Anatomical localization of radiocolloid tracer deposition affects outcome of sentinel node procedures in prostate cancer

Robotic-assisted surgery for the treatment of urologic cancers: recent advances

INTRODUCTION

Recent advancements in single-port surgery, robotic platforms, 3D models and artificial intelligence have transformed surgical procedures, especially in urology. These innovations enhance precision, safety, and efficacy, reducing invasiveness and recovery times. The review focuses on the latest in robotic-assisted surgery for genitourinary cancers, highlighting the shift toward personalized, minimally invasive treatments.

AREAS COVERED

A bibliographic search across PubMed, Scopus, and EMBASE databases focused on the last four years of innovations in robotic surgery for urologic tumors. The review highlights the use of the Da Vinci Single Port robotic system, available robotic platforms worldwide, advancements in 3D virtual models, artificial intelligence in robotic surgery and the application of molecular imaging for assessing primary lymph nodes and treating lymph node metastases and local recurrences in prostate cancer.

EXPERT OPINION

The integration of single-port surgery, new robotic platforms, 3D models and artificial intelligence in urological oncology promises transformative impacts on diagnosis, treatment and cost-effectiveness. Despite benefits like enhanced precision and expanded surgical access, challenges such as high costs, training needs, and technological integration barriers persist. Collaboration and further research are critical to optimize outcomes, improve safety protocols, and ensure equitable global access to these innovations.

Progress of fluorescence imaging in lymph node dissection surgery for prostate and bladder cancer

Fluorescence imaging is a relatively new imaging method used to visualize different tissue structures to help guide intraoperative operations, which has potential advantages with high sensitivity and contrast compared to conventional imaging. In this work, we review fluorescent contrast agents and devices used for lymphatic system imaging. Indocyanine green is the most widely utilized due to its high sensitivity, specificity, low background fluorescence, and safety profile. In prostate and bladder cancer lymph node dissection, the complex lymphatic drainage can result in missed metastatic nodes and extensive dissection increases the risk of complications like lymphocele, presenting a significant challenge for urologists. Fluorescence-guided sentinel lymph node dissection facilitates precise tumor staging. The combination of fluorescence and radiographic imaging improves the accuracy of lymph node staging. Multimodal imaging presents new potential for precisely identifying metastatic pelvic lymph nodes.

Can contralateral lymph-node metastases be ruled out in prostate cancer patients with only unilaterally positive prostate biopsy?

PURPOSE

Our study evaluated the diagnostic benefits of bilateral pelvic lymphadenectomy in prostate cancer patients with unilaterally positive prostate biopsy.

METHODS

Our retrospective analysis included clinical, surgical, and histopathological data of 440 prostate cancer patients treated with radical prostatectomy and bilateral sentinel-guided and risk-adapted complementary extended pelvic lymphadenectomy at our hospital between 2015 and 2022. We performed multiparametric logistic regression analysis to identify the most relevant predictive factors for detecting lymph-node metastasis in this group of patients.

RESULTS

Overall, 373 patients (85%) had histopathologically bilateral tumours and 45 (10%) pN1 status, of which 22 (49%) also had lymph-node metastasis contralateral to the side of the positive prostate biopsy. In two patients with confirmed unilateral disease in prostatectomy specimens, bilateral lymph-node metastases were observed. Eight pN1 patients would have been missed by unilateral pelvic lymphadenectomy, resulting in a false-negative rate of 18%, 82% sensitivity, and 98% accuracy. Clinical tumour category, International Society of Urological Pathology grade, and percentage of prostate biopsy cores that are positive, as well as number of dissected lymph nodes contralateral to positive prostate biopsy, were determined as the most relevant predictive factors for detecting lymph-node metastasis. Our analysis was limited by its retrospective nature as well as by the fact that 80% of the patients did not receive MRI-targeted biopsy.

CONCLUSION

Our study highlights the diagnostic value of bilateral pelvic lymphadenectomy and the need for careful planning in surgery for prostate cancer patients with unilaterally positive prostate biopsy.

A Fluorescent and Magnetic Hybrid Tracer for Improved Sentinel Lymphadenectomy in Prostate Cancer Patients

In prostate cancer, sentinel lymph node dissection (sLND) offers a personalized procedure with staging ability which is at least equivalent to extended LND while inducing lower morbidity. A bimodal fluorescent-radioactive approach was introduced to improve sentinel LN (SLN) detection. We present the first in-human case series on exploring the use of a fluorescent-magnetic hybrid tracer in a radiation-free sLND procedure. Superparamagnetic iron oxide nanoparticles and indocyanine green were administered simultaneously in five prostate cancer patients scheduled for extended LND, sLND and radical prostatectomy. In situ and ex vivo fluorescence and magnetic signals were documented for each LN sample detected via a laparoscopic fluorescence imaging and magnetometer system. Fluorescence and magnetic activity could be detected in all patients. Overall, 19 lymph node spots could be detected in situ, 14 of which were fluorescently active and 18 of which were magnetically active. In two patients, no fluorescent LNs could be detected in situ. The separation of the LN samples resulted in a total number of 30 SLNs resected. Ex vivo measurements confirmed fluorescence in all but two magnetically active SLNs. One LN detected in situ with both modalities was subsequently shown to contain a metastasis. This study provides the first promising results of a bimodal, radiation-free sLND, combining the advantages of both the magnetic and fluorescence approaches.

A Systematic Review of New Imaging Technologies for Robotic Prostatectomy: From Molecular Imaging to Augmented Reality

New imaging technologies play a pivotal role in the current management of patients with prostate cancer. Robotic assisted radical prostatectomy (RARP) is a standard of care for localized disease and through the already imaging-based console subject of research towards combinations of imaging technologies and RARP as well as their impact on surgical outcomes. Therefore, we aimed to provide a comprehensive analysis of the currently available literature for new imaging technologies for RARP. On 24 January 2023, we performed a systematic review of the current literature on Pubmed, Scopus and Web of Science according to the PRISMA guidelines and Oxford levels of evidence. A total of 46 studies were identified of which 19 studies focus on imaging of the primary tumor, 12 studies on the intraoperative tumor detection of lymph nodes and 15 studies on the training of surgeons. While the feasibility of combined approaches using new imaging technologies including MRI, PSMA-PET CT or intraoperatively applied radioactive and fluorescent dyes has been demonstrated, the prospective confirmation of improvements in surgical outcomes is currently ongoing.

Exploring the Applications of Indocyanine Green in Robot-Assisted Urological Surgery: A Comprehensive Review of Fluorescence-Guided Techniques

This comprehensive review aims to explore the applications of indocyanine green (ICG) in robot-assisted urological surgery through a detailed examination of fluorescence-guided techniques. An extensive literature search was conducted in PubMed/MEDLINE, EMBASE and Scopus, using keywords such as "indocyanine green," "ICG", "NIRF", "Near Infrared Fluorescence", "robot-assisted", and "urology". Additional suitable articles were collected by manually cross-referencing the bibliography of previously selected papers. The integration of the Firefly^® technology in the Da Vinci^® robotic system has opened new avenues for the advancement and exploration of different urological procedures. ICG is a fluorophore widely used in near-infrared fluorescence-guided techniques. The synergistic combination of intraoperative support, safety profiles and widespread availability comprises an additional asset that empowers ICG-guided robotic surgery. This overview of the current state of the art illustrates the potential advantages and broad applications of combining ICG-fluorescence guidance with robotic-assisted urological surgery.

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.

Sentinel Lymph Node Techniques in Urologic Oncology: Current Knowledge and Application

Lymph node (LN) metastases have a significant negative impact on the prognosis of urological malignancies. Unfortunately, current imaging modalities are insufficient when it comes to detecting micrometastases; thus, surgical LN removal is commonly used. However, there is still no established ideal lymph node dissection (LND) template, leading to unnecessary invasive staging and the possibility of missing LN metastases located outside the standard template. To address this issue, the sentinel lymph node (SLN) concept has been proposed. This technique involves identifying and removing the first group of draining LNs, which can accurately stage cancer. While successful in breast cancer and melanoma, the SLN technique in urologic oncology is still considered experimental due to high false-negative rates and lack of data in prostate, bladder, and kidney cancer. Nevertheless, the development of new tracers, imaging modalities, and surgical techniques may improve the potential of the SLN procedures in urological oncology. In this review, we aim to discuss the current knowledge and future contributions of the SLN procedure in the management of urological malignancies.

Sentinel Lymph Node Biopsy in Prostate Cancer Patients: Results From an Injection Technique Targeting the Index Lesion in the Prostate Gland

Objectives

To determine the accuracy of nodal staging in patients with prostate cancer (PCa) when ^99mTc-nanocolloid radiotracer is injected into an index lesion (IL).

Methods

This prospective study was conducted at our institution between June 2016 and October 2020. It included 64 patients with localized PCa with at least a 5% possibility for lymph node involvement in the Memorial Sloan Kettering Cancer Center nomogram, suitable for surgical treatment. All patients underwent magnetic resonance imaging (MRI) with IL and were pathologically confirmed. The day before surgery, transrectal ultrasound-guided injection (TRUS) of ^99mTc-nanocolloid into the IL was performed. Surgical procedures included radical prostatectomy (RP), sentinel lymph node biopsy (SLNB), and extended pelvic lymphadenectomy (ePLND). Analysis was performed, including histopathological findings of RP, ePLND, and SLNB. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), false negative (FN), false positive (FP), diagnostic yield, and non-diagnostic rate were calculated.

Results

A total of 1,316 lymph nodes were excised, including 1,102 from the ePLND (83.7%) and 214 (16.3%) sentinel lymph nodes (SLN). 26 SLN were dissected outside the ePLND template. The final pathology demonstrated 46 (3.5%) lymph node metastasis, 31 (67.4%) in the SLNB and 15 (32.6%) in the non-SLN ePLND. At the patient level, 18 (28.1%) patients had pN1. With a mean follow-up of 33.1 months, 4/19 (21.1%) pN1 patients had undetectable PSA, and 3/19 (15.8%) had a PSA < 0.1 ng/mL. Lymph node dissection included 20.6 lymph nodes per patient (IQR 15–24.2), with 3.3 SLNB nodes per patient (IQR 2–4.2). PPV and NPV were 100 and 97.8%, respectively. Sensitivity and specificity were 94.4 and 100%, respectively. FN was 5.5% and FP was 4.3%. Diagnostic yields were 95.3% and the non-diagnostic rate was 4.7%.

Conclusion

Radiotracer injection into the prostate IL offers promising results for staging purposes in cases in which ePLND is considered. Negative SLNB is a predictor of negative ePLND. Patients with a limited burden of nodal metastasis have a significant chance of remaining free of biochemical recurrence at mid-term follow-up.

Predictive ability of prebiopsy magnetic resonance imaging and biopsy for side-specific negative lymph node metastasis at radical prostatectomy

BACKGROUND

Prostate cancer localization is reportedly associated with the laterality of lymph node metastasis. Thus, it may be feasible to predict side-specific lymph node metastasis (LNM) at radical prostatectomy (RP). To investigate whether multiparametric magnetic resonance imaging and biopsy findings can predict side-specific negative LNM and to explore the feasibility of unilateral lymph node dissection (LND) at RP.

METHODS

A total of 500 patients who were diagnosed with prostate cancer with prebiopsy multiparametric magnetic resonance imaging of the prostate and subsequent prostate biopsy and who underwent RP and extended LND without neoadjuvant treatment were enrolled. Multiparametric magnetic resonance imaging, biopsy findings, and LNM were assessed for each side. The negative predictive value (NPV) of multiparametric magnetic resonance imaging or biopsy or both for ipsilateral LNM was examined.

RESULTS

LNM was found in 9.2% (46/500) and 15.6% (28/180) of patients in the overall and high-risk cohorts, respectively. Magnetic resonance imaging and biopsy findings were negative in 408 and 262 sides, respectively, in the overall cohort and 144 and 100 sides, respectively, in the high-risk cohort. The NPVs of magnetic resonance imaging, biopsy, and both for ipsilateral LNM were 98.3%, 98.5%, and 99.1%, respectively, in the overall cohort, and 95.8%, 97.1%, and 97.6%, respectively, in the high-risk cohort.

CONCLUSIONS

Unilateral LND may be indicated based on side-specific LNM risk as assessed by prebiopsy multiparametric magnetic resonance imaging and biopsy.

Anatomical Fundamentals and Current Surgical Knowledge of Prostate Anatomy Related to Functional and Oncological Outcomes for Robotic-Assisted Radical Prostatectomy

Context

Meticulous knowledge about the anatomy of the prostate and surrounding tissue represents a crucial and mandatory requirement during radical prostatectomy for reliable oncological and excellent replicable, functional outcomes. Since its introduction two decades ago, robotic-assisted laparoscopic radical prostatectomy (RALP) has evolved to become the predominant surgical approach in many industrialized countries.

Objective

To provide and highlight currently available literature regarding prostate anatomy and to help in improving oncological and functional outcomes in RALP.

Methods/Evidence Acquiring

PubMed database was searched using the following keywords: "robotic-assisted radical prostatectomy," "anatomy," "neurovascular bundle," "nerve," "periprostatic fascia," "pelvis," "sphincter," "urethra," "urinary incontinence," and "erectile dysfunction." Relevant articles and book chapters were critically reviewed and if eligible, they were included in this review.

Results

New evidence in regards to prostatic anatomy and surgical approaches in RALP has been reported in recent years. Besides detailed anatomical studies investigating the meticulous structure of the fascial structures surrounding the prostate and neurovascular bundle preservation, debate about the optimal RALP approach is still ongoing, inspired by recent publications presenting promising functional outcomes following modifications in surgical approaches.

Conclusions

This review provides a detailed overview of the current knowledge of prostate anatomy, its surrounding tissue, and its influence on key surgical step development for RALP.

The impact of drainage pathways on the detection of nodal metastases in prostate cancer: a phase II randomized comparison of intratumoral vs intraprostatic tracer injection for sentinel node detection

INTRODUCTION

Previous studies indicated that location and amount of detected sentinel lymph nodes (SLNs) in prostate cancer (PCa) are influenced where SLN-tracer is deposited within the prostate. To validate whether intratumoral (IT) tracer injection helps to increase identification of tumor-positive lymph nodes (LNs) better than intraprostatic (IP) tracer injection, a prospective randomized phase II trial was performed.

METHODS

PCa patients with a > 5% risk of lymphatic involvement were randomized between ultrasound-guided transrectal injection of indocyanine green-[^99mTc]Tc-nanocolloid in 2 depots of 1 mL in the tumor (n = 55, IT-group) or in 4 depots of 0.5 mL in the peripheral zone of the prostate (n = 58, IP-group). Preoperative lymphoscintigraphy and SPECT/CT were used to define the location of the SLNs. SLNs were dissected using combination of radio- and fluorescence-guidance, followed by extended pelvic LN dissection and robot-assisted radical prostatectomy. Outcome measurements were number of tumor-bearing SNs, tumor-bearing LNs, removed nodes, number of patients with nodal metastases, and metastasis-free survival (MFS) of 4-7-year follow-up data.

RESULTS

IT-injection did not result in significant difference of removed SLNs (5.0 vs 6.0, p = 0.317) and histologically positive SLNs (28 vs 22, p = 0.571). However, in IT-group, the SLN-positive nodes were 73.7% of total positive nodes compared to 37.3% in IP-group (p = 0.015). Moreover, significantly more node-positive patients were found in IT-group (42% vs 24%, p = 0.045), which did not result in worse MFS. In two patients (3.6%) from whom the IT-tracer injection only partly covered intraprostatic tumor spread, nodal metastases in ePLND without tumor-positive SNs were yielded.

CONCLUSIONS

The percentage-positive SLNs found after IT-injection were significantly higher compared to IP-injection. Significantly more node-positive patients were found using IT-injection, which did not affect MFS. IT-injection failed to detect nodal metastases from non-index satellite lesions. Therefore, we suggest to combine IT- and IP-tracer injections in men with visible tumor on imaging.

Performance of Indocyanine Green Fluorescence for Detecting Lymph Node Metastasis in Prostate Cancer: A Systematic Review and Meta-analysis

PURPOSE

The use of sentinel lymph node dissection in several cancers has been gaining attention with the emergence of indocyanine green fluorescence. We performed a meta-analysis to assess the diagnostic performance of indocyanine green fluorescence in detecting lymph node metastasis in prostate cancer patients.

METHODS

A literature search was conducted using PubMed, Cochrane Library, and SCOPUS on November 30, 2020, to identify eligible studies. Studies were eligible if they investigated the diagnostic performance of indocyanine green fluorescence before pelvic lymph node dissection in prostate cancer patients and reported the number of true positives, false positives, false negatives, and true negatives on lymph node-based analysis in comparison to histopathologic findings in the dissected specimen.

RESULTS

Our systematic review covered 11 studies published between 2011 and 2020, with 519 patients, and our meta-analysis included 9 studies with 479 patients. Based on lymph node analysis of indocyanine green fluorescence, the results showed pooled sensitivity and specificity at 0.75 (95% confidence interval [CI] 0.49 to 0.90) and 0.66 (95% CI 0.61 to 0.70), respectively. The diagnostic odds ratio was 6.0 (95%CI 2 to 21). Several lymphatic drainage routes also showed sentinel lymph nodes localized outside the ordinal pelvic lymph node template.

CONCLUSIONS

We noted relatively low diagnostic performance for lymph node metastasis, suggesting that indocyanine fluorescence may not currently be a viable alternative to pelvic lymph node dissection in prostate cancer patients. However, this technique shows novel lymphatic drainage routes and underscores the importance of lymph nodes not removed in ordinary dissection.

Interventional nuclear medicine: a focus on radioguided intervention and surgery

Within interventional nuclear medicine (iNM) a prominent role is allocated for the sub-discipline of radioguided surgery. Unique for this discipline is the fact that an increasing number of clinical indications (e.g. lymphatic mapping, local tumor demarcation and/or tumor receptor targeted applications) have been adopted into routine care. The clinical integration is further strengthened by technical innovations in chemistry and engineering that enhance the translational potential of radioguided procedures in iNM. Together, these features not only ensure ongoing expansion of iNM but also warrant a lasting clinical impact for the sub-discipline of radioguided surgery.

NRG Oncology Updated International Consensus Atlas on Pelvic Lymph Node Volumes for Intact and Postoperative Prostate Cancer

PURPOSE

In 2009, the Radiation Therapy Oncology Group (RTOG) genitourinary members published a consensus atlas for contouring prostate pelvic nodal clinical target volumes (CTVs). Data have emerged further informing nodal recurrence patterns. The objective of this study is to provide an updated prostate pelvic nodal consensus atlas.

METHODS AND MATERIALS

A literature review was performed abstracting data on nodal recurrence patterns. Data were presented to a panel of international experts, including radiation oncologists, radiologists, and urologists. After data review, participants contoured nodal CTVs on 3 cases: postoperative, intact node positive, and intact node negative. Radiation oncologist contours were analyzed qualitatively using count maps, which provided a visual assessment of controversial regions, and quantitatively analyzed using Sorensen-Dice similarity coefficients and Hausdorff distances compared with the 2009 RTOG atlas. Diagnostic radiologists generated a reference table outlining considerations for determining clinical node positivity.

RESULTS

Eighteen radiation oncologists' contours (54 CTVs) were included. Two urologists' volumes were examined in a separate analysis. The mean CTV for the postoperative case was 302 cm3, intact node positive case was 409 cm3, and intact node negative case was 342 cm3. Compared with the original RTOG consensus, the mean Sorensen-Dice similarity coefficient for the postoperative case was 0.63 (standard deviation [SD] 0.13), the intact node positive case was 0.68 (SD 0.13), and the intact node negative case was 0.66 (SD 0.18). The mean Hausdorff distance (in cm) for the postoperative case was 0.24 (SD 0.13), the intact node positive case was 0.23 (SD 0.09), and intact node negative case was 0.33 (SD 0.24). Four regions of CTV controversy were identified, and consensus for each of these areas was reached.

CONCLUSIONS

Discordance with the 2009 RTOG consensus atlas was seen in a group of experienced NRG Oncology and international genitourinary radiation oncologists. To address areas of variability and account for new data, an updated NRG Oncology consensus contour atlas was developed.