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.

Real-time intraoperative detection of breast cancer using near-infrared fluorescence imaging and Methylene Blue.

BACKGROUND: Despite recent developments in preoperative breast cancer imaging, intraoperative localization of tumor tissue can be challenging, resulting in tumor-positive resection margins during breast conserving surgery. Based on certain physicochemical similarities between Technetium((99m)Tc)-sestamibi (MIBI), an SPECT radiodiagnostic with a sensitivity of 83-90% to detect breast cancer preoperatively, and the near-infrared (NIR) fluorophore Methylene Blue (MB), we hypothesized that MB might detect breast cancer intraoperatively using NIR fluorescence imaging. METHODS: Twenty-four patients with breast cancer, planned for surgical resection, were included. Patients were divided in 2 administration groups, which differed with respect to the timing of MB administration. N = 12 patients per group were administered 1.0 mg/kg MB intravenously either immediately or 3 h before surgery. The mini-FLARE imaging system was used to identify the NIR fluorescent signal during surgery and on post-resected specimens transferred to the pathology department. Results were confirmed by NIR fluorescence microscopy. RESULTS: 20/24 (83%) of breast tumors (carcinoma in N = 21 and ductal carcinoma in situ in N = 3) were identified in the resected specimen using NIR fluorescence imaging. Patients with non-detectable tumors were significantly older. No significant relation to receptor status or tumor grade was seen. Overall tumor-to-background ratio (TBR) was 2.4 ± 0.8. There was no significant difference between TBR and background signal between administration groups. In 2/4 patients with positive resection margins, breast cancer tissue identified in the wound bed during surgery would have changed surgical management. Histology confirmed the concordance of fluorescence signal and tumor tissue. CONCLUSIONS: This feasibility study demonstrated an overall breast cancer identification rate using MB of 83%, with real-time intraoperative guidance having the potential to alter patient management.

Intraoperative fluorescence delineation of head and neck cancer with a fluorescent anti-epidermal growth factor receptor nanobody.

Intraoperative near-infrared (NIR) fluorescence imaging is a technology with high potential to provide the surgeon with real-time visualization of tumors during surgery. Our study explores the feasibility for clinical translation of an epidermal growth factor receptor (EGFR)-targeting nanobody for intraoperative imaging and resection of orthotopic tongue tumors and cervical lymph node metastases. The anti-EGFR nanobody 7D12 and the negative control nanobody R2 were conjugated to the NIR fluorophore IRDye800CW (7D12-800CW and R2-800CW). Orthotopic tongue tumors were induced in nude mice using the OSC-19-luc2-cGFP cell line. Tumor-bearing mice were injected with 25 µg 7D12-800CW, R2-800CW or 11 µg 800CW. Subsequently, other mice were injected with 50 or 75 µg of 7D12-800CW. The FLARE imaging system and the IVIS spectrum were used to identify, delineate and resect the primary tumor and cervical lymph node metastases. All tumors could be clearly identified using 7D12-800CW. A significantly higher tumor-to-background ratio (TBR) was observed in mice injected with 7D12-800CW compared to mice injected with R2-800CW and 800CW. The highest average TBR (2.00 ± 0.34 and 2.72 ± 0.17 for FLARE and IVIS spectrum, respectively) was observed 24 hr after administration of the EGFR-specific nanobody. After injection of 75 µg 7D12-800CW cervical lymph node metastases could be clearly detected. Orthotopic tongue tumors and cervical lymph node metastases in a mouse model were clearly identified intraoperatively using a recently developed fluorescent EGFR-targeting nanobody. Translation of this approach to the clinic would potentially improve the rate of radical surgical resections.

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).

Near-infrared fluorescence sentinel lymph node biopsy in vulvar cancer: a randomised comparison of lymphatic tracers.

This study aims to confirm the feasibility of near-infrared (NIR) fluorescence imaging for sentinel lymph node (SLN) biopsy in vulvar cancer and to compare the tracer indocyanine green (ICG) bound to human serum albumin (HSA) versus ICG alone. Women received 99mTc-nanocolloid and patent blue for SLN detection. Subsequently, women randomly received ICG:HSA or ICG alone. In 24 women, 35 SLNs were intraoperatively detected. All SLNs detected were radioactive and NIR fluorescent and 27 (77%) were blue. No significant difference was found between ICG:HSA and ICG alone. This trial confirms the feasibility of NIR fluorescence imaging for SLN mapping in vulvar cancer.

Dose optimization for near-infrared fluorescence sentinel lymph node mapping in patients with melanoma.

BACKGROUND: Regional lymph node involvement is the most important prognostic factor in cutaneous melanoma. As only 20% of patients with melanoma have occult nodal disease and would benefit from a regional lymphadenectomy, the sentinel lymph node (SLN) biopsy was introduced. Near-infrared (NIR) fluorescence has been hypothesized to improve SLN mapping. OBJECTIVES: To assess the potential of intraoperative NIR fluorescence imaging to improve SLN mapping in patients with melanoma and to examine the optimal dose of indocyanine green adsorbed to human serum albumin (ICG:HSA). METHODS: Fifteen consecutive patients with cutaneous melanoma underwent the standard SLN procedure using (99m) technetium-nancolloid and patent blue. In addition, intraoperative NIR fluorescence imaging was performed after injection of 1·6 mL of 600, 800, 1000 or 1200 µmolL(-1) of ICG: HSA in four quadrants around the primary excision scar. RESULTS: NIR fluorescence SLN mapping was successful in 93% of patients. In one patient, no SLN could be identified using either conventional methods or NIR fluorescence. A total of 30 SLNs (average 2·0, range 1-7) were detected, 30 radioactive (100%), 27 blue (73%) and 30 NIR fluorescent (100%). With regard to the effect of concentration on signal-to-background ratios a trend (P=0·066) was found favouring the 600, 800 and 1000 µmol L(-1) groups over the 1200 µmol L(-1) group. CONCLUSION: This study demonstrates feasibility and accuracy of SLN mapping using ICG: HSA. Considering safety, cost and pharmacological characteristics, an ICG: HSA concentration of 600 µmolL(-1) appears optimal for SLN mapping in cutaneous melanoma, although lower doses need to be assessed.