Clinical relevance of multiple sentinel nodes in patients with breast cancer

Role of sentinel lymph node biopsy for oral squamous cell carcinoma: Current evidence and future challenges

Sentinel lymph node biopsy (SLNB) has been used across oncological specialties for prognostication, staging, and identification of occult nodal metastasis. Recent studies demonstrated the potential clinical utility of SLNB in oral cavity squamous cell carcinoma (OCSCC). Elective neck dissection is the current standard of care in early management of OCSCC with depth of invasion greater than 2-4 mm; however, majority of patients ultimately do not have nodal disease on final pathology. SLNB is an alternative procedure widely adopted in early cancer management in many oncological subspecialities. Several considerations such as depth of invasion, nodal mapping, histopathology methods, operator variability, postoperative complications, and advancement in preoperative and intraoperative imaging technology can guide the appropriate application to SLNB in OCSCC. The aim of this review is to discuss the current evidence for SLNB in the treatment of early stage OCSCC, imaging technologies that support SLNB procedures, and studies that are currently underway.

Histologic grade has a higher-weighted value than nodal status as predictor of outcome in dogs with cutaneous mast cell tumors and overtly metastatic sentinel lymph nodes

In canine cutaneous mast cell tumors (cMCTs), histologic grade and clinical stage are the most important prognostic factors, with high-grade tumors and metastatic lymph nodes (LNs) significantly influencing the evolution of disease. However, it is uncertain whether histologic grade and clinical stage should be given equal weighting value in patient prognostication and management. Dogs with low- and high-grade cMCTs and at least one overtly metastatic sentinel LN undergoing standardized treatment, consisting of surgical excision of the cMCT, lymphadenectomy and chemotherapy, were retrospectively included. The aim was to determine whether, at the same clinical stage, histologic grade retained prognostic relevance. Sixty dogs were included: 26 had a high-grade cMCT tumor and 34 had a low-grade cMCT. Median follow-up was 367 days (range, 187-748) in the high-grade group, and 1208 days (range, 180-2576) in the low-grade group. Median time to progression was significantly shorter in the high-grade group than in the low-grade group (214 days versus not reached; P<0.001), as well as tumor-specific survival (545 days versus not reached; P<0.001). On multivariable analysis, a high histologic grade and incomplete margins retained prognostic significance for both tumor progression and tumor-specific death. In dogs with cMCT and at least one overtly metastatic LN undergoing multimodal treatment, histologic grade significantly correlated with outcome. Overall prognosis was not unfavorable, even in the high-grade group, further supporting that a multimodal therapeutic approach, addressing primary tumor and sentinel LN, should be offered. Whether chemotherapy should be incorporated in the therapeutic planning of low-grade cMCTs remains to be defined. This article is protected by copyright. All rights reserved.

Sentinel lymph node biopsy with one-step nucleic acid assay relegates the need for preoperative ultrasound-guided biopsy staging of the axilla in patients with early stage breast cancer

Avoiding axillary node clearance in patients with early stage breast cancer and low-burden node-positive axillary disease is an emerging practice. Informing the decision to adopt axillary conservation is examined by comparing routine preoperative axillary staging using ultrasound (AUS) ± AUS biopsy (AUSB) with intraoperative staging using sentinel lymph node biopsy (SLNB) and a one-step nucleic acid cytokeratin-19 amplification assay (OSNA). A single-centre, retrospective cohort study of 1,315 consecutive new diagnoses of breast cancer in 1,306 patients was undertaken in the present study. An AUS ± AUSB was performed on all patients as part of their initial assessment. Patients who had a normal ultrasound (AUS-) or negative biopsy (AUSB-) followed by SLNB with OSNA ± axillary lymph node dissection (ALND), and those with a positive AUSB (AUSB+), were assessed. Tests for association were determined using a χ² and Fisher's Exact test. A total of 266 (20.4%) patients with cT1-3 cN0 staging received 271 AUSBs. Of these, 205 biopsies were positive and 66 were negative. The 684 patients with an AUS-/AUSB-assessment proceeded to SLNB with OSNA. AUS sensitivity and negative predictive value (NPV) were 0.53 [0.44-0.62; 95% confidence interval (CI)] and 0.58 (0.53-0.64, 95% CI), respectively. Using a total tumour load cut-off of 15,000 copies/µl to predict ≥2 macro-metastases, the sensitivity and NPV for OSNA were 0.82 (0.71-0.92, 95% CI) and 0.98 (0.97-0.99, 95% CI) (OSNA vs. AUS P<0.0001). Of the AUSB+ patients, 51% had ≤2 positive nodes following ALND and were potentially over-treated. Where available, SLNB with OSNA should replace AUSB for axillary assessment in cT1-2 cN0 patients with ≤2 indeterminate nodes seen on AUS.

Application of a carbon nanoparticle suspension for sentinel lymph node mapping in patients with early breast cancer: a retrospective cohort study

BACKGROUND

To stage axillary lymph nodes in women with early-stage breast cancer, sentinel lymph node biopsy (SLNB), rather than axillary lymph node dissection (ALND), has been employed. Moreover, different tracer methods have various advantages and disadvantages. In recent years, carbon nanoparticle suspensions (CNSs) have been used as lymph node tracers during surgeries for thyroid cancer, gastric cancer, and colorectal cancer. The study retrospectively analyzed the feasibility and accuracy of CNS for sentinel lymph node (SLN) mapping in patients with early breast cancer.

METHODS

This single-center, retrospective study included breast cancer patients who underwent SLNB from January 1, 2016, to December 31, 2017, in the Department of Breast Cancer, Guangdong General Hospital. All patients received standard SLNB surgery using a CNS tracer.

RESULTS

A total of 332 cases were included in this study. The SLN identification rate was 99.1% (329/332), and the mean number of SLNs was 2.6 (range, 1-6). SLN metastasis was found in 62 (18.8%) cases, of which 90.3% were found to be macrometastases. The sensitivity of SLNB was 95.9% (47/49), with a specificity of 100% (42/42), a positive predictive value of 100% (47/47), a negative predictive value of 95.5% (42/44), and a false-negative rate of 4.1% (2/49).

CONCLUSION

The identification and predictive values of a CNS tracer for SLNB were satisfactory.

Intraoperative prediction of the two axillary lymph node macrometastases threshold in patients with breast cancer using a one-step nucleic acid cytokeratin-19 amplification assay

The aim of the present study was to assess the sensitivity, specificity and practicality of using a one-step nucleic acid amplification (OSNA) assay during breast cancer staging surgery to predict and discriminate between at least 2 involved nodes and more than 2 involved nodes and facilitate the decision to provide axillary conservation in the presence of a low total axillary node tumour burden. A total of 700 consecutive patients, not treated with neo-adjuvant chemotherapy, received intraoperative sentinel lymph node (SLN) analysis using OSNA for cT1-T3 cN0 invasive breast cancer. Patients with at least one macrometastasis on whole-node SLN analysis underwent axillary lymph node dissection (ALND). The total tumour load (TTL) of the macrometastatic SLN sample was compared with the non-sentinel lymph node (NSLN) status of the ALND specimen using routine histological assessment. In total, 122/683 patients (17.9%) were found to have an OSNA TTL indicative of macrometastasis. In addition, 45/122 (37%) patients had NSLN metastases on ALND with a total positive lymph node burden exceeding the American College of Surgeons Oncology Group Z0011 trial threshold of two macrometastatic nodes. The TTL negative predictive value was 0.975 [95% confidence interval (CI), 0.962-0.988]. The area under the curve for the receiver operating characteristic curve was 0.86 (95% CI, 0.81-0.91), indicating that SLN TTL was associated with the prediction (and partitioning) of total axillary disease burden. OSNA identifies a TTL threshold value where, in the presence of involved SLNs, ALND may be avoided. This technique offers objective confidence in adopting conservative management of the axilla in patients with SLN macrometastases.

The predictive value of methylene blue dye as a single technique in breast cancer sentinel node biopsy: a study from Dharmais Cancer Hospital

Background

Axillary lymph node dissection (ALND) has been the standard treatment of breast cancer axillary staging in Indonesia. The limited facilities of radioisotope tracer and isosulfan or patent blue dye (PBD) have been the major obstacles to perform sentinel node biopsy (SNB) in our country. We studied the application of 1% methylene blue dye (MBD) alone for SNB to overcome the problem.

Methods

This prospective study enrolled 108 patients with suspicious malignant lesions or breast cancer stages I–III. SNB was performed using 2–5 cc of 1% MBD and proceeded with ALND. The histopathology results of sentinel nodes (SNs) were compared with axillary lymph nodes (ALNs) for diagnostic value assessments.

Results

There were 96 patients with invasive carcinoma from July 2012 to September 2014 who were included in the final analysis. The median age was 50 (25–69) years, and the median pathological tumor size was 3 cm (1–10). Identification rate of SNs was 91.7%, and the median number of the identified SNs was 2 (1–8). Sentinel node metastasis was found in 53.4% cases and 89.4% of them were macrometastases. The negative predictive value (NPV) of SNs to predict axillary metastasis was 90% (95% CI, 81–99%). There were no anaphylactic reactions, but we found 2 cases with skin necrosis.

Conclusions

The application of 1% MBD as a single technique in breast cancer SNB has favorable identification rates and predictive values. It can be used for axillary staging, but nevertheless the technique should be applied with attention to the tumor size and grade to avoid false negative results.

Magnetic sentinel lymph node biopsy and localization properties of a magnetic tracer in an in vivo porcine model

The standard for the treatment of early non-palpable breast cancers is wide local excision directed by wire-guided localization and sentinel lymph node biopsy (SLNB). This has drawbacks technically and due to reliance upon radioisotopes. We evaluated the use of a magnetic tracer for its localization capabilities and concurrent performance of SLNB using a handheld magnetometer in a porcine model as a novel alternative to the current standard. Ethical approval by the IRCAD Ethics Review Board, Strasbourg (France) was received. A magnetic tracer was injected in varying volumes (0.1-5 mL) subcutaneously into the areolar of the left and right 3rd inguinal mammary glands in 16 mini-pigs. After 4 h magnetometer counts were taken at the injection sites and in the groins. The magnetometer was used to localize any in vivo signal from the draining inguinal lymph nodes. Magnetic SLNB followed by excision of the injection site was performed. The iron content of sentinel lymph nodes (SLNs) were graded and quantified. All excised specimens were weighed and volumes were calculated. Univariate analyses were performed to evaluate correlation. Magnetic SLNB was successful in all mini-pigs. There was a significant correlation (r = 0.86; p < 0.01) between magnetometer counts and iron content of SLNs. Grading of SLNs on both H&E and Perl's staining correlated significantly with the iron content (p = 0.001; p = 0.003) and magnetometer counts (p < 0.001; p = 0.004). The peak counts corresponded to the original magnetic tracer injection sites 4 h after injection in all cases. The mean volume and weight of excised injection site specimens was 2.9 cm(3) (SD 0.81) and 3.1 g (SD 0.85), respectively. Injection of ≥0.5 mL magnetic tracer was associated with significantly greater volume (p = 0.05) and weight of excision specimens (p = 0.01). SLNB and localization can be performed in vivo using a magnetic tracer. This could provide a viable alternative for lesion localization and concurrent SLNB in the treatment of non-palpable breast cancer.

The false-negative rate of sentinel node biopsy in patients with breast cancer: a meta-analysis

BACKGROUND

In sentinel node surgery for breast cancer, procedural accuracy is assessed by calculating the false-negative rate. It is important to measure this since there are potential adverse outcomes from missing node metastases. We performed a meta-analysis of published data to assess which method has achieved the lowest false-negative rate.

METHODS

We found 3,588 articles concerning sentinel nodes and breast cancer published from 1993 through mid-2011; 183 articles met our inclusion criteria. The studies described in these 183 articles included a total of 9,306 patients. We grouped the studies by injection material and injection location. The false-negative rates were analyzed according to these groupings and also by the year in which the articles were published.

RESULTS

There was significant variation related to injection material. The use of blue dye alone was associated with the highest false-negative rate. Inclusion of a radioactive tracer along with blue dye resulted in a significantly lower false-negative rate. Although there were variations in the false-negative rate according to injection location, none were significant.

CONCLUSIONS

The use of blue dye should be accompanied by a radioactive tracer to achieve a significantly lower false-negative rate. Location of injection did not have a significant impact on the false-negative rate. Given the limitations of acquiring appropriate data, the false-negative rate should not be used as a metric for training or quality control.

Current status of sentinel lymph-node biopsy in patients with breast cancer

Axillary node status is the most important prognostic indicator for patients with invasive breast cancer. Sentinel lymph-node biopsy (SLNB) is widely accepted and the preferred procedure for identifying lymph-node metastasis. SLNB allows focused excision and pathological examination of the most likely axillary lymph nodes to receive tumor metastases while avoiding morbidities associated with complete axillary nodal dissection. Since its introduction in the early 1990s, the process of SLNB has undergone continual modification and refinement; however, the procedure varies between institutions and controversies remain. In this review, we examine the technical issues that influence the success of lymph node mapping, discuss the controversies, and summarize the indications and contraindications for axillary node mapping and biopsy in clinical practice.

Sentinel lymph node biopsy in breast cancer guided by indocyanine green fluorescence (Br J Surg 2009; 96: 1289-1294)

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Management of the axilla in patients with breast cancer

This article reviews the changes in management of the axilla in patients with breast cancer in the last decade. It discusses the recent advances, existing controversies and provides evidence-based guidelines for use in clinical practice.Sentinel lymph node (SLN) biopsy has replaced the more morbid axillary lymph node dissection (ALND) and four node sampling for axillary nodal staging. Blue dye guided four node sampling is an acceptable alternative when radioisotope facilities are not available. ALND is reserved for patients with proven axillary lymph node involvement.Preoperative axillary ultrasound and fine-needle aspiration cytology or core biopsy of suspicious lymph nodes reliably identifies around 30% of node positive patients. Intraoperative assessment of the SLN using frozen section or real time molecular assays enables surgeons to perform one stage ALND in node positive patients. For those patients in whom intra-operative SLN assessment is negative, but whose final pathology reveals SLN metastasis, standard treatment has been to perform a completion ALND. Predictive models can be used to identify a lowrisk group of SLN-positive patients in whom routine ALND may not be necessary. In the future, completion ALND for microscopic disease will not be the standard of care but axillary radiotherapy may be an alternative with equal control and less morbidity.

Sentinel lymph node biopsy in breast cancer: the node to recovery

The widespread adoption of sentinel lymph node biopsy to stage the axilla has led to decrease in arm and shoulder morbidity. Sentinel lymph node biopsy is suitable for patients with clinically/radiologically node negative invasive breast cancer and selected patients with DCIS (those with clinical/radiological mass or extensive lesions requiring mastectomy). The combined isotope-blue dye injection technique gives the best results. We inject the isotope intra-dermally preoperatively and blue dye dye subdermally after anesthetic induction into the tumour quadrant peri-areolar tissue. Lymphoscintiscan is not necessary but is useful during the learning phase. Sentinel node biopsy can be performed through a small transverse or vertical axillary incision (∼3 cm) appropriately placed to allow axillary lymph node clearance if needed.

Sentinel lymph node biopsy in breast cancer guided by indocyanine green fluorescence

BACKGROUND

Sentinel lymph node (SLN) biopsy with radioisotope and blue dye has been used successfully for axillary staging in breast cancer. This study evaluated the feasibility of fluorescence detection of SLNs with indocyanine green (ICG) for lymphatic mapping and SLN biopsy.

METHODS

Thirty women with breast cancer had a periareolar injection of ICG for fluorescence detection of SLN using a near-infrared camera. Twenty also received (99m)Tc-labelled sulphur radiocolloid for SLN scintigraphy. All patients underwent axillary lymph node dissection. Detection rate and sensitivity of both methods were the study endpoints.

RESULTS

Visualization of lymphatic vessels by fluorescence detection depended on the dose of ICG. ICG imaging identified SLNs in 29 of 30 women (detection rate 97 per cent). Nineteen of 21 patients had metastatic SLN involvement (sensitivity 90 per cent) with false-negative results in two. Among the 20 patients who had both methods, ICG fluorescence and radiocolloid identified SLNs in 20 and 17 patients respectively. Metastatic lymph nodes were diagnosed in 12 and ten of 13 patients (sensitivity 92 and 77 per cent). False-negative rates were 8 and 23 per cent respectively.

CONCLUSION

ICG fluorescence allowed transcutaneous imaging of lymphatic vessels and SLN detection, thus combining the advantages of radioisotope and blue dye methods.

Molecular assessment of sentinel lymph node in breast cancer management

Sentinel lymph node biopsy (SLNB) is becoming accepted as standard of care for axillary staging in breast cancer. World Health Organization (WHO) re-classification of axillary metastases into macrometastases, micrometastases and individual tumour cells has highlighted the issues of sampling and further histological examination of the initially negative SLNB. Molecular detection of metastatic breast cancer cells in lymph nodes is now available as a commercial kit for intraoperative use and can resolve the sampling issue. Semiquantitative assessment of axillary lymph node tumour burden can now be made using two separate technologies (histology and reverse transcriptase-polymerase chain reaction). The clinical implications of low metastatic axillary lymph node tumour burden are not clear, and future trials need to include molecular data. The consequences of the availability of molecular assessment are reviewed.

Management of the axilla in women with breast cancer: current clinical practice and a new selective targeted approach

BACKGROUND

Axillary nodal status is the most important prognostic factor for patients with breast cancer. Clinical assessment and imaging modalities are not always reliable. Surgical removal and histopathological examination of axillary lymph nodes remain essential methods of staging the axilla. However, the optimal management of the axilla remains uncertain.

METHODS

We performed Medline searches to identify relevant systematic reviews, meta-analysis, and nonrandomized and randomized controlled trials for the past 5 years (up to December 2007), as well as important historical articles and clinical guidelines relating to management of the axilla in women with breast cancer.

RESULTS

Axillary lymph node dissection (ALND) has been the standard surgical approach for many years. It is, however, associated with marked morbidity; survival benefit remains uncertain. Axillary node sampling, widely practiced in the United Kingdom, is a reliable alternative procedure in staging the axilla, with less morbidity. Sentinel lymph node biopsy (SLNB) has become an accurate method for staging the axilla in women with operable, clinically node-negative breast cancer. SLNB alone appears to be a safe and acceptable procedure for patients with uninvolved SLNs. Completion ALND or axillary radiotherapy remains the standard treatment for patients with tumor-involved SLNs. SLNB is associated with less morbidity than ALND. However, long-term follow-up and therapeutic outcomes are being awaited from randomized controlled trials.

CONCLUSIONS

Several procedures are available for staging and treating the axilla. A tailored surgical approach, with careful assessment of risk-benefit and patient preference, is guiding the evolving modern management of the axilla for women with breast cancer.

Optimization of sentinel lymph node biopsy in breast cancer using an operative gamma camera

Background

Sentinel lymph node (SLN) procedure is now a widely accepted method of LN staging in selected invasive breast cancers (unifocal, size ≤ 2 cm, clinically N0, without previous treatment). Complete axillary clearance is no longer needed if the SLN is negative. However, the oncological safety of this procedure remains to be addressed in randomized clinical trials. One main pitfall is the failure to visualize SLN, resulting in incorrect tumor staging, leading to suboptimal treatment or axillary recurrence. Operative gamma cameras have therefore been developed to optimize the SLN visualization and the quality control of surgery.

Case presentation

A 44-year-old female patient with a 14-mm infiltrative ductal carcinoma underwent the SLN procedure. An operative gamma camera was used during and after the surgery. The conventional lymphoscintigraphy showed only one SLN, which was also detected by the operative gamma camera, then removed and measured (9.6 kBq). It was analyzed by frozen sections, showing no cancer cells. During this analysis, the exploration of the axillary area with the operative gamma camera enabled the identification of a second SLN with low activity (0.5 kBq) that conventional lymphoscintigraphy, surgical probe and blue staining had failed to visualize. Histological examination revealed a macrometastasis. Axillary clearance was then performed, followed by a postoperative image proving that no SLN remained. Therefore, the use of the operative gamma camera prevented an under-estimation of staging which would have resulted in a suboptimal treatment for this patient.

Conclusion

This case report illustrates that an efficient operative gamma camera may be able to decrease the risk of false negative rate of the SLN procedure, and could be an additional tool to control the quality of the surgery.

Trial Registration

ClinicalTrials.gov Identifier: NCT00357487

Management of the axilla in women with breast cancer

The approach towards axillary surgery should be selective and flexible, with its management tailored to patient choice and tumour characteristics, and concordant with local practice guidelines and available resources. Sentinel-lymph-node biopsy has been embraced as a standard of care in many centres around the world and has revolutionised management of the axilla during the past decade. Nonetheless, data for long-term outcomes remain scarce, and there are persistent variations in practice and inconsistencies in methodology. An international perspective has been sought on important issues relating to management of the axilla, which includes not only the indications and techniques for sentinel-lymph-node biopsy, but also lymph-node sampling, axillary-lymph-node dissection, and observation alone. In this Review, we initially present an overview, which focuses on biological models of lymphatic networks within the breast and patterns of tumour dissemination. A set of key questions are posed with preliminary comments from the authors, followed by a series of collective viewpoints from experts within several different countries.

A critique of the sentinel node concept

The concept of "the sentinel node" is false. In the axilla, the lymphatic system usually first drains into a group of low axillary nodes (level 1). The validity, as a staging procedure, of a 4 node axillary sample was demonstrated 30 years ago by Prof. Sir Patrick Forrest. Sentinel node biopsy (SNB) should not become the standard of care for all breast cancer patients. All the various options (axillary sampling, SNB, axillary dissection or simply a watchful attitude) are acceptable and to be advised according to the patient's wishes and conditions and to the tumour characteristics. We would also propose the change of the terminology from SNB to "guided axilary sampling" (GAS).

Comparative study of lymphoedema with axillary node dissection versus axillary node sampling with radiotherapy in patients undergoing breast conservation surgery

AIMS

Our aim was to compare the incidence of lymphoedema in two groups of patients undergoing breast conservation surgery; one undergoing axillary sampling and radiotherapy to patients with positive axillary nodes, and the other undergoing axillary clearance.

METHODS

Retrospective review of records of two sequential groups of patients; one undergoing axillary sampling between January 1994 and December 1998 (Group 1) and the other undergoing axillary clearance between January 2000 and December 2002 (Group 2). Both groups had minimum of 2 years follow-up.

RESULTS

Three hundred and twelve patients were included in Group 1 and 194 in Group 2. 2.2% of the patients in Group 1 developed lymphoedema compared to 12.3% in Group 2. This was statistically significant with a P value=0.0001. In the node-positive patients, the incidence of lymphoedema in Group 1 was 6.2% compared to 15.4% in Group 2, although the differences were not statistically significant with P=0.17.

CONCLUSIONS

The incidence of lymphoedema in the axillary sampling group was low, although the differences were less pronounced in the node-positive patients. The effectiveness of radiotherapy as an alternative to full axillary dissection among patients with positive nodes is currently under investigation in randomised controlled trials.

Sentinel lymph nodes in breast cancer after 10 years: rethinking basic principles

New techniques and treatments in medicine occasionally take on a life of their own. Sometimes, an idea's use is inherently obvious from the outset, sometimes not, in which case it becomes technology in search of an application. Identification of sentinel lymph nodes in breast cancer is a combination of these two options: to some extent the technique has been overused and its results overinterpreted. 10 years after the procedure's introduction and general acceptance, a few issues still deserve further discussion despite much published work on this topic. Use of sentinel-lymph-node identification has been extended to other organ systems, yet not all the lessons learned in the breast might apply to other sites. Review of the theory behind the technique and breast cancer experience to date is important. Many of the published controversies about sentinel lymph nodes in breast cancer can be resolved by consideration of the basic ideas underlying the procedure, which is the aim of this Essay.

[Development of technologies for sentinel lymph node biopsy in case of breast cancer]

Sentinel lymph node (SLN) biopsy is now routinely used in breast cancer multidisciplinary management. The combined use of blue dye and lymphoscintigraphy gives the best SLN identification rate. Two different types of probes are available for the SLN procedure: semi-conductor probes and scintillator ones. Moreover, to increase the performances of the SLN procedure, intra-operative gamma cameras have recently been developed. The objectives of our review are to describe these materials to highlight their advantages and drawbacks from the point of view of the surgeon and the physicist.

Does imaging in sentinel node scintigraphic localization add value to the procedure in patients with breast cancer?

Imaging sentinel nodes with pre-operative lymphoscintigraphy effectively assures successful sentinel node identification. However, sentinel nodes are still identified in the majority of image negative patients. Given the logistics and cost required to perform pre-operative lymphoscintigraphy its routine use may not be justified. It may be valuable for surgeons in the learning phase and in obese patients who have increased risk of intra-operative failed localization. A negative pre-operative lymphoscintiscan predicts inability to localize with the hand-held gamma probe. Patients with no 'hot node' on the lymphoscintiscan are more likely to have failed localization using the gamma probe only. Therefore, blue dye should be used along with the gamma probe to optimize the localization rate in these patients.