Imaging muscle-invasive and metastatic urothelial carcinoma

Association of current molecular subtypes in urothelial carcinoma with patterns of muscularis propria invasion

Urothelial carcinoma is subdivided into luminal (L), basal (B), and p53-wild-type (WT) molecular subtypes, with basal and p53-WT groups showing more aggressive course and poor treatment response, respectively. The literature on molecular subtypes of UC includes a mixture of different stages. We investigated the molecular profile and outcome of pure cohort of muscle invasive bladder carcinoma (MIBC) considering two distinct patterns of muscularis propria (MP) invasion. Forty-three cystectomies harboring stage pT2 were retrospectively identified in 18 years. MP invasion was subclassified into patterns 1 (tumor encasing intact detrusor muscle bundles) and 2 (tumor dissecting/replacing detrusor muscle). Using IHC, B/L phenotypes, p53, and Ki67 were assessed, and survival data was collected. Pattern 1 invasion was noted in 16 (37%) and pattern 2 in 27 (63%), with mean age of pattern 1 being 10 years younger. B/L phenotypes were successfully determined in 83.7%; 48.8% and 34.8% revealed L and B phenotypes, respectively (indeterminate phenotype in 16.4%). Pattern 1 was associated with L phenotype (GATA3 and HER-2 expressions: p = 0.02 & p = 0.04, respectively). Ki67 ≥ 5/10HPF was noted in pattern 2 and B phenotype (p = 0.03). B phenotype showed association with p53-WT (p = 0.007). In median follow-up of 60.7 months, 63.6% of pattern 1 cases were alive without disease compared to 32% of pattern 2 (not significant). A panel of CK20 and GATA3 for luminal and CK5/6 and CK14 for basal subtypes can provide reliable molecular classification in UC. Also, morphology of MIBC can predict the molecular phenotype and the behavior of the UC.

Vesical Imaging Reporting and Data System (VI-RADS): Are the individual MRI sequences equivalent in diagnostic performance of high grade NMIBC and MIBC?

PURPOSE

To investigate the diagnostic performance of the overall Vesical Imaging Reporting and Data System (VI-RADS) score and its individual magnetic resonance imaging (MRI) parameters in assessing grade and muscle invasiveness of bladder cancer (BC).

METHODS

This IRB-approved retrospective, single-center, cross-sectional study included patients with BC wo underwent 3 Tesla preoperative multiparametric (mp)-MRI including T2-weighted (T2w), diffusion weighted imaging (DWI) and dynamic contrast enhanced (DCE) sequences. An independent evaluation according to VI-RADS was performed by two radiologists in separate sessions, blinded to histological findings.

RESULTS

The mean age of 59 included patients was 68.2 (±13.6 standard deviation) years. Among bladder cancer patients, 26 (51%) were identified as high grade and 14 (27.5%) as muscle invasive urothelial carcinomas in histological sections. The area under the curve (AUC) for the overall VI-RADS score to predict muscle invasion was 0.986 (R1) and 0.992 (R2). The AUC to diagnose high grade bladder cancer was 0.908 (R1) and 0.905 (R2). There was no significance difference between the AUC of single parameters (T2w, DWI and DCE) compared to the total VI-RADS score (P > 0.05, respectively). Upon multivariate logistic regression, only the T2w VI-RADS score contributed independently to the diagnosis of high grade and muscle invasive bladder cancer (P = 0.001 (R1) and P = 0.0022 (R2) for high grade cancer; P = 0.0007 (R1) and P = 0.0019 (R2) for muscle invasiveness).

CONCLUSION

VI-RADS provides high diagnostic accuracy to diagnose high grade and muscle invasive BC. Our results suggest, that mp-MRI parameters provide overlapping information and for sake of clinical simplicity, a biparametric, contrast free image acquisition may be approached without sacrificing diagnostic accuracy.

Clinical value of 18FDG PET/MRI in muscle-invasive, locally advanced, and metastatic bladder cancer

OBJECTIVE

Metastatic bladder cancer is an aggressive disease that can often be difficult to diagnose and stage with conventional cross-sectional imaging. The primary objective of this study was to determine the clinical value of fluorine-18 2-fluoro-2-deoxy-D-glucose (¹⁸F-FDG) PET/MRI for surveillance and restaging of patients with muscle-invasive, locally advanced, and metastatic bladder cancer compared to conventional imaging methods.

MATERIALS AND METHODS

This retrospective study enrolled patients with muscle-invasive, locally advanced and metastatic bladder cancer in a single institute evaluated with ¹⁸F-FDG PET/MRI. All patients also underwent conventional imaging with CT. Additional imaging may also have included ¹⁸F-FDG PET/CT (¹⁸F-FDG PET), or sodium fluoride (NaF) PET/CT in some patients. Images were reviewed by a diagnostic radiologist/nuclear medicine physician. Number of lesions and sites of disease were captured and compared between ¹⁸F-FDG PET/MRI and conventional imaging. Lesions were confirmed by sequential imaging or lesion biopsy. All patients were followed for survival.

RESULTS

Fifteen patients (4 for surveillance; 11 for restaging) underwent 34 ¹⁸F-FDG PET/MRI scans. Each patient received a corresponding conventional CT around the time of the ¹⁸F-FDG PET/MRI (median 6 days). The 15 patients (11 male; 4 female) had a median age of 61.5 years (range 37-73) and histologies of urothelial carcinoma (n = 13) and small-cell carcinoma of the bladder (n = 2) diagnosed as stage 4 (n = 13), stage 3 (n = 1), or stage 2 (n = 1). ¹⁸F-FDG PET/MRI detected 82 metastatic malignant lesions involving lymph nodes (n = 22), liver (n = 10), lung (n = 34), soft tissue (n = 12), adrenal glands (n = 1), prostate (n = 1), and bone (n = 2) with a resultant advantage of 36% for lesion visibility in comparison with CT. Serial imaging or biopsy confirmed these lesions as malignant.

CONCLUSION

¹⁸F-FDG PET/MRI can detect metastatic lesions which cannot be identified on conventional CT, and this can allow for better treatment planning and improved disease monitoring during therapy.

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.

[18F]Fluoro-Deoxy-Glucose positron emission tomography to evaluate lymph node involvement in patients with muscle-invasive bladder cancer receiving neoadjuvant pembrolizumab

BACKGROUND

Data regarding the role of positron emission tomography/computed tomography (PET/CT) to stage lymph nodes in patients receiving neoadjuvant immunotherapy before radical cystectomy are lacking. The aim of this study is to evaluate the role of PET/CT to predict the pathologic lymph node involvement (LNI) in patients with MIBC receiving neoadjuvant pembrolizumab within the PURE-01 trial (NCT02736266).

MATERIAL AND METHODS

Three courses of pembrolizumab were administered before radical cystectomy and extended pelvic lymph node dissection in clinical T2-4aN0M0 MIBC based on contrast-enhanced CT scan. LNI was also assessed with PET/CT before and after treatment. PET/CT results were compared with histopathological findings. The ability of baseline and post-therapy PET/CT to evaluate LNI was assessed, and univariate logistic regression analyses were performed.

RESULTS

From February 2017 to August 2019, a total of 108 patients and 105 patients had evaluable baseline and post-pembrolizumab scans, respectively. The sensitivity to detect LNI was 27% and 37.5% for pre- and post-pembrolizumab PET/CT, and specificity was 97% and 98%, respectively. In total, 4 of 7 patients (57%) showing baseline FDG-uptake had LNI vs. 11 of 101 (11%) with no baseline uptake. All but 1 of the 7 patients did not respond to pembrolizumab. Both pre- and post-pembrolizumab PET/CT significantly predicted LNI (P = 0.004 and P < 0.001) at univariate analyses. Our results warrant further validation in larger datasets.

CONCLUSIONS

PET/CT performance does not justify its use in routine practice for cN0 MIBC. However, our preliminary data revealed opportunities for the use of baseline PET/CT, within clinical trials, to optimally select patients with MIBC who are best suited for neoadjuvant immunotherapy strategies. Validation in larger datasets, as well as a cost analysis, are needed.

Current Management of Localized Muscle-Invasive Bladder Cancer: A Consensus Guideline from the Genitourinary Medical Oncologists of Canada

BACKGROUND: Despite recent advances in the management of muscle-invasive bladder cancer (MIBC), treatment outcomes remain suboptimal, and variability exists across current practice patterns. OBJECTIVE: To promote standardization of care for MIBC in Canada by developing a consensus guidelines using a multidisciplinary, evidence-based, patient-centered approach who specialize in bladder cancer. METHODS: A comprehensive literature search of PubMed, Medline, and Embase was performed; and most recent guidelines from national and international organizations were reviewed. Recommendations were made based on best available evidence, and strength of recommendations were graded based on quality of the evidence. RESULTS: Overall, 17 recommendations were made covering a broad range of topics including pathology review, staging investigations, systemic therapy, local definitive therapy and surveillance. Of these, 10 (59% ) were level 1 or 2, 7 (41% ) were level 3 or 4 recommendations. There were 2 recommendations which did not reach full consensus, and were based on majority opinion. This guideline also provides guidance for the management of cisplatin-ineligible patients, variant histologies, and bladder-sparing trimodality therapy. Potential biomarkers, ongoing clinical trials, and future directions are highlighted. CONCLUSIONS: This guideline embodies the collaborative expertise from all disciplines involved, and provides guidance to further optimize and standardize the management of MIBC.

Correlation Between Pain and Nerve Growth Factor Receptor Expression in Patients with Endometriosis Diagnosed by Transvaginal Color Ultrasound and Magnetic Resonance

This paper explores the diagnosis of deep invasive endometriosis through retrospective data analysis, including deep infiltration and magnetic resonance imaging. The literature retrospectively collected data from 21 patients with deep invasive endometriosis who were admitted from 2012 to 2018. The patients were confirmed to have pain and nerve growth factor (NGF) receptor expression levels after operation and underwent vaginal color ultrasound and magnetic resonance imaging before surgery. The diagnostic results of color Doppler ultrasound and magnetic resonance imaging were retrospectively analyzed and compared with the surgical results, and the cumulative site and anatomic abnormalities of the diagnosis of deep invasive endometriosis were analyzed to determine the NGF receptor table. Through research it has been found that deep invasive endometriosis mainly involves the uterine fibula ligament, vagina, uterus rectum, rectum, ureter, and so forth. Patient pain is related to the expression level of NGF receptor, and its magnetic resonance mainly manifests as signals and structural obstacles, irregular thickening of the affected area, or nodular formation and deformation of adjacent tissues and organs. Through research and demonstration of deep invasive endometriosis, transvaginal color ultrasound and magnetic resonance imaging can not only accurately locate the expression levels of pain and NGF receptors, but also show the extent of the lesions, thereby studying pain and NGF receptor expression, which is an important method for preoperative examination and postoperative follow-up.

Multiparametric Magnetic Resonance Imaging as a Noninvasive Assessment of Tumor Response to Neoadjuvant Pembrolizumab in Muscle-invasive Bladder Cancer: Preliminary Findings from the PURE-01 Study

BACKGROUND

In the PURE-01 study, pembrolizumab was given preoperatively before radical cystectomy in clinical T2-4aN0M0 patients. An accurate clinical response assessment may be useful for developing new perioperative strategies in these patients.

OBJECTIVE

To evaluate the association between bladder multiparametric magnetic resonance imaging (mpMRI) findings after pembrolizumab and the pathological complete response (CR; pT0).

DESIGN, SETTING, AND PARTICIPANTS

Patients were staged using bladder mpMRI whereby radiologists were asked to characterize the following parameters: residual disease at T1- and T2-weighted images (step 1: yes/no), presence of hyperintense spots within the bladder wall on diffusion-weighted imaging (step 2: yes/no), and presence of pathological contrast enhancement (step 3: yes/no), before and after three cycles of pembrolizumab. Examinations were internally assessed by two senior radiologists and externally evaluated by a third senior radiologist.

INTERVENTION

To evaluate bladder tumor response after neoadjuvant pembrolizumab, mpMRI was used.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

The primary objective was to predict the pT0 after neoadjuvant pembrolizumab by relying on the mpMRI findings. Cohen's kappa statistics was used to assess interobserver variability. Univariable analyses for pT0 were performed including internal and external post-therapy mpMRI steps.

RESULTS AND LIMITATIONS

From February 2017 to October 2018, 82 patients (164 total mpMRI assessments) were analyzed. The agreement between the internal and external mpMRI assessments after therapy was acceptable (κ values ranging from 0.5 to 0.76). Each mpMRI step was significantly associated with pT0 in both internal and external assessments. In patients with CR/no evidence of residual disease (NED) in all internally evaluated mpMRI steps (N = 37), the pT0 was seen in 23 (62%), compared with 19 of 26 externally evaluated NED patients (73%).

CONCLUSIONS

In post-pembrolizumab muscle-invasive bladder cancer, mpMRI sequence assessment had acceptable interobserver variability and represented the basis for the proposal of a radiological CR/NED status definition predicting the pT0 response to pembrolizumab. After validation of these findings with external datasets, we propose this tool for developing bladder-sparing immunotherapy maintenance therapies.

PATIENT SUMMARY

Assessment of the extent of disease in patients with muscle-invasive bladder cancer using conventional imaging yields serious limitations. In the PURE-01 study, we evaluated the potential of bladder multiparametric magnetic resonance imaging (MRI) to predict the pathological complete response to neoadjuvant pembrolizumab. After validation with larger datasets, the proposed stepwise assessment incorporating multiparametric MRI sequences will be used at our center to develop bladder-sparing approaches in future studies.

Assessing lymph node status in patients with kidney cancer

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

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.

The Role of Computerized Tomography in the Assessment of Perivesical Invasion in Bladder Cancer

Background

The aim of the present study was to identify the contrast patterns of a tumor, and to evaluate the possibility of assessing the invasion of the perivesical fatty tissue in bladder cancer.

Material/Methods

In this study, 26 patients with bladder cancer were included. Multiphasic CT examination was performed to determine the stage of the disease before radical cystectomy.

Results

There were statistically significant differences in tumor and perivesical fatty tissue densities between pre- and post-contrast phases (p<0.05).

Conclusions

Increases in focal density suspected of being invasion of the perivesical fatty tissue can show perivesical invasion with high specificity.