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Abdominal Radiology (New York) May 2021Differentiating renal tumours into grades and tumour subtype from medical imaging is important for patient management; however, there is an element of subjectivity when... (Review)
Review
PURPOSE
Differentiating renal tumours into grades and tumour subtype from medical imaging is important for patient management; however, there is an element of subjectivity when performed qualitatively. Quantitative analysis such as radiomics may provide a more objective approach. The purpose of this article is to systematically review the literature on computed tomography (CT) radiomics for grading and differentiating renal tumour subtypes. An educational perspective will also be provided.
METHODS
The Preferred Reporting Items for Systematic Reviews and Meta-Analyses checklist was followed. PubMed, Scopus and Web of Science were searched for relevant articles. The quality of each study was assessed using the Radiomic Quality Score (RQS).
RESULTS
13 studies were found. The main outcomes were prediction of pathological grade and differentiating between renal tumour types, measured as area under the curve (AUC) for either the receiver operator curve or precision recall curve. Features extracted to predict pathological grade or tumour subtype included shape, intensity, texture and wavelet (a type of higher order feature). Four studies differentiated between low-grade and high-grade clear cell renal cell cancer (RCC) with good performance (AUC = 0.82-0.978). One other study differentiated low- and high-grade chromophobe with AUC = 0.84. Finally, eight studies used radiomics to differentiate between tumour types such as clear cell RCC, fat-poor angiomyolipoma, papillary RCC, chromophobe RCC and renal oncocytoma with high levels of performance (AUC 0.82-0.96).
CONCLUSION
Renal tumours can be pathologically classified using CT-based radiomics with good performance. The main radiomic feature used for tumour differentiation was texture. Fuhrman was the most common pathologic grading system used in the reviewed studies. Renal tumour grading studies should be extended beyond clear cell RCC and chromophobe RCC. Further research with larger prospective studies, performed in the clinical setting, across multiple institutions would help with clinical translation to the radiologist's workstation.
Topics: Carcinoma, Renal Cell; Diagnosis, Differential; Humans; Kidney Neoplasms; Prospective Studies; Retrospective Studies; Tomography, X-Ray Computed
PubMed: 33136182
DOI: 10.1007/s00261-020-02832-9 -
Radiology Sep 2020Background Lipid-poor angiomyolipomas (AMLs) are challenging to differentiate from other renal lesions at imaging and often necessitate biopsy or surgery. If... (Meta-Analysis)
Meta-Analysis
Background Lipid-poor angiomyolipomas (AMLs) are challenging to differentiate from other renal lesions at imaging and often necessitate biopsy or surgery. If sufficiently accurate, MRI may play a role as a replacement test for biopsy. Purpose To perform a systematic review to evaluate the diagnostic performance of MRI for lipid-poor AMLs in patients with renal masses. Materials and Methods A systematic review of MEDLINE, EMBASE, Scopus, the Cochrane Library, and the "gray literature" (conference proceedings) was performed without language restriction through July 18, 2019, with the assistance of a health sciences librarian. Original articles with more than 10 patients evaluating the diagnostic performance of MRI, with histopathologic findings used as the reference standard, for the diagnosis of lipid-poor AMLs in patients with renal masses were included. Studies including AMLs with macroscopic fat and studies with insufficient data were excluded. Patient, clinical, MRI, and diagnostic performance parameters were independently acquired by two authors. Meta-analysis was performed by using a random-effects or bivariate mixed-effects regression model depending on the number of studies. Risk of bias of individual studies was evaluated by using Quality Assessment of Diagnostic Accuracy Studies-2. Results Twenty-three studies with 2196 patients and 25 contingency tables were included. The pooled sensitivity, specificity, and area under the receiver operating characteristic curve were 83% (95% confidence interval [CI]: 72%, 90%), 90% (95% CI: 84%, 94%), and 0.93 (95% CI: 0.91, 0.95), respectively. Considerable variability was present for several variables, including MRI parameters; however, subgroup analysis did not identify MRI sequence or field strength as sources for variability. All studies were at high risk of bias for index test domain because no reported thresholds were prespecified. Conclusion MRI shows promising accuracy for detecting lipid-poor angiomyolipomas (area under the receiver operating characteristic curve, >0.9), indicating a potential role as a replacement test for biopsy in selected patients. Studies evaluating MRI accuracy with a pragmatic algorithm and prespecified threshold may be helpful to confirm this potential role in the management pathway. © RSNA, 2020
Topics: Adolescent; Adult; Aged; Angiomyolipoma; Female; Humans; Kidney; Kidney Neoplasms; Magnetic Resonance Imaging; Male; Middle Aged; Sensitivity and Specificity; Young Adult
PubMed: 32602827
DOI: 10.1148/radiol.2020192070 -
European Radiology Jul 2020To perform a systematic review on apparent diffusion coefficient (ADC) values of renal tumor subtypes and meta-analysis on the diagnostic performance of ADC for... (Meta-Analysis)
Meta-Analysis
OBJECTIVES
To perform a systematic review on apparent diffusion coefficient (ADC) values of renal tumor subtypes and meta-analysis on the diagnostic performance of ADC for differentiation of localized clear cell renal cell carcinoma (ccRCC) from other renal tumor types.
METHODS
Medline, Embase, and the Cochrane Library databases were searched for studies published until May 1, 2019, that reported ADC values of renal tumors. Methodological quality was evaluated. For the meta-analysis on diagnostic test accuracy of ADC for differentiation of ccRCC from other renal lesions, we applied a bivariate random-effects model and compared two subgroups of ADC measurement with vs. without cystic and necrotic areas.
RESULTS
We included 48 studies (2588 lesions) in the systematic review and 13 studies (1126 lesions) in the meta-analysis. There was no significant difference in ADC of renal parenchyma using b values of 0-800 vs. 0-1000 (p = 0.08). ADC measured on selected portions (sADC) excluding cystic and necrotic areas differed significantly from whole-lesion ADC (wADC) (p = 0.002). Compared to ccRCC, minimal-fat angiomyolipoma, papillary RCC, and chromophobe RCC showed significantly lower sADC while oncocytoma exhibited higher sADC. Summary estimates of sensitivity and specificity to differentiate ccRCC from other tumors were 80% (95% CI, 0.76-0.88) and 78% (95% CI, 0.64-0.89), respectively, for sADC and 77% (95% CI, 0.59-0.90) and 77% (95% CI, 0.69-0.86) for wADC. sADC offered a higher area under the receiver operating characteristic curve than wADC (0.852 vs. 0.785, p = 0.02).
CONCLUSIONS
ADC values of kidney tumors that exclude cystic or necrotic areas more accurately differentiate ccRCC from other renal tumor types than whole-lesion ADC values.
KEY POINTS
• Selective ADC of renal tumors, excluding cystic and necrotic areas, provides better discriminatory ability than whole-lesion ADC to differentiate clear cell RCC from other renal lesions, with area under the receiver operating characteristic curve (AUC) of 0.852 vs. 0.785, respectively (p = 0.02). • Selective ADC of renal masses provides moderate sensitivity and specificity of 80% and 78%, respectively, for differentiation of clear cell renal cell carcinoma (RCC) from papillary RCC, chromophobe RCC, oncocytoma, and minimal-fat angiomyolipoma. • Selective ADC excluding cystic and necrotic areas are preferable to whole-lesion ADC as an additional tool to multiphasic MRI to differentiate clear cell RCC from other renal lesions whether the highest b value is 800 or 1000.
Topics: Adenoma, Oxyphilic; Angiomyolipoma; Carcinoma, Papillary; Carcinoma, Renal Cell; Diagnosis, Differential; Diffusion Magnetic Resonance Imaging; Humans; Kidney Neoplasms; ROC Curve; Sensitivity and Specificity
PubMed: 32144458
DOI: 10.1007/s00330-020-06740-w -
European Radiology Jun 2020(1) To assess the methodological quality of radiomics studies investigating histological subtypes, therapy response, and survival in patients with renal cell carcinoma... (Meta-Analysis)
Meta-Analysis
OBJECTIVES
(1) To assess the methodological quality of radiomics studies investigating histological subtypes, therapy response, and survival in patients with renal cell carcinoma (RCC) and (2) to determine the risk of bias in these radiomics studies.
METHODS
In this systematic review, literature published since 2000 on radiomics in RCC was included and assessed for methodological quality using the Radiomics Quality Score. The risk of bias was assessed using the Quality Assessment of Diagnostic Accuracy Studies tool and a meta-analysis of radiomics studies focusing on differentiating between angiomyolipoma without visible fat and RCC was performed.
RESULTS
Fifty-seven studies investigating the use of radiomics in renal cancer were identified, including 4590 patients in total. The average Radiomics Quality Score was 3.41 (9.4% of total) with good inter-rater agreement (ICC 0.96, 95% CI 0.93-0.98). Three studies validated results with an independent dataset, one used a publically available validation dataset. None of the studies shared the code, images, or regions of interest. The meta-analysis showed moderate heterogeneity among the included studies and an odds ratio of 6.24 (95% CI 4.27-9.12; p < 0.001) for the differentiation of angiomyolipoma without visible fat from RCC.
CONCLUSIONS
Radiomics algorithms show promise for answering clinical questions where subjective interpretation is challenging or not established. However, the generalizability of findings to prospective cohorts needs to be demonstrated in future trials for progression towards clinical translation. Improved sharing of methods including code and images could facilitate independent validation of radiomics signatures.
KEY POINTS
• Studies achieved an average Radiomics Quality Score of 10.8%. Common reasons for low Radiomics Quality Scores were unvalidated results, retrospective study design, absence of open science, and insufficient control for multiple comparisons. • A previous training phase allowed reaching almost perfect inter-rater agreement in the application of the Radiomics Quality Score. • Meta-analysis of radiomics studies distinguishing angiomyolipoma without visible fat from renal cell carcinoma show moderate diagnostic odds ratios of 6.24 and moderate methodological diversity.
Topics: Algorithms; Angiomyolipoma; Carcinoma, Renal Cell; Diagnosis, Differential; Humans; Informatics; Kidney Neoplasms; Magnetic Resonance Imaging; Tomography, X-Ray Computed
PubMed: 32060715
DOI: 10.1007/s00330-020-06666-3 -
Respiratory Research Feb 2020Lymphangioleiomyomatosis (LAM) is a rare, low-grade multisystem neoplastic disease. Most LAM patients are at a high risk of losing lung function at an accelerated rate... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Lymphangioleiomyomatosis (LAM) is a rare, low-grade multisystem neoplastic disease. Most LAM patients are at a high risk of losing lung function at an accelerated rate and developing progressive dyspnea. Recently, several studies have reported their experience with pharmacological treatments for LAM. Therefore, we conducted a systematic review and meta-analysis to assess the efficacy and safety of these therapies.
METHODS
PubMed (Medline), EMBASE, Cochrane Library, Web of Science and EBSCO Host were searched (until March 31, 2019) for eligible prospective studies regarding LAM patients treated with pharmacological treatments. Random effect models were used for quantitative analysis.
RESULTS
Fourteen prospective studies regarding five pharmacological treatments (including sirolimus, everolimus, doxycycline, triptorelin, and a combination therapy of sirolimus and hydroxychloroquine) were enrolled in our systematic review, and ten of them were used for the meta-analysis. Seven prospective studies reported that sirolimus was effective at improving or stabilizing lung function and alleviating renal angiomyolipoma (AML) in LAM patients. Subsequent quantitative analyses showed that during sirolimus treatment, the pooled values of lung function and 6-min walk distance (6MWD) were not significantly changed (P > 0.05), with the pooled response rate of AML being 0.62 (95% confidence intervals [CIs]: 0.43 to 0.82, I = 65%). Regarding everolimus, three prospective studies reported similar effects to those of sirolimus with regard to preserving lung function and reducing AMLs. The meta-analysis showed that the changes in lung function during everolimus treatment were not statistically significant (P > 0.05), while the pooled response rate of AML was 0.78 (95% CI: 0.68 to 0.88, I = 8%). Neither the qualitative nor the quantitative results confirmed the benefits of doxycycline or triptorelin treatment, and the effects of the combination therapy were unclear in LAM patients. Most of the adverse events during pharmacological treatments were low or moderate grade and tolerable.
CONCLUSIONS
Overall, sirolimus and everolimus were recommended for the treatment of LAM because they could stabilize lung function and alleviate renal AML. Doxycycline and triptorelin were not recommended for the treatment of LAM because no beneficial outcomes were consistently observed. The efficacy and safety of combination therapy remain to be further explored.
Topics: Antibiotics, Antineoplastic; Antineoplastic Agents; Clinical Trials as Topic; Drug Therapy, Combination; Enzyme Inhibitors; Everolimus; Humans; Hydroxychloroquine; Hyperlipidemias; Lymphangioleiomyomatosis; Prospective Studies; Sirolimus; Stomatitis; Treatment Outcome
PubMed: 32059669
DOI: 10.1186/s12931-020-1316-3 -
European Urology Oncology Feb 2020Little is known about the natural history of sporadic angiomyolipomas (AMLs); there is uncertainty regarding the indications of treatment and treatment options.
Management of Sporadic Renal Angiomyolipomas: A Systematic Review of Available Evidence to Guide Recommendations from the European Association of Urology Renal Cell Carcinoma Guidelines Panel.
CONTEXT
Little is known about the natural history of sporadic angiomyolipomas (AMLs); there is uncertainty regarding the indications of treatment and treatment options.
OBJECTIVE
To evaluate the indications, effectiveness, harms, and follow-up of different management modalities for sporadic AML to provide guidance for clinical practice.
EVIDENCE ACQUISITION
A systematic review of the literature was undertaken, incorporating Medline, Embase, and the Cochrane Library (from 1 January 1990 to 30 June 2017), in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. No restriction on study design was imposed. Patients with sporadic AML were included. The main interventions included active surveillance, surgery (nephron-sparing surgery and radical nephrectomy), selective arterial embolisation, and percutaneous or laparoscopic thermal ablations (radiofrequency, microwaves, or cryoablation). The outcomes included indications for active treatment, AML growth rate, AML recurrence rate, risk of bleeding, post-treatment renal function, adverse events of treatments, and modalities of follow-up. Risk of bias assessment was performed using standard Cochrane methods.
EVIDENCE SYNTHESIS
Among 2704 articles identified, 43 were eligible for inclusion (zero randomised controlled trials, nine nonrandomised comparative retrospective studies, and 34 single-arm case series). Most studies were retrospective and uncontrolled, and had a moderate to high risk of bias.
CONCLUSIONS
In active surveillance series, spontaneous bleeding was reported in 2% of patients and active treatment was undertaken in 5%. Active surveillance is the most chosen option in 48% of the cases, followed by surgery in 31% and selective arterial embolisation in 17% of the cases. Selective arterial embolisation appeared to reduce AML volume but required secondary treatment in 30% of the cases. Surgery (particularly nephron-sparing surgery) was the most effective treatment in terms of recurrence and need for secondary procedures. Thermal ablation was an infrequent option. The association between AML size and the risk of bleeding remained unclear; as such the traditional 4-cm cut-off should not per se trigger active treatment. In spite of the limitations and uncertainties relating to the evidence base, the findings may be used to guide and inform clinical practice, until more robust data emerge.
PATIENT SUMMARY
Sporadic angiomyolipoma (AML) is a benign tumour of the kidney consisting of a mixture of blood vessels, fat, and muscle. Large tumours may have a risk of spontaneous bleeding. However, the size beyond which these tumours need to be treated remains unclear. Most small AMLs can be monitored without any active treatment. For those who need treatment, options include surgical removal of the tumour or stopping its blood supply (selective embolisation). Surgery has a lower recurrence rate and lower need for a repeat surgical procedure.
Topics: Angiomyolipoma; Carcinoma, Renal Cell; Europe; Female; Humans; Kidney; Kidney Neoplasms; Male; Retrospective Studies
PubMed: 31171501
DOI: 10.1016/j.euo.2019.04.005 -
Orphanet Journal of Rare Diseases Aug 2018Lymphangioleiomyomatosis (LAM) is a rare lung disease and the mammalian target of the rapamycin (mTOR) inhibitors has been used as an effective therapy. Here we... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Lymphangioleiomyomatosis (LAM) is a rare lung disease and the mammalian target of the rapamycin (mTOR) inhibitors has been used as an effective therapy. Here we conducted a systematic review and meta-analysis with the aims to quantify the efficacy and safety of mTOR inhibitors in LAM patients.
METHODS
The following databases were searched for clinical trials regarding LAM patients treated with mTOR inhibitors until December 2017: Pubmed, Embase, Cochrane Library and OVID medicine. Random effect models were used for the quantitative analysis.
RESULTS
Nine eligible studies were included in our systematic review, 7 of which were used for the meta-analysis. In LAM patients, mTOR inhibitors improved forced expiratory volume in 1 s (FEV) and forced vital capacity (FVC) significantly, with the weighted mean difference (WMD) 0.15 L (95%CI: 0.08 to 0.22, P < 0.01, I = 0%) and 0.22 L (95%: 0.11 to 0.32, P < 0.01, I = 0%) respectively. There was no significant change in neither the diffusing capacity for carbon monoxide (WMD: 0.51 ml/mm Hg/min, 95%CI: -0.48 to 1.49, P = 0.31, I = 0%) nor 6-min walking distance (WMD: 5.29 m, 95%CI: -18.01 to 28.59, P = 0.66, I = 1%). The weighted partial response rate was 0.68 (95%CI: 0.53 to 0.84, P < 0.01, I = 72%) for renal angiomylipoma. The cumulative incidence rates of common safety events were 50, 40, 23, 20 and 19% for oral mucositis, hyperlipidemia, headache, bone marrow suppression, and diarrhea, respectively. And most events were low grade and tolerant.
CONCLUSIONS
In LAM patients, there are improvements of FEV and FVC after the application of mTOR inhibitors and over a half achieved the shrinkage of renal angiomyolipoma.
TRIAL REGISTRATION
PROSPERO registration number: CRD42018085470. Registered 22 January 2018.
Topics: Animals; Antineoplastic Agents; Humans; Lymphangioleiomyomatosis; TOR Serine-Threonine Kinases
PubMed: 30107845
DOI: 10.1186/s13023-018-0874-7 -
International Urology and Nephrology Nov 2017To conduct a systematic literature review on spontaneous renal hemorrhage (SRH) in a contemporary cohort describing patterns in etiology and treatment. (Review)
Review
OBJECTIVE
To conduct a systematic literature review on spontaneous renal hemorrhage (SRH) in a contemporary cohort describing patterns in etiology and treatment.
METHODS
A systematic search of MEDLINE and CENTRAL databases was conducted to include articles, including case reports and case series on SRH published from 2000 to 2016. Full-text manuscripts were reviewed for clinical parameters which were collated and analyzed with univariate methods.
RESULTS
Seventy-nine publications met inclusion criteria, reporting on 102 cases. Renal neoplasms (56.9%) and polyarteritis nodosa (PAN) (11.8%) remained as the most common overall and vascular causes of SRH, respectively. Angiomyolipoma (AML) was the most common causative renal neoplasm (74.1%), and patients were more likely to be female and present with macroscopic hematuria than those with vasculitis, while malignant neoplasms were more common in men. Proportions of SRH due to malignant neoplasms (specifically renal cell carcinoma, RCC) were reported less than PAN. Among this contemporary series, transarterial embolization (TAE) was most commonly used for acute SRH (42.2%).
CONCLUSIONS
Renal neoplasms remain as the most common cause of SRH, of which AML predominates, while PAN is currently the second most common etiology in acute SRH, replacing RCC. Minimally invasive approaches, such as TAE and conservative/medical management, were preferred to initial surgery.
SYSTEMATIC REVIEW REGISTRATION
PROSPERO registration number CRD42017069222.
Topics: Angiomyolipoma; Carcinoma, Renal Cell; Embolization, Therapeutic; Hematuria; Hemorrhage; Humans; Kidney Neoplasms; Polyarteritis Nodosa; Sex Factors
PubMed: 28871505
DOI: 10.1007/s11255-017-1694-8 -
AJR. American Journal of Roentgenology Nov 2017The purpose of this article is to systematically review and perform a meta-analysis of the diagnostic performance of CT for diagnosis of fat-poor angiomyolipoma (AML) in... (Meta-Analysis)
Meta-Analysis Review
OBJECTIVE
The purpose of this article is to systematically review and perform a meta-analysis of the diagnostic performance of CT for diagnosis of fat-poor angiomyolipoma (AML) in patients with renal masses.
MATERIALS AND METHODS
MEDLINE and EMBASE were systematically searched up to February 2, 2017. We included diagnostic accuracy studies that used CT for diagnosis of fat-poor AML in patients with renal masses, using pathologic examination as the reference standard. Two independent reviewers assessed the methodologic quality using the Quality Assessment of Diagnostic Accuracy Studies-2 tool. Sensitivity and specificity of included studies were calculated and were pooled and plotted in a hierarchic summary ROC plot. Sensitivity analyses using several clinically relevant covariates were performed to explore heterogeneity.
RESULTS
Fifteen studies (2258 patients) were included. Pooled sensitivity and specificity were 0.67 (95% CI, 0.48-0.81) and 0.97 (95% CI, 0.89-0.99), respectively. Substantial and considerable heterogeneity was present with regard to sensitivity and specificity (I = 91.21% and 78.53%, respectively). At sensitivity analyses, the specificity estimates were comparable and consistently high across all subgroups (0.93-1.00), but sensitivity estimates showed significant variation (0.14-0.82). Studies using pixel distribution analysis (n = 3) showed substantially lower sensitivity estimates (0.14; 95% CI, 0.04-0.40) compared with the remaining 12 studies (0.81; 95% CI, 0.76-0.85).
CONCLUSION
CT shows moderate sensitivity and excellent specificity for diagnosis of fat-poor AML in patients with renal masses. When methods other than pixel distribution analysis are used, better sensitivity can be achieved.
Topics: Angiomyolipoma; Humans; Kidney Neoplasms; Sensitivity and Specificity; Tomography, X-Ray Computed
PubMed: 28834444
DOI: 10.2214/AJR.17.18184 -
Liver International : Official Journal... Sep 2017Hepatic Angiomyolipoma (HAML) is a rare mesenchymal liver tumour assumed to be predominantly benign, although incidental cases with malignant behaviour such as invasive... (Review)
Review
Hepatic Angiomyolipoma (HAML) is a rare mesenchymal liver tumour assumed to be predominantly benign, although incidental cases with malignant behaviour such as invasive growth, recurrence after resection and metastases have been reported. The aim of this systematic review was to assess the biological behaviour, estimate the risk of HAML related mortality and recommend on a justifiable management strategy. We performed a systematic literature search in Embase, Medline, Web-of-Science, Scopus, Pubmed Publisher, Cochrane and Google Scholar. We included all articles published from inception until March 2016 which reported on follow-up of various treatment strategies. We included 18 articles reporting on 292 patients. Male:female ratio was estimated at 1:3 with gender not reported in 31 cases. Of 292 patients 247 were treated with surgery, including one liver transplant, seven with chemotherapy or Sirolimus, three with embolization, and 35 conservatively. Recurrence after resection was described in 6/247 (2.4%) with pathologically proven HAML resulting in metastases and death in 2/247 (mortality rate 0.8%). Progression was described in 6/35 patients treated conservatively (21.4%). Two of 12 patients with malignant behaviour of HAML had an epithelioid-type HAML, of the remaining 10 histological subtype was undefined. With a risk estimate of 0.8% in surgically treated patients HAML related mortality is very low. Biopsy is indicated when imaging is inconclusive. In case of certain HAML diagnosis on imaging conservative management with annual imaging is justified. Resection should be considered in case of symptoms, inconclusive biopsy or growth in follow-up.
Topics: Angiomyolipoma; Antibiotics, Antineoplastic; Hepatectomy; Humans; Liver; Liver Neoplasms; Liver Transplantation; Neoplasm Recurrence, Local; Sirolimus
PubMed: 28177188
DOI: 10.1111/liv.13381