Validation of sentinel lymph node dissection in prostate cancer: experience in more than 2,000 patients

Non-Invasive Detection, Precise Localization, and Perioperative Navigation of In Vivo Deep Lesions Using Transmission Raman Spectroscopy

Non-invasive detection and precise localization of deep lesions have attracted significant attention for both fundamental and clinical studies. Optical modality techniques are promising with high sensitivity and molecular specificity, but are limited by shallow tissue penetration and the failure to accurately determine lesion depth. Here the authors report in vivo ratiometric surface-enhanced transmission Raman spectroscopy (SETRS) for non-invasive localization and perioperative surgery navigation of deep sentinel lymph nodes in live rats. The SETRS system uses ultrabright surface-enhanced Raman spectroscopy (SERS) nanoparticles with a low detection limit of 10 pM and a home-built photosafe transmission Raman spectroscopy setup. The ratiometric SETRS strategy is proposed based on the ratio of multiple Raman spectral peaks for obtaining lesion depth. Via this strategy, the depth of the phantom lesions in ex vivo rat tissues is precisely determined with a mean-absolute-percentage-error of 11.8%, and the accurate localization of a 6-mm-deep rat popliteal lymph node is achieved. The feasibility of ratiometric SETRS allows the successful perioperative navigation of in vivo lymph node biopsy surgery in live rats under clinically safe laser irradiance. This study represents a significant step toward the clinical translation of TRS techniques, providing new insights for the design and implementation of in vivo SERS applications.

A hybrid radioactive and fluorescence approach is more than the sum of its parts; outcome of a phase II randomized sentinel node trial in prostate cancer patients

OBJECTIVE

To determine the diagnostic accuracy of the hybrid tracer indocyanine green (ICG)-Technetium-99 m(99mTc)-nanocolloid compared to sequential tracers of 99mTc-nanocolloid and free-ICG in detecting tumor-positive lymph nodes (LN) during primary surgery in prostate cancer (PCa) patients.

INTRODUCTION

Image-guided surgery strategies can help visualize individual lymphatic drainage patterns and sentinel lymph nodes (SLNs) in PCa patients. For lymphatic mapping radioactive, fluorescent and hybrid tracers are being clinically exploited. In this prospective randomized phase II trial, we made a head-to-head comparison between ICG-99mTc-nanocolloid (hybrid group) and 99mTc-nanocolloid and subsequent free-ICG injection (sequential group).

METHODS

PCa patients with a  >5% risk of lymphatic involvement according to the 2012 Briganti nomogram and planned for prostatectomy were included and randomized (1:1) between ultrasound-guided intraprostatic tracer administration of ICG-99mTc-nanocolloid (n = 69) or 99mTc-nanocolloid (n = 69) 5 h before surgery. Preoperative lymphoscintigraphy and SPECT/CT were performed to define the locations of the SLNs. Additionally, all participants in the sequential group received an injection of free-ICG at time of surgery. Subsequently, all (S)LNs were dissected using fluorescence guidance followed by an extended pelvic lymph node dissection (ePLND). The primary outcome was the total number of surgically removed (S)LNs and tumor-positive (S)LNs.

RESULTS

The total number of surgically removed (S)LN packages was 701 and 733 in the hybrid and sequential groups, respectively (p = 0.727). The total number of fluorescent LNs retrieved was 310 and 665 nodes in the hybrid and sequential groups, respectively (p < 0.001). However, no statistically significant difference was observed in the corresponding number of tumor-positive nodes among the groups (44 vs. 33; p = 0.470). Consequently, the rate of tumor-positive fluorescent LNs was higher in the hybrid group (7.4%) compared to the sequential group (2.6%; p = 0.002), indicating an enhanced positive predictive value for the hybrid approach. There was no difference in complications within 90 days after surgery (p = 0.78).

CONCLUSIONS

The hybrid tracer ICG-99mTc-nanocolloid improved the positive predictive value for tumor-bearing LNs while minimizing the number of fluorescent nodes compared to the sequential tracer approach. Consequently, the hybrid tracer ICG-99mTc-nanocolloid enables the most reliable and minimal invasive method for LN staging in PCa patients.

Influence of lymph node degeneration on metastases in prostate cancer: or why we must look for a needle in a haystack

BACKGROUND

To evaluate the incidence of lymph node degeneration and its association with nodal metastatic pattern in prostate cancer.

METHODS

A retrospective analysis of the submitted lymph node specimen of 390 prostatectomies in 2011 was performed. All lymph nodes were histologically re-evaluated and the degree of lymph node degeneration e.g. lipomatous atrophy, capsular and framework fibrosis, and calcifications as well as the lymph node size were recorded. Lymph node degeneration was compared in the anatomic regions of the pelvis as well as in lymph nodes with and without metastases of prostatic cancer.

RESULTS

Eighty-one of 6026 lymph nodes demonstrated metastases. Complete histologic examination with analysis of a complete cross-section was possible in 5173 lymph nodes including all lymph nodes with metastases. The incidence of lymph node degeneration was different across the various landing sites. Lymph node metastases were primarily detected in less degenerative and therefore more functional lymph nodes. In metastatic versus non-metastatic lymph nodes low lipomatous atrophy was reported in 84.0% versus 66.7% (p = 0.004), capsular fibrosis in 14.8% versus 35.4% (p < 0.001), calcifications in 35.8% versus 46.1% (p = 0.072) and framework fibrosis in 69.8% versus 75.3% (p = 0.53). Metastases were also identified more frequently in larger than in smaller lymph nodes (63.0% vs. 47.5%; p = 0.007).

CONCLUSIONS

Degenerative changes in pelvic lymph nodes are commonly detectable but occur with variable frequency in the various nodal landing sites in the pelvis. The degree of lymph node degeneration of single lymph nodes has a significant influence on whether a lymph node is infiltrated by tumor cells and may harbour metastases.

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.

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.

Prostatic urethra recurrence after transurethral resection of bladder tumor (TURBT) for non-muscle-invasive bladder cancer (NMIBC)

Urinary bladder cancer is frequently multifocal and has a high incidence of recurrence. Although the prostatic urethra is a frequent site of tumor relapse in patients with non-muscle-invasive bladder cancer treated with TURBT, such tumors are often underdiagnosed. Here we present two cases having urethral recurrence after TURBT.

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.

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.

Molecular Imaging in Primary Staging of Prostate Cancer Patients: Current Aspects and Future Trends

Accurate primary staging is the cornerstone in all malignancies. Different morphological imaging modalities are employed in the evaluation of prostate cancer (PCa). Regardless of all developments in imaging, invasive histopathologic evaluation is still the standard method for the detection and staging of the primary PCa. Magnetic resonance imaging (MRI) and computed tomography (CT) play crucial roles; however, functional imaging provides additional valuable information, and it is gaining ever-growing acceptance in the management of PCa. Targeted imaging with different radiotracers has remarkably evolved in the past two decades. [111In]In-capromab pendetide scintigraphy was a new approach in the management of PCa. Afterwards, positron emission tomography (PET) tracers such as [11C/18F]choline and [11C]acetate were developed. Nevertheless, none found a role in the primary staging. By introduction of the highly sensitive small molecule prostate-specific membrane antigen (PSMA) PET/CT, as well as recent developments in MRI and hybrid PET/MRI systems, non-invasive staging of PCa is being contemplated. Several studies investigated the role of these sophisticated modalities in the primary staging of PCa, showing promising results. Here, we recapitulate the role of targeted functional imaging. We briefly mention the most popular radiotracers, their diagnostic accuracy in the primary staging of PCa, and impact on patient management.

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.

Radioactive polymeric nanoparticles for biomedical application

Nowadays, emerging radiolabeled nanosystems are revolutionizing medicine in terms of diagnostics, treatment, and theranostics. These radionuclides include polymeric nanoparticles (NPs), liposomal carriers, dendrimers, magnetic iron oxide NPs, silica NPs, carbon nanotubes, and inorganic metal-based nanoformulations. Between these nano-platforms, polymeric NPs have gained attention in the biomedical field due to their excellent properties, such as their surface to mass ratio, quantum properties, biodegradability, low toxicity, and ability to absorb and carry other molecules. In addition, NPs are capable of carrying high payloads of radionuclides which can be used for diagnostic, treatment, and theranostics depending on the radioactive material linked. The radiolabeling process of nanoparticles can be performed by direct or indirect labeling process. In both cases, the most appropriate must be selected in order to keep the targeting properties as preserved as possible. In addition, radionuclide therapy has the advantage of delivering a highly concentrated absorbed dose to the targeted tissue while sparing the surrounding healthy tissues. Said another way, radioactive polymeric NPs represent a promising prospect in the treatment and diagnostics of cardiovascular diseases such as cardiac ischemia, infectious diseases such as tuberculosis, and other type of cancer cells or tumors.

Contemporary update of SPECT tracers and novelties in radioguided surgery: a perspective based on urology

Recent technical advances and implementation of novel radiotracers have further increased the potential of radioguided surgery for a broad variety of malignancies. Indeed, the possibilities for future applications of novel radiotracers in diverse oncological strategies has become more promising than ever. This literature review aims to provide a contemporary update on a selected group of radiotracers and evaluates the usability of radioguided surgery and sentinel node procedures, focusing on most promising advances. For example, the impact of targeted radiotracers on prostate specific membrane antigen (PSMA), CD206 receptor-targeted agents (^99mTc-tilmanocept), and hybrid tracers adding fluorescence to radioguidance (ICG-^99mTc-nanocolloid) as well as targeting hypoxia-induced carbonic anhydrase IX (CAIX) will be covered. Furthermore, future outlooks on the implementation of gold nanoparticles (AuNP's), but also technical advances in improved radiotracer detection by hybrid gamma devices will be discussed.

Haute Couture or Ready-to-Wear? Tailored Pelvic Radiotherapy for Prostate Cancer Based on Individualized Sentinel Lymph Node Detection

Prostate cancer (PCa) pelvic radiotherapy fields are defined by guidelines that do not consider individual variations in lymphatic drainage. We examined the feasibility of personalized sentinel lymph node (SLN)-based pelvic irradiation in PCa. Among a SLN study of 202 patients, we retrospectively selected 57 patients with a high risk of lymph node involvement. Each single SLN clinical target volume (CTV) was individually segmented and pelvic CTVs were contoured according to Radiation Therapy Oncology Group (RTOG) guidelines. We simulated a radiotherapy plan delivering 46 Gy and calculated the dose received by each SLN. Among a total of 332 abdominal SLNs, 305 pelvic SLNs (beyond the aortic bifurcation) were contoured (mean 5.4/patient). Based on standard guidelines, CTV missed 67 SLNs (22%), mostly at the common iliac level (40 SLNs). The mean distance between iliac vessels and the SLN was 11mm, and despite a 15mm margin around the iliac vessels, 9% of SLNs were not encompassed by the CTV. Moreover, 42 SLNs (63%) did not receive 95% of the prescribed dose. Despite a consensus on contouring guidelines, a significant proportion of SLNs were not included in the pelvic CTV and did not receive the prescribed dose. A tailored approach based on individual SLN detection would avoid underdosing pelvic lymph nodes that potentially contain tumor cells.

Accuracy of Magnetometer-Guided Sentinel Lymphadenectomy after Intraprostatic Injection of Superparamagnetic Iron Oxide Nanoparticles in Prostate Cancer: The SentiMag Pro II Study

Radioisotope-guided sentinel lymph node dissection (sLND) has shown high diagnostic reliability in prostate (PCa) and other cancers. To overcome the limitations of the radioactive tracers, magnetometer-guided sLND using superparamagnetic iron oxide nanoparticles (SPIONs) has been successfully used in PCa. This prospective study (SentiMag Pro II, DRKS00007671) determined the diagnostic accuracy of magnetometer-guided sLND in intermediate- and high-risk PCa. Fifty intermediate- or high-risk PCa patients (prostate-specific antigen (PSA) ≥ 10 ng/mL and/or Gleason score ≥ 7; median PSA 10.8 ng/mL, IQR 7.4–19.2 ng/mL) were enrolled. After the intraprostatic SPIONs injection a day earlier, patients underwent magnetometer-guided sLND and extended lymph node dissection (eLND, followed by radical prostatectomy. SLNs were detected in in vivo and in ex vivo samples. Diagnostic accuracy of sLND was assessed using eLND as the reference. SLNs were detected in all patients (detection rate 100%), with 447 sentinel lymph nodes SLNs (median 9, IQR 6–12) being identified and 966 LNs (median 18, IQR 15–23) being removed. Thirty-six percent (18/50) of patients had LN metastases (median 2, IQR 1–3). Magnetometer-guided sLND had 100% sensitivity, 97.0% specificity, 94.4% positive predictive value, 100% negative predictive value, 0.0% false negative rate, and 3.0% additional diagnostic value (LN metastases only in SLNs outside the eLND template). In vivo, one positive SLN/LN-positive patient was missed, resulting in a sensitivity of 94.4%. In conclusion, this new magnetic sentinel procedure has high accuracy for nodal staging in intermediate- and high-risk PCa. The reliability of intraoperative SLN detection using this magnetometer system requires verification in further multicentric studies.

Diagnostic Accuracy of Magnetometer-Guided Sentinel Lymphadenectomy After Intraprostatic Injection of Superparamagnetic Iron Oxide Nanoparticles in Intermediate- and High-Risk Prostate Cancer Using the Magnetic Activity of Sentinel Nodes

Due to the high morbidity of extended lymph node dissection (eLND) and the low detection rate of limited lymph node dissection (LND), targeted sentinel lymph node dissection (sLND) was implemented in prostate cancer (PCa). Subsequently, nonradioactive sentinel lymph node (SLN) detection using magnetic resonance imaging (MRI) and a magnetometer after intraprostatic injection of superparamagnetic iron oxide nanoparticles (SPIONs) was successfully applied in PCa. To validate the reliability of this approach, considering the magnetic activity of SLNs or whether it is sufficient to dissect only the most active SLNs as shown in other tumor entities for radio-guided sLND, we analyzed magnetometer-guided sLND results in 218 high- and intermediate-risk PCa patients undergoing eLND as a reference standard. Using a sentinel nomogram to predict lymph node invasion (LNI), a risk range was determined up to which LND could be dispensed with or sLND only would be adequate. In total, 3,711 LNs were dissected, and 1,779 SLNs (median, 8) were identified. Among 78 LN-positive patients, there were 264 LN metastases (median, 2). sLND had a 96.79% diagnostic rate, 88.16% sensitivity, 98.59% specificity, 97.1% positive predictive value (PPV), 93.96% negative predictive value (NPV), 4.13% false-negative rate, and 0.92% additional diagnostic value (LN metastases only outside the eLND template). For intermediate-risk patients only, the sensitivity, specificity, PPV, and NPV were 100%. Magnetic activities of SLNs were heterogeneous regardless of metastasis. The accuracy of predicting the presence of metastases for each LN from the proportion of activity was only 57.3% in high- and 65% in intermediate-risk patients. Patients with LNI risk of less than 5% could have been spared LND, as no positive LNs were found in this group. For patients with an LNI risk between 5% and 20%, sLND-only would have been sufficient to detect almost all LN metastases; thus, eLND could be dispensed with in 36% of patients. In conclusion, SPION-guided sLND is a reliable alternative to eLND in intermediate-/high-risk PCa. No conclusions can be drawn from magnetic SLN activity regarding the presence of metastases. LND could be dispensed with according to a nomogram of predicted probability for LNI of 5% without losing any LN-positive patient. Patients with LNI risk between 5% and 20% could be spared eLND by performing sLND.

PSMA-targeting agents for radio- and fluorescence-guided prostate cancer surgery

Despite recent improvements in imaging and therapy, prostate cancer (PCa) still causes substantial morbidity and mortality. In surgical treatment, incomplete resection of PCa and understaging of possible undetected metastases may lead to disease recurrence and consequently poor patient outcome. To increase the chance of accurate staging and subsequently complete removal of all cancerous tissue, prostate specific membrane antigen (PSMA) targeting agents may provide the surgeon an aid for the intraoperative detection and resection of PCa lesions. Two modalities suitable for this purpose are radionuclide detection, which allows sensitive intraoperative localization of tumor lesions with a gamma probe, and fluorescence imaging, allowing tumor visualization and delineation. Next to fluorescence, use of photosensitizers may enable intraoperative targeted photodynamic therapy to eradicate remaining tumor lesions. Since radiodetection and optical imaging techniques each have their own strengths and weaknesses, a combination of both modalities could be of additional value. Here, we provide an overview of recent preclinical and clinical advances in PSMA-targeted radio- and fluorescence-guided surgery of PCa.

Current Imaging Techniques for Lymph Node Staging in Prostate Cancer: A Review

Introduction: Lymph node metastases (LNM) represent a proven prognostic factor for biochemical recurrence (BCR)-free survival, metastatic free survival and overall survival in prostate cancer (PCa). Although pelvic node dissection remains the gold standard for the detection of LNM, novel imaging techniques are entering clinical practice, in the effort to improve LNM detection and spare unnecessary surgeries. Aim of the current review is to describe such imaging techniques and explore their advantages and limitations.

Evidence Acquisition: The National Library of Medicine Database was searched for relevant articles published between January 2013 and August 2018. A wide search was performed including the combination of following words: “Prostate” and “Cancer” and “staging” and “Lymph Node” and “imaging” and (“MRI” or “PET”). The initial list of selected papers was enriched by individual suggestions of the authors of the present review.

Evidence Synthesis: DWI-MRI in detection of lymph node invasion has a sensitivity and specificity of 41 and 94%, respectively. For SPIO MRI using ferumoxtran-10, the sensitivity for detection of LNM with short axis diameter of 5–10 mm is reported at 96.4%, compared to 28.5% with MRI alone. PSMA PET/CT is growing exponentially, both in the initial detection of LNM and for BCR evaluation. Fluciclovine PET could improve detection of subcentimetric pathologic lymph nodes. Sentinel lymph node techniques remain experimental and not validated in the field of PCa.

Conclusions: Molecular imaging, particularly PSMA ligand PET imaging, present interesting diagnostic accuracy in LN diagnosis even in subcentimetric LN. DWI-MRI yields good results in LN involvement evaluation and the use of contrast agent such SPIO may improve the detection rate. The SLN technique is limited to experimental protocols and for intermediate or high-risk PCa. Prospective trials are awaited to evaluate the true clinical impact of these imaging techniques on PCa oncologic outcomes.

An overview of nanoscale radionuclides and radiolabeled nanomaterials commonly used for nuclear molecular imaging and therapeutic functions

Recent advances in the field of nanotechnology applications in nuclear medicine offer the promise of better diagnostic and therapeutic options. In recent years, increasing efforts have been focused on developing nanoconstructs that can be used as core platforms for attaching medical radionuclides with different strategies for the purposes of molecular imaging and targeted drug delivery. This review article presents an introduction to some commonly used nanomaterials with zero-dimensional, one-dimensional, two-dimensional, and three-dimensional structures, describes the various methods applied to radiolabeling of nanomaterials, and provides illustrative examples of application of the nanoscale radionuclides or radiolabeled nanocarriers in nuclear nanomedicine. Especially, the passive and active nanotargeting delivery of radionuclides with illustrating examples for tumor imaging and therapy was reviewed and summarized. The accurate and early diagnosis of cancer can lead to increased survival rates for different types of this disease. Although, the conventional single-modality diagnostic methods such as positron emission tomography/single photon emission computed tomography or MRI used for such purposes are powerful means; most of these are limited by sensitivity or resolution. By integrating complementary signal reporters into a single nanoparticulate contrast agent, multimodal molecular imaging can be performed as scalable images with high sensitivity, resolution, and specificity. The advent of radiolabeled nanocarriers or radioisotope-loaded nanomaterials with magnetic, plasmonic, or fluorescent properties has stimulated growing interest in the developing multimodality imaging probes. These new developments in nuclear nanomedicine are expected to introduce a paradigm shift in multimodal molecular imaging and thereby opening up an era of new diagnostic medical imaging agents. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 107A: 251-285, 2019.

Magnetic resonance sentinel lymph node imaging and magnetometer-guided intraoperative detection in prostate cancer using superparamagnetic iron oxide nanoparticles

Purpose

Sentinel lymph node (LN) dissection (sLND) using a magnetometer and superpara-magnetic iron oxide nanoparticles (SPION) as a tracer was successfully applied in prostate cancer (PCa). The feasibility of sentinel LN (SLN) visualization on MRI after intraprostatic SPION injection has been reported. In the present study, results of preoperative MRI identification of SLNs and the outcome of subsequent intraoperative magnetometer-guided sLND following intraprostatic SPION injection were studied in intermediate- and high-risk PCa.

Patients and methods

A total of 50 intermediate- and high-risk PCa patients (prostate-specific antigen >10 ng/mL and/or Gleason score ≥7) scheduled for radical prostatectomy with magnetometer-guided sLND and extended pelvic LND (eLND), were included. Patients underwent MRI before and one day after intraprostatic SPION injection using T1-, T2-, and T2*-weighted sequences. Diagnostic rate per patient was established. Distribution of SLNs per anatomic region was registered. Diagnostic accuracy of sLND was assessed by using eLND as a reference standard.

Results

SPION-MRI identified a total of 890 SLNs (median 17.5; IQR 12–22.5). SLNs could be successfully detected using MRI in all patients (diagnostic rate 100%). Anatomic SLN distribution: external iliac 19.2%, common iliac 16.6%, fossa obturatoria 15.8%, internal iliac 13.8%, presacral 12.1%, perirectal 12.0%, periprostatic 3.7%, perivesical 2.3%, and other regions 4.4%. LN metastases were intraoperatively found in 15 of 50 patients (30%). sLND had a 100% diagnostic rate, 85.7% sensitivity, 97.2% specificity, 92.3% positive predictive value, 94.9% negative predictive value, false negative rate 14.3%, and 2.8% additional diagnostic value (LN metastases only outside the eLND template).

Conclusion

MR scintigraphy after intraprostatic SPION injection provides a roadmap for intraoperative magnetometer-guided SLN detection and can be useful to characterize a reliable lymphadenectomy template. Draining LN from the prostate can be identified in an unexpectedly high number, especially outside the established eLND template. Further studies are required to analyze discordance between the number of pre- and intraoperatively identified SLNs.

Sentinel node evaluation in prostate cancer

Sentinel lymph node (SLN) based pelvic lymph node dissection (PLND) in prostate cancer (PCa) is appealing over the time, cost and morbidity classically attributed to conventional PLND during radical prostatectomy. The initial report of feasibility of the SLN concept in prostate cancer was nearly 20 years ago. However, PLND based on the SLN concept, either SLN biopsy of a single node or targeted SLN dissection of multiple nodes, is still considered investigational in PCa. To better appreciate the challenges, and potential solutions, associated with SLN-based PLND in PCa, this review will discuss the rationale behind PLND in PCa and evaluate current SLN efforts in the most commonly diagnosed malignancy in men in the US.

Multispectral-Fluorescence Imaging as a Tool to Separate Healthy from Disease-Related Lymphatic Anatomy During Robot-Assisted Laparoscopy

To reduce the invasive nature of extended pelvic lymph node (LN) dissections in prostate cancer, we have developed a multispectral-fluorescence guidance approach that enables discrimination between prostate-draining LNs and lower-limb-draining LNs. Methods: In 5 pigs, multispectral-fluorescence guidance was used on da Vinci Si and da Vinci Xi robots. The animals received fluorescein into the lower limb and indocyanine green-nanocolloid into the prostate. Results: Fluorescein was detected in 29 LNs (average of 3.6 LNs/template), and indocyanine green-nanocolloid was detected in 12 LNs (average of 1.2 LNs/template). Signal intensities appeared equal for both dyes, and no visual overlap in lymphatic drainage patterns was observed. Furthermore, fluorescein supported both the identification of leakage from damaged lymphatic structures and the identification of ureters. Conclusion: We demonstrated that the differences in lymphatic flow pattern between the prostate and lower limbs could be intraoperatively distinguished using multispectral-fluorescence imaging.

Magnetic Marking and Intraoperative Detection of Primary Draining Lymph Nodes in High-Risk Prostate Cancer Using Superparamagnetic Iron Oxide Nanoparticles: Additional Diagnostic Value

Sentinel lymph node dissection (sLND) using a magnetometer and superparamagnetic iron oxide nanoparticles (SPIONs) as a tracer was successfully applied in prostate cancer (PCa). Radioisotope-guided sLND combined with extended pelvic LND (ePLND) achieved better node removal, increasing the number of affected nodes or the detection of sentinel lymph nodes outside the established ePLND template. We determined the diagnostic value of additional magnetometer-guided sLND after intraprostatic SPION-injection in high-risk PCa. This retrospective study included 104 high-risk PCa patients (PSA >20 ng/mL and/or Gleason score ≥ 8 and/or cT2c) from a prospective cohort who underwent radical prostatectomy with magnetometer-guided sLND and ePLND. The diagnostic accuracy of sLND was assessed using ePLND as a reference standard. Lymph node metastases were found in 61 of 104 patients (58.7%). sLND had a 100% diagnostic rate, 96.6% sensitivity, 95.6% specificity, 96.6% positive predictive value, 95.6% negative predictive value, 3.4% false negative rate, and 4.4% false positive rate (detecting lymph node metastases outside the ePLND template). These findings demonstrate the high sensitivity and additional diagnostic value of magnetometer-guided sLND, exceeding that of ePLND through the individualized extension of PLND or the detection of sentinel lymph nodes/lymph node metastases outside the established node template in high-risk PCa.

Updated Nomogram Incorporating Percentage of Positive Cores to Predict Probability of Lymph Node Invasion in Prostate Cancer Patients Undergoing Sentinel Lymph Node Dissection

Objectives: To update the first sentinel nomogram predicting the presence of lymph node invasion (LNI) in prostate cancer patients undergoing sentinel lymph node dissection (sPLND), taking into account the percentage of positive cores. Patients and Methods: Analysis included 1,870 prostate cancer patients who underwent radioisotope-guided sPLND and retropubic radical prostatectomy. Prostate-specific antigen (PSA), clinical T category, primary and secondary biopsy Gleason grade, and percentage of positive cores were included in univariate and multivariate logistic regression models predicting LNI, and constituted the basis for the regression coefficient-based nomogram. Bootstrapping was applied to generate 95% confidence intervals for predicted probabilities. The area under the receiver operator characteristic curve (AUC) was obtained to quantify accuracy. Results: Median PSA was 7.68 ng/ml (interquartile range (IQR) 5.5-12.3). The number of lymph nodes removed was 10 (IQR 7-13). Overall, 352 patients (18.8%) had LNI. All preoperative prostate cancer characteristics differed significantly between LNI-positive and LNI-negative patients (P<0.001). In univariate accuracy analyses, the proportion of positive cores was the foremost predictor of LNI (AUC, 77%) followed by PSA (71.1%), clinical T category (69.9%), and primary and secondary Gleason grade (66.6% and 61.3%, respectively). For multivariate logistic regression models, all parameters were independent predictors of LNI (P<0.001). The nomogram exhibited a high predictive accuracy (AUC, 83.5%). Conclusion: The first update of the only available sentinel nomogram predicting LNI in prostate cancer patients demonstrates even better predictive accuracy and improved calibration. As an additional factor, the percentage of positive cores represents the leading predictor of LNI. This updated sentinel model should be externally validated and compared with results of extended PLND-based nomograms.

Sentinel node biopsy and lymphatic mapping in penile and prostate cancer

BACKGROUND

Nodal metastases are linked to poor outcome in men with penile or prostate cancer. Early detection and resection are important for staging and for the prognosis. However, lymphadenectomy is associated with morbidity and may miss metastases when performed solely on the basis of anatomical templates.

METHODS

In this article we describe the technique and benefits of sentinel node biopsy (SNB) and provide a review of the literature.

RESULTS

Dynamic sentinel node techniques using both radioactive and optical (hybrid) tracers have been proven effective in penile cancer. For prostate cancer, SNB added to extended nodal dissection may further tailor dissection to the highly variable lymphatic drainage patterns in the pelvis. The sensitivity of SNB was found to be superior to conventional imaging methods; however, false-negative SNB procedures can occur and a complementary extensive lymphadenectomy is required to remove additional positive nodes that were not detected in the SNB template.

CONCLUSION

SNB is a standard method for early detection of nodal metastases in penile cancer and provides superior diagnostic accuracy to conventional imaging modalities in prostate cancer.

Validation and head-to-head comparison of three nomograms predicting probability of lymph node invasion of prostate cancer in patients undergoing extended and/or sentinel lymph node dissection

PURPOSE

The updated Winter nomogram is the only nomogram predicting lymph node invasion (LNI) in prostate cancer (PCa) patients based on sentinel node (SN) dissection (sLND). The aim of the study was to externally validate the Winter nomogram and examine its performance in patients undergoing extended pelvic lymph node dissection (ePLND), ePLND combined with SN biopsy (SNB) and sLND only. The results were compared with the Memorial Sloan Kettering Cancer Center (MSKCC) and updated Briganti nomograms.

METHODS

This retrospective study included 1183 patients with localized PCa undergoing robot-assisted laparoscopic radical prostatectomy (RARP) combined with pelvic lymphadenectomy and 224 patients treated with sLND and external beam radiotherapy (EBRT), aiming to offer pelvic radiotherapy only in case of histologically positive SNs. In the RARP population, ePLND was applied in 956 (80.8%) patients,while 227 (19.2%) patients were offered ePLND combined with additional SNB.

RESULTS

The median numbers of removed nodes were 10 (interquartile range, IQR = 6-14), 15 (IQR = 10-20) and 7 (IQR = 4-10) in the ePLND, ePLND + SNB, and sLND groups, respectively. Corresponding LNI rates were 16.6%, 25.5% and 42%. Based on the AUC, the performance of the Briganti nomogram (0.756) in the ePLND group was superior to both the MSKCC (0.744) and Winter nomogram (0.746). The Winter nomogram, however, was the best predictor of LNI in both the ePLND + SNB (0.735) and sLND (0.709) populations. In the calibration analysis, all nomograms showed better accuracy in the low/intermediate risk patients, while in the high-risk population, an overestimation of the risk for LNI was observed.

CONCLUSION

The SN-based updated nomogram showed better prediction in the SN population. The results were also comparable, relative to predictive tools developed with (e)PLND, suggesting a difference in sampling accuracy between SNB and non-SNB. Patients who benefit most from the nomogram would be those with a low/intermediate risk of LN metastasis.

Imaging on nodal staging of prostate cancer

Prostate cancer is the second most common cancer in men and is the second highest cause of cancer death in men of all races. Accurate lymph node staging is essential to ensure adequate treatment of prostate cancer. Historically, conventional imaging methods have demonstrated limited sensitivity and specificity in the detection of lymph node metastases. There are many emerging PET tracers that have recently proven to be effective. In addition, the use of ultrasmall iron oxide nanoparticle-enhanced MRI has demonstrated promising results. This review outlines the strengths and limitations of each of the different imaging modalities as well as individual tracers used, including preclinical and clinical agents.

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

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

Sentinel lymph node detection during radical prostatectomy for prostate cancer: current evidence and results of our experience

PURPOSE

A sentinel lymph node (SNL) is the primary landing zone of cancer cells that spreads through the lymphatic vessels. The rational of the detection of sentinel node (SLN) during radical prostatectomy (RP) for prostate cancer (PCa) is the removal of the first nodal stations to provide a restriction of the template of node dissection. A review of the outcomes of SNL detection during RP for PCa was performed.

MATERIALS AND METHODS

A systematic review of the literature was conducted, searching on PubMed and Web of Science, using the following keywords: lymph node dissection, prostatic neoplasm, sentinel node.

RESULTS

Twenty articles were selected and analyzed including over 2000 PCa patients. Although promising and technically feasible, many points remain to be clarified before clinical application can be recommended.

CONCLUSIONS

The technique of SNL detection is feasible and provides a higher sensitivity and detection rate than standard lymphadenectomy, especially for organ-confined tumors. Larger series and long-term follow-up data are mandatory to assess the oncologic effectiveness of the detection of SNL for PCa.

Lymph node staging in prostate cancer: perspective for the pathologist

Pelvic lymph node dissection (PLND) currently represents the gold standard method for nodal staging in the setting of localised prostate cancer and may also have a therapeutic benefit in certain patients. The histopathological evaluation of PLND specimens plays a critical role in accurate lymph node staging, however there is currently a lack of consensus regarding the optimum approach and no quality parameters are in place. In addition, there are no guidelines as to the handling of less commonly encountered nodal specimens such as those identified within the anterior fat pad. This summary provides an overview of pertinent issues regarding lymph node staging in prostate cancer, with a focus on the histopathological evaluation of resected nodal specimens. We hope that this review will further the discussion on how to achieve a more standardised approach to the processing and reporting of PLND specimens in the setting of prostate cancer.

An indigenous single-vial kit formulation of human serum albumin nanocolloid for use in sentinel lymph node detection

OBJECTIVE

In-situ sentinel lymph node (SLN) detection is an important component in staging cancers of various origins. At present, technetium-99m (Tc)-labeled nanoparticle formulations like sulfur colloid and human serum albumin (HSA) nanocolloid are used in the clinic as SLN tracers. In India, HSA nanocolloid cold kits have so far been imported. This study aims to develop and evaluate an indigenous alternative to imported HSA nanocolloid cold kits for SLN detection/imaging.

MATERIALS AND METHODS

Production of cold kits was standardized and the product was characterized for its suitability in terms of particle size. Tc-labeling of an in-house HSA nanocolloid was optimized, and the yield and stability of the product were assessed. Animal studies were performed in Wistar rats using the footpad model. Clinical evaluation was performed in 54 patients using a combination of scintigraphic imaging and a hand-held gamma probe.

RESULTS AND CONCLUSION

With the optimized protocol, HSA nanocolloids with particle sizes ranging from 50 to 200 nm were obtained. Greater than 90% Tc-labeling yield was obtained in 15 min reactions, and the radiopharmaceutical was stable for up to 24 h after preparation. The animal studies showed similar SLN uptake and improved retention pattern compared with those of the imported Nanocoll radiopharmaceutical. Clinical studies showed detectable 'hot' nodes in 53 of 54 patients, demonstrating sensitivity of the product for clinical utility. In conclusion, this indigenous HSA nanocolloid cold kit is proposed as a logistically favorable alternative to imported kits for SLN detection in the Indian clinical scenario.

Sentinel lymph node biopsy in renal malignancy: The past, present and future

Sentinel lymph node biopsy (SLNB) is now an established technique in penile and pelvic cancers, resulting in a lower mortality and morbidity when compared with the traditional lymph node dissection. In renal cancer however, despite some early successes for the SLNB technique, paucity of data remains a problem, thus lymph node dissection and extended lymph node dissection remain the management of choice in clinically node positive patients, with surveillance of lymph nodes in those who are clinically node negative. SLNB is a rapidly evolving technique and the introduction of new techniques such as near infra-red fluorescence optical imaging agents and positron emission tomography/computed tomography scans, may improve sensitivity. Evidence in support of this has already been recorded in bladder and prostate cancer. Although the lack of large multi-centre studies and issues around false negativity currently prevent its widespread use, with evolving techniques improving accuracy and the support of large-scale studies, SLNB does have the potential to become an integral part of staging in renal malignancy.

First Robotic SPECT for Minimally Invasive Sentinel Lymph Node Mapping

In this paper we present the usage of a drop-in gamma probe for intra-operative Single-Photon Emission Computed Tomography (SPECT) imaging in the scope of minimally invasive robot-assisted interventions. The probe is designed to be inserted and reside inside the abdominal cavity during the intervention. It is grasped during the procedure using a robotic laparoscopic gripper enabling full six degrees of freedom handling by the surgeon. We demonstrate the first deployment of the tracked probe for intra-operative in-patient robotic SPECT enabling augmented-reality image guidance. The hybrid mechanical- and image-based in-patient probe tracking is shown to have an accuracy of 0.2 mm. The overall system performance is evaluated and tested with a phantom for gynecological sentinel lymph node interventions and compared to ground-truth data yielding a mean reconstruction accuracy of 0.67 mm.

Diagnostic yield and complications of extended lymphadenectomy versus limited lymphadenectomy combined with radical prostatectomy

BACKGROUND

Lymphadenectomy for prostate cancer (PC) is the most reliable procedure for detecting lymphatic metastases. The optimal extension of this procedure is still a topic of debate.

OBJECTIVE

To analyse the diagnostic performance and complications of extended lymphadenectomy (ELD) and limited lymphadenectomy (LLD) in a series of patients with high-risk PC who underwent radical prostatectomy (RP).

MATERIAL AND METHODS

A retrospective study was conducted on patients with high d'Amico risk who underwent RP with lymphadenectomy between 1999 and 2014. A comparative analysis was performed of the diagnostic capacity of lymphatic metastases of ELD and LLD and of postoperative complications at 90 days.

RESULTS

Ninety-three patients were analysed, 20 (21.5%) and 73 (78.5%) of whom underwent ELD and LLD, respectively. The mean age of the series was 65.26 years (SD, 5.51). The median follow-up was 1.51 (0.61-2.29) years in the ELD group and 5.94 (3.61-9.10) in the LLD group. The median number of nodes obtained was 13 (9-23) in the ELD group compared with 5 (2-8) in the LLD group (p <.001). The percentages of patients with positive nodes in the ELD and LLD groups were 35% and 5.47%, respectively (p <.001). The overall complication rate at 90 days was 35.5% (33 patients). In the ELD group, 12 patients (60%) had complications, compared with 21 patients (28.8%) in the LLD group (p=.016), with no significant differences in severity according to the Clavien scale (p=.73).

CONCLUSIONS

In our series, the detection of metastatic nodes was significantly greater with ELD. ELD increases the number of complications, with no differences compared with LLD in severity according to the modified Clavien scale.

Multimodal hybrid imaging agents for sentinel node mapping as a means to (re)connect nuclear medicine to advances made in robot-assisted surgery

Purpose

Radical prostatectomy and complementary extended pelvic lymph node dissection (ePLND) of sentinel lymph nodes (SNs) and non-sentinel lymph nodes (LNs) at risk of containing metastases are increasingly being performed using high-tech robot-assisted approaches. Although this technological evolution has clear advantages, the physical nature of robotic systems limits the integrated use of routine radioguided surgery technologies. Hence, engineering effort in robotics are focused on the integration of fluorescence guidance technologies. Using the hybrid SN tracer indocyanine green-^99mTc-nanocolloid (radioactive and fluorescent), for the first time in combination with a robot-integrated laparoscope, we investigated whether the robot-assisted approach affects the accuracy of fluorescence detection of SNs identified preoperatively using nuclear medicine.

Methods

The study included 55 patients (Briganti nomogram-based risk >5 % on LN metastases) scheduled for robot-assisted radical prostatectomy, SN biopsy and ePLND. Following indocyanine green-^99mTc-nanocolloid injection, preoperative nuclear imaging (lymphoscintigraphy and SPECT/CT) was used to locate the SN(s). The fluorescence laparoscope was used intraoperatively to identify the SN(s) with standard fluorescence settings (in 50 patients) and with customized settings (in 5 patients). The number and location of the SNs, the radioactive, fluorescence (both in vivo and ex vivo) and tumour status of the resected SNs/LNs, and postoperative complications were recorded and analysed.

Results

Combined, preoperative lymphoscintigraphy and SPECT/CT imaging identified 212 SNs (median 4 per patient). Intraoperative fluorescence imaging using standard fluorescence settings visualized 80.4 % (148/184 SNs; 50 patients; ex vivo 97.8 %). This increased to 85.7 % (12/14 SNs; 5 patients; ex vivo 100 %) with customized fluorescence settings. SPECT/CT images provided guidance towards the residual SNs. Ex vivo all removed SNs were radioactive. SNs were tumour-positive in 25.4 % of patients (14/55; false-negative rate 7 %, 1/14 patients). In ten patients, the SN was the only tumour-positive LN. Surgical complications were minimal.

Conclusion

Directly linking 3D preoperative nuclear imaging information on SNs to a robot-integrated fluorescence laparoscope improved the surgeon’s use of the technology and did not influence the sensitivity or morbidity of the procedure. To our surprise, however, the detection rates with the current fluorescence camera did not improve.

Sentinel lymph node imaging guided IMRT for prostate cancer: Individualized pelvic radiation therapy versus RTOG guidelines

Purpose/Objectives

Current Radiation Therapy Oncology Group (RTOG) guidelines for pelvic radiation therapy are based on general anatomic boundaries. Sentinel lymph node (SLN) imaging can identify potential sites of lymph node involvement. We sought to determine how tailored radiation therapy fields for prostate cancer would compare to standard RTOG-based fields. Such individualized radiation therapy could prioritize the most important areas to irradiate while potentially avoiding coverage in areas where critical structures would be overdosed. Individualized radiation therapy could therefore increase the therapeutic index of pelvic radiation therapy.

Methods and materials

Ten intermediate or high-risk prostate cancer patients received androgen deprivation therapy with definitive radiation therapy, including an SLN imaging–tailored elective nodal volume (ENV). For dosimetric analyses, the ENV was recontoured using RTOG guidelines (RTOG_ENV) and on SLNs alone (SLN_ENV). Separate intensity modulated radiation therapy (IMRT) plans were optimized using RTOG_ENV and SLN_ENV for each patient. Dosimetric comparisons for these IMRT plans were performed for each patient. Dose differences to targets and critical structures among the different IMRT plans were calculated. Distributions of dose parameters were analyzed using non-parametric methods.

Results

Sixty percent of patients had SLNs outside of the RTOG_ENV. The larger volume IMRT plans covering SLN imaging–tailored elective nodal volume exhibited no significant dose differences versus plans covering RTOG_ENV. IMRT plans covering only the SLNs had significantly lower doses to bowel and femoral heads.

Conclusions

SLN-guided pelvic radiation therapy can be used to either treat the most critical nodes only or as an addition to RTOG guided pelvic radiation therapy to ensure that the most important nodes are included.

Update on histopathological evaluation of lymphadenectomy specimens from prostate cancer patients

BACKGROUND

Metastases to lymph nodes (LNs) represent an unfavorable prognostic factor in patients with prostate cancer (PCa). Histological examination represents the gold standard in the evaluation of the lymphadenectomy (LND) specimens for the presence of secondary deposits.

METHODS AND RESULTS

The metastatic detection rate can vary according to the approach adopted in the microscopic analysis of the LNs, which includes frozen-section examination, total inclusion of the tissue with and without whole-mount sections, serial sectioning, and the application of immunohistochemistry. The assessment of the sentinel LN, the search for micrometastases, and the evaluation of atypical LN metastatic sites further contribute to the detection of the metastatic spread.

CONCLUSION

In this review, an update on the histopathological evaluation of LND specimens in patients with PCa is given, and focus is made on their clinical and prognostic significance.

Pelvic lymph node dissection in prostate cancer: indications, extent and tailored approaches

PURPOSE

The purpose of this study is to review the current literature concerning the indication of pelvic lymph node dissection (PLND), its extent and complications in prostate cancer (PCa) staging, the available tools, and the future perspectives to assess the risk of lymph node invasion (LNI).

METHODS

A literature review was performed using the Medline, Embase, and Web of Science databases. The search strategy included the terms pelvic lymph nodes, PLND, radical prostatectomy, prostate cancer, lymph node invasion, biochemical recurrence, staging, sentinel lymph node dissection, imaging, and molecular markers.

RESULTS

PLND currently represents the gold standard for nodal staging in PCa patients. Available imaging techniques are characterized by poor accuracy in the prediction of LNI before surgery. On the contrary, an extended PLND (ePLND) would result into proper staging in the majority of the cases. Several models based on preoperative disease characteristics are available to assess the risk of LNI. Although ePLND is not associated with a substantial risk of severe complications, up to 10% of the men undergoing this procedure experience lymphoceles. Concerns over potential morbidity of ePLND led many authors to investigate the role of sentinel lymph node dissection in order to prevent unnecessary ePLND. Finally, the incorporation of novel biomarkers in currently available tools would improve our ability to identify men who should receive an ePLND.

CONCLUSIONS

Nowadays, the most informative tools predicting LNI in PCa patients consist in preoperative clinical nomograms. Sentinel lymph node dissection still remains experimental and novel biomarkers are needed to identify patients at a higher risk of LNI.

Sentinel node approach in prostate cancer

In general terms, one of the main objectives of sentinel lymph node (SLN) biopsy is to identify the 20-25% of patients with occult regional metastatic involvement. This technique reduces the associated morbidity from lymphadenectomy, as well as increasing the identification rate of occult lymphatic metastases by offering the pathologist those lymph nodes with the highest probability of containing metastatic cells. Pre-surgical lymphoscintigraphy is considered a "road map" to guide the surgeon towards the sentinel nodes and to ascertain unpredictable lymphatic drainages. In prostate cancer this aspect is essential due to the multidirectional character of the lymphatic drainage in the pelvis. In this context the inclusion of SPECT/CT should be mandatory in order to improve the SLN detection rate, to clarify the location when SLNs are difficult to interpret on planar images, to achieve a better definition of them in locations close to injection site, and to provide anatomical landmarks to be recognized during operation to locate SLNs. Conventional and laparoscopic hand-held gamma probes allow the SLN technique to be applied in any kind of surgery. The introduction and combination of new tracers and devices refines this technique, and the use of intraoperative images. These aspects become of vital importance due to the recent incorporation of robot-assisted procedures for SLN biopsy. In spite of these advances various aspects of SLN biopsy in prostate cancer patients still need to be discussed, and therefore their clinical application is not widely used.

Nuclear molecular imaging with nanoparticles: radiochemistry, applications and translation

Molecular imaging provides considerable insight into biological processes for greater understanding of health and disease. Numerous advances in medical physics, chemistry and biology have driven the growth of this field in the past two decades. With exquisite sensitivity, depth of detection and potential for theranostics, radioactive imaging approaches have played a major role in the emergence of molecular imaging. At the same time, developments in materials science, characterization and synthesis have led to explosive progress in the nanoparticle (NP) sciences. NPs are generally defined as particles with a diameter in the nanometre size range. Unique physical, chemical and biological properties arise at this scale, stimulating interest for applications as diverse as energy production and storage, chemical catalysis and electronics. In biomedicine, NPs have generated perhaps the greatest attention. These materials directly interface with life at the subcellular scale of nucleic acids, membranes and proteins. In this review, we will detail the advances made in combining radioactive imaging and NPs. First, we provide an overview of the NP platforms and their properties. This is followed by a look at methods for radiolabelling NPs with gamma-emitting radionuclides for use in single photon emission CT and planar scintigraphy. Next, utilization of positron-emitting radionuclides for positron emission tomography is considered. Finally, recent advances for multimodal nuclear imaging with NPs and efforts for clinical translation and ongoing trials are discussed.

Reliability of sentinel node procedure for lymph node staging in prostate cancer patients at high risk for lymph node involvement

AIM

To investigate the reliability of a sentinel node (SN) procedure for nodal staging in prostate cancer (PCa) patients at high risk for lymph node (LN) involvement.

MATERIAL AND METHODS

Seventy-four patients with localized prostate adenocarcinoma, who were clinically node-negative and had a risk of LN involvement of ≥ 10% (Partin tables), were prospectively enrolled. Upon intraprostatic 99mTc-nanocolloid injection, they underwent planar scintigraphy and SPECT imaging. Surgical removal of the SN, located by means of a gamma probe, was completed with a superextended LN dissection (seLND) as a reference and followed by radical prostatectomy.

RESULTS

In total, 470 SN (median 6, IQR 3-9) were scintigraphically detected of which 371 (median 4, IQR 2-6) were located by gamma probe and selectively removed during surgery (79%). Histopathology confirmed LN metastases in 37 patients (50%) having 106 affected LN in total (median number per patient 2, IQR 1-4). Twenty-eight patients were node positive (N+) based on the analysis of the resected SN. However, the seLND that was performed as a reference revealed nine additional N+ patients resulting in a sensitivity of 76% (28/37). In total, 15 of 37 patients (41%) had metastases in SN only and could have been spared seLND to remove all affected nodes.

CONCLUSION

We found a relatively low sensitivity when addressing the SN procedure for nodal staging in PCa patients at high risk for LN involvement. Importantly, only less than half of the N+ patients could have been spared a seLND to remove all affected lymphoid tissue.

Magnetic resonance sentinel lymph node imaging of the prostate with gadofosveset trisodium-albumin: preliminary results in a canine model

RATIONALE AND OBJECTIVES

To determine if intraprostatic injection of gadofosveset trisodium mixed with human serum albumin (HSA) can identify sentinel lymph nodes (LNs) draining the prostate on magnetic resonance imaging (MRI) in a canine model.

MATERIALS AND METHODS

Three male canines weighing between 25.7 and 41.3 kg were anesthetized, placed in a 3-T MRI, and a needle was placed transrectally into one side of the prostate using a commercially available intrarectal needle guide. Gadofosveset trisodium premixed with 10% HSA was then administered at doses ranging from 0.1 to 2.5 mL. T1W MRI was performed immediately after injection, and two readers evaluated images for visualization of LNs draining the prostate.

RESULTS

Intraprostatic injection of 0.2 mL gadofosveset trisodium premixed with HSA identified the draining periprostatic LNs in all cases. Delayed images demonstrated upper echelon nodes in the pelvis and the abdomen. Higher volume injections resulted in excessive periprostatic extravasation, whereas lower volume injections resulted in suboptimal visualization of LNs.

CONCLUSIONS

We demonstrate that gadofosveset trisodium (premixed with 10% HSA) injected intraprostatically at 0.2 mL visualized LNs draining the prostate. This approach can be readily adapted for clinical applications such as sentinel LN imaging in prostate cancer patients before surgery.