Fluorescence guidance in urologic surgery

Subsurface fluorescence time-of-flight imaging using a large-format single-photon avalanche diode sensor for tumor depth assessment

Significance

Fluorescence guidance is used clinically by surgeons to visualize anatomical and/or physiological phenomena in the surgical field that are difficult or impossible to detect by the naked eye. Such phenomena include tissue perfusion or molecular phenotypic information about the disease being resected. Conventional fluorescence-guided surgery relies on long, microsecond scale laser pulses to excite fluorescent probes. However, this technique only provides two-dimensional information; crucial depth information, such as the location of malignancy below the tissue surface, is not provided.

Aim

We developed a depth sensing imaging technique using light detection and ranging (LiDAR) time-of-flight (TOF) technology to sense the depth of target tissue while overcoming the influence of tissue optical properties and fluorescent probe concentration.

Approach

The technology is based on a large-format (512 × 512   pixel ), binary, gated, single-photon avalanche diode (SPAD) sensor with an 18 ps time-gate step, synchronized with a picosecond pulsed laser. The fast response of the sensor was developed and tested for its ability to quantify fluorescent inclusions at depth and optical properties in tissue-like phantoms through analytical model fitting of the fast temporal remission data.

Results

After calibration and algorithmic extraction of the data, the SPAD LiDAR technique allowed for sub-mm resolution depth sensing of fluorescent inclusions embedded in tissue-like phantoms, up to a maximum of 5 mm in depth. The approach provides robust depth sensing even in the presence of variable tissue optical properties and separates the effects of fluorescence depth from absorption and scattering variations.

Conclusions

LiDAR TOF fluorescence imaging using an SPAD camera provides both fluorescence intensity images and the temporal profile of fluorescence, which can be used to determine the depth at which the signal is emitted over a wide field of view. The proposed tool enables fluorescence imaging at a higher depth in tissue and with higher spatial precision than standard, steady-state fluorescence imaging tools, such as intensity-based near-infrared fluorescence imaging, optical coherence tomography, Raman spectroscopy, or confocal microscopy. Integration of this technique into a standard surgical tool could enable rapid, more accurate estimation of resection boundaries, thereby improving the surgeon's efficacy and efficiency, and ultimately improving patient outcomes.

Evaluation of testicular blood flow during testicular torsion surgery in children using the indocyanine green-guided near-infrared fluorescence imaging technique

Objective

This study investigates the feasibility of the indocyanine green-guided near-infrared fluorescence (ICG-NIRF) imaging technique in evaluating testicular blood flow during testicular torsion (TT) surgery in pediatric cases.

Methods

We retrospectively analyzed the eight pediatric patients with TT who underwent surgery in our hospital between February and July 2023. The intraoperative two-step method of ICG-NIRF imaging and testicular incision was used to evaluate the testicular blood flow, followed by a selection of different surgical methods. The removed testes were pathologically examined after surgery, and all patients were followed up 1 month after surgery to evaluate testicular blood flow using gray-scale ultrasound and color Doppler flow imaging (CDFI).

Results

Eight pediatric TT patients aged 1-16 years, with a median age of 11.5 years, were enrolled. Time from the onset ranged from 4 to 72 h (mean 26.13 ± 25.09 h). A total of eight testes were twisted, including four on the left side and four on the right side. The twisting direction of the testes was clockwise in four cases and counterclockwise in four cases. The rotation of torsion was 180°-1,080° (mean 472.5° ± 396°). There was no statistically significant difference in the imaging time between the four patients with testicular blood vessel imaging on both the torsional and normal sides (P > 0.05). The postoperative recovery was uneventful, with no complications during the follow-up period of 1 month. The postoperative histopathological results of three patients who underwent orchiectomy showed extensive hemorrhage, degeneration, and necrosis of the testicular tissue. Among the five patients who underwent orchiopexy, a gray-scale ultrasound and CDFI examinations showed uniform internal echo of the testes and normal blood flow signals in four patients. One patient with no testicular blood vessel imaging on the torsional side showed uneven internal echo of the testis and no blood flow signals.

Conclusion

ICG-NIRF imaging is a feasible method to evaluate testicular blood flow during TT surgery. Testicular blood vessel imaging within 5 minutes after ICG injection might be the basis for testicular retention during TT surgery.

Microsurgery Robots: Applications, Design, and Development

Microsurgical techniques have been widely utilized in various surgical specialties, such as ophthalmology, neurosurgery, and otolaryngology, which require intricate and precise surgical tool manipulation on a small scale. In microsurgery, operations on delicate vessels or tissues require high standards in surgeons' skills. This exceptionally high requirement in skills leads to a steep learning curve and lengthy training before the surgeons can perform microsurgical procedures with quality outcomes. The microsurgery robot (MSR), which can improve surgeons' operation skills through various functions, has received extensive research attention in the past three decades. There have been many review papers summarizing the research on MSR for specific surgical specialties. However, an in-depth review of the relevant technologies used in MSR systems is limited in the literature. This review details the technical challenges in microsurgery, and systematically summarizes the key technologies in MSR with a developmental perspective from the basic structural mechanism design, to the perception and human-machine interaction methods, and further to the ability in achieving a certain level of autonomy. By presenting and comparing the methods and technologies in this cutting-edge research, this paper aims to provide readers with a comprehensive understanding of the current state of MSR research and identify potential directions for future development in MSR.

Fluorescence-Guided Surgery and Novel Innovative Technologies for Improved Visualization in Pediatric Urology

Fluorescence-guided surgery (FGS), three-dimensional (3D) imaging technologies, and other innovative devices are rapidly revolutionizing the field of urology, providing surgeons with powerful tools for a more complete understanding of patient-specific anatomy. Today, several new intraoperative imaging technologies and cutting-edge devices are available in adult urology to assist surgeons in delivering personalized interventions. Their applications are also gradually growing in general pediatric surgery, where the detailed visualization of normal and pathological structures has the potential to significantly minimize perioperative complications and improve surgical outcomes. In the field of pediatric urology, FGS, 3D reconstructions and printing technologies, augmented reality (AR) devices, contrast-enhanced ultrasound (CEUS), and intraoperative magnetic resonance imaging (iMRI) have been increasingly adopted for a more realistic understanding of the normal and abnormal anatomy, providing a valuable insight to deliver customized treatments in real time. This narrative review aims to illustrate the main applications of these new technologies and imaging devices in the clinical setting of pediatric urology by selecting, with a strict methodology, the most promising articles published in the international scientific literature on this topic. The purpose is to favor early adoption and stimulate more research on this topic for the benefit of children.

Fluorescence-guided radical prostatectomy

Robotic-assisted laparoscopic radical prostatectomy represents one of the most common operations in urologic oncology and involves several critical technical steps including pelvic lymph node dissection, cavernous nerve sparing and vesicourethral anastomosis. The quality of performing these steps is linked to functional and oncological outcomes. Indocyanine green [ICG] is a non-radioactive, water-soluble compound which allows for enhanced visualization with near-infrared fluorescence of both anatomical structures and vasculature during complex abdominal operations such as prostatectomy. During the last decade, several investigators have examined the value and role of ICG fluorescence during prostatectomy. In this review, we sought to evaluate the body of evidence for fluorescence-guided robotic prostatectomy as well as assess potential future areas of investigation with this technology.

Application of the indocyanine green fluorescence imaging method in laparoscopic resection of a solitary retroperitoneal metastasis of renal cell carcinoma: A case report

Fluorescence image-guided surgery has improved intraoperative identification of anatomic structures including visualization of vascular anatomy. Herein, indocyanine green (ICG) fluorescence imaging was applied to identify of a recurrent small tumor of renal cell carcinoma (RCC) during laparoscopic surgery. The patient underwent left laparoscopic radical nephrectomy via the retroperitoneal approach for RCC (clear cell carcinoma, pT1bN0M0) at the age of 39 years. A solitary retroperitoneal mass (14 mm in diameter) was identified in a computed tomography scan 6 years after surgery. We performed laparoscopic resection with the application of the ICG angiography, because RCC is recognized as one of the most hypervascular cancers. The tumor was clearly visualized by fluorescence. Histopathological diagnosis of the resected tumor was recurrent RCC (low grade, G1). The patient remained free of disease at 2 years after surgery. The ICG fluorescence imaging would be a useful method for identification of metastatic small lesions of RCC during laparoscopic surgery.

Indocyanine green fluorescence imaging for laparoscopic complex upper urinary tract reconstructions: a comparative study

Background

To describe our technique for using an intraureteral injection of indocyanine green (ICG) and visualization under near-infrared fluorescence (NIRF) to facilitate challenging upper urinary tract reconstructions (UUTRs) and to present the comparative outcomes.

Methods

We collected 36 patients who underwent laparoscopic UUTRs between April 2019 and March 2020, and we divided the patients into two groups based on the use of ICG (ICG group and non-ICG group). Demographic characteristics, perioperative outcomes, and functional outcomes were compared between the two groups.

Results

There were 18 cases in the ICG group and 18 cases in the non-ICG group, respectively. There were no differences in the baseline characteristics between the two groups. The intraoperative time to identification of the ureter (TIU; 20.9±11.7 vs. 30.0±14.6 min, P=0.03) and length of postoperative hospital stay (LPHS; 11.1±3.0 vs. 16.6±10.0 days, P=0.03) were significantly shorter in the ICG group. There was also a trend for lesser time for locating the stricture (43.0±27.9 vs. 55.4±18.6 min, P=0.14) and lower estimated blood loss (EBL) in the ICG group patients (88.3±75.4 vs. 91.7±46.2 mL, P=0.22). During the mean 3.8-month follow-up for the ICG group and the 6.2-month for the non-ICG group, there was a trend for more severe complications in the non-ICG group.

Conclusions

Visualizing intraureteral ICG under NIRF is useful in challenging UUTRs, allows for rapid ureteral identification and accurate real-time delineation of the ureteral stricture margins, and provides encouraging follow-up outcomes compared with those in the non-ICG group.

Near-Infrared fluorescence imaging using indocyanine green (ICG): Emerging applications in pediatric urology

BACKGROUND

Near-infrared fluorescence (NIRF) imaging with indocyanine green (ICG) has been recently adopted in pediatric minimally invasive surgery (MIS) in order to improve intra-operative visualization of anatomic structures and facilitate surgery.

OBJECTIVE

This study aimed to report our preliminary experience using ICG technology in pediatric urology using laparoscopy and robotics.

STUDY DESIGN

ICG technology was adopted in 57 laparoscopic or robotic urological procedures performed in our unit over a 24-month period: 41 (38 laparoscopic - 3 robotic) left varicocele repairs with intra-operative lymphography and 16 renal procedures (12 laparoscopic - 4 robotic) including 9 partial nephrectomies, 3 nephrectomies and 4 renal cyst deroofings.

RESULTS

The ICG solution was injected intravenously in renal procedures or into the testis body in case of varicocele repair. Regarding the timing of the administration, the ICG injection was performed intra-operatively in all cases and allowed the visualization of the anatomic structures in a matter of 30-60 s. The dosage of ICG was 0.3 mg/mL/kg in all indications. All procedures were completed laparoscopically or robotically without conversions. No adverse and allergic reactions to ICG and other complications occurred postoperatively.

DISCUSSION

This paper describes for the first time in pediatric urology that ICG-guided NIRF imaging may be helpful in laparoscopic and robotic procedures. In case of varicocele repair, ICG-enhanced fluorescence allowed to perform a lymphatic-sparing procedure and avoid the risk of postoperative hydrocele. In case of partial nephrectomy, ICG-guided NIRF was helpful to visualize the vascularization of the non-functioning moiety, identify the dissection plane between the two moieties (Fig. 1) and check the perfusion of the residual parenchyma after resection of the non-functioning pole. In case of renal cyst deroofing, ICG-guided NIRF aided to identify the avascular cyst dome and to guide its resection. No real benefits of using ICG-enhanced fluorescence were observed during nephrectomy.

CONCLUSION

Our preliminary experience confirmed the safety and efficacy of ICG technology in pediatric urology and highlighted its potential advantages as adjunctive surgical technology in patients undergoing laparoscopic or robotic urological procedures. Use of NIRF was also cost-effective as no added costs were required except for the ICG dye (cost 40 eur per bottle). The most common and useful applications in pediatric urology included varicocele repair, partial nephrectomy ad renal cyst deroofing. The main limitation is the specific equipment needed in laparoscopy, that is not available in all centers whereas the robot is equipped with the Firefly® software for NIRF.

Robotic Partial Nephrectomy with Indocyanine Green Fluorescence Navigation

Partial nephrectomy (PN) is a recommended type of treatment of localised renal tumors. Real-time intraoperative imaging technique, such as fluorescence imaging with indocyanine green (ICG) administration helps to improve intraoperative and postoperative outcomes in patients who underwent PN. Our work presents results of patients who underwent robotic PN with ICG navigation. A total of 37 patients underwent robotic PN with application of ICG between April 2015 and May 2019. A total amount of 5 mg of ICG was applied intravenously, and then robotic PN was performed with fluorescent imaging. ICG was used by the surgeon's decision according to unfavourable anatomical properties of tumor or to high R.E.N.A.L. nephrometry score. An exact border between perfused and nonperfused tissue was detected, and exact tumor's branch of the renal artery was clamped. Robotic PN with ICG-fluorescence imaging navigation was performed in 37 cases with a preoperative average diameter of tumor of 31 mm. The mean surgery time was 133 minutes, and the mean estimated blood loss was 190 mL. Arterial clamping was performed in 35 cases. The mean duration of warm ischemia was 14 minutes. Application of ICG enabled specific tumor-supplying vessel clamping in 25 cases. Two complications of grade II according to the Clavien-Dindo classification occurred intraoperatively, and one complication of grade III was observed. Renal function changes showed favourable results for the cases with superselective clamping. Finally, an administration of ICG eases superselective clamping of tumor-specific branch of renal artery and helps to preserve normal renal function with acceptable oncological results.

Examining the technical feasibility of prostate cancer molecular imaging by transrectal photoacoustic tomography with transurethral illumination

To pave the road toward clinical application of photoacoustic imaging in prostate cancer (PCa) diagnosis, we studied the technical feasibility and performance of transrectal photoacoustic (PA) imaging in mapping the indocyanine green (ICG) contrast agent, which is approved by FDA, in entire prostates by using light illumination via the urethral track. Experiments were conducted on a clinically relevant ex vivo model involving whole human prostates harvested from radical prostatectomy. The light source placed in the urethral track was an array of light emitting diodes (LEDs), illuminating the prostate with a delivered light power on the urethral wall within the safety limit. A dual-modality imaging system acquired PA and ultrasound (US) images simultaneously in the same way as in transrectal ultrasound (TRUS), with the US imaging presenting the tissue structure and PA imaging detecting the ICG solution. The imaging results demonstrated that tubes containing ICG solution at different concentrations can be detected at different positions in the prostate within a 2 cm range around from the urethral wall. Considering the sizes of regular human prostates, the proposed transurethral illumination in combination with transrectal US detection can facilitate PA molecular imaging over the entire prostate in a non-invasive manner, which makes it possible to further improve the PCa diagnosing efficiency with better molecular sensitivity and resulted better biopsy accuracy and much reduced pain for patients.

Use of SPY Elite Fluorescence Imaging in Creation of a Continent Urinary Diversion

The use of SPY Elite Fluorescence Imaging has recently grown popular among multiple surgical specialties, including colorectal, plastic, endocrine, ophthalmologic, and vascular surgery, due to its ability to quickly and accurately assess tissue perfusion and guide intraoperative decision making. To our knowledge, the use of SPY imaging in urologic reconstructive surgery has yet to be reported. We present a case in which SPY imaging was used intraoperatively to assess perfusion of an ileocecal anastomosis and a segment of bowel prior to creation of a continent urinary diversion following radical cystectomy.

Robotic-Assisted Sentinel Lymph Node Mapping With Indocyanine Green in Pelvic Malignancies: A Systematic Review and Meta-Analysis

Objective: Newer technologies such as near-infrared (NIR) imaging of the fluorescent dye indocyanine green (ICG) and daVinci Xi Surgical System have become promising tools for sentinel lymph node (SLN) mapping. This meta-analysis was conducted to comprehensively evaluate the diagnostic value of SLN in assessing lymph nodal metastasis in pelvic malignancies, using ICG with NIR imaging in robotic-assisted surgery. Materials and Methods: A literature search was conducted using PubMed for studies in English before April 2019. The detection rate, sensitivity of SLN detection of metastatic disease, and factors associated with successful mapping (sample size, study design, mean age, mean body mass index, type of cancer) were synthesized for meta-analysis. Results: A total of 17 articles including 1,059 patients were finally included. The reported detection rates of SLN ranged from 76 to 100%, with a pooled average rate of 95% (95% CI: 93-97; 17 studies). The sensitivity of SLN detection of metastatic disease ranged from 50 to 100% and the pooled sensitivity was 86% (95% CI: 75-94; 8 studies). There were no complications related to ICG administration reported. Conclusions: NIR imaging system using ICG in robotic-assisted surgery is a feasible and safe method for SLN mapping. Due to its promising performance, it is considered to be an alternative to a complete pelvic lymph node dissection.

Indocyanine Green (ICG) in Urologic Surgery

Indocyanine green (ICG) is a dye used for fluorescent-guided surgery. This review article addresses the recent surge in reported uses of ICG in various surgical fields and provides a comprehensive and up to date review of the uses of ICG in urologic surgery.

Use of indocyanine green to minimise uretero-enteric strictures after robotic radical cystectomy

OBJECTIVE

To evaluate the impact of indocyanine green (ICG) for assessing ureteric vascularity on the rate of uretero-enteric stricture formation after robot-assisted radical cystectomy (RARC) with intracorporeal urinary diversion (ICUD).

PATIENTS AND METHODS

We identified 179 patients undergoing RARC and ICUD between January 2014 and May 2017, and divided the patients into two groups based on the utilisation of ICG for the assessment of ureteric vascularity (non-ICG group and ICG group). We retrospectively reviewed the medical records to identify the length of ureter excised. Demographic, perioperative outcomes (including 90-day complications and readmissions), and the rate of uretero-enteric stricture were compared between the two groups. The two groups were compared using the t-test for continuous variables and the chi-squared test for categorical variables. A P < 0.05 was considered statistically significant.

RESULTS

A total of 132 and 47 patients were in the non-ICG group and the ICG group, respectively. There were no differences in baseline characteristics and perioperative outcomes including operating time, estimated blood loss, and length of stay. The ICG group was associated with a greater length of ureter being excised during the uretero-enteric anastomosis and a greater proportion of patients having long segment (>5 cm) ureteric resection. The median follow-up was 14 and 12 months in the non-ICG and ICG groups, respectively. The ICG group was associated with no uretero-enteric strictures compared to a per-patient stricture rate of 10.6% and a per-ureter stricture rate of 6.6% in the non-ICG group (P = 0.020 and P = 0.013, respectively).

CONCLUSION

The use of ICG fluorescence to assess distal ureteric vascularity during RARC and ICUD may reduce the risk of ischaemic uretero-enteric strictures. The technique is simple, safe, and reproducible. Larger studies with longer follow-up are needed to confirm our findings.

Developing a personalized template for lymph node dissection during radical prostatectomy

Lymph node dissection (LND) represents a critical step in order to determine lymph node invasion (LNI), not only for prognostic means but also as a therapeutic strategy in the management of patients with prostate cancer (CaP). Indications for performing LND are inconsistent with the American Urologic Association (AUA), European Association of Urology (EAU), and National Comprehensive Cancer Network (NCCN) recommendations differing. A thorough appreciation of lymph node drainage patterns and extent of LND has reshaped our understanding of this disease. Moreover, newer research into this field has directly resulted in refinements to current nomograms with utilization of various prostate-specific antigen (PSA) parameters and genomic medicine. Lastly, the application of newer imaging modalities in combination with molecular-guided robotic surgery has personalized the approach of LND espousing excellent safety, efficacy, and oncologic outcomes in these patients.

Navigating surgical fluorescence cameras using near-infrared optical tracking

Fluorescence guidance facilitates real-time intraoperative visualization of the tissue of interest. However, due to attenuation, the application of fluorescence guidance is restricted to superficial lesions. To overcome this shortcoming, we have previously applied three-dimensional surgical navigation to position the fluorescence camera in reach of the superficial fluorescent signal. Unfortunately, in open surgery, the near-infrared (NIR) optical tracking system (OTS) used for navigation also induced an interference during NIR fluorescence imaging. In an attempt to support future implementation of navigated fluorescence cameras, different aspects of this interference were characterized and solutions were sought after. Two commercial fluorescence cameras for open surgery were studied in (surgical) phantom and human tissue setups using two different NIR OTSs and one OTS simulating light-emitting diode setup. Following the outcome of these measurements, OTS settings were optimized. Measurements indicated the OTS interference was caused by: (1) spectral overlap between the OTS light and camera, (2) OTS light intensity, (3) OTS duty cycle, (4) OTS frequency, (5) fluorescence camera frequency, and (6) fluorescence camera sensitivity. By optimizing points 2 to 4, navigation of fluorescence cameras during open surgery could be facilitated. Optimization of the OTS and camera compatibility can be used to support navigated fluorescence guidance concepts.

Imaging the pharmacology of nanomaterials by intravital microscopy: Toward understanding their biological behavior

Therapeutic nanoparticles (NPs) can deliver cytotoxic chemotherapeutics and other drugs more safely and efficiently to patients; furthermore, selective delivery to target tissues can theoretically be accomplished actively through coating NPs with molecular ligands, and passively through exploiting physiological "enhanced permeability and retention" features. However, clinical trial results have been mixed in showing improved efficacy with drug nanoencapsulation, largely due to heterogeneous NP accumulation at target sites across patients. Thus, a clear need exists to better understand why many NP strategies fail in vivo and not result in significantly improved tumor uptake or therapeutic response. Multicolor in vivo confocal fluorescence imaging (intravital microscopy; IVM) enables integrated pharmacokinetic and pharmacodynamic (PK/PD) measurement at the single-cell level, and has helped answer key questions regarding the biological mechanisms of in vivo NP behavior. This review summarizes progress to date and also describes useful technical strategies for successful IVM experimentation.

Combination of Fluorescence-Guided Surgery With Photodynamic Therapy for the Treatment of Cancer

Specific visualization of body parts is needed during surgery. Fluorescence-guided surgery (FGS) uses a fluorescence contrast agent for in vivo tumor imaging to detect and identify both malignant and normal tissues. There are several advantages and clinical benefits of FGS over other conventional medical imaging modalities, such as its safety, effectiveness, and suitability for real-time imaging in the operating room. Recent advancements in contrast agents and intraoperative fluorescence imaging devices have led to a greater potential for intraoperative fluorescence imaging in clinical applications. Photodynamic therapy (PDT) is an alternative modality to treat tumors, which uses a light-sensitive drug (photosensitizers) and special light to destroy the targeted tissues. In this review, we discuss the fluorescent contrast agents, some newly developed imaging devices, and the successful clinical application of FGS. Additionally, we present the combined strategy of FGS with PDT to further improve the therapeutic effect for patients with cancer. Taken together, this review provides a unique perspective and summarization of FGS.

Lymph Node Fluorescence During Robot-Assisted Radical Prostatectomy With Indocyanine Green: Prospective Dosing Analysis

OBJECTIVE

To prospectively assess the ideal dosing and the value of fluorescent sentinel lymph node (LN) detection with indocyanine green (ICG) for the detection of LN metastases in intermediate- and high-risk patients undergoing robot-assisted prostatectomy and extended pelvic LN dissection (ePLND).

PATIENTS AND METHODS

Twenty patients received transperineal prostatic injections of ICG. Patients were cycled through 5 doses (1.25, 2.5, 3.75, 5, and 7.5 mg) so optimal ICG dosing could be discovered early.

RESULTS

ICG injection was able to identify fluorescent LN (FLN) packets in all 20 patients. Compared to the higher ICG doses, the 1.25 and 2.5 mg doses had fewer FLN packets and were abandoned after 1 dose each. The median number of FLN packets was 4.0, 6.0, and 4.5 for the respective doses of 3.75, 5.0, and 7.5 mg. The external iliac group was the most common site of fluorescence in 27.2% of patients, followed by the common iliac (21.3%), obturator (20.3%), internal iliac (18.5%), and node of Cloquet (7.7%). Seven (35%) of 20 patients had node-positive disease. Of the 5 patients that had fluorescent tissue outside of our ePLND template, 1 had a positive node present in the anterior bladder neck fat. Across all patients, ICG had 62% sensitivity, 50% specificity, 8% positive predictive value, and 95% negative predictive value in detecting LN metastases.

CONCLUSION

The low sensitivity of ICG for the detection of LN metastases highlights why FLN dissection with ICG does not represent an alternative to ePLND.

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.

Multispectral Fluorescence Imaging During Robot-assisted Laparoscopic Sentinel Node Biopsy: A First Step Towards a Fluorescence-based Anatomic Roadmap

BACKGROUND

During (robot-assisted) sentinel node (SN) biopsy procedures, intraoperative fluorescence imaging can be used to enhance radioguided SN excision. For this combined pre- and intraoperative SN identification was realized using the hybrid SN tracer, indocyanine green-^99mTc-nanocolloid. Combining this dedicated SN tracer with a lymphangiographic tracer such as fluorescein may further enhance the accuracy of SN biopsy.

OBJECTIVE

Clinical evaluation of a multispectral fluorescence guided surgery approach using the dedicated SN tracer ICG-^99mTc-nanocolloid, the lymphangiographic tracer fluorescein, and a commercially available fluorescence laparoscope.

DESIGN, SETTING, AND PARTICIPANTS

Pilot study in ten patients with prostate cancer. Following ICG-^99mTc-nanocolloid administration and preoperative lymphoscintigraphy and single-photon emission computed tomograpy imaging, the number and location of SNs were determined. Fluorescein was injected intraprostatically immediately after the patient was anesthetized. A multispectral fluorescence laparoscope was used intraoperatively to identify both fluorescent signatures.

SURGICAL PROCEDURE

Multispectral fluorescence imaging during robot-assisted radical prostatectomy with extended pelvic lymph node dissection and SN biopsy.

MEASUREMENTS

(1) Number and location of preoperatively identified SNs. (2) Number and location of SNs intraoperatively identified via ICG-^99mTc-nanocolloid imaging. (3) Rate of intraoperative lymphatic duct identification via fluorescein imaging. (4) Tumor status of excised (sentinel) lymph node(s). (5) Postoperative complications and follow-up.

RESULTS AND LIMITATIONS

Near-infrared fluorescence imaging of ICG-^99mTc-nanocolloid visualized 85.3% of the SNs. In 8/10 patients, fluorescein imaging allowed bright and accurate identification of lymphatic ducts, although higher background staining and tracer washout were observed. The main limitation is the small patient population.

CONCLUSION

Our findings indicate that a lymphangiographic tracer can provide additional information during SN biopsy based on ICG-^99mTc-nanocolloid. The study suggests that multispectral fluorescence image-guided surgery is clinically feasible.

PATIENT SUMMARY

We evaluated the concept of surgical fluorescence guidance using differently colored dyes that visualize complementary features. In the future this concept may provide better guidance towards diseased tissue while sparing healthy tissue, and could thus improve functional and oncologic outcomes.

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.

Stone/tissue differentiation for holmium laser lithotripsy using autofluorescence

BACKGROUND AND OBJECTIVES

Holmium laser lithotripsy is a safe and effective method to disintegrate urinary stones of all compositions in an endoscopic procedure. However, handling and safety could be improved by a real-time feedback system permanently monitoring the position of the treatment fiber. The laser is fired only when the fiber is identified as being placed in front of stone. This work evaluates the potential of fluorescence detection with an excitation wavelength of 532 nm for this purpose.

MATERIALS AND METHODS

A fiber-based fluorescence measurement was set-up to acquire autofluorescence signals from several human renal calculi, artificial stones, and porcine tissue samples (renal calix and ureter). Three different approaches were investigated. First, experiments were performed with a pulsed laser source with a wavelength of 532 nm, pulse energy 36.5 ± 1 μJ, pulse duration 1.2 ± 0.5 nanoseconds, and a repetition rate of 1 kHz with 15 urinary concretions. In the second step, a series of measurements on 42 human urinary calculi samples was carried out using low power continuous wave excitation of 0.4 ± 0.1 mW. Fluorescence was also measured simultaneously to stone fragmentation by holmium laser pulses (pulse energy 240 ± 50 mJ, repetition rate 10 Hz). Finally, a modulated excitation/detection scheme (lock-in technique) was implemented to render fluorescence detection insensitive to white background light.

RESULTS

Unlike porcine renal calix, ureter, and artificial stone human urinary calculi show a strong fluorescence signal when excited with 532 nm. With pulsed excitation on urinary stone (20,000 ± 11,000) counts were registered at 587 nm with the CCD-array of a grating spectrometer in an integration time of 50 milliseconds. Tissue gave lower count rates of ≤(5,500 ± 1,100) even with longer integration times (500 milliseconds/1 second). With a cw excitation power of 0.4 mW (13,000 ± 11,000) counts were registered in an integration time of 200 milliseconds at 587 nm (porcine renal calix: (770 ± 340)). Modulated excitation (66 Hz) with an average power of 0.3 mW and detection with a photodiode resulted in a lock-in amplifier signal of 1.5-4.3V on stone (background and skin: <0.5V).

CONCLUSION

With the lock-in technique, autofluorescence from stones can be detected with only the average excitation power of a green aiming beam overlaid to the Ho:YAG-laser beam (power ≤ 1 mW). Since tissue shows very little autofluorescence when excited with 532 nm, this fluorescence signal enables monitoring of the correct position of the treatment fiber during ureteroscopic procedures.

Outcomes of robotic-assisted laparoscopic upper urinary tract reconstruction: 250 consecutive patients

OBJECTIVE

To evaluate the long-term outcomes of robotic-assisted laparoscopic (RAL) upper urinary tract (UUT) reconstruction performed at a tertiary referral centre.

MATERIALS AND METHODS

Data from 250 consecutive patients undergoing RAL UUT reconstruction, including pyeloplasty with or without stone extraction, ureterolysis, uretero-ureterostomy, ureterocalicostomy, ureteropyelostomy, ureteric reimplantation and buccal mucosa graft ureteroplasty, were collected at a tertiary referral centre between March 2003 and December 2013. The primary outcomes were symptomatic and radiographic improvement of obstruction and complication rate. The mean follow-up was 17.1 months.

RESULTS

Radiographic and symptomatic success rates ranged from 85% to 100% for each procedure, with a 98% radiographic success rate and 97% symptomatic success rate for the entire series. There were a total of 34 complications, none greater than Clavien grade 3.

CONCLUSION

Robotic-assisted laparoscopic UUT can be performed with few complications, with durable long-term success, and is a reasonable alternative to the open procedure in experienced robotic surgeons.

A novel method for intraoperative sentinel lymph node detection in prostate cancer patients using superparamagnetic iron oxide nanoparticles and a handheld magnetometer: the initial clinical experience

BACKGROUND

A sentinel lymph node (SLN) biopsy using superparamagnetic iron oxide nanoparticles (SPIOs) as a tracer instead of radioisotopes was first applied successfully in breast cancer. This study determined the feasibility of this new technique using SPIOs and a handheld magnetometer to detect SLNs in prostate cancer (PC).

METHODS

Enrolled 20 patients with intermediate and high-risk PC (PSA >10 and/or Gleason score >7) in a prospective study (12/2013-1/2014; DRKS00005473), following an ethics committee approval. After transrectal intraprostatic SPIOs injection a day earlier, patients (19/20) underwent magnetometer-guided sentinel lymphadenectomy (sPLND) and extended PLND, followed by radical prostatectomy. One patient was not operated because of an unrelated coagulation disorder. The ex vivo magnetic activity of all lymph nodes (LNs) removed was measured. The detection rate, rate of in vivo detected SLNs, and sensitivity of sPLND was established.

RESULTS

No adverse events attributable to SPIOs injection were observed. Identified 126 SLNs (median 7, IQR 4-9) and resected 334 LNs (median 17, IQR 14-19); 37 % (7/19) of the patients had LN metastases (median 1, IQR 1-3.5). The detection rate and rate of in vivo detected SLNs were 90 % (17/19) and 94 % (118/126) respectively. Using sPLND, all LN metastases were detected (15/15, sensitivity 100 %) in all patients identified with SLNs. One LN + patient showed no SLNs following transurethral prostate resection.

CONCLUSIONS

This is the first study using a magnetic tracer and magnetometer to detect SLNs in PC. Initial data indicate that this simple, radiation-free procedure is safe, feasible, and reliably identifies SLN and LN metastases in most patients.

Optimization of sentinel lymph node mapping in bladder cancer using near-infrared fluorescence imaging

BACKGROUND AND OBJECTIVES

Unlike other cancers, the Sentinel Lymph Node (SLN) procedure in bladder cancer requires special attention to the injection technique. The aim of this study was to assess feasibility and to optimize tracer injection technique for SLN mapping in bladder cancer patients using NIR fluorescence imaging.

METHODS

Twenty patients with invasive bladder cancer scheduled for radical cystectomy were prospectively enrolled. Indocyanine green (ICG) bound to human serum albumin (complex ICG:HSA; 500 µM) was injected peritumourally to permit SLN mapping. ICG:HSA was first administrated serosally (n = 5), and subsequently mucosally by cystoscopic injection (n = 15). In the last cohort of 12 patients treated with cystoscopic injection, the bladder was kept filled with saline for at least 15 min.

RESULTS

Fluorescent lymph nodes were observed only in the patient group with cystoscopic injection of ICG:HSA. Filling of the bladder post-injection was of added value to promote drainage of ICG:HSA to the lymph nodes, and in 11 of these 12 patients (92%) one or more NIR fluorescent lymph nodes were identified.

CONCLUSIONS

The current study demonstrates proof-of-principle of using NIR fluorescence imaging for SLN identification in bladder cancer. Cystoscopic injection with distension of the bladder appears optimal for SLN mapping.

Intraoperative optical imaging and tissue interrogation during urologic surgery

PURPOSE OF REVIEW

To review optical imaging technologies in urologic surgery aimed to facilitate intraoperative imaging and tissue interrogation.

RECENT FINDINGS

Emerging new optical imaging technologies can be integrated in the operating room environment during minimally invasive and open surgery. These technologies include macroscopic fluorescence imaging that provides contrast enhancement between normal and diseased tissue and microscopic imaging that provides tissue characterization.

SUMMARY

Optical imaging technologies that have reached the clinical arena in urologic surgery were reviewed, including photodynamic diagnosis, near infrared fluorescence imaging, optical coherence tomography, and confocal laser endomicroscopy.

A hybrid radioactive and fluorescent tracer for sentinel node biopsy in penile carcinoma as a potential replacement for blue dye

BACKGROUND

Sentinel node (SN) biopsy in penile cancer is typically performed using a combination of radiocolloid and blue dye. Recently, the hybrid radioactive and fluorescent tracer indocyanine green (ICG)-(99m)Tc-nanocolloid was developed to combine the beneficial properties of both radio-guidance and fluorescence imaging.

OBJECTIVE

To explore the added value of SN biopsy using ICG-(99m)Tc-nanocolloid in patients with penile carcinoma.

DESIGN, SETTING, AND PARTICIPANTS

Sixty-five patients with penile squamous cell carcinoma were prospectively included (January 2011 to December 2012). Preoperative SN mapping was performed using lymphoscintigraphy and single-proton emission computed tomography supplemented with computed tomography (SPECT/CT) after peritumoural injection of ICG-(99m)Tc-nanocolloid. During surgery, SNs were initially approached using a gamma probe, followed by patent blue dye and/or fluorescence imaging. A portable gamma camera was used to confirm excision of all SNs.

SURGICAL PROCEDURE

Patients underwent SN biopsy of the cN0 groin and treatment of the primary tumour.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

The number and location of preoperatively identified SNs were documented. Intraoperative SN identification rates using radio- and/or fluorescence guidance were assessed and compared with blue dye. Statistical evaluation was performed using a two-sample test for equality of proportions with continuity correction.

RESULTS AND LIMITATIONS

Preoperative imaging after injection of ICG-(99m)Tc-nanocolloid enabled SN identification in all patients (a total of 183 SNs dispersed over 119 groins). Intraoperatively, all SNs identified by preoperative SN mapping were localised using combined radio-, fluorescence-, and blue dye guidance. Fluorescence imaging enabled visualisation of 96.8% of SNs, while only 55.7% was stained by blue dye (p<0.0001). The tissue penetration of the fluorescent signal, and the rapid flow of blue dye limited the detection sensitivity. A tumour-positive SN was found in seven patients.

CONCLUSIONS

ICG-(99m)Tc-nanocolloid allows for both preoperative SN mapping and combined radio- and fluorescence-guided SN biopsy in penile carcinoma patients and significantly improves optical SN detection compared with blue dye.

Fluorescence-enhanced robotic radical prostatectomy using real-time lymphangiography and tissue marking with percutaneous injection of unconjugated indocyanine green: the initial clinical experience in 50 patients

BACKGROUND

Pilot studies have demonstrated the utility of indocyanine green (ICG) sentinel lymphadenectomy for prostate cancer. Prior work has used ICG with radiocontrast agents injected at a separate procedure and relied on assistant-controlled fluorescence systems, making the technique costly and cumbersome.

OBJECTIVE

To describe the initial optimization and feasibility of fluorescence-enhanced robotic radical prostatectomy (FERRP) using real-time injection of ICG for tissue marking and identification of sentinel lymphatic drainage visualized by a fully integrated surgeon-controlled system.

DESIGN, SETTING, AND PARTICIPANTS

Patients with clinically localized prostate cancer at a tertiary referral center were offered FERRP. Ten patients participated in a pilot arm in which ICG dosing and injection technique were optimized. Fifty consecutive patients then underwent FERRP.

SURGICAL PROCEDURE

After development of the space of Retzius, 0.4 ml of a 2.5 mg/ml ICG solution were injected into each lobe of the prostate using a robotically guided percutaneous needle. After ICG was allowed to travel through the pelvic lymphatics, lymphadenectomy was performed from the endopelvic fascia to the aortic bifurcation.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Parameters describing the time course of tissue fluorescence and pelvic lymphangiography were systematically recorded. Lymphatic packets containing fluorescent nodes were considered sentinel.

RESULTS AND LIMITATIONS

Percutaneous, robotic-guided ICG injection proved superior to cystoscope or transrectal delivery. Tissue marking was achieved in all patients, positively identifying the prostate with uniform fluorescence relative to the obturator nerve, seminal vesicles, vas deferens, and neurovascular pedicles at a mean time of 10 min postinjection. Sentinel nodes were identified in 76% of patients at a mean time of 30 min postinjection and had 100% sensitivity, 75.4% specificity, 14.6% positive predictive value, and 100% negative predictive value for the detection of nodal metastasis.

CONCLUSIONS

FERRP is safe, feasible, and allows for reliable prostate tissue marking and identification of sentinel lymphatic drainage in the majority of patients. ICG sentinel nodes are highly sensitive but relatively nonspecific for the detection of nodal metastasis.

Advances in Robotic-Assisted Radical Prostatectomy over Time

Since the introduction of robot-assisted radical prostatectomy (RALP), robotics has become increasingly more commonplace in the armamentarium of the urologic surgeon. Robotic utilization has exploded across surgical disciplines well beyond the fields of urology and prostate surgery. The literature detailing technical steps, comparison of large surgical series, and even robotically focused randomized control trials are available for review. RALP, the first robot-assisted surgical procedure to achieve widespread use, has recently become the primary approach for the surgical management of localized prostate cancer. As a result, surgeons are constantly trying to refine and improve upon current technical aspects of the operation. Recent areas of published modifications include bladder neck anastomosis and reconstruction, bladder drainage, nerve sparing approaches and techniques, and perioperative and postoperative management including penile rehabilitation. In this review, we summarize recent advances in perioperative management and surgical technique for RALP.

Near-infrared fluorescence imaging: emerging applications in robotic upper urinary tract surgery

BACKGROUND

Near-infrared fluorescence (NIRF) imaging is a technology with emerging applications in urologic surgery.

OBJECTIVE

To describe surgical techniques and provide clinical outcomes for robotic partial nephrectomy (RPN) with selective clamping and robotic upper urinary tract reconstruction featuring novel applications of NIRF imaging.

DESIGN, SETTING, AND PARTICIPANTS

Data from 90 patients who underwent successful RPN with selective clamping or upper urinary tract reconstruction utilizing NIRF imaging between April 2011 and October 2012 were reviewed.

SURGICAL PROCEDURE

We performed RPN utilizing NIRF imaging to aid with selective clamping and upper tract reconstruction with NIRF imaging, the details of which are outlined in this paper and the accompanying video.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Patient characteristics, perioperative outcomes, and complications were analyzed.

RESULTS AND LIMITATIONS

Of the 48 RPN patients for whom selective clamping was attempted successfully, median estimated blood loss was 200.0 ml, warm ischemia time was 17.0 min, and median change in estimated glomerular filtration rate was -6.3%. There was a 12.5% complication rate, and all complications were Clavien grade 1-3 (14.3%). The upper urinary tract reconstruction utilizing NIRF imaging was performed in 42 patients and included pyelopasty (n=20), ureteral reimplant (n=13), ureterolysis (n=7), and ureteroureterostomy (n=2). Radiographic and symptomatic improvement was observed in 100% of the pyeloplasty, ureteral reimplant, and ureteroureterostomy patients and 71.4% of ureterolysis patients, for an overall success rate of 95.2%. This study is limited by the small sample size, the short follow-up period, and the lack of a comparative cohort.

CONCLUSIONS

Our technique of RPN with selective arterial clamping and robotic upper urinary tract reconstruction utilizing NIRF imaging is presented. This technology provides real-time intraoperative angiogram to confirm selective ischemia and may be an adjunct technology to confirm well-perfused tissue within a reconstruction anastomosis. Further investigation is needed to evaluate long-term outcomes of NIRF imaging in robotic upper urinary tract surgery and to delineate its indications.

Fluorescein derivatives in intravital fluorescence imaging

Intravital fluorescence microscopy enables the direct imaging of fluorophores in vivo and advanced techniques such as fluorescence lifetime imaging (FLIM) enable the simultaneous detection of multiple fluorophores. Consequently, it is now possible to record distribution and metabolism of a chemical in vivo and to optimise the delivery of fluorophores in vivo. Recent clinical applications with fluorescein and other intravital fluorescent stains have occurred in neurosurgery, dermatology [including photodynamic therapy (PDT)] and endomicroscopy. Potential uses have been identified in periodontal disease, skin graft and cancer surgery. Animal studies have demonstrated that diseased tissue can be specifically stained with fluorophore conjugates. This review focuses on the fluorescein derived fluorophores in common clinical use and provides examples of novel applications from studies in tissue samples.

Clearance mechanism of protoporphyrin IX from mouse skin after application of 5-aminolevulinic acid

BACKGROUND

5-Aminolevulinic acid (ALA) or its esters mediated photodynamic therapy (PDT) is the most widely practiced form of PDT in dermatology. One of its advantages is that undesirable photosensitization lasts only for 24-48 h. In order to optimize ALA-PDT it is necessary to understand the mechanisms of intracellular production and clearance of PpIX (efflux from cells into blood stream and/or its conversion into haem). The aim of this study is to investigate the factors controlling the clearance of intracellular PpIX from healthy skin of mice.

METHODS

PpIX was induced in mouse skin by topical or systemic application of ALA or by topical application of the iron chelator ethylenediaminetetraacetic acid (EDTA). Fluorescence spectroscopy was used to study PpIX kinetics in alive and dead skin.

RESULTS

Topical application of ALA or EDTA leads to porphyrin production in living skin, but not in excised skin. The clearance rates of PpIX from alive and dead skin were the same in the absence of an intracellular ALA pool. The clearance half-life of EDTA-induced PpIX was 4-7 times longer than that of PpIX after application of ALA.

CONCLUSIONS

Skin temperature and intracellular iron availability strongly affect PpIX clearance, while ALA application mode (topical versus systemic) and skin viability (dead versus alive) have no influence on PpIX decay. These results demonstrate that the clearance kinetics of PpIX from skin are determined mostly by the conversion of PpIX into haem, while the cellular efflux of PpIX into blood plays a minor role.

Inherently multimodal nanoparticle-driven tracking and real-time delineation of orthotopic prostate tumors and micrometastases

Prostate cancer is the most common cancer among men and the second cause of male cancer-related deaths. There are currently three critical needs in prostate cancer imaging to personalize cancer treatment: (1) accurate intraprostatic imaging for multiple foci and extra-capsular extent; (2) monitoring local and systemic treatment response and predicting recurrence; and (3) more sensitive imaging of occult prostate cancer bone metastases. Recently, our lab developed porphysomes, inherently multimodal, all-organic nanoparticles with flexible and robust radiochemistry. Herein, we validate the first in vivo application of (64)Cu-porphysomes in clinically relevant orthotopic prostate and bony metastatic cancer models. We demonstrate clear multimodal delineation of orthotopic tumors on both the macro- and the microscopic scales (using both PET and fluorescence) and sensitively detected small bony metastases (<2 mm). The unique and multifaceted properties of porphysomes offers a promising all-in-one prostate cancer imaging agent for tumor detection and treatment response/recurrence monitoring using both radionuclide- and photonic-based strategies.

Clinical trial of combined radio- and fluorescence-guided sentinel lymph node biopsy in breast cancer

BACKGROUND

Combining radioactive colloids and a near-infrared (NIR) fluorophore permits preoperative planning and intraoperative localization of deeply located sentinel lymph nodes (SLNs) with direct optical guidance by a single lymphatic tracer. The aim of this clinical trial was to evaluate and optimize a hybrid NIR fluorescence and radioactive tracer for SLN detection in patients with breast cancer.

METHODS

Patients with breast cancer undergoing SLN biopsy were enrolled. The day before surgery, a periareolar injection of indocyanine green (ICG)-99mTc-radiolabelled nanocolloid was administered and a lymphoscintigram acquired. Blue dye was injected immediately before surgery. Intraoperative SLN localization was performed using a γ probe and the Mini-FLARE™ NIR fluorescence imaging system. Patients were divided into two dose groups, with one group receiving twice the particle density of ICG and nanocolloid, but the same dose of radioactive 99mTc.

RESULTS

Thirty-two patients were enrolled in the trial. At least one SLN was identified before and during operation. All 48 axillary SLNs could be detected by γ tracing and NIR fluorescence imaging, but only 42 of them stained blue. NIR fluorescence imaging permitted detection of lymphatic vessels draining to the SLN up to 29 h after injection. Doubling the particle density did not yield a difference in fluorescence intensity (median 255 (range 98-542) versus 284 (90-921) arbitrary units; P = 0.590) or signal-to-background ratio (median 5·4 (range 3·0-15·4) versus 4·9 (3·5-16·3); P = 1·000) of the SLN.

CONCLUSION

The hybrid NIR fluorescence and radioactive tracer permitted accurate preoperative and intraoperative detection of the SLNs in patients with breast cancer.

REGISTRATION NUMBER

NTR3685 (Netherlands Trial Register; http://www.trialregister.nl).