Mapping of pelvic lymph node metastases in prostate cancer

MRI-detected extranodal extension as a marker of prostate cancer aggressiveness

OBJECTIVE

Extranodal extension (ENE) is a histological marker of aggressiveness for various cancers. We evaluated if clinical ENE, detected by Magnetic Resonance Imaging, can also serve as a biological marker of Prostate Cancer (PCa) aggressiveness.

MATERIALS AND METHODS

This retrospective, single-center study analyzed patients diagnosed with PCa and had MRI on a 3-T scanner from January 2013 to December 2017. After exclusions, 461 patients were included and divided into: Group 1, no lymph node involvement (LNI), Group 2 (LNI without ENE), and Group 3 (LNI and ENE). Two experienced radiologists assessed the MRI scans for primary lesion characteristics, LNI and ENE. Reproducibility assessment was calculated for ENE and PI-RADS. Clinical outcomes, including Overall Survival (OS), Specific Survival Rate (SSR), and Progression-Free Survival (PFS), were analyzed.

RESULTS

Group 1 included 410 patients, Group 2, 32 patients, and Group 3, 19 patients. The prevalence of ENE was 4.1%. Significant differences between groups were observed for age, PSA, dPSA, ISUP scores, clinical risk stratification, and staging (all p < 0.01). The Kappa coefficient for ENE was 0.75 (95% CI: 0.56-0.90), and 0.48 (0.14-1.0) for PI-RADS. Cox proportional hazards model showed PSA (HR: 1.009; 95% CI = 1.003-1.015, p < 0.01) and ENE (HR: 8.50; 1.76-40.98, p < 0.01) were associated with SSR, and both ENE (HR: 8.18; 2.34-28.58, p < 0.01) and LNI (HR: 5.99, 1.97-18.17, p < 0.01) were linked to poor PFS.

CONCLUSION

MRI-detected ENE, despite low prevalence, is a predictor of SSR and PFS in PCa. These findings support ENE as an independent prognostic marker. Further prospective, multi-institutional studies are required to validate these results.

KEY POINTS

Question Pathological extranodal extension (pENE) has been described as a marker of worrisome prognosis in prostate cancer (PCa), but clinical ENE has not been evaluated as a marker of prognosis in PCa. Findings MRI-detected clinical ENE, had a low prevalence in our cohort (4.1%), but it was a predictor of specific survival rate and progression-free survival. Clinical relevance MRI-detected clinical ENE, a reproducible imaging feature, may serve as a non-invasive biomarker for aggressive prostate cancer. It correlates with poorer progression-free survival and specific survival rates, offering valuable prognostic insights for patient management.

Metastatic lymph nodes outside the extended lymphadenectomy template correlate with advanced staging but not grading in prostate cancer patients undergoing radical prostatectomy

PURPOSE

This study aimed to evaluate the impact of metastatic lymph nodes (LNs) outside the extended pelvic lymph node dissection (ePLND) template on oncological outcomes, staging, grading, and concomitant parameters in prostate cancer (PCa) patients undergoing radical prostatectomy (RP).

METHODS

Data from 860 patients with histologically confirmed, non-metastatic PCa who underwent RP between 2012 and 2022 were retrospectively analyzed. All specimens underwent detailed histopathological examination. Preoperative and postoperative clinicopathological data were collected and analyzed. Subgroup associations were evaluated using the Mann-Whitney U test and the Kruskal-Wallis test. Kendall's tau-b coefficient was employed to evaluate the association between two variables. All tests were performed using a two-tailed approach, with a p value of less than 0.05 considered statistically significant for differences between groups. Kaplan-Meier and Cox regression analyses assessed biochemical recurrence (BCR)-free survival based on lymph node invasion (LNI) (pN0 vs. pN1) and the presence of metastatic LNs outside the ePLND template.

RESULTS

Of the 860 patients, 613 underwent modified-ePLND. Among them, 122 (19.9%) were pN1, with 22 patients (18%) having metastatic LNs located outside the classical ePLND template. Patients with LNs beyond the ePLND template exhibited higher clinical T stages (p = 0.016) and a greater percentage of positive biopsy cores (p = 0.008). However, no correlation was observed with Gleason Grading Group (p = 0.491). Kaplan-Meier analysis showed that pN1 patients had higher BCR rates compared to pN0 patients, but this difference did not reach statistical significance (p = 0.174). Similarly, patients with metastatic LNs outside the ePLND template demonstrated a trend toward increased BCR risk, though this was not statistically significant (p = 0.140).

CONCLUSION

Metastatic LNs beyond the ePLND template correlate with more advanced tumor staging in PCa. However, they show no association with tumor grading. Their influence on BCR remains inconclusive, likely due to the small number of patients included in the BCR-associated analyses. Extended lymphadenectomy may enhance staging accuracy but must be weighed against the potential for increased surgical morbidity.

Imaging assessment of prostate cancer recurrence: advances in detection of local and systemic relapse

Prostate cancer (PCa) relapse, defined either by persistent PSA levels (after RP) or biochemical recurrence (BCR), is a common occurrence. The imaging evaluation of patients experiencing PCa relapse has undergone significant advancements in the past decade, notably with the introduction of new Positron Emission Tomography (PET) tracers such as Prostate-specific membrane antigen (PSMA), and the progress in functional Magnetic Resonance Imaging (MRI). This article will explore the role of traditional imaging, the evolution of MRI towards the development of the Prostate Magnetic Resonance Imaging for Local Recurrence Reporting (PI-RR) scoring system, and how next-generation imaging is enhancing diagnostic accuracy in the setting of PCa relapse, which is essential for adopting personalized strategies that may ultimately impact outcomes.

Reevaluating the Therapeutic Role of Pelvic Lymph Node Dissection in Robot-Assisted Radical Prostatectomy

INTRODUCTION

Extended pelvic lymph node dissection (PLND) is recommended for intermediate- and high-risk prostate cancer according to D'Amico risk classification, and there is evidence supporting its diagnostic value in staging. However, its therapeutic benefit remains unproven. We, therefore, aimed to evaluate the therapeutic significance of PLND in patients undergoing robot-assisted radical prostatectomy (RARP).

METHODS

We retrospectively analyzed 329 patients with intermediate- or high-risk prostate cancer (per D'Amico risk classification) who underwent RARP at two centers. Patients were divided into two groups: those who did not undergo lymph node dissection (no-PLND group) and those who underwent an extended PLND (extended-PLND group). After excluding patients who received neoadjuvant hormone therapy, 313 cases remained for analysis. Propensity score matching was performed to balance baseline characteristics, yielding 85 matched pairs. We compared prostate-specific antigen progression-free survival (PSA-PFS) and overall survival (OS) between the matched groups. Perioperative outcomes (complications, console time, and blood loss) were also compared.

RESULTS

Kaplan-Meier analysis showed no significant differences in PSA-PFS (p = 0.163) or OS (p = 0.323) between the extended-PLND and no-PLND groups after matching. Similarly, when stratified by risk category, PSA-PFS did not differ significantly between the two groups for either intermediate-risk or high-risk patients. Perioperative blood loss was similar between groups, but the no-PLND group had a significantly lower overall complication rate (5.1% vs. 30.4%, p < 0.001) and shorter median console time (160.2 vs. 230.5 min, p < 0.001) than the extended-PLND group. Notably, no Grade 3-4 complications (Clavien-Dindo) occurred in the no-PLND group, compared to 11 cases in the extended-PLND group.

CONCLUSION

In intermediate- and high-risk prostate cancer, performing an extended PLND during RARP did not improve biochemical recurrence-free or OS, suggesting minimal therapeutic benefit.

Japanese expert consensus on the standardization of robot-assisted pelvic lymph node dissection in urological surgery: Extent of pelvic lymph node and surgical technique

Pelvic lymph node dissection (PLND) is important for accurate staging and prognosis of prostate and/or bladder cancer. Several guidelines recommend extended PLND for patients with these cancers. However, the therapeutic benefits of extended PLND are unclear. One major reason is that the extent of PLND is not clearly defined. Thus, the working group for standardization of robot-assisted PLND, including nine experienced urologists for PLND in Japan, was launched in January 2023 by the Japanese Society of Endourology and Robotics. This study summarized the discussions to define the individual extent of PLND in urological surgery in a consensus meeting among these experienced urologists. The consensus meeting determined the extent of PLND based on arteries (veins) and anatomical membrane structures rather than a vague concept or approach toward PLND. This concept is expected to allow surgeons to implement the same extent of PLND. Finally, after a total of 10 online web conferences were held, we determined the extent of PLND for the obturator lymph node (LN) area, the internal iliac LN area, the external and common iliac LN area, and the presacral LN area according to the above rules. The extent of PLND suggested here currently does not have a clear therapeutic rationale. Therefore, the extent of our proposed PLND is by no means mandatory. We hope our definition of the extent of PLND will be supported by further evidence of therapeutic benefits for urologic cancers.

French AFU Cancer Committee Guidelines - Update 2024-2026: Prostate cancer - Diagnosis and management of localised disease

OBJECTIVE

The aim of the Oncology Committee of the French Urology Association is to propose updated recommendations for the diagnosis and management of localized prostate cancer (PCa).

METHODS

A systematic review of the literature from 2022 to 2024 was conducted by the CCAFU on the elements of diagnosis and therapeutic management of localized PCa, evaluating references with their level of evidence.

RESULTS

The recommendations set out the genetics, epidemiology and diagnostic methods of PCa, as well as the concepts of screening and early detection. MRI, the reference imaging test for localized cancer, is recommended before prostate biopsies are performed. Molecular imaging is an option for disease staging. Performing biopsies via the transperineal route reduces the risk of infection. Active surveillance is the standard treatment for tumours with a low risk of progression. Therapeutic methods are described in detail, and recommended according to the clinical situation.

CONCLUSION

This update of French recommendations should help to improve the management of localized PCa.

Evaluation of complications and biochemical recurrence rates after (super) extended lymph node dissection during radical prostatectomy

OBJECTIVE

To evaluate the effectiveness of extended (e-PLND) and super-extended pelvic lymph node dissection (se-PLND) during robot-assisted radical prostatectomy (RARP) by examining lymph node (LN) yield, complications, LN metastasis, and biochemical recurrence (BCR) incidence.

METHODS

Between January 2016 and January 2020, 354 consecutive patients with > 5% risk of lymph node involvement (LNI), as predicted by the Memorial Sloan Kettering Cancer Center nomogram, underwent RARP with (s)e-PLND at a high-volume center. The e-PLND involved removing fibrofatty lymphatic tissue around the obturator fossa, internal iliac region, and external iliac vessels. The se-PLND, performed at the discretion of the surgeons, also included lymph nodes from the pre-sacral and common iliac regions. Outcomes included histopathological findings by anatomical region; complications; and BCR incidence during follow-up.

RESULTS

The median LNI risk was 18% (IQR 9-31%). A median of 22 LN (IQR 16-28) were removed, with se-PLND yielding a higher number: 25 (IQR 20-32) compared to e-PLND: 17 (IQR 13-24) (p < 0.001). pN1 disease was detected in 22% of patients overall, higher in se-PLND (29%) than e-PLND (14%) (p < 0.001). Of metastatic LNs, 14% were situated outside the e-PLND template. Operation time was longer for se-PLND, but perioperative complications were similar between both groups. After a median follow-up of 24 months (IQR 7-33), BCR incidence was comparable between the two groups.

CONCLUSION

Compared to standard extended pelvic lymph node dissection (PLND), super extended PLND increases lymph node yield and removal of metastatic deposits but does not contribute to progression free survival at mid-term.

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.

Prostate-Specific Membrane Antigen-Targeted Radioguided Pelvic Lymph Node Dissection in Newly Diagnosed Prostate Cancer Patients with a Suspicion of Locoregional Lymph Node Metastases: The DETECT Trial

Prostate-specific membrane antigen (PSMA)-targeted radioguided surgery (RGS) aims to optimize the peroperative detection and removal of PSMA-avid lymph node (LN) metastases (LNMs) and has been described in patients with recurrent prostate cancer (PCa). In newly diagnosed PCa patients undergoing pelvic LN dissections, PSMA RGS could guide the urologist toward PSMA-expressing LNMs as identified on preoperative 18F-PSMA PET/CT imaging. The objective was to evaluate the safety and feasibility of 111In-PSMA RGS in primary PCa patients with one or more suggestive LNs on preoperative 18F-PSMA PET/CT. Methods: This prospective, phase I/II study included 20 newly diagnosed PCa patients with at least 1 suggestive LN on preoperative 18F-PSMA PET/CT. PSMA RGS was performed 24 h after 111In-PSMA-I&T administration, and postoperative 18F-PSMA PET/CT was performed to verify successful removal of the suggestive lesions. The primary endpoint was determination of the safety and feasibility of 111In-PSMA RGS. Safety was assessed by monitoring adverse events. Feasibility was described as the possibility to peroperatively detect suggestive LNs as identified on preoperative imaging. Secondary outcomes included the accuracy of 111In-PSMA RGS compared with histopathology, tumor- and lesion-to-background ratios, and biochemical recurrence. Results: No tracer-related adverse events were reported. In 20 patients, 43 of 49 (88%) 18F-PSMA PET-suggestive lesions were successfully removed. 111In-PSMA RGS facilitated peroperative identification and resection of 29 of 49 (59%) RGS-target lesions, of which 28 (97%) contained LNMs. Another 14 of 49 (29%) resected LNs were not detected with 111In-PSMA RGS, of which 2 contained metastases. Conclusion: 111In-PSMA RGS is a safe and feasible procedure that allows peroperative detection of 18F-PSMA PET/CT-suggestive lesions in newly diagnosed PCa patients. The use of a radioactive PSMA tracer and a detection device (γ-probe) during surgery helps in identifying LNs that were suggestive of PCa metastases on the 18F-PSMA PET/CT before surgery and thus may improve the peroperative identification and removal of these LNs.

The role and controversy of pelvic lymph node dissection in prostate cancer treatment: a focused review

Pelvic lymph node dissection (PLND) is commonly performed alongside radical prostatectomy. Its primary objective is to determine the lymphatic staging of prostate tumors by removing lymph nodes involved in lymphatic drainage. This aids in guiding subsequent treatment and removing metastatic foci, potentially offering significant therapeutic benefits. Despite varying recommendations from clinical practice guidelines across countries, the actual implementation of PLND is inconsistent, partly due to debates over its therapeutic value. While high-quality evidence supporting the superiority of PLND in oncological outcomes is lacking, its role in increasing surgical time and risk of complications is well-recognized. Despite these concerns, PLND remains the gold standard for lymph node staging in prostate cancer, providing invaluable staging information unattainable by other techniques. This article reviews PLND's scope, guideline perspectives, implementation status, oncologic and non-oncologic outcomes, alternatives, and future research needs.

A Multicentre Clinical Trial Evaluating a Drop-in Gamma Probe for Minimally Invasive Sentinel Lymph Node Dissection in Prostate Cancer

BACKGROUND

This study evaluated the safety and performance of a drop-in gamma probe for prostate cancer (PCa) sentinel lymph node biopsy (SeLNB) in a prospective, open-label, multicentre, single-arm clinical trial.

OBJECTIVE

The main objective was to determine the sentinel lymph node (SeLN) detection rate with the drop-in gamma probe system. The secondary objectives were overall performance and safety.

DESIGN, SETTING, AND PARTICIPANTS

At three European centres, patients received an ultrasound-guided systemic and tumour-targeted injection of [99mTc]Tc-nanocolloid followed by planar lymphoscintigraphy and/or single-photon emission computerised tomography. The next day, manual laparoscopic or robot-assisted radical prostatectomy was performed, including SeLN dissection (SeLND) and extended pelvic lymph node dissection (ePLND).

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

SeLNs were detected with the drop-in probe and a rigid laparoscopic gamma probe (RLGP). The primary endpoint of the study was the SeLND rate defined as the percentage of patients with at least one SeLN detected in vivo by the drop-in probe. The secondary endpoints included diagnostic performance, ease of SeLN detection, number of SeLNs detected, and safety. The first two patients at each site (six in total) were used for familiarisation.

RESULTS AND LIMITATIONS

A total of 27 patients were included in the main analysis. SENSEI successfully detected at least one SeLN in all 27 patients, resulting in a detection rate of 100% (95% confidence interval 87.2-100%). The total number of SeLNs identified with SENSEI was 85 (median three SeLNs per patient, range 1-6); of these 85 SeLNs, 12 were located outside of the ePLND template. In the nine patients in whom the RLGP was used, SENSEI detected two SeLNs that could not be detected with the RLGP due to manoeuvrability restrictions. Ten of the 27 patients were pN1; four patients had a false-negative SeLNB. No adverse events or complications were related to the use of the drop-in probe.

CONCLUSIONS

The study demonstrated that the drop-in gamma probe meets the performance and safety requirements for SeLNB in PCa. The device provided improved manoeuvrability and SeLN detection compared with the conventional RLGP.

PATIENT SUMMARY

A novel device was tested for detecting sentinel lymph nodes during minimally invasive surgery for prostate cancer. In this first evaluation, the performance and safety of the device were evaluated positively.

The role of nuclear medicine tracers for prostate cancer surgery: from preoperative to intraoperative setting

PURPOSE OF REVIEW

There has been a growing interest in the use of novel molecular imaging modalities for the management of prostate cancer (PCa), spanning from diagnostic to therapeutic settings. The aim of this review is to provide a comprehensive overview of recently published studies investigating the use of novel nuclear medicine tracers across different stages of PCa management.

RECENT FINDINGS

Emerging evidence supports the use of molecular imaging for preoperative staging of PCa, where prostate-specific membrane antigen (PSMA) PET has shown superior accuracy compared to conventional imaging for the detection of nodal and distant metastases, which needs to be translated to new risk stratification. A role for PSMA PET has been proposed for PCa diagnosis, with local activity associated with histology. Surgical guidance, using either visual feedback or gamma-ray detectors to identify tissues with accumulated radio-labeled tracers, may improve the ability to resect locoregional diseases and thus maximize oncological control. PSMA targeted therapy (Lu-PSMA) has been mainly investigated in the castration-resistant setting, but might have a role in earlier settings such as neoadjuvant treatment.

SUMMARY

Novel molecular imaging using PSMA-based tracers could significantly improve PCa management in the diagnosis, staging, and intraoperative guidance settings, potentially leading to personalized and effective treatment decisions.

Diagnostic and therapeutic impact of PET/CT with 18F-DCFPyL versus 18F-Fluorocholine in initial staging of intermediate-/high-risk prostate cancer: a pilot study

AIM

To assess the diagnostic and therapeutic impact of PET/CT with 18F-DCFPyL with respect to 18F-Fluorocholine in initial staging of intermediate-/high-risk prostate cancer (PCa).

MATERIAL AND METHODS

Patients with recent diagnosis of intermediate-/high-risk PCa without androgen deprivation therapy and previous 18F-Fluorocholine-PET/CT (negative for extraprostatic disease or with oligometastatic disease) were referred to 18F-DCFPyL-PET/CT. Patients' disease characteristic as grade group, D'Amico risk category (intermediate/high), prostate-specific antigen (PSA) closest to PET/CTs and its kinetics were obtained. The overall detection rate (DR) and molecular imaging TNM (miTNM) stage according to the prostate cancer molecular imaging standardized evaluation (PROMISE) criteria were assessed for both radiotracers, and their concordance (Kappa coefficient) was analyzed. The diagnostic and therapeutic impact of 18F-DCFPyL with respect to 18F-Fluorocholine was evaluated.

RESULTS

Fifty-eight patients were analyzed (84.5% high-risk). 18F-Fluorocholine showed a higher DR than 18F-DCFPyL of prostate gland involvement (100% versus 93.1%) and pelvic node disease (37.9% versus 31%; k = 0.436, p = 0.001). On the other hand, 18F-DCFPyL-PET/CT showed a higher DR of metastatic disease than 18F-Fluorocholine-PET/CT, 9/58 patients (15.5%): 3 M1a, 5 M1b and 1 M1c) versus 5/58 (8.6%) patients: 1 M1a and 4 M1b), k = 0.426; p = 0.001. No significant association was found between clinical characteristics (grade group, risk category, PSA level and kinetic) and 18F-Fluorocholine or 18F-DCFPyL results. The results of 18F-DCFPyL-PET/CT modified the previously planned treatment compared to 18F-Fluorocholine-PET/CT in 13 patients (22.4%).

CONCLUSIONS

18F-Fluorocholine and 18F-DCFPyL PET/CT showed a similar DR of prostate gland and lymph node involvement, although with moderate concordance for the latter. 18F-DCFPyL was superior to 18F-Fluorocholine in detecting regional and distant metastasis with a therapeutic impact in one of every five patients.

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 Node Procedure to Select Clinically Localized Prostate Cancer Patients with Occult Nodal Metastases for Whole Pelvis Radiotherapy

Background

Accurate identification of men who harbor nodal metastases is necessary to select patients who most likely benefit from whole pelvis radiotherapy (WPRT). Limited sensitivity of diagnostic imaging approaches for the detection of nodal micrometastases has led to the exploration of the sentinel lymph node biopsy (SLNB).

Objective

To evaluate whether SLNB can be used as a tool to select pathologically node-positive patients who likely benefit from WPRT.

Design setting and participants

We included 528 clinically node-negative primary prostate cancer (PCa) patients with an estimated nodal risk of >5% treated between 2007 and 2018.

Intervention

A total of 267 patients were directly treated with prostate-only radiotherapy (PORT; non-SLNB group), while 261 patients underwent SLNB to remove lymph nodes directly draining from the primary tumor prior to radiotherapy (SLNB group); pN0 patients were treated with PORT, while pN1 patients were offered WPRT.

Outcome measurements and statistical analysis

Biochemical recurrence-free survival (BCRFS) and radiological recurrence-free survival (RRFS) were compared using propensity score weighted (PSW) Cox proportional hazard models.

Results and limitations

The median follow-up was 71 mo. Occult nodal metastases were found in 97 (37%) SLNB patients (median metastasis size: 2 mm). Adjusted 7-yr BCRFS rates were 81% (95% confidence interval [CI] 77-86%) in the SLNB group and 49% (95% CI 43-56%) in the non-SLNB group. The corresponding adjusted 7-yr RRFS rates were 83% (95% CI 78-87%) and 52% (95% CI 46-59%), respectively. In the PSW multivariable Cox regression analysis, SLNB was associated with improved BCRFS (hazard ratio [HR] 0.38, 95% CI 0.25-0.59, p < 0.001) and RRFS (HR 0.44, 95% CI 0.28-0.69, p < 0.001). Limitations include the bias inherent to the study's retrospective nature.

Conclusions

SLNB-based selection of pN1 PCa patients for WPRT was associated with significantly improved BCRFS and RRFS compared with (conventional) imaging-based PORT.

Patient summary

Sentinel node biopsy can be used to select patients who will benefit from the addition of pelvis radiotherapy. This strategy results in a longer duration of prostate-specific antigen control and a lower risk of radiological recurrence.

The application of indocyanine green in guiding prostate cancer treatment

Objective

Indocyanine green (ICG) with near-infrared fluorescence absorption is approved by the United States Food and Drug Administration for clinical applications in angiography, blood flow evaluation, and liver function assessment. It has strong optical absorption in the near-infrared region, where light can penetrate deepest into biological tissue. We sought to review its value in guiding prostate cancer treatment.

Methods

All related literature at PubMed from January 2000 to December 2020 were reviewed.

Results

Multiple preclinical studies have demonstrated the usefulness of ICG in identifying prostate cancer by using different engineering techniques. Clinical studies have demonstrated the usefulness of ICG in guiding sentinel node dissection during radical prostatectomy, and possible better preservation of neurovascular bundle by identifying landmark prostatic arteries. New techniques such as adding fluorescein in additional to ICG were tested in a limited number of patients with encouraging result. In addition, the use of the ICG was shown to be safe. Even though there are encouraging results, it does not carry sufficient sensitivity and specificity in replacing extended pelvic lymph node dissection during radical prostatectomy.

Conclusion

Multiple preclinical and clinical studies have shown the usefulness of ICG in identifying and guiding treatment for prostate cancer. Larger randomized prospective studies are warranted to further test its usefulness and find new modified approaches.

Pelvic lymph node dissection in prostate and bladder cancers

Prostate cancer and bladder cancer accounts for approximately 13.5% and 3% of all male cancers and all newly diagnosed cancers (regardless sex), respectively. Thus, these cancers represent a major health and economic burden globally. The knowledge of lymph node status is an integral part of the management of any solid tumor. In the urological field, pelvic lymph node dissection (PLND) is of paramount importance in the diagnosis, management, and prognosis of prostate and bladder cancers. However, PLND may be associated with several comorbidities. In this narrative review, the most recent updates concerning the patterns and incidence of lymph node metastasis, the role of different imaging studies and nomograms in determining patients' eligibility for PLND, and the anatomical templates of PLND in urologic patients with bladder or prostate cancer will be discussed.

Diagnostic Value of Radio-Guided Sentinel Node Detection in Patients with Prostate Cancer Undergoing Radical Prostatectomy with Modified-Extended Lymphadenectomy

Background. In many malignancies, sentinel lymph node dissection (SLND) is being used as a nodal staging tool. We prospectively evaluated the diagnostic value of radio-guided sentinel lymph node (SLN) detection in patients with prostate cancer (PCa). This study aimed to investigate the reliability of the radio-guided SLN detection technique for perioperative localization of LNs metastases as well as to map lymphatic drainage patterns of the prostate. Methods. Forty-three patients with intermediate- or high-risk cN0cM0 PCa at conventional imaging underwent radical prostatectomy with modified-extended pelvic lymph node dissection (mePLND). A day before the planned surgery, a Tc-99m nanocolloid was injected into the prostate under the control of transrectal ultrasonography (TRUS). Preoperative single-photon emission computed tomography (SPECT-CT) imaging and intraoperative gamma-probe were used to identify SLNs. All positive lesions were excised, followed by mePLND. The excised lymph nodes (LNs) were then submitted for histopathological examination, which was used as a reference for the calculation of diagnostic parameters of the SLN technique for SPECT-CT and the intraoperative gamma-probe. Results. In total, 119 SLNs were detected preoperatively (SPECT-CT) and 118 intraoperatively (gamma-probe). The study revealed that both SLN detection techniques showed a sensitivity of 90% and a specificity of 6.06%. The negative predictive value (NPV) was 66.67%. SLN technique would have correctly staged nine of 10 patients, which is the same result as in the case of limited LND. However, it allowed the removal of all metastatic nodes only in four of them. SLND would have comprised 69.7% of preoperatively detected LNs, and removed 13 out of 19 positive LNs (68.42%), respectively. Conclusions. Radio-guided SLND has a low diagnostic rate and is a poor staging tool. ePLND remains the gold standard in nodal metastases assessment in PCa. Our study indicates that lymphatic drainage of the prostate and actual metastasis routes may vary significantly.

How Advanced Imaging Will Guide Therapeutic Strategies for Patients with Newly Diagnosed Prostate Cancer in the Years to Come

In recent years, clinical use of novel advanced imaging modalities in prostate cancer detection, staging, and therapy has intensified and is currently reforming clinical guidelines. In the future, advanced imaging technologies will continue to develop and become even more accurate, which will offer new opportunities for improving patient selection, surgical treatment, and radiotherapy, with the potential to guide prostate cancer therapy.

Impact of 18F-DCFPyL PET on Staging and Treatment of Unfavorable Intermediate or High-Risk Prostate Cancer

Background Data regarding 2-(3-{1-carboxy-5-[(6-[¹⁸F]fluoro-pyridine 3-carbonyl)-amino]-pentyl}-ureido)-pentanedioic acid (¹⁸F-DCFPyL) PET in primary staging of prostate cancer (PCa) are limited. Purpose To compare the performance of ¹⁸F-DCFPyL PET/CT or PET/MRI (PET) with bone scan and CT with or without multiparametric MRI (hereafter, referred to as conventional imaging) in the initial staging of men with unfavorable intermediate or high-risk PCa and to assess treatment change after PET. Materials and Methods This prospective study evaluated men with biopsy-proven, untreated, unfavorable intermediate or high-risk PCa with 0 to four metastases or equivocal for extensive metastases (more than four) who underwent PET between May 2018 and December 2020. The diagnostic performance of PET in detecting pelvic nodal and distant metastases was compared with conventional imaging alone. Metastatic sites at conventional imaging and PET were compared with a composite reference standard including histopathologic analysis, correlative imaging, and/or clinical and biochemical follow-up. The intended treatment before PET was compared with the treatment plan established after performing PET. Detection rate, sensitivity, and specificity of conventional imaging and PET were compared by using McNemar exact test on paired proportions. Results The study consisted of 108 men (median age, 66 years; IQR, 61-73 years) with no metastases (n = 84), with oligometastases (four or fewer metastases; 22 men), or with equivocal findings for extensive metastases (n = 2). Detection rates at PET and conventional imaging for nodal metastases were 34% (37 of 108) and 11% (12 of 108) (P < .001), respectively, and those for distant metastases were 22% (24 of 108) and 10% (11 of 108) (P = .02), respectively. PET altered stage in 43 of 108 (40%) and treatment in 24 of 108 (22%) men. The most frequent treatment change was from systemic to local-regional therapy in 10 of 108 (9%) and from local-regional to systemic therapy in nine of 108 (8%) men. Equivocal findings were encountered less frequently with PET (one of 108; 1%) than with conventional imaging (29 of 108; 27%). Conclusion Initial staging with 2-(3-{1-carboxy-5-[(6-[¹⁸F]fluoro-pyridine 3-carbonyl)-amino]-pentyl}-ureido)-pentanedioic acid (¹⁸F-DCFPyL) PET after conventional imaging (bone scan and CT with or without multiparametric MRI) helped to detect more nodal and distant metastases than conventional imaging alone and changed treatment in 22% of men. Clinical trial registration no. NCT03535831, NCT03718260 © RSNA, 2022 Online supplemental material is available for this article. See also the editorial by Jadvar in this issue.

Patients with Positive Lymph Nodes after Radical Prostatectomy and Pelvic Lymphadenectomy-Do We Know the Proper Way of Management?

Lymph node invasion in prostate cancer is a significant prognostic factor indicating worse prognosis. While it significantly affects both survival rates and recurrence, proper management remains a controversial and unsolved issue. The thorough evaluation of risk factors associated with nodal involvement, such as lymph node density or extracapsular extension, is crucial to establish the potential expansion of the disease and to substratify patients clinically. There are multiple strategies that may be employed for patients with positive lymph nodes. Nowadays, therapeutic methods are generally based on observation, radiotherapy, and androgen deprivation therapy. However, the current guidelines are incoherent in terms of the most effective management approach. Future management strategies are expected to make use of novel diagnostic tools and therapies, such as photodynamic therapy or diagnostic imaging with prostate-specific membrane antigen. Nevertheless, this heterogeneous group of men remains a great therapeutic concern, and both the clarification of the guidelines and the optimal substratification of patients are required.

Effect of pelvic lymph node dissection and its extent on oncological outcomes in intermediate-risk prostate cancer patients: A multicenter study of the Turkish Uro-oncology Association

BACKGROUND

Pelvic lymph node dissection (PLND) is the gold standard method for lymph node staging in prostate cancer. We aimed to evaluate the effect of PLND combined with radical prostatectomy (RP) on oncological outcomes in D'Amico intermediate-risk prostate cancer (IRPC) patients.

METHODS

Patients with D'Amico IRPC were included in the study. In the overall cohort and subgroups (biopsy International Society of Urological Pathology [ISUP] grade group 2 and 3), patients were divided into two groups as PLND and no-PLND. More extensive PLND, defined as a number of removed nodes (NRN) ≥ 75th percentile.

RESULTS

After exclusion, a total of 631 patients were included: 351 (55.6%) had PLND and 280 (44.4%) had no-PLND. The mean age was 63.1 ± 3.60 years. The median NRN was 8.0 (1.0-40.0). The mean follow-up period was 47.7 ± 37.5 months. The lymph node involvement (LNI) rate was 5.7% in the overall cohort, 3.9% in ISUP grade 2, and 10.8% in ISUP grade 3. Patients with PLND were associated with more aggressive clinicopathologic characteristics but no significant difference in biochemical recurrence-free survival (BCRFS) was found between patients with PLND and no-PLND (p = 0.642). In the subgroup analysis for ISUP grades 2 and 3, no significant difference in BCRFS outcomes was found in patients with PLND and No-PLND (p = 0.680 and p = 0.922). Also, PLND extent had no effect on BCRFS (p = 0.569). The multivariable Cox regression model adjusted for preoperative tumor characteristics revealed that prostate specific antigen (PSA) (HR: 1.18, 95% CI: 1.01-1.25; p = 0.048) was an independent predictor of biochemical recurrence (BCR). The optimum cut-off value for PSA, which can predict BCRFS, was assigned to be 7.81 ng/ml, with an AUC of 0.63 (95% CI: 0.571-0.688). The highest sensitivity and specificity were 0.667 and 0.549.

CONCLUSION

Overall and cancer-specific survival analyzes were not evaluated because not enough events were observed. Neither PLND nor its extent improved BCRFS outcomes in IRPC. The LNI rate is low in patients with biopsy ISUP grade 2 and the BCR rate is low in those with PSA < 7.81 ng/dl so PLND can be omitted in these IRPC patients.

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.

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.

Identifying the Candidates Who Will Benefit From Extended Pelvic Lymph Node Dissection at Radical Prostatectomy Among Patients With Prostate Cancer

PURPOSE

The therapeutic effect of extended pelvic lymph node dissection (PLND) in prostate cancer (PCa) patients is still controversial. The aim of this study was to identify the PCa patients who may benefit from extended PLND based on the 2012 Briganti nomogram.

MATERIALS AND METHODS

PCa patients who underwent radical prostatectomy (RP) plus PLND between 2010 and 2015 were identified from the Surveillance, Epidemiology, and End Results (SEER) database. The probability of lymph node invasion (LNI), determined using the 2012 Briganti nomogram, was used to stratify the patients. The endpoints were overall survival (OS) and cancer-specific survival (CSS). Propensity score matching (PSM) was performed to account for potential differences between patients with and without extended PLND. Univariable and multivariable Cox regression was used to analyze the association between the number of removed nodes (NRN) and survival. Kaplan-Meier analysis was performed to estimate OS and CSS. Extended PLND was defined as NRN >75th percentile.

RESULTS

A total of 27,690 patients were included in the study. NRN was not an independent predictor of OS (p = 0.564). However, in patients with probability of LNI ≥37, multivariable analyses showed that increased NRN was associated with improved OS (hazard ratio [HR] = 0.963; p = 0.002). The 5-y OS rate was significantly higher for patients with NRN ≥12 than those with NRN <12 (94.9% vs. 91.9%, respectively; p = 0.015). In the PSM cohort, among patients with probability of LNI ≥37, multivariable analyses showed that increased NRN was associated with improved OS (HR = 0.961; p = 0.004). In addition, the 5-y OS rate was significantly higher for patients with NRN ≥12 than those with NRN <12 (94.9% vs. 89.8%, respectively; p = 0.002). However, NRN was not an independent predictor of CSS in any LNI risk subgroup (all p >0.05).

CONCLUSION

Extensive PLND might be associated with improved survival in PCa patients with a high risk of LNI, which supports the use of extended PLND in highly selected PCa patients. The results need to be validated in prospective studies with long-term follow-up.

Validating Modern NRG Oncology Pelvic Nodal and Groupe Francophone de Radiothérapie Urologique Prostate Bed Contouring Guidelines for Post-Prostatectomy Salvage Radiation: A Secondary Analysis of the LOCATE Trial

PURPOSE

We used the patterns of recurrence on ¹⁸F-fluciclovine positron emission tomography (PET)-computed tomography (CT) in patients enrolled in the LOCATE trial after prostatectomy to evaluate how well the most recent NRG Oncology and Groupe Francophone de Radiothérapie Urologique (GFRU) contouring recommendations encompassed all sites of recurrence in the prostate fossa and pelvic nodes in comparison to former Radiation Therapy Oncology Group (RTOG) recommendations.

METHODS AND MATERIALS

Patients with biochemically recurrent prostate cancer after radical prostatectomy with a positive finding within the prostate fossa or pelvic nodes on ¹⁸F-fluciclovine PET/CTs were identified from the LOCATE patient population. Areas of gross disease were delineated. Prostate fossa contours were delineated using both the 2010 RTOG consensus guidelines and the recently published 2020 GFRU consensus guidelines. Pelvic nodes were contoured with both the 2009 RTOG consensus guidelines and the 2020 NRG consensus guidelines. The performance of the contouring guidelines was assessed by determining what proportion of gross recurrent lesions were encompassed completely or marginally.

RESULTS

Of the 213 patients within the LOCATE trial, 45 patients were eligible for analysis with positive ¹⁸F-fluciclovine PET findings. Of the 30 total prostate fossa recurrences, the 2010 RTOG contour covered 20 (67%) and missed or marginally covered 10 (33%). The 2020 GFRU contour covered 27 recurrences (90%), and missed or marginally covered 3 (10%). Of the 43 total nodal recurrences, the 2009 RTOG pelvic nodal contour covered 29 nodes (67%), and missed or marginally covered 14 (32%). The 2020 NRG pelvic nodal contour covered 43 nodes (100%), with no misses or marginal coverage.

CONCLUSIONS

This secondary analysis of the LOCATE trial exemplifies the improved coverage of the latest prostate fossa contouring recommendations from the GFRU. Similarly, it also validates the updated 2020 NRG pelvic nodal contouring guidelines by demonstrating improved coverage of recurrent disease in this patient population.

Magnetometer-Guided Sentinel Lymph Node Dissection in Prostate Cancer: Rate of Lymph Node Involvement Compared with Radioisotope Marking

Simple Summary

Pelvic lymph node dissection is recommended in prostate cancer according to the patients’ individual risk for nodal metastases. Targeted removal of sentinel lymph nodes increases the number of detected lymph node metastases in patients with prostate cancer. We previously established magnetometer-guided sentinel lymph node dissection in patients with prostate cancer to overcome logistical and technical disadvantages associated with the standard radioisotope-guided technique. This retrospective study compared the magnetometer-guided and standard techniques in terms of their ability to detect lymph node metastases. Using the magnetometer-guided technique, more sentinel lymph nodes were detected per patient. The detected rates of lymph node involvement matched the predictions in both techniques equally well. Our findings confirm the reliability of magnetometer-guided sentinel lymph node dissection and highlight the importance of the sentinel technique for detecting lymph node metastases in prostate cancer.

Abstract

Sentinel pelvic lymph node dissection (sPLND) enables the targeted removal of lymph nodes (LNs) bearing the highest metastasis risk. In prostate cancer (PCa), sPLND alone or combined with extended PLND (ePLND) reveals more LN metastases along with detecting sentinel LNs (SLNs) outside the conventional ePLND template. To overcome the disadvantages of radioisotope-guided sPLND in PCa treatment, magnetometer-guided sPLND applying superparamagnetic iron oxide nanoparticles as a tracer was established. This retrospective study compared the nodal staging ability between magnetometer- and radioisotope-guided sPLNDs. We analyzed data of PCa patients undergoing radical prostatectomy and magnetometer- (848 patients, 2015–2021) or radioisotope-guided (2092 patients, 2006–2015) sPLND. To reduce heterogeneity among cohorts, we performed propensity score matching and compared data considering sentinel nomogram-based probabilities for LN involvement (LNI). Magnetometer- and radioisotope-guided sPLNDs had SLN detection rates of 98.12% and 98.09%, respectively; the former detected more SLNs per patient. The LNI rates matched nomogram-based predictions in both techniques equally well. Approximately 7% of LN metastases were detected outside the conventional ePLND template. Thus, we confirmed the reliability of magnetometer-guided sPLND in nodal staging, with results comparable with or better than radioisotope-guided sPLND. Our findings highlight the importance of the sentinel technique for detecting LN metastases in PCa.

Extended robot-assisted laparoscopic prostatectomy and extended pelvic lymph node dissection as a monotherapy in patients with very high-risk prostate cancer Patients

Background

Patients with very‐high‐risk prostate cancer (VHRPCa) have earlier biochemical recurrences (BCRs) and higher mortality rates. It remains unknown whether extended robot‐assisted laparoscopic prostatectomy (eRALP) without neoadjuvant or adjuvant therapy can improve the outcomes of VHRPCa patients. We aimed to determine the feasibility and efficacy of eRALP as a form of monotherapy for VHRPCa.

Methods

Data from 76 men who were treated with eRALP without neoadjuvant/adjuvant therapy were analyzed. eRALP was performed using an extrafascial approach. Extended pelvic lymph node (LN) dissection (ePLND) included nodes above the external iliac axis, in the obturator fossa, and around the internal iliac artery up to the ureter. The outcome measures were BCR, treatment failure (defined as when the prostate‐specific antigen level did not decrease to <0.1 ng/ml postoperatively), and urinary continence (UC). Kaplan–Meier, logistic regression, and Cox proportional‐hazards model were used to analyze the data.

Results

The median operative time was 246 min, and median blood loss was 50 ml. Twenty‐one patients experienced postoperative complications. Median follow‐up was 25.2 months; 19.7% of patients had treatment failure. Three‐year, BCR‐free survival rate was 62.0%. Castration‐resistant prostate cancer‐free survival rate was 86.1%. Overall survival was 100%. In 55 patients who had complete postoperative UC data, 47 patients (85.5%) recovered from their UC within 12 months. Clinical stage cT3b was an independent preoperative treatment failure predictor (p = 0.035), and node positivity was an independent BCR predictor (p = 0.037). The small sample size and retrospective nature limited the study.

Conclusions

This approach was safe and produced acceptable UC‐recovery rates. Preoperative seminal vesicle invasion is associated with treatment failure, and pathological LN metastases are associated with BCR. Therefore, our results may help informed decisions about neoadjuvant or adjuvant therapies in VHRPCa cases.

Precis

Extended robot‐assisted laparoscopic prostatectomy and extended pelvic lymph node dissection without adjuvant therapy is safe and effective for some patients with very‐high‐risk prostate cancer. The clinical stage and node positivity status predicted monotherapy failure, which may indicate good adjuvant therapy candidate.

A narrative review of fluorescence imaging in robotic-assisted surgery

Objective

In this review, we provide examples of applications of fluorescence imaging in urologic, gynecologic, general, and endocrine surgeries.

Background

While robotic-assisted surgery has helped increase the availability of minimally invasive procedures across surgical specialties, there remains an opportunity to reduce adverse events associated with open, laparoscopic, and robotic-assisted methods. In 2011, fluorescence imaging was introduced as an option to the da Vinci Surgical System, and has been standard equipment since 2014. Without interfering with surgical workflow, this fluorescence technology named Firefly^® allows for acquisition and display of near-infrared fluorescent signals that are co-registered with white light endoscopic images. As a result, robotic surgeons of all specialties have been able to explore the clinical utility of fluorescence guided surgery.

Methods

Literature searches were performed using the PubMed and MEDLINE databases using the keywords "robotic-assisted fluorescence surgery", "ICG robotic surgery", and "fluorescence guided surgery" covering the years 2011-2020.

Conclusions

Real-time intraoperative fluorescence guidance has shown great potential in helping guide surgeons in both simple and complex surgical interventions. Indocyanine green is one of the most widely-used imaging agents in fluorescence guided surgery, and other targeted, near-infrared imaging agents are in various stages of development. Fluorescence is becoming a reliable tool that can help surgeons in their decision-making process in some specialties, while explorations continue in others.

On the probability of lymph node negativity in pN0-staged prostate cancer-a theoretically derived rule of thumb for adjuvant needs

Purpose

The extent of lymphadenectomy and clinical features influence the risk of occult nodes in node-negative prostate cancer. We derived a simple estimation model for the negative predictive value (npv) of histopathologically node-negative prostate cancer patients (pN0) to guide adjuvant treatment.

Methods

Approximations of sensitivities in detecting lymph node metastasis from current publications depending on the number of removed lymph nodes were used for a theoretical deduction of a simplified formulation of npv assuming a false node positivity of 0.

Results

A theoretical formula of npv = p(N0IpN0) = (100 − prevalence) / (100 − sensitivity × prevalence) was calculated (sensitivity and preoperative prevalence in %). Depending on the number of removed lymph nodes (nLN), the sensitivity of pN0-staged prostate cancer was derived for three sensitivity levels accordingly: sensitivity = f(nLN) = 9 × nLN /100 for 0 ≤ nLN ≤ 8 and f(nLN) = (nLN + 70) /100 for 9 ≤ nLN ≤ 29 and f(nLN) = 1 for nLN ≥ 30.

Conclusion

We developed a theoretical formula for estimation of the npv in pN0-staged prostate cancer patients. It is a sine qua non to use the formula in a clinically experienced context before deciding to electively irradiate pelvic lymph nodes or to intensify adjuvant systemic treatment.

Head-to-Head Comparison of 68Ga-Prostate-Specific Membrane Antigen PET/CT and Ferumoxtran-10-Enhanced MRI for the Diagnosis of Lymph Node Metastases in Prostate Cancer Patients

Accurate assessment of lymph node (LN) metastases in prostate cancer (PCa) patients is critical for prognosis and patient management. Both prostate-specific membrane antigen (PSMA) PET/CT and ferumoxtran-10 nanoparticle-enhanced MRI (nano-MRI) are imaging modalities with high potential to identify LN metastases in PCa patients. The aim of this study was to compare the results of these imaging technologies in terms of characteristics and anatomic localization of suspicious LNs in order to assess the feasibility of their complementary use for imaging in PCa patients. Methods: In total, 45 patients with either primary PCa (n = 8) or recurrence (n = 36) were included in this retrospective study. All patients underwent both 68Ga-PSMA PET/CT and nano-MRI between October 2015 and July 2017 within 3 wk. Both scans were performed at the same institution according to local clinical protocols. All scans were analyzed independently by experienced nuclear medicine physicians and radiologists. The size, anatomic location, and level of suspicion were determined for all visible LNs. Subsequently, the findings from 68Ga-PSMA PET/CT and nano-MRI were compared without respect to a reference standard. Results: In total, 179 suspicious LNs were identified. Significantly more suspicious LNs per patient were detected by nano-MRI (P < 0.001): 160 were identified in 33 patients by nano-MRI, versus 71 in 25 patients by 68Ga-PSMA PET/CT. Of all suspicious LNs, 108 were identified only by nano-MRI (60%), 19 (11%) only by 68Ga-PSMA PET/CT, and 52 (29%) by both methods. The mean size of the suspicious LNs as identified by nano-MRI was significantly smaller (5.3 mm) than that by 68Ga-PSMA PET/CT (6.0 mm; P = 0.006). The median level of suspicion did not differ significantly. Both modalities identified suspicious LNs in all anatomic regions of the pelvis. Conclusion: Both modalities identified suspicious LNs that were missed by the other. Both modalities identified suspicious LNs in all anatomic regions of the pelvis; however, nano-MRI appeared to be superior in detecting smaller suspicious LNs. These findings suggest that nano-MRI has a potential role as a complement to PSMA PET/CT. However, since the clinical implications of the different results are not well established yet, further investigation of this complementary use is encouraged.

Implementation of radioguided surgery in prostate cancer

With the development of new imaging technologies and tracers, the applications of radioguided surgery for prostate cancer are growing rapidly. The current paper aims to give an overview of the recent advances of radioguided surgery in the management of prostate cancer. We performed a literature search to give an overview of the current status of radioguided surgery for prostate cancer. Three modalities of radioguided surgery, the sentinel node procedure, Cerenkov Luminescence / beta-radio-guided surgery and radio-guided salvage surgery in recurrent prostate cancer, were reviewed in detail. Radioguided surgery for prostate cancer has shown promising value in the treatment of primary diagnosed prostate cancer and recurrent loco-regional lymph node positive prostate cancer. Advances have been made into minimal invasive (robot-assisted) laparoscopic surgery. The sentinel node procedure for prostate cancer has been further developed and is currently performed with high diagnostic sensitivity. Cerenkov luminescence imaging is a feasible and encouraging technique for intraoperative margin assessment in prostate cancer. Radioguided surgery in recurrent prostate cancer has shown to be feasible, yielding high sensitivity and specificity for detecting small local recurrences and metastases. With the availability of different new tracers, the road has been paved towards clinically feasible radioguided surgery for prostate cancer. Novel technologies now being developed for minimal invasive surgery are speeding up clinical research. Currently, none of the radioguided surgery techniques mentioned have been accepted as standard of care.

Therapeutic Consequences of Omitting a Pelvic Lymph Node Dissection at Radical Prostatectomy when Grade and/or Stage Increase

OBJECTIVE

To analyze the effect on biochemical recurrence (BCR) of omitting PLND in subsequently upgraded/upstaged patients (pNx regret). Using nomograms, patients with low to intermediate-risk prostate cancer can be selected to omit a pelvic lymph node dissection (PLND) at the time of a radical prostatectomy (RP). However, some patients will experience upgraded pathology and/or stage.

MATERIALS AND METHODS

We searched a prospectively maintained single institution/multi-surgeon cohort of patients treated by RP and >5-year follow-up. From 2006-2012, 1026 (521 pNx and 505 pN0/1) eligible patients with biopsy Gleason Score ≤3+4 and cT1c-cT2 undergoing RARP were included in the study.

RESULTS

Gleason upgrading from ≤3+4 to >3+4 and/or pT3-4 occurred in 17% of pNx and 32% of pN0/N1 (p<0.001). BCR occurred in 5% of the pNx, and 7% of the PLND group. Five-year BCR free survival was higher in the pNx group (94.7% vs. 91%, P = .048). BCR occurred in 3% in the non-pNx regret and 18% in the pNx regret patients. However, with propensity score matching with pNx regret and pN0/N1 patients, 5-year BCR free survival rates were similar (81% vs 77%, P = .466).

CONCLUSIONS

Low to favorable intermediate-risk patients who PLND was omitted and experienced upgrading or upstaging (pNx regret), have a higher predicted BCR. However, when matched to a similar cohort with pN0/N1, the BCR did not differ. Omission of a PLND does not appear to alter the rates of BCR compared to PLND inclusion.

The Distribution of Pelvic Nodal Metastases in Prostate Cancer Reveals Potential to Advance and Personalize Pelvic Radiotherapy

Background

Traditional clinical target volume (CTV) definition for pelvic radiotherapy in prostate cancer consists of large volumes being treated with homogeneous doses without fully utilizing information on the probability of microscopic involvement to guide target volume design and prescription dose distribution.

Methods

We analyzed patterns of nodal involvement in 75 patients that received RT for pelvic and paraaortic lymph node metastases (LNs) from prostate cancer in regard to the new NRG-CTV recommendation. Non-rigid registration-based LN mapping and weighted three-dimensional kernel density estimation were used to visualize the average probability distribution for nodal metastases. As independent approach, the mean relative proportion of LNs observed for each level was determined manually and NRG and non-NRG levels were evaluated for frequency of involvement. Computer-automated distance measurements were used to compare LN distances in individual patients to the spatial proximity of nodal metastases at a cohort level.

Results

34.7% of patients had pelvic LNs outside NRG-consensus, of which perirectal was most common (25.3% of all patients) followed by left common iliac nodes near the left psoas major (6.7%). A substantial portion of patients (13.3%) had nodes at the posterior edge of the NRG obturator level. Observer-independent mapping consistently visualized high-probability hotspots outside NRG-consensus in the perirectal and left common iliac regions. Affected nodes in individual patients occurred in highly significantly closer proximity than at cohort-level (mean distance, 6.6 cm vs. 8.7 cm, p < 0.001).

Conclusions

Based on this analysis, the common iliac level should extend to the left psoas major and obturator levels should extend posteriorly 5 mm beyond the obturator internus. Incomplete coverage by the NRG-consensus was mostly because of perirectal involvement. We introduce three-dimensional kernel density estimation after non-rigid registration-based mapping for the analysis of recurrence data in radiotherapy. This technique provides an estimate of the underlying probability distribution of nodal involvement and may help in addressing institution- or subgroup-specific differences. Nodal metastases in individual patients occurred in highly significantly closer proximity than at a cohort-level, which supports that personalized target volumes could be reduced in size compared to a “one-size-fits-all” approach and is an important basis for further investigation into individualized field designs.

The Role of Magnetic Resonance Imaging in (Future) Cancer Staging: Note the Nodes

The presence or absence of lymph node metastases is a very important prognostic factor in patients with solid tumors. Current invasive and noninvasive diagnostic methods for N-staging like lymph node dissection, morphologic computed tomography/magnetic resonance imaging (MRI), or positron emission tomography-computed tomography have significant limitations because of technical, biological, or anatomical reasons. Therefore, there is a great clinical need for more precise, reliable, and noninvasive N-staging in patients with solid tumors. Using ultrasmall superparamagnetic particles of ironoxide (USPIO)-enhanced MRI offers noninvasive diagnostic possibilities for N-staging of different types of cancer, including the 4 examples given in this work (head and neck cancer, esophageal cancer, rectal cancer, and prostate cancer). The excellent soft tissue contrast of MRI and an USPIO-based differentiation of metastatic versus nonmetastatic lymph nodes can enable more precise therapy and, therefore, fewer side effects, essentially in cancer patients in oligometastatic disease stage. By discussing 3 important questions in this article, we explain why lymph node staging is so important, why the timing for more accurate N-staging is right, and how it can be done with MRI. We illustrate this with the newest developments in magnetic resonance methodology enabling the use of USPIO-enhanced MRI at ultrahigh magnetic field strength and in moving parts of the body like upper abdomen or mediastinum. For prostate cancer, a comparison with radionuclide tracers connected to prostate specific membrane antigen is made. Under consideration also is the use of MRI for improvement of ex vivo cancer diagnostics. Further scientific and clinical development is needed to assess the accuracy of USPIO-enhanced MRI of detecting small metastatic deposits for different cancer types in different anatomical locations and to broaden the indications for the use of (USPIO-enhanced) MRI in lymph node imaging in clinical practice.

A DROP-IN Gamma Probe for Robot-assisted Radioguided Surgery of Lymph Nodes During Radical Prostatectomy

BACKGROUND

The DROP-IN gamma probe was introduced to overcome the restricted manoeuvrability of traditional laparoscopic gamma probes. Through enhanced manoeuvrability and surgical autonomy, the DROP-IN promotes the implementation of radioguided surgery in the robotic setting.

OBJECTIVE

To confirm the utility and safety profile of the DROP-IN gamma probe and to perform a comparison with the traditional laparoscopic gamma probe and fluorescence guidance.

DESIGN, SETTING, AND PARTICIPANTS

Twenty-five prostate cancer patients were scheduled for a robot-assisted sentinel lymph node (SN) procedure, extended pelvic lymph node dissection, and prostatectomy at a single European centre.

SURGICAL PROCEDURE

After intraprostatic injection of indocyanine green (ICG)-^99mTc-nanocolloid (n = 12) or ^99mTc-nanocolloid + ICG (n = 13), SN locations were defined using preoperative imaging. Surgical excision of SNs was performed under image guidance using the DROP-IN gamma probe, the traditional laparoscopic gamma probe, and fluorescence imaging.

MEASUREMENTS

Intraoperative SN detection was assessed for the different modalities and related to anatomical locations. Patient follow-up was included (a median of 18 mo).

RESULTS AND LIMITATIONS

Overall, 47 SNs were pursued in vivo by the DROP-IN gamma probe, of which 100% were identified. No adverse events related to its use were observed. In vivo fluorescence imaging identified 91% of these SNs. The laparoscopic gamma probe identified only 76% of these SNs, where the detection inaccuracies appeared to be related to specific anatomical regions.

CONCLUSIONS

Owing to improved manoeuvrability, the DROP-IN probe yielded improved SN detection rates compared with the traditional gamma probe and fluorescence imaging. These findings underline that the DROP-IN technology provides a valuable tool for radioguided surgery in the robotic setting.

PATIENT SUMMARY

Radioguided robot-assisted surgery with the novel DROP-IN gamma probe is feasible and safe. It enables more efficient intraoperative identification of sentinel lymph nodes than can be achieved with a traditional laparoscopic gamma probe. The use of the DROP-IN probe in combination with fluorescence imaging allows for a complementary optical confirmation of node localisations.

Surgical management of high-risk, localized prostate cancer

High-risk prostate cancer is a heterogeneous disease that lacks clear consensus on its ideal management. Historically, non-surgical treatment was the preferred strategy, and several studies demonstrated improved survival among men with high-risk disease managed with the combination of radiotherapy and androgen deprivation therapy (ADT) compared with ADT alone. However, practice trends in the past 10-15 years have shown increased use of radical prostatectomy with pelvic lymph node dissection for primary management of high-risk, localized disease. Radical prostatectomy, as a primary monotherapy, offers the potential benefits of avoiding ADT, reducing rates of symptomatic local recurrence, enabling full pathological tumour staging and potentially reducing late adverse effects such as secondary malignancy compared with radiation therapy. Retrospective studies have reported wide variability in short-term (pathological) and long-term (oncological) outcomes of radical prostatectomy. Surgical monotherapy continues to be appropriate for selected patients, whereas in others the best treatment strategy probably involves a multimodal approach. Appropriate risk stratification utilizing clinical, pathological and potentially also genomic risk data is imperative in the initial management of men with prostate cancer. However, data from ongoing and planned prospective trials are needed to identify the optimal management strategy for men with high-risk, localized prostate cancer.

Patterns of Lymph Node Failure in Patients With Recurrent Prostate Cancer Postradical Prostatectomy and Implications for Salvage Therapies

PURPOSE

There is increasing use of radical prostatectomy to treat patients with high-risk prostate cancer. This has contributed toward a pathologic stage migration, and a greater number of patients are subsequently being diagnosed with biochemical failure. There is increasing use of advanced imaging techniques in the setting of biochemical failure, including positron emission tomography-computed tomography (PET-CT).

METHODS AND MATERIALS

This critical literature review highlights the evidence for PET-CT in postprostatectomy biochemical failure and identifies sites of pelvic lymph node relapse in the setting of biochemical failure and the potential implications that the locations of these relapses may have for salvage therapies. Potential future directions are then considered.

RESULTS

The optimal PET-CT tracer remains uncertain but there is increasing use of prostate-specific membrane antigen PET-CT for investigating sites of nodal metastasis at low prostate-specific antigen levels, and this is leading to a blurring of the biochemical and radiologic recurrence phases. The optimal therapeutic approach remains undefined, with current trials investigating postoperative radiation therapy to the whole pelvis in addition to the prostatic fossa, the use of PET-CT in the setting of biochemical recurrence to guide delivery of salvage radiation therapy, and, for patients with node-only relapsed prostate cancer, the addition of whole pelvis radiation therapy to metastasis-directed therapies such as stereotactic ablative radiotherapy.

CONCLUSIONS

The most appropriate target volume for salvage radiation therapy remains uncertain, and the findings of studies using PET-CT to map nodal recurrences suggest that there could be a role for extending whole pelvis radiation therapy volumes to increase coverage of superior nodal regions. The emerging fields of radiomics and radiogenomics could provide important prognostic information and aid decision making for patients with relapsed prostate cancer.

Role of metabolic imaging in diagnosis of primary, metastatic, and recurrent prostate cancer

PURPOSE OF REVIEW

The present review describes the current role of metabolic imaging techniques such as multiparametric MRI (mpMRI), magnetic resonance spectroscopic imaging (MRSI), hyperpolarized MRSI, and positron emission tomography (PET) in the diagnosis of primary prostate cancer, surveillance of low-grade disease, detection of metastases, and evaluation of biochemical recurrence after therapy.

RECENT FINDINGS

The natural history of prostate cancer ranges from indolent disease that is optimally monitored by active surveillance, to highly aggressive disease that can be lethal. Current diagnostic methods remain imperfect in noninvasively distinguishing between silent versus aggressive tumors. Hence, there is a high demand for noninvasive imaging techniques that offer insight into biological behavior of prostate cancer cells. Characterization of prostate cancer metabolism is a promising area to provide such insights.

SUMMARY

Metabolic imaging may allow for greater detection and ultimately characterization of tumor based on aggressiveness and spread. Hence, it has the potential to monitor tumor activity, predict prognostic outcomes, and guide individualized therapies.

Magnetic resonance imaging at ultra-high magnetic field strength: An in vivo assessment of number, size and distribution of pelvic lymph nodes

Objective

The definition of an in vivo nodal anatomical baseline is crucial for validation of representative lymph node dissections and accompanying pathology reports of pelvic cancers, as well as for assessing a potential therapeutic effect of extended lymph node dissections. Therefore the number, size and distribution of lymph nodes in the pelvis were assessed with high-resolution, large field-of-view, 7 Tesla (T) magnetic resonance imaging (MRI) with frequency-selective excitation.

Materials and methods

We used 7 T MRI for homogeneous pelvic imaging in 11 young healthy volunteers. Frequency-selective imaging of water and lipids was performed to detect nodal structures in the pelvis. Number and size of detected nodes was measured and size distribution per region was assessed. An average volunteer-normalized nodal size distribution was determined.

Results

In total, 564 lymph nodes were detected in six pelvic regions. Mean number was 51.3 with a wide range of 19–91 lymph nodes per volunteer. Mean diameter was 2.3 mm with a range of 1 to 7 mm. 69% Was 2 mm or smaller. The overall size distribution was very similar to the average volunteer-normalized nodal size distribution.

Conclusions

The amount of in vivo visible lymph nodes varies largely between subjects, whereas the normalized size distribution of nodes does not. The presence of many small lymph nodes (≤2mm) renders representative or complete removal of pelvic lymph nodes to be very difficult. 7T MRI may shift the in vivo detection limits of lymph node metastases in the future.

Pelvic lymph node distribution and metastases of prostate and bladder cancer: a systematic literature review and template proposal

PURPOSE

To systematically review the relevant literature that evaluates the LN topographical distribution and propose a uniform template.

METHODS

A bibliographic search of PubMed/Medline, Embase and SCOPUS was performed for studies reporting data of LN imaging and/or nodal resection.

RESULTS

101 and 26 articles met the inclusion criteria for PCa and BCa, respectively. In PCa, the most common locations of positive LNs for surgical and imaging studies were external iliac (both 38 studies), followed by obturator (38 and 37, respectively). Similarly, in BCa, the most common location of positive nodes for surgical and imaging studies were external iliac (19 and 4, respectively), followed by obturator (15 and 3 studies, respectively). In PCa, median percentages of positive external iliac nodes/patient were 12.2% and 11.6% for surgical and imaging studies, respectively while corresponding rates for BCa were 3.9% and 17.6%. There were high risks of bias across studies as well as high heterogeneity in the definition of the anatomic boundaries of lymphadenectomy templates.

CONCLUSIONS

This review highlights the lack of detailed information on exact LN templates and metastases location, which in turn hinders generation of high-quality evidence on optimal lymphadenectomy templates. Our proposed template is applicable for both imaging and surgical description and could facilitate the translation of anatomical location from imaging to surgical resection.