Axillary Nodal Burden in Breast Cancer Patients With Pre-operative Fine Needle Aspiration-proven Positive Lymph Nodes Compared to Those With Positive Sentinel Nodes

Accuracy of sentinel node mapping in patients with biopsy-proven metastatic axillary lymph nodes and upfront surgery: preliminary results of the Multimodal Targeted Axillary Surgery (MUTAS) trial

Background

Some studies suggested that the patients included in the Z0011 trial may represent patients with ultrasound-negative axillary nodes and axillary invasion diagnosed by sentinel node (SN) biopsy. Nevertheless, the National Comprehensive Cancer Network (NCCN) guidelines recommend SN mapping if 1 or 2 suspicious lymph nodes are identified on axillary ultrasound (AU). The aim of this preliminary phase of the Multimodal Targeted Axillary Surgery (MUTAS) trial was to establish the accuracy of SN mapping in patients with axillary involvement undergoing upfront surgery.

Methods

Between September 2019 and March 2022, we recruited patients with biopsy-proven metastatic axillary nodes and upfront surgery from a single center. We performed SN mapping in these patients before the surgical intervention, which included axillary lymph node dissection. The biopsy-proven metastatic node, SNs and the remaining axillary nodes were excised separately. SN status was considered representative of the status of the remaining axillary nodes. We calculated the sensitivity, specificity, negative predictive value and positive predictive value of the SN, overall and in patients with palpable nodes, in those with non-palpable nodes and an AU leading to diagnosis of axillary involvement, in those with 1 or 2 suspicious nodes on AU, and in patients with a single suspicious node on AU. We evaluated clinical, imaging and pathology features as predictors of the status of the remaining axillary nodes, false-negatives, and false-positives.

Results

We included 25 patients in this phase. The false-negative rate of SN mapping was 28% overall, 21.42% for patients with palpable nodes, 36.36% for patients with non-palpable nodes and an AU diagnosis of axillary involvement, 28.75% for those with 1 or 2 suspicious nodes on AU, and 15.38% in patients with a single suspicious node on AU. The negative predictive value was highest in patients with a single suspicious node on AU (75%). The only significant predictive factor was that FN showed a higher Ki67 index score.

Conclusions

In this study, SN mapping was not reliable in patients with biopsy-proven metastatic axillary nodes and upfront surgery for any of the subgroups studied. Further research should elucidate the best staging pathways in these patients to avoid premature de-escalation.

Higher risk tumor features are not associated with higher nodal stage in patients with estrogen receptor-positive, node-positive breast cancer

INTRODUCTION

Studies support omission of axillary lymph node dissection (ALND) for patients with sentinel node-positive disease, with ALND recommended for patients who present with clinically positive nodes. Here, we evaluate patient and tumor characteristics and pathologic nodal stage of patients with estrogen receptor-positive (ER +) breast cancer who undergo ALND to determine if differences exist based on nodal presentation.

MATERIALS AND METHODS

Retrospective chart review from 2010 to 2019 defined three groups of patients with ER + breast cancer who underwent ALND for positive nodes: SLN + (positive node identified at SLN biopsy), cNUS (abnormal preoperative US and biopsy), and cNpalp (palpable adenopathy). Patients who received neoadjuvant chemotherapy or presented with axillary recurrence were excluded.

RESULTS

Of 191 patients, 94 were SLN + , 40 were cNUS, and 57 were cNpalp. Patients with SLN + compared with cNpalp were younger (56 vs 64 years, p < 0.01), more often pre-menopausal (41% vs 14%, p < 0.01), and White (65% vs 39%, p = 0.01) with more tumors that were low-grade (36% vs 8%, p < 0.01). Rates of PR + (p = 0.16), levels of Ki67 expression (p = 0.07) and LVI (p = 0.06) did not differ significantly among groups. Of patients with SLN + disease, 64% had pN1 disease compared to 38% of cNUS (p = 0.1) and 40% of cNpalp (p = 0.01). On univariable analysis, tumor size (p = 0.01) and histology (p = 0.04) were significantly associated with pN1 disease, with size remaining an independent predictor on multivariable analysis (p = 0.02).

CONCLUSION

Historically, higher risk features have been attributed to patients with clinically positive nodes precluding omission of ALND, but when restricting evaluation to patients with ER + breast cancer, only tumor size is associated with higher nodal stage.

Assessing the Burden of Nodal Disease for Breast Cancer Patients with Clinically Positive Nodes: Hope for More Limited Axillary Surgery

BACKGROUND

Omission of axillary lymph node dissection (ALND) is accepted for patients with one or two positive sentinel nodes, and studies are focusing on clinically node-positive patients who have been downstaged with neoadjuvant chemotherapy (NAC). Evidence is lacking for patients with positive nodes who undergo surgery upfront. These patients are assumed to have a higher burden of nodal disease such that ALND remains the standard of care.

METHODS

Patients who underwent ALND for breast cancer between 2010 and 2019 at the authors' institution were retrospectively identified. Those with clinical N1 disease were included in the study. Patients who received NAC and those who had surgery for sentinel node positive disease or axillary recurrence were excluded. Clinical and pathologic factors associated with nodal stage were evaluated.

RESULTS

Of 111 patients who met the inclusion criteria, 61.3% had a palpable node on exam, and 41.4% ultimately had pN1 disease. Most of the tumors were estrogen receptor (ER)-positive (91.5%), and 21.7% of the tumors were invasive lobular cancers. Lobular histology, tumor size, and metastasis size were associated with higher nodal stage. In the multivariable analysis, the patients with nodal metastasis larger than 10 mm had significantly lower odds of having pN1 disease (odds ratio 0.12; 95% confidence interval 0.02-0.69; p = 0.02). In a subset analysis of patients with palpable nodes, tumor size and histology remained significantly associated with nodal stage.

CONCLUSION

More than 40% of breast cancer patients with clinically positive nodes had minimal nodal disease (pN1) at surgery. Additionally, palpable nodes on exam did not predict higher nodal stage. A subset of patients with clinically positive nodes may be identified who can potentially be spared the morbidity of ALND.