Sentinel lymph nodes in breast cancer after 10 years: rethinking basic principles

Total Tumor Load of mRNA Cytokeratin 19 in the Sentinel Lymph Node as a Predictive Value of Axillary Lymphadenectomy in Patients with Neoadjuvant Breast Cancer

Although sentinel lymph node biopsy (SLNB) has proved to be able to diagnose axillary lymph node status safely and reliably, there is still not enough evidence to suggest that it can be used in patients who have undergone neoadjuvant chemotherapy (NAC) for lymph node-sparing surgery. The present study used molecular approaches to determine whether SLNB can be reliably used in patients who have been treated with NAC before SLN surgery, and whether the total tumor load of the SLN can be used as a predictive factor in axillary lymphadenectomy (ALD). We used one-step nucleic acid amplification (OSNA) to analyze a total of 111 consecutive patients who presented operable invasive breast carcinomas and who had been treated with NAC. SLN was positive in 55 patients and the identification rate was 100%. In 9 of these 55 patients, ALD showed that other lymph nodes were also involved. In all of the other 46 patients, the only lymph node to be identified as positive was SLN. Metastasis was not found in any of the axillary lymph nodes in the isolated tumor cell group. The total tumor load, defined as the amount of cytokeratin 19 mRNA copy numbers in all positives SLN (copies/µL), showed three risk groups related to the possibility of positive non-sentinel nodes. OSNA is a diagnostic technique that is highly sensitive, specific, and reproducible and it can be used to analyze sentinel lymph nodes after NAC. Total tumor load may be able to help predict additional metastases in axillary lymphadenectomy.

Accuracy of Intraoperative Frozen Section of Sentinel Lymph Nodes After Neoadjuvant Chemotherapy for Breast Carcinoma

False-negative (FN) intraoperative frozen section (FS) results of sentinel lymph nodes (SLN) have been reported to be more common after neoadjuvant chemotherapy (NAC) in the primary surgical setting. We evaluated SLN FS assessment in breast cancer patients treated with NAC to determine the FN rate and the histomorphologic factors associated with FN results. Patients who had FS SLN assessment following NAC from July 2008 to July 2017 were identified. Of the 711 SLN FS cases, 522 were negative, 181 positive, and 8 deferred. The FN rate was 5.4% (28/522). There were no false-positive results. Of the 8 deferred cases, 5 were positive on permanent section and 3 were negative. There was a higher frequency of micrometastasis and isolated tumor cells in FN cases (P<0.001). There was a significant increase in tissue surface area present on permanent section slides compared with FS slides (P<0.001), highlighting the inherent technical limitations of FS and histologic under-sampling of tissue which leads to most FN results. The majority (25/28, 89%) of FN cases had metastatic foci identified exclusively on permanent sections and were not due to a true diagnostic interpretation error. FN cases were more frequently estrogen receptor positive (P<0.001), progesterone receptor positive (P=0.001), human epidermal growth factor receptor-2 negative (P=0.009) and histologic grade 1 (P=0.015), which most likely reflects the lower rates of pathologic complete response in these tumors. Despite its limitations, FS is a reliable modality to assess the presence of SLN metastases in NAC treated patients.

Use of Mastectomy for Overdiagnosed Breast Cancer in the United States: Analysis of the SEER 9 Cancer Registries

Aim

We investigated use of mastectomy as treatment for early breast cancer in the US and applied the resulting information to estimate the minimum and maximum rates at which mastectomy could plausibly be undergone by patients with overdiagnosed breast cancer. Little is currently known about overtreatments undergone by overdiagnosed patients.

Methods

In the US, screening is often recommended at ages ≥40. The study population was women age ≥40 diagnosed with breast cancer in the US SEER 9 cancer registries during 2013 (n=26,017). We evaluated first-course surgical treatments and their associations with case characteristics. Additionally, a model was developed to estimate probability of mastectomy conditional on observed case characteristics. The model was then applied to evaluate possible rates of mastectomy in overdiagnosed patients. To obtain minimum and maximum plausible rates of this overtreatment, we respectively assumed the cases that were least and most likely to be treated by mastectomy had been overdiagnosed.

Results

Of women diagnosed with breast cancer at age ≥40 in 2013, 33.8% received mastectomy. Mastectomy was common for most investigated breast cancer types, including for the early breast cancers among which overdiagnosis is thought to be most widespread: mastectomy was undergone in 26.4% of in situ and 28.0% of AJCC stage-I cases. These rates are substantively higher than in many European nations. The probability-based model indicated that between >0% and <18% of the study population could plausibly have undergone mastectomy for overdiagnosed cancer. This range reduced depending on the overdiagnosis rate, shrinking to >0% and <7% if 10% of breast cancers were overdiagnosed and >3% and <15% if 30% were overdiagnosed.

Conclusions

Screening-associated overtreatment by mastectomy is considerably less common than overdiagnosis itself but should not be assumed to be negligible. Screening can prompt or prevent mastectomy, and the balance of this harm-benefit tradeoff is currently unclear.

De-escalation of axillary surgery in early breast cancer

With the advent of sentinel lymph node biopsy, surgical methods for accurately staging the axilla in patients with early-stage breast cancer have become progressively less extensive, with formal axillary lymph node dissection confined to a dwindling group of patients. Although details of methods for sentinel lymph node biopsy have yet to be standardised, this technique is now widely practised and accepted as standard of care worldwide. In the past 5 years, attention has focused on minimisation of surgical morbidity by restricting further axillary surgery or considering radiotherapy in patients with a small tumour burden in their sentinel nodes. This change in approach to patients with positive sentinel lymph node biopsies has increased the complexity of axillary management, and any policy of de-escalation and avoidance of morbidity must not compromise patient outcomes. This trend for de-escalation has accompanied a shift in understanding of how any residual tumour burden can be adequately managed without surgical extirpation and reliance on effective adjuvant therapies. Indications for omission of completion axillary lymph node dissection in patients with two or fewer nodes containing macrometastases demand further clarification, together with the roles of preoperative imaging in defining axillary nodal burden, deselection of patients for sentinel lymph node biopsy, and provision of radiotherapy. Downstaging of biopsy-proven node-positive patients with neoadjuvant chemotherapy could safely permit sentinel lymph node biopsy alone when the index node has been successfully retrieved at surgery, while nodal deposits of any size continue to mandate completion axillary lymph node dissection. Developments in molecular imaging technologies and percutaneous biopsy techniques could potentially render sentinel lymph node biopsy redundant in the future.

Intraoperative molecular analysis of sentinel lymph nodes following neoadjuvant chemotherapy in patients with clinical node negative breast cancer: An institutional study

Sentinel lymph node biopsy (SLNB) is an accurate, safe method for determining the axillary lymph node status. However, insufficient evidence exists to support the recommendation of SLNB in patients who have had neoadjuvant chemotherapy (NAC) to downsize tumours and allow for breast conservation surgery. The present study aimed to use molecular approaches to evaluate the feasibility and accuracy of SLNB in patients treated with NAC prior to SLN mapping and surgery. A total of 50 consecutive patients with operable invasive breast carcinomas who had received prior NAC were assessed using the one-step nucleic acid amplification (OSNA) method. The rate of SLN identification was 100%. The OSNA assay showed that 29 patients (58%) were negative for SLN and 21 patients (42%) were positive. In 19 of these 21 patients (90.48%), the SLN was the only positive lymph node. No axillary lymph nodes metastases were observed in patients with isolated tumour cells or with micrometastases. The OSNA assay is a highly sensitive, specific and reproducible diagnostic technique that can be used to analyse SLNs following NAC. The total tumoral load may assist with predicting additional non-SLN metastases.

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.

Characteristics of breast carcinoma cases with false-negative sentinel lymph nodes

BACKGROUND

In the past decade, sentinel lymph node biopsy (SLNB) has become standard for patients with early-stage clinically node-negative breast carcinoma (BC). Despite high overall surgical identification success rates with introduction of the dual-tracer techniques (dye and radiolabeled probe), false-negative rates remained unchanged in most recent meta-analyses.

PATIENTS AND METHODS

We analyzed cases with false-negative SLN biopsy results over a 12-year period in a single institution to evaluate their clinicopathologic characteristics. Sixty-three false-negative cases (3.1%) were found in 2043 successful SLN mapping procedures, all of which were followed by varying amounts of additional axillary sampling.

RESULTS

There was a higher proportion of invasive lobular carcinomas (ILCs; 23 cases [37%]) when compared with this lesion's overall reported frequency (5%-15%). The majority of invasive ductal carcinoma (IDC) cases (31 of 40) were poorly differentiated. In 80% of the ductal-type cases, 1 or more nonsentinel nodes (NSLNs) were completely or partially replaced by tumor, as opposed to less than half of such cases of the lobular type. Twenty-two cases had multiple positive NSLN metastases, which were significantly associated with larger tumor size (≥ 1.0 cm) and tumor replacement of NSLNs. Eighty-two percent of the cases with known hormone receptor status were positive for estrogen or progesterone receptors, or both.

CONCLUSION

False-negative SLN biopsy results were more often associated with a primary BC characterized by a lobular or poorly differentiated ductal histologic type or partial to complete replacement of NSLNs with tumor, or both.

Novel handheld PET probes provide intraoperative localization of PET-avid lymph nodes

INTRODUCTION

The accurate intraoperative localization of malignant nodes can pose a challenge to the surgical oncologist. Positron emission tomography (PET) scanning has significantly increased our ability to detect suspicious lesions. We investigated the ability of a novel, handheld tool to evaluate suspicious nodes intraoperatively and to correlate its findings with those seen on preoperative PET scan.

METHODS

Ten nude rats were inoculated with a lymphogenic mesothelioma tumor line and followed weekly with PET scan studies. When suspicious lymph nodes were found, animals were dissected and the intraoperative amount of tissue radiation was analyzed as "tumor-to-background ratio" (TBR) using the PET probes.

RESULTS

The intraoperative probe was used to guide dissections and select high-risk nodes based on their specific radiotracer uptake. A total of 52 nodes were harvested; eight of these were suspicious on preoperative PET scan studies. Using a TBR of 2.5, the intraoperative probes were able to localize all suspicious nodes previously seen on PET scan. Both gamma (sensitivity: 100%; specificity: 86%; positive predictive value (PPV): 57%; negative predictive value (NPV): 100%) and beta (sensitivity: 88%; specificity: 91%; PPV: 64%; NPV: 98%) probes showed an excellent area under the curve (AUC) in the receiver operating characteristic analysis (ROC). Both probes had an AUC of 0.95 for localizing suspicious nodes on PET scan. Furthermore, the AUC for detecting malignancy for the gamma probe was 0.90 (95% confidence interval (CI), 0.83-0.99), and for the beta probe it was 0.97 (95% CI, 0.94-1.0), suggesting a better performance of the beta probe for detecting malignancy.

CONCLUSIONS

This novel tool may be used synergistically with the PET scan examination to maximize intraoperative nodal selection and sampling.

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.

Intraoperative consultation for axillary sentinel lymph node biopsy: an 8-year audit

To summarize the authors' 8-year institutional experience with intraoperative consultation via frozen section (FS) on sentinel lymph node biopsy (SLNB) in breast cancer patients we recorded the, complete operative procedure including additional surgery on the ipsilateral axilla and intraoperative consultation and permanent histopathologic processing for all cases with inoperative consultation on SLNB in breast cancer patients between the groups, chi(2) and Fisher's exact tests were used. Intraoperative consultation was positive in 116/706 cases (16.4%) and final pathology in 158/706 cases (22.4%); the false-negative rate was 26.6%, the false-positive rate was 0%, and the overall accuracy was 94%. False-negative rate was significantly associated with the size of metastasis (micro vs macrometastasis; P < .002) but not significantly associated with the histologic type (P = 0.76) or pathologist expertise (P = 0.08). The rate of spared second procedures was 92% when calculated exclusively for patients who ultimately underwent ALND. Intraoperative consultation via FS for SLNB is a safe practice that can reliably save clinically node-negative patients a second surgery.

Optimization of sentinel lymph node biopsy in breast cancer using an operative gamma camera

Background

Sentinel lymph node (SLN) procedure is now a widely accepted method of LN staging in selected invasive breast cancers (unifocal, size ≤ 2 cm, clinically N0, without previous treatment). Complete axillary clearance is no longer needed if the SLN is negative. However, the oncological safety of this procedure remains to be addressed in randomized clinical trials. One main pitfall is the failure to visualize SLN, resulting in incorrect tumor staging, leading to suboptimal treatment or axillary recurrence. Operative gamma cameras have therefore been developed to optimize the SLN visualization and the quality control of surgery.

Case presentation

A 44-year-old female patient with a 14-mm infiltrative ductal carcinoma underwent the SLN procedure. An operative gamma camera was used during and after the surgery. The conventional lymphoscintigraphy showed only one SLN, which was also detected by the operative gamma camera, then removed and measured (9.6 kBq). It was analyzed by frozen sections, showing no cancer cells. During this analysis, the exploration of the axillary area with the operative gamma camera enabled the identification of a second SLN with low activity (0.5 kBq) that conventional lymphoscintigraphy, surgical probe and blue staining had failed to visualize. Histological examination revealed a macrometastasis. Axillary clearance was then performed, followed by a postoperative image proving that no SLN remained. Therefore, the use of the operative gamma camera prevented an under-estimation of staging which would have resulted in a suboptimal treatment for this patient.

Conclusion

This case report illustrates that an efficient operative gamma camera may be able to decrease the risk of false negative rate of the SLN procedure, and could be an additional tool to control the quality of the surgery.

Trial Registration

ClinicalTrials.gov Identifier: NCT00357487

Factors affecting false-negative breast sentinel node biopsy in Chinese patients

BACKGROUND

The objective of the research was to validate our results on sentinel lymph node biopsy (SLNB) and to determine factors affecting false-negative (FN) rates of SLNB in Chinese patients with invasive breast cancers.

METHODS

A retrospective study of patients with clinically node-negative invasive breast cancer was carried out from May 1999 to April 2006. A combination of radioisotope (99m)technetium(Tc)-albumin sulfur colloid and Patent Blue V dye was used to identify the sentinel lymph node. Sentinel lymph node biopsy was followed by standard level I and II axillary dissection in all patients. Various clinicopathologic variables were analysed to determine factors associated with FN SLNB.

RESULTS

Three hundred and sixty-five Chinese patients received SLNB consecutively during the study period. Seventy-eight patients with neoadjuvant chemotherapy and 56 patients with in situ carcinoma were excluded. A total of 231 patients were studied. Sentinel lymph nodes were identified in 221 patients (95.7%). There were 10 FN, resulting in a FN rate of 12.5% and accuracy rate of 95.5%. Only the number of sentinel lymph node harvested was found to be a significant factor affecting FN rates on univariate (P < 0.009) and multivariate logistic regression (odds ratio: 2.65; 95% confidence interval: 2.57-2.73; P < 0.000).

CONCLUSIONS

In Chinese women, after this retrospective analysis of available findings, at least should sentinel nodes should be removed to reduce risk of false negativity.

Standardizing Slide-Based Assays in Breast Cancer: Hormone Receptors, HER2, and Sentinel Lymph Nodes

Despite the rapid expansion of novel diagnostics designed to personalize breast cancer care, there remain several significant unmet needs for improving the accuracy and reliability of tests that are already in common daily clinical practice. For example, although immunohistochemistry has been the predominant method for measuring estrogen receptor and progesterone receptor status for over 15 years, this assay remains unstandardized and there is a widespread concern that inaccuracy in immunohistochemistry technique and interpretation is leading to an unacceptably high error rate in determining the true hormone receptor status. Similarly, there is considerable concern that both false-negative and false-positive result rates for testing for HER2 status are unacceptably high in current clinical practice. This commentary considers a variety of factors, including preanalytic conditions and slide-scoring procedures, and other variables that may be contributing to current testing error rates and why there is a great need for the standardization of these biomarker assay procedures to further enable the highest possible quality of care for newly diagnosed breast cancer patients.

Management of the axilla in women with breast cancer

The approach towards axillary surgery should be selective and flexible, with its management tailored to patient choice and tumour characteristics, and concordant with local practice guidelines and available resources. Sentinel-lymph-node biopsy has been embraced as a standard of care in many centres around the world and has revolutionised management of the axilla during the past decade. Nonetheless, data for long-term outcomes remain scarce, and there are persistent variations in practice and inconsistencies in methodology. An international perspective has been sought on important issues relating to management of the axilla, which includes not only the indications and techniques for sentinel-lymph-node biopsy, but also lymph-node sampling, axillary-lymph-node dissection, and observation alone. In this Review, we initially present an overview, which focuses on biological models of lymphatic networks within the breast and patterns of tumour dissemination. A set of key questions are posed with preliminary comments from the authors, followed by a series of collective viewpoints from experts within several different countries.

Sentinel lymph node biopsy in staging small (up to 15 mm) breast carcinomas. Results from a European multi-institutional study

Sentinel lymph node (SLN) biopsy has become the preferred method for the nodal staging of early breast cancer, but controversy exists regarding its universal use and consequences in small tumors. 2929 cases of breast carcinomas not larger than 15 mm and staged with SLN biopsy with or without axillary dissection were collected from the authors' institutions. The pathology of the SLNs included multilevel hematoxylin and eosin (HE) staining. Cytokeratin immunohistochemistry (IHC) was commonly used for cases negative with HE staining. Variables influencing SLN involvement and non-SLN involvement were studied with logistic regression. Factors that influenced SLN involvement included tumor size, multifocality, grade and age. Small tumors up to 4 mm (including in situ and microinvasive carcinomas) seem to have SLN involvement in less than 10%. Non-SLN metastases were associated with tumor grade, the ratio of involved SLNs and SLN involvement type. Isolated tumor cells were not likely to be associated with further nodal load, whereas micrometastases had some subsets with low risk of non-SLN involvement and subsets with higher proportion of further nodal spread. In situ and microinvasive carcinomas have a very low risk of SLN involvement, therefore, these tumors might not need SLN biopsy for staging, and this may be the approach used for very small invasive carcinomas. If an SLN is involved, isolated tumor cells are rarely if ever associated with non-SLN metastases, and subsets of micrometastatic SLN involvement may be approached similarly. With macrometastases the risk of non-SLN involvement increases, and further axillary treatment should be generally indicated.