Preoperative Axillary Staging Research Articles

Pre-operative axillary staging: should core biopsy be preferred to fine needle aspiration cytology?

ObjectiveTo determine the diagnostic accuracy of ultrasound guided fine needle aspiration (FNA) cytology and core needle biopsy (CNB) of axillary lymph nodes pre-operatively in newly diagnosed operable primary breast cancer.MethodsAn observational study for all patients who underwent pre-operative FNA cytology or CNB during September 2013–August 2014 was conducted at our institution (County Hospital, Stafford, UK). The accuracy of pre-operative axillary staging was compared to the post-operative histology. For this sensitivity, specificity, positive predictive value (PPV) and negative predictive values (NPV) were calculated.ResultsA total of 81 consecutive patients were evaluated by axillary ultrasound. Patients identified with potentially abnormal axillary lymph nodes underwent definitive surgery. Seven patients had positive cytology/histology who did not undergo definitive surgery and were excluded (N = 74) from the study. CNB had a sensitivity of 100% versus 72% (p = 0.006) for FNA cytology. Both had 100% specificity and PPV. The NPV of CNB was 100% versus 72% for FNA cytology. Among 35% of patients that underwent FNA cytology required repeat procedure versus 2.6% of patients who underwent CNB. 0/38 patients that had CNB required a second operation while 7/43 patients with negative FNA cytology had positive lymph nodes identified at sentinel lymph node biopsy (SLNB) requiring surgical re-intervention with axillary node clearance.ConclusionCNB was superior to FNA cytology when interrogating the axilla. We recommend CNB to be adopted routinely in pre-operative axillary staging to reduce surgical re-intervention.

Abstract P2-01-21: Preoperative axillary ultrasound guided needle sampling in breast cancer: Comparing the sensitivity of fine needle aspiration cytology and core needle biopsy

Abstract Background: Preoperative axillary ultrasound (US) combined with selective US-guided needle sampling (UNS) can be used to identify lymph node metastases. This can inform decisions about neoadjuvant chemotherapy and allow a patient to proceed immediately to axillary lymph node dissection (ALND) thus avoiding an extra sentinel node biopsy (SNB) procedure. We acknowledge the landmark ACOSOG Z0011 trial showing a subgroup of patients (T1-2) undergoing breast conserving surgery and whole-breast radiotherapy in which ALND can safely be omitted if they have minimal nodal disease burden. For these patients the utility of UNS may be limited if the surgeon has modified their practice according to the trial. For patients not fitting the Z0011 trial criteria, preoperative UNS remains important. Previous studies comparing the sensitivity of axillary US-guided fine needle aspiration cytology (FNA) and core needle biopsy (CNB) have been small and a meta-analysis has not shown a difference in sensitivity1. Our aim was to directly compare the sensitivity of the two techniques. Method: Patients with macrometastatic nodal involvement that were treated at a tertiary referral centre between January 2013 and December 2014 were retrospectively identified from pathology records. Preoperative UNS had been performed by one of eight Consultant Radiologists with the sampling method being according to each individual radiologist's preference. The result of the first UNS performed on each patient was compared to post-operative histopathology results. Patients who had undergone previous axillary surgery or any part of their investigations/treatment at another unit were excluded. Results: A total of 101 CNBs and 181 FNAs were performed in 282 patients. There were 78 true positive CNBs and 96 true positive FNAs. US-guided CNB was therefore more sensitive than US-guided FNA (77.2% vs. 53.0%, p=<0.001). Two non-diagnostic CNBs and eight non-diagnostic FNAs were performed. Five patients in the CNB group were correctly identified preoperatively as having isolated tumour cells (ITCs) or micrometastatic disease only in their axillary lymph nodes and were therefore triaged to SNB rather than ALND. A single haematoma requiring non-operative management was recorded in the CNB group. Conclusion: US-guided CNB of the axilla is more sensitive than US-guided FNA and is a safe technique in experienced hands. We also highlight the additional potential benefit (whilst accepting the possibility of sampling error) of CNB over FNA in assisting the multidisciplinary planning of axillary surgery in patients who are found to have ITCs or micrometastatic disease only during their preoperative axillary staging.

Preoperative ultrasound staging of the axilla make’s peroperative examination of the sentinel node redundant in breast cancer: saving tissue, time and money

ObjectiveTo evaluate the role of preoperative axillary staging with ultrasound (US) and fine needle aspiration cytology (FNAC). Can we avoid intraoperative sentinel lymph node (SLN) examination, with an acceptable revision rate by preoperative staging? DesignThis study is based on the retrospective data of 336 patients that underwent US evaluation of the axilla as part of their staging. A FNAC biopsy was performed when abnormal lymph nodes were visualized. Patients with normal appearing nodes on US or a benign diagnostic biopsy had removal of the SLNs without intraoperative pathological examination. We calculated the sensitivity, specificity and accuracy of US/FNAC in predicting the necessity of an axillary lymphadenectomy. Subsequently we looked at the total cost and the operating time of 3 models. Model A is our study protocol. Model B is a theoretical protocol based on the findings of the Z0011 trial with only clinical preoperative staging and in Model C preoperative staging and intraoperative pathological examination were both theoretically done.sentinel node, staging, ultrasound, preoperative axillary staging, FNAC, axilla ResultsThe sensitivity, specificity and accuracy are respectively 0.75 (0.66–0.82), 1.00 (0.99–1.00) and 0.92 (0.88–0.94). Only 26 out of 317 (8.2%) patients that successfully underwent staging needed a revision. The total cost of Model A was 1.58% cheaper than Model C and resulted in a decrease in operation time by 9,46%. The benefits compared with Model B were much smaller. ConclusionPreoperative US/FNAC staging of the axillary lymph nodes can avoid intraoperative examination of the sentinel node with an acceptable revision rate. It saves tissue, reduces operating time and decreases healthcare costs in general.

The accuracy of preoperative axillary nodal staging in primary breast cancer by ultrasound is modified by nodal metastatic load and tumor biology

Background The outcome of axillary ultrasound (AUS) with fine-needle aspiration biopsy (FNAB) in the diagnostic work-up of primary breast cancer has an impact on therapy decisions. We hypothesize that the accuracy of AUS is modified by nodal metastatic burden and clinico-pathological characteristics. Material and methods The performance of AUS and AUS-guided FNAB for predicting nodal metastases was assessed in a prospective breast cancer cohort subjected for surgery during 2009–2012. Predictors of accuracy were included in multivariate analysis. Results AUS had a sensitivity of 23% and a specificity of 95%, while AUS-guided FNAB obtained 73% and 100%, respectively. AUS-FNAB exclusively detected macro-metastases (median four metastases) and identified patients with more extensive nodal metastatic burden in comparison with sentinel node biopsy. The accuracy of AUS was affected by metastatic size (OR 1.11), obesity (OR 2.46), histological grade (OR 4.43), and HER2-status (OR 3.66); metastatic size and histological grade were significant in the multivariate analysis. Conclusions The clinical utility of AUS in low-risk breast cancer deserves further evaluation as the accuracy decreased with a low nodal metastatic burden. The diagnostic performance is modified by tumor and clinical characteristics. Patients with nodal disease detected by AUS-FNAB represent a group for whom neoadjuvant therapy should be considered.

Predictive value of fine needle aspiration biopsy of axillary lymph nodes in preoperative breast cancer staging.

Diagnosis of axillary nodal involvement is significant in the management of breast cancer as well as in predicting prognosis. In this prospective study, we evaluated the efficiency of US-guided fine needle aspiration biopsy (FNAB) in preoperative axillary staging of early breast cancer. Between January 2011 and July 2013, 46 women were prospectively enrolled in the study. Ultrasound guided-FNABs for axillary assessment were performed preoperatively. Cytology results were compared with histopathology reports to determine its sensitivity, specificity, negative and positive predictive value and accuracy. Nineteen cases that had malignant cytology on FNAB also had axillary involvement in axillary lymph node dissection (ALND) without any false-positive results. The sensitivity and specificity of US-guided FNAB were 63.3% and 100%, respectively. US-guided FNAB was accurate in predicting the status of the axilla in 76.1% of patients. Although this technique is favorable due to its minimally invasive nature, it is not as effective as sentinel lymph node biopsy (SLNB) in terms of detecting axillary metastasis preoperatively. The low sensitivity and low accuracy rates decrease the usefulness of the technique. Therefore, it seems that US-guided FNAB alone could not replace SLNB. Nevertheless, combining some other molecular studies may be useful in increasing the technique's sensitivity. These issues should be determined by comprehensive clinical trials.

Is Pre-Operative Axillary Staging with Ultrasound and Ultrasound-Guided Fine-Needle Aspiration Reliable in Invasive Lobular Carcinoma of the Breast?

Axillary ultrasound (US) with US-guided fine-needle aspiration (US-FNA) for suspicious lymph nodes is important for pre-operative staging and planning of surgical management. Invasive lobular carcinoma (ILC) metastases were previously thought to be difficult to detect, but with a limited amount of evidence. This study investigated the ability of US and US-FNA to detect ILC metastases by assessing 142 patients with ILC. The sensitivity of US in detection of metastasis was 52.3%, and US was able to exclude 96% of N2 and N3 axillary metastases. The false-negative rate of US-FNA in detection of metastasis for suspicious lymph nodes on US was 34.8%, and lymph nodes with longer maximal dimensions were associated with false-negative US-FNA results. Multiplicity of breast lesions and maximal cortical thickness ≥3.1 mm of lymph nodes were independently associated with metastasis. Although pre-operative US in ILC can reliably exclude advanced axillary nodal disease, US-FNA results should be carefully interpreted.

Abstract OT3-02-07: Neo-DDRD: A biomarker-driven neoadjuvant feasibility study in breast cancer

Abstract Background Anthracycline-based chemotherapy reduces the risk of early breast cancer recurrence but to date it has not been possible to predict which patients specifically benefit from this treatment. The Almac DDRD assay, a 44 gene signature, has been developed to detect DNA damage response deficiency (DDRD) within breast and other cancer types. The DDRD assay has been shown to predict benefit from DNA damaging chemotherapy in retrospective analyses in neoadjuvant and adjuvant settings (Mulligan et al, JNCI 2014). This pilot study aims to prospectively evaluate the feasibility and utility of this signature in the neoadjuvant setting in breast cancer. It will inform the design of a phase II randomised study where the DDRD assay will be utilised to guide neoadjuvant chemotherapy selection. Study design A single-centre, non-randomised feasibility study of 30 women with a histologically confirmed diagnosis of breast cancer, where neoadjuvant chemotherapy is the treatment modality of choice. Inclusion criteria: Age >18 years Early (T1-2, N0-1), locally advanced or inflammatory breast cancer Normal left ventricular function, haematological and biochemical parameters ECOG PS 0-1 Exclusion criteria: Metastatic disease Bilateral breast cancer Pregnancy/breastfeeding Inability to give informed consent At diagnosis, patients consented to providing two core needle biopsies in addition to a diagnostic biopsy. Axillary nodal status was determined by axillary ultrasound, fine needle aspiration cytology, and pre-treatment sentinel node biopsy if pre-operative axillary staging was negative. Chemotherapy was administered as per standard institutional practice: 6 cycles fluourouracil, epirubicin and cyclophosphamide (FEC) in node-negative patients; 3 cycles of FEC followed by 3 cycles of docetaxel in node positive patients. Neoadjuvant trastuzumab was given in Her2 positive patients. Imaging (mammography and ultrasound) was repeated after three cycles, and repeat FFPE and snap frozen core biopsies undertaken. At conclusion of treatment, patients underwent surgery as appropriate (mastectomy or breast conservation at the discretion of the operating surgeon), with axillary node clearance for patients who were node positive at diagnosis. Further biopsies (FFPE and fresh frozen) were taken intra-operatively. Plasma samples were obtained at diagnosis, mid-treatment and surgery. Pathological reporting of the surgical specimen was standardised using the residual cancer burden (RCB) reporting system. Aims · To assess the feasibility of carrying out the DDRD assay on diagnostic core biopsy specimens · To evaluate the turn-around time for the assay to assess feasibility of integration into the breast cancer treatment pathway · To assess the correlation of DDRD assay scores and pathological tumour response · Exploratory biomarker analysis will be carried out within Queen's University, Belfast, including: o correlation of DDRD score with changes in Ki67 protein level after three cycles of chemotherapy o exploratory analysis of chemokine expression in peripheral plasma samples, and correlation with pathological response to treatment Accrual The study opened in April 2014. Accrual to date is 14 patients. Citation Format: McIntosh SA, Parkes EE, James CR, Lioe T, Lowry K, Keating KE, Khambata-Ford S, Kennedy RD. Neo-DDRD: A biomarker-driven neoadjuvant feasibility study in breast cancer. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr OT3-02-07.

Preoperative axillary lymph node staging by ultrasound-guided cytology using a four-level sonographic score.

BackgroundThe staging of axillary lymph nodes is critical to the management and prognosis of breast cancer, the most frequent cancer in females. Neoadjuvant therapy and lymph node dissection are recommended when malignant cells invade the lymph nodes. Therefore the pre-operative examination of these lymph nodes is crucial to treatment.MethodsIn this study, we examined the effectiveness of cytology through ultrasound-guided fine needle aspiration (USG-FNA) and ultrasound (US) imaging using an established classification system in correctly identifying lymph node status compared to the final histological results after surgery.ResultsCytology by USG-FNA and US classification were found to be promising methods of axillary lymph node staging.ConclusionsUS and CB offer minimally invasive techniques to pre-operatively examine these lymph nodes in patients with primary breast cancer.

Axillary ultrasound and fine-needle aspiration in preoperative staging of axillary lymph nodes in patients with invasive breast cancer.

ObjectiveTo propose an algorithm to determine the necessity for ultrasonography-guided fine-needle aspiration (US-FNA) in preoperative axillary lymph node staging of patients with invasive breast cancer.Materials and MethodsProspective study developed at National Cancer Institute. The study sample included 100 female patients with breast cancer referred for axillary staging by US-FNA.ResultsThe overall US-FNA sensitivity was set at 79.4%. The positive predictive value was calculated to be 100%, and the negative predictive value, 69.5%. The US-FNA sensitivity for lymph nodes with normal sonographic features was 0%, while for indeterminate lymph nodes it was 80% and, for suspicious lymph nodes, 90.5%. In the assessment of invasive breast tumors stages T1, T2 and T3, the sensitivity was respectively 69.6%, 83.7% and 100%. US-FNA could avoid sentinel node biopsy in 54% of cases.ConclusionAxillary ultrasonography should be included in the preoperative staging of all patients with invasive breast cancer. The addition of US-FNA in cases of lymph nodes suspicious for malignancy may prevent more than 50% of sentinel lymphadenectomies, significantly shortening the time interval to definitive therapy.

Use of sulphur hexafluoride microbubbles injection to identify the sentinel lymph node in breast cancer patients: initial experience in a UK breast unit

In our Trust, all breast cancer patients undergo preoperative axillary staging with ultrasound. Over the past year we have introduced intradermal sulphur hexafluoride microbubbles ultrasound contrast injection to help identify sentinel lymph nodes for a preoperative needle biopsy in each patient. Only patients with malignant node morphology on grey-scale ultrasound undergo biopsy without microbubbles injection.

P034. Preoperative axillary staging – Can core biopsy become the gold standard?

P034. Preoperative axillary staging – Can core biopsy become the gold standard?

P035. Reaching a national consensus on the surgical management of multiple ipsilateral breast cancers (MIBCs): Perceptions by patients, healthy volunteers, surgeons and breast cancer associations

P035. Reaching a national consensus on the surgical management of multiple ipsilateral breast cancers (MIBCs): Perceptions by patients, healthy volunteers, surgeons and breast cancer associations

P071. Axillary lymph node surgery in breast cancer patients: Yield of lymph node metastases at initial axillary surgery and subsequent axillary clearance

Introduction: In our Trust, all breast cancers undergo pre-operative axillary staging with ultrasound and, where appropriate, needle biopsy. This triages patients to sentinel lymph node biopsy (SLNB) or more invasive axillary node clearance (ANC). Where SLNB demonstrates node metastasis, patients may require a second surgical procedure (ANC) or axillary radiotherapy, both associated with additional patient morbidity. We present an audit of our practice, particularly the yield of positive nodes at SLNB, ANC, and subsequent ANC, performed after a positive SLNB.

Abstract P2-01-14: Pre-operative axillary staging results in over-treatment in some breast cancer patients

Abstract Introduction Following a diagnosis of breast cancer, pre-operative ultrasound staging of the axilla is recommended. Patients found to have metastatic disease on biopsy or FNA can proceed directly to axillary clearance (ALNC) at the time of their breast tumour excision. However, although ultrasound staging is a sensitive test to detect axillary disease, it does not differentiate between low and high volume nodal metastasis. Recent evidence suggests that, in selected patients with low volume axillary disease following SLNB, completion ALNC may be safely omitted. This has been reflected in the recently updated ASCO guidelines. In light of this current trend towards axillary conservation, some patients undergoing ALNC after positive axillary staging may be over-treated. The aims of this study is to establish the nodal burden of patients undergoing ALNC following positive axillary staging and to compare the nodal burden of those patients with those undergoing completion ALNC after a positive SLNB. Methods Data was collected prospectively over 12 months from nine hospitals within the North of England Cancer Network. Age, tumour characteristics, breast operation, axillary staging results, axillary operation(s) and nodal results were recorded. Results A total of 1010 patients with breast cancer underwent pre-operative axillary staging. 215 patients (21%) had an ALNC. Of these, 115 (53%) cases underwent a primary ALNC after positive staging. The remaining 100 (47%) patients had a completion ALNC following a positive SLNB. The nodal burden for patients undergoing ALNC is shown in the table below: Total number of positive nodesALNC after positive stagingALNC after positive SLNB n patients% patientsn patients% patients087001322847472131124243121011114111044≥539341414Totals115 100 Analysis of the data revealed that tumour size was a significant predictor of low volume axillary disease (i.e. <3 nodes positive) [p=0.02, Mann-Whitney test]. Conclusion In this study, 46% of patients undergoing ALNC after positive staging had low volume disease (2 or less positive nodes). In the context of recent evidence if these patients had undergone a SLNB following the positive pre-operative staging they may have avoided a completion ALNC. This study demonstrates tumour size to be a significant predictor of low volume axillary disease and thus may be an important factor to consider alongside pre-operative staging when selecting patients who may be better managed by a SLNB rather than proceeding directly to ALNC. Citation Format: Andrew Pieri, Henry Cain, Sebastian Aspinall. Pre-operative axillary staging results in over-treatment in some breast cancer patients [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P2-01-14.

The Z0011 Trial: Is this the end of axillary ultrasound in the pre-operative assessment of breast cancer patients?

The Z0011 trial questioned the role of axillary ultrasound (AxUS) in preoperative staging of breast cancer in patients with ≤2 positive sentinel lymph nodes (SLN). The purpose of this study was to correlate the number of abnormal nodes on AxUS with final nodal burden and determine the utility of AxUS with sampling (AxUS + S) in preoperative staging. Six hundred and seventy-nine patients underwent pre-operative AxUS. Suspicious nodes were sampled. Negative axillae proceeded to SLN biopsy. The number of abnormal nodes identified on ultrasound and final histology as well as sensitivity and specificity for AxUS + S were calculated. Subgroup analysis was performed on Z0011 eligible patients. Two hundred and ninety-six patients had positive axillary nodes on final histology with 169 detected by AxUS + S (sensitivity 86.2%, specificity 100%, PPV 100 %, NPV 71.9%). Patients with nodal metastases identified by AxUS had a mean burden of 7.3 nodes on histology (1 node on AxUS = 5.2 nodes on histology, 2 nodes on AxUS = 7.5 nodes, >2 nodes = 10.1 nodes). Patients diagnosed on SLNB had a mean burden of 2.2 nodes. A single nodal metastasis detected on AxUS + S correlated with a mean of 5.2 nodes on final histology highlighting that AxUS remains essential in guiding appropriate management of the axilla in breast cancer. • Axillary ultrasound +/- sampling is an essential technique in preoperative axillary staging. • Axillary ultrasound findings correlate with final histological axillary node disease burden. • Axillary ultrasound can help triage patients who require axillary lymph node dissection. • The role of axillary ultrasound in breast cancer staging continues to evolve.

209. Pre-operative axillary staging results in overtreatment in some breast cancer patients

209. Pre-operative axillary staging results in overtreatment in some breast cancer patients

Prospect and guideline update of sentinel lymph node biopsy for patients with early-stage breast carcinoma

Axillary lymph nodes are the most common and initial site of metastasis of breast carcinoma. Precise axillary staging of breast carcinoma before initial treatment is crucial as it allows efficient identification for local and systemic treatment options, and provides prognostic information. Sentinel lymph node biopsy (SLNB) is an accurate minimally invasive technology for axillary staging. Although top evidence of high-quality clinical trials showed that SLNB could safely and effectively replace axillary lymph node dissection (ALND) for axillary negative patients with decrease in complications and improvement in quality of life, there are specific indications and contraindications for SLNB. Clinicians should balance the compliance of guideline and native clinical practice, especially for the circumstance of multifocal/multicentric lesion, breast biopsy history, and neoadjuvant chemotherapy. With the accumulation of clinical practice and new results of clinical trials, axillary therapy has changed from unique surgery to patient-tailored multi-disciplinary intervention, although ALND should be recommended traditionally if SLNB is positive. Intensive and accurate preoperative axillary staging is gradually valued by clinicians. Development of imaging modality especially ultrasonography and ultrasound-guided biopsy can identify some extra lymph node positive patients directly to ALND with avoidance of unnecessary SLNB. Thus, the positive rate of SLNB will decline significantly. It seems possible that axillary management will step into a noninvasive era abandoning SLNB in some patients with small breast cancer. In this article we review the prospect and guideline update of SLNB for patients with early-stage breast cancer.

The sensitivity of pre-operative axillary staging in breast cancer: Comparison of invasive lobular and ductal carcinoma

IntroductionAxillary ultrasound (AUS) with fine-needle aspiration (FNA) biopsy of abnormal lymph nodes is important for pre-operative staging and planning the surgical management of the axilla. Invasive lobular carcinoma (ILC) metastases are thought to be difficult to detect because the cells are small and on cytology resemble lymphocytes. To investigate this we directly compared the sensitivity of pre-operative axillary staging between ILC and invasive ductal carcinoma (IDC). MethodConsecutive patients that presented in a single breast unit with pure IDC between April 2005 and December 2006 and pure ILC between January 2008 and December 2012 were retrospectively identified from pathology records. Pre-operative axillary ultrasound and FNA biopsy results were compared with post-operative histopathology from the sentinel node biopsy (SNB) or axillary lymph node dissection (ALND). ResultsA total of 275 and 142 axillae were identified in the IDC and ILC groups respectively. In the node positive patients there was no significant difference in the sensitivity of AUS (IDC vs. ILC; 58.7% vs. 52.8%). However, there was a significant difference in the sensitivity of ultrasound-guided FNA biopsy of abnormal nodes (IDC vs. ILC; 98.4% vs. 53.6%; p < 0.001). ConclusionAUS has comparative sensitivities between IDC and ILC populations. In contrast, FNA biopsy of abnormal axillary nodes is clearly less sensitive in the ILC group. In these patients, who have abnormal AUS, we suggest that a core biopsy is required to improve the pre-operative staging and prevent unnecessary surgical procedures.

PB.49: Preoperative axillary staging in breast cancer patients: repeat sampling in cases of suspicious ultrasound or inconclusive cytology

In our Trust preoperative axillary staging comprises ultrasound with appearances scored LN1 to LN5, and fine needle aspiration (FNA) of LN3 to LN5 nodes. Repeat sampling with FNA or core biopsy (CB) is performed on inconclusive FNA (C1, C3, C4) at the discretion of the radiologist. Repeat sampling is also performed in LN4/5 C2 patients. There has been a trend toward the more invasive and expensive CB for repeat axillary sampling in our unit. Here we assess our practice and the diagnostic yield from repeat sampling, to review current departmental guidelines.

An evaluation of a tool to predict the probability of sentinel lymph node metastasis and its utilization in operative management

Introduction: Intraoperative analysis of Sentinel lymph-nodes (SLN) allows, if indicated, axillary clearance to be done during primary surgery thus avoiding a second procedure. Recent advances in preoperative axillary node staging have reduced the percentage of positive sentinel node biopsies with significant impact on theatre utilization. We evaluated a tool to identify a group of patients in whom routine intra-operative analysis of SLN can be avoided.