Low-cost Fluorescein as an Alternative to Radio-colloid for Sentinel Lymph Node Biopsy-a Prospective Validation Study in Early Breast Cancer

Sentinel lymph node biopsy in early breast carcinoma using fluorescein sodium and methylene blue dye: A validation study

The availability of radioisotopes for sentinel lymph node biopsy (SLNB) in breast carcinoma is limited in low- and middle-income countries and thus the need for other reliable tracers exists. We aimed to validate the effectiveness of fluorescein sodium (FS) together with methylene blue dye (MBD) for patients with node-negative early breast carcinoma in a prospective cross-sectional study. Patients underwent SLNB using FS and MBD followed by axillary dissection to validate results. Sentinel lymph node (SLN) identification rate and false negative rate were assessed for all three tracers/combinations (MBD, FS, and MBD + FS). We concluded that SLNB using a combination of FS and MBD has an acceptable rate of SLN identification but the addition of FS provided no additional benefit.

Sentinel Lymph Node Detection in Cutaneous Melanoma Using Indocyanine Green-Based Near-Infrared Fluorescence Imaging: A Systematic Review and Meta-Analysis

The standard of care approach to identify sentinel lymph nodes (SLNs) in clinically non-metastatic cutaneous melanoma patients is technetium (Tc)-based lymphoscintigraphy. This technique is associated with radiation exposure, a long intervention time, high costs, and limited availability. Indocyanine green (ICG)-based near-infrared fluorescence imaging offers a potential alternative if proven to be of comparable diagnostic accuracy. While several clinical cohorts have compared these modalities, no systematic review exists that provides a quantitative analysis of their results. Hence, a systematic literature review was conducted in December 2023 considering clinical studies comparing the diagnostic accuracy of ICG and Tc for sentinel lymph node biopsy in cutaneous melanoma patients. Three hundred nineteen studies were identified and further screened in accordance with the PRISMA 2020 guidelines, resulting in seven studies being included in the final meta-analysis. Tc identified a significantly higher number of SLNs and metastatic SLNs in prospective studies only. However, in the overall meta-analysis of all included comparative studies, no significant differences were found regarding the identification of metastatic patients or the false negative rate (FNR). ICG may be a non-inferior alternative to Tc for intraoperative guidance in sentinel lymph node biopsy in cutaneous melanoma patients. Future randomized controlled trials are needed, especially regarding the preoperative, transcutaneous identification of the affected lymph node basin.

A systematic review and meta-analysis of diagnostic performance of fluorescein-guided sentinel lymph node biopsy in early breast cancer

BACKGROUND

Evaluation of axillary lymph nodes status in cN0 axilla is performed by sentinel lymph node biopsy (SLNB) utilizing a combination of radioactive isotope and blue dye or alternative to isotope like Indocyanine green (ICG). Both are very resource-intensive; which has prompted development of low-cost technique of Fluorescein Sodium (FS)-guided SLNB. This systematic review and meta-analysis evaluate the diagnostic performance of FS-guided SLNB in early breast cancer.

OBJECTIVES

The objective was to evaluate the diagnostic performance of FS for sentinel lymph node biopsy.

METHODS

Eligibility criteria: Studies where SLNB was performed using FS.

INFORMATION SOURCES

PubMed, EMBASE, Cochrane library and online clinical trial registers. Risk of bias: Articles were assessed for risk of bias using the QUADAS-2 tool.

SYNTHESIS OF RESULTS

The main summary measures were pooled Sentinel Lymph Node Identification Rate (SLN-IR) and pooled False Negative Rate (FNR) using random-effects model.

RESULTS

A total of 45 articles were retrieved by the initial systematic search. 7 out of the 45 studies comprising a total of 332 patients were included in the meta-analysis. The pooled SLN-IR was 93.2% (95% confidence interval [CI], 0.87-0.97; 87% to 97%). Five validation studies were included for pooling the false negative rate and included a total of 211 patients. The pooled FNR was 5.6% (95% confidence interval [CI], 2.9-9.07).

CONCLUSION

Fluorescein-guided SLNB is a viable option for detection of lymph node metastases in clinically node negative patients with early breast cancer. It achieves a high pooled Sentinel Lymph Node Identification Rate (SLN-IR) of 93% with a false negative rate of 5.6% for the detection of axillary lymph node metastasis.

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.

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

OBJECTIVE

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

INTRODUCTION

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Fluorescence-guided surgery: comprehensive review

BACKGROUND

Despite significant improvements in preoperative workup and surgical planning, surgeons often rely on their eyes and hands during surgery. Although this can be sufficient in some patients, intraoperative guidance is highly desirable. Near-infrared fluorescence has been advocated as a potential technique to guide surgeons during surgery.

METHODS

A literature search was conducted to identify relevant articles for fluorescence-guided surgery. The literature search was performed using Medical Subject Headings on PubMed for articles in English until November 2022 and a narrative review undertaken.

RESULTS

The use of invisible light, enabling real-time imaging, superior penetration depth, and the possibility to use targeted imaging agents, makes this optical imaging technique increasingly popular. Four main indications are described in this review: tissue perfusion, lymph node assessment, anatomy of vital structures, and tumour tissue imaging. Furthermore, this review provides an overview of future opportunities in the field of fluorescence-guided surgery.

CONCLUSION

Fluorescence-guided surgery has proven to be a widely innovative technique applicable in many fields of surgery. The potential indications for its use are diverse and can be combined. The big challenge for the future will be in bringing experimental fluorophores and conjugates through trials and into clinical practice, as well as validation of computer visualization with large data sets. This will require collaborative surgical groups focusing on utility, efficacy, and outcomes for these techniques.

Point-of-care devices based on fluorescence imaging and spectroscopy for tumor margin detection during breast cancer surgery: Towards breast conservation treatment

OBJECTIVE

Fluorescence-based methods are highly specific and sensitive and have potential in breast cancer detection. Simultaneous fluorescence imaging and spectroscopy during intraoperative procedures of breast cancer have great advantages in detection of tumor margin as well as in classification of tumor to healthy tissues. Intra-operative real-time confirmation of breast cancer tumor margin is the aim of surgeons, and therefore, there is an urgent need for such techniques and devices which fulfill the surgeon's priorities.

METHODS

In this article, we propose the development of fluorescence-based smartphone imaging and spectroscopic point-of-care multi-modal devices for detection of invasive ductal carcinoma in tumor margin during removal of tumor. These multimodal devices are portable, cost-effective, noninvasive, and user-friendly. Molecular level sensitivity of fluorescence process shows different behavior in normal, cancerous and marginal tissues. We observed significant spectral changes, such as, red-shift, full-width half maximum (FWHM), and increased intensity as we go towards tumor center from normal tissue. High contrast in fluorescence images and spectra are also recorded for cancer tissues compared to healthy tissues. Preliminary results for the initial trial of the devices are reported in this article.

RESULTS

A total 44 spectra from 11 patients of invasive ductal carcinoma (11 spectra for invasive ductal carcinoma and rest are normal and negative margins) are used. Principle component analysis is used for the classification of invasive ductal carcinoma with an accuracy of 93%, specificity of 75% and sensitivity of 92.8%. We obtained an average 6.17 ± 1.66 nm red shift for IDC with respect to normal tissue. The red shift and maximum fluorescence intensity indicates p < 0.01. These results described here are supported by histopathological examination of the same sample.

CONCLUSION

In the present manuscript, simultaneous fluorescence-based imaging and spectroscopy is accomplished for the classification of IDC tissues and breast cancer margin detection.

A Systematic Review and Meta-analysis of Touch Imprint Cytology and Frozen Section Biopsy and Their Comparison for Evaluation of Sentinel Lymph Node in Breast Cancer

INTRODUCTION

Evaluation of axillary lymph nodes after sentinel lymph node biopsy (SLNB) in breast cancer is mostly done by intra-operative frozen section biopsy (FSB) and/ or touch imprint cytology (TIC). In this systematic review and meta-analysis, we have compared the accuracy of the two modalities.

METHODS

PubMed, EMBASE, and Cochrane electronic databases were searched for articles comparing TIC with FSB. Articles were assessed for methodological and reporting quality. The main summary measures were pooled sensitivity, pooled specificity, and diagnostic accuracy using bivariate generalized linear mixed models using random effects.

RESULTS

Fourteen studies were included. The pooled sensitivity, specificity, and diagnostic accuracy for FSB were 78%, 100%, and 98.57%. For TIC, the pooled sensitivity, specificity, and diagnostic accuracy were 74%, 98%, and 98.37%. For both methods, visual inspection of summary ROC curves and of forest plots did not show significant heterogeneity.

CONCLUSION

TIC showed comparable sensitivity, specificity, and accuracy to FSB and hence can be used as its substitute as a rapid and economical test for the detection of axillary lymph node metastasis during SLNB especially in low-resource settings.

Clinical significance of discordances in sentinel lymph node reactivity between radioisotope and indocyanine green fluorescence in patients with cN0 breast cancer

BACKGROUND

/Objective: To evaluate the usefulness of combining radioisotopes (RI) and indocyanine green (ICG) and investigate discordances in sentinel lymph node (SN) reactivity using each tracer in cN0 breast cancer patients.

METHODS

In total, 338 cN0 primary breast cancer patients who underwent SN biopsy with RI and ICG and axillary lymph node (ALN) dissection were included. SN positivity with RI, ICG, and a combination of RI and ICG was denoted as SN(RI), SN(ICG), and SN(RI+ICG), respectively. We retrospectively estimated metastatic SN detection rates, each method's discordance rate, and the correlation of discordances in SN reactivity with postoperative N staging.

RESULTS

The combination of RI and ICG had higher metastatic SN detection rates (99.7%) than RI or ICG alone (91.7% and 96.4%, respectively; p < 0.01). The discordance rate between SN(RI) and SN(ICG) in detecting metastatic SNs was 11.3% (38/337 cases). The absence of SN(RI), cT stage (cT2-3), higher histological grade (G3), and histological type (special type) were identified as risk factors of pN2-3 disease (odds ratios: 8.64, 2.56, 1.92, and 3.28, respectively; p < 0.01).

CONCLUSION

Discordances in SN reactivity between RI and ICG helps in identifying SN metastasis. Although the absence of SN(RI) is rare, it is a significant sign of advanced ALN metastases. The findings of our study indicate that ALN dissection should be considered for accurate nodal staging in such cases.

Evaluation of New Tracers in the Identification of Sentinel Lymph Node in Patients with Early Breast Cancer

Purpose

Sentinel node mapping is the standard of care for evaluation of axilla for women with early node negative breast cancer. Validation of a new tracer for sentinel node biopsy requires full axillary lymph node dissection to establish its performance indicators. This exposes about 70% of women to unnecessary axillary dissection with its attendant morbidity.

Aims and Objective

To investigate the predictive value of identification of sentinel lymph nodes by a tracer for knowing its sensitivity and false-negative rates (FNR).

Methods

A linear regression on data from a network meta-analysis was carried out, and the correlation between identification and sensitivity and its predictive value were ascertained.

Results

A strong linear relationship was observed between identification and sensitivity of sentinel node biopsy (correlation coefficient r = 0.97). The sensitivity and false negativity can be predicted by the identification rate. An identification rate of 93% corresponds to sensitivity = 90.51% and a FNR = 9.49%. The current literature on newer tracers has been succinctly reviewed.

Conclusion

The linear regression demonstrated a very high predictive value of identification rate for ascertaining the sensitivity and FNRs of sentinel node biopsy. A new tracer for sentinel node biopsy can be introduced in clinical practice, if it achieves an identification rate of 93% or more.

The current status and future prospects for molecular imaging-guided precision surgery

Molecular imaging technologies are increasingly used to diagnose, monitor, and guide treatment of i.e., cancer. In this review, the current status and future prospects of the use of molecular imaging as an instrument to help realize precision surgery is addressed with focus on the main components that form the conceptual basis of intraoperative molecular imaging. Paramount for successful interventions is the relevance and accessibility of surgical targets. In addition, selection of the correct combination of imaging agents and modalities is critical to visualize both microscopic and bulk disease sites with high affinity and specificity. In this context developments within engineering/imaging physics continue to drive the growth of image-guided surgery. Particularly important herein is enhancement of sensitivity through improved contrast and spatial resolution, features that are critical if sites of cancer involvement are not to be overlooked during surgery. By facilitating the connection between surgical planning and surgical execution, digital surgery technologies such as computer-aided visualization nicely complement these technologies. The complexity of image guidance, combined with the plurality of technologies that are becoming available, also drives the need for evaluation mechanisms that can objectively score the impact that technologies exert on the performance of healthcare professionals and outcome improvement for patients.

Sentinel Node Mapping in Early Breast Cancer: A Randomized Comparison of Fluorescein Guided All India Institute of Medical Sciences, Anurag's Technique with Technetium-99 m Sulfur Colloid Plus Methylene Blue

Purpose

Evaluation of fluorescein along with blue dye as an affordable tracer for sentinel node biopsy in comparison with technetium + methylene blue. A randomized trial was conducted with the following objectives: (1) to demonstrate that the identification of sentinel lymph node by fluorescein + methylene blue is not inferior to the identification by Tc-99 m sulfur colloid + methylene blue and (2) to evaluate the cost-effectiveness of sentinel node biopsy by above two tracers.

Subjects and Methods

One-thirty patients above age 18 years presenting with early breast cancer T1, T2, N0 breast carcinoma were randomized to undergo sentinel node biopsy by either fluorescein + methylene blue or Tc-99 m sulfur colloid + methylene blue.

Results

The sentinel lymph nodes were identified in 89% in Fluorescein + methylene blue group and 90.9% with Tc-99 m sulfur colloid + methylene blue group. The trial demonstrated noninferiority of fluorescein + methylene blue as compared to isotope + methylene blue with effect size = 1; 95% confidence interval- 9.54 to + 11.54. The fluorescein + methylene blue was more cost-effective than isotope guided sentinel node biopsy.

Conclusion

Fluorescein-guided sentinel node biopsy is noninferior and more cost-effective than isotope-guided sentinel node biopsy.

Validation sentinel lymph node biopsy study in cN0 axilla using low-cost dual dye technique: potential solution for resource poor settings

BACKGROUND

Sentinel lymph node biopsy (SLNB) using radio-pharmaceutical and a blue dye is gold standard for axillary staging in clinically node-negative breast cancer. High costs and limited availability of radio-pharmaceutical and/or gamma probe are major deterrents in performing SLNB in developing countries. In this study, we evaluated feasibility of SLN identification (SLN-IR) of fluorescein-guided (FG) SLNB in combination with methylene blue dye (MBD).

METHODS

This was a prospective cross-sectional non-randomized validation study in patients with clinically node-negative axilla. Patients underwent validation SLNB using fluorescein (and blue LED light) and MBD. Axillary dissection was performed irrespective of SLNB histology. SLIN-IR and False Negative Rate (FNR) were assessed for both groups.

RESULTS

The SLNs were identified in 29 (96.6%) pre-chemotherapy patients and 23 (82%) post Neoadjuvant Chemotherapy (NACT) patients. The median number of sentinel lymph nodes identified was 3 (range of 1-5) in pre-chemotherapy patients and 1 (range of 1-3) in post NACT patients. The SLN-IR using MBD was 90%, FD was 86.7% and combined MBD FD was 96.7% in pre-chemotherapy patients. The SLN-IR using MBD was 82%, FD was 71% and combined MBD FD was 82% in in post NACT patients. The false negative rate (FNR) in pre-chemotherapy group was 8.0% (MBD), 8.3% (FD) and 7.4% (MBD + FD). The FNR in post NACT group was 8.7% (MBD), 10% (FD) and 8.7% (MBD + FD).

CONCLUSION

This prospective validation study showed adequate SLN-IR and FNR using low-cost dual dyes in early breast cancer patients and can be used in low resource settings. However, SLNB in post NACT axilla though viable along with a satisfactory FNR, is associated with low identification rate and needs further evaluation.

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.