Role of axillary clearance after a tumor-positive sentinel node in the administration of adjuvant therapy in early breast cancer

Early-Stage Breast Cancer in the Elderly: Confronting an Old Clinical Problem

Breast cancer generally develops in older women and its incidence is continuing to increase with increasing age of the population. The pathology and biology of breast cancer seem to be different in the elderly, often resulting in the undertreatment of elderly patients and thus in higher rates of recurrence and mortal-ity. The aim of this review is to describe the differences in the biology and treatment of early breast cancer in the elderly as well as the use of geriatric assessment methods that aid decision-making. Provided there are no contraindications, the cornerstone of treatment should be surgery, as the safety and efficacy of surgical resection in elderly women have been well documented. Because most breast cancers in the elderly are hormone responsive, hormonal therapy remains the mainstay of systemic treatment in the adjuvant setting. The role of chemotherapy is limited to patients who test negative for hormone receptors and demonstrate an aggressive tumor profile. Although the prognosis of breast cancer patients has generally improved during the last few decades, there is still a demand for evidence-based optimization of therapeutic interventions in older patients.

A systematic review and economic evaluation of intraoperative tests [RD-100i one-step nucleic acid amplification (OSNA) system and Metasin test] for detecting sentinel lymph node metastases in breast cancer

BACKGROUND

In breast cancer patients, sentinel lymph node biopsy is carried out at the same time as the removal of the primary tumour to postoperatively test with histopathology for regional metastases in the sentinel lymph node. Those patients with positive test results are then operated on 2-4 weeks after primary surgery to remove the lymph nodes from the axilla (axillary lymph node dissection, ALND). New molecular tests RD-100i [one-step nucleic acid amplification (OSNA); based on messenger RNA amplification to identify the cytokeratin-19 (CK19) gene marker] (Sysmex, Norderstedt, Germany) and Metasin (using the CK19 and mammaglobin gene markers) (Cellular Pathology, Princess Alexandra Hospital NHS Trust, Harlow, UK) are intended to provide an intraoperative diagnosis, thereby avoiding the need for postoperative histopathology and, in positive cases, a second operation for ALND.

OBJECTIVE

To evaluate the clinical effectiveness and cost-effectiveness of using OSNA and Metasin in the NHS in England for the intraoperative diagnosis of sentinel lymph nodes metastases, compared with postoperative histopathology, the current standard.

DATA SOURCES

Electronic databases including MEDLINE, MEDLINE In-Process & Other Non-Indexed Citations, EMBASE, The Cochrane Library and the Health Economic Evaluations Database as well as clinical trial registries, grey literature and conference proceedings were searched up to July 2012.

REVIEW METHODS

A systematic review of the evidence was carried out using standard methods. Single-gate studies were used to estimate the accuracy of OSNA with histopathology as the reference standard. The cost-effectiveness analysis adapted an existing simulation model of the long-term costs and health implications of early breast cancer diagnostic outcomes. The model accounted for the costs of an extended first operation with intraoperative testing, the loss of health-related quality of life (disutility) from waiting for postoperative test results, disutility and costs of a second operation, and long-term costs and disutility from lymphoedema related to ALND, adjuvant therapy, locoregional recurrence and metastatic recurrence.

RESULTS

A total of 724 references were identified in the searches, of which 17 studies assessing test accuracy were included in the review, 15 on OSNA and two on Metasin. Both Metasin studies were unpublished. OSNA sensitivity of 84.5% [95% confidence interval (CI) 74.7% to 91.0%] and specificity of 91.8% (95% CI 87.8% to 94.6%) for patient nodal status were estimated in a meta-analysis of five studies [unadjusted for tissue allocation bias (TAB)]. At these values and a 20% node-positive rate, OSNA resulted in lifetime discounted cost-savings of £498 and a quality-adjusted life-year (QALY) loss of 0.048 relative to histopathology, that is, £4324 saved per QALY lost. The most favourable plausible scenario for OSNA in terms of the node-positive rate (range 10-40%), diagnostic accuracy values (91.3% sensitivity and 94.2% specificity, from three reports that adjusted for TAB), the costs of histopathology, OSNA and second surgery, and long-term costs and utilities resulted in a maximum saving per QALY lost of £10,500; OSNA sensitivity and specificity would need to be ≥ 95% for this figure to be ≥ £20,000.

LIMITATIONS

There is limited evidence on the diagnostic test accuracy of intraoperative tests. The quality of information on costs of resource utilisation during the diagnostic pathway is low and no evidence exists on the disutility of waiting for a second surgery. No comparative studies exist that report clinical outcomes of intraoperative diagnostic tests. These knowledge gaps have more influence on the decision than current uncertainty in the performance of postoperative histopathology in standard practice.

CONCLUSIONS

One-step nucleic acid amplification is not cost-effective for the intraoperative diagnosis of sentinel lymph node metastases. OSNA is less accurate than histopathology and the consequent loss of health benefits in this patient group is not compensated for by health gains elsewhere in the health system that may be obtained with the cost-savings made. The evidence on Metasin is insufficient to evaluate its cost-effectiveness.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42012002889.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Relationship between sentinel lymph nodes and postoperative tangential fields in early breast cancer, evaluated using SPECT/CT

Single-photon emission computed tomography/computed tomography (SPECT/CT) demonstrates the precise location of the sentinel lymph nodes (SLNs) in patients with breast cancer. We evaluated the relationship between SLNs and postoperative tangential fields by using SPECT/CT images. Subjects included 72 patients with early breast cancer who underwent SPECT/CT of the SLNs and received whole-breast irradiation with tangential fields after partial mastectomy. The SLN locations evaluated by using SPECT/CT images were entered into the treatment-planning CT image with a 5-mm-diameter sphere. A 15-mm-diameter sphere including the 5-mm treatment margin around the SLNs was defined as PTV-SLN. The PTV-SLN doses with tangential irradiation were evaluated and expressed as the percentage of the prescribed dose. In 69 patients, SLNs were detected by using SPECT/CT; 68 SLNs were located at axillary lymph node Level I, and one was located at Level II. A total of 62 SLNs (90%) were determined to be located inside the tangential fields on the digitally reconstructed radiography (DRR) images. The median doses of SLN center, mean PTV-SLN dose, and PTV-SLN D95 (the minimum dose delivered to 95% of the volume) were 94.1% (range, 15.3-101.9%), 93.7% (range, 29.3-104.0%) and 84.8% (range, 6.8-99.8%). The D95 for the SLNs with treatment margins were ≤90% of the prescribed doses in more than half of the cases. Modification of the individual treatment fields seemed to be necessary to ensure coverage of the SLNs in whole-breast irradiation.

[Prophylactic axillary radiotherapy for breast cancer]

Adjuvant radiotherapy, after breast conserving surgery or mastectomy for breast cancer, improves overall survival while decreasing the risk of recurrence. However, prophylactic postoperative radiotherapy of locoregional lymph nodes for breast cancer, particularly of the axillary region, is still controversial since the benefits and the risks due to axillary irradiation have not been well defined. To begin with, when performing conformal radiotherapy, volume definition is crucial for the analysis of the risk-benefit balance of any radiation treatment. Definition and contouring of the axillary lymph node region is discussed in this work, as per the recommendations of the European Society for Radiotherapy and Oncology (ESTRO). Axillary recurrences are rare, and the recent trend leads toward less aggressive surgery with regard to the axilla. In this literature review we present the data that lead us to avoid adjuvant axillary radiotherapy in pN0, pN0i+ and pN1mi patients even without axillary clearance and to perform it in some other situations. Finally, we propose an update about the potential toxicity of adjuvant axillary irradiation, which is essential for therapeutic decision-making based on current evidence, and to guide us in the evolution of our techniques and indications of axillary radiotherapy.

[Regional treatment for axillary lymph node micrometastases of breast cancer]

In patients with breast cancer, axillary lymph node micrometastasis detection has been more frequent with a better definition since the introduction of the sentinel node procedure. In this review, we focus on pN1mi micrometastasis and review the literature in order to determine factors involved in making the decision of a regional treatment.

The clinical utility of assessment of the axilla in women with suspicious screen detected breast lesions in the post Z0011 era

Axillary ultrasound (AUS) and biopsy are now part of the preoperative assessment of breast cancer based on the assumption that any nodal disease is an indication for axillary clearance (AC). The Z0011 trial erodes this assumption. We applied Z0011 eligibility criteria to patients with screen detected cancers and positive axillary assessment to determine the relevance of AUS to contemporary practice. Women screened between 1/1/2012 and 30/6/2013 and assessed for lesions with highly suspicious imaging features are included. We analysed demographic and assessment data and ascertained the final histopathology with particular reference to axillary nodal status. Among 449 lesions, AUS was recorded in 303 lesions (67.5 %). 290 (96 %) were carcinomas, 30.3 % with nodal disease. AUS was abnormal in 46 (15.9 %). AUS had a sensitivity of 39.8 %, specificity 94.6 %, positive predictive value (PPV) 79.2 % and negative predictive value (NPV) 78.1 %. Axillary FNAB was positive in 27 women, suspicious in two, benign in 16 and not performed in one. In one FNA positive case, the lesion was a nodular breast primary in the axillary tail in a multifocal breast cancer. Combining AUS and FNAB, the sensitivity was 76.5 %, specificity 90.9 %, PPV 96.3 % and NPV 55.6 %. Applying the Z0011 inclusion criteria, 24 of the 27 (88.9 %) women with abnormal AUS and positive FNA were ineligible for Z0011-based management. Of three women eligible for Z0011, one proceeded to AC after SN biopsy, leaving only two women (7.4 %) who might have been considered for SN only management had it not been for the results of the axillary assessment. Among women with negative AUS, nodal metastasis was demonstrated in 21.7 %, 86.8 % of these women having only 1-2 positive nodes. Abnormal AUS and FNA preferentially identify candidates for AC. Negative AUS predicts negative or low nodal burden. Axillary assessment streamlines care.

Prognostic value of the lymph node ratio for lymph-node-positive breast cancer- is it just a denominator problem?

Purpose

To examine the prognostic value of lymph node ratio (LNR) for patients with node-positive breast cancer with varying numbers of minimum nodes removed (>5, > 10 and > 15 total node count).

Methods

This study examined the original histopathological reports of 332 node-positive patients treated in the state of New South Wales (NSW), Australia between 1 April 1995 and 30 September 1995. The LNR was defined as the number of positive lymph nodes (LNs) over the total number of LNs removed. The LNR cutoffs were defined as low-risk, 0.01–0.20; intermediate-risk, 0.21– 0.65; and high-risk, LNR >0.65.

Results

The median follow-up was 10.3 years. In multivariate analysis, LNR was an independent predictor of 10-year breast cancer specific survival when > 5 nodes were removed. However, LNR was not an independent predictor when > 15 nodes were removed. In a multivariate analysis the relative risk of death (RR) decreased from 2.20 to 1.05 for intermediate-risk LNR and from 3.07 to 2.64 for high-risk while P values increased from 0.027 to 0.957 for intermediate-risk LNR and 0.018 to 0.322 for high-risk with the number of nodes removed increasing from > 5 to > 15.

Conclusions

Although LNR is important for patients with low node denominators, for patients with macroscopic nodal metastases in several nodes following an axillary dissection who have more than 15 nodes dissected, the oncologist can be satisfied that prognosis, selection of adjuvant chemotherapy and radiotherapy fields can be based on the numerator of the positive nodes.

Electronic supplementary material

The online version of this article (doi:10.1186/s40064-015-0865-2) contains supplementary material, which is available to authorized users.

The lymph node microenvironment and its role in the progression of metastatic cancer

Lymph nodes are initial sites for cancer metastasis in many solid tumors. However, their role in cancer progression is still not completely understood. Emerging evidence suggests that the lymph node microenvironment provides hospitable soil for the seeding and proliferation of cancer cells. Resident immune and stromal cells in the lymph node express and secrete molecules that may facilitate the survival of cancer cells in this organ. More comprehensive studies are warranted to fully understand the importance of the lymph node in tumor progression. Here, we will review the current knowledge of the role of the lymph node microenvironment in metastatic progression.

Optimal management of breast cancer in the elderly patient: current perspectives

Breast cancer (BC) is the most common female malignancy in the world and almost one third of cases occur after 70 years of age. Optimal management of BC in the elderly is a real challenge and requires a multidisciplinary approach, mainly because the elderly population is heterogeneous. In this review, we describe the various possibilities of treatment for localized or metastatic BC in an aging population. We provide an overview of the comprehensive geriatric assessment, surgery, radiotherapy, and adjuvant therapy for early localized BC and of chemotherapy and targeted therapies for metastatic BC. Finally, we attempt to put into perspective the necessary balance between the expected benefits and risks, especially in the adjuvant setting.

ER-poor and HER2-positive: a potential subtype of breast cancer to avoid axillary dissection in node positive patients after neoadjuvant chemo-trastuzumab therapy

PURPOSE

The study was to estimate the likelihood of axillary downstaging and to identify the factors predicting a pathologically node negative status after neoadjuvant chemotherapy (NAC) with or without trastuzumab in HER2-positive breast cancer.

METHODS

Patients with HER2-positive, stage IIa-IIIc breast cancer were enrolled. Axillary status was evaluated by palpation and fine needle aspiration (FNA) before NAC. All patients received 4-6 cycles of PCrb (paclitaxel 80 mg/m2 and carboplatin AUC = 2 d1, 8, and 15 of a 28-day cycle, or paclitaxel 175 mg/m2 and carboplatin AUC = 6 every-3-week) and were non-randomly administered trastuzumab (2 mg/kg weekly or 6 mg/kg every-3-week) or not. After NAC, each patient underwent standard axillary lymph node dissection and breast-conserving surgery or mastectomy. And some patients received sentinel lymph node biopsy (SLNB) before axillary dissection.

RESULTS

Between November-2007 and June-2013, 255 patients were enrolled. Of them, 157 were confirmed as axillary node positive by FNA (group-A) and 98 as axillary node negative either by FNA or impalpable (group-B). After axillary dissection, the overall pathologically node negative rates (pNNR) were 52.9% in group-A and 69.4% in group-B. The ER-poor/HER2-positive subtype acquired the highest pNNR (79.6% in group-A and 87.9% in group-B, respectively) and the lowest rate of residual with ≥4 nodes involvement (1.9% and 3%, respectively) after PCrb plus trastuzumab. In multivariate analysis, trastuzumab added and ER-poor status were independent factors in predicting a higher pNNR in HER2-positive breast cancer. Forty-six tested patients showed that the ER-poor/HER2-positive subtype acquired a considerable high pNNR and axillary status with SLNB was well macthed with the axillary dissection.

CONCLUSIONS

ER-poor/HER2-positive subtype of breast cancer is a potential candidate for undergoing sentinel lymph node biopsy instead of regional node dissection for accurate axillary evaluation after effective downstaging by neoadjuvant chemo-trastuzumab therapy.

Sentinel Node Biopsy Alone versus Completion Axillary Node Dissection in Node Positive Breast Cancer: Systematic Review and Meta-Analysis

Introduction. There has been recent interest in validity of completion axillary node dissection after a positive sentinel node. This systematic review aims to ascertain if sentinel lymph node dissection alone was noninferior to axillary lymph node dissection for breast cancer patients who have a positive sentinel node. Method. A systematic review of the electronic databases Embase, MEDLINE, and Cochrane Register of Controlled Trials was carried out. Only randomised trials that had patients with positive sentinel node as the study sample were included in the meta-analysis using the reported hazard ratios with a fixed effect model. Results. Three randomised controlled trials and five retrospective studies were identified. The pooled effect for overall survival was HR 0.94, 95% CI [0.79, 1.19], and for disease free survival was HR 0.83, 95% CI [0.60, 1.14]. The reported rates for locoregional recurrence were similar in both groups. The surgical morbidity was found to be significantly more in patients who had underwent axillary dissection. Conclusion. Amongst patients with micrometastasis in the sentinel node, no further axillary dissection is necessary. For patients with macrometastasis in the sentinel node, it is reasonable to consider omitting axillary dissection to avoid the morbidity of the procedure.

Prognostic role of micrometastases in sentinel lymph node in patients with invasive breast cancer

BACKGROUND AND PURPOSE OF THE STUDY

Axillary lymph node status at the time of diagnosis remains one of the most important prognostic factors in women with breast cancer. Sentinel lymph node biopsy (SLNB) proved to be a reliable method for the evaluation of axillary nodal status in early-stage invasive breast cancer. The prognostic value and potential therapeutic consequences of SLN micrometastases remains a matter of great debate.

PATIENTS AND METHODS

From January 1998 to March 2011, 1,976 consecutive patients with non-metastatic invasive breast cancer underwent surgical treatment; 1,080 of them (54.6%) underwent SLNB. We collected data regarding demography, preoperative lymphoscintigraphy, type of surgery, histopathologic and immunohistochemical features and adjuvant treatment.

MAIN FINDINGS

A mean number of 2.1 ± 1.4 (range 1-13) SLN per patient were collected, a total of 2,294 nodes. SLNs were macrometastatic in 16.7% of patients and micrometastatic in 3.3%. Among the patients with positive SLN 93.6% underwent complete ALND. The overall survival (OS) and disease-free survival (DFS) of 72 patients with micrometastases in SLN at 60 months was 100%, similar to patients with negative SLN (98.7%), quite different from the DFS of N1-N3 patients (85.8%). Statistically significant differences in OS and DFS were observed between patients with N1mi and the group with N1-N3 sentinel node (p < 0.001 and p = 0.04) and also between patients with negative SLN and those with macrometastatic SLN (p < 0.001 for both).

CONCLUSION

SLN micrometastases could represents an epiphenomenon of peritumoral lymphovascular invasion which impacts independently on the survival of patients with invasive breast cancer.

Clinical outcomes after sentinel lymph node biopsy in clinically node-negative breast cancer patients

Purpose

To evaluate non-sentinel lymph node (LN) status after sentinel lymph node biopsy (SNB) in patients with breast cancer and to identify the predictive factors for disease failure.

Materials and Methods

From January 2006 to December 2007, axillary lymph node (ALN) dissection after SNB was performed for patients with primary invasive breast cancer who had no clinical evidence of LN metastasis. A total of 320 patients were treated with breast-conserving surgery and radiotherapy.

Results

The median age of patients was 48 years, and the median follow-up time was 72.8 months. Close resection margin (RM) was observed in 13 patients. The median number of dissected SNB was two, and that of total retrieved ALNs was 11. Sentinel node accuracy was 94.7%, and the overall false negative rate (FNR) was 5.3%. Eleven patients experienced treatment failure. Local recurrence, regional LN recurrence, and distant metastasis were identified in 0.9%, 1.9%, and 2.8% of these patients, respectively. Sentinel LN status were not associated with locoregional recurrence (p > 0.05). Close RM was the only significant factor for disease-free survival (DFS) in univariate and multivariate analysis. The 5-year overall survival, DFS, and locoregional DFS were 100%, 96.8%, and 98.1%, respectively.

Conclusion

In this study, SNB was performed with high accuracy and low FNR and high locoregional control was achieved.

[Sentinel node invasion: is it necessary to perform axillary lymph node dissection? Randomized trial SERC]

Contribution of axillary lymph node dissection (ALND) is questioned for positive sentinel node (SN), micro-metastasis and isolated tumor cells but also for macro-metastasis. The aim of this work is to precise why a prospective randomized trial is necessary and the design of this trial. Why? For positive SN, the scientific level evidence appears insufficient for validation of ALND omission as a new standard. Rational is presented with non-sentinel node involved rate and number of NSL involved at complementary ALND, axillary recurrence rate, disease free survival rate and adjuvant treatment decision impact. How? The proposed Sentinelle Envahi et Randomisation du Curage (SERC) trial will randomly assign to observation only or complementary ALND with positive SN. The aim is to demonstrate the non-inferiority of ALND omission versus ALND.

[Impact of omission of axillary dissection on adjuvant therapy in patients with metastatic sentinel lymph nodes according to the ACOSOG Z0011 criteria]

OBJECTIVES

The results of the ACOSOG Z0011 questioned the usefulness of axillary lymph node dissection (ALND) in case of metastatic sentinel lymph node (SLN). The aim of our study was to assess the impact of the omission of ALND according to the inclusion criteria of the ACOSOG Z0011 study if SLN are metastatic but also the consequences on prescription of the application of a new standard of care for adjuvant treatment.

PATIENTS AND METHODS

This retrospective study included, between November 2007 and January 2012, patients with T1-T2N0 breast cancer and metastatic SLN meeting the criteria for omission of completion ALND according to the study of the ACOSOG Z0011. Patients were submitted anonymously and randomly in multidisciplinary meeting (MM) 3 times: with complete information including ALND (MM1), with information from SLN alone (MM2) and with complete information of ALND according to the current protocols in 2013 (MM3). During each presentation, we collected the decision of the different adjuvant treatments proposed: chemotherapy, hormonal therapy, radiotherapy (with radiation fields). Then, we compared therapeutic proposals of the 3 presentations.

RESULTS

Fifty-eight patients were eligible for inclusion criteria of the ACOSOG Z0011. Treatments actually proposed during MM1 consisted of 94.8 % of chemotherapy, 77.6 % of breast and lymph nodes radiotherapy and 91.4 % of hormone therapy. During the MM2, there was no significant difference compared to the decision taken during MM1. In fact, during MM2, we decided chemotherapy, radiotherapy and hormonotherapy respectively in 89.7, 79.3 and 91.4 % of the cases. During the MM3, it was shown a significant decrease in the indications of chemotherapy (82.8 %, P=0.03) and lymph nodes irradiation (56.9 %, P=0.02) compared to the therapeutic proposals of the MM1.

DISCUSSION AND CONCLUSION

The lack of information of ALND does not seem to significantly alter indications for adjuvant treatment. Otherwise, the evolution of our references causes a decrease in adjuvant therapy.

The need for axillary lymph node dissection in T1/T2 breast cancer surgery--counterpoint

For breast cancer patients, the role of the axillary lymph node dissection (ALND) in the management of clinically node negative breast cancer patient has shifted from routine, to selective, to increasingly rare. With the publication of the American College of Surgeons Oncology Group (ACOSOG) Z0011 trial results, some are ready to announce the time of death of this procedure. However, many questions remain regarding the design and statistical interpretation of the study, the treatments the patients actually received, and its applicability in clinical practice in light of other studies concerning regional management. Thus, the reports of the ALND's death may be greatly exaggerated. Careful acknowledgement of the study's strengths and shortcomings, and more recent trial data, suggest that although ALND may be safely avoided in a subset of sentinel lymph node positive, Z0011-eligible patients, others may require multidisciplinary review and consensus, and a careful conversation with the patient, before deciding it is not necessary.

Axillary ultrasonography in breast cancer patients helps in identifying patients preoperatively with limited disease of the axilla

BACKGROUND

The sentinel lymph node biopsy (SLNB) procedure is the method of choice for the identification and monitoring of regional lymph node metastases in patients with breast cancer. In the case of a positive sentinel lymph node (SLN), additional lymph node dissection is still warranted for regional control, although 40-65 % have no additional axillary disease. Recent studies show that after breast-conserving surgery, SLNB, and adjuvant systemic therapy, there is no significant difference between recurrence-free period and overall survival if there are ≤2 positive axillary nodes. The purpose of this study was preoperative identification of patients with limited axillary disease (≤2 macrometastases) by using ultrasonography.

METHODS

Data from 1,103 consecutive primary breast cancer patients with tumors smaller than 50 mm, no palpable adenopathy, and a maximum of 2 SLNs with macrometastases were collected. The variable of interest was US of the axilla.

RESULTS

Of the 1,103 patients included, 1,060 remained after exclusion criteria. Of these, 102 (9.6 %) had more than 2 positive axillary nodes on ALND. Selected by unsuspected US, the chance of having >2 positive lymph nodes (LNs) is substantially lower (4.2 %). This is significant on univariate and multivariate analysis. After excluding the patients with extracapsular extension of the SLN, the chance of having >2 positive LNs is only 2.6 %. For pT1-2, this is 2.2 %.

CONCLUSIONS

The risk of more than 2 positive axillary nodes is relatively small in patients with cT1-2 breast cancer. US of the axilla helps in further identifying patients with a minimal risk of additional axillary disease, putting ALND up for discussion.

The integration of locoregional with systemic adjuvant therapy for early-stage breast cancer: the shifting sands of decision-making

SUMMARY Given the generally excellent outcomes for modern breast cancer treatment, the recognition that overtreatment is commonplace is the driving force to reduce the treatment impact of surgery, radiation therapy and chemotherapy. Many recent trials have demonstrated that fewer axillary lymph node dissections, smaller radiation field sizes and less administration of chemotherapy are all feasible without compromising the long-term outcomes. However, each of these trials has studied a single modality while maintaining the intensities of the other modalities. There is a natural tendency, albeit controversial, to reduce more than one modality at a time. We review the literature, and counsel the breast cancer oncologist to work as a multimodality team to decide with the patient which modality can be reduced, and which should be preserved in its intensity.

Sentinel node biopsy in breast cancer revisited

The axilla has long been a focus of clinicians' attention in the management of breast cancer. The approach to the axilla has undergone dramatic changes over the last century, from radical and extended radical excisions, through the introduction of sentinel node biopsy for node negative patients to the current situation where selective management of those with nodal involvement is being introduced. The introduction of lymphatic mapping and sentinel node biopsy in the 1990's has been key to the major changes that have occurred. In less than 20 years it has moved from a hypothesis to a situation where it is the default approach to almost all clinically node negative patients and is being considered in other situations where axillary clearance was previously considered standard. This article reviews the development and introduction of sentinel node biopsy, its current uncertainties and limitations, and possible future developments.

A review of clinical aspects of breast cancer

Breast cancer is the most frequently diagnosed cancer in women and ranks second among causes for cancer related death in women. The ability to identify and diagnose breast cancer has improved markedly. Treatment decisions which were based in the past predominantly on the anatomic extent of the disease are shifting to the underlying biological mechanisms. Gene array technology has led to the recognition that breast cancer is a heterogeneous disease composed of different biological subtypes, and genetic profiling enables response to chemotherapy to be predicted. Breast conservation became an established standard of care and the oncoplastic approach enables wide excisions without compromising the natural shape of the breast. Sentinel lymph node biopsy has replaced axillary dissection as the standard procedure to stage the axilla and spared many patients the excess morbidity of axillary dissection. Targeted therapy to the oestrogen receptor plays a major role in systemic therapy; pathways responsible for endocrine resistance have been targeted as well. Biological therapy has been developed to target HER2 receptor and combination of antibody drug conjugates linked cytotoxic therapy to HER2 antibodies. Meaningful improvements in survival resulted from the new effective systemic agents and patients with metastasis are likely to have a longer survival.

The impact of the pathological lymph node status on adjuvant systemic treatment recommendations in clinically node negative breast cancer patients

Several independent randomized controlled trials are initiated to investigate whether sentinel lymph node biopsy can be safely omitted in clinically node negative breast cancer patients with negative axillary ultrasound findings, who are treated with breast conserving therapy. A consequence of omitting sentinel lymph node biopsy is absence of pathological lymph node status information. We aimed to investigate the impact of omitting sentinel lymph node biopsy on adjuvant systemic treatment recommendations. Data from all consecutive patients with invasive breast cancer and negative axillary ultrasound findings treated with breast conserving therapy and sentinel lymph node biopsy between 2008 and 2012 were collected from a prospective database. Two methods, Adjuvant! Online and the Dutch breast cancer guideline 2012, were used to determine the adjuvant systemic treatment recommendations of every patient. At first, each patient was considered to be lymph node negative, and secondly the patients' true pathological lymph node status was used. A total of 303 patients were consecutively included. Pathological lymph node status was pN0 in 72.3 %, pN0(i+) in 12.9 %, pN1mi+ in 5.6 %, pN1 in 7.3 %, and pN2 in 2.0 % of the patients. The decision to recommend adjuvant systemic treatment changed due to the pathological lymph node status in 1.0 % of the patients (3/303) when using Adjuvant! Online and in 3.6 % (11/303) when using the 2012 Dutch breast cancer guideline. The impact of the pathological lymph node status on adjuvant systemic treatment recommendations in clinically node negative breast cancer patients with negative axillary ultrasound findings treated with breast conserving therapy is limited. The safety of omitting the sentinel lymph node biopsy should be confirmed by the initiated randomized controlled trials.

The real-time intra-operative evaluation of sentinel lymph nodes in breast cancer patients using One Step Nucleic Acid Amplification (OSNA) and implications for clinical decision-making

INTRODUCTION

One Step Nucleic Acid Amplification (OSNA) method for the intraoperative analysis of sentinel lymph nodes (SLNs) in breast cancer, obviates a second operation to the axilla and thereby expedites progression to adjuvant therapy. Recent NICE guidelines have approved OSNA as a method of sentinel node diagnosis to support the above case.(1) METHOD: This is a single centre prospective cohort analysis of all patients undergoing breast cancer surgery including sentinel node biopsy from February 2010 to June 2012. Patients with negative SLN(s) on OSNA had no further axillary surgery. A validation phase was performed prior to using OSNA routinely. Those with micrometastases underwent a level 1 clearance, and >one SLN with macrometastases, underwent treatment by level 2 axillary dissection. The length of time from sentinel node retrieval to OSNA result was recorded.

RESULTS

Four hundred and forty nodes were analysed in 212 patients with a mean age of 55 years (range 24-98). The sensitivity and specificity of OSNA was 93% and 94% respectively in cases of macrometastases. The process required additional median anaesthesia time of 20 min (range -48 to +65 min). Non-sentinel node positivity was 5% and 48% for micrometastasis and macrometastasis respectively.

CONCLUSION

OSNA identified 62 of 212 patients with at least one positive sentinel node, thereby sparing 29% from a second procedure to clear the axilla subsequently. The median waiting time of 20 min for node results from completion of breast procedure is acceptable and allows for an efficient operating list. OSNA can be incorporated into routine practice and with improved methods of imaging preoperatively, can be an excellent adjunct to the breast cancer patient pathway of care.

[Breast cancer and axillary area: state of the art and perspectives]

A therapeutic surgical de-escalation has been observed since many years with an actual prolongation for axillary lymph node area treatment. Axillary lymph node dissection (ALND) omission has been studied before and after validation of sentinel node (SN) biopsy procedure. A non-inferiority of ALND omission has been reported in case of non-involved SN. ALND omission has been studied in case of SN involvement without consensus in relation with scientific level of proof and with selective indications. The purpose of this work is to make a synthesis of the experiences on this subject then to envisage the current and future perspectives.

Optimal treatment of the axilla after positive sentinel lymph node biopsy in early invasive breast cancer. Early results of the OTOASOR trial

Introduction: Sentinel lymph node biopsy alone has become an acceptable alternative to elective axillary lymph node dissection in patients with clinically node-negative early-stage breast cancer. Approximately 70 percent of the patients undergoing breast surgery develop side effects caused by the axillary lymph node dissection (axillary pain, shoulder stiffness, lymphedema and paresthesias). Aim: The current standard treatment is to perform completion axillary lymph node dissection in patients with positive sentinel lymph node biopsy. However, randomized clinical trials of axillary dissection versus axillary irradiation failed to show survival differences between the two types of axillary treatment. The National Institute of Oncology, Budapest conducted a single centre randomized clinical study. The OTOASOR (Optimal Treatment of the Axilla – Surgery or Radiotherapy) trial compares completion axillary lymph node dissection to axillary nodal irradiation in patients with sentinel lymph node-positive primary invasive breast cancer. Method: Patients with primary invasive breast cancer (clinically lymph node negative and less than or equal to 3 cm in size) were randomized before surgery for completion axillary lymph node dissection (arm A–standard treatment) or axillary nodal irradiation (arm B–investigational treatment). Sentinel lymph node biopsy was performed by the radio-guided method. The use of blue-dye was optional. Sentinel lymph nodes were investigated with serial sectioning at 0.5 mm levels by haematoxylin and eosin staining. In the investigational treatment arm patients received 50Gy axillary nodal irradiation instead of completion axillary lymph node dissection. Adjuvant treatment was recommended and patients were followed up according to the actual institutional guidelines. Results: Between August 2002 and June 2009, 2106 patients were randomized for completion axillary lymph node dissection (1054 patients) or axillary nodal irradiation (1052 patients). The two arms were well balanced according to the majority of main prognostic factors. Sentinel lymph node was identified in 2073 patients (98.4%) and was positive in 526 patients (25.4%). Fifty-two sentinel lymph node-positive patients were excluded from the study (protocol violation, patient’s preference). Out of the remaining 474 patients, 244 underwent completion axillary lymph node dissection and 230 received axillary nodal irradiation according to randomization. The mean length of follow-up to the first event and the mean total length of follow-up were 41.9 and 43.3 months, respectively, and there were no significant differences between the two arms. There was no significant difference in axillary recurrence between the two arms (0.82% in arm A and 1.3% in arm B). There was also no significant difference in terms of overall survival between the arms at the early stage follow-up. Conclusions: The authors conclude that after a mean follow-up of more than 40 months axillary nodal irradiation may control the disease in the axilla as effectively as completion axillary lymph node dissection and there was also no difference in terms of overall survival. Orv. Hetil., 154(49), 1934–1942.

Risk stratification of patients with early breast cancer

BACKGROUND

Sentinel lymph node biopsy (SLNB) is the standard procedure performed to stage the axillae, and axillary node clearance (ANC) or radiotherapy is the treatment for nodal involvement. The aims of this study were to assess (1) the role of preoperative axillary ultrasonography (US), (2) the number of positive lymph nodes on ANC after either positive SLNB results or preoperative ultrasonographically guided nodal biopsy, and (3) the role of ANC in patients with node-positive breast cancer.

PATIENTS AND METHODS

All patients with invasive breast cancer and axillary node involvement (but clinically negative nodes on presentation) who underwent ANC between January 2008 and December 2009 were identified, and information regarding clinicopathologic parameters and the nodal yield was collected. ANC was performed for 3 groups: patients with micrometastasis seen in SLNB specimens, macrometastasis seen in SLNB specimens, and positive axillary nodes detected on US biopsy.

RESULTS

ANC was performed 141 times over the 2-year period. Forty-two percent of axillary node involvement was diagnosed by biopsy or preoperative US, and 40% of these patients received neoadjuvant chemotherapy. The remainder of cases were diagnosed by SLNB: 30% had micrometastases and 70% had macrometastases. Fifty percent of cancers with an ultrasonographic diagnosis of lymph node involvement were high grade and 56% had 4 or more positive nodes on ANC; this was significantly higher than in patients with positive SLNB results (P = .0001). Only 20% of patients with macrometastases on SLNB had 4 or more positive nodes in comparison with 56% with positive axillary lymph nodes by US (P < .0001).

CONCLUSION

The routine use of preoperative axillary US and biopsy of abnormal nodes helps in identifying high-risk patients and thus aids in planning treatment.

Management of axillary staging in breast cancer patients treated with neoadjuvant chemotherapy

SUMMARY Sentinel lymph node (SLN) biopsy is standard care for patients with cN0 breast cancer, and SLN-negative patients do not require axillary dissection (ALND). It is now clear that many patients with positive SLN do not require ALND. In ACOSOG Z0011, 6-year locoregional control and survival (in cT1–2N0 patients with ≤2 positive SLN treated by breast conservation and whole breast radiotherapy) were comparable for SLN biopsy alone compared to SLN biopsy plus ALND. A growing body of data now suggests that ALND may not be required for selected patients outside the Z0011 eligibility criteria, including those treated with neoadjuvant chemotherapy (NAC). Retrospective and prospective studies confirm that the success of SLN biopsy after NAC is slightly lower and the false-negative rate slightly higher than those of SLN biopsy in general. The performance of SLN biopsy after NAC is optimized by the use of combined dye–isotope mapping and by the removal of at least two SLN. After NAC, ALND remains standard care for those who remain SLN-positive but may not be required for SLN-negative patients. Future trials will focus on patients with proven axillary node metastasis prior to NAC, and ask whether axillary radiotherapy is required for those who become SLN negative, and whether ALND is required for those who remain SLN-positive.

Which breast cancer decisions remain non-compliant with guidelines despite the use of computerised decision support?

BACKGROUND

Despite multidisciplinary tumour boards (MTBs), non-compliance with clinical practice guidelines is still observed for breast cancer patients. Computerised clinical decision support systems (CDSSs) may improve the implementation of guidelines, but cases of non-compliance persist.

METHODS

OncoDoc2, a guideline-based decision support system, has been routinely used to remind MTB physicians of patient-specific recommended care plans. Non-compliant MTB decisions were analysed using a multivariate adjusted logistic regression model.

RESULTS

Between 2007 and 2009, 1624 decisions for invasive breast cancers with a global non-compliance rate of 8.3% were analysed. Patient factors associated with non-compliance were age>80 years (odds ratio (OR): 7.7; 95% confidence interval (CI): 3.7-15.7) in pre-surgical decisions; microinvasive tumour (OR: 5.2; 95% CI: 1.5-17.5), surgical discovery of microinvasion in addition to a unique invasive tumour (OR: 4.2; 95% CI: 1.4-12.5), and prior neoadjuvant treatment (OR: 4.2; 95% CI: 1.1-15.1) in decisions with recommendation of re-excision; age<35 years (OR: 4.7; 95% CI: 1.9-11.4), positive hormonal receptors with human epidermal growth factor receptor 2 overexpression (OR: 15.7; 95% CI: 3.1-78.7), and the absence of prior axillary surgery (OR: 17.2; 95% CI: 5.1-58.1) in adjuvant decisions.

CONCLUSION

Residual non-compliance despite the use of OncoDoc2 illustrates the need to question the clinical profiles where evidence is missing. These findings challenge the weaknesses of guideline content rather than the use of CDSSs.

The feasibility of a randomised controlled trial for the axillary management of a select group of invasive breast cancer patients: SLNB vs. no-SLNB

BACKGROUND

The results of ZOO11 have shaken our thinking and approach for the axillary management of small invasive breast cancers where the incidence and burden of axillary metastasis would be much less than that of ZOO11 population. The traditional approach of sentinel lymph node biopsy (SLNB) for "all invasive cancers" is challenged because of the diminishing role of axillary lymph nodes (ALNs) status in guiding the adjuvant systemic therapy. Certainly this raises the question of whether SLNB can be avoided in a select group of patients without compromising clinical outcomes. The aim of this study was to identify such a group of patients in whom SLNB is no longer required.

METHOD

Patients with breast cancers ≤2 cm in size and clinically negative axilla who underwent breast conserving surgery (BCS) and SLNB were identified. Patients were divided into different groups; incidence of ALNs metastasis, further non-SLNs metastasis and a total number of tumour positive ALNs of ≥4 were determined.

RESULTS

A total of 194 patients met the criteria; incidence of tumour positive SLNs, further non-SLNs metastasis and a total number of tumour positive ALNs of ≥4 varied between different groups and was 9.3-15.5 %, 0-35 % and 0-2.6 %, respectively. Patients with T1b, grade 1-2 tumours had less than 5 % risk of ALNs macrometastasis.

CONCLUSION

It is possible to identify a group of patients whose burden of axillary disease is acceptably low enough that SLNB can be avoided. Feasibility of a non-inferiority randomised controlled trial (RCT) in a select group of patients with or without SLNB has been explored to compare the distant disease free, disease free and overall survival and axillary relapse rate (ARR).

Does the result of completion axillary lymph node dissection influence the recommendation for adjuvant treatment in sentinel lymph node-positive patients?

OBJECTIVE

The Hungarian National Institute of Oncology has just closed a single-center randomized clinical study. The Optimal Treatment of the Axilla-Surgery or Radiotherapy (OTOASOR) trial compares completion axillary lymph node dissection (cALND) with regional nodal irradiation (RNI) in patients with sentinel lymph node-positive (SLN+) primary invasive breast cancer. In the investigational treatment arm, patients received 50 Gy RNI instead of cALND. In these patients we had information only about the sentinel lymph node (SLN) status, but the further axillary nodal involvement remained unknown. The aim of this study was to investigate whether the result of cALND influenced the recommendation for adjuvant treatment in patients with SLN+ breast cancer.

PATIENTS AND METHODS

Patients with SLN+ primary breast cancer were randomized for cALND (arm A, standard treatment) or RNI (arm B, investigational treatment). Adjuvant systemic treatments were given according to the standard institutional protocol, and patients were followed according to the actual institutional guidelines.

RESULTS

Between August 2002 and June 2009, 474 SLN+ patients were randomized to cALND (arm A, standard treatment = 244 patients) or RNI (arm B, investigational treatment = 230 patients). The 2 arms were well balanced according to the majority of main prognostic factors. However, more patients were premenopausal (34% vs. 27%; P = .095) and had pT2-3 tumors (57% vs. 40%; P = .003) in the completion axillary lymph node dissection (ALND) arm. On the other hand, there were more patients with known human epidermal growth factor receptor type 2 positive tumor (12% vs. 17%, P = .066) in the RNI arm. In the ALND and RNI arms, 78% (190/244) and 69% (159/230), respectively, received chemotherapy (P = .020). Endocrine therapy was administered in 87% (213/244) of the patients in the ALND arm and 89% (204/230) of the patients in the RNI arm (P = .372). Six patients (2.5%) on arm A and 13 patients (5.7%) on arm B received adjuvant trastuzumab treatment (P = not significant). Subgroup analyses explored that more frequent administration of adjuvant chemotherapy in arm A was associated with the higher percentage of premenopausal patients and patients with larger (pT2-3) tumors.

CONCLUSIONS

The result of cALND after positive SLN biopsy seems to have no major impact on the administration of adjuvant systemic therapy.

Evolution of axillary nodal staging in breast cancer: clinical implications of the ACOSOG Z0011 trial

BACKGROUND

Management of the axilla in breast cancer patients has evolved from routine axillary lymph node dissection (ALND) for all patients to a highly selective approach based on the assessment of the sentinel lymph nodes (SLNs) as well as tumor and patient characteristics. Although ALND continues to have an important role in staging and regional control for many breast cancer patients, recent trial results question the need for routine ALND in patients who have positive SLNs.

METHODS

Not all axillary disease becomes clinically detectable or relevant with respect to recurrence and survival. Therefore, recent trends indicate that many surgeons have omitted ALND in subgroups of patients, particularly those with clinically node-negative, SLN-positive, early-stage breast cancer undergoing breast-conserving therapy with postoperative irradiation. This review explores trends in axillary management, focusing primarily on the clinical implications of the results from the American College of Surgeons Oncology Group (ACOSOG) Z0011 randomized controlled trial.

RESULTS

According to the results of the ACOSOG Z0011 trial, the use of SLN dissection alone did not result in inferior survival compared with ALND in patients with limited SLN disease treated with breast-conserving therapy. This subgroup of women was spared the morbidity associated with ALND. However, several points of debate, including the smaller than anticipated sample size, the older study population, and the length of follow-up, suggest caution when applying these findings to all women with breast cancer.

CONCLUSIONS

Although the findings of ACOSOG Z0011 are impressive, in clinical practice they are applicable to a limited number of women with breast cancer: those with T1-2 primary tumors with clinically negative axilla and 1 to 2 positive SLNs undergoing breast-conserving surgery and adjuvant whole-breast irradiation. The next generation of clinical trials may answer some of the remaining questions regarding how best to manage the axilla in additional subsets of patients undergoing treatment of breast cancer.

Ask the Experts: Accelerated partial breast irradiation: the future of radiation therapy for breast cancer?

Bruce G Haffty is currently Professor and Chairman of the Department of Radiation Oncology of the University of Medicine and Dentistry, New Jersey-Robert Wood Johnson Medical School and New Jersey Medical School, and Associate Director of the Cancer Institute of New Jersey (NJ, USA). His medical school and residency training were at Yale University School of Medicine (CT, USA), and he spent the majority of his academic career at Yale School of Medicine, Department of Therapeutic Radiology. He moved to the Robert Wood Johnson Medical School and Cancer Institute of New Jersey in 2005. Haffty is internationally recognized as an expert in breast radiation oncology and has published over 300 peer-reviewed articles, 30 book chapters and numerous editorials and letters. Much of his recent research has been supported by the Breast Cancer Research Foundation. He is consistently listed as one of the country’s leading physicians by Best Doctors in America, Ladies Home Journal, Good Housekeeping, America’s Top Doctors, Top Doctors for Cancer and Top Doctors in New York and New Jersey. In addition to a busy clinical practice, Haffty has served on numerous national committees related to research and education in breast cancer and radiation oncology. He is a past president of the American Radium Society and is the immediate past president of the American Board of Radiology. He is currently Associate Editor of the Journal of Clinical Oncology and President-Elect of the American Society of Radiation Oncology.

Preoperative axillary ultrasound in breast cancer: safely avoiding frozen section of sentinel lymph nodes in breast-conserving surgery

BACKGROUND

The American College of Surgeons Oncology Group Z0011 trial results provided convincing evidence that completion axillary lymph node dissection (CALND) was unnecessary in selected patients with 1 to 2 positive sentinel lymph nodes (SLNs). We hypothesized that preoperative axillary ultrasound (AUS) with fine-needle aspiration is sufficiently sensitive to detect worrisome macrometastasis to preclude the need for frozen-section pathology of SLNs.

STUDY DESIGN

We conducted a retrospective single-institution study at a tertiary academic referral center. A total of 1,140 T1 to 2 breast cancer patients who underwent SLN biopsy with or without CALND from January 1, 2007 to December 31, 2010 were reviewed. All patients had negative preoperative AUS with or without fine-needle aspiration.

RESULTS

One hundred forty-four (13%) patients were node positive at surgery. Mean age, tumor size, histology, and estrogen receptor and progesterone receptor status were similar comparing 996 SLN-negative with 144 (13%) SLN-positive patients. Of the SLN-positive patients, 25% were premenopausal, 9% were estrogen receptor-negative, and 19% had additional lymph nodes at CALND. Only 19 (2%) patients had SLN metastasis ≥6 mm, 10 (1%) had metastasis >7 mm, and only 1 patient had ≥3 positive SLNs.

CONCLUSIONS

The addition of preoperative AUS with or without fine-needle aspiration to management of patients who meet American College of Surgeons Oncology Group Z0011 trial eligibility criteria reduced the risk of macrometastasis measuring ≥6 mm to only 2%; very few of these patients would be premenopausal, have estrogen receptor-negative tumors, or ≥3 positive SLNs. With the addition of AUS with or without fine-needle aspiration, we endorse the conclusions of the American College of Surgeons Oncology Group Z0011 trial to avoid CALND, and see marginal gain in frozen-section analysis of SLNs.

The clinical relevance of axillary reverse mapping (ARM): study protocol for a randomized controlled trial

Background

Axillary lymph node dissection (ALND) in patients with breast cancer has the potential to induce side-effects, including upper-limb lymphedema. Axillary reverse mapping (ARM) is a technique that enables discrimination of the lymphatic drainage of the breast from that of the upper limb in the axillary lymph node (LN) basin. If lymphedema is caused by removing these lymphatics and nodes in the upper limb, the possibility of identifying these lymphatics would enable surgeons to preserve them. The aim of this study is to determine the clinical relevance of selective axillary LN and lymphatic preservation by means of ARM. To minimize the risk of overlooking tumor-positive ARM nodes and the associated risk of undertreatment, we will only include patients with a tumor-positive sentinel lymph node (SLN). Patients who are candidates for ALND because of a proven positive axillary LN at clinical examination can be included in a registration study.

Methods/design

The study will enroll 280 patients diagnosed with SLN biopsy-proven metastasis of invasive breast cancer with an indication for a completion ALND. Patients will be randomized to undergo standard ALND or an ALND in which the ARM nodes and their corresponding lymphatics will be left in situ. Primary outcome is the presence of axillary surgery-related lymphedema at 6, 12, and 24 months post-operatively, measured by the water-displacement method. Secondary outcome measures include pain, paresthesia, numbness, and loss of shoulder mobility, quality of life, and axillary recurrence risk.

Discussion

The benefit of ALND in patients with a positive SLN is a subject of debate. For many patients, an ALND will remain the treatment of choice. This multicenter randomized trial will provide evidence of whether or not axillary LN preservation by means of ARM decreases the side-effects of an ALND. Enrolment of patients will start in April 2013 in five breast-cancer centers in the Netherlands, and is expected to conclude by April 2016.

Trial registration

TC3698

[Micrometastasis: biological entity and clinical impact?]

Micrometastases or sub-micrometastases can be detected by standard histopathological method sometimes associated with immunohistochemistry in lymph nodes, bone marrow and blood. The consequence of these small size involvement may be prognostic and therapeutic. Two factors are necessary to assess this kind of involvement: the rate of involvement of non-sentinel lymph node after axillary lymph node dissection and significative difference of survivals. The rate of involvement of non-sentinel lymph node in case of micrometastases or sub-micrometastases is different from the rate of involvement in case of no lymph node metastases (7 to 8%) or in case of macrometases (30 to 50%). Micrometastase is an important factor to determine the rate of involvement of non-sentinel lymph node, the overall or disease free survival and to assess the need of radiotherapy and chemotherapy. In conclusion, micrometastases and sub-micrometastases have a clinical impact even if complementary axillary lymph node dissection is still discussed.

Landmark trials affecting the surgical management of invasive breast cancer

Significant progress has been made in the surgical management of breast cancer. Most women diagnosed with early stage invasive breast cancer can now be managed with breast-conserving therapy to include a segmental mastectomy followed by radiation. Axillary lymph nodes are routinely assessed by sentinel lymph node biopsy. Axillary lymph node dissection is reserved for patients with documented nodal metastasis; however, here too progress has been made because a population of low-risk patients has been identified in whom a complete dissection is not required even in the setting of a positive sentinel lymph node. This article details the landmark clinical trials that have guided the surgical management of breast cancer.