, and 87.5%, respectively. Tumors >4 cm exhibited considerable overlap in enhancement homogeneity among different histotypes. TOC ratios were similar between homo- and heterogeneously enhancing tumors for ccRCCs and for pRCCs and cRCCs, but higher in homogeneously enhancing than heterogeneously enhancing AMLs. In homo- and heterogeneously enhancing tumors, TOC ratios followed the trends ccRCCs > AMLs > pRCCs = cRCCs and ccRCCs > AMLs = pRCCs = cRCCs, respectively. With TOC ratio >105.81% and >72.37% to differentiate homo- and heterogeneously enhancing ccRCCs from other histotypes in tumors >4 cm with same enhancement homogeneity, the sensitivity, specificity, positive and negative predictive values were 70.0%, 85.7%, 70.0%, 85.7%, and 91.7%, 94.4%, 95.7%, 89.5%, respectively.

CONCLUSION

CEUS homogeneity and TOC ratio are helpful in differential diagnosis of hypo-echoic renal tumor histotypes. Diameter and enhancement homogeneity should be considered when deciding the diagnostic TOC ratio cutoff.

Use of DWI in the Differentiation of Renal Cortical Tumors

OBJECTIVE

The purpose of this study was to differentiate clear cell renal cell carcinoma (RCC) from other common renal cortical tumors by use of DWI.

MATERIALS AND METHODS

The study included 117 patients (mean age, 60 years) with 122 histopathologically confirmed renal cortical tumors who underwent 1.5-T MRI that included DWI before they underwent nephrectomy between 2006 and 2013. For each tumor, two radiologists independently evaluated apparent diffusion coefficient (ADC) values on the basis of a single ROI in a nonnecrotic area of the tumor and also by assessment of the whole tumor. The concordance correlation coefficient (CCC) was calculated to assess interreader agreement. The mean ADC values of clear cell RCC and every other tumor subtype were compared using an exact Wilcoxon rank sum test.

RESULTS

Interreader agreement was excellent and higher in whole-tumor assessment (CCC, 0.982) than in single-ROI analysis (CCC, 0.756). For both readers, ADC values for clear cell RCC found on single-ROI assessment (2.19 and 2.08 × 10(-3) mm(2)/s) and whole-tumor assessment (2.30 and 2.32 × 10(-3) mm(2)/s) were statistically significantly higher than those for chromophobe, papillary, or unclassified RCC (p < 0.05) but were similar to those for oncocytoma found on single-ROI assessment (2.14 and 2.32 × 10(-3) mm(2)/s) and whole-tumor assessment (2.38 and 2.24 × 10(-3) mm(2)/s). ADC values were also higher for clear cell RCC than for angiomyolipoma, but the difference was statistically significant only in whole-tumor assessment (p < 0.03).

CONCLUSION

ADC values were statistically significantly higher for clear cell RCC than for chromophobe, papillary, or unclassified RCC subtypes; however, differentiating clear cell RCC from oncocytoma by use of DWI remains especially challenging, because similar ADC values have been shown for these two tumor types.

Virtual Touch quantification using acoustic radiation force impulse (ARFI) technology for the evaluation of focal solid renal lesions: preliminary findings

AIM

To evaluate potential value of Virtual Touch quantification (VTQ) of acoustic radiation force impulse (ARFI) imaging for characterising focal solid renal lesions.

MATERIALS AND METHODS

Two independent operators performed 10 and five measurements of each lesion and adjacent renal cortex, respectively. Mean shear wave velocity (SWV) and shear wave velocity ratio (SWR) of histotypes were compared.

RESULTS

One hundred and ninety-seven renal lesions were evaluated, including 155 renal cell carcinomas (RCCs; 129 clear-cell RCCs [ccRCCs], 14 papillary RCCs [pRCCs], and 12 chromophobe RCCs [cRCCs]) and 42 angiomyolipomas (AMLs). The interoperator reproducibility of SWV of renal tumours and renal cortex were good (ICC=0.852, and 0.903, respectively). SWV of the renal cortex at a depth of <4 cm was significant higher than that at a depth of >4 cm. Regardless of the subtypes of RCC, SWV and SWR of RCCs differed significantly from those of AMLs (2.28±0.85 versus 1.98±0.85; 1.09±0.56 versus 0.78±0.34; p=0.045 and p<0.001, respectively). At cut-off points of SWV >1.87 m/s or SWR >0.84 to differentiate RCCs from AMLs, the sensitivity and specificity were 47.5%, 33.2% or 47.5%, 30.2%, respectively. When the subtypes of RCCs were taken into account, SWV and SWR of ccRCCs were significantly higher than those of pRCCs, cRCCs, and AMLs, while there was no significant difference among the latter. With SWV >1.98 m/s or SWR >0.80 as the cut-off point to differentiate ccRCCs from other renal tumours, the sensitivity and specificity were 69.8%, 65% or 76.8%, 73.4%, respectively.

CONCLUSION

The ARFI technique offers additional information regarding renal tumour elasticity with good reproducibility. SWV and SWR are potential biomarkers in this setting, helping to differentiate ccRCC from other renal tumour histotypes.

Qualitative and quantitative analysis with contrast-enhanced ultrasonography: diagnosis value in hypoechoic renal angiomyolipoma

Objective

To evaluate the value of enhancement features and quantitative parameters of contrast-enhanced ultrasonography (CEUS) in differentiating solid hypoechoic renal angiomyolipomas (AMLs) from clear cell renal cell carcinomas (ccRCCs).

Materials and Methods

We analyzed the enhancement features and quantitative parameters of CEUS in 174 hypoechoic renal masses (32 AMLs and 142 ccRCCs) included in the study.

Results

Centripetal enhancement pattern was more common in AMLs than in ccRCCs on CEUS (71.9% vs. 23.2%, p < 0.001). At peak enhancement, all AMLs showed homogeneous enhancement (100% in AML, 27.5% in ccRCCs; p < 0.001). Quantitative analysis showed no significant difference between rise time and time to peak. Tumor-to-cortex (TOC) enhancement ratio in AMLs was significantly lower than that in ccRCCs (p < 0.001). The criteria of centripetal enhancement and homogeneous peak enhancement together with TOC ratio < 91.0% used to differentiate hypoechoic AMLs from ccRCCs resulted in a sensitivity and specificity of 68.9% and 95.8%, respectively.

Conclusion

Both qualitative and quantitative analysis with CEUS are valuable in the differential diagnosis of hypoechoic renal AMLs from ccRCCs.

Open mini-flank partial nephrectomy: an essential contemporary operation

Secondary to the widespread use of the modern imaging techniques of computed tomography, magnetic resonance imaging, and ultrasound, 70% of renal tumors today are detected incidentally with a median tumor size of less than 4 cm. Twenty years ago, all renal tumors, regardless of size were treated with radical nephrectomy (RN). Elective partial nephrectomy (PN) has emerged as the treatment of choice for small renal tumors. The basis of this paradigm shift is three major factors: (1) cancer specific survival is equivalent for T1 tumors (7 cm or less) whether treated by PN or RN; (2) approximately 45% of renal tumors have indolent or benign pathology; and (3) PN prevents or delays the onset of chronic kidney disease, a condition associated with increased cardiovascular morbidity and mortality. Although PN can be technically demanding and associated with potential complications of bleeding, infection, and urinary fistula, the patient derived benefits of this operation far outweigh the risks. We have developed a "mini-flank" open surgical approach that is highly effective and, coupled with rapid recovery postoperative care pathways associated with a 2-day length of hospital stay.

Predicting the histology of small renal masses using preoperative dynamic contrast-enhanced magnetic resonance imaging

OBJECTIVE

To study whether magnetic resonance imaging can predict the histologic type of small renal cell carcinoma.

METHODS

Dynamic contrast-enhanced magnetic resonance imaging was performed in 63 patients with computed tomography- or ultrasonography-suspected small (≤ 4 cm) renal cell carcinoma from February 2008 to February 2010. Percentage signal intensity change, tumor-to-cortex enhancement index during precontrast phase, corticomedullary phase, and nephrogenic phase were investigated.

RESULTS

Among the 60 patients, 42 were proven to have clear cell renal cell carcinoma and 18 patients were proven to have non-clear cell renal cell carcinoma (10 patients with papillary renal cell carcinoma, 8 patients with chromophobe renal cell carcinoma). The percentage signal intensity change in the clear cell type was higher only in the corticomedullary phase (P = .002). The tumor-to-cortex enhancement index in the clear cell type was higher in the corticomedullary and nephrogenic phases (P = .007 and P = .041, respectively). The most valuable marker was percentage signal intensity change in the corticomedullary phase (area under the receiver operating characteristic curve 0.85). The cut-off value of percentage signal intensity change in the corticomedullary phase was 173%, and the sensitivity and specificity were 81% and 87.5%, respectively.

CONCLUSION

Dynamic contrast-enhanced magnetic resonance imaging could be useful for discriminating the clear cell type from non-clear cell type in small renal cell carcinoma with high sensitivity and specificity.

Renal cortical tumors: use of multiphasic contrast-enhanced MR imaging to differentiate benign and malignant histologic subtypes

PURPOSE

To investigate the use of quantitative multiphasic contrast material-enhanced magnetic resonance (MR) imaging in differentiating between common benign and malignant histologic subtypes of renal cortical tumors.

MATERIALS AND METHODS

The institutional review board waived informed consent and approved this retrospective HIPAA-compliant study of 138 patients who underwent preoperative contrast-enhanced MR imaging during the period of January 2004-December 2008. At surgery, 152 renal tumors were identified (77 clear cell, 22 papillary, 18 chromophobe, and 10 unclassified carcinomas; 16 oncocytomas; nine angiomyolipomas). Three readers independently identified and measured the most-enhanced area in each tumor and placed corresponding regions of interest in similar positions on images from the precontrast, corticomedullary, nephrographic, and excretory phases. The percentage change in signal intensity (%SI change) between precontrast imaging and each postcontrast phase was calculated. Interreader agreement was evaluated by using the overall concordance correlation coefficient (OCC). A linear mixed-effects model was used to estimate and compare the trajectories of the means of log %SI change across all phases between the six histologic subtypes.

RESULTS

Interreader agreement was substantial to almost perfect (OCC, 0.77-0.88). The %SI change differed significantly between clear cell carcinomas and papillary and chromophobe carcinomas in all phases of enhancement (P < .0001-.0120). In addition, %SI change was significantly higher in angiomyolipomas than in clear cell carcinomas, but only in the corticomedullary phase (P = .0231). Enhancement did not differ significantly between clear cell carcinoma and oncocytoma in any phase (P = .2081-.6000).

CONCLUSION

Quantitative multiphase contrast-enhanced MR imaging offers a widely available, reproducible method to characterize several histologic subtypes of renal cortical tumors, although it does not aid differentiation between clear cell carcinomas and oncocytomas.

Evaluation of renal masses with contrast-enhanced ultrasound: initial experience

OBJECTIVE

Nearly 25% of solid renal tumors are indolent cancer or benign and can be managed conservatively in selected patients. This prospective study was performed to determine whether preoperative IV microbubble contrast-enhanced ultrasound can be used to differentiate indolent and benign renal tumors from more aggressive clear cell carcinoma.

SUBJECTS AND METHODS

Thirty-four patients with renal tumors underwent preoperative gray-scale, color, power Doppler, and octafluoropropane microbubble IV contrast-enhanced ultrasound. Three blinded radiologists reading in consensus compared rate of contrast wash-in, grade and pattern of enhancement, and contrast washout compared with adjacent parenchyma. Contrast ultrasound findings were compared with surgical histopathologic findings for all patients.

RESULTS

The 34 patients had 23 clear cell carcinomas, three type 1 papillary carcinomas, one chromophobe carcinoma, one clear rare multilocular low-grade malignant tumor, two unclassified lesions, three oncocytomas, and one benign angiomyolipoma. The combination of heterogeneous lesion echotexture and delayed lesion washout had 85% positive predictive value, 43% negative predictive value, 48% sensitivity, and 82% specificity for predicting whether a lesion was conventional clear cell carcinoma or another tumor. Diminished lesion enhancement grade had 75% positive predictive value, 81% negative predictive value, 55% sensitivity, and 91% specificity for non-clear cell histologic features, either benign or low-grade malignant. Combining delayed washout with quantitative lesion peak intensity of at least 20% of kidney peak intensity had 91% positive predictive value, 40% negative predictive value, 63% sensitivity, and 80% specificity in the prediction of clear cell histologic features.

CONCLUSION

Ultrasound features of gray-scale heterogeneity, lesion washout, grade of contrast enhancement, and quantitative measure of peak intensity may be useful for differentiating clear cell carcinoma and non-clear cell renal tumors.

Misdiagnosis of clear cell renal cell carcinoma

Clear cell renal cell carcinoma (RCC) represents the most common histological subtype of malignant kidney tumors. Based on symptoms alone, clear cell RCC is indistinguishable from other histological classes of RCC unless the tumor is present in the context of an RCC syndrome. Histopathological examination is, therefore, important to accurately identify clear cell RCC. Clear cell RCCs have characteristic morphological criteria; these tumors can be easily identified upon typical presentation, but diagnosis can be challenging when tumor cell pattern is unusual or when availability of tissue samples is limited. In this Review, the clinical, radiological and pathological characteristics of clear cell RCCs are described, as well as the potential tumors that can be confused with clear cell RCC and need to be considered in the differential diagnoses. Finally, the importance of an accurate diagnosis is highlighted in the context of the increasing use of preoperative tissue sampling and the prevalence of clear cell tumors associated with hereditary syndromes, which could have different therapeutic and prognostic implications for patients and their families.

A nomogram for estimating the probability of ovarian cancer

OBJECTIVE

Accurate preoperative estimates of the probability of malignancy in women with adnexal masses are essential for ensuring optimal care. This study presents a new statistical model for combining predictive information and a graphic decision support tool for calculating risk of malignancy.

METHODS

The study included 153 women treated with definitive surgery for adnexal mass between 2001 and 2007 with preoperative ultrasound testing and a serum CA125. Multivariable logistic regression was used to develop a statistical model for estimating the probability of ovarian cancer as a function of age, ultrasound score, and CA125 value, with adjustments for nonlinear and interactive relationships.

RESULTS

A total of 20 cases of pathologically confirmed cancer (13 invasive malignancies, and 7 tumors of low malignant potential) were identified (20/153=13%). The model obtained excellent discrimination (ROC area=0.87), explained nearly half of the observed variation in the risk of malignancy (R²=0.43), and was well calibrated across the full range of malignancy probabilities. The model equation is represented in the form of a nomogram, which can be used to calculate preoperative probability of malignancy. At a 5% risk of malignancy threshold, the model has a sensitivity of 90% and a specificity of 73%.

CONCLUSIONS

Statistical models for estimating the probability of adnexal mass malignancy are substantially improved by including adjustments for non-linear relationships among key variables. A clinically relevant nomogram provides an objective tool to further aid clinicians in counseling patients and ensuring proper referral to surgical sub-specialists when indicated.

Imaging of renal cell carcinoma: state of the art and recent advances

BACKGROUND AND AIM

Renal cell carcinoma (RCC) is the 13th most common cancer worldwide and accounts for 4% of all adult malignancies. Herein the state of the art and recent advances in cross-sectional radiological imaging applied to RCC are reviewed, including ultrasonography, computed tomography, magnetic resonance imaging, and positron emission tomography.

METHODS

Literature search of peer-reviewed papers published by October 2010.

RESULTS

In front of more conventional and widespread imaging tools, such as ultrasonography and computed tomography, an array of newer and attractive radiological modalities are under investigation and show promise to improve our ability to noninvasively detect renal tumors and its recurrences, accurately assess the extent of the disease, and reliably evaluate treatment response, particularly in the era of antiangiogenetic therapy.

CONCLUSIONS

Recent major advances in radiological imaging techniques have considerably improved our ability to diagnose, stage and follow-up RCC. Further studies are needed to evaluate the potential of most recent and still investigational imaging tools.

Contrast-enhanced ultrasound using a time-intensity curve for the diagnosis of renal cell carcinoma

OBJECTIVE

• To evaluate the usefulness of contrast-enhanced ultrasound (CEUS) for the diagnosis of renal cell carcinoma by employing a time-intensity curve (TIC).

PATIENTS AND METHODS

• From May 2008 to October 2009, CEUS was performed prior to surgery in 30 patients with renal masses. • In all, 10 of the 30 patients had cystic renal masses. The final diagnoses of all patients were pathologically confirmed. Contrast enhancement as a function of time was measured in two (tumour or solid component of cystic lesions and normal parenchyma) regions of interest (ROI) and TICs were obtained. • The time to the contrast enhancement peak (TTP), intensity change from the baseline to peak (ΔI) and ΔI/TTP of the tumour and the normal parenchyma were measured from the TIC.

RESULTS

• Pathological diagnoses were renal cell carcinoma in 30 patients. • The TTP of the cancer was shorter than that of the normal parenchyma in all cases (6.0 ± 2.0 vs 10.4 ± 3.0 s; P < 0.0001). • The ΔI did not differ between the cancer and normal parenchyma [21.3 ± 5.9 vs 20.9 ± 7.0 decibels (db); P= 0.68]; the ΔI/TTP of the cancer was significantly higher than that of the normal parenchyma (3.9 ± 1.4 vs 2.2 ± 0.94 db/s; P < 0.0001). • TIC patterns of solid cancer and cystic cancer were very similar.

CONCLUSIONS

• An objective and quantitative diagnosis of renal cell carcinoma by CEUS using a second-generation ultrasound contrast agent can be made by employing a TIC. • The TIC patterns of solid and cystic cancers were very similar, despite their morphological and vascular differences. • CEUS using TIC is a promising tool in the diagnosis of cystic renal cancer.

Contrast enhanced ultrasound of renal masses

Contrast enhanced ultrasound (CEUS) has gained clinical importance over the last years for the characterization of hepatic masses. Its role in extrahepatic indications has been investigated repeatedly but has been less comprehensively studied. Currently more than 50% of renal masses are incidentally diagnosed, mostly by B-mode ultrasound. The method of choice for characterization of renal lesions is contrast enhanced computed tomography (CECT). In the case of cystic lesions CECT refers to the Bosniak classification for cystic lesions to assess the risk of malignant behavior. The majority of masses are renal cell carcinoma, but the exact proportion is controversial. Disadvantages of CECT are a significant risk for patients with impaired renal function, allergic reactions and hyperthyroidism due to iodinated contrast agents. Several studies concerning CEUS for the characterization of both solid and cystic renal lesions have been published, but prospective multicenter studies are missing, the presented data being mainly descriptive. The aim of the this manuscript is to review the current literature for CEUS in renal masses, to summarize the available data and focus on possible concepts for studies in the future.

Predicting the risk of perioperative transfusion for patients undergoing elective hepatectomy

OBJECTIVE

To develop 2 instruments that predict the probability of perioperative red blood cell transfusion in patients undergoing elective liver resection for primary and secondary tumors.

SUMMARY BACKGROUND DATA

Hepatic resection is the most effective treatment for several benign and malign conditions, but may be accompanied by substantial blood loss and the need for perioperative transfusions. While blood conservation strategies such as autologous blood donation, acute normovolemic hemodilution, or cell saver systems are available, they are economically efficient only if directed toward patients with a high risk of transfusion.

METHODS

Using preoperative data from 1204 consecutive patients who underwent liver resection between 1995 and 2000 at Memorial Sloan- Kettering Cancer Center, we modeled the probability of perioperative red blood cell transfusion. We used the resulting model, validated on an independent dataset (n = 555 patients), to develop 2 prediction instruments, a nomogram and a transfusion score, which can be easily implemented into clinical practice.

RESULTS

The planned number of liver segments resected, concomitant extrahepatic organ resection, a diagnosis of primary liver malignancy, as well as preoperative hemoglobin and platelets levels predicted the probability of perioperative red blood cell transfusion. The predictions of the model appeared accurate and with good discriminatory abilities, generating an area under the receiver operating characteristic curve of 0.71.

CONCLUSIONS

Preoperative factors can be combined into risk profiles to predict the likelihood of transfusion during or after elective liver resection. These predictions, easy to calculate in the frame of a nomogram or of a transfusion score, can be used to identify patients who are at high risk for red cell transfusions and therefore most likely to benefit from blood conservation techniques.

Predicting cancer-control outcomes in patients with renal cell carcinoma

PURPOSE OF REVIEW

An increasing number of models are becoming available for patients with either suspected or established renal cell carcinoma (RCC) of various stages. In this review, we propose a systematic approach to the assessment of the quantity of the existing predictive and prognostic models.

RECENT FINDINGS

Only one model was designed to distinguish between malignant or benign histology prior to nephrectomy and another tool attempts to discriminate between low-grade and high-grade histology. Four tools predict the natural history of RCC using preoperative tumor characteristics. Postnephrectomy recurrence can be predicted with four tools. Finally, mortality predictions can be quantified with 21 predictive tools. Although several of these tools are validated, formal tests were performed in surprisingly few such models.

SUMMARY

Multiple models can be applied to nephrectomy candidates, to patients treated with nephrectomy, or to individuals with metastatic RCC regardless of nephrectomy status. For newly diagnosed and untreated patients, these tools can guide the clinician with respect to treatment selection. For patients treated with nephrectomy, they can assess the risk of recurrence and/or mortality and can guide the type and frequency of follow-up considerations. Finally, for patients with metastatic RCC, the models can provide the best estimate of remaining life expectancy. Unfortunately, virtually no data are available to model the prognosis of patients subjected to surveillance or nonextirpative treatment models.

Molecular imaging of renal cell carcinoma

The recent identification of agents that have significantly influenced the therapy of clear cell renal carcinoma and the decreasing size of renal masses, usually detected serendipitously, have led to a resurgence in imaging for this condition. Although structural methods continue to be used routinely for identification of renal masses, functional and molecular techniques are showing considerable promise in their ability to characterize unique features of the renal cancer phenotype. This article discusses the evolving role of molecular imaging in the evaluation of renal cancer, including current and future applications.

How to build and interpret a nomogram for cancer prognosis

Nomograms are widely used for cancer prognosis, primarily because of their ability to reduce statistical predictive models into a single numerical estimate of the probability of an event, such as death or recurrence, that is tailored to the profile of an individual patient. User-friendly graphical interfaces for generating these estimates facilitate the use of nomograms during clinical encounters to inform clinical decision making. However, the statistical underpinnings of these models require careful scrutiny, and the degree of uncertainty surrounding the point estimates requires attention. This guide provides a nonstatistical audience with a methodological approach for building, interpreting, and using nomograms to estimate cancer prognosis or other health outcomes.

Imaging of kidney cancer

Advances in molecular genetics have expanded the understanding of renal cell tumors. Now it is understood that renal cortical tumors are a family of neoplasms with distinct cytogenetics and molecular defects, unique histopathologic features, and different malignant potentials. Imaging contributes to clinical management of patients with renal tumors in providing diagnostic information for tumor detection, characterization, staging, treatment planning, and follow-up.