Current Status of Lymph Node Imaging in Bladder and Prostate Cancer

Sentinel lymph node assessment in melanoma: current state and future directions

Assessment of sentinel lymph node status is an important step in the evaluation of patients with melanoma for both prognosis and therapeutic management. Pathologists have an important role in this evaluation. The methodologies have varied over time, from the evaluation of dimensions of metastatic burden to determination of the location of the tumour deposits within the lymph node to precise cell counting. However, no single method of sentinel lymph node tumour burden measurement can currently be used as a sole independent predictor of prognosis. The management approach to sentinel lymph node-positive patients has also evolved over time, with a more conservative approach recently recognised for selected cases. This review gives an overview of past and current status in the field with a glimpse into future directions based on prior experiences and clinical trials.

The Sentinel Lymph Node in Treatment Planning: A Narrative Review of Lymph-Flow-Guided Radiotherapy

The sentinel lymph node technique is minimally invasive and used routinely by surgeons, reducing the need for morbid extensive lymph node dissections, which is a significant advantage for cancer staging and treatment decisions. The sentinel lymph node could also help radiation oncologists to identify tumor drainage for each of their patients, leading to a more personalized radiotherapy, instead of a probabilistic irradiation based on delineation atlases. The aim is both to avoid recurrence in unexpected areas and to limit the volume of irradiated healthy tissues. The aim of our study is to evaluate the impact of sentinel lymph node mapping for radiation oncologists. This concept, relying on sentinel lymph node mapping for treatment planning, is known as lymph-flow-guided radiotherapy. We present an up-to-date narrative literature review showing the potential applications of the sentinel lymph node technique for radiotherapy, as well as the limits that need to be addressed before its routine usage.

Status of 18F-PSMA-1007-PET/CT compared with multiparametric MRI in preoperative evaluation of prostate cancer

PURPOSE

Treatment of primary prostate cancer extremely depends on preoperative stage. The role of ¹⁸F-1007-PSMA-PET/CT in preoperative staging has not been well defined. Our aim was to compare the diagnostic performance of ¹⁸F-1007-PEMA-PET/CT, mpMRI, and mpMRI + PEMA-PET/CT in local progression and lymph node invasion of prostate cancer using histopathology as the gold standard.

MATERIALS AND METHODS

In this retrospective study, all patients with prostate cancer who underwent mpMRI and ¹⁸F-PSMA-1007-PET/CT before operation were included. The role of preoperative imaging was evaluated by predicting the sensitivity and specificity of EPE (extraprostatic extension), SVI (seminal vesicle invasion), and lymph node invasion results.

RESULTS

Ultimately, 130 patients were included in this study. In the preoperative judgment of EPE and SVI, mpMRI + PSMA-PET/CT had higher sensitivity and specificity. When predicting lymph node metastasis, PSMA-PET/CT was the best choice. The accuracy of mpMRI + PSMA-PET/CT and PSMA-PET/CT in the T and N stages, respectively, was affected by the least factors.

CONCLUSIONS

Based on the combined results of mpMRI and ¹⁸F-1007-PSMA-PET/CT, the accuracy of the preoperative judgment of prostatic capsule invasion can be improved, which may be conducive to developing intra-fascial technology while ensuring no tumor-touch isolation. PSMA-PET/CT has the advantages over mpMRI alone in terms of lymph node positivity. Compared with PSMA-PET/CT alone, the combined results can improve the sensitivity, but reduce specificity. Therefore, it is recommended to focus on PSMA-PET/CT to decide whether lymph node dissection should be performed.

Validating the screening criteria for bone metastases in treatment-naïve unfavorable intermediate and high-risk prostate cancer - the prevalence and location of bone- and lymph node metastases

OBJECTIVE

The European Association of Urology (EAU) recommends a bone scan for newly diagnosed unfavorable intermediate- and high-risk prostate cancer. We aimed to validate the screening criteria for bone metastases in patients with treatment-naïve prostate cancer.

METHODS

This single-center retrospective study included all patients with treatment-naïve unfavorable intermediate- or high-risk prostate cancer. All underwent MRI of the lumbar column (T2Dixon) and pelvis (3DT2w, DWI, and T2 Dixon). The presence and location of lymph node and bone metastases were registered according to risk groups and radiological (rad) T-stage. The risk of lymph node metastases was assessed by odds ratio (OR).

RESULTS

We included 390 patients, of which 68% were high-risk and 32% were unfavorable intermediate-risk. In the high-risk group, the rate of regional- and non-regional lymph node metastases was 11% and 6%, respectively, and the rate of bone metastases was 10%. In the unfavorable intermediate-risk group, the rate of regional- and non-regional lymph node metastases was 4% and 0.8%, respectively, and the rate of bone metastases was 0.8%. Metastases occurred exclusively in the lumbar column in 0.5% of all patients, in the pelvis in 4%, and the pelvis and lumbar column in 3%. All patients with bone metastases had radT3-4, and patients with radT3-4 showed a four-fold increased risk of lymph node metastases (OR 4.48, 95% CI: 2.1-9.5).

CONCLUSION

Bone metastases were found in 10% with high-risk prostate cancer and 0.8% with unfavorable intermediate-risk. Therefore, we question the recommendation to screen the unfavorable intermediate-risk group for bone metastases.

KEY POINTS

• The rate of bone metastases was 10% in high-risk patients and 0.8% in the unfavorable intermediate-risk group. • The rate of lymph-node metastases was 17% in high-risk patients and 5% in the unfavorable intermediate-risk group. • No bone metastases were seen in radiologically localized disease.

Utility of Lymphadenectomy in Prostate Cancer: Where Do We Stand?

The purpose of this review is to summarize the current knowledge on lymph node dissection (LND) in prostate cancer (PCa) patients undergoing radical prostatectomy (RP). Despite a growing body of evidence, the utility and therapeutic and prognostic value of such an approach, as well as the optimal extent of LND, remain unsolved issues. Although LND is the most accurate staging procedure, the direct therapeutic effect is still not evident from the current literature, which limits the possibility of establishing clear recommendations. This indicates the need for further robust and adequately designed high-quality clinical trials.

[Modern tomography imaging techniques in urological diseases]

BACKGROUND

Radiologic imaging is important for the detection, staging and follow-up of urological tumors. Basic therapy decisions for both oncological (surgical vs. systemic therapy, e.g. in testicular cancer) and non-oncological pathologies (interventional vs. conservative therapy, e.g. for ureteral stones) depend largely on the tomographic imaging performed. Due to its almost ubiquitous availability, speed and cost-effectiveness, computed tomography (CT) plays an important role not only in the clarification of abdominal trauma and non-traumatic emergencies, but also in staging and follow-up of oncological patients. However, the level of radiation exposure, impaired renal function and allergies to iodinated contrast media limit the use of CT. Magnetic resonance imaging (MRI) can be a good alternative for many areas of application in oncological and non-oncological imaging due to its high soft tissue differentiation and functional-specific protocols but without the use of ionizing radiation.

AIM

In the following, the main indications of abdominal and pelvic CT and MRI in urology and their limitations are summarized.

RESULTS

The areas of application between CT and MRI are increasingly overlapping, since the latest developments in CT continue to further reduce radiation exposure and increase contrast information, while the speed and robustness of MRI are significantly improving at the same time.

Rational Linker Design to Accelerate Excretion and Reduce Background Uptake of Peptidomimetic PSMA-Targeting Hybrid Molecules

The evolution of peptidomimetic hybrid molecules for preoperative imaging and guided surgery targeting the prostate-specific membrane antigen (PSMA) significantly progressed over the past few years, and some approaches are currently being evaluated for further clinical translation. However, accumulation in nonmalignant tissue such as kidney, bladder, spleen, or liver might limit tumor-to-background contrast for precise lesion delineation, particularly in a surgical setting. To overcome these limitations, a rational linker design aims at the development of a second generation of PSMA-11-based hybrid molecules with an enhanced pharmacokinetic profile and improved imaging contrast. Methods: A selection of rationally designed linkers was introduced to the PSMA-targeting hybrid molecule Glu-urea-Lys-HBED-CC-IRDye800CW, resulting in a second-generation peptidomimetic hybrid molecule library. The biologic properties were investigated in cell-based assays. In a preclinical proof-of-concept study with the radionuclide 68Ga, the impact of the modifications was evaluated by determination of specific tumor uptake, pharmacokinetics, and fluorescence imaging in tumor-bearing mice. Results: The modified hybrid molecules carrying various selected linkers revealed high PSMA-specific binding affinity and effective internalization. The highest tumor-to-background contrast of all modifications investigated was identified for the introduction of a histidine- (H) and glutamic acid (E)-containing linker ((HE)3-linker) between the PSMA-binding motif and the chelator. In comparison to the parental core structure, uptake in nonmalignant tissue was significantly reduced to a minimum, as exemplified by an 11-fold reduced spleen uptake from 38.12 ± 14.62 percentage injected dose (%ID)/g to 3.47 ± 1.39 %ID/g (1 h after injection). The specific tumor uptake of this compound (7.59 ± 0.95 %ID/g, 1 h after injection) was detected to be significantly higher than that of the parental tracer PSMA-11. These findings confirmed by PET and fluorescence imaging are accompanied by an enhanced pharmacokinetic profile with accelerated background clearance at early time points after injection. Conclusion: The novel generation of PSMA-targeting hybrid molecules reveals fast elimination, reduced background organ enrichment, and high PSMA-specific tumor uptake meeting the key demands for potent tracers in nuclear medicine and fluorescence-guided surgery. The approach's efficacy in improving the pharmacokinetic profile highlights the strengths of rational linker design as a powerful tool in strategic hybrid-molecule development.

A longitudinal study evaluating interim assessment of neoadjuvant chemotherapy for bladder cancer

OBJECTIVES

To evaluate the usefulness of radiological re-staging after two and four cycles of neoadjuvant chemotherapy (NAC), the impact of re-staging on further patient management, and the correlation between clinical and final pathological tumour stage at radical cystectomy (RC).

PATIENTS AND METHODS

We conducted a longitudinal, single-centre, cohort study of prospectively collected consecutive patients who underwent NAC and RC for urothelial muscle-invasive bladder cancer between July 2001 and December 2017. Patients underwent repeated computed tomography scans for re-staging after two cycles of NAC and after completion of NAC before RC.

RESULTS

Of 180 patients, 110 had ≥four cycles of NAC and had complete imaging available. In the entire cohort, further patient management was only changed in 2/180 patients (1.1%) after two cycles of NAC based on radiological findings. Patients who were stable after two cycles but then downstaged after at least four cycles of NAC had a similarly lowered risk of death (hazard ratio [HR] 0.53). Only one patient downstaged after two cycles was subsequently upstaged after four cycles. Clinical downstaging was observed in 51 patients (46%), 55 patients (50%) had no change in clinical stage and four patients (3.6%) were clinically upstaged. Patients clinically downstaged after four cycles of NAC had a lower risk of death (HR 0.49, 95% confidence interval 0.25-0.94; P = 0.033) compared to those with no change or upstaged after completion of NAC.

CONCLUSIONS

Re-staging of muscle-invasive bladder cancer after two cycles of NAC offers little additional information, rarely changes patient management, and may therefore be omitted, whereas re-staging after completion of NAC by CT is a strong predictor of overall survival.

The role of pre-biopsy mpMRI in lymph node staging for prostate cancer

INTRODUCTION

Prostate cancer (PCa) staging is an integral part in the management of prostate cancer. The gold standard for diagnosing lymph node invasion is a surgical lymphadenectomy, with no superior imaging modality available at the clinician's disposal. Our aim in this study is to identify if a pre-biopsy multiparametric MRI (mpMRI) can provide enough information about pelvic lymph nodes in intermediate and high risk PCa patients, and whether it can substitute further cross sectional imaging (CSI) modalities of the abdomen and pelvis in these risk categories.

METHODS

Patients with intermediate and high risk prostate cancer were collected between January 2015 and June 2019, while excluding patients who did not undergo a pre-biopsy mpMRI or a CSI. Date regarding biopsy result, PSA, MRI results, CSI imaging results were collected. Using Statistical Package for the Social Sciences (SPSS) version 24.0, statistical analysis was conducted using the Cohen's Kappa agreement for comparison of mpMRI with CSI. McNemar's test and receiver operator curve (ROC) curve were used for comparison of sensitivity of both tests when comparing to the gold standard of lymphadenectomy.

RESULTS

A total of 143 patients fit the inclusion criteria. We further stratified our patients into according to PSA level and Gleason score. Overall, agreement between mpMRI and all CSI was 0.857. When stratifying patients based on Gleason score and PSA, the higher the grade or PSA, the higher agreement between mpMRI and CSI. The sensitivity of mpMRI (73.7%) is similar to CSI (68.4%). When comparing CSI sensitivity to that of mpMRI, no significant difference was present by utilizing the McNemar test and very similar receiver operating characteristic curve.

CONCLUSION

A pre-biopsy mpMRI can potentially substitute further cross sectional imaging in our cohort of patients. However, larger prospective studies are needed to confirm our findings.

Management of Prostate Cancer with Systemic Therapy: A Prostate Cancer Unit Perspective

The scenario of systemic therapy for prostate cancer is rapidly evolving, with new drugs and new treatment options. To update the background knowledge of shared uro-oncologic practice, we reviewed current statements and landmarks in systemic therapy. A number of new agents are under investigation in non-metastatic and metastatic disease. Similarly, new target imaging technologies are under development to improve the detection rate of true non-metastatic and true metastatic patient. Five new drugs have shown to be effective on progression-free and overall survival in metastatìc prostate cancer. However, the optimal sequencing of these treatments requires further investigation. The tolerability and side effects of the new drugs are also crucial issues to be discussed, as well as their activity against the disease. The uro-oncologic team has to stay updated about new medical therapies in order to be confident in debating with other professionals involved in prostate cancer decision making. Different points of view and nuances should be shared during multidisciplinary group discussions to achieve a balanced decision in disease management.

Lymphatic metastasis of bladder cancer: Molecular mechanisms, diagnosis and targeted therapy

Bladder cancer is the most common and lethal cancer of the urinary system. Lymphatic metastasis is the primary and main metastatic type of bladder cancer, leading to an extremely poor prognosis in patients. Therefore, a better understanding of molecular mechanisms may provide potential targets for the diagnosis and treatment of lymphatic metastasis in bladder cancer. Herein, we summarize the current knowledge of molecular mechanisms of the lymphatic metastasis in bladder cancer, including lymphangiogenesis and its regulators, noncoding RNAs, and microenvironment-associated molecules. Novel radiomics and genomics approaches have substantially improved the preoperative diagnostic accuracy of lymph node metastasis in patients with bladder cancer. Newly discovered targets may lead to promising therapeutic strategies for clinical intervention in lymphatic metastasis of bladder cancer. More basic and translational studies need to be conducted to further clarify the molecular mechanisms, and identify predictive markers and therapeutic targets of lymphatic metastasis for bladder cancer patients.

Management of Clinically Regional Node-Positive Urothelial Carcinoma of the Bladder

PURPOSE OF REVIEW

Clinically regional node-positive (cN+) urothelial carcinoma of the bladder requires a multi-modal management approach amidst growing recognition that it represents a spectrum of disease. Herein, we review the contemporary evidence for the natural history, evaluation, and management of clinically regional node-positive urothelial carcinoma of the bladder, highlighting recent changes in lymph node staging.

RECENT FINDINGS

Despite advances in techniques, cross-sectional imaging remains relatively insensitive for the detection of lymph node metastases. Recent changes to nodal staging that distinguish between cN1, cN2-3, and non-regional lymph node metastases reflect an increasing understanding that node-positive disease is heterogeneous and its management must be individualized according to nodal staging. Systemic therapy remains the initial management strategy, either alone or in conjunction with radiotherapy, with choice and sequencing of agents extrapolated from studies of metastatic disease. Consolidative radical cystectomy is an option for patients with disease response to upfront systemic therapy, and several series demonstrate a subset of patients with favorable oncologic outcomes. The comparative effectiveness of radiotherapy and radical cystectomy as local therapy remains an important evidence gap. Future studies that identify predictive biomarkers will help inform optimal choice of systemic therapy. The management of clinically regional node-positive disease requires a multimodal approach comprising both systemic and local therapy, tailored to the patient and to disease response. While choice of systemic therapy will be informed by ongoing studies in patients with metastatic disease, including the elucidation of predictive biomarkers, the comparative effectiveness of local therapies remains an important evidence gap.

Nuclear Imaging for Bone Metastases in Prostate Cancer: The Emergence of Modern Techniques Using Novel Radiotracers

Accurate staging of prostate cancer (PCa) at initial diagnosis and at biochemical recurrence is important to determine prognosis and the optimal treatment strategy. To date, treatment of metastatic PCa has mostly been based on the results of conventional imaging with abdominopelvic computed tomography (CT) and bone scintigraphy. However, these investigations have limited sensitivity and specificity which impairs their ability to accurately identify and quantify the true extent of active disease. Modern imaging modalities, such as those based on the detection of radioactively labeled tracers with combined positron emission tomography/computed tomography (PET/CT) scanning have been developed specifically for the detection of PCa. Novel radiotracers include ¹⁸F-sodium fluoride (NaF), ¹¹C-/¹⁸F-fluorocholine (FCH), ¹⁸F-fluordihydrotestosterone (FDHT), ⁶⁸Gallium and ¹⁸F-radiolabeled prostate-specific membrane antigen (e.g., ⁶⁸Ga-PSMA-11, ¹⁸F-DCFPyL). PET/CT with these tracers outperforms conventional imaging. As a result of this, although their impact on outcome needs to be better defined in appropriate clinical trials, techniques like prostate-specific membrane antigen (PSMA) PET/CT have been rapidly adopted into clinical practice for (re)staging PCa. This review focuses on nuclear imaging for PCa bone metastases, summarizing the literature on conventional imaging (focusing on CT and bone scintigraphy—magnetic resonance imaging is not addressed in this review), highlighting the prognostic importance of high and low volume metastatic disease which serves as a driver for the development of better imaging techniques, and finally discussing modern nuclear imaging with novel radiotracers.

Whole-body magnetic resonance imaging for prostate cancer assessment: Current status and future directions

Over the past decade, updated definitions for the different stages of prostate cancer and risk for distant disease, along with the advent of new therapies, have remarkably changed the management of patients. The two expectations from imaging are accurate staging and appropriate assessment of disease response to therapies. Modern, next-generation imaging (NGI) modalities, including whole-body magnetic resonance imaging (WB-MRI) and nuclear medicine (most often prostate-specific membrane antigen [PSMA] positron emission tomography [PET]/computed tomography [CT]) bring added value to these imaging tasks. WB-MRI has proven its superiority over bone scintigraphy (BS) and CT for the detection of distant metastasis, also providing reliable evaluations of disease response to treatment. Comparison of the effectiveness of WB-MRI and molecular nuclear imaging techniques with regard to indications and the definition of their respective/complementary roles in clinical practice is ongoing. This paper illustrates the evolution of WB-MRI imaging protocols, defines the current state-of-the art, and highlights the latest developments and future challenges. The paper presents and discusses WB-MRI indications in the care pathway of men with prostate cancer in specific key situations: response assessment of metastatic disease, "all in one" cancer staging, and oligometastatic disease.

Development and Validation of a Nomogram to Predict Lymph Node Metastasis in Patients With T1 High-Grade Urothelial Carcinoma of the Bladder

Purpose

This study aims to develop and validate a nomogram to predict lymph node (LN) metastasis preoperatively in patients with T1 high-grade urothelial carcinoma.

Methods

We retrospectively evaluated the data of 2,689 patients with urothelial carcinoma of the bladder (UCB) treated with radical cystectomy (RC) and bilateral lymphadenectomy in two medical centers. Eventually, 412 patients with T1 high-grade urothelial carcinoma were enrolled in the primary cohort to develop a prognostic nomogram designed to predict LN status. An independent validation cohort (containing 783 consecutive patients during the same period) was subjected to validate the predicting model. Binary regression analysis was used to develop the predicting nomogram. We assessed the performance of the nomogram concerning its clinical usefulness, calibration, and discrimination.

Results

Overall, 69 (16.75%), and 135 (17.24%) patients had LN metastasis in the primary cohort and external validation cohort, respectively. The final nomogram included information on tumor number, tumor size, lymphovascular invasion (LVI), fibrinogen, and monocyte-to-lymphocyte ratio (MLR). The nomogram showed good predictive accuracy and calibration with a concordance index in the primary cohort of 0.853. The application of the nomogram in the external validation cohort still gave good discrimination (C-index, 0.845) and good calibration. The analysis of the decision curve shows that the nomogram has clinical application value.

Conclusion

The nomogram that incorporated the tumor number, tumor size, LVI, fibrinogen, and MLR showed favorable predictive accuracy for LN metastasis. It may be conveniently used to predict LN metastasis in patients with T1 high-grade urothelial carcinoma and be helpful in guiding treatment decisions.

Routine Preoperative Bone Scintigraphy Has Limited Impact on the Management of Patients with Invasive Bladder Cancer

BACKGROUND

According to current guidelines, bone scintigraphy is not routinely indicated in patients with invasive bladder cancer prior to radical cystectomy unless specific symptoms are present. These guidelines, however, are based on sparse data of low quality.

OBJECTIVE

To assess the clinical impact of routine staging bone scintigraphy on further patient management.

DESIGN, SETTING, AND PARTICIPANTS

A retrospective, single-center study of 1287 consecutive patients, who were scheduled to undergo radical cystectomy due to invasive bladder cancer between January 2000 and December 2017, was conducted. All patients were prospectively followed up according to our institutional protocol.

INTERVENTION

Bone scintigraphy as staging imaging prior to radical cystectomy.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

The primary endpoint was the change in intended patient management. Secondary endpoints were the need for additional imaging, the diagnostic performance of baseline bone scintigraphy, and the association between clinical and radiological findings on bone metastases and survival. Logistic and Cox regression models were used for univariate and multivariate analyses.

RESULTS AND LIMITATIONS

Of 1287 patients scheduled for radical cystectomy, 1148 (89%) underwent bone scintigraphy as staging imaging. Overall, baseline bone scintigraphy led to a change in the intended management in 19/1148 (1.7%) patients. Additional imaging was performed in 44/1148 (4%) patients. Although positive bone scintigraphy findings were associated with the occurrence/development of bone metastases, the diagnostic performance of baseline bone scintigraphy was generally poor (positive predictive value, negative predictive value, sensitivity, and specificity were 56%, 89%, 27%, and 96%, respectively). Higher clinical tumor stage and the nonperformance of cystectomy had negative impacts on cancer-specific survival and overall survival, while positive bone scintigraphy was associated with worse cancer-specific survival. This study was limited by its retrospective nature and the lack of follow-up bone scintigraphy in all patients.

CONCLUSIONS

These results demonstrate the limited value of bone scintigraphy in the staging of invasive bladder cancer and do not support its routine use.

PATIENT SUMMARY

In this study, we looked at the clinical impact of bone scintigraphy on the diagnostics of patients with invasive bladder cancer. We found that routine staging bone scintigraphy had limited impact on further patient management. We conclude that bone scintigraphy should not be part of routine staging in patients with invasive bladder cancer.

Limitations of abdominopelvic CT and multiparametric MR imaging for detection of lymph node metastases prior to radical prostatectomy

PURPOSE

To investigate the performance of pre-surgery CT and multiparametric MRI (mpMRI) to identify lymph node (LN) metastases in the Michigan Urological Surgery Improvement Collaborative (MUSIC). Abdominopelvic CT and mpMRI are commonly used for intermediate- and high-risk prostate cancer (PCa) staging.

METHODS

Retrospective analysis of the MUSIC registry identified patients undergoing robot-assisted radical prostatectomy (RP) between 3/2012 and 7/2018. Patients were classified according to pre-surgery imaging modality. Primary outcomes were operating characteristics of CT and mpMRI for detection of pathologic LN involvement (pN1).

RESULTS

A total of 10,250 patients underwent RP and 3924 patients (38.3%) underwent CT and/or mpMRI prior to surgery. Suspicion for LN involvement was identified on 2.3% CT and 1.9% mpMRI. Overall, 391 patients were pN1(3.8%), including 0.1% low-, 2.1% intermediate-, and 10.9% high-risk PCa patients. Of 235 pN1 patients that underwent CT prior, far more had negative (91.1%) than positive (8.9%) findings, yielding sensitivity: 8.9%, specificity: 98.3%, negative predictive value (NPV): 92.1%, and positive predictive value (PPV): 32.3% for CT with regard to LN metastases. Similarly, more patients with pN1 disease had negative mpMRI (81.0%) then suspicious or indeterminate MRI (19.0%), yielding sensitivity: 19.0%, specificity: 97.3%, NPV: 95.9%, and PPV: 26.7%.

CONCLUSIONS

Abdominopelvic CT and mpMRI have clear limitations in identifying LN metastases. Additional clinicopathologic features should be considered when making management decisions, as 2.1% and 10.9% with intermediate-and high-risk cancer had metastatic LNs. The majority of pN1 patients had a negative CT or a negative/indeterminate mpMRI prior to RP. Pelvic LN dissection should be performed in RP patients with intermediate- or high-risk PCa, independent of preoperative imaging results.

The Role of Radical Prostatectomy and Lymph Node Dissection in Clinically Node Positive Patients

Patients diagnosed with clinically node-positive prostate cancer represent a population that has historically been thought to harbor systemic disease. Increasing evidence supports the role of local therapies in advanced disease, but few studies have focused on this particular population. In this review we discuss the limited role for conventional cross sectional imaging for accurate nodal staging and how molecular imaging, although early results are promising, is still far from widespread clinical utilization. To date, evidence regarding the role of radical prostatectomy and pelvic lymph node dissection in clinically node-positive disease comes from retrospective studies; overall surgery appears to be a reasonable option in selected patients, with improved oncological outcomes that could be attributed to both to its potential curative role in disease localized to the pelvis and to the improved staging to help guide subsequent multimodal treatment. The role of surgery in clinically node-positive disease needs higher-level evidence but meanwhile, radical prostatectomy with extended pelvic lymph-node dissection can be offered as a part of a multimodality approach with the patient.

The Basics of Sentinel Lymph Node Biopsy: Anatomical and Pathophysiological Considerations and Clinical Aspects

Sentinel lymph node (SLN) is the first node to receive the drainage directly from a tumor. Detection and pathological examination of the SLN is an important oncological procedure that minimizes morbidity related to extensive nodal dissection. SLN biopsy was first reported in 1960 but took approximately 40 years to come into general practice following reports of good outcomes in patients with melanoma. After many years of observation and research on its use in various malignancies SLN biopsy has become the standard surgical treatment in patients with malignant melanoma, breast, vulvar, and cervical cancers. Along with the introduction of new technologies, such as the fluorescent dyes indocyanine green (ICG) and near-infrared fluorescence (NIR), and pathologic ultrastaging, SLN detection rate has increased and false-negative rate has decreased. This literature review aimed to present an overview of the basic concepts and clinical aspects of SLN biopsy in the light of the current research.

Optical and Cross-Sectional Imaging Technologies for Bladder Cancer

Optical and cross-sectional imaging plays critical roles in bladder cancer diagnostics. White light cystoscopy remains the cornerstone for the management of non-muscle-invasive bladder cancer. In the last decade, significant technological improvements have been introduced for optical imaging to address the known shortcomings of white light cystoscopy. Enhanced cystoscopy modalities such as blue light cystoscopy and narrowband imaging survey a large area of the urothelium and provide contrast enhancement to detect additional lesions and decrease cancer recurrence. However, higher false-positive rates accompany the gain of sensitivity. Optical biopsy technologies, including confocal laser endomicroscopy and optical coherence tomography, provide cellular resolutions combined with subsurface imaging, thereby enabling optical-based cancer characterization, and may lead to real-time cancer grading and staging. Coupling of fluorescently labeled binding agents with optical imaging devices may translate into high molecular specificity, thus enabling visualization and characterization of biological processes at the molecular level. For cross-sectional imaging, upper urinary tract evaluation and assessment potential extravesical tumor extension and metastases are currently the primary roles, particularly for management of muscle-invasive bladder cancer. Multi-parametric MRI, including dynamic gadolinium-enhanced and diffusion-weighted sequences, has been investigated for primary bladder tumor detection. Ultrasmall superparamagnetic particles of iron oxide (USPIO) are a new class of contrast agents that increased the accuracy of lymph node imaging. Combination of multi-parametric MRI with positron emission tomography is on the horizon to improve accuracy rates for primary tumor diagnostics as well as lymph node evaluation. As these high-resolution optical and cross-sectional technologies emerge and develop, judicious assessment and validation await for their clinical integration toward improving the overall management of bladder cancer.

Outcome of sentinel lymph node biopsy in patients with clinically non-metastatic renal cell carcinoma

OBJECTIVE

To investigate the rate of occult SN metastases, oncological outcome, and association of recurrence with the pattern of lymphatic tumour drainage in RCC.

MATERIALS AND METHODS

A pooled RCC sub-group analysis was conducted of secondary endpoints from a published feasibility and a phase II prospective single-arm SN study to investigate oncological outcome. Patients with cT1-3 (<10 cm) cN0M0 RCC of any sub-type were enrolled. After intratumoural injection of Tc^99m nanocolloid, pre-operative imaging of SNs with SPECT/CT was followed by (partial) nephrectomy with SN and regional lymph node dissection using a γ-probe. The patients were followed with a risk-adapted surveillance programme. Endpoints of the studies were analysed using Cox proportional hazard models.

RESULTS

Sixty-six RCC patients were included. Two patients (3%, 95% CI =0.5-11%) had occult SN metastases and remained free of disease at 57 and 72 months. Ten patients (15%, 95% CI =7-26%) developed recurrences, and four (6%, 95% CI =2.3-14.5%) had died of disease at a median follow-up of 57 months (IQR =18-72 months). Occurrence of distant metachronous metastases were associated with tumour size (HR =1.39, p = 0.02), pT stage (HR =6.83, p < 0.01 for comparison T1 vs T3/4), Grade 3/4 (HR =8.38, p = 0.05 for comparison 1/2 vs 3/4) and interaortocaval sentinel lymph node location (HR =10.52, p = 0.03 for comparison yes vs no).

CONCLUSIONS

The rate of occult metastatic SN is low, but long disease-free survival (DFS) was observed in two patients with occult SN metastases. We hypothesize an interaortocaval lymphatic route in thoracic recurrences. Evaluation of the prognostic and therapeutic role of sentinel lymph node biopsy (SLNB) requires a clinical trial in high-risk RCC.

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.

Beyond penile cancer, is there a role for sentinel node biopsy in urological malignancies?

This review aims to discuss the current state-of-the-art of sentinel node (SN) mapping in urological malignancies. The principles and methodological aspects of lymphatic mapping and SN biopsy in urological malignancies are reviewed. Literature search was restricted to English language. The references of the retrieved articles were examined to identify additional articles. The review also includes meta-analyses published in the past 5 years. SN biopsy for penile cancer is recommended by the European Association of Urology as the preferred staging tool for clinically node-negative patients with at least T1G2 tumours (level of evidence 2a, Grade B). The feasibility of SN biopsy in prostate cancer has been repeatedly demonstrated and its potential value is increasingly being recognised. However, conclusive prospective clinical data as well as consensus on methodology and patient selection are still lacking. For bladder, renal and testicular cancer, only few studies have been published, and concerns around high false-negative rates remain. Throughout the years, the uro-oncological field has portrayed a pivotal role in the development of the SN concept. Recent advances such as hybrid tracers and novel intraoperative detection tools such as fluorescence and portable gamma imaging will hopefully encourage prospectively designed clinical trials which can further substantiate the potential of the SN approach in becoming an integral part of staging in urological malignancies beyond penile cancer.