Pathological evaluation of sentinel lymph nodes in breast cancer: a practical academic perspective from America

Positive non-sentinel axillary lymph nodes in breast cancer with 1-2 sentinel lymph node metastases

Recent clinical trials have shown that sentinel lymph node biopsy (SLNB) alone without axillary lymph node dissection (ALND) can offer excellent regional control if there is sentinel lymph nodes (SLN) metastases to 1-2 nodes. This study aimed to explore the predictive factors for non-sentinel lymph node (NSLN) metastasis in breast cancer patients with 1-2 positive SLNs.Patients with breast cancer and 1-2 positive SLN admitted between March 2009 and March 2017 and who underwent ALND after SLN biopsy (SLNB) at Beijing Chaoyang Hospital were analyzed retrospectively. Factors influencing the status of NSLN were studied by univariate and multivariate analysis.Of 1125 patients, 147 patients had SLN metastasis (13.1%) and 119 patients (81.0%) had 1-2 positive SLNs. Among them, 42 patients (35.3%) had NSLN metastasis. The invasive tumor size (P <.001), histological grade (P =.011), lymphovascular invasion (LVI) (P =.006), and over-expression of HER2 (P =.025) significantly correlated with non-SLN metastasis by univariate analysis. LVI (LVI) (P =.007; OR: 4.130; 95% confidence interval [CI]: 1.465-11.641), invasive tumor size (P <.001; OR: 7.176; 95% CI: 2.710-19.002), and HER2 over-expression (P =.006; OR: 5.489; 95% CI: 1.635-18.428) were independently associated with NSLN metastasis by the Logistic regression model. The ROC analysis identified a cut-off point of 26 mm of tumor size (area under the receiver operating characteristic [ROC] curve [AUC] 0.712, CI: 0.614-0.811) was useful for dividing patients with positive SLN (1-2 nodes) into non-SLN-positive and non-SLN-negative groups.For 1-2 positive SLNs of breast cancer, LVI, large invasive tumor size, and HER2 over-expression are independent factors affecting NSLN metastases.

Evaluation of the Probability of Non-sentinel Lymph Node Metastasis in Breast Cancer Patients with Sentinel Lymph Node Metastasis using Two Different Methods

OBJECTIVE

The aim of this retrospective clinical study was to evaluate the accuracy and feasibility of two different clinical scales, namely the Memorial Sloan-Kettering Cancer Center (MSKCC) nomogram and Tenon's axillary scoring system, which were developed for predicting the non-sentinel lymph node (NSLN) status in our breast cancer patients.

MATERIAL AND METHODS

The medical records of patients who were diagnosed with breast cancer between January 2010 and November 2013 were reviewed. Those who underwent sentinel lymph node biopsy (SLNB) for axillary staging were recruited for the study, and patients who were found to have positive SLNB and thus were subsequently subjected to axillary lymph node dissection (ALND) were also included. Patients who had neoadjuvant therapy, who had clinically positive axilla, and who had stage 4 disease were excluded. Patients were divided into two groups. Group 1 included those who had negative NSLNs, whereas Group 2 included those who had positive NSLNs. The following data were collected: age, tumor size, histopathological characteristics of the tumor, presence of lymphovascular invasion, presence of multifocality, number of negative and positive NSLNs, size of metastases, histopathological method used to define metastases, and receptor status of the tumor. The score of each patient was calculated according to the MSKCC nomogram and Tenon's axillary scoring system. Statistical analysis was conducted to investigate the correlation between the scores and the involvement of NSLNs.

RESULTS

The medical records of patients who were diagnosed with breast cancer and found to have SLNB for axillary staging was reviewed. Finally, 50 patients who had positive SLNB and thus were subsequently subjected to ALND were included in the study. There were 17 and 33 patients in Groups 1 and 2, respectively. Both the MSKCC nomogram and Tenon's axillary scoring system were demonstrated to be significantly accurate in the prediction of the involvement of NSLNs (p<0.05 for each). Among all the parameters, the only one that was found to be correlated with the risk of NSLN involvement was the presence of lymphovascular invasion.

CONCLUSION

The MSKCC nomogram and Tenon's axillary scoring system both seem to be reliable tools for the assessment of NSLN status in SLNB-positive breast cancer in our breast cancer population. Nevertheless, the omission of ALNB in SLNB-positive breast cancer cannot be yet recommended because of the lack of long-term results of current nomograms and scoring systems.

Pathological controversies in breast cancer: classification of ductal carcinoma in situ, sentinel lymph nodes and low volume metastatic disease and reporting of neoadjuvant chemotherapy specimens

The pathological classification of breast cancer is constantly being updated to reflect the advances in our clinical and biological understanding of the disease. This overview examines new insights into the classification and molecular biology of ductal carcinoma in situ, the pathological handling of sentinel lymph node biopsies and the identification of low volume disease (micrometastases and isolated tumour cells) and the handling and reporting of specimens after neoadjuvant therapy. The molecular subtypes of invasive breast cancer are also represented in ductal carcinoma in situ. It is hoped that alongside traditional histological features, such as cytological grade and the presence of necrosis, this will lead to better classification systems with improved prediction of clinical behaviour, in particular the risk of progression to invasive cancer, and enable more targeted management. Sentinel lymph node biopsy is now the standard of care for early stage breast cancer in clinically node-negative patients. However, the handling and reporting of these specimens remains controversial, largely related to the uncertainties regarding the clinical significance of micrometastases and isolated tumour cells. The increasing use of neoadjuvant therapies has introduced challenges for the pathologist in the handling and interpretation of these specimens. Grading the tumour response, particularly the identification of a complete pathological response, is prognostically important. However, there is still marked variability in reporting these specimens in routine practice, and consensus guidelines for the histopathology reporting of breast cancers after neoadjuvant chemotherapy based on robust, validated evidence are presently lacking.

Molecular assessment of sentinel lymph node in breast cancer management

Sentinel lymph node biopsy (SLNB) is becoming accepted as standard of care for axillary staging in breast cancer. World Health Organization (WHO) re-classification of axillary metastases into macrometastases, micrometastases and individual tumour cells has highlighted the issues of sampling and further histological examination of the initially negative SLNB. Molecular detection of metastatic breast cancer cells in lymph nodes is now available as a commercial kit for intraoperative use and can resolve the sampling issue. Semiquantitative assessment of axillary lymph node tumour burden can now be made using two separate technologies (histology and reverse transcriptase-polymerase chain reaction). The clinical implications of low metastatic axillary lymph node tumour burden are not clear, and future trials need to include molecular data. The consequences of the availability of molecular assessment are reviewed.

Does the introduction of sentinel node biopsy increase the number of node positive patients with early breast cancer? A population based study form the Danish Breast Cancer Cooperative Group

BACKGROUND

The validation series of sentinel lymph node biopsy (SLNB) in the treatment of breast cancer have shown that 10-20% more lymph node metastases are detected. However, their impact has never been studied in populations where the method has been fully implemented. In a population-based setting, the objective of the current study was to estimate the increased risk of metastases after introduction of the sentinel lymph node biopsy technique.

METHODS

We identified all new breast cancer patients in three different counties in two time periods (1996-1997 and 2002-2003). The study cohort was comprised of 2 932 patients. The main outcome was the frequency of patients with metastases. The frequencies of patients with metastases were compared as well as adjusted (using a multivariate logistic regression) and unadjusted odds-ratio for detecting lymph node metastases.

RESULTS

In counties where sentinel lymph node biopsy was implemented, the frequency of patients with lymph node metastases increased significantly 7.3% (95% CI: 1.0-13.7%) and 13.3% (95% CI: 7.3-19.3%), respectively. In the county without sentinel lymph node biopsy, an insignificant increase of 6.9% (-0.1-13.9%) in the frequency of patients with metastases was seen. The adjusted odds- ratio for detecting lymph node metastases was 1.41 (1.07-1.87) and 1.70 (1.30-2.23) in the counties with SLNB.

CONCLUSION

The frequency of patients with metastases increased significantly in counties where sentinel lymph node biopsy was implemented.

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.

Immunohistochemistry on frozen section of sentinel lymph nodes in breast cancer with improved morphology and blocking of endogenous peroxidase

Sentinel lymph node biopsy in the management of patients with breast cancer is the clinical practice. Peroperative examination means that more patients can be treated in a 1-step procedure. The addition of immunohistochemistry to frozen section slides improves the detection rate of especially micrometastasis. We present a novel method for immunohistochemical staining on a frozen section material that gives better morphology and blocks endogenous peroxidase sufficiently.

Pathologic examination of sentinel lymph nodes in breast cancer by a single haematoxylin-eosin slide versus serial sectioning and immunocytokeratin staining: clinical implications

BACKGROUND

The objective was to determine the additional value of pathologic examination using three-level sectioning and immunocytokeratin (ICK) staining of sentinel lymph node (SN) biopsies in cT1-2N0M0 breast carcinoma patients regarding lymph node staging and eligibility of systemic therapy taking primary tumor characteristics in account.

METHODS

SN slides of 277 patients out of a total group of 961 patients known to have tumor-positive SNs detected by three-level sectioning and ICK staining were re-examined. Haematoxylin-eosin (HE) slide level three was scanned for tumor deposits, and when present, extra capsular extension, maximum tumor diameter and number of positive SNs was noted. In addition, slides of the axillary dissection of non-SNs were reviewed, with determination of metastasis size and number of positive non-SNs. Primary tumor characteristics (grade, diameter, estrogen receptor) were recorded.

RESULTS

In the single-HE examination, 26 cases SN micrometastasis and 6 macrometastasis were missed, 3 cases of micrometastasis were incorrectly classified as isolated tumor cells, and 9 patients with macrometastasis were misclassified as micrometastasis. In addition, in the tumor-negative single-HE examination, additional axillary lymph node dissection (ALND) revealed 6 cases of non-SN metastasis. Taking primary tumor factors into account for adjuvant systemic therapy, 21 patients would have been denied the choice for systemic therapy if single-HE examination was carried out only.

CONCLUSIONS

Single-HE examination of SN may result in a reduction of locoregional and systemic treatment according to treatment guidelines then current in the Netherlands.

Intramammary lymph nodes and breast cancer: a marker for disease severity, or just another lymph node?

BACKGROUND

Axillary lymph node status is still considered the most significant prognostic factor for breast cancer outcome, and treatment decisions are based on the presence or absence of nodal disease. Intramammary lymph nodes (IMLNs) can be a site of regional spread. Is this a marker for more aggressive disease?

METHODS

We reviewed the cancer center pathology database from 1991 to 2005 for all cases of breast cancer with IMLNs.

RESULTS

IMLNs were identified in 64 breast cancer patients, with metastatic spread in 20 patients, and benign IMLNs described in 44 patients. Positive IMLNs were associated with more aggressive disease, including higher rates of invasive versus noninvasive cancers (5% ductal carcinoma-in-situ [DCIS] with positive IMLNs vs. 23% with negative IMLNs), lymphovascular invasion (55% vs. 11%), and a higher rate of axillary lymph node involvement (72% vs. 18%). Patients with positive IMLNs were also more likely to undergo mastectomy (75% vs. 54%).

CONCLUSIONS

IMLN metastases are a marker for disease severity; recognition of this may influence choice of adjuvant therapy. The presence of metastatic disease in an IMLN is associated with a high rate of axillary nodal involvement, and should mandate axillary dissection. Preoperative lymphoscintigraphy may help identify these extra-axillary metastases.

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

New techniques and treatments in medicine occasionally take on a life of their own. Sometimes, an idea's use is inherently obvious from the outset, sometimes not, in which case it becomes technology in search of an application. Identification of sentinel lymph nodes in breast cancer is a combination of these two options: to some extent the technique has been overused and its results overinterpreted. 10 years after the procedure's introduction and general acceptance, a few issues still deserve further discussion despite much published work on this topic. Use of sentinel-lymph-node identification has been extended to other organ systems, yet not all the lessons learned in the breast might apply to other sites. Review of the theory behind the technique and breast cancer experience to date is important. Many of the published controversies about sentinel lymph nodes in breast cancer can be resolved by consideration of the basic ideas underlying the procedure, which is the aim of this Essay.

Detection of occult sentinel lymph node micrometastases by immunohistochemistry in breast cancer

BACKGROUND

Occult metastases, by definition, are not detected on initial examination. They may be present on slides but missed during screening or may be present in paraffin embedded tissue blocks and undetected without additional levels. Anticytokeratin immunohistochemistry (CK IHC) enhances detection of occult metastases, particularly micrometastases (> 0.2 mm but not larger than 2.0 mm) or isolated tumor cell clusters (< or = 0.2 mm). This study defines the rate at which pathologists miss metastases on CK IHC of sentinel lymph nodes (SLN).

METHODS

CK IHC sections 0.5 and 1.0 mm from the original surface of SLN tissue blocks were screened by pathologists using standard bright field light microscopes (LM) and by supervised computer assisted cell detection (CACD). All blocks were from breast cancer patients, initially classified 'node negative' on review of routinely stained sections from the surface of each block. Cases missed by LM screening but detected by CACD defined false negative screens.

RESULTS

Of 236 cases screened, LM detected 34 (14.4%; 95% CI: 9.6-20.2) cases and, in the 202 cases negative by LM, CACD detected an additional 30 (14.9%; 95% CI: 9.6-21.2%) cases with occult metastases. Occult metastases missed by LM screening ranged from 0.01 to 0.1 mm in greatest dimension. The probability of missing an occult metastasis < or = 0.02 mm; < or = 0.05 mm, and < or = 0.10 mm was 75%, 69.2%, and 61.2%, respectively. No occult metastases larger than 0.10 mm were missed by LM screening.

CONCLUSIONS

Pathologists screening the CK IHC stained slides may frequently miss detecting metastases < 0.10 mm.