Metastatic renal cell carcinoma: radiologic findings and assessment of response to targeted antiangiogenic therapy by using multidetector CT

Isolated Splenic Metastases from Renal Cell Carcinoma 11 Years after Surgery

Splenic metastases are rare and usually occur in cases of disseminated disease. We report a case of a patient who had isolated splenic metastases with a previous history of left nephrectomy due to a renal cell carcinoma 11 years before. The aim of this report is to describe the case and review the literature of isolated splenic metastases due to renal carcinoma. This case emphasizes the importance of considering splenic metastatic disease even after many years of diagnosis of renal cell carcinoma.

Renal Cell Carcinoma: the Oncologist Asks, Can PSMA PET/CT Answer?

PURPOSE OF REVIEW

To critically review the potential clinical applications of prostate-specific membrane antigen (PSMA) radioactive ligands in renal cell carcinoma (RCC).

RECENT FINDINGS

Radioactive probes targeting PSMA hold promise in several malignancies in addition to prostate cancer, owing to the expression of PSMA by tumor neovasculature. The majority of clear cell RCCs (ccRCC), the most malignant RCC subtype, express PSMA on tumor-associated neovasculature. The endothelium of less aggressive RCC subtypes is PSMA positive in a lower, but still significant percentage of cases. PSMA might therefore represent an interesting theragnostic target in RCC. The preliminary data available suggest a potential role for PSMA-targeting radiopharmaceuticals in complementing conventional imaging for staging ccRCC patients at risk of nodal involvement and oligometastatic disease. Additional applications of PSMA imaging may be the selection and the response assessment of patients receiving anti-angiogenic treatments. The effectiveness of PSMA-targeting radionuclide therapy should also be investigated.

Prognostic Impact of the Components of Progressive Disease on Survival After First-Line Tyrosine Kinase Inhibitor Therapy for Metastatic Renal Cell Carcinoma

BACKGROUND

According to the Response Evaluation Criteria in Solid Tumors (RECIST) classification, progressive disease (PD) is defined as target lesion growth (TLG), unequivocal non-target lesion growth (NTLG), or new lesion appearance (NLA). The prognostic impact of the components of PD in tyrosine kinase inhibitor (TKI) therapy for metastatic renal cell carcinoma (mRCC) remains unknown.

OBJECTIVE

We retrospectively evaluated the prognostic impact of these PD components on survival in patients with mRCC after first-line TKI therapy.

PATIENTS AND METHODS

Patients were divided into three groups (TLG, NTLG, and NLA) based on the components of PD. Progression-free survival (PFS) and overall survival (OS) after first-line TKI therapy were compared between groups using the Kaplan-Meier method and log-rank test. The predictive impact of the PD components was evaluated using multivariate analyses.

RESULTS

Among the 116 patients included, 80 (69.0%) had TLG, 18 (15.5%) NTLG, and 69 (58.6%) NLA. The mean PFS and OS were shorter for patients with TLG than those without TLG (PFS, 7.1 vs. 11.6 months, p = 0.0071; OS, 18.2 vs. 25.5 months, p = 0.0091). TLG was an independent predictor of PFS (hazard ratio [HR], 1.59; 95% confidence interval [CI], 1.02-2.51; p = 0.0395) and OS (HR, 1.67; 95% CI, 1.02-2.83; p = 0.040). NTLG and NLA were not associated with survival.

CONCLUSIONS

In this retrospective single-center study, patients with TLG had poor survival after first-line TKI therapy for mRCC. Thus, individual components of PD influence patient prognosis.

Improved identification of patients with oligometastatic clear cell renal cell carcinoma with PSMA-targeted 18F-DCFPyL PET/CT

OBJECTIVE

Complete surgical resection of metastatic sites has been shown to prolong survival in select patients with oligometastatic RCC. This treatment strategy is dependent upon the accurate characterization of a patient's extent of disease. The objective of this study was to explore the utility of PSMA-targeted ¹⁸F-DCFPyL PET/CT in patients with presumed oligometastatic clear cell RCC.

METHODS

This is a subset analysis of a prospective study in which patients with RCC were imaged with ¹⁸F-DCFPyL PET/CT (ClinicalTrials.gov identifier NCT02687139). In the present analysis, patients with oligometastatic clear cell RCC, defined as ≤ 3 metastatic lesions on conventional imaging, were evaluated. ¹⁸F-DCFPyL PET/CT scans were reviewed for sites of disease and compared to conventional imaging.

RESULTS

The final cohort included 14 patients with oligometastatic clear cell RCC. Conventional imaging revealed 21 metastatic lesions and 3 primary tumors. ¹⁸F-DCFPyL PET/CT detected 29 sites of metastatic disease and 3 primary tumors. Of the 21 metastatic lesions detected on conventional imaging, 17 (81.0%) had radiotracer uptake. Additionally, all 3 primary tumors had radiotracer uptake. In 4 (28.6%) patients a total of 12 more lesions were identified on ¹⁸F-DCFPyL PET/CT than conventional imaging. Notably, 3 (21.4%) patients were no longer considered oligometastatic. The detection rates of conventional imaging and ¹⁸F-DCFPyL PET/CT for identifying sites of disease were 66.7% and 88.9%, respectively.

CONCLUSIONS

PSMA-targeted PET/CT appears to aid in the identification of patients with oligometastatic clear cell RCC. If borne out in future studies, this suggests that PSMA-targeted imaging has the potential to help select candidates for metastasis-directed therapy.

Right ventricular metastasis from unclassified Renal Cell Carcinoma

Background:

Cardiac metastasis of unclassified renal cell carcinoma (RCC) subtype is very rare, and even more so is an isolated right ventricular (RV) metastasis without vena cava extension or right atrial involvement. To the best of our knowledge, this is the first report of a cardiac metastasis of an unclassified RCC (an aggressive RCC) without vena cava extension.

Case Presentation:

A 61-year-old African American male with past medical history of hypertension and schizophrenia presented to the emergency room following 2 episodes of syncope and 3-month history of progressive neck mass. CT scan of neck, abdomen and pelvis showed bulky left cervical, supraclavicular and axillary lymph node, mass in anterior aspect of heart, and multiple solid left renal masses and probable right renal mass. Echocardiogram revealed a large RV mass with deformation of the RV free wall suggesting malignant growth. Core biopsy of the right superficial gluteal mass revealed a metastatic poorly differentiated carcinoma of likely renal origin, with a possibility of an unclassified RCC. Due to the extent and burden of metastasis, patient and family members agreed to conservative management and evaluation for hospice care.

Conclusion:

Cardiac metastasis of unclassified RCC is rare, and even more so is an isolated RV metastasis without vena cava extension or right atrial involvement, and the present case, to the best of knowledge is the first of such rare presentation.

Comparative Effectiveness of Tumor Response Assessment Methods: Standard of Care Versus Computer-Assisted Response Evaluation

PURPOSE

To compare the effectiveness of metastatic tumor response evaluation with computed tomography using computer-assisted versus manual methods.

MATERIALS AND METHODS

In this institutional review board-approved, Health Insurance Portability and Accountability Act-compliant retrospective study, 11 readers from 10 different institutions independently categorized tumor response according to three different therapeutic response criteria by using paired baseline and initial post-therapy computed tomography studies from 20 randomly selected patients with metastatic renal cell carcinoma who were treated with sunitinib as part of a completed phase III multi-institutional study. Images were evaluated with a manual tumor response evaluation method (standard of care) and with computer-assisted response evaluation (CARE) that included stepwise guidance, interactive error identification and correction methods, automated tumor metric extraction, calculations, response categorization, and data and image archiving. A crossover design, patient randomization, and 2-week washout period were used to reduce recall bias. Comparative effectiveness metrics included error rate and mean patient evaluation time.

RESULTS

The standard-of-care method, on average, was associated with one or more errors in 30.5% (6.1 of 20) of patients, whereas CARE had a 0.0% (0.0 of 20) error rate ( P < .001). The most common errors were related to data transfer and arithmetic calculation. In patients with errors, the median number of error types was 1 (range, 1 to 3). Mean patient evaluation time with CARE was twice as fast as the standard-of-care method (6.4 minutes v 13.1 minutes; P < .001).

CONCLUSION

CARE reduced errors and time of evaluation, which indicated better overall effectiveness than manual tumor response evaluation methods that are the current standard of care.

Impact of Variability in Portal Venous Phase Acquisition Timing in Tumor Density Measurement and Treatment Response Assessment: Metastatic Colorectal Cancer as a Paradigm

PURPOSE

New response patterns to anticancer drugs have led tumor size-based response criteria to shift to also include density measurements. Choi criteria, for instance, categorize antiangiogenic therapy response as a decrease in tumor density > 15% at the portal venous phase (PVP). We studied the effect that PVP timing has on measurement of the density of liver metastases (LM) from colorectal cancer (CRC).

METHODS

Pretreatment PVP computed tomography images from 291 patients with LM-CRC from the CRYSTAL trial (Cetuximab Combined With Irinotecan in First-Line Therapy for Metastatic Colorectal Cancer; ClinicalTrials.gov identifier: NCT00154102) were included. Four radiologists independently scored the scans' timing according to a three-point scoring system: early, optimal, late PVP. Using this, we developed, by machine learning, a proprietary computer-aided quality-control algorithm to grade PVP timing. The reference standard was a computer-refined consensus. For each patient, we contoured target liver lesions and calculated their mean density.

RESULTS

Contrast-product administration data were not recorded in the digital imaging and communications in medicine headers for injection volume (94%), type (93%), and route (76%). The PVP timing was early, optimal, and late in 52, 194, and 45 patients, respectively. The mean (95% CI) accuracy of the radiologists for detection of optimal PVP timing was 81.7% (78.3 to 85.2) and was outperformed by the 88.6% (84.8 to 92.4) computer accuracy. The mean ± standard deviation of LM-CRC density was 68 ± 15 Hounsfield units (HU) overall and 59.5 ± 14.9 HU, 71.4 ± 14.1 HU, 62.4 ± 12.5 HU at early, optimal, and late PVP timing, respectively. LM-CRC density was thus decreased at nonoptimal PVP timing by 14.8%: 16.7% at early PVP ( P < .001) and 12.6% at late PVP ( P < .001).

CONCLUSION

Nonoptimal PVP timing should be identified because it significantly decreased tumor density by 14.8%. Our computer-aided quality-control system outperformed the accuracy, reproducibility, and speed of radiologists' visual scoring. PVP-timing scoring could improve the extraction of tumor quantitative imaging biomarkers and the monitoring of anticancer therapy efficacy at the patient and clinical trial levels.

Current Challenges in Diagnosis and Assessment of the Response of Locally Advanced and Metastatic Renal Cell Carcinoma

Locally advanced and metastatic renal cell carcinoma (RCC) present a specific set of challenges to the radiologist. The detection of metastatic disease is confounded by the ability of RCC to metastasize to virtually any part of the human body long after surgical resection of the primary tumor. This includes sites not commonly included in routine surveillance, which come to light after the patient becomes symptomatic. In the assessment of treatment response, the phenomenon of tumor heterogeneity, where clone selection through systemic therapy drives the growth of potentially more aggressive phenotypes, can result in oligoprogression despite overall disease control. Finally, advances in therapy have resulted in the development of immuno-oncologic agents that may result in changes that are not adequately evaluated with conventional size-based response criteria and may even be misinterpreted as progression. This article reviews the common challenges a radiologist may encounter in the evaluation of patients with locally advanced and metastatic RCC. ^©RSNA, 2019.

Volume Computed Tomography Perfusion Imaging: Evaluation of the Significance in Oncologic Follow-up of Metastasizing Renal Cell Carcinoma in the Early Period of Targeted Therapy - Preliminary Results

INTRODUCTION

The aim of this study was to assess the significance of volume computed tomography perfusion imaging of metastasizing renal cell carcinoma (mRCC) in the early period after the initiation of targeted therapy.

METHODS

Blood flow (BF), blood volume, and clearance (CL) were calculated in 10 patients with histologically verified mRCC before and 1 month after initiation of targeted therapy using compartmental analysis algorithms. In addition, the longest diameter of tumor was measured for both time points and compared. Correlation test was performed between perfusion parameters and size changes with time to progression (TTP).

RESULTS

Blood flow and CL were significantly lower after therapy initiation, whereas blood volume and the long diameter remained unchanged. Median values before and after 4 weeks of therapy were 144.2 versus 99.4 mL/min/100 mL for BF (P = 0.009) and 115.5 versus 46.8 mL/min/100 mL for CL (P = 0.007). Changes in BF and CL showed very strong negative correlation with TTP (r = -0.838, P = 0.009 and r = -0.826, P = 0.011, respectively).

CONCLUSIONS

Our preliminary study results indicate that volume computed tomography perfusion may assess targeted therapy response of mRCC earlier than the currently used Response Evaluation Criteria in Solid Tumors. In addition, changes in BF and CL may be a promising parameter for prediction of TTP.

Inconsistent Detection of Sites of Metastatic Non-Clear Cell Renal Cell Carcinoma with PSMA-Targeted [18F]DCFPyL PET/CT

PURPOSE

To investigate the utility of prostate-specific membrane antigen (PSMA)-targeted [¹⁸F]DCFPyL positron emission tomography (PET)/X-ray computed tomography (CT) imaging for the detection of sites of disease in patients with metastatic non-clear cell renal cell carcinoma (RCC).

PROCEDURES

Eight patients with metastatic non-clear cell RCC underwent imaging with PSMA-targeted [¹⁸F]DCFPyL PET/CT. Imaged RCC histologic subtypes included papillary RCC (n = 3), chromophobe RCC (n = 2), unclassified RCC (n = 2), and Xp11 translocation RCC (n = 1). Using comparison to conventional CT and/or magnetic resonance imaging as reference, two radiologists with expertise in nuclear medicine identified putative sites of disease on [¹⁸F]DCFPyL PET/CT and classified each lesion as having no radiotracer uptake, equivocal uptake, or definitive uptake.

RESUTS

In total, 73 metastatic sites and 3 primary tumors compatible with sites of non-clear cell RCC were identified on conventional imaging. Metastatic sites of disease included lymph nodes (n = 40), venous thrombi (n = 3), pulmonary nodules (n = 10), bone lesions (n = 15), brain lesions (n = 3), and retroperitoneal masses (n = 2). Only 10 of the 73 lesions (13.7 %) were classified as having definitive radiotracer uptake (median SUV_max = 3.25, range = 1.2-9.5), 14 lesions (19.2 %) had equivocal uptake (median SUV_max = 2.85, range = 0.5-6.5), and 49 lesions (67.1 %) had no definitive uptake above background (median SUV_max = 1.7, range = 0.2-3.0). The three primary renal tumors demonstrated lower radiotracer avidity relative to surrounding normal renal parenchyma.

CONCLUSIONS

A small proportion of sites of non-clear cell RCC showed uptake of the PSMA-targeted radiotracer [¹⁸F]DCFPyL. Unlike for clear cell RCC, the results of this study indicate that PSMA-based PET is not appropriate for imaging other RCC subtypes.

Components of Radiologic Progressive Disease Defined by RECIST 1.1 in Patients with Metastatic Clear Cell Renal Cell Carcinoma

Background Progression-free survival (PFS) determined by Response Evaluation Criteria in Solid Tumors version 1.1 (RECIST 1.1) is the reference standard to assess efficacy of treatments in patients with clear cell renal cell carcinoma. Purpose To assess the most common components of radiologic progressive disease as defined by RECIST 1.1 in patients with clear cell renal cell carcinoma and how the progression events impact PFS. Materials and Methods This secondary analysis of the phase III METEOR trial conducted between 2013 and 2014 included patients with metastatic clear cell renal cell carcinoma, with at least one target lesion at baseline and one follow-up time point, who were determined according to RECIST 1.1 to have progressive disease. A chest, abdominal, and pelvic scan were acquired at each time point. Kruskal-Wallis analysis was used to test differences in median PFS among the RECIST 1.1 progression events. The Holm-Bonferroni method was used to compare the median PFS of the progression events for the family-wise error rate of 5% to adjust P values for multiple comparisons. Results Of the 395 patients (296 men, 98 women, and one patient with sex not reported; mean age, 61 years ± 10), 73 (18.5%) had progression due to non-target disease, 105 (26.6%) had new lesions, and 126 (31.9%) had progression of target lesions (defined by an increase in the sum of diameters). Patients with progression of non-target disease and those with new lesions had shorter PFS than patients with progression defined by the target lesions (median PFS, 2.8 months [95% confidence interval {CI}: 1.9 months, 3.7 months] and 3.6 months [95% CI: 3.3 months, 3.7 months] vs 5.4 months [95% CI: 5.0 months, 5.5 months], respectively [P < .01]). Conclusion The most common causes for radiologic progression of renal cell carcinoma were based on non-target disease and new lesions rather than change in target lesions, despite this being considered uncommon in the Response Evaluation Criteria in Solid Tumors version 1.1 literature. © RSNA, 2019 See also the editorial by Kuhl in this issue.

Early Changes in CT Perfusion Parameters: Primary Renal Carcinoma Versus Metastases After Treatment with Targeted Therapy

Computed tomography (CT) perfusion is a novel imaging method to determine tumor perfusion using a low-dose CT technique to measure iodine concentration at multiple time points. We determined if early changes in perfusion differ between primary renal tumors and metastatic tumor sites in patients with renal cell carcinoma (RCC) receiving targeted anti-angiogenic therapy. A total of 10 patients with advanced RCC underwent a CT perfusion scan at treatment baseline and at one week after initiating treatment. Perfusion measurements included blood volume (BV), blood flow (BF), and flow extraction product (FEP) in a total of 13 lesions (six primary RCC tumors, seven RCC metastases). Changes between baseline and week 1 were compared between tumor locations: primary kidney tumors vs metastases. Metastatic lesions had a greater decrease in BF (average BF difference ± standard deviation (SD): −75.0 mL/100 mL/min ± 81) compared to primary kidney masses (−25.5 mL/100 mL/min ± 35). Metastatic tumors had a wider variation of change in BF, BV and FEP measures compared to primary renal tumors. Tumor diameters showed little change after one week, but early perfusion changes are evident, especially in metastatic lesions compared to primary lesions. Future studies are needed to determine if these changes can predict which patients are benefiting from targeted therapy.

Thoracic Manifestations of Genitourinary Neoplasms and Treatment-related Complications

Genitourinary (GU) malignancies are a diverse group of common and uncommon neoplasms that may be associated with significant mortality. Metastases from GU neoplasms are frequently encountered in the chest, and virtually all thoracic structures can be involved. Although the most common imaging manifestations include hematogenous dissemination manifesting with peripheral predominant bilateral pulmonary nodules and lymphatic metastases manifesting with mediastinal and hilar lymphadenopathy, some GU malignancies exhibit unique features. We review the general patterns, pathways, and thoracic imaging features of renal, adrenal, urothelial, prostatic, and testicular metastatic neoplasms, as well as provide a discussion of treatment-related complications that might manifest in the chest. Detailed reporting of these patterns will allow the imager to assist the referring clinicians and surgeons in accurate determination of the stage, prognosis, and treatment options available for the patient. Awareness of specific treatment-related complications further allows the imager to enhance patient safety through accurate and timely reporting of potentially life-threatening consequences of therapies.

Is Chest Computed Tomography Always Necessary Following Nephrectomy for Renal Cell Carcinoma? A Pilot Study in Single Tertiary Institution

PURPOSE

We evaluated patterns of thoracic recurrence from renal cell carcinoma (RCC) following nephrectomy as a pilot study.

METHODS

Data of consecutive 39 patients who had recurrent RCC in the abdomen or thorax following curative nephrectomy were evaluated. Recurrence sites were analyzed with abdomen and chest computed tomography (CT), or positron emission tomography/CT. All patients had no metastasis before initial nephrectomy. Recurrence was classified into 3 types according to the site of initially detected recurrence: (a) abdomen-only type, (b) abdomen and thorax type, and (c) thorax-only type. Vertebral level of recurrence site in the thorax-only level was investigated. University of California Los Angeles-Integrated Staging System was utilized for risk stratification (eg, low, intermediate, and high-risk).

RESULTS

Rate of intermediate or high risk was 89.7% (37/39). Rate of thoracic recurrence, regardless of concurrent abdominal recurrence, was 71.8% (28/39). Rate of thorax-only type was 53.8% (21/39). In thorax-only type, median vertebral level of recurrence site was T10 (range, T3-T12), and no patient with low risk had metastasis above the T10 level alone. In intermediate or high risk, 89.2% (33/37) had at least a recurrent lesion at the level of T7 or lower.

CONCLUSIONS

In low-risk patients, upper thoracic recurrence alone may be very rare after curative surgery. In majority of intermediate- or high-risk patients, initial recurrence may occur in the abdomen or lower thorax, which indicates abdomen CT covering T7 level may be an effective tool for postoperative follow-up in RCC.

Differentiation of pancreatic neuroendocrine tumors from pancreas renal cell carcinoma metastases on CT using qualitative and quantitative features

PURPOSE

To assess qualitative and quantitative imaging features on enhanced CT that may differentiate pancreatic neuroendocrine tumors (PNETs) from pancreatic renal cell carcinoma (RCC) metastases.

METHODS

This IRB-approved multi-center retrospective case-control study compared 43 resected PNETs and 28 resected RCC metastases with pre-operative enhanced CT identified consecutively between 2003 and 2017. Two blinded radiologists (R1/R2) independently assessed tumor location, attenuation (relative to pancreas), composition (solid/cystic/mixed), homogeneity (homogeneous/heterogeneous), calcification, multiplicity, and for main pancreatic duct (MPD) dilation. Tumors were segmented for quantitative texture analysis. Data were analyzed with Chi square, logistic regression, and receiver operating characteristic (ROC). Inter-observer agreement was assessed (Cohen's kappa).

RESULTS

There was no difference in age, gender, location, attenuation, or composition (P > 0.05) between groups. PNETs were larger than RCC metastases (37 ± 23 mm vs. 26 ± 21 mm, P = 0.038), more frequently solitary (P < 0.001), subjectively more heterogeneous (P = 0.033/0.144, R1/R2), and associated with calcification (P = 0.002/0.004) and MPD dilation (P = 0.025/0.006). Agreement for subjective features was moderate-to-almost perfect (K = 0.4879-0.9481). Quantitative texture analysis showed higher entropy in PNETs (6.32 ± 0.49 versus 5.96 ± 0.53; P = 0.004) with no difference in other features studied (P > 0.05). Entropy had ROC area under the curve for diagnosis of PNET of 0.77 ± 0.06, with optimal sensitivity/specificity of 71.4/79.1%.

CONCLUSIONS

Compared to pancreatic RCC metastases, PNETs are larger, more frequently solitary, contain calcification, show MPD dilation, and are subjectively and quantitatively more heterogeneous tumors.

mTOR inhibitor and bone-targeted drugs break the vicious cycle between clear-cell renal carcinoma and osteoclasts in an in vitro co-culture model

The skeleton is one of the most common sites of metastatic spread from advanced clear-cell renal carcinoma (ccRCC). Most of the bone lesions observed in RCC patients are classified as osteolytic, causing severe pain and morbidity due to pathological bone destruction. Nowadays, it is well known that cancer induced bone loss in lytic metastasis is caused by the triggering of a vicious cycle between cancer and bone resident cells that leads to an imbalance between bone formation and degradation. Targeting the mammalian target of rapamycin (mTOR) is an efficient treatment option for metastatic renal carcinoma patients. Moreover, bone targeted therapy could benefit bone metastatic cancer patients caused by advanced RCC. However, more data is needed to support the hypothesis of the beneficial effect of a combined therapy. The aim of this work is to investigate the effect of targeting mTOR and the sequential combination with bone targeted therapy as a strategy to break the vicious cycle between ccRCC cells and osteoclasts. A previously optimized fully human co-culture model is used to mimic the crosstalk between Caki-2 cells (ccRCC) and osteoclasts. Cells are treated at fixed timing with everolimus, zoledronic acid and denosumab as single or sequential combined treatment. We show that Caki-2 cells can induce osteoclast cells differentiation from isolated human monocytes, as demonstrated by specific tartrate-resistant acid phosphatase (TRAP) staining and f-actin ring formation, in a statistically significant manner. Moreover, differentiated osteoclasts proved to be functionally active by pit formation assay. Caki-2 cells co-cultured with osteoclasts acquire a more aggressive phenotype based on gene expression analysis. Interestingly, the sequential combined treatment of everolimus and zoledronic acid is the most effective in the inhibition of both Caki-2 cells survival and osteoclastogenic potential, making it an effective strategy to inhibit the vicious cycle of bone metastasis. At preclinical level, this observation confirms the value of our co-culture model as a useful tool to mimic the bone microenvironment and to assess drug sensitivity in vitro. A better understanding of the molecular mechanisms involved in tumor-bone cells crosstalk will be investigated next.

18F-FDG PET/CT detects Metastatic Renal Cell Carcinoma Masquerading as Primary Breast Malignancy

We present the case of a 36-year-old woman who underwent ¹⁸F-FDG PET/CT with suspicion of a primary breast malignancy. However, PET/CT detected an occult renal cell carcinoma with metastases to the thyroid, breast, lungs and lymph nodes. Thyroid and breast metastases are atypical metastatic sites of renal cell carcinoma. Breast metastases from extra mammary tissue are extremely rare, more so from renal cell carcinoma. Histopathologic confirmation of the breast lesions is imperative to avoid unnecessary mastectomy and imaging can help in raising the suspicion of metastatic involvement versus primary breast malignancy.

Life-threatening Hyperkalemia Associated with Axitinib Treatment in Patients with Recurrent Renal Carcinoma

Axitinib has emerged as a promising antineoplastic agent for the treatment of advanced renal cell carcinoma. Although the administration of axitinib was well-tolerated in clinical trials, the real-world safety and tolerability remain unverified. We herein report a patient with metastatic renal cell carcinoma who suddenly developed life-threatening hyperkalemia following the initiation of axitinib treatment. Although hyperkalemia has been reported with an incidence of <10%, acute severe hyperkalemia may be a considerably critical adverse event of axitinib therapy, especially in patients with risk factors for hyperkalemia. An abundance of caution for unusual and unpredictable toxicities is warranted when using axitinib.

Assessing lymph node status in patients with kidney cancer

Accurate detection of lymph node involvement on pre-operative imaging in patients diagnosed with renal cell carcinoma (RCC) is critical for determination of disease stage, one of the most significant prognostic factors in RCC. The presence of lymph node involvement in RCC doubles a patient’s risk of distant metastasis and significantly reduces their 5-year survival. Currently, lymph node involvement in patients with RCC is evaluated with numerous modalities, with rapid advancements occurring across these modalities. The purpose of this study was to evaluate the advantages and disadvantages of each modality and utilize sensitivities and specificities to determine the highest performing modalities for accurate lymph node involvement in renal cancer. A comprehensive computer-based literature search of full-length original research English language studies of human subjects with biopsy-proven RCC was performed to evaluate publications on the diagnostic performance of color Doppler sonography (CDS), magnetic resonance imaging (MRI), lymphotrophic nanoparticle enhanced MRI (LNMRI), multidetector-row computed tomography (MDCT), F-fluoro-2-deoxyglucose positron emission tomography (FDG-PET), and PET/CT for evaluation of lymph node status in kidney cancers in articles that were published prior to May 2018. Limited studies were available for evaluating CDS performance for determination of lymph node involvement in renal cancer. While CT is the most common modality for nodal staging, due to its availability and relatively low expense, it did not demonstrate the highest performance of the modalities examined for determination of lymph node status in patients with RCC. Of the modalities examined, MRI demonstrated the highest sensitivity (92–95.7%) for detection of lymph node involvement in RCC. Studies of lymph node involvement in RCC using both MRI and CT indicated that using the current diameter criteria (greater than 1 cm) for determination of positive lymph nodes should be re-evaluated as micro-metastases are frequently overlooked. Studies evaluating lymph node involvement with FDG-PET had the highest specificity (100%), indicating FDG-PET is the preferred modality for confirming lymph node involvement and extent of involvement. However, due to the low sensitivity of FDG-PET, clinicians should be skeptical of negative reports of lymph node involvement in RCC patients. Further studies examining determination of lymph node involvement in renal cancer across modalities are greatly needed, current literature suggests utilizing a combination of MRI and FDG-PET may offer the highest accuracy.

Imaging response assessment of immunotherapy in patients with renal cell and urothelial carcinoma

PURPOSE OF REVIEW

Recent advances in anticancer immunotherapy have revolutionized the treatment of metastatic renal cell (RCC) and urothelial carcinoma. In this review, we discuss the mechanisms of action of these new therapeutic approaches, explicate the common adverse events, and highlight different imaging-based response criteria.

RECENT FINDINGS

The recent introduction of immune-checkpoint inhibitors led to substantial advances in therapy of metastatic RCC and urothelial carcinoma. Because of the distinct effector mechanisms of these new substances, atypical response patterns such as transient enlargements of tumor lesions, appearance of new lesions after therapy, no measurable decrease in tumor size, or delayed responses are observed in medical imaging studies. This indicates that the established imaging-based response assessment according to the Response Evaluation Criteria in Solid Tumors (RECIST) guidelines has shortcomings to comprehensively evaluate treatment effects.

SUMMARY

While monitoring response to immunotherapy still relies on RECIST criteria, immune-related response criteria have been established to better address the imaging changes occurring under immunotherapy. Further studies with long-term follow-up are needed to properly identify and predict response after treatment beyond progression. Because of the expanding clinical use of immune checkpoint inhibitors, radiologists, urologist, and oncologists should be familiar with common imaging findings under this respective therapy.

Use of Dual-Energy Computed Tomography for Evaluation of Genitourinary Diseases

Since its clinical inception a decade ago, dual-energy computed tomography has expanded the array of computed tomography imaging tools available to the practicing abdominal radiologist. Of note, diagnostic solutions for imaging-based evaluation of genitourinary diseases, foremost kidney calculi and renal tumors characterization, represent the apogee applications of dual-energy computed tomography in abdominal imaging. This article reviews clinical applications of dual-energy computed tomography for the assessment of genitourinary diseases.

Endobronchial ultrasound-guided transbronchial needle aspiration in the diagnosis of mediastinal metastases of clear cell renal cell carcinoma

Evaluation of mediastinal lymphadenopathy in patients with a previous diagnosis of renal cell carcinoma (RCC) is critical for the determination of further treatment. A minimally invasive method of cytology sampling of mediastinal lymph nodes using endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) has emerged as a useful tool in diagnosis. Between January 2010 and April 2018, we performed 1744 EBUS-TBNA studies of mediastinal and hilar lymph nodes for a variety of clinical indications including mediastinal malignancy. Sixteen patients (93.7% males, mean age 59.1 years, range 44-81 years) were diagnosed by cytological and cell block study to have metastatic clear cell RCC. Twelve patients had been diagnosed with clear cell RCC in the past (mean 39 months, range 4-89 months) while in four, the tumor was primarily diagnosed in the staging phase on the basis of EBUS-TBNA. The EBUS features of the mediastinal nodal masses included increase of size (mean 2.5 cm, range 1.6-3.8 cm), irregular, inhomogeneous, hypervascular, and hyperechoic echotexture. EBUS-TBNA is a procedure safe and effective for evaluating mediastinal lymphadenopathy in patients with clear cell RCC. Immunohistochemistry in the cell block is decisive for proper diagnosis. The cytologist plays a key role in the diagnosis of metastatic clear cell RCC due to the treatment implications that this neoplasm encompasses.

Recurrent renal cell carcinoma following nephrectomy and ablation therapy: Radiology perspective

Renal cell carcinoma (RCC) is the most common renal malignancy, accounting for approximately 2% of adult malignancies and 4% of new cancer cases in the United States every year. Imaging guided ablative therapy, including radiofrequency (RF) ablation, cryotherapy and microwave has gained popularity over the last decade in treatment of small tumors. Antiangiogenic therapy has set itself to be the standard of care for many patients with metastasis these days. With hope for more research, survival rates of metastatic RCC may increase from a current 2-year survival rate of approximately 20%. Variation in imaging surveillance protocol in terms of frequency, modality, and duration is noted among guidelines developed by several organizations. In this review article, we will discuss follow-up imaging protocols, patterns of RCC recurrence following different modalities of treatment, imaging appearance, as well as usual and unusual sites of metastatic disease.

Morphoproteomics and biomedical analytics confirm the mTORC2/Akt pathway as a resistance signature and activated ERK and STAT3 as concomitant prosurvival/antiapoptotic pathways in metastatic renal cell carcinoma (RCC) progressing on rapalogs: pathogenesis and therapeutic options

Background

It has been proposed that resistance to rapalog therapies in renal cell carcinoma (RCC) is due to adaptive switching from mammalian target of rapamycin complex 1 (mTORC1) to mTORC2.

Objective

To combine phosphoprotein staining and applied biomedical analytics to investigate resistance signatures in patients with metastatic RCC progressing on rapalog therapies.

Design

We applied morphoproteomic analysis to biopsy specimens from nine patients with metastatic RCC who continued to show clinical progression of their tumors while being treated with a rapalog.

Results

In patients who were on temsirolimus or everolimus at the time of biopsy, a moderate to strong expression of phosphorylated (p)-mTOR (Ser 2448) in the nuclear compartment with concomitant expression of p-Akt (Ser 473) confirmed the mTORC2 pathway. Concomitant moderate to strong nuclear expression of p-ERK 1/2 (Thr202/Tyr204) and p-STAT3 (Tyr705) was confirmed. Histopathologic changes of hypoxic-type coagulative necrosis in 5 cases as well as identification of insulin-like growth factor-1 receptor (IGF-1R) expression and histone methyltransferase EZH2 in all tumors studied suggested that hypoxia also contributed to the resistance signature. Biomedical analytics provided insight into therapeutic options that could target such adaptive and pathogenetic mechanisms.

Conclusions

Morphoproteomics and biomedical analytics confirm mTORC2/Akt as a resistance signature to rapalog therapy in metastatic RCC and demonstrate activation of the prosurvival ERK and STAT3 pathways and involvement of hypoxic pathways that contribute to pathogenesis of such adaptive resistance. These results highlight the need for a novel combinatorial therapeutic approach in metastatic RCC progressing on rapalogs.

Sternal resection of a solitary renal cell carcinoma metastasis: a case report and a literature review

BACKGROUND

Renal cell carcinoma (RCC) may be metastatic, although solitary sternal metastasis of RCC is a rare medical condition. Here we report an unusual case of a 63-year-old male with a solitary sternal metastasis as an initial presentation of clear-cell renal cell carcinoma.

MATERIALS AND METHODS

A 63-year-old male presented with a small sternal mass. Chest computer tomography (CT) and a biopsy from the sternal tumour were performed. Histopathological examination revealed the diagnosis of renal clear cell carcinoma metastasis to the sternal bone. On the basis of a subsequently performed abdominal CT the patient was confirmed with a suspicion of a left renal lower pole tumour. Treatment with sunitinib was initiated. Due to the limited response and a growing sternal mass, the patient was admitted to the National Cancer Institute after two cycles of sunitinib therapy. Open left partial nephrectomy was performed followed by the resection of the sternal metastasis two months later. The chest wall was reconstructed with polypropylene mesh combined with transversal rectus abdominis musculocutaneous flap.

RESULTS

The postoperative course after the partial nephrectomy was uneventful. The postoperative course of metastasectomy complicated with the right pneumothorax which was successfully treated by insertion of a chest tube. Bleeding from the upper digestive tract also occurred on the seventh postoperative day but was successfully controlled by haemostasis with three 20 ml endoscopic injections of 1:10,000 solution of epinephrine. The patient had been followed up after the surgery for 30 months with biannual chest and abdominal CT scans that showed neither local nor distant recurrence of the disease.

CONCLUSIONS

Radical surgical treatment of a solitary renal clear cell carcinoma metastasis may offer the best cancer-specific outcomes and improve the quality of life in some patients.

Renal cell carcinoma metastatic to the maxillary gingiva: A case report and review of the literature

Tumor metastasis to the oral cavity is rare and is usually an indication of late-stage disease and poor prognosis. While, there are reports of renal cell carcinoma (RCC) metastatic to oral cavity, vast majority of them are to the jaw. Herein, we present a case of a 78-year-old woman with RCC metastasis limited to the oral soft tissue without any bone involvement. As the lesion solely involved maxillary gingiva, it clinically mimicked that of a pyogenic granuloma, which is a reactive, nonneoplastic condition. This case was further complicated as the patient was unaware of primary cancer and appeared to be in good physical health. Her oral metastasis marked the initial manifestation of an otherwise silent primary renal cancer.

Imaging features of solid renal masses

The widespread use of abdominal imaging techniques has increased the detection of solid renal masses over the past years. Imaging plays a crucial role in the management and surveillance and in determining which lesions need treatment. The "classical angiomyolipoma" is the only benign solid renal mass that can be characterized with confidence by imaging through the detection of a fat-containing lesion without calcifications. There is a large overlap of imaging features between benign and malignant renal masses that often makes difficult a correct characterization of these lesions. In this review, we discuss the imaging features of the main solid renal masses that may suggest a likely benign diagnosis.

Initial computed tomography imaging details during first-line systemic therapy is of significant prognostic value in patients with naïve, unresectable metastatic renal cell carcinoma

Purpose

We aimed to determine the prognostic significance of computed tomography imaging parameters of unresectable primary renal tumor lesions, obtained at baseline and at first follow-up, on overall survival in naïve, unresectable metastatic renal cell carcinoma patients during first-line systemic therapy.

Materials and methods

Clinicopathological parameters of 56 patients treated between 2007 and 2015, including imaging parameters (such as the longest tumor diameter, necrotic area diameter, and attenuation in primary renal tumor lesions on baseline vs. follow-up computed tomography), were retrospectively reviewed to derive predictive factors of overall survival. The best overall response was measured according to the RECIST v1.1.

Results

The median treatment period was 206.3 days and the median follow-up was 14.6 months. Forty-four (78.6%) patients progressed after a median 4.6 months of progression-free survival, and 6 (10.7%) patients survived with a median overall survival of 12.5 months. Multivariate analysis showed that the baseline tumor diameter (hazard ratio [HR] 0.903) and mean attenuation (HR 0.936), change of tumor diameter (HR 0.714) and necrosis diameter (HR 0.861), change in the percentage of tumor diameter (HR 1.483) and of necrosis diameter (HR 1.028) between baseline and follow-up computed tomography images; treatment duration (HR 0.986) and baseline serum hemoglobin (HR 1.790) and albumin level (HR 0.060) were significant factors for overall survival (p<0.05).

Conclusion

The study showed that baseline and first follow-up computed tomography findings of primary renal lesions during first-line systemic therapy are useful and significant predictors of OS in patients with naïve unresectable mRCC.

Abdominal seeding of renal cell carcinoma: radiologic, pathologic, and prognostic features

PURPOSE

We analyzed radiologic and histologic characteristics, and prognosis of abdominal seeding from renal cell carcinoma (RCC).

METHODS

Consecutive 25 patients with RCC and histologically or radiologically diagnosed abdominal seeding were analyzed. No patient had another type of malignancy. Histologic subtype, Fuhrman grade, sarcomatoid differentiation, and T-stage of primary tumors were assessed. Pre- or postoperative presentation of seeding was investigated. Median survival time and RCC-specific survival rates were evaluated.

RESULTS

Of 25 patients, 15 (60%) died and 4 (16%) were hopelessly discharged (median follow-up time, 6 months; range 1-62 months). Histologic subtypes were clear cell (76%, 19/25), papillary (16%, 4/25), chromophobe (4%, 1/25), and poorly differentiated (4%, 1/25). Fuhrman grades were 4 (48%, 12/25), 3 (36%, 9/25), 2 (12%, 3/25), and unknown (4%, 1/25). T-stage of the four patients with grade 2 or unknown was 3a. Sarcomatoid differentiation and postoperative occurrence were found in 32% (8/25) and 80% (20/25), respectively. Median survival time was 13 months, and 1-year, 2-year, and 3-year RCC-specific survival rates were 51%, 41%, and 31%, respectively.

CONCLUSION

Abdominal seeding may occur in various subtypes of RCC with high Fuhrman grade including sarcomatoid differentiation or high T-stage, and appears to be related to poor prognosis.

Gastrointestinal Involvement of Recurrent Renal Cell Carcinoma: CT Findings and Clinicopathologic Features

OBJECTIVE

To retrospectively evaluate the CT findings and clinicopathologic features in patients with gastrointestinal (GI) involvement of recurrent renal cell carcinoma (RCC).

MATERIALS AND METHODS

The medical records were reviewed for 15 patients with 19 pathologically proven GI tract metastases of RCC. The CT findings were analyzed to determine the involved sites and type of involvement; lesion size, morphology, and contrast enhancement pattern; and occurrence of lymphadenopathy, ascites and other complications.

RESULTS

The most common presentation was GI bleeding (66.7%). The average interval between nephrectomy and the detection of GI involvement was 30.4 ± 37.4 months. GI lesions were most commonly found in the ileum (36.8%) and duodenum (31.6%). A distant metastasis (80%) was more common than a direct invasion from metastatic lesions. The mean lesion size was 34.1 ± 15.0 mm. Intraluminal polypoid masses (63.2%) with hyperenhancement (78.9%) and heterogeneous enhancement (63.2%) were the most common findings. No patients had regional lymphadenopathy. Complications occurred in four patients, with one each of bowel obstruction, intussusception, bile duct dilatation, and pancreatic duct dilatation.

CONCLUSION

GI involvement of recurrent RCC could be included in the differential diagnosis of patients with heterogeneous, hyperenhanced intraluminal polypoid masses in the small bowel on CT scans along with a relative paucity of lymphadenopathy.

Dual-Energy Computed Tomography in Genitourinary Imaging

Reignited by innovations in scanner engineering and software design, dual-energy computed tomography (CT) has come back into the clinical radiology arena in the last decade. Possibilities for noninvasive in vivo characterization of genitourinary disease, especially for renal stones and renal masses, have become the pinnacle offerings of dual-energy CT for body imaging in clinical practice. This article renders a state-of-the-art review on clinical applications of dual-energy CT in genitourinary imaging.

Dual energy CT allows for improved characterization of response to antiangiogenic treatment in patients with metastatic renal cell cancer

OBJECTIVES

To evaluate the potential role of dual energy CT (DECT) to visualize antiangiogenic treatment effects in patients with metastatic renal cell cancer (mRCC) while treated with tyrosine-kinase inhibitors (TKI).

METHODS

26 patients with mRCC underwent baseline and follow-up single-phase abdominal contrast enhanced DECT scans. Scans were performed immediately before and 10 weeks after start of treatment with TKI. Virtual non-enhanced (VNE) and colour coded iodine images were generated. 44 metastases were measured at the two time points. Hounsfield unit (HU) values for VNE and iodine density (ID) as well as iodine content (IC) in mg/ml of tissue were derived. These values were compared to the venous phase DECT density (CTD) of the lesions. Values before and after treatment were compared using a paired Student's t test.

RESULTS

Between baseline and follow up, mean CTD and DECT-derived ID both showed a significant reduction (p < 0.005). The relative reduction measured in percent was significantly greater for ID than for CTD (49.8 ± 36,3 % vs. 29.5 ± 20.8 %, p < 0.005). IC was also significantly reduced under antiangiogenic treatment (p < 0.0001).

CONCLUSIONS

Dual energy CT-based quantification of iodine content of mRCC metastases allows for significantly more sensitive and reproducible detection of antiangiogenic treatment effects.

KEY POINTS

• A sign of tumour response to antiangiogenic treatment is reduced tumour perfusion. • DECT allows visualizing iodine uptake, which serves as a marker for vascularization. • More sensitive detection of antiangiogenic treatment effects in mRCC is possible.

Solitary parotid metastasis 8 years after a nephrectomy for renal cell carcinoma

Renal cell carcinoma is a common cancer, known for its aggressive behavior and ability to metastasize nearly every organ system in the body. While the cancer commonly spreads to a select few organs and metastasis usually develops within 5 years of diagnosis, there have been numerous case reports of atypical sites of metastasis and cases of relapse up to decades after treatment. We present a case a 65-year-old male who presented with right preauricular swelling 8 years after the initial diagnosis and right nephrectomy for clear cell renal cell cancer. We take a look at previous case reports with similar presentations.

Renal cell carcinoma: staging and surveillance

Renal cell carcinoma is a common malignancy with many histologic subtypes. Appropriate treatment depends not only upon the specific subtype but also the size of the tumor and extent of spread at time of presentation. Approximately 5% of RCCs are part of a hereditary syndrome which must also be considered in the therapeutic decisions. Although some RCCs are detected with ultrasound, CT or MR is required for staging. CT is used most commonly as it is most readily available and relatively less expensive than MR imaging. The TNM classification of the American Joint Committee on Cancer has largely replaced the Robson classification. Early detection, accurate staging, and improved treatment options have resulted in improved 5-year survival of patients with renal carcinoma.

Metastatic renal cell carcinoma imaging evaluation in the era of anti-angiogenic therapies

During the last decade, the arsenal of anti-angiogenic (AAG) agents used to treat metastatic renal cell carcinoma (RCC) has grown and revolutionized the treatment of metastatic RCC, leading to improved overall survival compared to conventional chemotherapy and traditional immunotherapy agents. AAG agents include inhibitors of vascular endothelial growth factor receptor signaling pathways and mammalian target of rapamycin inhibitors. Both of these classes of targeted agents are considered cytostatic rather than cytotoxic, inducing tumor stabilization rather than marked tumor shrinkage. As a result, decreases in tumor size alone are often minimal and/or occur late in the course of successful AAG therapy, while tumor devascularization is a distinct feature of AAG therapy. In successful AAG therapy, tumor devascularization manifests on computed tomography images as a composite of a decrease in tumor size, a decrease in tumor attenuation, and the development of tumor necrosis. In this article, we review Response Evaluation Criteria in Solid Tumors (RECIST)-the current standard of care for tumor treatment response assessment which is based merely on changes in tumor length-and its assessment of metastatic RCC tumor response in the era of AAG therapies. We then review the features of an ideal tumor imaging biomarker for predicting metastatic RCC response to a particular AAG agent and serving as a longitudinal tumor response assessment tool. Finally, a discussion of the more recently proposed imaging response criteria and new imaging trends in metastatic RCC response assessment will be reviewed.

Intracellular lipid in clear cell renal cell carcinoma tumor thrombus and metastases detected by chemical shift (in and opposed phase) MRI: radiologic-pathologic correlation

BACKGROUND

Clear cell renal cell carcinoma (RRC) characteristically contain intracellular lipid which is also detectable in tumor thrombus and metastases.

PURPOSE

To assess the incidence of intracellular lipid in clear cell RCC metastases and tumor thrombus using chemical shift MRI.

MATERIAL AND METHODS

With REB approval, 33 consecutive patients with clear cell RCC and tumor thrombus/metastatic disease underwent magnetic resonance imaging (MRI) over a 10-year period. Diagnosis was established by histopathology for tumor thrombi (n = 25) and metastases (n = 15) or growth for metastases (n = 14). Two blinded radiologists independently assessed for a signal intensity (SI) drop at chemical shift MRI (indicative of intracellular lipid) and a third radiologist established consensus. Chemical shift SI (CS-SI) index ([SItumorIP - SItumorOP]/SITumorIP x 100) was calculated. Inter-observer agreement was assessed using intra-class correlation (ICC) and tests of association were performed using the Chi-square test and Spearman correlation.

RESULTS

Using CS-MRI, intracellular lipid was detected in 36.4% of clear cell RCC, with moderate agreement, (ICC = 0.5). Intracellular lipid was detected in 20% of tumor thrombi and 20% of metastases with strong agreement (ICC = 0.73). Intracellular lipid within tumor thrombi/metastases was not associated with lipid within the primary tumor (P = 0.09). There was a correlation in CS-SI index between primary tumor and thrombi/metastases when lipid was detected in both lesions (r = 0.91, P = 0.005); however, there was no correlation when lipid was not detected in both lesions (r = -0.09, P = 0.72).

CONCLUSION

The presence of intracellular lipid in tumor thrombus and metastases from clear cell RCC is uncommon and, is not necessarily associated with lipid within the primary tumor at chemical shift MRI.