The Basics of Sentinel Lymph Node Biopsy: Anatomical and Pathophysiological Considerations and Clinical Aspects

Infrared Fluorescence-guided Surgery for Tumor and Metastatic Lymph Node Detection in Head and Neck Cancer

In patients with head and neck cancer (HNC), surgical removal of cancerous tissue presents the best overall survival rate. However, failure to obtain negative margins during resection has remained a steady concern over the past 3 decades. The need for improved tumor removal and margin assessment presents an ongoing concern for the field. While near-infrared agents have long been used in imaging, investigation of these agents for use in HNC imaging has dramatically expanded in the past decade. Targeted tracers for use in primary and metastatic lymph node detection are of particular interest, with panitumumab-IRDye800 as a major candidate in current studies. This review aims to provide an overview of intraoperative near-infrared fluorescence-guided surgery techniques used in the clinical detection of malignant tissue and sentinel lymph nodes in HNC, highlighting current applications, limitations, and future directions for use of this technology within the field. Keywords: Molecular Imaging-Cancer, Fluorescence © RSNA, 2024.

Current analysis of the survival implications for minimally invasive surgery in the treatment of early-stage cervix cancer

Early-stage cervical cancer (ESCC) is managed with radical hysterectomy, a procedure that can be performed either via open surgery or minimally invasive surgery (MIS), the latter of which is accomplished via traditional laparoscopy or robotic-assisted surgery. Previously, MIS was routinely incorporated into the management of ESCC due to the approach's reduced operative morbidity and truncated hospital stay duration, but more recent clinical evidence has since impugned the efficacy of MIS because of the reportedly inferior disease-free survival and overall survival outcomes compared to open surgery. However, additional studies have documented equivalent outcomes among the various surgical modalities, suggesting further exploration of clinical factors as we endeavor to conclusively determine the standard of care for patients diagnosed with ESCC.

Factors Affecting the Efficiency of Near-Infrared Indocyanine Green (NIR/ICG) in Lymphatic Mapping for Colorectal Cancer: A Systematic Review

As laparoscopy gained global popularity in oncologic surgery, the challenge of detecting lymph nodes spurred researchers to explore innovative techniques and approach the situation from a fresh perspective. While many proposed methods have faded into obscurity, the utilization of indocyanine green (ICG) in the surgical treatment of oncologic patients has continued to advance. The immense potential of this dye is widely acknowledged, yet its full extent and limitations in lymphatic mapping for colorectal cancer remain to be precisely determined. This article aims to assess the magnitude of its potential and explore the constraints based on insights from clinical studies published by pioneering researchers. A systematic review of the existing literature, comprising articles in English, was conducted using the Scopus, PubMed, and Springer Link databases. The search employed keywords such as "colorectal cancer" AND/OR "indocyanine green," "fluorescence" AND/OR "lymphatic mapping" AND/OR "lymph nodes." Initially identifying 129 articles, the application of selection criteria narrowed down the pool to 10 articles, which served as the primary sources of data for our review. Despite the absence of a standardized protocol for the application of ICG in colorectal cancer, particularly in the context of lymphatic mapping, the detection rates have exhibited considerable variation across studies. Nevertheless, all authors unanimously regarded this technique as beneficial and promising. Additionally, it is advocated as an adjunctive tool to enhance the accuracy of cancer staging. Near-infrared (NIR)-enhanced surgery holds the promise of transforming the landscape of oncologic surgery, emerging as a valuable tool for surgeons. However, the absence of a standardized technique and the subjective nature of result assessment impose limitations on the potential of this method. Consequently, it can be inferred that the establishment of a universally accepted protocol, encompassing parameters such as dose, concentration, technique, and site of administration of ICG, along with the optimal time needed for fluorescence visualization, would enhance the outcomes. Emphasizing the accurate selection of patients is crucial to prevent the occurrence of false-negative results.

The role of sentinel lymph node biopsy in extramammary paget disease: a systematic review

Sentinel lymph node biopsy is increasingly used to detect subclinical nodal metastases in extramammary Paget disease. We performed a comprehensive systematic review of the literature to further explore the role of sentinel lymph node biopsy in extramammary Paget disease. Five databases were searched for relevant terms. Articles were included if they were in English and presented primary data on at least one patient with extramammary Paget disease who underwent sentinel lymph node biopsy in the absence of lymphadenopathy or known metastatic disease. Twenty-eight articles were included, with 366 subjects. Seventy-seven sentinel node biopsies (21.2%) were positive, including 12 in which the primary tumor had microinvasion (15.6%) and 56 with deep invasion (72.7%). Of the positive cases, 11 (14.3%) had no further treatment, 54 (70.1%) underwent nodal dissection, 4 (5.2%) were treated with systemic agents, and 1 (1.3%) had radiation. After a mean follow up of 24 months, 9 subjects with a positive lymph node biopsy experienced nodal recurrence (11.7%), 15 had distant metastases (19.5%), and 13 died of the disease (16.9%). In conclusion, invasive extramammary Paget disease is strongly associated with poor outcomes including nodal metastasis, distant metastasis, and disease specific death. Sentinel lymph node biopsy is a useful tool to screen for subclinical nodal metastases in invasive disease, and can be used to help guide clinical management.

Sentinel lymph node assessment in melanoma: current state and future directions

Assessment of sentinel lymph node status is an important step in the evaluation of patients with melanoma for both prognosis and therapeutic management. Pathologists have an important role in this evaluation. The methodologies have varied over time, from the evaluation of dimensions of metastatic burden to determination of the location of the tumour deposits within the lymph node to precise cell counting. However, no single method of sentinel lymph node tumour burden measurement can currently be used as a sole independent predictor of prognosis. The management approach to sentinel lymph node-positive patients has also evolved over time, with a more conservative approach recently recognised for selected cases. This review gives an overview of past and current status in the field with a glimpse into future directions based on prior experiences and clinical trials.

Role of Nuclear Sentinel Lymph Node Mapping Compared to New Alternative Imaging Methods

With the emergence of sentinel node technology, many patients can be staged histopathologically using lymphatic mapping and selective lymphadenectomy. Structural imaging by using US, CT and MR permits precise measurement of lymph node volume, which is strongly associated with neoplastic involvement. Sentinel lymph node detection has been an ideal field of application for nuclear medicine because anatomical data fails to represent the close connections between the lymphatic system and regional lymph nodes, or, more specifically, to identify the first draining lymph node. Hybrid imaging has demonstrated higher accuracy than standard imaging in SLN visualization on images, but it did not change in terms of surgical detection. New alternatives without ionizing radiations are emerging now from "non-radiological" fields, such as ophthalmology and dermatology, where fluorescence or opto-acoustic imaging, for example, are widely used. In this paper, we will analyze the advantages and limits of the main innovative methods in sentinel lymph node detection, including innovations in lymphoscintigraphy techniques that persist as the gold standard to date.

More than Just Skin-Deep: A Review of Imaging's Role in Guiding CAR T-Cell Therapy for Advanced Melanoma

Advanced melanoma is one of the deadliest cancers, owing to its invasiveness and its propensity to develop resistance to therapy. Surgery remains the first-line treatment for early-stage tumors but is often not an option for advanced-stage melanoma. Chemotherapy carries a poor prognosis, and despite advances in targeted therapy, the cancer can develop resistance. CAR T-cell therapy has demonstrated great success against hematological cancers, and clinical trials are deploying it against advanced melanoma. Though melanoma remains a challenging disease to treat, radiology will play an increasing role in monitoring both the CAR T-cells and response to therapy. We review the current imaging techniques for advanced melanoma, as well as novel PET tracers and radiomics, in order to guide CAR T-cell therapy and manage potential adverse events.

The Characteristics of Sentinel Lymph Node Biopsy in Cutaneous Melanoma and the Particularities for Elderly Patients-Experience of a Single Clinic

BACKGROUND

Melanoma is a malignant tumor that determines approximately 80% of deaths as skin cancer-related. The sentinel lymph node (SLN) represents the first filter of tumor cells toward systemic dissemination. The primary objective was to outline the surgical specifics of the sentinel lymph node biopsy (SLNB) technique, correlate the location of the lymph node with the radiotracer load, and identify the characteristics of older patients.

METHODS

In this prospective study, 122 cases of malignant melanoma needing SLNB technique were included, between June 2019 and November 2022, resulting in 162 lymph nodes removed.

RESULTS

Patients' mean age was 54.3 ± 14.4 years old, the prevalence of 70 years and older being 20.5%. The rate of positive SLN was 24.6%, with a single drainage in 68.9% of cases. The frequency of seroma was 14.8%, while reintervention 1.6%. The inguinal nodes had the highest preoperative radiotracer load (p = 0.015). Patients 70 years old or older had significantly more advanced-stage melanoma (68.0% vs. 45.4%, p = 0.044, OR = 2.56) and a higher rate of positive SLN (40.0% vs. 20.6%, p = 0.045,OR = 2.57). Melanoma of the head and neck was more common among older individuals (32.0% vs. 9.3%, p = 0.007,OR = 4.60).

CONCLUSIONS

The SLNB has a low rate of surgical complications and the positivity of SLN is not related to radiotracer load. Elderly patients are at risk for head and neck melanoma, have more advanced stages, a higher SLN positivity, and a greater rate of surgical complications.

The location of metastatic lymph nodes and the evaluation of lymphadenectomy by near-infrared photoacoustic imaging with iridium complex nanoparticles

Histopathology evaluation and lymphadenectomy of node-positive patients is the usual procedure in clinical therapy. However, it requires days for the histopathology result analysis, which impedes intraoperative decision-making and immediate treatment. Noninvasive real-time imaging of metastatic lymph nodes can overcome these defects and help medical workers evaluate lymph nodes and make the operation decision more efficiently. Herein we developed iridium(III)-cyanine complex/bovine serum albumin (BSA)-based nanoparticles which are conjugated with folic acid (FA) (IrCy-FA NPs). The synthesized IrCy-FA NPs exhibit good biocompatibility, strong near-infrared absorption, and impressive lymph node accumulation and can serve as a photoacoustic (PA) imaging probe for lymph node imaging. Besides, the lymph nodes enriched with IrCy-FA NPs showing green color are easily visible to the naked eye, suggesting their potential as an intraoperative indicator. The real-time PA imaging with excellent contrast and high spatial resolution can promote efficient and reliable quantitative analysis of lymph nodes in vivo. By employing IrCy-FA NPs as the PA agent for lymph node imaging, we achieve effective pre-operative and post-operative evaluations of metastatic lymph nodes in lymphadenectomy. This study may provide helpful information for PA imaging guided colocalization and evaluation of lymph nodes and facilitate this method towards clinical trials.

Anatomical site and size of sentinel lymph node metastasis predicted additional axillary tumour burden and breast cancer survival

AIMS

Sentinel lymph node (SLN) biopsy is the current standard assessment for tumour burden in axillary lymph node (ALN). However, not all SLN+ patients have ALN metastasis. The prognostic implication of SLN features is not clear. We aimed to evaluate predictive factors for ALN metastasis and the clinical value of SLN features.

METHODS AND RESULTS

A total of 228 SLN+ and 228 SLN- (with matched year and grade) cases were included. Clinicopathological features in SLN, ALN and primary tumours, treatment data and survival data were analysed according to ALN status and outcome. Except for larger tumour size and the presence of LVI (both P < 0.001), no significant differences were found in SLN- and SLN+ cases. Only 31.8% of SLN+ cases with ALN dissection had ALN metastasis. The presence of macrometastases (MaM), extranodal extension (ENE), deeper level of tumour invasion in SLN and more SLN+ nodes were associated with ALN metastasis (P ≤ 0.025). Moreover, isolated tumour cells (ITC) and level of tumour invasion in SLN were independent adverse prognostic features for disease-free survival and breast cancer-specific survival, respectively. Interestingly, cases with ITC located in the subcapsular region have better survival than those in cortex (OS: χ²  = 4.046, P = 0.044).

CONCLUSIONS

Our study identified features in SLN, i.e. the level of tumour invasion at SLN and tumour size in SLN as useful predictors for both ALN metastasis and breast cancer outcome. The presence of ITC, particularly those with a deeper invasion in SLN, portended a worse prognosis. Proper attention should be taken for their management.

Phosphorylcholine-conjugated gold-molecular clusters improve signal for Lymph Node NIR-II fluorescence imaging in preclinical cancer models

Sentinel lymph node imaging and biopsy is important to clinical assessment of cancer metastasis, and novel non-radioactive lymphographic tracers have been actively pursued over the years. Here, we develop gold molecular clusters (Au₂₅) functionalized by phosphorylcholine (PC) ligands for NIR-II (1000–3000 nm) fluorescence imaging of draining lymph nodes in 4T1 murine breast cancer and CT26 colon cancer tumor mouse models. The Au-phosphorylcholine (Au-PC) probes exhibit ‘super-stealth’ behavior with little interactions with serum proteins, cells and tissues in vivo, which differs from the indocyanine green (ICG) dye. Subcutaneous injection of Au-PC allows lymph node mapping by NIR-II fluorescence imaging at an optimal time of ~ 0.5 − 1 hour postinjection followed by rapid renal clearance. Preclinical NIR-II fluorescence LN imaging with Au-PC affords high signal to background ratios and high safety and biocompatibility, promising for future clinical translation.

Fluorescent tracers facilitate the identification and subsequent collection of tumour draining lymph node biopsies, enabling important clinical assessment. Here, the authors present a molecular gold nanocluster NIR-II fluorescent imaging probe and demonstrate its utility to visualise draining lymph nodes in breast and colon cancer mouse models.

Isolated tumour cells in a sentinel lymph node of apparent early-stage ovarian cancer: Ultrastaging of all other 27 lymph nodes

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Sentinel node is a promising possibility for retroperitoneal lymphatic staging in apparently early ovarian cancer.

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We describe a patient with Isolated tumor cells (ITCs) in one sentinel node with all the other nodes negative at ultrastaging.

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It is likely that the technique of sentinel node in early ovarian cancer is able to identify the real lymphatic drainage of the ovary.

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This report represents a proof of concept in support of the use of sentinel node in apparently early ovarian cancer.

Sentinel lymph node (SLN) biopsy in apparent early-stage ovarian cancer may spare the surgical staging with extensive retroperitoneal dissection and its associated morbidity. However, SLN biopsy in ovarian cancer is still experimental and under investigation. A 46-year-old post-menopausal woman with bilateral apparent stage IC1 endometrioid ovarian cancer underwent surgical staging by SLN biopsy and subsequent comprehensive laparoscopic pelvic and para-aortic lymphadenectomy. Out of 4 SLNs submitted to ultrastaging, one was positive for isolated tumour cells (ITCs). We submitted to ultra-staging all the other 24 pelvic and para-aortic non-SLNs, which were reported negative for disease. This is the first reported case of comprehensive lymphadenectomy after SLN biopsy with universal ultrastaging of all non-SLNs in ovarian cancer. The presence of ITCs in only one SLN, with all other 27 lymph nodes negative at ultrastaging, is consistent with the SLN concept and the assumption of a reliable lymphatic pathway in ovarian cancer.

The Use and Technique of Sentinel Node Biopsy for Skin Cancer

LEARNING OBJECTIVES

After studying this article, the participant should be able to: 1. Understand the indications for and prognostic value of sentinel lymph node biopsy in skin cancer. 2. Learn the advantages and disadvantages of various modalities used alone or in combination when performing sentinel lymph node biopsy. 3. Understand how to perform sentinel lymph node biopsy in skin cancer patients.

SUMMARY

Advances in technique used to perform sentinel lymph node biopsy to assess lymph node status have led to increased accuracy of the procedure and improved patient outcomes.

Sentinel lymph node detection by combining nonradioactive techniques with contrast agents: State of the art and prospects

The status of sentinel lymph nodes (SLNs) has a substantial prognostic value because these nodes are the first place where cancer cells accumulate along their spreading route. Routine SLN biopsy ("gold standard") involves peritumoral injections of radiopharmaceuticals, such as technetium-99m, which has obvious disadvantages. This review examines the methods used as "gold standard" analogs to diagnose SLNs. Nonradioactive preoperative and intraoperative methods of SLN detection are analyzed. Promising photonic tools for SLNs detection are reviewed, including NIR-I/NIR-II fluorescence imaging, photoswitching dyes for SLN detection, in vivo photoacoustic detection, imaging and biopsy of SLNs. Also are discussed methods of SLN detection by magnetic resonance imaging, ultrasonic imaging systems including as combined with photoacoustic imaging, and methods based on the magnetometer-aided detection of superparamagnetic nanoparticles. The advantages and disadvantages of nonradioactive SLN-detection methods are shown. The review concludes with prospects for the use of conservative diagnostic methods in combination with photonic tools.

A photoacoustic finder fully integrated with a solid-state dye laser and transparent ultrasound transducer

The standard-of-care for evaluating lymph node status in breast cancers and melanoma metastasis is sentinel lymph node (SLN) assessment performed with a handheld gamma probe and radioisotopes. However, this method inevitably exposes patients and physicians to radiation, and the special facilities required limit its accessibility. Here, we demonstrate a non-ionizing, cost-effective, handheld photoacoustic finder (PAF) fully integrated with a solid-state dye laser and transparent ultrasound transducer (TUT). The solid-state dye laser handpiece is coaxially aligned with the spherically focused TUT. The integrated finder readily detected photoacoustic signals from a tube filled with methylene blue (MB) beneath a 22 mm thick layer of chicken tissue. In live animals, we also photoacoustically detected both SLNs injected with MB and subcutaneously injected melanomas. We believe that our radiation-free and inexpensive PAF can play a vital role in SLN assessment.

Sentinel Lymph Node Mapping in Endometrial Cancer: A Comprehensive Review

Endometrial cancer (EC) is known as a common gynecological malignancy. The incidence rate is on the increase annually. Lymph node status plays a crucial role in evaluating the prognosis and selecting adjuvant therapy. Currently, the patients with high-risk (not comply with any of the following: (1) well-differentiated or moderately differentiated, pathological grade G1 or G2; (2) myometrial invasion< 1/2; (3) tumor diameter < 2 cm are commonly recommended for a systematic lymphadenectomy (LAD). However, conventional LAD shows high complication incidence and uncertain survival benefits. Sentinel lymph node (SLN) refers to the first lymph node that is passed by the lymphatic metastasis of the primary malignant tumor through the regional lymphatic drainage pathway and can indicate the involvement of lymph nodes across the drainage area. Mounting evidence has demonstrated a high detection rate (DR), sensitivity, and negative predictive value (NPV) in patients with early-stage lower risk EC using sentinel lymph node mapping (SLNM) with pathologic ultra-staging. Meanwhile, SLNM did not compromise the patient’s progression-free survival (PFS) and overall survival (OS) with low operative complications. However, the application of SLNM in early-stage high-risk EC patients remains controversial. As revealed by the recent studies, SLNM may also be feasible, effective, and safe in high-risk patients. This review aims at making a systematic description of the progress made in the application of SLNM in the treatment of EC and the relevant controversies, including the application of SLNM in high-risk patients.

Laparoscopic Probe for Sentinel Lymph Node Harvesting using Magnetic Nanoparticles

OBJECTIVE

Sentinel lymph node harvesting is an essential step in the surgical treatment of a growing number of malignancies. Various techniques are available to facilitate this purpose. The present study reports a new laparoscopic technique for lymph node harvesting using magnetic nanoparticles containing a superparamagnetic iron-oxide core and dextran coating. This study assesses the clinical relevance of the prototype and provides input for further technological development on the way to clinical implementation.

METHODS

A laparoscopic differential magnetometer prototype was built, utilizing a nonlinear detection principle (differential magnetometry) for magnetic identification of lymph nodes. The iron content sensitivity, depth & spatial sensitivity, and angular sensitivity were analyzed to investigate clinical options.

RESULTS

The minimum detectable amount of iron was 9.8 g at a distance of 1 mm. The detection depth was 5, 8, and 10 mm for samples containing 126, 252, and 504 g iron, respectively. The maximum lateral detection distance was 5, 7, and 8 mm for samples containing 126, 252, and 504 g iron, respectively. A sample containing 504 g iron was detectable at all angulations assessed (0, 30, 60 and 90).

CONCLUSION

The laparoscopic differential magnetometer demonstrates promising results for further investigation and development towards laparoscopic lymph node harvesting using magnetic nanoparticles.

SIGNIFICANCE

The laparoscopic differential magnetometer facilitates a novel method for sentinel lymph node harvesting, which helps to determine prognosis and treatment of cancer patients.

Neck Dissections Based on Sentinel Lymph Node Navigation Versus Elective Neck Dissections in Early Oral Cancers: A Randomized, Multicenter, and Noninferiority Trial

PURPOSE

This study aimed to compare patients with early oral cavity squamous cell carcinoma (OCSCC) (tumor category [T] 1-2, node-negative, and no distant metastasis) treated with traditional elective neck dissection (ND) with those managed by sentinel lymph node biopsy (SLNB) using survival and neck function and complications as end points.

METHODS

Sixteen institutions in Japan participated in the study (trial registration number: UMIN000006510). Patients of age ≥ 18 years with histologically confirmed, previously untreated OCSCC (Union for International Cancer Control TNM Classification of Malignant Tumors 7th edition T1-2, node-negative no distant metastasis), with ≥ 4 mm (T1) depth of invasion, were randomly assigned to undergo standard selective ND (ND group; n = 137) or SLNB-navigated ND (SLNB group; n = 134). The primary end point was the 3-year overall survival rate, with a 12% noninferiority margin; secondary end points included postoperative neck functionality and complications and 3-year disease-free survival. Sentinel lymph nodes underwent intraoperative multislice frozen section analyses for the diagnosis. Patients with positive sentinel lymph nodes underwent either one-stage or second-look ND.

RESULTS

Pathologic metastasis-positive nodes were observed in 24.8% (34 of 137) and 33.6% (46 of 134) of patients in the ND and SLNB groups, respectively (P = .190). The 3-year overall survival in the SLNB group (87.9%; lower limit of one-sided 95% CI, 82.4) was noninferior to that in the ND group (86.6%; lower limit 95% CI, 80.9; P for noninferiority < .001). The 3-year disease-free survival rate was 78.7% (lower limit 95% CI, 72.1) and 81.3% (75.0) in the SLNB and ND groups, respectively (P for noninferiority < .001). The scores of neck functionality in the SLNB group were significantly better than those in the ND group.

CONCLUSION

SLNB-navigated ND may replace elective ND without a survival disadvantage and reduce postoperative neck disability in patients with early-stage OCSCC.

Breast Sentinel Lymph Node Frozen Section Practice: An Enterprise Audit as a Guide for Moving Forward

CONTEXT.—

In recent years, there has been a shift to less aggressive surgical management of the axilla in breast cancer. Consequently, sentinel lymph node evaluation by frozen section (FS) has declined. Additionally, there has been an impetus to decrease efforts in identifying small sentinel lymph node metastases.

OBJECTIVES.—

To critically evaluate our enterprise performance in evaluating axillary sentinel lymph nodes submitted for FS prior to considering changes in processing.

DESIGN.—

A retrospective review (August 1, 2017-July 31, 2019) was conducted to identify sentinel and nonsentinel lymph nodes from 1 academic institution and 2 community sites. Cases were evaluated for grossing technique and discordance between FS and permanent section (PS) due to sampling and/or interpretive error. Clinicopathologic features were assessed.

RESULTS.—

Lymph nodes from 426 patients with 432 neoplasms were sent for FS. Serial sectioning at 2-mm intervals was adhered to in 338 of 432 (78.2%). Serial sectioning was significantly lower at the community sites (14 of 60; 23.3%) versus at the academic institution (324 of 372; 87.1%; P < .001). Discordant cases were all false negatives (21 of 432; 4.8%). A total of 7 of 21 false negatives (33.3%) had macrometastatic (>2 mm) disease; of these, 3 were post-neoadjuvant chemotherapy, 3 were neither serially sectioned nor posttherapy, and 1 was a small (0.3-cm) focus. A total of 15 of 16 false negatives due to sampling error were detected on the first permanent section level.

CONCLUSIONS.—

Standard serial sectioning of sentinel lymph nodes at 2-mm intervals resulted in infrequent false negatives due to macrometastatic disease. A single additional permanent section level is reasonable, given adherence to serial sectioning.

Sentinel lymph node biopsy for breast cancer using methylene blue: a new anatomical landmark involving intercostobrachial and medial pectoral nodes

BACKGROUND Sentinel lymph node biopsy (SLNB) using blue dye is becoming popular in Indonesia given that knowledge on new anatomical landmarks involving intercostobrachial and medial pectoral nodes have replaced the need for radioisotope tracers. This study aimed to evaluate the utility of the proposed landmark involving intercostobrachial and medial pectoral nodes to determine axillary lymph node status during SLNB. METHODS A prospective study was conducted involving 55 patients with early-stage breast cancer who had clinically negative lymph nodes (T1–T2, cN0) between 2018 and 2019 at Cipto Mangunkusumo Hospital. During SLNB, methylene blue 1% was injected at the subareolar area to identify intercostobrachial and medial pectoral nodes followed by axillary lymph node dissection (ALND). Histopathological results of sentinel nodes (SNs) were then compared to those of other axillary nodes. RESULTS SNs were identified in 54 patients (98%), 33 (61%) of whom had both intercostobrachial and medial pectoral SNs. Among patients with SNs, there were 1 patient without intercostobrachial SNs, 10 patients without medial pectoral SNs, and 1 patient with medial pectoral SNs but no intercostobrachial SNs. Accordingly, SNs had a negative predictive value (NPV) of 96.77% for axillary metastasis (95% confidence interval = 81.54–99.51), with a false negative rate of 4.7%. No serious adverse events was observed. CONCLUSIONS The high identification rate and NPV, as well as the low false negative rate of the new anatomical landmark involving intercostobrachial and medial pectoral nodes during SLNB, suggest its reliability in determining axillary lymph node status.