Diagnostic accuracy of C-11 choline and C-11 acetate for lymph node staging in patients with bladder cancer: a systematic review and meta-analysis

Performance of 18F-FDG PET/MRI and its parameters in staging and neoadjuvant therapy response evaluation in bladder cancer

18F-FDG PET/MRI shows potential efficacy in the diagnosis of bladder cancer (BLCA). However, the performance of 18F-FDG PET/MRI in staging and neoadjuvant therapy (NAT) response evaluation for BLCA patients remains elusive. Here, we conduct this study to evaluate the performance of 18F-FDG PET/MRI and its derived parameters for tumor staging and NAT response prediction in BLCA. Forty BLCA patients were retrospectively enrolled to evaluate the performance of 18F-FDG PET/MRI in staging and NAT response prediction in BLCA. The feasibility of using 18F-FDG PET/MRI-related parameters for tumor staging and NAT response evaluation was also analyzed. In conclusion, 18F-FDG PET/MRI is found to show good performance in the BLCA staging and NAT response prediction. Moreover, ΔSUVmean is an efficacious candidate parameter for NAT response prediction. This study highlights that 18F-FDG PET/MRI is a promising imaging approach in the clinical diagnosis and treatment for BLCA.

The evolution of PET imaging in renal, bladder, upper urinary tract urothelial, testicular and penile carcinoma - Today's impact, tomorrow's potential

INTRODUCTION

The advancement of hybrid PET/CT or PET/MRI imaging for non-prostate genitourinary cancers has not experienced the rapid progress of prostate cancer. Nevertheless, these neoplasms are aggressive and reliable imaging plays a pivotal role in enhancing patients' quality of life and prognosis.

AREAS COVERED

the main evidence regarding [18F]FDG and non-[18F]FDG PET/CT or PET/MRI in non-prostate uro-oncological malignancies are summarized and discussed. Moreover, potential future directions concerning PET imaging in these neoplasms are debated, with the aim to stimulate future research projects covering these fields.

EXPERT OPINION

In Renal Cell Carcinoma (RCC), [18F]FDG PET/CT demonstrates varying efficacy in staging, restaging, and prognostic stratification, but PSMA PET/CT is emerging as a potential game-changer, particularly in advanced, high-grade aggressive clear cell RCC. [18F]FDG PET/CT may see an increased use in N and M-staging of bladder cancer, as well as for detecting recurrence and response to neoadjuvant chemotherapy. Preliminary data regarding [68Ga]-FAPI also looks promising in this context. [18F]FDG PET/MRI could be useful for the T-staging of bladder cancer, while upper tract urothelial carcinoma still lacks of molecular imaging literature reports. In testicular and penile cancer [18F]FDG PET/CT has demonstrated its usefulness in several clinical settings, although experiences with non-[18F]FDG radiotracers are lacking.

Vascular Enlargement as a Predictor of Nodal Involvement in Bladder Cancer

In bladder cancer (BC), the evaluation of lymph node (LN) involvement at preoperative imaging lacks specificity. Since neoangiogenesis is paired with lymphatic involvement, this study aims to evaluate the presence of perivesical venous ectasia as an indirect sign of LN involvement, together with other conventional CT findings. All the patients who underwent radical cystectomy (RC) for BC between January 2017 and December 2019 with available preoperative contrast-enhanced CT (CECT) within 1 month before surgery were included. Patients without available pathological reports (and pTNM stage) or who underwent neoadjuvant treatments and palliative RC were excluded. Two readers in blind assessed the nodal shape and hilum, the short axis, and the contrast enhancement of suspicious pelvic LNs, the Largest Venous Diameter (LVD) efferent to the lesion, and the extravesical tumor invasion. In total, 38 patients (33 males) were included: 17 pT2, 17 pT3, 4 pT4; pN+: 20/38. LN short axis > 5 mm, LN enhancement, and LVD > 3 mm were significantly correlated with N+ at pathology. LVD > 3 mm had a significantly higher sensitivity and specificity (≥90%, AUC = 0.949) and was an independent predictor (p = 0.0016).

PET Imaging in Bladder Cancer: An Update and Future Direction

Molecular imaging with positron emission tomography is a powerful tool in bladder cancer management. In this review, we aim to address the current place of the PET imaging in bladder cancer care and offer perspectives on potential future radiopharmaceutical and technological advancements. A special focus is given to the following: the role of [¹⁸F] 2-[18F]fluoro-2-deoxy-D-glucose positron emission tomography in the clinical management of bladder cancer patients, especially for staging and follow-up; treatment guided by [¹⁸F]FDG PET/CT; the role of [¹⁸F]FDG PET/MRI, the other PET radiopharmaceuticals beyond [¹⁸F]FDG, such as [⁶⁸Ga]- or [¹⁸F]-labeled fibroblast activation protein inhibitor; and the application of artificial intelligence.

Targeted Molecular Imaging as a Biomarker in Urologic Oncology

Urologic malignancies constitute a large portion of annually diagnosed cancers. Timely diagnosis, accurate staging, and assessment of tumor heterogeneity are essential to devising the best treatment strategy for individual patients. The high sensitivity of molecular imaging allows for early and sensitive detection of lesions that were not readily detectable using conventional imaging techniques. Moreover, molecular imaging enables the interrogation of molecular processes used in targeted cancer therapies and predicts cancer response to treatment. Here we review the current advancements in molecular imaging of urologic cancers, including prostatic, vesical, renal testicular, and ureteral cancers.

Management of Bladder Cancer Patients with Clinical Evidence of Lymph Node Invasion (cN+)

The purpose of this review is to present the current knowledge about the diagnostic and treatment options for bladder cancer (BCa) patients with clinically positive lymph nodes (cN+). This review shows compaction of CT and MRI performance in preoperative prediction of lymph node invasion (LNI) in BCa patients, along with other diagnostic methods. Most scientific societies do not distinguish cN+ patients in their guidelines; recommendations concern muscle-invasive bladder cancer (MIBC) and differ between associations. The curative treatment that provides the best long-term survival in cN+ patients is a multimodal approach, with a combination of neoadjuvant chemotherapy (NAC) and radical cystectomy (RC) with extended pelvic lymph node dissection (ePLND). The role of adjuvant chemotherapy (AC) remains uncertain; however, emerging evidence indicates comparable outcomes to NAC. Therefore, in cN+ patients who have not received NAC, AC should be implemented. The response to ChT is a crucial prognostic factor for cN+ patients. Recent studies demonstrated the growing importance of immunotherapy, especially in ChT-ineligible patients. Moreover, immunotherapy can be suitable as adjuvant therapy in selected cases. In cN+ patients, the extended template of PLND should be utilized, with the total resected node count being less important than the template. This review is intended to draw special attention to cN+ BCa patients, as the oncological outcomes are significantly worse for this group.

Extent of lymph node dissection and impact on survival in radical cystectomy for advanced bladder cancer

PURPOSE OF REVIEW

In patients with muscle invasive bladder cancer (MIBC) or unresectable non-MIBC, radical cystectomy is routinely combined with bilateral pelvic lymph node dissection (LND) owing to the oncological benefits found in recurrence-free survival (RFS), overall survival (OS) and cancer-specific survival (CSS) compared with radical cystectomy alone. However, the optimal anatomic extent of LND is still unclear.

RECENT FINDINGS

Retrospective studies were consistent in reporting oncological benefits of extended LND over nonextended LND. A recent RCT (the LEA trial) failed to demonstrate any benefit in terms of RFS, CSS and OS of super-extended LND over standard LND. Several confounding factors hindered the interpretation of the results, leaving the question of the right extent for LND still open. Results of a similar study, the SWOG S1011 are, therefore, highly anticipated. This study differed from the LEA study in several aspects but might also turn out to be a negative study.

SUMMARY

There are still no firm data on the oncological benefit brought by more extended LND in patients with MIBC. Survival benefits seem limited, at least in the general population. Other factors could influence the impact of LND on survival, including the administration of adjuvant and neoadjuvant chemotherapies.

Diagnostic accuracy of preoperative lymph node staging of bladder cancer according to different lymph node locations: A multicenter cohort from the European Association of Urology - Young Academic Urologists

BACKGROUND

The preoperative lymph node (LN) staging of bladder cancer (BCa) addresses the subsequent therapeutic strategy and influences patient's prognosis. However, sparce evidence exists regarding the accuracy of conventional cross-sectional imaging, such as computed tomography or magnetic resonance imaging, in correctly detect LN status. We aimed to assess the diagnostic accuracy of conventional cross-sectional imaging in detecting preoperative LN involvement among BCa patients treated with radical cystectomy and pelvic lymph node dissection.

METHODS

We retrospectively analyzed data of 1,104 patients who underwent preoperative LN staging with computed tomography or magnetic resonance imaging and subsequent radical cystectomy with pelvic lymph node dissection for BCa between 1997 and 2017 at three tertiary referral centers. Patients receiving neoadjuvant chemotherapy were excluded. We assessed the concordance between clinical (cN) and pathological LN (pN) status, defined as the accuracy of imaging in detecting LN involvement using pathological specimen as reference; concordance was expressed according to Cohen's kappa coefficient. Location-based sub-analyses were performed, distinguishing among external iliac, intern iliac, obturator, common iliac, presacral and paraaortic LNs.

RESULTS

Among 870 cN0 patients, 68.9% were confirmed pN0 at pathological report; while among 234 cN+ patients, 50.5% were found with LN metastases at pathological specimen. Overall, conventional imaging showed slight concordance (64.9%) between cN and pN stages (sensitivity: 30%; specificity: 84%). At sub-analysis, no agreement between cN and pN status was found in each LN location, with the only exception of common iliac LNs with slight concordance (37.5%). Common iliac LNs achieved the highest sensitivity and positive likelihood ratio (15% and 2.4, respectively) compared to other LN locations.

CONCLUSIONS

Overall, preoperative cross-sectional imaging exhibited a slight concordance between cN and pN status. Our location-based sub-analyses showed unsatisfactory results in each LN location- Thus, nomograms combining morphological patterns with serological and clinicopathological features are urgently required.

Management of Localized Muscle-Invasive Bladder Cancer from a Multidisciplinary Perspective: Current Position of the Spanish Oncology Genitourinary (SOGUG) Working Group

This review presents challenges and recommendations on different aspects related to the management of patients with localized muscle-invasive bladder cancer (MIBC), which were discussed by a group of experts of a Spanish Oncology Genitourinary (SOGUG) Working Group within the framework of the Genitourinary Alliance project (12GU). It is necessary to clearly define which patients are candidates for radical cystectomy and which are candidates for undergoing bladder-sparing procedures. In older patients, it is necessary to include a geriatric assessment and evaluation of comorbidities. The pathological report should include a classification of the histopathological variant of MIBC, particularly the identification of subtypes with prognostic, molecular and therapeutic implications. Improvement of clinical staging, better definition of prognostic groups based on molecular subtypes, and identification of biomarkers potentially associated with maximum benefit from neoadjuvant chemotherapy are areas for further research. A current challenge in the management of MIBC is improving the selection of patients likely to be candidates for immunotherapy with checkpoint inhibitors in the neoadjuvant setting. Optimization of FDG-PET/CT reliability in staging of MIBC and the selection of patients is necessary, as well as the design of prospective studies aimed to compare the value of different imaging techniques in parallel.

The Role of Molecular Imaging in a Muscle-Invasive Bladder Cancer Patient: A Narrative Review in the Era of Multimodality Treatment

Diagnostic imaging in bladder cancer plays an important role since it is needed from pretreatment staging to follow-up, but a morphological evaluation performed with both CT and MRI showed low sensitivities and specificities in detecting pathologic lymph nodes, due to the occurrence of false positive results. Implementation of functional information provided by PET/CT could be a determinant in the management of patients with muscle-invasive bladder cancer. A focus on the role of ¹⁸F-FDG PET/CT and alternative tracers in patients with muscle-invasive bladder cancer is provided in this analysis in order to outline its potential applications in staging settings and response evaluation after neoadjuvant chemotherapy.

The Usefulness of Lymphadenectomy in Bladder Cancer-Current Status

The purpose of this review is to present the current status of lymph node dissection (LND) during radical cystectomy in patients with bladder cancer (BCa). Despite the growing body of evidence of LND utility at the time of radical cystectomy (RC) in high-risk nonmuscle-invasive and muscle-invasive BCa (MIBC), therapeutic and prognostic value and optimal extent of LND remain unsolved issues. Recently published results of the first prospective, a randomized trial assessing the therapeutic benefit of extended versus limited LND during RC, failed to demonstrate survival improvement with the extended template. Although LND is the most accurate staging procedure, the direct therapeutic effect is still not evident from the current literature, limiting the possibility of establishing clear recommendations. This indicates the need for robust and adequately powered clinical trials.

Role of PET/CT in muscle-invasive bladder cancer

The purpose of this study covered the diagnostic accuracy and usefulness of positron emission tomography/computed tomography (PET/CT) imaging in muscle invasive bladder cancer patients through previously published literature. Through 30 September, 2019, the PubMed database was searched for eligible articles that evaluated PET/CT imaging in bladder cancer patients. In general, FDG PET/CT, the most commonly used PET/CT imaging, does not show good performance for the detection of primary lesions; however, according to the literature it could accurately assess pelvic lymph node (LN) status better than other imaging technologies and it was especially helpful in determining extra-pelvic recurrences. More recently, non-FDG PET/CT imaging, such as C-11 acetate and C-11 choline, has been introduced. Although further research is required, preliminary results show the potential of these techniques to overcome the drawbacks of FDG. This concise study will overview the role of PET/CT when treating muscle-invasive bladder cancer (MIBC).

Utility of lymphadenectomy in bladder cancer: where do we stand?

PURPOSE OF REVIEW

The aim of this review is to provide insight into the current state of lymph node dissection (LND) during radical cystectomy in patients with bladder cancer (BCa).

RECENT FINDINGS

The first prospective, multicenter, randomized, phase III trial to assess the therapeutic benefit of extended versus limited LND at the time of radical cystectomy failed to demonstrate relevant improvement with extended LND, but showed that this approach does not increase overall complications. Although contemporary rate of LND during radical cystectomy has increased, it remains suboptimal. Minimally invasive radical cystectomy with LND is feasible in most patients and has similar lymph node yields and complication rates compared with open procedures when performed by experienced surgeons. Overall major complication, readmission and mortality rates do not significantly differ according to extent of LND.

SUMMARY

Meticulous LND provides both diagnostic and potentially therapeutic benefits in patients with bladder cancer. Results of ongoing trials will provide additional insights regarding the anatomic extent and therapeutic benefit of extended versus standard true pelvic-only LND.

How reliable are imaging techniques in aging males with bladder cancer?

INTRODUCTION

The aim of this study was to evaluate consistency between clinical lymph node positivity and pathological lymph node positivity in patients undergoing open radical cystectomy and pelvic lymph node dissection due to bladder cancer.

MATERIAL AND METHOD

A total of 135 patients who had open radical cystectomy, extended lymph node dissection, and clear preoperative contrast-enhanced abdominopelvic computed tomography (CT) or magnetic resonance imaging (MRI) images were included in the study. Positive clinical lymph nodes and positive pathological lymph nodeswere recorded. The largest positive clinical and pathological lymph nodeswere recorded. In terms of clinical lymph node involvement, compatibility between radiological findings and pathological results was evaluated.

RESULTS

In the CT group, the sensitivity was 25.81%, specificity was 95.45%, positive predictive value (PPV) was 66.67%, negative predictive value (NPV) was 78.50%, and accuracy was 77.31%. In the MRI group, the sensitivity was 50.00%, specificity was 100%, PPV was 100%, NPV was 76.92%, and accuracy was 81.25%. For consistency between pathological lymph nodes and clinical lymph nodes according to the imaging type, there was no statistically significant difference in the sensitivity, specificity, NPV, and accuracy rates between the imaging techniques (p > 0.05). However, the PPV was significantly higher in the MRI group than the CT group (100% vs.66.67%, respectively; p = 0.014).

CONCLUSION

Positive lymph nodes play a critical role in the prognosis of patients with bladder cancer and the sensitivity of contrast-enhanced abdominopelvic CT and MRI used routinely in clinical practice is low in lymph node detection. MRI seems more reliable than CT in lymph node detection.

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.

Evaluation of lymph node status in patients with urothelial carcinoma-still in search of the perfect imaging modality: a systematic review

While accurate lymph node status evaluation in urothelial carcinoma patients is essential for the correct disease staging and, hence, establishing the most beneficial treatment strategy, the diagnostic performance of routine imaging in regards to this issue is not satisfactory. For the purpose of this article, we systematically reviewed the contemporary literature on the sensitivity and specificity of particular imaging modalities which have been studied for detecting lymph node metastases in patients diagnosed with urothelial carcinoma. The evidence reviewed shows that computed tomography (CT), although recognized as the imaging modality of choice, is associated with marked limitations, resulting in its low sensitivity for lymph node involvement detection in urothelial carcinoma patients, with no study reporting a value higher than 46% using standard cut-off values. Markedly higher sensitivity rates may be achieved with magnetic resonance imaging (MRI), especially when using ultrasmall superparamagnetic iron oxide as the contrast agent, however, no uniform protocol has been systematically studied up to date. The vast majority of recent evidence concerns positron emission tomography (PET), which is being reported to improve the diagnostic performance of CT alone, as has been demonstrated in multiple articles, which investigated the accuracy of PET/CT at primary or post-treatment staging of urothelial carcinoma patients. However, there has been substantial heterogeneity in terms of methodology and results between those studies, making it premature to draw any definitive conclusions. The results of this review lead to a conclusion, that while CT, despite being not fully satisfactory, still remains the gold-standard method of imaging for staging purposes in urothelial carcinoma, other imaging modalities are under investigation, with promising results.

A pictorial review of bladder cancer nodal metastases

Lymph node involvement in bladder cancer is common and has prognostic implications. Early and accurate identification of metastatic lymph nodes is, therefore, important in ensuring appropriate patient triage and management. The purpose of this review is to provide a pictorial and educational overview of the staging and imaging appearance of metastatic lymph nodes in bladder cancer. Additionally, a secondary aim of this manuscript is to provide a review of the diagnostic accuracy of common imaging modalities available for detecting metastatic lymph nodes in affected patients.

11C-acetate PET/MRI in bladder cancer staging and treatment response evaluation to neoadjuvant chemotherapy: a prospective multicenter study (ACEBIB trial)

Background

To evaluate the accuracy of ¹¹C-acetate Positron Emission Tomography/Magnetic Resonance Imaging (PET/MRI) in bladder cancer (BC) staging and monitoring response to neoadjuvant chemotherapy (NAC).

Methods

Eighteen patients were prospectively enrolled. Fifteen treatment naive patients underwent ¹¹C-acetate PET/MRI before transurethral resection of bladder tumor (TUR-BT) for primary tumor evaluation. Five patients with muscle invasive BC were imaged after NAC and prior to radical cystectomy (RC) with extended pelvic lymph node dissection (ePLND) for NAC treatment response evaluation. Two patients were part of both cohorts. ¹¹C-acetate PET/MRI findings were correlated with histopathology. Accuracy for lymph node detection was evaluated on patient and the ePLND template (10 regions) levels.

Results

The sensitivity, specificity and accuracy of ¹¹C-acetate PET/MRI for the detection of muscle invasive BC was 1.00, 0.69 and 0.73 while the area under the receiver operating characteristic curve (95% confidence interval) was 0.85 (0.55–1.0), respectively. All five NAC patients underwent chemotherapy as planned and ¹¹C-acetate PET/MRI correctly staged three patients, overstaged one and understaged one patient compared with RC and ePLND findings. A total of 175 lymph node were removed, median of 35 (range, 27–43) per patient in five patients who had RC and ePLND while 12 (7%) harboured metastases. Sensitivity, specificity, accuracy and AUC for N-staging were 0.20, 0.96, 0.80 and 0.58 on the ePLND template (10 regions) level.

Conclusions

¹¹C-acetate PET/MRI is feasible for staging of BC although sensitivity for the detection of nodal metastases is low. Monitoring response to NAC shows promise and warrants evaluation in larger studies.

Trial registration

ClinicalTrials.gov Identifier: NCT01918592, registered August 8 2013