Diagnostic Performance of Indocyanine Green Plus Methylene Blue Versus Radioisotope Plus Methylene Blue Dye Method for Sentinel Lymph Node Biopsy in Node-Negative Early Breast Cancer

Indocyanine green fluorescence versus blue dye, technetium-99M, and the dual-marker combination of technetium-99M + blue dye for sentinel lymph node detection in early breast cancer-meta-analysis including consistency analysis

BACKGROUND

Axillary sentinel lymph node biopsies are standard of care in patients with breast cancer and no clinically apparent metastases. Traditionally, technetium-99m, blue dye, or both have been used to identify sentinel lymph nodes. However, blue dyes miss up to 40% of sentinel lymph nodes, while technetium-99m use is complex, costly, and exposes patients to radiation. Over the past decade, studies have consistently found the biologically inert fluorescent indocyanine green to be 95% to 100% sensitive in detecting breast cancer sentinel lymph nodes, yet indocyanine green remains infrequently used.

METHODS

We conducted an extensive meta-analysis comparing indocyanine green against blue dye, technetium-99m, and the dual-marker combination of technetium-99m + BD. Unlike prior meta-analyses that only assessed either per-case or per-node sentinel lymph node detection, we analyzed the following 5 metrics: per-case and per-node sentinel lymph node detection and metastasis-positive sentinel lymph node sensitivity, and mean number of sentinel lymph nodes/case. We further examined the consistency and magnitude of between-study superiority and statistically significant within-study superiority of each marker against others.

RESULTS

For every metric and analysis approach, indocyanine green was clearly superior to blue dye and at least non-inferior, if not superior, to technetium-99m and technetium-99m + blue dye. Assessing the consistency of superiority by at least 2.0%, indocyanine green was superior to blue dye 73 times versus 1, to technetium-99m 42 times versus 9, and to technetium-99m + blue dye 6 times versus 0. Within-study statistically significant differences favored indocyanine green over blue dye 29 times versus 0 and over technetium-99m 11 times versus 2.

DISCUSSION

For sentinel lymph node detection in patients with breast cancer with no clinically apparent metastases, indocyanine green is clearly and consistently superior to blue dye and either non-inferior or superior to technetium-99m and technetium-99m + blue dye.

Determining Accurate Dye Combinations for Sentinel Lymph Node Detection: A Systematic Review

Background

Lymphatic dyes are commonly used to map the drainage path from tumor to lymphatics, which are biopsied to determine if spread has occurred. A blue dye in combination with technetium-99 is considered the gold standard for mapping, although many other dyes and dye combinations are used. Not all of these substances have the same detection efficacy.

Methods

A systematic review of PubMed, SCOPUS, Web of Science, and Medline was performed. The predefined search terms were (indocyanine green OR isosulfan blue OR lymphazurin OR patent blue OR methylene blue OR fluorescein OR technetium-99) AND combination AND dye AND (sentinel lymph node biopsy OR lymphedema OR lymphatics OR lymph OR microsurgery OR cancer OR tumor OR melanoma OR carcinoma OR sarcoma).

Results

The initial search returned 4267 articles. From these studies, 37 were selected as candidates that met inclusion criteria. After a full-text review, 34 studies were selected for inclusion. Eighty-nine methods of sentinel lymph node (SLN) detection were trialed using 22 unique dyes, dye combinations, or other tracers. In total, 12,157 SLNs of 12,801 SLNs were identified. Dye accuracy ranged from 100% to 69.8% detection. Five dye combinations had 100% accuracy. Dye combinations were more accurate than single dyes.

Conclusions

Combining lymphatic dyes improves SLN detection results. Replacing technetium-99 with ICG may allow for increased access to SLN procedures with comparable results. The ideal SLN tracer is a low-cost molecule with a high affinity for lymphatic vessels due to size and chemical composition, visualization without specialized equipment, and no adverse effects.

Nano-tracers for sentinel lymph node detection: current trends in technique and application

Sentinel lymph node (SLN) detection and biopsy is a critical staging component for several cancers. Apart from established methods using dyes or radiolabeled colloids, newer techniques are emerging, like near-infrared fluorescent compounds, targeted molecular radiopharmaceuticals and magnetic nano-tracers. In the overview section of this review, we categorize SLN detection tracers based on their principle of use. We discuss the merits of existing tracers and provide a glimpse of in-development formulations. A subsequent clinical section explores the expanded role of SLN detection in management of various cancers, citing current medical guidelines and the leading conclusions of long-term clinical trials. The concluding section tries to provide a perspective of promising developments and the work required to bring them to clinical fruition.

Evaluation of learning curve with Indocyanine Green (IcG) versus blue dye for sentinel lymph node biopsy in breast cancer

BACKGROUND

Indocyanine green (IcG) is an alternative to isosulfan blue (IB) for sentinel lymph node (SLN) mapping in breast cancer (BC). IcG carries improved cost and safety, but oncologic data upon implementation in practice is limited. We evaluated the learning curve defined as oncologic yield and operative (OR) time for IcG in SLN mapping in BC.

METHODS

Retrospective review of patients >18 years with cTis-2 cN0 BC undergoing surgery first with SLN biopsy using IB or IcG. Analysis compared IB versus IcG across three time cohorts.

RESULTS

Of 278 patients, 77 received IB and 201 received IcG. OR time was longer for IcG (p ​= ​0.022). There was no difference in oncologic yield between groups (p ​= ​0.35, p ​= ​0.61).

CONCLUSIONS

Surgeons may be able to safely transition from IB to IcG for patients with early-stage breast cancer undergoing surgery first. Individuals should track their own data to confirm safety of the technique.

An Updated Review on the Emerging Role of Indocyanine Green (ICG) as a Sentinel Lymph Node Tracer in Breast Cancer

Sentinel lymph node biopsy (SLNB) has become the standard of care for clinically node-negative breast cancer and has recently been shown by clinical trials to be also feasible for clinically node-positive patients treated with primary systemic therapy. The dual technique using both radioisotope (RI) and blue dye (BD) as tracers for the identification of sentinel lymph nodes is considered the gold standard. However, allergic reactions to blue dye as well as logistics issues related to the use of radioactive agents, have led to research on new sentinel lymph node (SLN) tracers and to the development and introduction of novel techniques in the clinical practice. Indocyanine green (ICG) is a water-soluble dye with fluorescent properties in the near-infrared (NIR) spectrum. ICG has been shown to be safe and effective as a tracer during SLNB for breast cancer and accumulating evidence suggests that ICG is superior to BD and at least comparable to RI alone and to RI combined with BD. Thus, ICG was recently proposed as a reliable SLN tracer in some breast cancer clinical practice guidelines. Nevertheless, there is lack of consensus regarding the optimal role of ICG for SLN mapping. Specifically, it is yet to be determined whether ICG should be used in addition to BD and/or RI, or if ICG could potentially replace these long-established traditional SLN tracers. This article is an updated overview of somerecent studies that compared ICG with BD and/or RI regarding their accuracy and effectiveness during SLNB for breast cancer.

Comparison of Sentinel Lymph Node Biopsy by Blue Dye Conjunction With Indocyanine Green or Radioisotope in Early-Stage Breast Cancer: A Prospective Single-Center Observational Study

Background

Although radioisotope (RI) combined with blue dye (BD) is the standard technique for sentinel lymph node (SLN) biopsy in breast cancer, the use of RI is limited at some institutions due to the specific equipment needed. Indocyanine green (ICG) fluorescence detection has been developed as a potential substitute for RI method. However, reports on the sensitivity of ICG and RI techniques in detecting SLN are inconsistent; hence, the present study was designed to compare the clinical efficacy between the combined method of ICG + BD (ICG-B) and RI + BD (RI-B).

Methods

A prospective observational study was performed that identified 138 breast cancer patients who had undergone lymphatic mapping and SLN biopsy with ICG-B or RI-B. The SLN detection rate, positive SLN counts, and lymph node metastasis between the 2 groups were compared.

Results

A total of 71 patients were recruited in the ICG-B group, while 67 were recruited in the RI-B group. The SLN detection rate was 100% in both the ICG-B and RI-B groups. Lymph node metastasis was found in 13 patients using ICG-B and in 12 patients using the RI-B technique (18.31% vs 17.91%, respectively; P = .61). No significant differences were observed in the positive SLN counts (3.12 ± 2.01 vs 3.33 ± 2.24, P = .37) between the 2 groups.

Conclusions

Indocyanine green combined with BD has an equal efficacy compared with RI plus BD when performing an axillary SLN biopsy in breast cancer. The ICG plus BD procedure is a promising alternative to traditional standard mapping methods.

New techniques versus standard mapping for sentinel lymph node biopsy in breast cancer: a systematic review and meta-analysis

New tracers for sentinel lymph node biopsy (SLNB), as indocyanine green (ICG), superparamagnetic iron oxide (SPIO) and micro bubbles, have been recently introduced in clinical practice showing promising but variable results. We reviewed the available evidence comparing these new techniques with the standard tracers to evaluate their safety. To identify all available studies, a systematic search was performed in all electronic databases. Data regarding sample size, mean number of SLN harvested for patient, number of metastatic SLN and SLN identification rate of all studies were extracted. No significant differences were found in terms of SLNs identification rates between SPIO, RI and BD but with a higher identification rate with the use of ICG. No significant differences were also found for the number of metastatic lymph nodes identified between SPIO, RI and BD and the mean number of SLNs identified between SPIO and ICG versus conventional tracers. A statistically significant differences in favor of ICG was reported for the comparison between ICG and conventional tracers for the number of metastatic lymph nodes identified. Our meta-analysis demonstrates that the use of both ICG and SPIO for the pre-operative mapping of sentinel lymph nodes in breast cancer treatment is adequately effective.

Evaluation of Dual Dye Technique for Sentinel Lymph Node Biopsy in Breast Cancer: Two-Arm Open-Label Parallel Design Non-Inferiority Randomized Controlled Trial

INTRODUCTION

Radioisotope and blue dye are standard agents for performing sentinel lymph node (SLN) biopsy in breast cancer. The paucity of nuclear medicine facility poses logistic challenge. This study evaluated performance of radioisotope & methylene blue (MB) with indocyanine green (ICG) and MB for SLNB.

PATIENTS AND METHODS

This randomized controlled trial was conducted from December 2019 to July 2022 comparing SLN identification proportions of radioisotope-blue dye [Group A] with dual dye (MB + ICG; Group B]. Secondary objective included time required and cost effectiveness of performing SLNB. Sample size of 70 (35 in each arm) was calculated. Upfront operable node negative early breast cancer was included in the study. Clinico-demographic data, number & type of SLN, time taken were noted. Cost analysis was done including the equipment, manpower & consumables. Chi-square/Fisher exact test was used to compare proportion between two groups. p value of less than 0.05 was considered to represent statistical significance.

RESULTS

Seventy patients randomized to either group were similar in clinico-demographic and tumor characteristics. SLN identification rate (IR) was 91.43% in group A and 100% in group B. Overall IR of MB, radioisotope and ICG were 91.43%, 91.43% and 100%, respectively. Mean number of SLNs identified were 3 in group A and 4 in group B. Median time required for SLNB was 12 min and 14 min in either group, respectively. Cost of performing SLNB was higher in Group B.

CONCLUSION

SLNB using dual dye is non-inferior to radioisotope-blue dye in upfront operable early breast cancer. Trial registration number Clinical Trial registry India CTRI/2020/02/023503.

Indocyanine green combined with methylene blue versus methylene blue alone for sentinel lymph node biopsy in breast cancer: a retrospective study

BACKGROUND

Recent studies have shown that near-infrared (NIR) fluorescence imaging using Indocyanine green (ICG) may improve the efficiency of sentinel lymph node biopsy (SLNB). This study aimed to assess the effectiveness of the combination of ICG and methylene blue (MB) in breast cancer patients undergoing SLNB.

PATIENTS AND METHOD

We evaluated ICG plus MB (ICG + MB) identification effectiveness with MB alone using retrospective analysis. From 2016 to 2020, we collected data on 300 eligible breast cancer patients who got SLNB treatment in our institution by ICG + MB or MB alone. By comparing the distribution of clinicopathological characteristics, the detection rate of sentinel lymph nodes (SLNs) and metastatic SLNs, as well as the total number of SLNs in the two groups, we were able to assess the imaging efficiency.

RESULTS

Fluorescence imaging allowed 131 out of 136 patients in the ICG + MB group to find SLNs. ICG + MB group and MB group had detection rates of 98.5% and 91.5% (P = 0.007, χ² = 7.352), respectively. Besides, the ICG + MB approach was able to produce improved recognition outcomes. What's more, compared with the MB group, the ICG + MB group can identify more lymph nodes (LNs) (3.1 to 2.6, P = 0.000, t = 4.447). Additionally, in the ICG + MB group, ICG could identify more LNs than MB (3.1 vs 2.6, P = 0.004, t = 2.884).

CONCLUSION

ICG has high detection effectiveness for SLNs, and when paired with MB, the detection efficiency can be increased even further. Furthermore, the ICG + MB tracing mode does not involve radioisotopes, which has a lot of promise for clinical use and can take the place of conventional standard detection methods.

Intraoperative fluorescence molecular imaging accelerates the coming of precision surgery in China

Purpose

China has the largest cancer population globally. Surgery is the main choice for most solid cancer patients. Intraoperative fluorescence molecular imaging (FMI) has shown its great potential in assisting surgeons in achieving precise resection. We summarized the typical applications of intraoperative FMI and several new trends to promote the development of precision surgery.

Methods

The academic database and NIH clinical trial platform were systematically evaluated. We focused on the clinical application of intraoperative FMI in China. Special emphasis was placed on a series of typical studies with new technologies or high-level evidence. The emerging strategy of combining FMI with other modalities was also discussed.

Results

The clinical applications of clinically approved indocyanine green (ICG), methylene blue (MB), or fluorescein are on the rise in different surgical departments. Intraoperative FMI has achieved precise lesion detection, sentinel lymph node mapping, and lymphangiography for many cancers. Nerve imaging is also exploring to reduce iatrogenic injuries. Through different administration routes, these fluorescent imaging agents provided encouraging results in surgical navigation. Meanwhile, designing new cancer-specific fluorescent tracers is expected to be a promising trend to further improve the surgical outcome.

Conclusions

Intraoperative FMI is in a rapid development in China. In-depth understanding of cancer-related molecular mechanisms is necessary to achieve precision surgery. Molecular-targeted fluorescent agents and multi-modal imaging techniques might play crucial roles in the era of precision surgery.

Comparative Study Between Radioisotope Uptake and Fluorescence Intensity of Indocyanine Green for Sentinel Lymph Node Biopsy in Breast Cancer

Recently, several breast surgeons have reported a new method for sentinel lymph node biopsy (SLNB) by using indocyanine green (ICG) with infrared camera. This study aimed to determine whether the lymph nodes (LNs) with ICG uptake are true SLNs and to assess the reliability of using only ICG for SLNB. Data were prospectively collected between April and September 2021. All palpable LNs were fat-trimmed and ordered from high to low signal of the gamma detector. The degree of radioisotope uptake and brightness of ICG staining of the axillary LNs detected with a fluorescent camera were compared and associated factors were analyzed. Discordance was defined as sentinel LNs (SLNs) showing a single uptake of radioisotope or fluorescence of ICG only, or when the orders of uptake and intensity degree were different between the 2 materials. A total of 79 SLNBs were performed on 78 patients with breast cancer. The breast cancer was classified as cTis-2N0-1. The discordance rate was 14/79 (17.7%) overall and 45/270 (16.7%) of the total retrieved axillary LNs. The first SLNs showed the lowest discordance rate of 6.3%, whereas the second and third SLNs showed higher discordance rates of 27.6% and 60.0%, respectively. There were no associated clinicopathologic factors that affected the discordance between uptake of radioisotope and fluorescence intensity of ICG. The use of ICG alone for SLNB may be insufficient because of the high discordance rates between radioisotopes and ICG uptake. However, the first SLN could be cautiously regarded as a true SLN.

Indocyanine Green Fluorescence-Guided Sentinel Node Biopsy in Breast Cancer Within a North African Population: A Retrospective Study

Objective

Radio isotopes and blue dyes alone or in combination are the most commonly used tracer agents in sentinel node (SN) biopsy for early breast cancer. Recent studies have found fluorescence method using indocyanine green (ICG) as a promising technology with fewer disadvantages.

Materials and Methods

Retrospective analysis of our database that included patients with clinically node-negative breast cancer scheduled for breast surgery and SN biopsy between 2016 and January 2021. Patients who underwent detection using fluorescence-ICG were included in this study.

Results

A total of 47 patients were included. Median age was 50 (range: 24-78) years. Mean tumor size was 3.4 ± 1.5 cm. All patients received ICG injection and 11 received a combination of ICG and blue dye. Forty-five successful SN identifications with ICG were performed and 99 nodes retrieved. Eleven procedures were undertaken after initial systemic therapy. Twenty-four patients had at least one positive SN for malignancy. Mean follow up was 29.2 months and no axillary recurrence was noted during the study period.

Conclusion

ICG appears to be a feasible and accurate method for SN biopsy with high identification rate. This is the first study of ICG in sentinel node biopsy in a North African population.

Fluorescence Guided Surgery

Fluorescence guided surgery (FGS) is an imaging technique that allows the surgeon to visualise different structures and types of tissue during a surgical procedure that may not be as visible under white light conditions. Due to the many potential advantages of fluorescence guided surgery compared to more traditional clinical imaging techniques such as its higher contrast and sensitivity, less subjective use, and ease of instrument operation, the research interest in fluorescence guided surgery continues to grow over various key aspects such as fluorescent probe development and surgical system development as well as its potential clinical applications. This review looks to summarise some of the emerging opportunities and developments that have already been made in fluorescence guided surgery in recent years while highlighting its advantages as well as limitations that need to be overcome in order to utilise the full potential of fluorescence within the surgical environment.

Molecular Imaging, How Close to Clinical Precision Medicine in Lung, Brain, Prostate and Breast Cancers

Precision medicine is playing a pivotal role in strategies of cancer therapy. Unlike conventional one-size-fits-all chemotherapy or radiotherapy modalities, precision medicine could customize an individual treatment plan for cancer patients to acquire superior efficacy, while minimizing side effects. Precision medicine in cancer therapy relies on precise and timely tumor biological information. Traditional tissue biopsies, however, are often inadequate in meeting this requirement due to cancer heterogeneity, poor tolerance, and invasiveness. Molecular imaging could detect tumor biology characterization in a noninvasive and visual manner, and provide information about therapeutic targets, treatment response, and pharmacodynamic evaluation. This summates to significant value in guiding cancer precision medicine in aspects of patient screening, treatment monitoring, and estimating prognoses. Although growing clinical evidences support the further application of molecular imaging in precision medicine of cancer, some challenges remain. In this review, we briefly summarize and discuss representative clinical trials of molecular imaging in improving precision medicine of cancer patients, aiming to provide useful references for facilitating further clinical translation of molecular imaging to precision medicine of cancers.

Comparison of two different surgical strategies for breast cancer patients treated with mastectomy plus sentinel lymph node biopsy

Two separated incisions are generally adopted in breast cancer patients treated by mastectomy plus sentinel lymph node biopsy (SLNB). However, one-incision procedure is also applied in clinical practice. The outcomes of the two different surgical strategies remain unknown. This issue needs to be investigated. The medical records of breast cancer patients who underwent a mastectomy combined with an SLNB were reviewed retrospectively. Group A comprised patients who received a single incision for both the mastectomy and SLNB. Group B comprised patients who received a second incision for the SLNB. Demographics and outcomes were compared between the two groups. There were 280 female patients divided into Groups A (n = 130) and B (n = 150) included in this study. Preoperatively, the two groups were similar in demographics for age, tumor size, tumor location, body mass index, pathologic type, and cancer stage (P > 0.05). Group A showed shorter surgical times (129.5 ± 29.0 vs. 136.7 ± 21.9 min), less postoperative upper limb numbness (12.3% vs. 25.3%), and more harvested sentinel lymph nodes (3.2 ± 1.1 vs. 2.7 ± 1.0) than Group B (P < 0.05). There were no significant differences for intraoperative blood loss, total postoperative drainage amount, hospital stay, upper limb motility, upper limb pain, upper limb edema, number of metastatic sentinel lymph nodes, follow-up time, or recurrent cases (P > 0.05). The one-incision approach for a breast cancer mastectomy plus SLNB has several advantages over the two-incision approach, including a shorter surgical time, decreased upper limb numbness, and the harvesting of more sentinel lymph nodes. Further prospective randomized controlled clinical trials should be designed to verify the current findings.