ICG fluorescence-guided sentinel node biopsy for axillary nodal staging in breast cancer

Transcutaneous detection and direct approach to the sentinel node using axillary compression technique in ICG fluorescence-navigated sentinel node biopsy for breast cancer

BACKGROUND

Indocyanine green (ICG) fluorescence navigation is a useful option in sentinel node biopsy (SNB) for breast cancer. However, several technical difficulties still exist. Since the sentinel node (SN) cannot be recognized over the skin, subcutaneous lymphatic vessels (LVs) must be carefully dissected without injury. In addition, the dissecting procedures are often interrupted by turning off the operating light during fluorescence observation. In this report, we introduce a new approach using the axillary compression technique to overcome these problems.

MATERIALS AND METHODS

In the original procedure of the ICG fluorescence method, the subcutaneous lymphatic drainage pathway from the breast to the axilla was observed in fluorescence images, but no signal could be obtained in the axilla. When the axillary skin was compressed against the chest wall using a plastic device, the signals from the deeper lymphatic structures could be observed. By tracing the compression-inducible fluorescence signal towards the axilla, transcutaneous detection and direct approach to the SN were achieved. The benefit of this approach is that there is no risk of injury of LVs, and the procedures are interrupted less frequently by fluorescence observation. The axillary compression technique was used in 50 patients with early breast cancer.

RESULTS

SNs were successfully removed in all patients. Transcutaneous detection and direct approach were possible in 47 patients. This approach was also effective in obese patients.

CONCLUSIONS

Axillary compression technique is a simple way to facilitate the surgical procedures of ICG fluorescence-navigated SNB for breast cancer.

Randomized, double-blind comparison of indocyanine green with or without albumin premixing for near-infrared fluorescence imaging of sentinel lymph nodes in breast cancer patients

Near-infrared (NIR) fluorescence imaging has the potential to improve sentinel lymph node (SLN) mapping in breast cancer. Indocyanine green (ICG) is currently the only clinically available fluorophore that can be used for SLN mapping. Preclinically, ICG adsorbed to human serum albumin (ICG:HSA) improves its performance as a lymphatic tracer in some anatomical sites. The benefit of ICG:HSA for SLN mapping of breast cancer has not yet been assessed in a clinical trial. We performed a double-blind, randomized study to determine if ICG:HSA has advantages over ICG alone. The primary endpoint was the fluorescence brightness, defined as the signal-to-background ratio (SBR), of identified SLNs. Clinical trial subjects were 18 consecutive breast cancer patients scheduled to undergo SLN biopsy. All patients received standard of care using (99m)Technetium-nanocolloid and patent blue. Patients were randomly assigned to receive 1.6 ml of 500 μM ICG:HSA or ICG that was injected periareolarly directly after patent blue. The Mini-Fluorescence-Assisted Resection and Exploration (Mini-FLARE) imaging system was used for NIR fluorescence detection and quantitation. SLN mapping was successful in all patients. Patient, tumor, and treatment characteristics were equally distributed over the treatment groups. No significant difference was found in SBR between the ICG:HSA group and the ICG alone group (8.4 vs. 11.3, respectively, P = 0.18). In both groups, the average number of detected SLNs was 1.4 ± 0.5 SLNs per patient (P = 0.74). This study shows that there is no direct benefit of premixing ICG with HSA prior to injection for SLN mapping in breast cancer patients, thereby reducing the cost and complexity of the procedure. With these optimized parameters that eliminate the necessity of HSA, larger trials can now be performed to determine patient benefit.

Current trends and emerging future of indocyanine green usage in surgery and oncology: a literature review

Ever since Kitai first performed fluorescent navigation of sentinel lymph nodes (SLNs) using indocyanine green (ICG) dye with a charge-couple device and light emitting diodes, the intraoperative use of near infrared fluorescence has served a critical role in increasing our understanding in various fields of surgical oncology. Here the authors review the emerging role of the ICG fluorophore in the development of our comprehension of the lymphatic system and its use in SLN mapping and biopsy in various cancers. In addition, they introduce the novel role of ICG-guided video angiography as a new intraoperative method of assessing microvascular circulation. The authors attempt to discuss the promising potential in addition to assessing several challenges and limitations in the context of specific surgical procedures and ICG as a whole. PubMed and Medline literature databases were searched for ICG use in clinical surgical settings. Despite ICG's significant impact in various fields of surgical oncology, ICG is still in its nascent stages, and more in-depth studies need to be carried out to fully evaluate its potential and limitations.

Sentinel node biopsy in breast cancer using infrared laser system first experience with PDE camera

BACKGROUND

Sentinel node biopsy (SNB) is a gold standard in staging of early breast cancer. Nowadays, routine mapping of lymphatic tract is based on two tracers: human albumin with radioactive technetium, with or without blue dye. Recent years have seen a search for new tracers to examine sentinel node as well as lymphatic network. One of them is indocyanine green (ICG) visible in infrared light.

AIM

The aim of this study is to evaluate clinical usage of ICG in comparison with standard tracer, i.e. nanocoll, in SNB of breast cancer patients.

MATERIALS AND METHODS

In the 1st Department of Surgical Oncology and General Surgery, Greater Poland Cancer Centre, Poznań, 13 female breast cancer patients have benn operated since September 2010. All these patients had sentinel node biopsy with nanocoll (human albumin with radioactive technetium), and with indocyanine green. The feasibility of this new method was assessed in comparison with the standard nanocoll.

RESULTS

A lymphatic network between the place of injection of ICG and sentinel node was seen in infrared light. An area where a sentinel node was possibly located was confirmed by gamma probe. Sensitivity of this method was 100%.

CONCLUSION

SNB using ICG is a new, promising diagnostics technique. This procedure is not without drawbacks; nevertheless it opens new horizons in lymphatic network diagnostics.

Toward optimization of imaging system and lymphatic tracer for near-infrared fluorescent sentinel lymph node mapping in breast cancer

Background

Near-infrared (NIR) fluorescent sentinel lymph node (SLN) mapping in breast cancer requires optimized imaging systems and lymphatic tracers.

Materials and Methods

A small, portable version of the FLARE imaging system, termed Mini-FLARE, was developed for capturing color video and two semi-independent channels of NIR fluorescence (700 and 800 nm) in real time. Initial optimization of lymphatic tracer dose was performed using 35-kg Yorkshire pigs and a 6-patient pilot clinical trial. More refined optimization was performed in 24 consecutive breast cancer patients. All patients received the standard of care using ^99mTechnetium-nanocolloid and patent blue. In addition, 1.6 ml of indocyanine green adsorbed to human serum albumin (ICG:HSA) was injected directly after patent blue at the same location. Patients were allocated to 1 of 8 escalating ICG:HSA concentration groups from 50 to 1000 μM.

Results

The Mini-FLARE system was positioned easily in the operating room and could be used up to 13 in. from the patient. Mini-FLARE enabled visualization of lymphatic channels and SLNs in all patients. A total of 35 SLNs (mean = 1.45, range 1–3) were detected: 35 radioactive (100%), 30 blue (86%), and 35 NIR fluorescent (100%). Contrast agent quenching at the injection site and dilution within lymphatic channels were major contributors to signal strength of the SLN. Optimal injection dose of ICG:HSA ranged between 400 and 800 μM. No adverse reactions were observed.

Conclusions

We describe the clinical translation of a new NIR fluorescence imaging system and define the optimal ICG:HSA dose range for SLN mapping in breast cancer.

Electronic supplementary material

The online version of this article (doi:10.1245/s10434-011-1566-x) contains supplementary material, which is available to authorized users.

Feasibility of ICG fluorescence-guided sentinel node biopsy in animal models using the HyperEye Medical System

BACKGROUND

The sentinel lymph node (SLN) concept is accepted for several types of cancers. Current methods for sentinel node detection involve radioisotopes and blue dye. They have shown good results, but some drawbacks remain. Indocyanine green (ICG) fluorescence using the HyperEye Medical System (HEMS) was evaluated as a new method.

METHODS

This was a prospective, nonrandomized, experimental study in four Japanese white rabbits and six Yorkshire pigs. ICG and indigo carmine were injected into the tongue, larynx, or hypopharynx, and ICG fluorescence detection was evaluated using both transcutaneous visualization of lymphatic vessels and intraoperative identification of SLNs.

RESULTS

The SLNs appeared as shining fluorescent spots with HEMS transcutaneously in rabbits, but no SLNs were detected transcutaneously in pigs. Eleven procedures identified SLNs, but one did not due to a technical problem.

CONCLUSIONS

HEMS could become useful for predicting lymph node metastasis during surgery for head and neck cancer.

Noninvasive photoacoustic and fluorescence sentinel lymph node identification using dye-loaded perfluorocarbon nanoparticles

The contrast mechanisms used for photoacoustic tomography (PAT) and fluorescence imaging differ in subtle, but significant, ways. The design of contrast agents for each or both modalities requires an understanding of the spectral characteristics as well as intra- and intermolecular interactions that occur during formulation. We found that fluorescence quenching that occurs in the formulation of near-infrared (NIR) fluorescent dyes in nanoparticles results in enhanced contrast for PAT. The ability of the new PAT method to utilize strongly absorbing chromophores for signal generation allowed us to convert a highly fluorescent dye into an exceptionally high PA contrast material. Spectroscopic characterization of the developed NIR dye-loaded perfluorocarbon-based nanoparticles for combined fluorescence and PA imaging revealed distinct dye-dependent photophysical behavior. We demonstrate that the enhanced contrast allows detection of regional lymph nodes of rats in vivo with time-domain optical and photoacoustic imaging methods. The results further show that the use of fluorescence lifetime imaging, which is less dependent on fluorescence intensity, provides a strategic approach to bridge the disparate contrast reporting mechanisms of fluorescence and PA imaging methods.

Intraoperative near-infrared fluorescence imaging for sentinel lymph node detection in vulvar cancer: first clinical results

OBJECTIVE

Disadvantages of the combined sentinel lymph node (SLN) procedure with radiocolloid and blue dye in vulvar cancer are the preoperative injections of radioactive tracer in the vulva, posing a painful burden on the patient. Intraoperative transcutaneous imaging of a peritumorally injected fluorescent tracer may lead to a one-step procedure, while maintaining high sensitivity. Aim of this pilot study was to investigate the applicability of intraoperative fluorescence imaging for SLN detection and transcutaneous lymphatic mapping in vulvar cancer.

METHODS

Ten patients with early stage squamous cell carcinoma of the vulva underwent the standard SLN procedure. Additionally, a mixture of 1 mL patent blue and 1 mL indocyanin green (ICG; 0.5 mg/mL) was injected immediately prior to surgery, with the patient under anesthesia. Color and fluorescence images and videos of lymph flow were acquired using a custom-made intraoperative fluorescence camera system. The distance between skin and femoral artery was determined on preoperative CT-scan as a measure for subcutaneous adipose tissue.

RESULTS

In 10 patients, SLNs were detected in 16 groins (4 unilateral; 6 midline tumors). Transcutaneous lymphatic mapping was possible in five patients (5 of 16 groins), and was limited to lean patients, with a maximal distance between femoral artery and skin of 24 mm, as determined on CT. In total, 29 SLNs were detected by radiocolloid, of which 26 were also detected by fluorescence and 21 were blue.

CONCLUSIONS

These first clinical results indicate that intraoperative transcutaneous lymphatic mapping using fluorescence is technically feasible in a subgroup of lean vulvar cancer patients.

Sentinel lymph node detection by an optical method using scattered photons

We present a new near infrared optical probe for the sentinel lymph node detection, based on the recording of scattered photons. A two wavelengths setup was developed to improve the detection threshold of an injected dye: the Patent Blue V dye. The method used consists in modulating each laser diode at a given frequency. A Fast Fourier Transform of the recorded signal separates both components. The signal amplitudes are used to compute relative Patent Blue V concentration. Results on the probe using phantoms model and small animal experimentation exhibit a sensitivity threshold of 3.2 µmol/L, which is thirty fold better than the eye visible threshold.

Image-guided tumor resection using real-time near-infrared fluorescence in a syngeneic rat model of primary breast cancer

Tumor involvement of resection margins is found in a large proportion of patients who undergo breast-conserving surgery. Near-infrared (NIR) fluorescence imaging is an experimental technique to visualize cancer cells during surgery. To determine the accuracy of real-time NIR fluorescence imaging in obtaining tumor-free resection margins, a protease-activatable NIR fluorescence probe and an intraoperative camera system were used in the EMR86 orthotopic syngeneic breast cancer rat model. Influence of concentration, timing and number of tumor cells were tested in the MCR86 rat breast cancer cell line. These variables were significantly associated with NIR fluorescence probe activation. Dosing and tumor size were also significantly associated with fluorescence intensity in the EMR86 rat model, whereas time of imaging was not. Real-time NIR fluorescence guidance of tumor resection resulted in a complete resection of 17 out of 17 tumors with minimal excision of normal healthy tissue (mean minimum and a mean maximum tumor-free margin of 0.2 ± 0.2 mm and 1.3 ± 0.6 mm, respectively). Moreover, the technique enabled identification of remnant tumor tissue in the surgical cavity. Histological analysis revealed that the NIR fluorescence signal was highest at the invasive tumor border and in the stromal compartment of the tumor. In conclusion, NIR fluorescence detection of breast tumor margins was successful in a rat model. This study suggests that clinical introduction of intraoperative NIR fluorescence imaging has the potential to increase the number of complete tumor resections in breast cancer patients undergoing breast-conserving surgery.

Sentinel node biopsy by indocyanine green retention fluorescence detection for inguinal lymph node staging of anal cancer: preliminary experience

BACKGROUND

There is some evidence that sentinel lymph node (SLN) biopsy guided by dye injection and/or radioisotopes can improve staging of inguinal lymph nodes (LNs) in anal cancer. This study was performed to investigate the feasibility of fluorescence detection of SLN and lymphatic mapping in anal cancer.

METHODS

Twelve patients with anal cancer without evidence for inguinal LN involvement were included in the study. Intraoperatively, all patients received a peritumorous injection of 25 mg indocyanine green (ICG) for fluorescence imaging of the SLN with a near-infrared camera. For comparison, conventional SLN detection by technetium-(99)m-sulfur radiocolloid injection in combination with blue dye was also performed in all patients. The results of both techniques and the effect on the therapeutic regimen were analyzed.

RESULTS

Overall, ICG fluorescence imaging identified at least one SLN in 10 of 12 patients (detection rate, 83%). With the combination of radionuclide and blue dye, SLN were detected in 9 of 12 patients (detection rate, 75%). Metastatic involvement of the SLN was found in 2 of 10 patients versus 2 of 9 patients. Patients with metastatic involvement of the SLN received extended radiation field with inguinal boost.

CONCLUSIONS

ICG fluorescence imaging allows intraoperative lymphatic mapping and transcutaneous SLN detection for selective biopsy of inguinal SLN in anal cancer. This technique should be further evaluated in comparative studies with larger patient numbers.