Contemporary role of advanced imaging for bladder cancer staging

MRI as a Tool to Assess Interstitial Cystitis Associated Bladder and Brain Pathologies

Interstitial cystitis/bladder pain syndrome (IC/BPS) is a chronic, often incapacitating condition characterized by pain seeming to originate in the bladder in conjunction with lower urinary tract symptoms of frequency and urgency, and consists of a wide range of clinical phenotypes with diverse etiologies. There are currently no diagnostic tests for IC/BPS. Magnetic resonance imaging (MRI) is a relatively new tool to assess IC/BPS. There are several methodologies that can be applied to assess either bladder wall or brain-associated alterations in tissue morphology and/or pain. IC/BPS is commonly associated with bladder wall hyperpermeability (BWH), particularly in severe cases. Our group developed a contrast-enhanced magnetic resonance imaging (CE-MRI) approach to assess BWH in preclinical models for IC/BPS, as well as for a pilot study for IC/BPS patients. We have also used the CE-MRI approach to assess possible therapies to alleviate the BWH in preclinical models for IC/BPS, which will hopefully pave the way for future clinical trials. In addition, we have used molecular-targeted MRI (mt-MRI) to quantitatively assess BWH biomarkers. Biomarkers, such as claudin-2, may be important to assess and determine the severity of BWH, as well as to assess therapeutic efficacy. Others have also used other MRI approaches to assess the bladder wall structural alterations with diffusion-weighted imaging (DWI), by measuring changes in the apparent diffusion coefficient (ADC), diffusion tensor imaging (DTI), as well as using functional MRI (fMRI) to assess pain and morphological MRI or DWI to assess anatomical or structural changes in the brains of patients with IC/BPS. It would be beneficial if MRI-based diagnostic tests could be routinely used for these patients and possibly used to assess potential therapeutics.

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.

The Role of Imaging in Bladder Cancer Diagnosis and Staging

Bladder cancer (BC) is the most common cancer of the urinary tract in the United States. Imaging plays a significant role in the management of patients with BC, including the locoregional staging and evaluation for distant metastatic disease, which cannot be assessed at the time of cystoscopy and biopsy/resection. We aim to review the current role of cross-sectional and molecular imaging modalities for the staging and restaging of BC and the potential advantages and limitations of each imaging modality. CT is the most widely available and frequently utilized imaging modality for BC and demonstrates good performance for the detection of nodal and visceral metastatic disease. MRI offers potential value for the locoregional staging and evaluation of muscular invasion of BC, which is critically important for prognostication and treatment decision-making. FDG-PET/MRI is a novel hybrid imaging modality combining the advantages of both MRI and FDG-PET/CT in a single-setting comprehensive staging examination and may represent the future of BC imaging evaluation.

Fluciclovine positron emission tomography in the setting of biochemical recurrence following local therapy of prostate cancer

Approximately one in five men will demonstrate biochemical recurrence (BCR) following local therapy for prostate cancer (PCa). Advanced imaging modalities including positron emission tomography (PET) imaging of various radiotracers have become more commonplace to visualize foci of disease recurrence. We performed a systematic review of the literature to describe current evidence in support of 18F-fluciclovine (Axumin) PET imaging in this clinical setting. An English literature search was conducted on PubMed/Medline for original investigations on 18F-fluciclovine PET for PCa. Boolean criteria included the terms: prostate, fluciclovine, FACBC and Axumin. Published articles meeting these criteria and their respective bibliographies and diagnostic modalities were included after review, when appropriate. Our literature review identified 93 articles. Among these, 18 met our inclusion criteria. Evidence suggests 18F-fluciclovine PET imaging is safe, well-tolerated and offers acceptable sensitivity and specificity for the detection of localized intraglandular and extraprostatic PCa foci in the setting of persistence or recurrence after primary treatment. Compared to other available PET radiotracers available, evidence suggests that 18F-fluciclovine may outperform ProstaScint and 11C-choline in this clinical setting. Furthermore, 18F-fluciclovine PET may aid guiding decision-making in regards to salvage therapy planning. Further investigation is warranted to validate these early findings and to further compare this agent to other available radiotracers in this setting.

Comparative sensitivity and specificity of imaging modalities in staging bladder cancer prior to radical cystectomy: a systematic review and meta-analysis

PURPOSE

The detection of lymph node metastases in bladder cancer has a significant impact on treatment decisions. Multiple imaging modalities are available to clinicians including magnetic resonance imaging, computed tomography and positron emission tomography. We aimed to investigate the utility of alternate imaging modalities on pre-cystectomy imaging in bladder cancer for the detection of lymph node metastases.

METHODS

We performed systematic search of Web of Science (including MEDLINE), EMBASE and Cochrane libraries in accordance with the PRISMA statement. Studies comparing lymph node imaging findings with final histopathology were included in our analysis. Sensitivity and specificity data were quantified using patient-based analysis. A true positive was defined as a node-positive patient on imaging and node positive on histopathology. Meta-analysis of studies was performed using a mixed-effects, hierarchical logistic regression model.

RESULTS

Our systematic search identified 35 articles suitable for inclusion. MRI and PET have a higher sensitivity than CT while the specificity of all modalities was similar. The summary MRI sensitivity = 0.60 (95% CI 0.44-0.74) and specificity = 0.91 (95% CI 0.82-0.96). Summary PET/CT sensitivity = 0.56 (95% CI 0.49-0.63) and specificity = 0.92 (95% CI 0.86-0.95). Summary CT sensitivity = 0.40 (95% CI 0.33-0.49) and specificity = 0.92 (95% CI 0.86-0.95).

CONCLUSION

MRI and PET/CT provides superior sensitivity compared to CT for detection of positive lymph nodes in bladder cancer prior to cystectomy. There is variability in the accuracy that current imaging modalities achieve across different studies. A number of other factors impact on detection accuracy and these must be considered.

Lower tract neoplasm: Update of imaging evaluation

Cancers of the lower urinary tract can arise from the bladder, urachus or urethra. Urothelial carcinoma of the bladder (UCB) is the most common of these. The presentation of bladder, urachal and urethral cancers can differ but many result in hematuria as an initial indication. The diagnosis and staging of these cancers often necessitate radiologic imaging often in the form of cross-section CT urography or MR urography. The following article reviews the specific nature of lower tract cancers and their imaging.

Second Opinion Expert Pathology Review in Bladder Cancer: Implications for Patient Care

Objectives. To review bladder specimens referred to our facility for secondary review to determine the frequency and degree of changes in pathological diagnoses, which could affect patient care. Methods. A retrospective review of 246 bladder specimens sent to our pathology department for second opinion pathological review was performed. All consultation specimens were reviewed by a single genitourinary (GU)-subspecialized surgical pathologist. Any changes in the pathological grade, stage, or histological tumor type were noted as well as patient demographic data. Statistical analysis was performed to determine the frequency and type of discrepancies in diagnoses and determine any associations with patient demographic parameters. Results. Secondary pathology consultation of 246 bladder specimens from 233 patients were reviewed and compared with the primary diagnosis. The diagnosis was altered in 91/246 cases (37.0%). The number of cases reviewed per patient and specimen type was not associated with a change in diagnosis ( P = .19; P = .1). Of the cases with a change in diagnosis, 8 (8.8%) changed malignancy status, 46 (50.5%) changed stage, 16 (17.6%) changed tumor type (ie, change from urothelial carcinoma to prostate adenocarcinoma), 16 (17.6%) changed histological variant subtype, and 14 (15.4%) changed grade. There was no association noted between age, gender, or race and changes in diagnosis ( P = .53; P = .41; P = .70). Conclusions. Secondary pathology review with a GU-subspecialized surgical pathologist can change the stage, grade, or histological subtype on bladder biopsy and tumor resection specimens in more than one-third of cases. Age and gender were not associated with the frequency of change in diagnosis on consultation review.

Advances in medical imaging for the diagnosis and management of common genitourinary cancers

Medical imaging of the 3 most common genitourinary (GU) cancers-prostate adenocarcinoma, renal cell carcinoma, and urothelial carcinoma of the bladder-has evolved significantly during the last decades. The most commonly used imaging modalities for the diagnosis, staging, and follow-up of GU cancers are computed tomography, magnetic resonance imaging (MRI), and positron emission tomography (PET). Multiplanar multidetector computed tomography and multiparametric MRI with diffusion-weighted imaging are the main imaging modalities for renal cell carcinoma and urothelial carcinoma, and although multiparametric MRI is rapidly becoming the main imaging tool in the evaluation of prostate adenocarcinoma, biopsy is still required for diagnosis. Functional and molecular imaging using 18-fluorodeoxyglucose-PET and sodium fluoride-PET are essential for the diagnosis, and especially follow-up, of metastatic GU tumors. This review provides an overview of the latest advances in the imaging of these 3 major GU cancers.

Clinical and multiparametric MRI signatures of granulomatous prostatitis

PURPOSE

The purpose of the study is to differentiate granulomatous prostatitis (GP) from high-grade prostate cancer (PCa) based on clinical findings and imaging characteristics on multiparametric MRI (MP-MRI).

METHODS

Pathology from patients undergoing MRI/US fusion-guided prostate biopsies between 2014 and 2015 was reviewed. Five patients with biopsy proven GP were identified as well as 15 patients with biopsy-proven Gleason score ≥4 + 3 = 7 PCa. Patients were matched for age, serum PSA level, and prebiopsy-assigned MP-MRI cancer suspicion scores. MP-MRI studies were reviewed to identify findings that would differentiate GP from PCa in patients who had equally high suspicion scores based upon imaging characteristics.

RESULTS

All five patients with GP on MR/US fusion-targeted biopsies were assigned a PIRADS 4 or 5 suspicion score. There were equally high suspicion scores on MP-MRI for both groups (p = 0.57). Re-evaluation of the MRI characteristics of the 5 GP patients and 15 matched controls who had pathologically proven Gleason score ≥4 + 3 = 7 PCa on targeted biopsy demonstrated statistically lower mean ADC values within the index targeted lesion for PCa vs. GP (p = 0.002) Qualitatively, no patients with GP on biopsy had imaging evidence of higher-staged disease, while 33% of patients in the high-risk PCa cohort demonstrated at least one high-stage feature (p = 0.003).

CONCLUSION

Patients with GP routinely have MRIs with moderate to high levels of suspicion for harboring PCa. Re-evaluation of these patients' imaging demonstrated characteristics including significantly higher ADC values and absence of high-stage features, which may help differentiate areas of GP from PCa in the future.

Assessing Cancer Progression and Stable Disease After Neoadjuvant Chemotherapy for Organ-confined Muscle-invasive Bladder Cancer

OBJECTIVE

To propose and validate a new approach to stratify clinically staged, organ-confined, muscle-invasive bladder cancer patients (cT2N0M0) who are pathologic non-responders to neoadjuvant chemotherapy (NAC) to better characterize NAC non-response.

METHODS

We retrospectively identified radical cystectomy patients with cT2N0M0 disease at our institution (2005-2014) and in the National Cancer Database (2004-2012) for external validation. Patients were stratified as stable (pT2N0M0) or progressors (>pT2 or pN+). The primary end points were cancer-specific survival (CSS), overall survival (OS), and recurrence-free survival (RFS).

RESULTS

In the institutional cohort, NAC stable patients (n = 17) had better OS (P = .05) and RFS (P = .04) than NAC progressors (n = 50), and had comparable OS (P = .7) and CSS (P = .09) with non-NAC stable patients (n = 27). Multivariable Cox proportional hazard models showed that larger tumor size predicted worse OS (hazard ratio [HR] = 1.20 per centimeter, 95% confidence interval [CI: 1.07, 1.35]), CSS (HR = 1.27, 95% CI [1.11, 1.45]), and RFS (HR = 1.24, 95% CI [1.09, 1.42]). Similarly, in the National Cancer Database, NAC stable patients (n = 223) had improved OS (P < .0001) compared with NAC progressors (n = 232) and comparable (P = .4) OS with non-NAC stable patients (n = 950). Multivariable Cox proportional hazard model showed that larger tumor size (HR = 1.03 per centimeter, 95% CI [1.02, 1.03]) and progression (HR = 2.69, 95% CI [2.40, 3.01]) predicted worse OS.

CONCLUSION

Distinct survival outcomes suggest that NAC non-responders should be further stratified into stable disease and progressors. Comparable survival between non-NAC and NAC stable disease patients suggests that NAC stable disease may represent a chemoresistant but more indolent phenotype on the disease spectrum. Moreover, tumor size is an important prognostic biomarker in NAC non-responders. Clinical predictors of disease progression on NAC were not identified, highlighting the need to explore molecular and genomic subtyping determinants of disease progression.

Preoperative Imaging for Clinical Staging Prior to Radical Cystectomy

The importance of patient selection for quality outcomes following radical cystectomy is critical. Clinical staging is one of the key elements necessary for patient selection, and staging relies on accurate preoperative imaging. Many imaging modalities are available and have been utilized for preoperative staging with published operating characteristics. In this update, we review recently published literature for advances in preoperative imaging prior to radical cystectomy.

Complete Tissue Submission to Increase Lymph Node Detection in Pelvic Lymph Node Packets Submitted for Patients Undergoing Radical Prostatectomy and Radical Cystectomy

BACKGROUND

Pelvic lymphadenectomy has prognostic and therapeutic implications in both bladder and prostate cancer. Pelvic lymphadenectomy specimens are fatty and identification of lymph nodes (LNs) can be difficult during the grossing process. We investigated the benefit of a new grossing method requiring entire LN packet submission.

MATERIALS/METHODS

We introduced a new grossing protocol requiring total submission of LN packets for patients undergoing radical prostatectomy (RP) or radical cystectomy (RC). A retrospective review was performed to evaluate clinical and pathologic data for RP (n = 59) and RC (n = 56) cases performed 18 months prior to and 18 months following implementation of the new lymphadenectomy grossing protocol.

RESULTS

For RP and RC cases, significantly more LNs were found when total LN packets were submitted with the new technique: mean 14.1 versus 8.7, and mean 25.2 versus 15.9, respectively ( P = .007, P = .011). For RP cases, there was no significant change in the number of LN packets submitted for evaluation from the operating room ( P = .76). For RC cases, more LNs were found with the new technique despite a significantly fewer number of LN packets sent from the operating room in the cohort that were processed with the new technique: mean 2.2 versus 4.0 LN packets ( P < .001). Significantly more paraffin blocks were required using the new grossing method for both RP and RC: mean 13.53 versus 6.9 and mean 19.0 versus 12.4, respectively ( P < .001, P = .018).

CONCLUSIONS

Submitting all additional fatty tissue after palpable identification of LNs can significantly increase the detection of LNs in RP and RC cases.

Improving Staging in Bladder Cancer: The Increasing Role of Multiparametric Magnetic Resonance Imaging

CONTEXT

In bladder cancer (BCa) patients, accurate local and regional tumor staging is required when planning treatment. Clinical understaging frequently occurs and leads to undertreatment of the disease, with a negative impact on survival. An improvement in staging accuracy could be attained by advances in imaging. Magnetic resonance imaging (MRI) is currently the best imaging technique for locoregional staging for several malignancies because of its superior soft tissue contrast resolution with the advantage of avoiding exposure to ionizing radiation. Important improvements in MRI technology have led to the introduction of multiparametric MRI (mpMRI), which combines anatomic and functional evaluation.

OBJECTIVE

To review the fundamentals of mpMRI in BCa and to provide a contemporary overview of the available data on the role of this emerging imaging technology.

EVIDENCE ACQUISITION

A nonsystematic literature search using the Medline and Cochrane Library databases was performed up to March 2016. Additional articles were retrieved by cross-matching references of selected articles. Only articles reporting complete data with regard to image acquisition protocols, locoregional staging, monitoring response to therapy, and detection of locoregional recurrence after primary treatment in BCa patients were selected.

EVIDENCE SYNTHESIS

Standardization of acquisition and reporting protocols for bladder mpMRI is paramount. Combining anatomic and functional sequences improves the accuracy of local tumor staging compared with conventional imaging alone. Diffusion-weighted imaging may distinguish BCa type and grade. Functional sequences are capable of monitoring response to chemotherapy and radiation therapy. Diffusion-weighted imaging enhanced by lymphotropic nanoparticles showed high accuracy in pelvic lymph node staging compared with conventional cross-sectional imaging.

CONCLUSIONS

In BCa patients, mpMRI appears a promising tool for accurate locoregional staging, predicting tumor aggressiveness and monitoring response to therapy. Further large-scale studies are needed to confirm these findings.

PATIENT SUMMARY

Better imaging through improved technology will improve outcomes in bladder cancer patients. We reviewed the emerging use of multiparametric magnetic resonance imaging for staging and monitoring bladder cancer. Multiparametric magnetic resonance imaging appears more accurate than current methods for local and nodal staging and monitoring tumor response to treatment, but requires further investigation.

Incidental Bladder Cancer Detected on Multiparametric Magnetic Resonance Imaging of the Prostate Gland

The increased use of axial imaging in various fields of medicine has led to an increased frequency of incidental findings, specifically incidental cancer lesions. Hence, as the use of multiparametric magnetic resonance imaging (MP-MRI) for prostate cancer detection, staging, and management becomes more widespread, the potential for additional incidental findings in the pelvis increases. Herein, we report the case of a man on active surveillance for low-grade, early-staged prostate cancer who underwent MP-MRI and was incidentally found to have a high-grade bladder cancer lesion.