Sentinel node mapping performed before preoperative chemotherapy may avoid axillary dissection in breast cancer patients with negative or micrometastatic sentinel nodes

Surgical Axillary Staging Before Neoadjuvant Chemotherapy: Who Gets It and Why We Should Avoid It

BACKGROUND

Surgical axillary staging demonstrating positive nodal disease before neoadjuvant chemotherapy (NAC) necessitates axillary lymph node dissection (ALND) post-NAC. Despite evidence supporting post-NAC surgical staging, we hypothesized that there is persistent use of pre-NAC staging and that it is associated with aggressive clinicopathologic features and a higher rate of subsequent ALND.

PATIENTS AND METHODS

Stage I-III breast cancer patients who underwent lymph node staging surgery and received NAC between 2013 and 2017 in the National Cancer Database were included. Sequence of staging surgery and chemotherapy administration was determined. Multivariable regression was used to assess characteristics associated with pre-NAC staging. Rate of ALND was compared between those who had pre- and post-NAC surgical axillary staging.

RESULTS

In total, 120,538 met inclusion; 68% received NAC first and 32% had pre-NAC staging. Pre-NAC staging surgery was associated with younger age (age < 30 versus 40-49 years, HR 1.1) and decreased with older age (ages 70-79/80+ versus 40-49 years, HR 0.86 and 0.73). Advancing clinical T stage, lobular subtype, higher grade, and HR+/HER2- subtype were also associated with pre-NAC surgical staging. Women who underwent pre-NAC surgical staging were more likely to undergo ALND.

CONCLUSIONS

Over 30% of women underwent surgical axillary staging prior to NAC, resulting in higher rates of ALND in this cohort. While certain features suggestive of aggressive behavior (grade and T stage) were associated with pre-NAC surgical axillary staging, women with more aggressive tumor subtypes (triple negative/HER2+) were less likely to undergo pre-NAC surgical axillary staging. Pre-NAC surgical axillary staging should be performed only in rare circumstances to avoid unnecessary ALND.

Management of the Axilla after Neoadjuvant Systemic Therapy

OPINION STATEMENT

As the use of neoadjuvant systemic therapy (NAST) increases, the optimal management of the axilla has become increasingly complex. Consensus among professional organizations is that those patients with clinically negative axillary nodes who are being considered for NAST should undergo a sentinel lymph node (SLN) biopsy following NAST. If a positive SLN is subsequently identified, an axillary lymph node dissection (ALND) is the current standard of care. For patients with clinically node-positive disease, SLN biopsy is a reasonable option for those with a good response to NAST. Patients should undergo SLN mapping with a dual dye technique. Additionally, at least 2 lymph nodes should be removed, including the previously biopsied and marked lymph node with cancer. In this setting, the identification and false negative rates are acceptable. Patients found to have a negative SLN at this time may be spared the morbidity associated with ALND. Patients found to have persistently positive lymph nodes following NAST, either clinically or pathologically, should undergo a complete ALND.

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.

Mapping lymph nodes in cancer management - role of (99m)Tc-tilmanocept injection

Two decades ago, lymphatic mapping of sentinel lymph nodes (SLN) was introduced into surgical cancer management and was termed sentinel node navigated surgery. Although this technique is now routinely performed in the management of breast cancer and malignant melanoma, it is still under investigation for use in other cancers. The radioisotope technetium (^99mTc) and vital blue dyes are among the most widely used enhancers for SLN mapping, although near-infrared fluorescence imaging of indocyanine green is also becoming more commonly used. ^99mTc-tilmanocept is a new synthetic radioisotope with a relatively small molecular size that was specifically developed for lymphatic mapping. Because of its small size, ^99mTc-tilmanocept quickly migrates from its site of injection and rapidly accumulates in the SLN. The mannose moieties of ^99mTc-tilmanosept facilitate its binding to mannose receptors (CD206) expressed in reticuloendothelial cells of the SLN. This binding prevents transit to second-echelon lymph nodes. In Phase III trials of breast cancer and malignant melanoma, and Phase II trials of other malignancies, ^99mTc-tilmanocept had superior identification rates and sensitivity compared with blue dye. Trials comparing ^99mTc-tilmanocept with other ^99mTc-based agents are required before it can be routinely used in clinical settings.

Assessing the impact of neoadjuvant chemotherapy on the management of the breast and axilla in breast cancer

BACKGROUND

Nodal status is a sensitive prognostic indicator in breast cancer. Axillary metastases may be an indication for neoadjuvant systemic therapy. The aims of this study were to compare pathologic response rates to neoadjuvant chemotherapy (NAC) in the breast and axilla across different molecular subtypes of breast cancer and to compare the predictive value of axillary assessment before and after chemotherapy in determining final nodal status in this cohort of patients.

PATIENTS AND METHODS

The cohort comprised patients undergoing NAC from 2003 to November 2012. Data regarding patient and tumor characteristics, management, and outcomes were obtained from a prospectively maintained database and analyzed using PASW Statistics, version 18 (SPSS Inc, Chicago, IL).

RESULTS

Two hundred two cancers were identified in 196 patients. One hundred thirty-one (65%) diagnostic axillary procedures were performed, 105 (80%) before NAC, of which 93 (89%) were positive. In 28 (30%), downstaging was noted before NAC. Human epidermal growth factor receptor 2 (HER2) subtypes had the highest rate of complete pathologic response (n = 11 [61%]) and negative axillary clearance (AXCn) (n = 11 [69%]). Of 177 AXCns, 68 (38%) were negative before NAC.

CONCLUSION

AXCn in patients undergoing NAC remains controversial. HER2 subtypes are less likely to have axillary involvement after NAC and may demand different management.

Sentinel node biopsy for breast cancer: past, present, and future

Sentinel node biopsy has replaced axillary lymph node dissection as the standard of care in early breast cancers. Sentinel node biopsy represents a highly accurate and less-morbid axillary staging, which allows most patients to avoid unnecessary axillary lymph node dissection and its morbidity. This review provides information including several issues which are still under debate, such as clinical significance of micrometastases, avoidance of axillary lymph node dissection for patients with positive sentinel nodes, accuracy and timing of sentinel node biopsy in patients undergoing neoadjuvant chemotherapy, and how many sentinel nodes are sufficient for removal. Finally, a new topic is introduced: superparamagnetic iron oxide (SPIO)-enhanced magnetic resonance (MR) imaging for the detection of metastases in sentinel nodes localized by computed tomography (CT)-lymphography (CT-LG) in patients with breast cancer. SPIO-enhanced MR imaging is a useful method of detecting metastases in sentinel nodes localized by CT-LG in patients with breast cancer. Patients with clinically negative nodes may be spared even sentinel node biopsy when the sentinel node is diagnosed as disease free using SPIO-enhanced MR imaging.

Preoperative needle biopsy of sentinel lymph nodes using intradermal microbubbles and contrast-enhanced ultrasound in patients with breast cancer

OBJECTIVE

The purpose of this study was to assess whether sentinel lymph nodes (SLNs) that undergo targeted needle biopsy after identification by contrast-enhanced ultrasound (CEUS) using intradermally injected microbubbles results in more node-positive breast cancer patients being diagnosed preoperatively. Furthermore, we sought to determine whether the addition of CEUS to gray-scale sonography of the axilla reduces the number of patients having axillary lymph node (ALN) dissection as a second procedure.

SUBJECTS AND METHODS

Intradermal microbubble injection was performed in 136 breast cancer patients who had no abnormal ALNs on routine gray-scale axillary sonography. When an enhancing ALN was visualized, percutaneous sonography-guided fine-needle aspiration cytology or core needle biopsy was performed. Depending on the biopsy results, patients underwent SLN biopsy or ALN dissection. If the putative SLN biopsy was positive or a biopsy tract was seen in the excised SLN, the procedure was defined as successful.

RESULTS

SLNs were identified and biopsied in 126 of the 136 cases (93%). Seventeen patients had positive sonography-guided biopsy results (13%) and were treated with immediate ALN dissection. In seven patients, the biopsied node was the only positive node. The remaining 109 patients underwent SLN biopsy. In nine cases (8%), a positive lymph node was identified. Four of these false-negative cases had only micrometastases.

CONCLUSION

SLNs can be identified and biopsied using CEUS to increase the accuracy of preoperative axillary staging. If the needle biopsy result is negative, conventional SLN biopsy is indicated.

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.

Evaluation of sentinel node biopsy in locally advanced breast cancer patients who become clinically node-negative after neoadjuvant chemotherapy: a preliminary study

Introduction. Controversy continues over the appropriate timing of sentinel lymph node (SLN) biopsy in locally advanced breast cancer (LABC) patients receiving neoadjuvant chemotherapy. We evaluated the feasibility and accuracy of SLN biopsy in LABC patients with cytology-proven axillary nodal metastasis who become clinically node-negative after neoadjuvant chemotherapy. Materials. 30 consecutive patients with LABC, who had become clinically node-negative after 3 cycles of neoadjuvant chemotherapy, were included in the study. They were then subjected to SLN biopsy, axillary lymph node dissection, and breast surgery. Results. Sentinel nodes were successfully identified in 26 of the 30 patients, resulting in an identification rate of 86.67%, sensitivity of 83.33%, false negative rate of 20%, negative predictive value of 72.73%, and an overall accuracy of 88.46%. No complications were observed as a result of dye injection. Conclusions. SLN biopsy is feasible and safe in LABC patients with cytology-positive nodes who become clinically node-negative after neoadjuvant chemotherapy. Our accuracy rate, identification rate, and false negative rate are comparable to those in node-negative LABC patients. SLN biopsy as a therapeutic option in LABC after neoadjuvant chemotherapy is a promising option which should be further investigated.

Preoperative sentinel node identification with ultrasound using microbubbles in patients with breast cancer

OBJECTIVE

Sentinel lymph node (SLN) biopsy is the standard procedure for axillary staging in early breast cancer. Lymphatic imaging after peritumoral microbubble injection has been described in animal models. The aim of this study was to identify and localize SLNs preoperatively by contrast-enhanced sonography after intradermal injection of microbubbles in patients with breast cancer.

SUBJECTS AND METHODS

Eighty consecutive consenting patients with primary breast cancer were recruited. Patients received a periareolar intradermal injection of microbubble contrast agent. Breast lymphatics were visualized by sonography and followed to the axilla to identify SLNs. A guidewire was deployed to localize the SLN. The next day, patients underwent standard tumor excision and SLN biopsy.

RESULTS

In 71 (89%) of the 80 patients, SLNs were identified and guidewires were inserted. In these patients, operative findings using conventional radioisotope and blue dye techniques confirmed that the wired nodes were SLNs. Fourteen patients were found to have metastases in SLNs. In these patients, the SLNs were identified correctly and were localized with guidewires before surgery.

CONCLUSION

SLNs may be identified and localized before surgery using contrast-enhanced sonography after injection of microbubbles.