Factors that affect the false negative rate of sentinel lymph node mapping with methylene blue dye alone in breast cancer

Predictive nomogram using multimodal ultrasonographic features for axillary lymph node metastasis in early‑stage invasive breast cancer

Axillary lymph node (ALN) status is a key prognostic factor in patients with early-stage invasive breast cancer (IBC). The present study aimed to develop and validate a nomogram based on multimodal ultrasonographic (MMUS) features for early prediction of axillary lymph node metastasis (ALNM). A total of 342 patients with early-stage IBC (240 in the training cohort and 102 in the validation cohort) who underwent preoperative conventional ultrasound (US), strain elastography, shear wave elastography and contrast-enhanced US examination were included between August 2021 and March 2022. Pathological ALN status was used as the reference standard. The clinicopathological factors and MMUS features were analyzed with uni- and multivariate logistic regression to construct a clinicopathological and conventional US model and a MMUS-based nomogram. The MMUS nomogram was validated with respect to discrimination, calibration, reclassification and clinical usefulness. US features of tumor size, echogenicity, stiff rim sign, perfusion defect, radial vessel and US Breast Imaging Reporting and Data System category 5 were independent risk predictors for ALNM. MMUS nomogram based on these factors demonstrated an improved calibration and favorable performance [area under the receiver operator characteristic curve (AUC), 0.927 and 0.922 in the training and validation cohorts, respectively] compared with the clinicopathological model (AUC, 0.681 and 0.670, respectively), US-depicted ALN status (AUC, 0.710 and 0.716, respectively) and the conventional US model (AUC, 0.867 and 0.894, respectively). MMUS nomogram improved the reclassification ability of the conventional US model for ALNM prediction (net reclassification improvement, 0.296 and 0.288 in the training and validation cohorts, respectively; both P<0.001). Taken together, the findings of the present study suggested that the MMUS nomogram may be a promising, non-invasive and reliable approach for predicting ALNM.

Indocyanine Green and Methylene Blue Dye Guided Sentinel Lymph Node Biopsy in Early Breast Cancer: A Single-Center Retrospective Survival Study in 1574 Patients

BACKGROUND

Currently, the standard tracing method is to use blue dyes and radioisotope as the tracer for sentinel lymph node biopsy (SLNB). However, there are variations in the choice of tracer in different countries and regions. Some new tracers are also gradually applied in clinical practice, but there is still a lack of long-term follow-up data to confirm their clinical application value.

PATIENTS AND METHODS

Clinicopathological and postoperative treatment follow-up data were collected from patients with early-stage cTis-2N0M0 breast cancer who underwent SLNB using a dual-tracer method of ICG combined with MB. Statistical indicators including the identification rate, the number of sentinel lymph nodes (SLNs), regional lymph node recurrence, disease-free survival (DFS) and overall survival (OS) were analyzed.

RESULTS

Among the 1574 patients, SLNs were successfully detected during surgery in 1569 patients, with a detection rate of 99.7%; the median number of SLNs removed was 3. A total of 1531 patients were included in the survival analysis, with a median follow-up of 4.7 (0.5-7.9) years. In total, patients with positive SLNs had a 5-year DFS and OS of 90.6% and 94.7%, respectively. The 5-year DFS and OS of patients with negative SLNs were 95.6% and 97.3%, respectively. The postoperative regional lymph node recurrence rate was 0.7% in patients with negative SLNs.

CONCLUSION

Indocyanine green combined with methylene blue dual-tracer method is safe and effective in sentinel lymph node biopsy in patients with early breast cancer.

Applying Explainable Machine Learning Models for Detection of Breast Cancer Lymph Node Metastasis in Patients Eligible for Neoadjuvant Treatment

BACKGROUND

Due to recent changes in breast cancer treatment strategy, significantly more patients are treated with neoadjuvant systemic therapy (NST). Radiological methods do not precisely determine axillary lymph node status, with up to 30% of patients being misdiagnosed. Hence, supplementary methods for lymph node status assessment are needed. This study aimed to apply and evaluate machine learning models on clinicopathological data, with a focus on patients meeting NST criteria, for lymph node metastasis prediction.

METHODS

From the total breast cancer patient data (n = 8381), 719 patients were identified as eligible for NST. Machine learning models were applied for the NST-criteria group and the total study population. Model explainability was obtained by calculating Shapley values.

RESULTS

In the NST-criteria group, random forest achieved the highest performance (AUC: 0.793 [0.713, 0.865]), while in the total study population, XGBoost performed the best (AUC: 0.762 [0.726, 0.795]). Shapley values identified tumor size, Ki-67, and patient age as the most important predictors.

CONCLUSION

Tree-based models achieve a good performance in assessing lymph node status. Such models can lead to more accurate disease stage prediction and consecutively better treatment selection, especially for NST patients where radiological and clinical findings are often the only way of lymph node assessment.

Ultrasound contrast-enhanced patterns of sentinel lymph nodes: predictive value for nodal status and metastatic burden in early breast cancer

Background

In the post-Z0011 era, sentinel lymph node (SLN) status and metastatic burden determine whether axillary management entails conservative sentinel lymph node biopsy (SLNB) or radical axillary lymph node dissection (ALND) in breast cancer patients. However, SLN status and metastatic burden cannot be evaluated preoperatively in clinical practice. This study explored the predictive value of contrast-enhanced ultrasound (CEUS) patterns of SLN to assess the nodal status and metastatic burden in early breast cancer patients.

Methods

A retrospective study was conducted on 88 consecutive patients who were diagnosed with clinical T1-2N0 breast cancer between December 2020 and November 2021 at the Lanzhou University Second Hospital and scheduled for SLNB. Preoperative CEUS was performed to confirm the location and enhancement pattern of the SLN, and the conventional ultrasonic characteristics of the primary breast lesions and SLN were recorded. Intraoperative localized SLN and postoperative pathological results were used as the gold standard for comparison with preoperative ultrasound findings.

Results

CEUS successfully identified at least 1 SLN in 88 patients, with a total of 118 SLNs identified in the entire cohort. Univariate analysis showed that lesion size, blood flow grade, SLN longitudinal diameter, cortical thickness, and enhancement pattern were significant predictive features of SLN metastasis. Further multiple regression analysis indicated that the enhancement pattern of the SLN was an independent risk factor for SLN metastasis, with a sensitivity and a specificity of 84.2% (32/38) and 80.0% (40/50), respectively. Meanwhile, the SLN enhancement pattern could predict the lymph node metastasis burden (P<0.001). In patients presenting with a type I (homogeneous enhancement) or type II (heterogeneous enhancement) SLN, 91.5% (65/71) had ≤2 positive SLNs, whereas in patients with a type III (no enhancement) SLN, 70.6% (12/17) had >2 metastatic nodes.

Conclusions

The contrast-enhanced pattern of the SLN is an independent risk factor for SLN status. Patients presenting with a type I or type II SLN enhanced pattern are unlikely to have high-burden metastases detected at their final surgical treatment and omission of ALND may be appropriate.

Study on intraoperative localization of sentinel lymph nodes using freehand SPECT in breast cancer patients

Introduction

The diagnostic and therapeutic approach to axillary lymph nodes is considered indispensable in the treatment of breast cancer patients.

Aim

To investigate the effectiveness of 3D freehand SPECT (fhSPECT) in sentinel lymph node (SLN) mapping in breast cancer, compared with the use of a conventional gamma probe.

Material and methods

We retrospectively compared the fhSPECT lymph node mapping modality, with gamma probe detection in early-stage, clinically node-negative breast cancer patients, with biopsy-confirmed malignancy. The two techniques were compared based on the average number of LNs excised per axilla. The duration of SLN mapping was also compared between the two groups. The performance of the two methods on obese and post-systemic therapy patients was evaluated. FhSPECT was used in 150 cases, while the gamma probe was employed in 50 cases.

Results

FhSPECT detected at least 3 nodes in 83.3% of the patients vs. 72.0% with the γ-probe (p = 0.107). The mean number of SLNs excised per axilla was 3.66 using the γ-probe and 4.18 with fhSPECT (p = 0.03). The average surgical time was 39 ±7 min with the γ-probe and 37.54 ±17 min with fhSPECT (p = 0.228). Sentinel lymph node biopsy (SLNB) mean surgical time evolved from 40.2 ±20.77 min to 32.35 ±10.46 min (p = 0.033). In obese patients, a reduction in surgical times was noted from 45.5 ±3.09 min to 44.04 ±20.9 (p = 0.27), in addition to a significant increase in average LN detection in the fhSPECT group (4.26 ±1.44) compared to the γ-probe group (3.2 ±1.65) (p = 0.043).

Conclusions

The use of the fhSPECT modality is effective and safe, and, when compared to the γ-probe, has significant advantages in SLN mapping.

Associations between the Levels of Estradiol-, Progesterone-, and Testosterone-Sensitive MiRNAs and Main Clinicopathologic Features of Breast Cancer

Despite the existing advances in the diagnosis and treatment of breast cancer (BC), the search for markers associated with the clinicopathological features of BC is still in demand. MiRNAs (miRs) have potential as markers, since a change in the miRNA expression profile accompanies the initiation and progression of malignant diseases. The receptors for estrogen, androgen, and progesterone (ER, AR, and PR) play an important role in breast carcinogenesis. Therefore, to search for miRNAs that may function as markers in BC, using bioinformatic analysis and the literature data, we selected 13 miRNAs whose promoter regions contain binding sites for ER or AR, or putative binding sites for ER, AR, and PR. We quantified their expression in MCF-7 cells treated with estradiol, progesterone, or testosterone. The levels of miRNAs sensitive to one or more of these hormones were quantified in BC samples (n = 196). We discovered that high expression levels of miR-190b in breast tumor tissue indicate a positive ER status, and miR-423 and miR-200b levels differ between patients with and without HER2 amplification. The miR-193b, -423, -190a, -324, and -200b levels were associated with tumor size or lymph node status in BC patients, but the presence of these associations depended on the status and expression level of ER, PR, HER2, and Ki-67. We also found that miR-21 expression depends on HER2 expression in ER- and/or PR-positive BC. The levels of miRNA were significantly different between HER2 0 and HER2 1+ tumors (p = 0.027), and between HER2 0 and HER2 2+, 3+ tumors (p = 0.005).

Quantitative and Semi-quantitative Methods for Assessing the Degree of Methylene Blue Staining in Sentinel Lymph Nodes in Dogs

Background: To develop a digital algorithm for quantitative assessment of surface methylene blue staining in whole lymph nodes and validate a semi-quantitative visual scoring method for patient-side use.

Methods: Lymph nodes from canine patients with spontaneous tumors undergoing sentinel lymph node mapping were prospectively assessed ex vivo and photographed. Using an open-source computer-based imaging software, an algorithm was developed for quantification of staining based on a signal-to-background ratio. Next, two blinded observers evaluated images and assigned a semi-quantitative visual score based on surface staining (0—no blue stain, 1−1–50% stained, and 2−51–100% stained) and those results were compared to the established quantitative standard.

Results: Forty-three lymph nodes were included. Image analysis successfully quantified blue staining and differentiated from normal lymph node tissue in all cases. Agreement between observers using the Kappa coefficient demonstrated strong agreement (k = 0.8581, p < 0.0001) between semi-quantitative visual scoring and image analysis. There was substantial interobserver and intraobserver agreement for the scoring system (k = 0.7340, p < 0.0001 and k = 0.8983, p < 0.0001, respectively).

Conclusion: A digital algorithm using an open-source software was simple and straightforward to use for quantification of blue staining. The use of a semi-quantitative visual scoring system shows promise for a simple, objective, repeatable assessment of methylene blue staining at the time of surgery. This study demonstrates reliable and repeatable methods for blue staining quantification thereby providing a novel and objective reporting mechanism in scientific research involving sentinel lymph node mapping.

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.

Techniques for sentinel node biopsy in breast cancer

INTRODUCTION

Sentinel node biopsy (SNB) is the standard of care in women with breast cancer (BC) and clinically non suspicious axillary lymph nodes (LNs), due to its high negative predictive value (NPV) in the assessment of nodal status. SNB has significantly reduced complications related to the axillary lymph node dissection, such as lymphedema and upper limb dysfunction.

EVIDENCE ACQUISITION

The gold standard technique for SNB is the blue dye (BD) and technetium labelled nanocolloid (Tc-99m) double technique. However, nuclear medicine is not available in all Institutions and several new tracers and devices have been proposed, such as indocyanine green (ICG) and superparamagnetic iron oxides (SPIO). All these techniques show an accuracy and detection rate not inferior to that of the standard technique, with different specific pros and cons. The choice of how to perform a SNB primarily depends on the surgeon's confidence with the procedure, the availability of nuclear medicine and the economic resources of the Institutions. In this setting, new tracers, hybrid tracers and imaging techniques are being evaluated in order to improve the detection rate of sentinel lymph nodes (SNs) and minimize the number of unnecessary axillary surgeries through an accurate preoperative assessment of nodal status and to guide new minimally invasive diagnostic procedures of SNs. In particular, the contrast-enhanced ultrasound (CEUS) is an active field of research but cannot be recommended for clinical use at this time.

EVIDENCE SYNTHESIS

The ICG fluorescence technique was superior in terms of DR, as well as having the lowest FNR. The DR descending order was SPIO, Tc, dual modality (Tc/BD), CEUS and BD.

CONCLUSIONS

This paper is a narrative review of the most common SNB techniques in BC with a focus on recent innovations.

Comparative study of two contrast agents for intraoperative identification of sentinel lymph nodes in patients with early breast cancer

Background

The use of contrast-enhanced ultrasound (CEUS) to locate sentinel lymph nodes (SLNs) in breast cancer has been studied more and more in recent years. This prospective study aimed to compare periareolar injection of two different contrast agents, SonoVue^® (SNV) and Sonazoid^® (SNZ), followed by CEUS to identify SLNs in breast cancer patients with clinically negative nodes.

Methods

A total of 205 patients with T1-2N0M0 breast cancer were divided into the SNV group and SNZ group. All were administered a periareolar injection of SNV or SNZ and underwent US to identify contrast-enhanced SLNs. Each contrast-enhanced SLN underwent a biopsy with blue dye and examined again by CEUS in vitro.

Results

In all cases, contrast-enhanced lymphatic vessels were clearly visualized using US soon after the periareolar injection of SNZ, and the SLNs were easily identified. The SLN identification rates were 75.27% (210/279) for SNV and 93.58% (102/109) for SNZ. Although the accuracy of detecting SLN metastasis was slightly different between the two groups, there was no statistically significant difference between those groups (P=0.615). Moreover, it was possible to identify SLNs in vitro in the SNZ group, and these could be compared with the lymph nodes (LNs) located using SNZ during the preoperative stage and with blue dye during the procedure. This helped in determining the resection requirements.

Conclusions

When comparing the subdermal use of SNV and SNZ, no significant differences in the number of detected SLNs and the diagnosis of metastatic LNs were observed. Because SLNs can be detected for a longer time in living tissues with SNZ, this contrast agent may provide more intraoperative information for complete resection of all preoperative localization of SLN.

Sentinel lymph node biopsy should be considered for clinically node-negative breast cancer regardless of BRCA1/2 mutation status

Background

BRCA1/2 mutations lead to an elevated risk of breast cancer. None involved in whether BRCA1/2 mutation status will affect the first decision-making of sentinel lymph node (SLN) biopsy or not for clinically node-negative breast cancer. We retrospectively investigated whether BRCA1/2 mutation status influenced SLN involvement rate and survival outcomes after sentinel lymph node biopsy (SLNB) for Chinese clinically node-negative breast cancer patients.

Methods

Patients who underwent SLNB at initial were enrolled and divided according to BRCA1/2 mutation status. Germline DNA for BRCA1/2 testing was derived from blood samples. SLN involvement rate and clinicopathological characteristics were analyzed using the Chi-square test. Kaplan–Meier univariate and multivariate Cox regression analysis was performed to compare survival between groups.

Results

According to BRCA1/2 mutation test criteria, 156 Chinese women receiving initial SLNB with clinically node-negative breast cancer were selected—thirty-one patients identified as BRCA1/2 mutation carriers and 102 as non-carriers were enrolled. Non-carriers seemed to be with a more advanced TNM stage (P<0.01) compared to the non-carrier group. Once SLN involved, the patient will receive axillary lymph node dissection in which BRCA1/2 mutation did not increase the rate (P=0.73). Disease-free survival (DFS) (P=0.48) and recurrence-free survival (RFS) (P=0.79) are comparable between groups, even after adjustment for clinicopathological characteristics, systemic treatment, and surgical management of breast [DFS, hazard ratio (HR) =1.63, confidence interval (CI): 0.48–5.54, P=0.43; RFS, HR =0.75, CI: 0.14–3.89, P=0.73].

Conclusions

SLNB should be considered for clinically node-negative breast cancer regardless of BRCA1/2 status.

Comparison of indocyanine green fluorescence and methylene blue dye in the detection of sentinel lymph nodes in breast cancer

Background

Previous studies have shown that sentinel lymph node biopsy (SLNB) can be successfully performed using methylene blue (MB); however, this method still has some drawbacks. Indocyanine green (ICG) fluorescence imaging, as a selective method, has the potential for guiding SLNB. This study aimed to compare the clinical sensitivity and efficacy between ICG and MB in SLNB in breast cancer.

Methods

A prospective study of 70 patients with biopsy-proven invasive breast cancer was conducted. Under the guidance of ICG and MB, administered by injection, SLNs were examined and removed. The detection rates, total number of SLNs detected, mean number of SLNs detected, and number of positive SLNs were compared between ICG and MB.

Results

The SLN detection rate was 100% and 93% (65/70) for ICG and MB, respectively. More SLNs were detected in the ICG group (243) than in the MB group (169). The mean number of SLNs detected with ICG and MB was 3.5±1.73 and 2.4±1.49, respectively. Moreover, there was a statistically significant difference between the number of SLNs detected using the two methods (t=6.648, P<0.05). Additionally, SLN metastasis was detected in 18 patients using ICG and 14 patients using MB; these patients immediately underwent axillary lymph node dissection (ALND). No postoperative complications were reported.

Conclusions

ICG demonstrated a higher detection rate and better accuracy, as well as a lower false negative rate, than MB in detecting SLNs in breast cancer. ICG has potential as an alternative tool that could be clinically applied to detect SLNs in breast cancer patients.

Clinical value of postoperative sentinel lymph node biopsy

Background

This study analyzed the clinical data and general information of breast cancer patients who were admitted by the Affiliated Hospital of Nantong University and underwent lumpectomy, followed by sentinel lymph node biopsy (SLNB) to investigate the effect of tumor location on the sentinel lymph node (SLN) detection rate, obtain a clear understanding of the SLNB procedure and further promote the use of this procedure in the local area.

Methods

This study involved a total of 118 patients who were diagnosed with breast cancer and admitted by the Affiliated Hospital of Nantong University for lumpectomy and SLNB between July 2015 and June 2019. An analysis was conducted to explore the role of tumor location in the detection of SLNs.

Results

Tumor location was associated with the success rate of post-lumpectomy SLNB. In the case of tumor location in the upper outer quadrant (UOQ) of the breast near the axilla, the SLN detection rate was relatively low. In contrast, when a tumor occurred in any of the other quadrants or the UOQ next to the areola, the tumor location had no significant impact on the SLN detection rate. SLNB indicated that 102 out of the 118 patients had SLNs, with the detection rate of 86.4%. Particularly, for patients whose tumors were located in the UOQ near their axillae, the SLN detection rate was 30% (3/10). As to tumor location in other quadrants or the UOQ next to the areola, the SLN detection rate was up to 90.8% (99/109).

Conclusions

The performance of post-lumpectomy SLNB is associated with tumor location. SLNB is recommended when the tumor site lies in the upper inner/lower outer/lower inner quadrants (UIQ/LOQ/LIQ) of the breast or the UOQ next to the areola. If the SLNB result turns out to be negative, there is no need to perform axillary lymph node dissection (ALND). For tumor location in the UOQ of the breast, especially when it is near the axilla, SLNB is not a favorable option after lumpectomy. It is recommended that the patient receive a core needle biopsy (CNB) before SLNB.