Diffusion-weighted MRI in bladder carcinoma: the differentiation between tumor recurrence and benign changes after resection

The role of multiparametric MRI-based VI-RADS in predicting the need for a second TURB

PURPOSE

To prospectively evaluate the value of Vesical Imaging Reporting and Data System (VI‑RADS) prior to initial transurethral resection of the bladder (TURB) in predicting residual tumor at second TURB and subsequent prognosis of patients.

METHODS

We enrolled suspected bladder cancer patients and scheduled multiparametric magnetic resonance imaging (mpMRI) of bladder for them before initial TURB. Second TURB were conducted based on initial resection reports, with comparisons made between patients with VI-RADS scores <3 and ≥3 regarding residual tumor rate, recurrence-free survival (RFS) and progression-free survival (PFS). Predictive efficacy of VI-RADS was assessed using Chi-square tests, logistic and Cox regression analyses, ROC curves, and Kaplan-Meier analyses.

RESULTS

A total of 108 patients were included, and residual tumors were detected in 25.0% (27/108) of them at second TURB, with a significant difference between patients with VI-RADS score <3 and ≥3 (8/81 vs. 19/27, p <0.001). VI-RADS ≥3 demonstrated a sensitivity of 70.4%, specificity of 90.1%, positive predictive value (PPV) of 70.4%, and negative predictive value (NPV) of 90.1%. Stratified analysis showed VI-RADS achieved a NPV of 95.2% for disease-free Ta patients, while 84.6% for T1 patients. After a median follow-up of 30 months for the 92 patients, 24 experienced tumor recurrence. VI-RADS ≥3 was found to be an independent predictor of tumor recurrence (HR = 4.297, p = 0.003).

CONCLUSIONS

VI-RADS ≥3 is associated with higher residual tumor rate at second TURB and higher recurrence risk. It might be an option for omitting second TURB when VI-RADS is <3, especially for Ta patients.

Comparative diagnostic performance of VI-RADS based on biparametric and multiparametric MRI in predicting muscle invasion in bladder cancer

BACKGROUND

Vesical Imaging-Reporting and Data System (VI-RADS) based on multiparametric magnetic resonance imaging (mp-MRI) performed well in diagnosing muscle-invasive bladder cancer (MIBC). However, certain cases may present challenges in determining the final VI-RADS score using only T2-weighted imaging (T2WI) and diffusion-weighted imaging (DWI) sequences, especially in the absence of dynamic contrast-enhanced (DCE) imaging. This study aims to evaluates whether biparametric MRI (bp-MRI) achieve comparable diagnostic performance to mp-MRI for predicting MIBC and seeks to identify the most suitable bp-MRI criterion by establishing four specific conditions based on T2WI and DWI.

METHODS

A retrospective analysis was conducted on 447 patients who underwent preoperative mp-MRI. Images were evaluated according to the VI-RADS protocol by three independent readers. In the bp-DWI and bp-DWI Plus criteria, DWI was the primary sequence used for lesion assessment, while T2WI was the primary sequence for bp-T2WI and bp-T2WI Plus criteria. The Plus criteria (bp-DWI Plus and bp-T2WI Plus) assigned a final VI-RADS score of 4 when both T2WI and DWI scores were 3. The gold standard for diagnosis was histopathological evaluation after surgery. Diagnostic performance was evaluated by comparing the area under the curve (AUC), sensitivity, specificity, and inter-reader agreement using Cohen's kappa analysis.

RESULTS

Among 447 patients, 304 confirmed as NMIBC and 143 as MIBC. The kappa values were 0.876, 0.873, 0.873, 0.642, and 0.642 for mp-MRI, bp-DWI, bp-DWI Plus, bp-T2WI, and bp-T2WI Plus, respectively, when VI-RADS cutoff > 2. Similarly, when cutoff > 3, the kappa values were 0.848, 0.811, 0.873, 0.811, and 0.873. No significant differences were observed between mp-MRI and bp-DWI (AUC: 0.916 vs. 0.912, p = 0.498), but mp-MRI and bp-DWI had higher AUCs compared to bp-DWI Plus, bp-T2WI, and bp-T2WI Plus.

CONCLUSIONS

Both mp-MRI and bp-DWI demonstrate excellent performance in predicting MIBC, with bp-DWI being an alternative to mp-MRI.

TRIAL REGISTRATION

retrospectively.

VI steps to achieve VI-RADS assessment

Bladder cancer is categorized into nonmuscle-invasive bladder cancer (NMIBC) and muscle-invasive bladder cancer (MIBC), distinguished by the presence of detrusor muscle invasion. Urothelial cell carcinoma is the most common subtype of bladder cancer. Transurethral resection of bladder tumor (TURBT) is the standard approach for staging and managing NMIBC, while radical cystectomy remains the cornerstone treatment for MIBC. Multiparametric magnetic resonance imaging (mpMRI), comprising morphological imaging sequences (high-resolution T2-weighted images) and functional imaging sequences (dynamic contrast-enhanced images and diffusion-weighted images), serves as an ideal modality. It provides high-contrast resolution for visualizing bladder wall layers, thereby enabling proper and timely staging of bladder cancer. MRI can guide sampling resection and identify patients understaged after primary TURBT, facilitating appropriate surgical restaging. In 2018, the Vesical Imaging Reporting and Data System (VI-RADS), implementing a 5-point scale, was developed to standardize MRI protocols and reporting criteria-including tumor location, size, morphology, and invasiveness. The aim of this article is to navigate through all the steps to achieve VI-RADS assessment and to discuss practical pearls and pitfalls in the use of mpMRI. This approach can aid in pre-TURBT prediction of muscle invasion, representing an important asset in bladder cancer staging.

Utility of MRI in NMIBC and feasibility of avoiding Re-TURB in carefully selected patients: a systematic review

OBJECTIVE

This systematic review was conducted to synthesize current research on the role of repeated transurethral resection of the bladder (re-TURB) and the emerging use of magnetic resonance imaging (MRI) in discerning patient suitability for safely foregoing this procedure.

EVIDENCE ACQUISITION

Employing a methodical literature search, we consulted several bibliographic databases including PubMed, Science Direct, Scopus, and Embase. The review process adhered strictly to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA 2020) guidelines.

EVIDENCE SYNTHESIS

We evaluated data from 667 patients (mean age 65.8 years; age range 59-75 years) who underwent MRI prior to potential re-TURB. The gap between initial TURB and MRI was reported as 42 days in one study, while the interval between MRI and subsequent cystoscopy, with or without biopsy, varied from 21 days to 3 months. Initial TURB pathology for non-muscle invasive bladder cancer (NMIBC) patients identified stage Ta in 177 (42.5%) and T1 in 246 (57.5%) patients across three studies. High-grade and low-grade pathologic classifications were reported in 377 (64.5%) and 207 (35.5%) patients respectively in two studies. The VI-RADS scoring system's sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) for the detection of bladder cancer recurrence were 89%, 85.5%, 82.7%, and 96%, respectively. A total of 365 patients (54.7%) underwent re-TUR. Among NMIBC patients, re-TUR pathology revealed Ta in 22 cases (5.4%) and pT1 in 179 cases (44%) with VI-RADS 1-2, while no cases of Ta (0%) and 37 cases of T1 (9%) were reported with VI-RADS 4-5, as documented in two studies. Notably, only 69 patients (10.7%) were identified as having MIBC across all studies.

CONCLUSION

MRI is demonstrating reliability as a diagnostic tool for non-muscle invasive bladder cancers. The VI-RADS scoring system appears to be a promising approach in selecting patients for re-TURB. DW-MRI may serve as a primary diagnostic examination for patient follow-up post-TURB.

Current Status of Magnetic Resonance Imaging Use in Bladder Cancer

ABSTRACT

Bladder cancer (BC) is a significant global health concern, with over 500,000 new cases and 200,000 deaths annually, emphasizing the need for accurate staging and effective management. Traditional diagnostic techniques, such as cystoscopy and transurethral resection, are fundamental but have limitations in accurately assessing the depth of invasion. These limitations include the possibility of understaging and procedural variability, which can significantly impact treatment decisions. This review focuses on the role of multiparametric magnetic resonance imaging (mpMRI) in the diagnosis and staging of BC, particularly emphasizing the Vesical Imaging-Reporting and Data System (VI-RADS) framework. By enhancing interpretive consistency and diagnostic accuracy, mpMRI and VI-RADS offer detailed visualization of tumor characteristics and depth of invasion, while reducing the need for more invasive traditional methods. These advancements not only improve staging accuracy but also enhance treatment planning, underscoring the importance of advanced imaging in evolving BC management and positively influencing patient outcomes.

Retrospective analysis of multiparametric MRI in predicting complete pathologic response of neo-adjuvant chemotherapy in bladder cancer

BACKGROUND

Muscle invasive bladder cancer (MIBC) treatment combines systemic therapy and radical cystectomy (RC) or local (chemo-)radiotherapy. Response to systemic therapy is an important outcome predictor but is difficult to assess pre-operatively.

METHODS

We analyzed multiparametric MRI (mpMRI) in consecutive MIBC patients receiving cisplatin-based neo-adjuvant chemotherapy at our institution. Two readers, blinded for pathological outcome, independently scored mpMRI before and after 2 and 4 cycles using both a qualitative 3-step method and nacVI-RADS. We analyzed accuracy of mpMRI scores to predict pathologic complete response (pCR) and inter-observer agreement.

RESULTS

We analyzed 46 patients receiving NAC, 6 patients did not undergo RC after NAC and were excluded. Eleven out of 40 (28%) patients showed a pCR. mpMRI could be assessed in over 90% of patients. Radiologic complete response (rCR) using both methods was significantly associated with pCR, with an overall specificity of 96% and sensitivity of 36% and a high inter-observer agreement. rCR as assessed by the 3-step score was significantly associated with disease free survival (DFS) benefit.

CONCLUSION

The use of nacVI-RADS can predict pCR after NAC with high specificity but low sensitivity and a high inter-observer agreement. A 3-step score adds value in determining local residual disease, rCR assessed by this method could correlate with DFS benefit. mpMRI scores should be prospectively assessed in future trials of multimodal management of MIBC and can be a predictive asset in routine clinical management.

The Value of Amide Proton Transfer MRI in the Diagnosis of Malignant and Benign Urinary Bladder Lesions: Comparison With Diffusion-Weighted Imaging

BACKGROUND

Conventional magnetic resonance imaging (MRI) has certain limitations in distinguishing between malignant and benign urinary bladder (UB) lesions. Amide proton transfer (APT) imaging may provide more diagnostic information than diffusion-weighted imaging (DWI) to distinguish between malignant and benign UB.

PURPOSE

To investigate the potential of APT imaging in the diagnosis of malignant and benign UB lesions and to compare its diagnostic efficacy with that of conventional DWI.

STUDY TYPE

Prospective.

SUBJECTS

Eighty patients with UB lesions.

FIELD STRENGTH/SEQUENCE

A 3.0 T/turbo spin echo (TSE) T1-weighted and T2-weighted imaging, single-shot echo planar DWI, and three-dimensional TSE APT imaging.

ASSESSMENT

Patients underwent radical cystectomy or transurethral resection of the bladder lesions within 2 weeks after CT urography and MRI examination. APT signal intensity in UB lesions was quantified by the asymmetric magnetization transfer ratio (MTRasym). MTRasym and apparent diffusion coefficient (ADC) values were measured and compared between malignant and benign UB lesions.

STATISTICAL TESTS

Kolmogorov-Smirnov test, Student's t test or Mann-Whitney U test, Spearman rank correlation coefficient, area under the receiver operating characteristic (ROC) curve (AUC), Delong test, and intraclass correlation coefficient (ICC). The significance threshold was set at P < 0.05.

RESULTS

Thirty-two patients had pathologically confirmed benign UB lesions, including 2 bladder leiomyomas, 1 submucosal amyloidosis, 1 inflammatory myofibroblastic tumor, and 28 inflammatory lesions, and 48 patients had pathologically confirmed urothelial carcinoma. Urothelial carcinomas showed significantly higher MTRasym values (1.53% [0.74%] vs. 0.85% [0.23%]) and significantly lower ADC values (1.24 ± 0.34 × 10-3 mm2/s vs. 1.43 ± 0.22 × 10-3 mm2/s) than benign UB lesions. The MTRasym value (AUC = 0.928) was significantly better in differentiating urothelial carcinoma from benign UB lesions than the ADC value (AUC = 0.722).

DATA CONCLUSION

APT imaging may have value in discriminating malignant from benign UB lesions and has better diagnostic performance than DWI.

LEVEL OF EVIDENCE

3 TECHNICAL EFFICACY: Stage 2.

The role of VI-RADS scoring criteria for predicting oncological outcomes in bladder cancer

PURPOSE

Our purpose was to evaluate the prognostic value of Vesical Imaging Reporting and Data System (VI-RADS) in bladder cancer (BCa) staging and predicting recurrence or progression.

METHODS

We retrospectively analyzed the prospectively collected data from 96 patients with bladder tumors who underwent VI-RADS-based multiparametric magnetic resonance imaging (mpMRI) before endourological treatment from April 2021 to December 2022. Diagnostic performance was evaluated by comparing mpMRI reports with final pathology, using logistic regression for muscle-invasive bladder cancer (MIBC) predictors. Follow-up until May 2023 included Kaplan-Meier and Cox regression analysis to assess VI-RADS predictive roles for recurrence-free survival (RFS) and progression-free survival (PFS).

RESULTS

A total of 96 patients (19.8% women, 80.2% men; median age 68.0 years) were included, with 71% having primary tumors and 29% recurrent BCa. Multiparametric MRI exhibited high sensitivity (92%) and specificity (79%) in predicting MIBC, showing no significant differences between primary and recurrent cancers (AUC: 0.96 vs. 0.92, P = .565). VI-RADS emerged as a key predictor for MIBC in both univariate (OR: 40.3, P < .001) and multivariate (OR: 54.6, P < .001) analyses. Primary tumors with VI-RADS ≥ 3 demonstrated significantly shorter RFS (P = .02) and PFS (P = .04).

CONCLUSIONS

In conclusion, mpMRI with VI-RADS has a high diagnostic value in predicting MIBC in both primary and recurrent BCa. A VI-RADS threshold ≥ 3 is a strong predictor for MIBC, and in primary tumors predicts early recurrence and progression.

Multiparametric MR characterization for human epithelial growth factor receptor 2 expression in bladder cancer: an exploratory study

PURPOSE

To investigate the application value of multiparametric MRI in evaluating the expression status of human epithelial growth factor receptor 2 (HER2) in bladder cancer (BCa).

METHODS

From April 2021 to July 2023, preoperative imaging manifestations of 90 patients with pathologically confirmed BCa were retrospectively collected and analyzed. All patients underwent multiparametric MRI including synthetic MRI, DWI, from which the T1, T2, proton density (PD) and apparent diffusion coefficient (ADC) values were obtained. The clinical and imaging characteristics as well as quantitative parameters (T1, T2, PD and ADC values) between HER2-positive and -negative BCa were compared using student t test and chi-square test. The diagnostic efficacy of parameters in predicting HER2 expression status was evaluated by calculating the area under ROC curve (AUC).

RESULTS

In total, 76 patients (mean age, 63.59 years ± 12.84 [SD]; 55 men) were included: 51 with HER2-negative and 25 with HER2-positive BCa. HER2-positive group demonstrated significantly higher ADC, T1, and T2 values than HER2-negative group (all P < 0.05). The combination of ADC values and tumor grade yielded the best diagnostic performance in evaluating HER2 expression level with an AUC of 0.864.

CONCLUSION

The multiparametric MR characterization can accurately evaluate the HER2 expression status in BCa, which may further guide the determination of individualized anti-HER2 targeted therapy strategies.

Evaluation of magnetic resonance imaging for bladder cancer detection following transurethral resection of bladder tumour (TURBT)

PURPOSE

To evaluate the performance of MRI for detection of bladder cancer following transurethral resection of bladder tumour (TURBT).

METHODS

This single-centre retrospective study included forty-one consecutive patients with bladder cancer who underwent bladder MRI after TURBT. Two uroradiologists retrospectively assessed the presence of tumour using bladder MRI with and without DWI (diffusion weighted imaging) using a five-point Likert scale. Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were calculated and inter-reader agreement was assessed. Histopathology was used as the reference standard.

RESULTS

24 out of 41 patients (58.5%) had no residual tumour or Tis (carcinoma in situ) after TURBT. Sensitivity, specificity, PPV and NPV for detection of tumour using T1WI (T1-weighted imaging) and T2WI (T2-weighted imaging) was 50.0%, 54.6%, 21.1%, and 81.8%, respectively and for T1WI, T2WI and DWI combined was 100%, 76.5%, 50.0% and 100%, respectively. Overestimation of tumour was more common than underestimation. MRI showed high accuracy for patients in whom there was no residual tumour (78.9%). Inter-reader agreement for tumour detection improved from fair (κ = 0.54) to moderate (κ = 0.70) when DWI was included.

CONCLUSION

Non-contrast MRI with DWI showed high sensitivity and relatively high specificity for detection of residual tumour after TURBT. Inter-reader agreement improved from fair to moderate with the addition of DWI. MRI can be useful after TURBT in order to guide further management.

Imaging at the nexus: how state of the art imaging techniques can enhance our understanding of cancer and fibrosis

Both cancer and fibrosis are diseases involving dysregulation of cell signaling pathways resulting in an altered cellular microenvironment which ultimately leads to progression of the condition. The two disease entities share common molecular pathophysiology and recent research has illuminated the how each promotes the other. Multiple imaging techniques have been developed to aid in the early and accurate diagnosis of each disease, and given the commonalities between the pathophysiology of the conditions, advances in imaging one disease have opened new avenues to study the other. Here, we detail the most up-to-date advances in imaging techniques for each disease and how they have crossed over to improve detection and monitoring of the other. We explore techniques in positron emission tomography (PET), magnetic resonance imaging (MRI), second generation harmonic Imaging (SGHI), ultrasound (US), radiomics, and artificial intelligence (AI). A new diagnostic imaging tool in PET/computed tomography (CT) is the use of radiolabeled fibroblast activation protein inhibitor (FAPI). SGHI uses high-frequency sound waves to penetrate deeper into the tissue, providing a more detailed view of the tumor microenvironment. Artificial intelligence with the aid of advanced deep learning (DL) algorithms has been highly effective in training computer systems to diagnose and classify neoplastic lesions in multiple organs. Ultimately, advancing imaging techniques in cancer and fibrosis can lead to significantly more timely and accurate diagnoses of both diseases resulting in better patient outcomes.

Enhancing recurrence risk prediction for bladder cancer using multi-sequence MRI radiomics

OBJECTIVE

We aimed to develop a radiomics-clinical nomogram using multi-sequence MRI to predict recurrence-free survival (RFS) in bladder cancer (BCa) patients and assess its superiority over clinical models.

METHODS

A retrospective cohort of 229 BCa patients with preoperative multi-sequence MRI was divided into a training set (n = 160) and a validation set (n = 69). Radiomics features were extracted from T2-weighted images, diffusion-weighted imaging, apparent diffusion coefficient, and dynamic contrast-enhanced images. Effective features were identified using the least absolute shrinkage and selection operator (LASSO) method. Clinical risk factors were determined via univariate and multivariate Cox analysis, leading to the creation of a radiomics-clinical nomogram. Kaplan-Meier analysis and log-rank tests assessed the relationship between radiomics features and RFS. We calculated the net reclassification improvement (NRI) to evaluate the added value of the radiomics signature and used decision curve analysis (DCA) to assess the nomogram's clinical validity.

RESULTS

Radiomics features significantly correlated with RFS (log-rank p < 0.001) and were independent of clinical factors (p < 0.001). The combined model, incorporating radiomics features and clinical data, demonstrated the best prognostic value, with C-index values of 0.853 in the training set and 0.832 in the validation set. Compared to the clinical model, the radiomics-clinical nomogram exhibited superior calibration and classification (NRI: 0.6768, 95% CI: 0.5549-0.7987, p < 0.001).

CONCLUSION

The radiomics-clinical nomogram, based on multi-sequence MRI, effectively assesses the BCa recurrence risk. It outperforms both the radiomics model and the clinical model in predicting BCa recurrence risk.

CRITICAL RELEVANCE STATEMENT

The radiomics-clinical nomogram, utilizing multi-sequence MRI, holds promise for predicting bladder cancer recurrence, enhancing individualized clinical treatment, and performing tumor surveillance.

KEY POINTS

• Radiomics plays a vital role in predicting bladder cancer recurrence. • Precise prediction of tumor recurrence risk is crucial for clinical management. • MRI-based radiomics models excel in predicting bladder cancer recurrence.

Progress of Multiparameter Magnetic Resonance Imaging in Bladder Cancer: A Comprehensive Literature Review

Magnetic resonance imaging (MRI) has been proven to be an indispensable imaging method in bladder cancer, and it can accurately identify muscular invasion of bladder cancer. Multiparameter MRI is a promising tool widely used for preoperative staging evaluation of bladder cancer. Vesical Imaging-Reporting and Data System (VI-RADS) scoring has proven to be a reliable tool for local staging of bladder cancer with high accuracy in preoperative staging, but VI-RADS still faces challenges and needs further improvement. Artificial intelligence (AI) holds great promise in improving the accuracy of diagnosis and predicting the prognosis of bladder cancer. Automated machine learning techniques based on radiomics features derived from MRI have been utilized in bladder cancer diagnosis and have demonstrated promising potential for practical implementation. Future work should focus on conducting more prospective, multicenter studies to validate the additional value of quantitative studies and optimize prediction models by combining other biomarkers, such as urine and serum biomarkers. This review assesses the value of multiparameter MRI in the accurate evaluation of muscular invasion of bladder cancer, as well as the current status and progress of its application in the evaluation of efficacy and prognosis.

Evaluating residual tumor after neoadjuvant chemotherapy for muscle-invasive urothelial bladder cancer: diagnostic performance and outcomes using biparametric vs. multiparametric MRI

BACKGROUND

Neoadjuvant chemotherapy (NAC) before radical cystectomy is standard of care in patients with muscle-invasive bladder cancer (MIBC). Response assessment after NAC is important but suboptimal using CT. We assessed MRI without vs. with intravenous contrast (biparametric [BP] vs. multiparametric [MP]) for identifying residual disease on cystectomy and explored its prognostic role.

METHODS

Consecutive MIBC patients that underwent NAC, MRI, and cystectomy between January 2000-November 2022 were identified. Two radiologists reviewed BP-MRI (T2 + DWI) and MP-MRI (T2 + DWI + DCE) for residual tumor. Diagnostic performances were compared using receiver operating characteristic curve analysis. Kaplan-Meier curves and Cox proportional-hazards models were used to evaluate association with disease-free survival (DFS).

RESULTS

61 patients (36 men and 25 women; median age 65 years, interquartile range 59-72) were included. After NAC, no residual disease was detected on pathology in 19 (31.1%) patients. BP-MRI was more accurate than MP-MRI for detecting residual disease after NAC: area under the curve = 0.75 (95% confidence interval (CI), 0.62-0.85) vs. 0.58 (95% CI, 0.45-0.70; p = 0.043). Sensitivity were identical (65.1%; 95% CI, 49.1-79.0) but specificity was higher in BP-MRI compared with MP-MRI for determining residual disease: 77.8% (95% CI, 52.4-93.6) vs. 38.9% (95% CI, 17.3-64.3), respectively. Positive BP-MRI and residual disease on pathology were both associated with worse DFS: hazard ratio (HR) = 4.01 (95% CI, 1.70-9.46; p = 0.002) and HR = 5.13 (95% CI, 2.66-17.13; p = 0.008), respectively. Concordance between MRI and pathology results was significantly associated with DFS. Concordant positive (MRI+/pathology+) patients showed worse DFS than concordant negative (MRI-/pathology-) patients (HR = 8.75, 95% CI, 2.02-37.82; p = 0.004) and compared to the discordant group (MRI+/pathology- or MRI-/pathology+) with HR = 3.48 (95% CI, 1.39-8.71; p = 0.014).

CONCLUSION

BP-MRI was more accurate than MP-MRI for identifying residual disease after NAC. A negative BP-MRI was associated with better outcomes, providing complementary information to pathological assessment of cystectomy specimens.

Induction therapy with ipilimumab and nivolumab followed by consolidative chemoradiation as organ-sparing treatment in urothelial bladder cancer: study protocol of the INDIBLADE trial

Introduction

Studies that assessed the efficacy of pre-operative immune checkpoint blockade (ICB) in locally advanced urothelial cancer of the bladder showed encouraging pathological complete response rates, suggesting that a bladder-sparing approach may be a viable option in a subset of patients. Chemoradiation is an alternative for radical cystectomy with similar oncological outcomes, but is still mainly used in selected patients with organ-confined tumors or patients ineligible to undergo radical cystectomy. We propose to sequentially administer ICB and chemoradiation to patients with (locally advanced) muscle-invasive bladder cancer.

Methods

The INDIBLADE trial is an investigator-initiated, single-arm, multicenter phase 2 trial. Fifty patients with cT2-4aN0-2M0 urothelial bladder cancer will be treated with ipilimumab 3 mg/kg on day 1, ipilimumab 3 mg/kg plus nivolumab 1 mg/kg on day 22, and nivolumab 3 mg/kg on day 43 followed by chemoradiation. The primary endpoint is the bladder-intact event-free survival (BI-EFS). Events include: local or distant recurrence, salvage cystectomy, death and switch to platinum-based chemotherapy. We will also evaluate the potential of multiparametric magnetic resonance imaging of the bladder to identify non-responders, and we will assess the clearance of circulating tumor DNA as a biomarker for ICB treatment response.

Discussion

This is the first trial in which the efficacy of induction combination ICB followed by chemoradiation is being evaluated to provide bladder-preservation in patients with (locally advanced) urothelial bladder cancer.

Clinical Trial Registration

The INDIBLADE trial was registered on clinicaltrials.gov on January 21, 2022 (NCT05200988).

Predicting Recurrence of Non-Muscle-Invasive Bladder Cancer: Current Techniques and Future Trends

Bladder cancer (BC) is the 10th most common cancer globally and has a high mortality rate if not detected early and treated promptly. Non-muscle-invasive BC (NMIBC) is a subclassification of BC associated with high rates of recurrence and progression. Current tools for predicting recurrence and progression on NMIBC use scoring systems based on clinical and histopathological markers. These exclude other potentially useful biomarkers which could provide a more accurate personalized risk assessment. Future trends are likely to use artificial intelligence (AI) to enhance the prediction of recurrence in patients with NMIBC and decrease the use of standard clinical protocols such as cystoscopy and cytology. Here, we provide a comprehensive survey of the most recent studies from the last decade (N = 70 studies), focused on the prediction of patient outcomes in NMIBC, particularly recurrence, using biomarkers such as radiomics, histopathology, clinical, and genomics. The value of individual and combined biomarkers is discussed in detail with the goal of identifying future trends that will lead to the personalized management of NMIBC.

The role of radiomics with machine learning in the prediction of muscle-invasive bladder cancer: A mini review

Bladder cancer is a common malignant tumor in the urinary system. Depending on whether bladder cancer invades muscle tissue, it is classified into non-muscle-invasive bladder cancer (NMIBC) and muscle-invasive bladder cancer (MIBC). It is crucial to accurately diagnose the muscle invasion of bladder cancer for its clinical management. Although imaging modalities such as CT and multiparametric MRI play an important role in this regard, radiomics has shown great potential with the development and innovation of precision medicine. It features outstanding advantages such as non-invasive and high efficiency, and takes on important significance in tumor assessment and laor liberation. In this article, we provide an overview of radiomics in the prediction of muscle-invasive bladder cancer and reflect on its future trends and challenges.

VI-RADS score system - A primer for urologists

Bladder cancer (BCa) is one of the most common cancers worldwide and is also considered to be one of the most relapsing and aggressive neoplasms. About 30% of patients will present with muscle invasive disease, which is associated with a higher risk for metastatic disease. The aim of this article is to review the state of art imaging in Radiology, while providing a complete guide to urologists, with case examples, for the rationale of the development of the Vesical Imaging Reporting and Data System (VI-RADS), a scoring system emphasizing a standardized approach to multiparametric Magnetic Resonance Imaging (mpMRI) acquisition, interpretation, and reporting for BCa. Also, we examine relevant external validation studies and the consolidated literature of mpMRI for bladder cancer. In addition, this article discusses some of the potential clinical implications of this scoring system for disease management and follow-up.

Radiologic Diagnosis and Staging of Bladder Cancer: An Update

Although cystoscopic biopsy is the standard of care for initial diagnosis and local staging of bladder cancer, radiologic imaging plays a major role in identifying local invasion, nodal status, distant metastasis, and posttreatment surveillance. Recent development of the Vesical Imaging-Reporting and Data System for interpretation of multiparametric magnetic resonance imaging of the bladder has expanded the role diagnostic imaging in the management of bladder cancer. This article reviews multimodality imaging appearances, staging, and differential diagnosis of bladder cancer.

Biparametric magnetic resonance imaging assessment for detection of muscle-invasive bladder cancer: a systematic review and meta-analysis

OBJECTIVES

To investigate if removing DCE from the Vesical Imaging Reporting and Data System (VI-RADS) influences the diagnostic accuracy of muscle-invasive bladder cancer (MIBC). We also explored using different reference standards on the MRI diagnostic performance.

METHODS

We searched the Cochrane Library, Embase, and PubMed databases to June 26, 2021. Pooled biparametric MRI (bpMRI, T2WI+DWI) and multiparametric MRI (mpMRI, T2WI+DWI+DCE) sensitivities and specificities and the diagnostic performances of these methods for MIBC were compared using different reference standards.

RESULTS

Seventeen studies with 2344 patients were finally included, of which 7 studies, including 1041 patients, reported the diagnostic performance of bpMRI. VI-RADS showed sensitivities and specificities of 0.91 (95% CI 0.87-0.94) and 0.86 (95% CI 0.77-0.91) at cutoff scores of 3, and 0.85 (95% CI 0.77-0.90) and 0.93 (95% CI 0.89-0.96) at cutoff scores of 4. BpMRI showed sensitivities and specificities of 0.90 (95% CI 0.69-0.97) and 0.90 (95% CI 0.81-0.95), and 0.84 (95% CI 0.78-0.88) and 0.97 (95% CI 0.87-0.99), respectively, for cutoff scores of 3 and 4. The sensitivities of bpMRI vs mpMRI for MIBC were not significantly different, but bpMRI was more specific than mpMRI at cutoff scores of 3 (p = 0.02) and 4 (p = 0.02). The VI-RADS studies using primary transurethral resection of bladder tumors (TURBT) as the reference standard had significantly higher sensitivities (p < 0.001) than those using secondary TURBT or radical cystectomy as the reference.

DATA CONCLUSION

BpMRI and conventional VI-RADS had similar diagnostic efficacies for MIBC. Since MRI overestimated MIBC diagnoses using primary TURBT as the reference standard, we recommend using secondary TURBT as the reference standard.

KEY POINTS

• Biparametric MRI without DCE had similar diagnostic efficacies for MIBC compared with conventional VI-RADS. • The sensitivity of VI-RADS was overestimated when referring to the primary TURBT results. • Biparametric MRI comprised of T2WI and DWI could be used for detecting MIBC in clinical practice.

Diagnostic accuracy of vesical imaging-reporting and data system (VI-RADS) for the detection of muscle-invasive bladder cancer: a meta-analysis

PURPOSE

Vesical Imaging-Reporting and Data System (VI-RADS) was proposed and considered as a standardized reporting criterion for bladder magnetic resonance imaging (MRI). VI-RADS could suggest the likelihood of muscle invasion based on the multiparametric MRI (mp-MRI) findings which contain five-point scores. The current study is designed to comprehensively and systematically evaluate the diagnostic performance of VI-RADS (score 3 and 4) for predicting muscle invasion.

METHODS

The Cochrane Library, Embase, and PubMed were searched comprehensively from inception to October 2021.

RESULTS

Finally, 19 studies incorporating 2900 patients were enrolled. The pooled sensitivity and specificity of VI-RADS 3 for predicting muscle invasion were 0.92 (95%CI 0.89-0.94) and 0.82 (95%CI 0.76-0.87), respectively. The pooled sensitivity and specificity of VI-RADS 4 were 0.78 (95%CI 0.72-0.83) and 0.96 (95%CI 0.93-0.97), respectively. And the area under the curve (AUCs) of VI-RADS 3 and 4 were all 0.94 (95%CI 0.92-0.96). No significant publication biases were not observed for VI-RADS 3 (P = 0.74) and 4 (P = 0.57).

CONCLUSION

The VI-RADS reveals a good diagnostic performance for predicting muscle invasive in bladder cancer, which also has good clinical utilities and applicability. And VI-RADS 3 and 4 as cutoff values provide similar overall diagnostic and could be selectively applied individually. Prospective studies with a large scale are further required to validate the accuracy of the VI-RADS score.

Study Progress of Noninvasive Imaging and Radiomics for Decoding the Phenotypes and Recurrence Risk of Bladder Cancer

Urinary bladder cancer (BCa) is a highly prevalent disease among aged males. Precise diagnosis of tumor phenotypes and recurrence risk is of vital importance in the clinical management of BCa. Although imaging modalities such as CT and multiparametric MRI have played an essential role in the noninvasive diagnosis and prognosis of BCa, radiomics has also shown great potential in the precise diagnosis of BCa and preoperative prediction of the recurrence risk. Radiomics-empowered image interpretation can amplify the differences in tumor heterogeneity between different phenotypes, i.e., high-grade vs. low-grade, early-stage vs. advanced-stage, and nonmuscle-invasive vs. muscle-invasive. With a multimodal radiomics strategy, the recurrence risk of BCa can be preoperatively predicted, providing critical information for the clinical decision making. We thus reviewed the rapid progress in the field of medical imaging empowered by the radiomics for decoding the phenotype and recurrence risk of BCa during the past 20 years, summarizing the entire pipeline of the radiomics strategy for the definition of BCa phenotype and recurrence risk including region of interest definition, radiomics feature extraction, tumor phenotype prediction and recurrence risk stratification. We particularly focus on current pitfalls, challenges and opportunities to promote massive clinical applications of radiomics pipeline in the near future.

A nomogram combined with radiomics features, albuminuria, and metabolic syndrome to predict the risk of myometrial invasion of bladder cancer

Background

To establish a preoperative prediction model of myometrial invasion of bladder cancer (BC) based on the radiomics characteristics of multi-parameter thin-slice enhanced computed tomography (CT) imaging.

Methods

Data from 100 patients with BC were analyzed retrospectively. The patients were divided into two groups: muscular invasive BC and non-muscular invasive BC. The tumor region was segmented from enhanced CT images (arterial- and venous-phase calibration maps) of all patients using Slicer-3D software. We extracted 1,223 texture features from tumor image data based on the shape and gray-level co-occurrence matrix, gray size region matrix, gray run-length matrix, adjacent gray difference matrix, and gray correlation matrix. The patients were randomly divided into a training group (n=70) and a verification group (n=30) in a 7:3 ratio. Interclass correlation coefficients >0.75, least absolute shrinkage, and selection operator regression were used for feature selection. The prediction model was established by combining Rad-score, independent clinical factors, and support vector machine (SVM), and a radiomics nomogram was constructed. The nomogram was tested using the consistency index, calibration curve, time-dependent receiver operating characteristic curve, and clinical decision curve to predict the myometrial invasion of the bladder preoperatively.

Results

Six radiomics features that were significantly related to myometrial invasion of BC were selected to construct a predictive model. The area under the curve (AUC) values of training group and verification group based on SVM were 0.898 (95% CI: 0.820–0.976) and 0.702 (95% CI: 0.495–0.909), respectively. Single factor and multiple factor analysis showed that albuminuria (95% CI: 0.243–2.206, P=0.0014) and metabolic syndrome (95% CI: 0.850–2.935, P<0.001) were independent influencing factors of BC myometrial invasion. Clinical factors and 11 radiomics features were used to construct a comprehensive model for predicting the pathological grade of BC (radiomics + clinical). After a comprehensive comparison, we found that the overall effectiveness of the model (radiomics + clinical) was the highest (AUC =0.8457).

Conclusions

Based on the multi-parameter thin-layer enhanced CT radiomics feature can be used as a potential independent predictor of BC myometrial invasion, the model based on parameters can initially quantitatively characterize the risk of myometrial invasion, and has excellent potential for predicting myometrial invasion of BC.

ACR Appropriateness Criteria® Post-Treatment Surveillance of Bladder Cancer: 2021 Update

Urothelial cancer is the second most common cancer, and cause of cancer death, related to the genitourinary tract. The goals of surveillance imaging after the treatment of urothelial cancer of the urinary bladder are to detect new or previously undetected urothelial tumors, to identify metastatic disease, and to evaluate for complications of therapy. For surveillance, patients can be stratified into one of three groups: 1) nonmuscle invasive bladder cancer with no symptoms or additional risk factors; 2) nonmuscle invasive bladder cancer with symptoms or additional risk factors; and 3) muscle invasive bladder cancer. This document is a review of the current literature for urothelial cancer and resulting recommendations for surveillance imaging. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

[French ccAFU guidelines - update 2020-2022: bladder cancer]

OBJECTIVE

- To update French guidelines for the management of bladder cancer specifically non-muscle invasive (NMIBC) and muscle-invasive bladder cancers (MIBC).

METHODS

- A Medline search was achieved between 2018 and 2020, notably regarding diagnosis, options of treatment and follow-up of bladder cancer, to evaluate different references with levels of evidence.

RESULTS

- Diagnosis of NMIBC (Ta, T1, CIS) is based on a complete deep resection of the tumor. The use of fluorescence and a second-look indication are essential to improve initial diagnosis. Risks of both recurrence and progression can be estimated using the EORTC score. A stratification of patients into low, intermediate and high risk groups is pivotal for recommending adjuvant treatment: instillation of chemotherapy (immediate post-operative, standard schedule) or intravesical BCG (standard schedule and maintenance). Cystectomy is recommended in BCG-refractory patients. Extension evaluation of MIBC is based on contrast-enhanced pelvic-abdominal and thoracic CT-scan. Multiparametric MRI can be an alternative. Cystectomy associated with extended lymph nodes dissection is considered the gold standard for non-metastatic MIBC. It should be preceded by cisplatin-based neoadjuvant chemotherapy in eligible patients. An orthotopic bladder substitution should be proposed to both male and female patients with no contraindication and in cases of negative frozen urethral samples; otherwise transileal ureterostomy is recommended as urinary diversion. All patients should be included in an Early Recovery After Surgery (ERAS) protocol. For metastatic MIBC, first-line chemotherapy using platin is recommended (GC or MVAC), when performans status (PS <1) and renal function (creatinine clearance >60 mL/min) allow it (only in 50% of cases). In second line treatment, immunotherapy with pembrolizumab demonstrated a significant improvement in overall survival.

CONCLUSION

- These updated French guidelines will contribute to increase the level of urological care for the diagnosis and treatment of patients diagnosed with NMIBC and MIBC.

Diagnostic performance of contrast-enhanced dynamic and diffusion-weighted MR imaging in the assessment of tumor response to neoadjuvant therapy in muscle-invasive bladder cancer

OBJECTIVES

To evaluate the diagnostic performance of DCE MRI and DWI in the assessment of pathologic complete response (pCR) after neoadjuvant chemotherapy (NAC) in patients with muscle-invasive bladder cancer (MIBC).

METHODS

This prospective study included 90 patients with MIBC who finished NAC. Two radiologists independently assessed MRI for the determination of semi-quantitative parameters (wash-in rate and wash-out rate) and apparent diffusion coefficient (ADC) value. The correlation between pCR and wash-in rate, wash-out rate, ADC value were analyzed. The area under the ROC curve (AUC) was used to evaluate the diagnostic performance for detecting pCR. Inter-reader agreement was assessed using the ICC statistics.

RESULTS

On cystectomy specimens, pCR was confirmed in (43.3%, 39/90). pCR is negatively correlated with wash-out rate (r = - 0.701, p = 0.01) and ADC value (r = - 0.621, p = 0.01). ADC value is positively correlated with wash-out rate (r = 0.631, p = 0.001). The diagnostic accuracy of ADC value (cut-off value: 0.911 × 10^-3mm²/s) and wash-out rate (cut-off value: 0.677 min^-1) in the identification of pCR was (92% for reader 1, 91% for reader 2), and (90% for reader 1, 88% for reader 2), respectively. The sensitivity, specificity for predicting pCR using ADC value + washout rate cut off values were 95.4%, 97.7% for reader 1, and 96%, 97% for reader 2, respectively. AUC was 0.981 for reader 1, 0.971 for reader 2. The overall reproducibility of the mean ADC value and wash out rate was excellent (ICC = 0.83-0.90). The ICC values for the mean ADC value, washout rate was 0.89 (95% CI 0.84-0.89) and 0.87 (95% CI 0.86-0.91), respectively.

CONCLUSION

Semi-quantitative parameter (wash-out) derived from DCE-MRI and ADC has the potential to assess the tumor's complete pathologic response. The two parameters using together can offer the best possibility to identify complete response to NAC in MIBC.

Imaging of Bladder Cancer: Standard Applications and Future Trends

The evolution in imaging has had an increasing role in the diagnosis, staging and follow up of bladder cancer. Conventional cystoscopy is crucial in the diagnosis of bladder cancer. However, a cystoscopic procedure cannot always depict carcinoma in situ (CIS) or differentiate benign from malignant tumors prior to biopsy. This review will discuss the standard application, novel imaging modalities and their additive role in patients with bladder cancer. Staging can be performed with CT, but distinguishing between T1 and T2 BCa (bladder cancer) cannot be assessed. MRI can distinguish muscle-invasive from non-muscle-invasive tumors with accurate local staging. Vesical Imaging-Reporting and Data System (VI-RADS) score is a new diagnostic modality used for the prediction of tumor aggressiveness and therapeutic response. Bone scintigraphy is recommended in patients with muscle-invasive BCa with suspected bony metastases. CT shows low sensitivity for nodal staging; however, PET (Positron Emission Tomography)/CT is superior and highly recommended for restaging and determining therapeutic effect. PET/MRI is a new imaging technique in bladder cancer imaging and its role is promising. Texture analysis has shown significant steps in discriminating low-grade from high-grade bladder cancer. Radiomics could be a reliable method for quantitative assessment of the muscle invasion of bladder cancer.

Role of magnetic resonance imaging in tumor staging and follow-up for bladder cancer

Urothelial carcinoma of the bladder is a common urologic malignancy. Complex factors, such as local stage, tumor grade, biologic potential, and various conditions, can affect the treatment strategy for bladder cancer. However, the local stage-in particular, the presence or absence of muscle invasion-significantly influences decisions regarding treatment strategy. The role of cystoscopy for screening, diagnosis, and transurethral resection cannot be overlooked. The importance of local staging with magnetic resonance imaging is increasing; magnetic resonance imaging of the bladder is considered a useful staging modality. Moreover, a radiologic reporting system for evaluating and scoring muscle invasion of bladder cancer was recently released. This system is based on multiparametric magnetic resonance imaging and is also expected to be feasible for post-treatment follow-up of bladder cancer. In this review, we discuss the role of magnetic resonance imaging in the local staging of urothelial carcinoma of the urinary bladder and post-treatment imaging. In addition, several technical aspects for obtaining appropriate quality magnetic resonance images of the bladder will be discussed.

Urothelial Carcinoma of the Bladder: Radiologic Perspective

방광암은 비교적 흔히 진단되는 암이며 재발이 흔해 영상의학적 검사에서 흔히 만날 수 있다. 방광암의 정확한 진단과 병기 평가는 어떤 치료를 할 것인지를 정하고 예후를 평가하는데 큰 영향을 미친다. 방광암의 임상적 병기 평가는 요도경유방광종양절제술로 진단과 치료를 겸해서 이루어졌지만, 저평가되는 경우가 흔히 있다. 수술 전 방광암의 위치, 크기, 근육층 침범 유무, 림프절전이, 원격전이, 상부요로 암 유무 등을 영상의학적 검사에서 정확히 진단 및 평가할 수 있다면 더욱 적절히 처치 및 관리를 할 수 있다. 이런 정확한 진단을 위해서는 영상을 판독하는 영상의학과 의사는 먼저 방광암의 임상적인 특징을 잘 알고 있어야 한다. 그리고 영상 검사들의 종류와 특징, 한계를 알고 있어야 한다. 최근 자기공명영상의 발달로 방광 영상의 질 및 방광암의 진단과 평가가 향상되었다. 그리고 방광 이미징 보고 및 데이터시스템이 발표되어 객관적으로 방광암의 근육층 침범 가능성을 평가할 수 있게 되었다. 방광암 치료 종류를 알고 그에 따른 치료 후 변화에는 무엇이 있는지 어떻게 평가하는지도 알아야 하겠다. 이 종설에서는 방광 요로상피세포암의 특징과 다양한 영상의학 검사와 소견에 대해서 알아보고자 한다.

ACR Appropriateness Criteria® Post-Treatment Surveillance of Bladder Cancer

Urothelial cancer is the second most common cancer, and cause of cancer death, related to the genitourinary tract. The goals of surveillance imaging after the treatment of urothelial cancer of the urinary bladder are to detect new or previously undetected urothelial tumors, to identify metastatic disease, and to evaluate for complications of therapy. For surveillance, patients can be stratified into one of three groups: (1) nonmuscle invasive bladder cancer with no symptoms or additional risk factors; (2) nonmuscle invasive bladder cancer with symptoms or additional risk factors; and (3) muscle invasive bladder cancer. This article is a review of the current literature for urothelial cancer and resulting recommendations for surveillance imaging. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

VI-RADS for Bladder Cancer: Current Applications and Future Developments

Bladder cancer (BCa) is among the ten most frequent cancers globally. It is the tumor with the highest lifetime treatment-associated costs, and among the tumors with the heaviest impacts on postoperative quality of life. The purpose of this article is to review the current applications and future perspectives of the Vesical Imaging Reporting and Data System (VI-RADS). VI-RADS is a newly developed scoring system aimed at standardization of MRI acquisition, interpretation, and reporting for BCa. An insight will be given on the BCa natural history, current MRI applications for local BCa staging with assessment of muscle invasiveness, and clinical implications of the score for disease management. Future applications include risk stratification of nonmuscle invasive BCa, surveillance, and prediction and monitoring of therapy response. LEVEL OF EVIDENCE: 3 TECHNICAL EFFICACY STAGE: 2.

French ccAFU guidelines – Update 2018–2020: Bladder cancer

Objective

To propose updated French guidelines for non-muscle invasive (NMIBC) and muscle-invasive (MIBC) bladder cancers.

Methods

A Medline search was achieved between 2015 and 2018, as regards diagnosis, options of treatment and follow-up of bladder cancer, to evaluate different references with levels of evidence.

Results

Diagnosis of NMIBC (Ta, T1, CIS) is based on a complete deep resection of the tumor. The use of fluorescence and a second-look indication are essential to improve initial diagnosis. Risks of both recurrence and progression can be estimated using the EORTC score. A stratification of patients into low, intermediate and high risk groups is pivotal for recommending adjuvant treatment: instillation of chemotherapy (immediate post-operative, standard schedule) or intravesical BCG (standard schedule and maintenance). Cystectomy is recommended in BCG-refractory patients. Extension evaluation of MIBC is based on contrast-enhanced pelvic-abdominal and thoracic CT-scan. Multiparametric MRI can be an alternative. Cystectomy associated with extended lymph nodes dissection is considered the gold standard for non-metastatic MIBC. It should be preceded by cisplatin-based neoadjuvant chemotherapy in eligible patients. An orthotopic bladder substitution should be proposed to both male and female patients with no contraindication and in cases of negative frozen urethral samples; otherwise transileal ureterostomy is recommended as urinary diversion. All patients should be included in an Early Recovery After Surgery (ERAS) protocol. For metastatic MIBC, first-line chemotherapy using platin is recommended (GC or MVAC), when performans status (PS < 1) and renal function (creatinine clearance > 60 mL/min) allow it (only in 50 % of cases). In second line treatment, immunotherapy with pembrolizumab demonstrated a significant improvement in overall survival.

Conclusion

These updated French guidelines will contribute to increase the level of urological care for the diagnosis and treatment for NMIBC and MIBC.

Diagnostic Performance of Vesical Imaging Reporting and Data System for the Prediction of Muscle-invasive Bladder Cancer: A Systematic Review and Meta-analysis

CONTEXT

A noninvasive multiparametric magnetic resonance imaging (MRI)-based scoring system for predicting muscle-invasive bladder cancer (MIBC), the "Vesical Imaging Reporting and Data System" (VI-RADS), was recently developed by an international multidisciplinary panel. Since then, a few studies evaluating the value of VI-RADS for predicting MIBC have been published.

OBJECTIVE

To review the diagnostic performance of VI-RADS for the prediction of MIBC.

EVIDENCE ACQUISITION

PubMed and EMBASE databases were searched up to November 10, 2019. We included diagnostic accuracy studies using VI-RADS to predict MIBC using cystectomy or transurethral resection as the reference standard. Methodological quality was evaluated with Quality Assessment of Diagnostic Accuracy Studies-2. Sensitivity and specificity were pooled and plotted using hierarchical summary receiver operating characteristics (HSROC) modeling. Meta-regression analyses were done to explore heterogeneity.

EVIDENCE SYNTHESIS

Six studies (1770 patients) were included. Pooled sensitivity and specificity were 0.83 (95% confidence interval [CI] 0.70-0.90) and 0.90 (95% CI 0.83-0.95), and the area under the HSROC curve was 0.94 (95% CI 0.91-0.95). Heterogeneity was present among the studies (Q = 29.442, p <  0.01; I² = 87.93%, and 90.99% for sensitivity and specificity). Meta-regression analyses showed that the number of patients (>205 vs ≤205), magnetic field strength (3 vs 1.5 T), T2-weighted image slice thickness (3 vs 4 mm), and VI-RADS cutoff score (≥3 vs ≥4) were significant factors affecting heterogeneity (p ≤  0.03).

CONCLUSIONS

VI-RADS shows good sensitivity and specificity for determining MIBC. Technical factors associated with MRI acquisition and cutoff scores need to be taken into consideration as they may affect performance.

PATIENT SUMMARY

A recently established noninvasive magnetic resonance imaging-based scoring system shows good diagnostic performance in detecting muscle-invasive bladder cancer.

MRI of Bladder Cancer: Local and Nodal Staging

Accurate staging of bladder cancer (BC) is critical, with local tumor staging directly influencing management decisions and affecting prognosis. However, clinical staging based on clinical examination, including cystoscopy and transurethral resection of bladder tumor (TURBT), often understages patients compared to final pathology at radical cystectomy and lymph node (LN) dissection, mainly due to underestimation of the depth of local invasion and the presence of LN metastasis. MRI has now become established as the modality of choice for the local staging of BC and can be additionally utilized for the assessment of regional LN involvement and tumor spread to the pelvic bones and upper urinary tract (UUT). The recent development of the Vesical Imaging-Reporting and Data System (VI-RADS) recommendations has led to further improvements in bladder MRI, enabling standardization of image acquisition and reporting. Multiparametric magnetic resonance imaging (mpMRI) incorporating morphological and functional imaging has been proven to further improve the accuracy of primary and recurrent tumor detection and local staging, and has shown promise in predicting tumor aggressiveness and monitoring response to therapy. These sequences can also be utilized to perform radiomics, which has shown encouraging initial results in predicting BC grade and local stage. In this article, the current state of evidence supporting MRI in local, regional, and distant staging in patients with BC is reviewed. LEVEL OF EVIDENCE: 3 TECHNICAL EFFICACY STAGE: 2 J. Magn. Reson. Imaging 2020;52:649-667.

Elaboration of a multimodal MRI-based radiomics signature for the preoperative prediction of the histological subtype in patients with non-small-cell lung cancer

BACKGROUND

Non-invasive discrimination between lung squamous cell carcinoma (LUSC) and lung adenocarcinoma (LUAD) subtypes of non-small-cell lung cancer (NSCLC) could be very beneficial to the patients unfit for the invasive diagnostic procedures. The aim of this study was to investigate the feasibility of utilizing the multimodal magnetic resonance imaging (MRI) radiomics and clinical features in classifying NSCLC. This retrospective study involved 148 eligible patients with postoperative pathologically confirmed NSCLC. The study was conducted in three steps: (1) feature extraction was performed using the online freely available package with the multimodal MRI data; (2) feature selection was performed using the Student's t test and support vector machine (SVM)-based recursive feature elimination method with the training cohort (n = 100), and the performance of these selected features was evaluated using both the training and the validation cohorts (n = 48) with a non-linear SVM classifier; (3) a Radscore model was then generated using logistic regression algorithm; (4) Integrating the Radscore with the semantic clinical features, a radiomics-clinical nomogram was developed, and its overall performance was evaluated with both cohorts.

RESULTS

Thirteen optimal features achieved favorable discrimination performance with both cohorts, with area under the curve (AUC) of 0.819 and 0.824, respectively. The radiomics-clinical nomogram integrating the Radscore with the independent clinical predictors exhibited more favorable discriminative power, with AUC improved to 0.901 and 0.872 in both cohorts, respectively. The Hosmer-Lemeshow test and decision curve analysis results furtherly showed good predictive precision and clinical usefulness of the nomogram.

CONCLUSION

Non-invasive histological subtype stratification of NSCLC can be done favorably using multimodal MRI radiomics features. Integrating the radiomics features with the clinical features could further improve the performance of the histological subtype stratification in patients with NSCLC.

Multiparametric MRI for Bladder Cancer: Validation of VI-RADS for the Detection of Detrusor Muscle Invasion

Background The Vesical Imaging-Reporting and Data System (VI-RADS) scoring system was created in 2018 to standardize imaging and reporting of bladder cancer staging with multiparametric MRI. The system provides a five-point VI-RADS score, which suggests the likelihood of detrusor muscle invasion. Muscle-invasive disease carries a worse prognosis and requires radical surgery. Purpose To determine the performance of the VI-RADS score in detecting muscle-invasive bladder cancer in a cohort of patients undergoing multiparametric MRI before surgery. Materials and Methods In this retrospective study, a total of 340 patients with bladder cancer were identified from a database of consecutive patients undergoing multiparametric MRI from November 2011 to August 2018. The tumor with the largest burden was selected in those patients with multifocal tumors. Bladder tumors were retrospectively categorized according to the VI-RADS five-point scoring system by two readers, independently and in consensus, who were blinded to histologic findings. The VI-RADS score was compared with postoperative pathology for each tumor, and the performance of VI-RADS for determining detrusor muscle invasion was analyzed by using the Cochran-Armitage test. Results Among the 340 patients, there were 296 men and 44 women; the median age was 64.0 years (interquartile range [IQR], 57.0-87.0 years). Of 340 tumors, 255 (75.0%) were verified as non-muscle-invasive and 85 (25.0%) as muscle-invasive bladder cancer. Both the VI-RADS score and its components were associated with muscle-invasive condition (P < .001). The area under the receiver operating characteristic curve for VI-RADS for muscle invasion was 0.94 (95% confidence interval [CI]: 0.90, 0.98). The sensitivity and specificity of a VI-RADS score of 3 or greater were 87.1% (95% CI: 78%, 93%) and 96.5% (95% CI: 93%, 98%), respectively. Conclusion The Vesical Imaging-Reporting and Data System score effectively defines the likelihood of detrusor muscle invasion in bladder cancer and should be considered for evaluation of tumors prior to surgery. © RSNA, 2019 Online supplemental material is available for this article. See also the editorial by Margolis and Hu in this issue.

A predictive nomogram for individualized recurrence stratification of bladder cancer using multiparametric MRI and clinical risk factors

BACKGROUND

Preoperative prediction of bladder cancer (BCa) recurrence risk is critical for individualized clinical management of BCa patients.

PURPOSE

To develop and validate a nomogram based on radiomics and clinical predictors for personalized prediction of the first 2 years (TFTY) recurrence risk.

STUDY TYPE

Retrospective.

POPULATION

Preoperative MRI datasets of 71 BCa patients (34 recurrent) were collected, and divided into training (n = 50) and validation cohorts (n = 21).

FIELD STRENGTH/SEQUENCE

3.0T MRI/T₂ -weighted (T₂ W), multi-b-value diffusion-weighted (DW), and dynamic contrast-enhanced (DCE) sequences.

ASSESSMENT

Radiomics features were extracted from the T₂ W, DW, apparent diffusion coefficient, and DCE images. A Rad_Score model was constructed using the support vector machine-based recursive feature elimination approach and a logistic regression model. Combined with the important clinical factors, including age, gender, grade, and muscle-invasive status (MIS) of the archived lesion, tumor size and number, surgery, and image signs like stalk and submucosal linear enhancement, a radiomics-clinical nomogram was developed, and its performance was evaluated in the training and the validation cohorts. The potential clinical usefulness was analyzed by the decision curve.

STATISTICAL TESTS

Univariate and multivariate analyses were performed to explore the independent predictors for BCa recurrence prediction.

RESULTS

Of the 1872 features, the 32 with the highest area under the curve (AUC) of receiver operating characteristic were selected for the Rad_Score calculation. The nomogram developed by two independent predictors, MIS and Rad_Score, showed good performance in the training (accuracy 88%, AUC 0.915, P << 0.01) and validation cohorts (accuracy 80.95%, AUC 0.838, P = 0.009). The decision curve exhibited when the risk threshold was larger than 0.3, more benefit was observed by using the radiomics-clinical nomogram than using the radiomics or clinical model alone.

DATA CONCLUSION

The proposed radiomics-clinical nomogram has potential in the preoperative prediction of TFTY BCa recurrence.

LEVEL OF EVIDENCE

3 Technical Efficacy: Stage 3 J. Magn. Reson. Imaging 2019;50:1893-1904.

RETRACTED: Recommandations françaises du Comité de Cancérologie de l’AFU — Actualisation 2018—2020 : tumeurs de la vessie French ccAFU guidelines — Update 2018—2020: Bladder cancer

This article has been retracted: please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy). Cet article est retiré de la publication à la demande des auteurs car ils ont apporté des modifications significatives sur des points scientifiques après la publication de la première version des recommandations. Le nouvel article est disponible à cette adresse: doi:10.1016/j.purol.2019.01.006. C’est cette nouvelle version qui doit être utilisée pour citer l’article. This article has been retracted at the request of the authors, as it is not based on the definitive version of the text because some scientific data has been corrected since the first issue was published. The replacement has been published at the doi:10.1016/j.purol.2019.01.006. That newer version of the text should be used when citing the article.

Multiparametric Magnetic Resonance Imaging for Bladder Cancer: Development of VI-RADS (Vesical Imaging-Reporting And Data System)

CONTEXT

Management of bladder cancer (BC) is primarily driven by stage, grade, and biological potential. Knowledge of each is derived using clinical, histopathological, and radiological investigations. This multimodal approach reduces the risk of error from one particular test, but may present a staging dilemma when results conflict. Multiparametric magnetic resonance imaging (mpMRI) may improve patient care through imaging of the bladder with better resolution of the tissue planes than computed tomography and without radiation exposure.

OBJECTIVE

To define a standardized approach to imaging and reporting mpMRI for BC, by developing a VI-RADS score.

EVIDENCE ACQUISITION

We created VI-RADS (Vesical Imaging-Reporting And Data System) through consensus using existing literature.

EVIDENCE SYNTHESIS

We describe standard imaging protocols and reporting criteria (including size, location, multiplicity, and morphology) for bladder mpMRI. We propose a five-point VI-RADS score, derived using T2-weighted MRI, diffusion-weighted imaging, and dynamic contrast enhancement, which suggests the risks of muscle invasion. We include sample images used to understand VI-RADS.

CONCLUSIONS

We hope that VI-RADS will standardize reporting, facilitate comparisons between patients, and in future years, will be tested and refined if necessary. While we do not advocate mpMRI for all patients with BC, this imaging may compliment pathology or reduce radiation-based imaging. Bladder mpMRI may be most useful in patients with non-muscle-invasive cancers, in expediting radical treatment or for determining response to bladder-sparing approaches.

PATIENT SUMMARY

Magnetic resonance imaging (MRI) scans for bladder cancer are becoming more common and may provide accurate information that helps improve patient care. Here, we describe a standardized reporting criterion for bladder MRI. This should improve communication between doctors and allow better comparisons between patients.

A glance at imaging bladder cancer

Purpose

Early and accurate diagnosis of Bladder cancer (BCa) will contribute extensively to the management of the disease. The purpose of this review was to briefly describe the conventional imaging methods and other novel imaging modalities used for early detection of BCa and outline their pros and cons.

Methods

Literature search was performed on Pubmed, PMC, and Google scholar for the period of January 2014 to February 2018 and using such words as "bladder cancer, bladder tumor, bladder cancer detection, diagnosis and imaging".

Results

A total of 81 published papers were retrieved and are included in the review. For patients with hematuria and suspected of BCa, cystoscopy and CT are most commonly recommended. Ultrasonography, MRI, PET/CT using ¹⁸F-FDG or ¹¹C-choline and recently PET/MRI using ¹⁸F-FDG also play a prominent role in detection of BCa.

Conclusion

For initial diagnosis of BCa, cystoscopy is generally performed. However, cystoscopy can not accurately detect carcinoma insitu (CIS) and can not distinguish benign masses from malignant lesions. CT is used in two modes, CT and computed tomographic urography (CTU), both for dignosis and staging of BCa. However, they cannot differentiate T1 and T2 BCa. MRI is performed to diagnose invasive BCa and can differentiate muscle invasive bladder carcinoma (MIBC) from non-muscle invasive bladder carcinoma (NMIBC). However, CT and MRI have low sensitivity for nodal staging. For nodal staging PET/CT is preferred. PET/MRI provides better differentiation of normal and pathologic structures as compared with PET/CT. Nonetheless none of the approaches can address all issues related for the management of BCa. Novel imaging methods that target specific biomarkers, image BCa early and accurately, and stage the disease are warranted.

Prospective Pilot Study to Evaluate the Incremental Value of PET Information in Patients With Bladder Cancer Undergoing 18F-FDG Simultaneous PET/MRI

PURPOSE

The aim of this study was to conduct a prospective pilot study comparing the diagnostic performance of MRI alone and F-FDG simultaneous PET/MRI using a diuresis protocol in bladder cancer patients.

METHODS

Twenty-two bladder cancer patients underwent F-FDG PET/MRI, using intravenous furosemide and oral hydration for bladder clearance. A radiologist scored probability of tumor in 3 locations (urinary bladder, pelvic lymph nodes, nonnodal pelvis) using 1- to 3-point scale (1 = negative, 2 = equivocal, 3 = definite tumor). A nuclear medicine physician reviewed fused PET/MRI images, after which scores were reassigned based on combined findings. Follow-up pathologic and imaging data served as reference. Performances of MRI alone and PET/MRI were compared.

RESULTS

Of these patients, 82%, 38%, and 18% were positive for bladder, pelvic nodal, and nonnodal pelvic tumor, respectively. At a score of 3, PET/MRI exhibited greater accuracy for detection of bladder tumor (86% vs 77%), metastatic pelvic lymph nodes (95% vs 76%), and nonnodal pelvic malignancy (100% vs 91%). In the bladder, PET changed the level of suspicion in 36% of patients (50% increased suspicion, 50% decreased suspicion), with 75% of these changes deemed correct based on reference standard. For pelvic lymph nodes, PET changed suspicion in 52% (36% increase, 64% decrease), with 95% of changes deemed correct. For nonnodal pelvis, PET changed suspicion in 9% (100% increase), with 100% deemed correct.

CONCLUSIONS

Additional PET information helped to appropriately determine level of suspicion in multiple anatomic sites for otherwise equivocal findings on MRI alone. Although requiring larger studies, findings suggest a possible role for simultaneous PET/MRI to assist bladder cancer management.

Diffusion-Weighted Genitourinary Imaging

This review article aims to provide an overview on of diffusion-weighted MR imaging (DW-MR imaging) in the urogenital tract. Compared with conventional cross-sectional imaging methods, the additional value of DW-MR imaging in the detection and further characterization of benign and malignant lesions of the kidneys, bladder, prostate, and pelvic lymph nodes is discussed as well as the role of DW-MR imaging in the evaluation of treatment response.