Sentinel lymphadenectomy for the staging of clinical axillary node-negative breast cancer before neoadjuvant chemotherapy

Swedish prospective multicenter trial on the accuracy and clinical relevance of sentinel lymph node biopsy before neoadjuvant systemic therapy in breast cancer

Purpose

The timing of sentinel lymph node biopsy (SLNB) in the context of neoadjuvant systemic therapy (NAST) in breast cancer is still controversial. SLNB before NAST has been evaluated in few single-institution studies in which axillary lymph node dissection (ALND), however, was commonly not performed in case of a negative SLNB. We investigated the potential clinical relevance of SLNB before NAST by performing ALND in all patients after NAST.

Methods

This national multicenter trial prospectively enrolled clinically node-negative breast cancer patients planned for NAST at 13 recruiting Swedish hospitals between October 2010 and December 2015. SLNB before NAST was followed by ALND after NAST in all individuals. Repeat SLNB after NAST was encouraged but not mandatory.

Results

SLNB before NAST was performed in 224 patients. The identification rate was 100% (224/224). The proportion of patients with a negative SLNB before NAST but positive axillary lymph nodes after NAST was 7.4% (nine of 121 patients, 95% CI 4.0–13.5). Among those with a positive SLNB before NAST, 23.2% (86/112) had further positive lymph nodes after NAST.

Conclusions

In clinically node-negative patients, SLNB before NAST is highly reliable. With this sequence, ALND and regional radiotherapy can be safely omitted in patients with a negative SLNB provided good clinical response to NAST. Additionally, SLNB-positive patients upfront will receive correct nodal staging unaffected by NAST and be consequently offered adjuvant locoregional treatment according to current guidelines pending the results of ongoing randomized trials.

[Assessment of sentinel lymph node biopsy in patients receiving neoadjuvant chemotherapy in breast cancer: before or after?]

The main goal of preoperative chemotherapy is to reduce the size of the tumor and allow conservative treatment. Neoadjuvant treatment can affect axillary status with a downstaging in one third of the cases. For these patients, the benefit of axillary node dissection is questioned and the sentinel node biopsy (SLNB) seems to be a relevant option. However, the timing of performing SLNB is still debated especially for clinical negative patients with negative axillary ultrasound before preoperative chemotherapy. For axillary positive nodes proved by biopsy/cytology before preoperative chemotherapy, SLNB can be an option if there is a good clinical and radiological response.

Sentinel lymph nodes for breast carcinoma: an update on current practice

Sentinel lymph node (SLN) biopsy has been established as the standard of care for axillary staging in patients with invasive breast carcinoma and clinically negative lymph nodes (cN0). Historically, all patients with a positive SLN underwent axillary lymph node dissection (ALND). The ACOSOG Z0011 trial showed that women with T1-T2 disease and cN0 who undergo breast-conserving surgery and whole-breast radiotherapy can safely avoid ALND. The main goal of SLN examination should be to detect all macrometastases (>2 mm). Gross sectioning of SLNs at 2-mm intervals and microscopic examination of one haematoxylin and eosin-stained section from each SLN block is the preferred method for pathological evaluation of SLNs. The role and timing of SLN biopsy for patients who have received neoadjuvant chemotherapy is controversial, and continues to be explored in clinical trials. SLN biopsies from patients with invasive breast carcinoma who have received neoadjuvant chemotherapy pose particular challenges for pathologists.

Sentinel lymph node biopsy and neoadjuvant chemotherapy in breast cancer patients

ABSTRACT: 

Patient selection and timing of sentinel lymph node (SLN) in the context of primary chemotherapy continues to evolve; there is some evidence that primary chemotherapy may modify lymphatic drainage patterns and cause differential downstaging between SLNs and non-SLNs. SLN biopsy undertaken prior to chemotherapy will minimize the risk of a false-negative result, may allow more accurate initial staging and provides important information on prognostication which can guide decisions about adjuvant radiotherapy. However, quantification of regional metastatic load is incomplete and some advocate SLN biopsy after primary chemotherapy to take advantage of nodal downstaging and avoidance of axillary dissection in up to 40% of patients. Initial reports on false-negative rates for SLN biopsy after primary chemotherapy in patients who had proven axillary node metastases at presentation based on needle core biopsy were relatively high and a cause for clinical concern. However, more recent data suggest that SLN biopsy is as accurate when performed post- as pre-neochemotherapy and current practice incorporates both approaches.

Accuracy and axilla sparing potentials of sentinel lymph node biopsy with methylene blue alone performed before versus after neoadjuvant chemotherapy in breast cancer: a single institution experience

INTRODUCTION

The timing of sentinel lymph node biopsy (SLNB) of breast cancer in the neoadjuvant setting is still controversial. We retrospectively analyzed a Chinese patient cohort with neoadjuvant chemotherapy (NAC) to evaluate the accuracy and axilla sparing potentials of different SLNB timings with methylene blue alone for lymphatic mapping.

MATERIALS AND METHODS

Patients with NAC and axillary lymph node dissection (ALND) and either pre- or post-NAC SLNB were eligible. Clinicopathological characteristics, identification rate (IR), false-negative rate (FNR), accuracy, and positive-predictive value were calculated and compared between the pre- and post-NAC SLNB group using appropriate statistical methods. Axilla sparing potentials of different SLNB timings were evaluated and compared.

RESULTS

One hundred and fifteen eligible cases were included, and 58 had pre-NAC SLNB while the other 57 had post-NAC SLNB. Both groups were comparable in clinicopathological characteristics, neoadjuvant treatments and pathologic complete response rate. IR, FNR, and accuracy of SLNB, as pre-NAC versus post-NAC, were 100 versus 98.2 % (P = 0.496), 0 versus 8.0 % (P = 0.181), and 100 versus 96.4 % (P = 0.239), respectively. Post-NAC SLNB had significantly higher positive-predictive value for ALNs than pre-NAC SLNB (70.0 vs. 36.4 %, P = 0.014), suggesting as high as 63.6 % of ALND performed in the pre-NAC group could have been avoided while only 30 % of ALND in the post-NAC group were theoretically unnecessary.

CONCLUSIONS

Both SLNB timings of breast cancer patients with NAC were feasible and accurate. Although pre-NAC SLNB tends to be better in accuracy, post-NAC SLNB is significantly superior in terms of axilla sparing.

Is optimal timing of sentinel lymph node biopsy before neoadjuvant chemotherapy in patients with breast cancer? A literature review

BACKGROUND

Twenty five percent of women with breast cancer who undergo preoperative chemotherapy do not have axillary metastases. These patients need to withstand sentinel lymph node biopsy (SLNB). The optimal timing of SLNB in patients with neoadjuvant chemotherapy has not yet been defined.

METHODS

We systematically reviewed the literature for studies concerning the efficacy of sentinel lymph node biopsy before neoadjeuvant chemotherapy. A literature search was performed for the years 1993 through 2011 using the databases MEDLINE and EMBASE. Data that assessed the reliability of sentinel lymph node biopsy before chemotherapy were collected.

RESULTS

We identified 10 high-quality studies from 387 papers, which are analyzed further in this review. The identification rates reported ranged from 97% to 100%. The sensitivities of sentinel lymph node biopsy were 100%, and the false negative rates were 0%. Use an isotope combined with blue dye was associated with a higher probability of identification than that of using an isotope or blue dye alone (99.5% vs 98.5%). Only two studies compared data based on different timing for the sentinel lymph node biopsy. They achieved a lower false negative rate (0% vs 15.8%) and higher success rate (100% vs 81%) in patients with sentinel lymph node biopsy prior to neoadjuvant chemotherapy.

CONCLUSION

Sentinel lymph node biopsy prior to chemotherapy potentially gives a more accurate evaluation of axillary status, because it is unaffected by any previous therapeutic intervention.

The sentinel node procedure in breast cancer: nuclear medicine as the starting point

Axillary node status is a major prognostic factor in early breast cancer. Staging with sentinel node biopsy (SNB) leads to a substantial reduction in surgical morbidity. Recent multiinstitutional studies revealed SNB false-negative rates ranging from 5.5% to 16.7%, higher than the target (<5%) set by the 2005 guidelines of the American Society of Clinical Oncology. These alarming data point to the necessity of optimization. Dual mapping with radiotracer and blue dye, combining 2 different injection sites, and routinely using lymphoscintigraphy may improve accuracy. Factors associated with decreased sensitivity, such as prior excisional biopsy or neoadjuvant chemotherapy, should be recognized. The use of SNB in situations with a high prevalence of node positivity (large tumor, multifocality) is controversial. The risk of missed disease after negative SNB ranges from 1% to 4% in patients with T1 tumor and up to 15% in patients with T3. With peritumoral injection, internal mammary drainage is seen in about 20% of cases. Patients combining internal mammary drainage with a positive axillary sentinel node have close to a 50% probability of internal mammary involvement. Lymphoscintigraphy might thus be helpful in selecting patients for whom internal mammary radiation has a high benefit-to-risk ratio.

[Breast surgery after neoadjuvant chemotherapy]

The aim of this work is to specify surgical procedures for the breast and the axillary lymph node area after neoadjuvant chemotherapy. The extent of glandular resection was chosen using a rational based on the goals of neoadjuvant chemotherapy, the prognostical impact of response level and the evaluation of this response. The results of sentinel lymph node procedure before or after neoadjuvant chemotherapy are presented.

Sentinel lymph node biopsy in breast cancer: a comprehensive literature review

Sentinel lymph node biopsy has emerged as the new standard of care for nodal staging in early-stage breast disease. In the this review, the procedure of SLNB in breast cancer will be examined in greater detail with the aim of understanding techniques that may improve results and of identifying future research questions in this field.