Effect of lymphatic tumor burden on sentinel lymph node biopsy in breast cancer

Evaluation of Surgical Aid of Methylene Blue in Addition to Intraoperative Gamma Probe for Sentinel Lymph Node Extirpation in 116 Canine Mast Cell Tumors (2017-2022)

Methylene Blue (MB) is combined with radiopharmaceutical for intraoperative sentinel lymph node (SLN) mapping, but its role during SLN extirpation has not been investigated yet in veterinary medicine. The aim of this study was to assess whether MB increased surgical detection of SLN beyond the use of intraoperative gamma-probe (IGP) alone in clinically node-negative dogs with mast cell tumors (MCTs) following the detection of sentinel lymphocentrums (SLCs) via preoperative planar lymphoscintigraphy. Dogs enrolled underwent MCT excision and SLC exploration guided by both MB and IGP. Data recorded for each SLN were staining (blue/non-blue), radioactivity (hot/non-hot), and histopathological status (HN0-1 vs. HN2-3). A total of 103 dogs bearing 80 cutaneous, 35 subcutaneous, and 1 mucocutaneous MCTs were included; 140 SLCs were explored, for a total of 196 SLNs removed. Associating MB with IGP raised the SLNs detection rate from 90% to 95%. A total of 44% of SLNs were metastatic: 86% were blue/hot, 7% were only blue, 5% were only hot, and 2% were non-blue/non-hot. All HN3 SLNs were hot. Combining MB with IGP can increase the rate of SLN detection in dogs with MCTs; nonetheless, all lymph nodes identified during dissection should be removed, as they might be unstained but metastatic.

Contrast-enhanced ultrasound-guided sentinel lymph node biopsy in early-stage breast cancer: a prospective cohort study

OBJECTIVE

This study evaluated the identification efficiency of contrast-enhanced ultrasound (CEUS) for sentinel lymph nodes (SLN) to accurately represent the axillary node status in early-stage breast cancer.

METHOD

In total, 109 consecutive consenting patients with clinically node-negative and T1-2 breast cancer were included in this study. All patients received CEUS to identify SLN before surgery, and a guidewire was deployed to locate SLN in those who were successfully explored by CEUS. The patients underwent sentinel lymph node biopsy (SLNB), and the blue dye was used to trace SLN during the surgery. The decision to perform axillary lymph node dissection (ALND) depended on the intraoperative pathological identification of SLN by CEUS (CE-SLN). The concordance rate of pathological status between CE-SLN and dyed SLN was calculated.

RESULT

The CEUS detection rate was 96.3%; CE-SLN failed in 4 patients. Among the remaining 105 successful identifications, 18 were CE-SLN positive by intraoperative frozen section, and one with CE-SLN micrometastasis was diagnosed by paraffin section. No additional lymph node metastases were found in CE-SLN-negative patients. The concordance rate of pathological status between CE-SLN and dyed SLN was 100%.

CONCLUSION

CEUS can accurately represent the status of axillary lymph nodes in patients with clinically node-negative and small tumor burden breast cancer.

Clinical factors associated with failed sentinel lymph node mapping in endometrial cancer

Objective

Sentinel lymph node (SLN) mapping is a highly accurate surgical technique for detecting metastases in endometrial cancer. The objective of this study was to identify clinical factors associated with failed mapping.

Methods

All patients with endometrial cancer undergoing minimally-invasive staging and planned SLN biopsy from 1/1/2017 to 12/31/2020 at a single institution were identified retrospectively. Demographic, clinicopathologic and treatment data were obtained. Data were compared using descriptive statistics. Univariate and multivariable logistic regression were performed to identify predictors of failed mapping.

Results

819 patients were identified with a mean age of 64.6 years (range 26-93) and mean BMI of 35.6 kg/m² (range 18-68). Most (88.5 %, 725/819) had early-stage disease and endometrioid histology (82.3 %, 674/819). A majority (74.2 %, 608/819) had successful bilateral mapping, and 54 (6.6 %) had unsuccessful bilateral mapping. Increasing BMI was significantly associated with unsuccessful bilateral mapping: patients with BMI > 30 were more likely to have unsuccessful SLN mapping (p = 0.033). Among patients with known lymph node status (799/819), patients with macrometastases and micrometastases were more likely to have failed bilateral mapping compared to those with negative SLNs or isolated tumor cells (p = 0.013). On multivariable analysis, higher BMI and histology were associated with failed bilateral mapping (OR = 1.023, 95 % CI (1.005, 1.041) and OR = 1.678, 95 % CI (1.177, 2.394), respectively).

Conclusion

SLN mapping has a high success in patients undergoing minimally-invasive surgical staging for endometrial cancer. Increasing BMI, high risk histology, and lymph node metastases are risk factors for failed mapping.

Establishing a prediction model of axillary nodal burden based on the combination of CT and ultrasound findings and the clinicopathological features in patients with early-stage breast cancer

Background

Axillary lymph node (ALN) management in early-stage breast cancer (ESBC) patients has become less invasive during the past decades. Here, we tried to explore whether high nodal burden (HNB) in ESBC patients could be predicted preoperatively, so as to avoid unnecessary sentinel lymph node biopsy (SLNB).

Methods

The clinicopathological and imaging data of patients with early invasive breast cancer (cT_1-2N₀M₀) were analyzed retrospectively. Univariate and multivariate analyses were performed for the risk factors of axillary HNB in ESBC patients, and a risk prediction model of HNB was established.

Results

HNB was identified in 105 (8.0%) of 1,300 ESBC patients. Multivariate analysis showed that estrogen receptors (ER) status, human epidermal growth factor receptor 2 (HER2) status, number of abnormal lymph nodes (LNs) on computed tomography (CT), and axillary score on ultrasound (US) were the risk factors of HNB (all P<0.05). The area under the receiver operating characteristic (ROC) curve in the prediction model was 0.914, with the sensitivity being 85.7% and the specificity being 82.4%. The calibration curve showed that the prediction model had good performance.

Conclusions

As a valuable tool for predicting HNB in ESBC patients, this newly established model helps clinicians to make reasonable axillary surgery decisions and thus avoid unnecessary SLNB.

Determining agreement between preoperative computed tomography lymphography and indocyanine green near infrared fluorescence intraoperative imaging for sentinel lymph node mapping in dogs with oral tumours

Lymphatic drainage from the head and neck is variable with significant crossover, therefore sentinel lymph node (SLN) mapping can help ensure the appropriate lymph node(s) are sampled. To improve sensitivity, SLN mapping utilizing multiple modalities and a combination of preoperative computed tomography lymphography (CTL) and intraoperative near infrared fluorescence imaging (NIRF) with indocyanine green (ICG) +/- methylene blue (MB) dye has been suggested. The aim of this study was to describe a method for intraoperative ICG lymphography and determine agreement for SLN detection using preoperative CTL and intraoperative ICG NIRF + MB lymphography (IOL) in dogs with oral tumours. Fourteen client-owned dogs were included. All dogs had preoperative CTL with iodinated contrast and intraoperative IOL with an exoscope. Lymph nodes with CTL contrast-enhancement, blue staining or fluorescence were considered sentinel. The overall SLN identification rate was 100% when CTL and IOL were combined. A total of 57 SLNs were identified. Indocyanine green NIRF identified a greater proportion of SLNs (91%; 52/57) compared with MB (50.8%; 29/57) and CTL (42.1%; 24/57). Eighteen SLNs were identified by all three modalities with a fair level of agreement using Fleiss kappa. These findings suggest a combination of preoperative CTL with intraoperative SLN mapping techniques may greatly improve the ability to accurately detect the SLN in dogs with oral tumours.

Size-dependent lymphatic uptake of nanoscale-tailored particles as tumor mass increases

Aim:

To investigate the size-dependent lymphatic uptake of nanoparticles in mice with rapidly growing syngeneic tumors.

Materials & methods:

Mice were inoculated subcutaneously with EL4 lymphoma cells and on day 5 or day 6 of tumor growth, injected peritumorally with either 29 nm or 58 nm of ultra-small superparamagnetic iron oxide nanoparticles. Twenty-four hours later the animals were imaged using MRI.

Results & conclusion:

The larger of the two particles can only be detected in the lymph node when injected in animals with 6-day-old tumors while the 29 nm ultra-small superparamagnetic iron oxide nanoparticle is observed on both time points. Tumor mass greatly impacts the size of particles that are transported to the lymph nodes.

This study aims to improve the way the spreading of certain forms of cancer is detected. The method, known as sentinel lymph node detection, locates and removes the first lymph node that drains the tumor to examine it for cancer cells. The authors want to improve the way this is done by using a new contrast agent based on nanoparticles. Two different sizes of particles were injected around the implanted tumors in mice and imaged with MRI. The results indicate that the mass of the tumor plays a crucial role in the transport of nanoparticles to the lymph node.

Optimizing retention of multimodal imaging nanostructures in sentinel lymph nodes by nanoscale size tailoring

This study investigates the retention of different sized ultra-small superparamagnetic iron oxide nanoparticles (USPIOs) in lymph nodes of healthy rats, after subcutaneous injection. Three distinct sizes (15, 27 and 58 nm) of USPIOs were synthesized by only varying the thickness of the polymer coating surrounding the 10 nm cores. Particles were injected on the dorsal side of the hind paw of rats and the uptake in the popliteal, inguinal and iliac lymph nodes was monitored. The data reveal that the 15 nm particle accumulates more rapidly and to a higher amount in the first lymph node than the two larger particles. A clear contrast between the first and second lymph nodes could be detected indicating that even the rather small difference in particle size (15-58 nm) tested has significant effects on the retention of USPIOs in the lymph nodes.

FROM THE CLINICAL EDITOR

From the Clinical Editor: In this study, the size-dependence of USPIO particles is studied from the standpoint of their accumulation characteristics in lymph nodes. The authors conclude that the smaller particles accumulated faster and at a higher concentration than the two larger sizes studied.

Results of a national training programme in sentinel lymph node biopsy for breast cancer

BACKGROUND

New Start, a structured, validated, multidisciplinary training programme in sentinel lymph node biopsy (SLNB), was established to allow the introduction and rapid transfer of appropriate knowledge and technical skills to ensure safe and competent practice across the UK.

METHODS

Multidisciplinary teams attended a theory/skills laboratory course, following which they performed 30 consecutive SLNBs, either concurrently with their standard axillary staging procedure (training model A) or as stand-alone SLNB (training model B). SLNB was performed according to a standard protocol using the combined technique of isotope ((99m) Tc-labelled albumin colloid) and blue dye. An accredited New Start trainer mentored the first five procedures in the participant's hospital, or all 30 if stand-alone. Validation standards for model A and B were a localization rate of at least 90 per cent. In addition, for model A only, in which a minimum of ten patients were required to be node-positive, a false-negative rate (FNR) of 10 per cent or less was required.

RESULTS

From October 2004 to December 2008, 210 SLNB-naive surgeons, in 103 centres, performed 6685 SLNB procedures. The overall sentinel lymph node (SLN) localization rate was 98·9 (95 per cent confidence interval 98·6 to 99·1) per cent (6610 of 6685) and the FNR 9·1 (7·9 to 10·5) per cent (160 of 1757). The FNR was related to nodal yield, ranging from 14·8 per cent for one node and declining to 9·7, 6·6, 4·7 and 4·1 per cent for two, three, four and more than four SLNs respectively. No learning curve was identified for localization or FNR.

CONCLUSION

The programme successfully trained a wide range of UK breast teams to perform safe SLNB and suggested that a standard injection protocol and structured multidisciplinary training can abolish learning curves.

Visualisation of sentinel lymph node with indium-based near infrared emitting Quantum Dots in a murine metastatic breast cancer model

Due to its non-invasiveness, high temporal resolution and lower cost, fluorescence imaging is an interesting alternative to the current method (blue dye and radiocolloid) of sentinel lymph node (SLN) mapping in breast cancer. Near-infrared (NIR) emitting cadmium-based Quantum Dots (QDs) could be used for this purpose; however, their wide application is limited because of the toxicity of heavy metals composing the core. Our recent work demonstrated that indium-based QDs exhibit a weak acute local toxicity in vivo compared to their cadmium-based counterparts. In the present study we confirmed the weak toxicity of CuInS(2)/ZnS QDs in different in vitro models. Further in vivo studies in healthy mice showed that In-based QDs could be visualised in SLN in a few minutes after administration with a progressive increase in fluorescence until 8 h. The quantity of indium was assessed in selected organs and tissues by inductively coupled plasma - mass spectroscopy (ICP-MS) as a function of post-injection time. QD levels decrease rapidly at the injection point in the first hours after administration with a parallel increase in the lymph nodes and to a lesser extent in the liver and spleen. In addition, we observed that 3.5% of the injected indium dose was excreted in faeces in the first 4 days, with only trace quantities in the urine. Metastatic spread to the lymph nodes may hamper its visualisation. Therefore, we further performed non-invasive fluorescence measurement of QDs in SLN in tumour-bearing mice. Metastatic status was assessed by immunohistology and molecular techniques and revealed the utmost metastatic invasion of 36% of SLN. Fluorescence signal was the same irrespective of SLN status. Thus, near-infrared emitting cadmium-free QDs could be an excellent SLN tracer.

Sentinel lymph node biopsy after previous axillary surgery: A review

BACKGROUND

The utility of axillary lymph node dissection (ALND) in the management of breast cancer is currently under close scrutiny. At primary diagnosis the use of sentinel lymph node biopsy (SLNB) has restricted ALND for proven nodal disease, however the management of the axilla at local (in-breast) relapse is less clearly defined with many undergoing routine ALND. This review examines the role of SLNB in the re-operative setting with the objective of developing an axillary management algorithm for use at in-breast local relapse, and restricting ALND to node-positive recurrent cancers.

METHODS

We reviewed published reports of SLNB at local relapse in women who had previously undergone axillary surgery either as lymph node biopsy, SLNB, axillary sampling (AS) or axillary lymph node dissection (ALND).

RESULTS

There have been no randomised trials. Six reports with 327 cases were identified; of which 61% (199/327) had previous SLNB or ALND with <9 nodes removed. There was an overall successful sentinel lymph node (SLN) localisation at re-operation of 69% (227/327), range of 51-100%. In patients who have previously had limited axillary surgery (<9 nodes removed), the rate of successful SLN localisation was 83% (165/199), range of 68-100% and 142/165 (86%, range 80-100%) were node negative. In these highly selected patients no axillary recurrences were noted in those who had a negative SLN at re-operation after 26-46 months follow up.

CONCLUSION

SLNB at in-breast relapse is feasible and safe with successful localisation related to the extent of previous axillary surgery.

Quantitative imaging of lymphatic function with liposomal indocyanine green

Lymphatic vessels play a major role in cancer progression and in postsurgical lymphedema, and several new therapeutic approaches targeting lymphatics are currently being developed. Thus, there is a critical need for quantitative imaging methods to measure lymphatic flow. Indocyanine green (ICG) has been used for optical imaging of the lymphatic system, but it is unstable in solution and may rapidly enter venous capillaries after local injection. We developed a novel liposomal formulation of ICG (LP-ICG), resulting in vastly improved stability in solution and an increased fluorescence signal with a shift toward longer wavelength absorption and emission. When injected intradermally to mice, LP-ICG was specifically taken up by lymphatic vessels and allowed improved visualization of deep lymph nodes. In a genetic mouse model of lymphatic dysfunction, injection of LP-ICG showed no enhancement of draining lymph nodes and slower clearance from the injection site. In mice bearing B16 luciferase-expressing melanomas expressing vascular endothelial growth factor-C (VEGF-C), sequential near-IR imaging of intradermally injected LP-ICG enabled quantification of lymphatic flow. Increased flow through draining lymph nodes was observed in mice bearing VEGF-C-expressing tumors without metastases, whereas a decreased flow pattern was seen in mice with a higher lymph node tumor burden. This new method will likely facilitate quantitative studies of lymphatic function in preclinical investigations and may also have potential for imaging of lymphedema or improved sentinel lymph detection in cancer.

Nano-imaging of the lymph network structure with quantum dots

Sentinel lymph node diagnosis contributes to operative strategy in cancer surgery. During lymph node metastasis, cancer cells first reach the sentinel lymph node (SLN) via lymph flow. To perform SLN biopsy effectively, it is important that cancer cells are detected with high sensitivity in SLN connected to the tumor site. Here we present a method to visualize a high-risk area in the SLN for lymph node metastasis with a high degree of accuracy. Quantum dots (QDs), bright fluorescent nanoparticles, were endoscopically injected into the gastrointestinal wall of pigs, and their signal was specifically detected in the SLN with a laparoscopic device. Single-particle imaging under a confocal microscope showed that the QDs were distributed heterogeneously in the SLN and that their distribution marked the inflow locus of afferent lymphatic vessels where lymph node metastasis begins. Moreover, we developed a method using cellular marker conjugated QDs that visualizes specific cells in SLNs, suggesting that this method can be applied for the detection of cancer cells in sentinel lymph nodes using tumor-specific-molecular conjugated QDs. These results show that our method might significantly increase the detection rate of cancer metastasis in SLNs.

Sentinel node imaging in breast cancer using superficial injections: technical details and observations

INTRODUCTION

Sentinel lymph node (SLN) biopsy is the evolving standard of care for the management of early breast cancer. Accurate identification of the SLN is paramount for success of this procedure. Various techniques are described for SLN identification, but the superficial injection techniques, advocated by the UK National Training Programme (NEW START), are validated, reproducible and rapid. Pre-operative lymphoscintigraphy provides a road map for the surgeon and requires a reporting template.

METHODS

As one of the NEW START training institutions in the UK practising this technique, we reviewed a mature series of 100 unselected, consecutive SLN lymphoscintigraphy procedures. We correlated the imaging, operative and pathology findings and have provided technical details of the technique and a template for reporting SLN lymphoscintigrams.

RESULTS

The SLN localisation rate was 99% with one failed imaging. Seven patients required delayed imaging. The mean activity of the radiocolloid injected was 14.4MBq (range 8.3-23 MBq). The SLNs were visualised in the ipsilateral axilla in 98 images, intramammary in 3, and internal mammary in 1. A mean of 1.35 nodes were classified as 'True' SLNs on imaging criteria. Intra-operatively, a mean of 1.91 SLNs were excised. 32 of 116 hot and blue nodes, 7 of 15 only blue nodes, 13 of 47 only hot and 7 of 13 parasentinel nodes harboured metastases.

CONCLUSION

The NEW START recommended, combined superficial injection techniques, have high localisation rates. Pre-operative sentinel node imaging is recommended and a template for reporting is provided.

Identification and biologic significance of micrometastases in axillary lymph nodes in patients with invasive breast cancer

CONTEXT

The presence or absence of metastases in axillary lymph nodes is one of the most important prognostic factors for patients with breast cancer. During the past decade sentinel lymph node (SLN) biopsy has been increasingly adopted as a minimally invasive staging alternative to complete axillary node dissection.

OBJECTIVE

Sentinel lymph nodes are more likely to contain metastases than non-SLNs. In routine clinical practice SLNs are assessed by diverse methodologies including multiple sectioning, immunohistochemical staining, and molecular diagnostic tests. Despite the lack of standard histopathologic protocols during the years detailed evaluation of SLNs has resulted in an increased detection of small (micro) metastases.

DATA SOURCES

Breast cancer with micrometastases constitutes a heterogenous group of tumors with variable clinical outcome regarding the risk of additional metastases in the remaining axillary lymph nodes and to patients' survival.

CONCLUSION

The clinical significance of micrometastases has been subject to great controversy in patients with breast cancer. In this review we highlight controversies regarding micrometastases especially in relation to SLNs.

One-day or two-day procedure for sentinel node biopsy in melanoma?

PURPOSE

We compared the outcome of a 1-day and a 2-day sentinel node (SN) biopsy procedure, evaluated in terms of lymphoscintigraphic, surgical and pathological findings.

METHODS

We studied 476 patients with melanoma from two melanoma centres using static scintigraphy and blue dye. A proportional odds model was used for statistical analysis.

RESULTS

The number of SNs visualized at scintigraphy increased significantly with time from injection to scintigraphy and activity left in the patient at scintigraphy, and depended on the melanoma location. The number of SNs removed at surgery increased with the number of SNs visualized at scintigraphy and time from injection to surgery. The frequency of nodal metastasis increased with increasing thickness and Clark level of the melanoma, and was highest for two SNs visualized at scintigraphy.

CONCLUSION

This study showed that early vs. late imaging and surgery do make a difference on the outcome of the SN procedure and confirmed the importance of the scintigraphic visualization of all true SNs.

[Systematic neck dissection in squamous cell carcinoma of the oral cavity]

OBJECTIVES

To evaluate the neck control after prior surgical management of patients with squamous cell carcinoma of the oral cavity and to quantify the ratio of patients among whom neck dissection did not have a real therapeutic value. To discuss the usefulness of the sentinel node biopsy in this group of patients.

METHOD

Retrospective analysis of patients with epidermoid carcinoma of the oral cavity who had systematically a neck dissection.

RESULTS

Thirty-nine files of patients have been processed. We found 45% patients classified pN0 (among whom about one half where classified pT4). With a mean follow-up of 19 months, we did not find any cervical lymph node relapse. Five patients died (13.5%) without any cervical disease.

CONCLUSION

The systematic cervical lymph node dissection remains the most effective means to obtain the neck control of squamous cell cancers of the oral cavity. It however was applied without therapeutic value for 45% of the patients of this series. The validation of the sentinel node concept as a method of cervical staging should make it possible to avoid this surgical procedure in more than one third of the cases.

Impact of Patient- and Disease-Specific Factors on SLNB in Breast Cancer Patients. Are Current Guidelines Justified?

BACKGROUND

The evidence on which to base guidelines for sentinel lymph node biopsy (SLNB) in breast cancer is still limited. In order to facilitate the further implementation of renewed guidelines, we evaluated patient- and disease-specific factors for their impact on the results of SLNB.

MATERIALS AND METHODS

Prospective data acquisition from patients undergoing surgery for primary invasive breast cancer was performed. All patients underwent SLNB using the radiocolloid or the combined technique. The association of patient- and disease-specific factors to detection rate and false-negative rate was calculated using univariate and multivariate analyses (P < 0.05 considered as significant). Calculation of the false-negative rate was based on patients who underwent a backup axillary dissection.

RESULTS

Among 455 consecutively enrolled patients, a significant inverse association to the detection rate was found for extracapsular extension of non-SLN metastases, body mass index (BMI), number of involved lymph nodes, pT category, tumor size, and age. A significant association to the false-negative rate to identify macrometastases was found for pT category, tumor size, and grading. Other factors, such as prior surgery, multicentric tumor growth, or vascular invasion, showed no influence. A cut-point analysis revealed that a tumor size of 2 cm separated the collective of patients with the highest significance in regard to the false-negative rate (9% vs. 25%).

CONCLUSION

Our results indicate that SLNB can be safely used in elderly and obese patients with multicentric tumors and those having undergone prior surgery for benign breast disease. However, the method should be applied with caution in patients with tumors larger than 2 cm.

Factors affecting failed localisation and false-negative rates of sentinel node biopsy in breast cancer--results of the ALMANAC validation phase

BACKGROUND

Despite the widespread application of sentinel lymph node biopsy (SLNB) for early stage breast cancer, there is a wide variation in reported test performance characteristics. A major aim of this prospective multicentre validation study was to quantify detection and false-negative rates of SLNB and evaluate factors influencing them.

METHODS

Eight-hundred and fourty-two patients with clinically node-negative breast cancer underwent SLNB according to a standardised protocol that used a combination of radiopharmaceutical 99mTc-albumin colloid and Patent Blue V dye. SLNB was followed by standard axillary treatment at the same operation in all patients.

RESULTS

Sentinel lymph nodes (SLNs) were identified in 803 (96.1%) of 836 evaluable cases. The median number of SLNs removed per patient was 2 (range 1-9). There were 19 false negatives, resulting in a sensitivity of 263/282 (93.3%) and accuracy 782/803 (97.6%). SLNs were successfully identified by blue dye in 698 (85.6%), by isotope in 698 (85.6%), and by the combination of blue dye and isotope in 782 (96.0%) of 815 patients. Among 276 node positive patients, one or more positive SLNs were identified by blue dye in 251 (90.9%), by isotope in 246 (89.1%) and by the combination of blue dye and gamma probe in 258 (93.5%). Obesity, tumor location other than upper outer quadrant and non-visualisation of SLNs on the pre-operative lymphoscintiscan were significantly associated with failed localisation (p<0.001, p=0.008, p<0.001, respectively). The false-negative rate in patients with grade 3 tumors was 9.6%, compared with 4.7% in those with grade 2 tumors (p=0.022). The false-negative rate in patients who had one SLN harvested was 10.1%, compared with 1.1% in those who had multiple SLNs (three or more) removed (p=0.010).

CONCLUSION

SLNB can accurately determine whether axillary metastases are present in patients with early stage breast cancer with clinically negative axillary nodes. Both success and accuracy of SLNB are optimised by the combined use of blue dye and isotope. SLNB success decreases with increasing body mass, tumor location other than the upper outer quadrant and non-visualisation of hot nodes on the pre-operative lymphoscintiscan. This study demonstrates reduction in the predictive value of a negative SLNB in grade 3 tumors.