The use of cytokeratin staining in sentinel lymph node biopsy for breast cancer

Immunocytochemical markers, molecular testing and digital cytopathology for aspiration cytology of metastatic breast carcinoma

Fine-needle aspiration cytology (FNAC) is a versatile diagnostic procedure uniquely suited for tissue biopsy of breast carcinomas and axillary metastases and/or recurrences. With the expanding treatment options and accompanying theragnostic tests, it is crucial to recognize the developments on ancillary testing and digital cytopathology techniques related to aspiration cytology of metastatic breast carcinoma. In this review, we aim to summarize and update the evidence of immunocytochemistry, for the detection of carcinoma cells (epithelial markers), confirmation of breast primary (breast-specific markers), assessment of surrogate immunostains (hormone receptors, ki-67 proliferative index and HER2) and theragnostic biomarkers, with discussion on potential diagnostic pitfalls, followed by the application of molecular tests, and digital cytopathologic techniques for assessing metastatic breast carcinoma in cytology.

Lack of Clinical Value for Immunohistochemistry for Sentinel Lymph Node Assessment in Invasive Lobular Carcinoma

BACKGROUND

The distinct histologic appearance of invasive lobular carcinoma (ILC) may pose diagnostic challenges for sentinel lymph node (SLN) analysis. We evaluated the impact of cytokeratin immunohistochemistry (IHC) on SLN assessment in ILC and its contribution to pathologic nodal upstaging.

METHODS

We identified ILC patients treated with SLN surgery at our institution between September 2008 and August 2021. IHC for SLN assessment was employed at the discretion of the pathologist. Differences between groups evaluated with and without IHC were compared using Chi-square tests.

RESULTS

Overall, 608 cases of ILC were identified in patients who underwent SLN surgery. IHC was used in 301 cases (49.5%) and was not associated with cT category, pT category, or tumor grade. Use of IHC increased detection of SLN+ disease when isolated tumor cells (ITCs) were included in the analysis (35.9% with IHC vs. 21.2% without IHC; p < 0.001). There was no effect on nodal upstaging to micrometastatic disease (pN1mi) or greater (21.9% with IHC vs. 21.2% without IHC; p = 0.82). IHC did not increase the number of positive SLNs detected (median 1 with and without IHC) nor did it increase axillary lymph node dissection (ALND) rates (11.6% with IHC vs. 15.3% without IHC; p = 0.18).

CONCLUSION

IHC improved detection of pN0(i+) disease among ILC patients undergoing SLN surgery. IHC did not increase upstaging to pN1mi or higher categories of nodal disease, detection of a greater number of positive SLNs, or ALND rates. Our data suggest routine use of IHC for SLN assessment in ILC patients does not add clinical utility.

Adjuvant chemotherapy for breast cancer patients with axillary lymph node micrometastases

BACKGROUND

The axillary lymph node status is one of the most important prognostic factors in patients with early breast cancer. However, the impact of axillary lymph node micrometastases on survival remains unclear. There are no consistent recommendations for adjuvant chemotherapy (CHT). In this context, we aimed to investigate the impact of micrometastases on the clinical outcome of breast cancer patients according to the adjuvant CHT performed.

PATIENTS AND METHODS

We conducted a retrospective population-based registry study of 26,465 patients aged between 24 and 97 years with primary breast cancer diagnosed between 2003 and 2017. Of these patients, 8856 with early breast cancer were eligible for analysis: 8316 (93.9%) were node negative and 540 (6.1%) had lymph node micrometastases.

RESULTS

The median follow-up was 7.2 years, with a confidence interval (CI) of 7.1-7.3 years. Patients with lymph node micrometastases (pN1mi) without adjuvant CHT have reduced 10-year overall survival (OS) and recurrence-free survival (RFS) compared to patients who had axillary lymph node micrometastases and received an adjuvant CHT. However, this effect disappeared after adjustment for age, tumor size and tumor grading. Furthermore, in the group of patients with lymph node micrometastases, the administration of adjuvant CHT did not improve OS or RFS, compared to patients with lymph node micrometastases without adjuvant CHT: hazard ratio for treated patients was 1.51 (95% CI 0.80-2.85, p = 0.208) for OS and 1.12 (95% CI 0.63-1.97, p = 0.705) for RFS.

CONCLUSION

Patients with axillary lymph node micrometastases showed a comparable outcome to node negative patients and their outcome was not significantly improved with CHT. Thus, axillary lymph node micrometastases should not be considered in the treatment decision.

Immunohistochemical detection of axillary lymph node micrometastases in node negative breast cancer patients using cytokeratin and epithelial membrane antigen

Background and Objective:

The study was conducted to detect occult metastases in lymph node negative breast cancer patients using cytokeratin (CK) and epithelial membrane antigen (EMA) immunohistochemistry (IHC) and correlate this with primary tumor size and grade.

Materials and Methods:

A total of 32 cases including 12 prospective and 20 retrospective cases of axillary lymph node negative breast cancer were studied. CK and EMA IHC were performed to detect micrometastases.

Results:

Axillary lymph node metastases were detected in 18.75% of previously node negative cases using CK and EMA IHC. CK was found to be more sensitive for detection of metastases compared to EMA. A highly significant correlation was observed between tumor grade and axillary lymph node metastases detected by CK and EMA. However, no significant correlation was found between tumor size and axillary lymph node metastases detected by IHC.

Conclusion:

In the present study, there was an increase of 18.75% in the occult metastases detection rate using CK and EMA. To conclude, IHC detection of occult metastases should be done using CK in all axillary node negative cases, especially in T1 and T2 stage tumors.

Treatment of sentinel node-positive breast cancer

Sentinel node biopsy has become well accepted as a minimally invasive means of accurately staging the axilla in breast cancer patients. Patients with metastases in the sentinel node(s) have traditionally proceeded to completion of axillary node dissection, whereas patients who are node negative can be spared the morbidity of this procedure. Recently, there has been some debate as to what constitutes node-positive disease and whether patients with metastasis in the sentinel node(s) require completion axillary dissection. This review addresses the controversies regarding the management of sentinel node-positive breast cancer patients.

Sentinel lymph node biopsy for breast cancer: from investigational procedure to standard practice

Sentinel lymph node biopsy, popularized in melanoma, has revolutionized the management of breast cancer. While the morbidity associated with axillary node dissection was once thought to be a requisite risk in order to appropriately stage the axilla, large validation studies have demonstrated that sentinel lymph node biopsy is a minimally invasive technique that can accurately predict nodal status. This technique has become an accepted practice in many centers, but there remain many controversies surrounding the technique itself, the pathologic evaluation of the sentinel node and the optimal management of patients with minimal nodal disease. The historic roots of this technique are discussed, along with the controversial issues surrounding the technique and the clinical trials that are currently ongoing.

Sentinel lymph node micrometastasis in human breast cancer: an update

INTRODUCTION

The advent of sentinel lymph node biopsy (SLNB) and advances in histopathological and molecular analysis techniques have been associated with an increase in micrometastasis (MM) detection rate. However, the clinical significance of sentinel lymph node micrometastasis (SLN MM) continues to be a subject of much debate. In this article we review the literature concerning SLN MM, with particular emphasis on the prognostic significance of SLN MM. The controversies regarding histopathological assessment, clinical relevance and management implications are also discussed.

METHODS

Literature review facilitated by Medline and PubMed databases. Cross referencing of the obtained articles was used to identify other relevant studies.

RESULTS

Published studies have reported divergent and rather conflicting results regarding the clinical significance and implications of axillary lymph node (ALN) MM in general and SLN MM in particular. Some earlier studies demonstrated no associations, however most recent studies have found SLN MM to be an indicator of poorer prognosis and to be associated with non-SLN involvement. The use of adjuvant chemotherapy and/or hormonal manipulation therapy is associated with an improved survival in patients with SLN MM. Complete ALND may be safely omitted provided that adjuvant systemic therapy recommendations are equal to patients with node-positive disease. However, optimal management of SLN MM is yet to conclude. Furthermore, the identification of MM remains largely dependent on the analytical technique employed and the use of immunohistochemistry (IHC) increases the detection rate of SLN MM. Discrepancies in the histopathological interpretation of TNM classification of SLN tumour burden do exist. Published studies were non-randomized and have significant limitations including a small sample size, limited follow-up period, and lack of standardization and reproducibility of pathological examination of the SLN.

CONCLUSION

Patients with SLN MM have a poorer prognosis than those who are SLN negative. Therapeutic recommendations regarding patients with SLN MM should be taken in the context of multidisciplinary team setting and in selected cases of SLN MM, complete ALND may be safely omitted. A better reproducibility of pathological interpretation of the TNM classification is required so that future therapeutic guidelines can be applied without confusion.

The clinical significance of sentinel lymph node micrometastasis in breast cancer

INTRODUCTION

The advent of sentinel lymph node biopsy (SLNB) and improvements in histopathological and molecular analysis have increased the rate at which micrometastases (MM) are identified. However, their significance has been the subject of much debate. In this article we review the literature concerning axillary lymph node (ALN) MM, with particular reference to SLNB. The controversies regarding histopathological assessment, clinical relevance and management implications are discussed.

METHODS

Literature review facilitated by Medline and PubMed databases.

RESULTS

Published studies have reported divergent results regarding the significance and implications of ALN MM in general and sentinel lymph node (SLN) MM in particular. Some studies demonstrate no associations, whilst others have found these to be indicators of poor prognosis, associated with non-SLN involvement, in addition to local and distant failure. Absolute consensus regarding the optimal analytical technique for SLNs has yet to be reached, particularly concerning immunohistochemical (IHC) techniques targeting cytokeratins and the utility of contemporary molecular analysis.

CONCLUSION

SLN MM are likely to represent an incremental detriment to prognosis and increased risk of non-SLN involvement, despite only modest up-staging within current classification systems. In the absence of level-1 guidance concerning the management of women with SLN MM, each case requires discussion with regard to other tumour and patient related factors in the context of the multidisciplinary team. Randomized studies are required to evaluate the prognostic significance and optimal management of each category of tumour burden within the SLN. The identification of MM remains highly dependent on the analytical technique employed and there exists potential for stage migration and impact on management decisions.

Anatomopathological analysis of sentinel and nonsentinel lymph nodes in breast cancer: hematoxylin-eosin versus immunohistochemistry

The authors compare the detection of metastases in sentinel lymph nodes (SLNs) and nonsentinel lymph nodes (NSLNs) using hematoxylin-eosin (HE) staining versus immunohistochemistry (IHC). Thirty-six patients with breast carcinoma undergo exeresis of the primary tumor and of 50 SLNs and 491 NSLNs. Sentinel lymph nodes are sectioned into transverse slices of 2- to 3-mm thickness, and a cytologic smear and a frozen section were obtained from each slice. The slices are completely cut into serial sections at 100-microm intervals. Two consecutive 4-microm-thick sections are then obtained from each level and were prepared for HE staining and IHC. Nonsentinel lymph nodes are evaluated similarly to SLNs. The authors obtain 4076 SLN sections and 32 012 NSLN sections, for a total of 36 088 sections. A comparison of HE staining versus IHC based on the total number of sections shows a sensitivity of 93.8%, a negative predictive value of 98.9%, and an accuracy of 99.1%. The values obtained by HE staining are similar to those obtained by IHC.

Immunocytological Detection of Lymph Node Metastases in Dogs with Malignant Epithelial Tumours

The aim of this study was to compare immunolabelling of cytological specimens with conventional staining in the detection of metastases in lymph nodes from dogs with carcinoma. Cytological touch imprints of 161 lymph nodes from 72 dogs, as well as 50 fine needle aspirates from 23 dogs, with malignant epithelial tumours were included in the study. Immunolabelling was performed with commercially available human antibodies. Touch imprints of all lymph nodes were labelled with broad spectrum anticytokeratins AE1/AE3 and KL1. In addition, lymph node touch imprints from dogs with primary tumours that reacted positively with the specific anticytokeratins CK7 (n=104) and CK20 (n=20) were also labelled with CK7 and CK20. Fine needle aspirates of 50 lymph nodes were examined by immunolabelling with AE1/AE3. "Reference investigations" with a combination of histological and immunohistochemical methods were performed on all lymph nodes. The immunocytological detection of lymph node metastases with the broad spectrum anti-cytokeratin AE1/AE3 in imprint smears resulted in a significant increase in sensitivity (0.99 vs 0.88 [conventional stain]) and in negative predictive value (0.99 vs 0.85) (P<0.01; t-test). Micrometastases in particular were detected more readily. Specificity (0.93 vs 0.88) and positive predictive value (0.95 vs 0.90) did not differ significantly between the two techniques. Immunolabelling with KL1 was associated with lower sensitivity and negative predictive value, indicating lack of cross-reactivity of this antibody with canine epithelial cells. In fine needle aspirates the detection of lymph node metastases, especially micrometastases, was more efficient by mean of immunolabelling with AE1/AE3 than by conventional staining. The study indicated the value of immunocytological labelling for the detection of metastases in cytological specimens of canine lymph node preparations.

Accuracy of pathologic examination in detection of complete response after chemoradiation for esophageal cancer

BACKGROUND

Although a substantial proportion of patients undergoing neoadjuvant chemoradiation for invasive esophageal cancer develop a pathologic complete response (pCR), these patients nonetheless have a poor 5-year survival rate. We hypothesized that routine pathologic examination fails to identify some residual cancer.

METHODS

Patients undergoing esophagectomy for cancer at 2 tertiary care centers were identified. Archived tumor blocks were retrieved for patients with pCR, sectioned at 50-mum intervals and reexamined for residual cancer.

RESULTS

Seventy patients underwent neoadjuvant chemoradiation. Tumor blocks were available for 23 of 26 complete responders. A total of 159 blocks were reexamined. One patient was found to have a possible focus of residual invasive adenocarcinoma versus high-grade dysplasia. The remaining 22 patients had no residual disease.

CONCLUSIONS

A more aggressive examination protocol for postchemoradiation esophagectomy specimens may not result in significant upstaging. Inadequate pathologic examination is likely not a major factor in the suboptimal survival in patients with pCR.

Can axillary dissection be avoided in patients with sentinel lymph node metastasis?

BACKGROUND

Who should undergo a completion dissection following identification of a +sentinel lymph node (SLN) is controversial.

METHODS

The records of 1,133 patients who underwent SLN mapping were reviewed. The association between patient, tumor, and treatment characteristics and the presence of +SLNs and +nonSLNs was analyzed using two-way tables of frequency counts and Pearson chi2 test. Possible predictors of +SLNs and +nonSLNs were analyzed using simple and multiple logistic regression.

RESULTS

One thousand one hundred forty-eight SLN procedures were performed. 367 procedures (32%) yielded +SLNs. For patients with a +SLN, on multiple logistic regression analysis LVSI, increasing numbers of +SLNs, decreasing numbers of negative SLNs, and increasing size of the largest SLN metastasis were statistically significantly associated with increased likelihood of nonSLN involvement. No subgroup was identified that did not have a significant rate of nonSLN involvement on completion axillary dissection, except those who had a large number of negative SLNs (> or =3) and small size of the largest SLN metastasis (<10 mm).

CONCLUSIONS

A definitive answer to the question of who needs a completion axillary dissection awaits the results of ongoing trials. In the interim, our data does not support eliminating dissection for any subgroup of patients with +SLNs.

Axillary sentinel lymph nodes can be falsely positive due to iatrogenic displacement and transport of benign epithelial cells in patients with breast carcinoma

PURPOSE

Immunohistochemical (IHC) staining for cytokeratins (CK) is common practice in evaluating sentinel lymph nodes (SLNs) in patients with breast carcinoma. IHC positivity typically indicates metastasis. SLN procedures are increasingly common in patients with pure intraductal carcinoma (DCIS). Iatrogenic epithelial cell displacement and benign transport of breast epithelial cells into axillary lymph nodes are recently described phenomena. We report 25 cases in which these factors probably resulted in benign epithelial cells in axillary SLNs (ie, false positivity).

METHODS

We reviewed 25 cases of CK-positive SLNs in which the epithelial cells had histologic and IHC characteristics different from their respective patients' underlying breast carcinomas.

RESULTS

In all cases, the cytologic features of the epithelial cells in the SLNs were benign, and 22 matched those of corresponding intraductal papillomas that were involved by or were separate from the DCIS in the original cores or surgical biopsies. Fifteen cases were pure DCIS; most invasive tumors were smaller than 1.0 cm. In six carcinomas (DCIS) showing strong Her-2/neu staining, the corresponding epithelial cells in the SLNs were negative. In 13 tumors that were strongly and uniformly positive for estrogen receptor (ER), the cytokeratin-positive cells in the SLNs were negative for ER. Nineteen cases showed benign epithelial cell displacement at the biopsy site.

CONCLUSION

Epithelial cells in SLNs may result from transport of displaced cells, usually originating in intraductal papillomas. Positive immunohistochemical results in SLNs should be interpreted with extreme caution to avoid automatically concluding that such cells represent metastasis. Sentinel lymph nodes in breast carcinoma can be falsely positive.

Does the Method of Biopsy Affect the Incidence of Sentinel Lymph Node Metastases?

More detailed examination of the sentinel lymph node (SLN) in breast cancer has raised concerns about the clinical significance of micrometastases, specifically isolated tumor cells detected only through immunohistochemical (IHC) staining. It has been suggested that these cells do not carry the same biologic implications as true metastatic foci and may represent artifact. A retrospective institutional review board-approved review was conducted on clinically node-negative breast cancer patients who underwent SLN biopsy (SLNB) between 1997 and 2003. Retrospective analysis of tumor characteristics and the method of the initial diagnostic biopsy were correlated with the presence and nature of metastatic disease in the SLN. Of 537 SLNBs, 123 (23%) were hematoxylin-eosin (H&E) positive. SLN positivity strongly correlated with tumor size (p<0.001) and tumor grade (p=0.025), but not with the method of biopsy (needle versus excisional biopsy). Prior to July 2002, we routinely evaluated H&E-negative SLNs with IHC (n=381). Of the 291 H&E-negative patients, 26 had IHC-only detected micrometastases (9%). The likelihood of detecting IHC-only metastases did not correlate with tumor size or grade, but was significantly higher in patients undergoing excisional biopsy than core needle biopsy. While the method of biopsy has no demonstrable effect on the likelihood of finding metastases in the SLN by routine serial sectioning and H&E staining, it may significantly impact the likelihood of finding micrometastases by IHC. IHC should not be used routinely in the evaluation of the SLN and caution should be used when basing treatment decisions (completion axillary lymph node dissection or adjuvant therapy) on IHC-only detected micrometastases.

The association of cytokeratin-only-positive sentinel lymph nodes and subsequent metastases in breast cancer

INTRODUCTION

The purpose of this study was to better characterize the clinical significance of cytokeratin immunohistochemistry (IHC)-only-positive lymph node metastases among patients with breast cancer.

METHODS

We performed a retrospective review of 334 patients who underwent sentinel lymph node (SLN) biopsy from 1 February 1997 through 31 July 2001. SLN biopsies were evaluated using standard hematoxylin and eosin (H&E) techniques. If H&E was negative, cytokeratin IHC was performed. We then evaluated the incidence of subsequent regional and distant metastatic disease.

RESULTS

Cytokeratin IHC was performed on 183 sentinel node biopsies from 180 patients comprising a total of 427 sentinel lymph nodes. The procedures included lumpectomy and SLN biopsy (n = 83), mastectomy with SLN biopsy (n = 7), lumpectomy with SLN biopsy and completion axillary dissection (n = 80), and modified radical mastectomy with SLN biopsy and completion axillary dissection (n = 13). Cytokeratin IHC was negative in 175 axillary specimens and positive in 8 (4.4%) from 8 different patients. In these eight specimens, deeper sections with subsequent H&E staining additionally identified micrometastasis in four patients. Three of these 8 patients (37.5%) developed distant metastatic disease compared with 1 of the 172 patients (0.6%) with negative cytokeratin IHC (P < .001). Additionally, one of the cytokeratin-positive patients developed regional nodal metastasis compared with none of the 172 cytokeratin-negative patients.

CONCLUSIONS

Cytokeratin IHC provides a clinically relevant adjunct to H&E staining for evaluating sentinel lymph nodes in breast cancer. These data suggest that patients with cytokeratin-positive sentinel nodes are at increased risk for development of regional and distant metastatic disease.

Clinical outcome of patients with lymph node-negative breast carcinoma who have sentinel lymph node micrometastases detected by immunohistochemistry

BACKGROUND

The ideal pathologic assessment of sentinel lymph nodes (SLNs) in patients with breast carcinoma remains controversial. The authors evaluated how detailed assessment of SLNs using immunohistochemistry (IHC) and serial sectioning would affect treatment decisions and outcomes in patients with breast carcinoma who had negative SLNs on standard hematoxylin and eosin staining.

METHODS

The SLNs from patients who were treated between June 1998 and June, 1999 and who had negative lymph node status determined by hematoxylin and eosin staining (n = 84 patients) were evaluated further with serial sectioning and cytokeratin IHC. Patients were offered adjuvant therapy based on primary tumor factors.

RESULTS

The median patient age was 57 years, and the median tumor size was 1.2 cm. At a median follow-up of 40.2 months, 81 patients (96%) were alive with no evidence of disease, 1 patient was alive with disease, 1 patient had died of disease, and 1 patient had died of other causes. Fifteen patients (18%) had micrometastases identified on IHC. Of the total 84 patients, information regarding adjuvant therapy was not available for 5 patients. Of the remaining 79 patients, 10 patients (13%) were not offered adjuvant chemotherapy but had positive SLN status determined by IHC. SLN status based on IHC evaluation did not correlate with age (P = 0.077), tumor size (P = 0.717), grade (P = 0.148), estrogen receptor status (P = 1.000), or lymphovascular invasion (P = 0.274). Furthermore, IHC-detected positive SLN status did not correlate with distant metastasis (P = 0.372) or overall or distant metastasis-free survival (P = 0.543 and P = 0.540, respectively).

CONCLUSIONS

Although the finding of SLN micrometastases by IHC may change management in > 12% of patients, preliminary results suggested that such micrometastases do not affect outcomes significantly.

Molecular Staging of Lymph Nodes from Patients with Esophageal Adenocarcinoma

Purpose: This study was designed to evaluate molecular markers for the detection of micrometastasis in esophageal adenocarcinoma, define algorithms to distinguish positive from benign lymph nodes and to validate these findings in an independent tissue set and in patients with pN0 esophageal adenocarcinoma.

Experimental Design: Potential markers were identified through literature and database searches. All markers were analyzed by quantitative reverse transcription (QRT)-PCR on a limited set of primary tumors and benign lymph nodes. Selected markers were further evaluated on a larger tissue set and classification algorithms were generated for individual markers and combinations. Algorithms were statistically validated internally as well as externally on an independent set of lymph nodes. Selected markers were then used to identify occult disease in lymph nodes from 34 patients with pN0 esophageal adenocarcinoma.

Results: Thirty-nine markers were evaluated, six underwent further analysis and five were analyzed in the external validation study. Two markers provided perfect classification in both the screening and validation sets, although parametric bootstrap analysis estimated 2% to 3% optimism in the observed classification accuracy. Several marker combinations also gave perfect classification in the observed data sets, and estimates of optimism were lower, implying more robust classification than with individual markers alone. Five of thirty-four patients with esophageal adenocarcinoma had positive nodes by multimarker QRT-PCR analysis and disease-free survival was significantly worse in these patients (P = 0.0023).

Conclusions: We have identified novel QRT-PCR markers for the detection of occult lymph node disease in patients with esophageal adenocarcinoma. The objective nature of QRT-PCR results, and the ability to detect occult metastases, make this an attractive alternative to routine pathology.

Sentinel Lymph Node Metastases Detected by Immunohistochemistry Only Do Not Mandate Complete Axillary Lymph Node Dissection in Breast Cancer

BACKGROUND

The significance of breast cancer sentinel lymph node (SLN) metastases detected only by immunohistochemistry staining (IHC) remains poorly understood. This study attempted to quantify the risk of non-SLN metastases.

METHODS

A prospectively collected database of 750 consecutive SLN biopsy procedures in breast cancer patients was reviewed. Medical records were reviewed to supplement the database.

RESULTS

SLNs were identified in 738 (98.4%) of these procedures in 723 patients. Of these, 151 patients (20.5%) had metastases detected by hematoxylin and eosin staining (H&E), and 33 (4.6%) of the 718 with known IHC staining results had metastases detected by IHC only. Twenty-eight (84.8%) of 33 patients with IHC-detected metastases underwent complete axillary lymph node dissection (CALND). The median primary tumor size was 2.0 cm among those undergoing CALND and 0.9 cm among the five patients treated without CALND (P = .10). Two of the 28 patients (7.1%) had additional metastases detected with CALND. These patients had a T3 or T4 invasive lobular primary tumor. Of 24 patients with T1 or T2 primary tumors and IHC-detected metastases who underwent CALND, none had additional metastases detected. Median follow-up was 14.5 months. All patients with IHC-detected SLN metastases were treated with adjuvant systemic therapy. None of the five patients with IHC-detected metastases not undergoing CALND has subsequently manifested clinical axillary disease.

CONCLUSIONS

CALND could have been or was safely omitted in 29 of 29 patients with T1 or T2 primary tumors and metastases detected by IHC. Such patients should be counseled about this low risk before CALND is recommended.

Surgical implications of sentinel node with micrometastatic disease in invasive breast cancer

AIM

To assess the rate of positive axillary clearance (AC) when the sentinel node biopsy (SNB) contains micrometastatic disease in invasive breast cancer and to evaluate the factors that could predict positivity.

PATIENTS AND METHODS

This is a prospective study carried out on 542 successive women undergoing SNB for unifocal T0-T1 N0 invasive breast cancer without previous treatment.

RESULTS

Five hundred and twenty-five sentinel nodes (SN) were found, 142 contained metastases. Fifty-five of the positive SN contained micrometastatic disease only. Of them, 40 patients underwent completion of AC. Six out of 40 patients who had micrometastatic SN had a positive AC, five for micrometastasis between 0.2 and 2 mm (5/34), one for isolated cells in the SN (1/6). None of the studied factors (age, histological tumour size, histological grade, estradiol receptor (ER), histological tumour type, size and method of micrometastasis detection) could significantly predict the status of the AC.

CONCLUSION

As long as the results of ongoing prospective randomised studies are unknown, it remains necessary to perform AC when the SNB contains micrometastatic disease, whatever the size or the detection mode of the metastasis.

Pathological Evaluation of Sentinel Lymph Nodes for Breast Cancer

Recently, sentinel lymph node (SLN) biopsy has been employed to avoid unnecessary lymph node dissection, because SLN negativity for carcinoma metastases may imply an extremely low possibility of non-SLN involvement. Pathological evaluation is essential, but standardized procedures have not yet been determined. Intraoperative consultation, either by frozen section (multiple slices are desirable) or touch imprint cytology, are usually very useful. Their accuracy, however, is variable and depends on the procedures used, but specificity is characteristically 100%, and the missed metastatic focus is always quite minute. After fixation, multiple sections, immunohistochemistry, and their combination will be able to detect small metastatic foci more frequently. The clinical significance of small or submicro- or occult metastases have not yet been clarified, and further investigations are needed. If the SLN is positive for carcinoma metastases, both the procedure for detection and the size of the metastatic focus should be clarified on the pathological reports.

Missed micrometastatic disease in breast cancer

In the era of sentinel lymph node (SLN) biopsy for breast cancer, ultrastaging by enhanced pathologic techniques (serial sections and/or immunohistochemical [IHC] staining) has become logistically feasible for the first time. Retrospective studies suggest that SLN (and bone marrow) micrometastases detected by these methods are prognostically significant, but controversy still surrounds the significance of micrometastases detected only by IHC, and especially of isolated tumor cells. This heterogeneity among micrometastases may confound the interpretation of current prospective clinical trials that aim to determine their significance. A major challenge for future investigations will be to determine if SLN and bone marrow micrometastases represent similar or distinct biologic phenomena, and whether this distinction will have any implications for treatment.

Current controversies in sentinel lymph node biopsy for breast cancer

Despite the widespread use of sentinel lymph node biopsy (SLNBx) in the surgical management of breast cancer patients, several areas remain controversial. The following controversies are reviewed: Learning curves and validation studies. There clearly is a learning curve, and a completion ALND should be done until adequate proficiency is exhibited, both in terms of identification and false-negative rates. Location of injection. Intradermal injection offers superior identification rates compared with peritumoral injection, with comparable false-negative rates. Subareolar injection is as accurate as peritumoral injection. The value of scintigraphy. Routine scintigraphy does not enhance identification or false-negative rates. Mapping agents. Blue dye and radioactive tracer combined to provide a higher identification rate than either used alone.SLNBx in DCIS. In patients with a high risk of microinvasion, such as large tumors, a mass or high-grade DCIS-SLNBx is justified.SLNBx following neoadjuvant chemotherapy. Although there is evidence that SLNBx after neoadjuvant chemotherapy may be accurate, these data should be applied cautiously. Implications of non axillary SLN, especially internal mammary nodes. Data do not support routine resection of internal mammary sentinel lymph nodes outside a clinical trial. Implications of micrometastases in the sentinel lymph node seen only on immunohistochemistry. Since the significance of such metastases is unclear, decisions regarding treatment of these patients should be individualized. The value of completion axillary lymph node dissection. Is being addressed in clinical trials. Until those studies mature, completion ALND should be performed for patients with SLN metastases, but may be abandoned for patients with a negative SLN.

Towards reasonable workload in diagnosis of sentinel lymph nodes: comparison of two frozen section methods

AIMS

To compare two methods of histological assessment with intraoperative diagnosis of sentinel node metastases in breast cancer.

METHODS AND RESULTS

A total of 204 consecutive breast cancer cases with lymphatic mapping, sentinel node biopsy and intraoperative diagnosis were included. The sentinel nodes in the first 102 cases (method A) were bisected and serially sectioned. In the other 102 cases (method B) the nodes were sliced thinly with a razor blade. All 1-1.5 mm thick slices were mounted on prechilled mounting medium on frozen section buttons. Cytological imprints were also made of the attached tissue slices. Postoperative diagnosis of sentinel lymph node metatases was taken as gold standard. Sentinel node metastases were found in 28 (27%) cases in group A and in 42 (40%) cases in group B (P = 0.05). The median size of the sentinel node metastases was 4.3 mm in group A and 3.3 mm in group B (P < 0.05).

CONCLUSION

Method B finds more and smaller metastases and takes less time and effort in the laboratory. When using method A, many small metastases are not detected at all.

The molecular detection of micrometastatic breast cancer

BACKGROUND

The rapid evolution of molecular technology and novel markers provides the opportunity to establish a more effective means to detect micrometastatic breast cancer. Given the controversies concerning application and clinical relevance, this review critically evaluates the current status of these molecular staging technologies.

DATA SOURCES

Breast cancer literature addressing (1). molecular detection methodologies (immunohistochemistry, reverse transcriptase polymerase chain reaction, and microarray analysis); (2). specific tissue applications such as lymph nodes, bone marrow aspirate, and peripheral blood; (3). expert commentary concerning the clinical applications and pitfalls of these technologies; and (4). recent data from our molecular diagnostics laboratory.

CONCLUSIONS

Molecular detection technologies such as reverse transcriptase polymerase chain reaction and microarray analyses are being developed that will likely have future application as cancer diagnostics. Further work is needed to establish assays that are validated by prospective clinical studies. Early identification of clinically relevant disease could lead to new treatment or staging approaches for breast cancer.

Minimal residual disease in breast cancer and gynecological malignancies: phenotype and clinical relevance

In breast cancer, about 35% of patients without any clinical signs of overt distant metastases already have disseminated tumor cells in bone marrow aspirates at the time of primary therapy. A significant prognostic impact of these disseminated tumor cells has been shown by many international studies: patients with tumor cells in their bone marrow have a significantly worse prognosis than those without them. Even in malignancies where the skeletal system is not a preferred location for distant metastasis, such as ovarian cancer, early presence of minimal residual disease (MRD) is correlated with poor patient outcome. Thus, besides analysis of the primary tumor, detection of MRD can be used for assessment of patient prognosis and for prediction or monitoring of response to systemic therapy. Disseminated tumor cells are also the targets for novel tumor biological therapy approaches such as specific antibody-based therapies against target cell-surface antigens such as HER2, Ep-CAM (17-1A), and uPA-R. In breast cancer, a first antibody-based tumor therapy against HER2 (Herceptin) has already been approved for clinical use in recurrent disease. However, patient selection for such tumor biological therapies becomes rather difficult due to phenotype changes, which may manifest themselves as differences between primary lesion and disseminated tumor cells. Therefore, not only identification of disseminated tumor cells but even more so their characterization at the protein and gene levels have become increasingly important. In conclusion, characterization of tumor biological properties of disseminated tumor cells allows identification of patients with breast cancer or gynecological malignancies at risk for relapse who are likely to benefit from systemic treatment and/or novel tumor biological therapy approaches.

Pathological work-up of sentinel lymph nodes in breast cancer. Review of current data to be considered for the formulation of guidelines

Controversies and inconsistencies regarding the pathological work-up of sentinel lymph nodes (SNs) led the European Working Group for Breast Screening Pathology (EWGBSP) to review published data and current evidence that can promote the formulation of European guidelines for the pathological work-up of SNs. After an evaluation of the accuracy of SN biopsy as a staging procedure, the yields of different sectioning methods and the immunohistochemical detection of metastatic cells are reviewed. Currently published data do not allow the significance of micrometastases or isolated tumour cells to be established, but it is suggested that approximately 18% of the cases may be associated with further nodal (non-SN) metastases, i.e. approximately 2% of all patients initially staged by SN biopsy. The methods for the intraoperative and molecular assessment of SNs are also surveyed.

Cytokeratin staining and other sentinel node controversies

Sentinel lymph node (SLN) biopsy for breast cancer staging has been widely accepted because it is more sensitive and less morbid than axillary dissection. Sentinel nodes can be thoroughly scrutinized using a variety of techniques increasing the detection of micrometastases; however, the clinical relevance of micrometastases has been challenged. The available data suggest that the prognostic significance of axillary metastases is related to the size of the metastases, and the best data suggest that outcome for patients with metastases < 0.2 mm is similar to patients with node-negative disease. This would argue against the use of ultrasensitive tests such as reverse transcriptase polymerase chain reaction. Immunohistochemistry upstages 2%-20% of hematoxylin and eosin-negative sentinel nodes, and additional nodal metastases are identified in approximately 10% of completion axillary dissections prompted by an immunohistochemistry (IHC)-positive sentinel node. This would appear to be a good reason to perform IHC and act on the results. Because micrometastases can be artifactual, SLN biopsy in ductal carcinoma in situ can lead to harmful overtreatment and is best performed in the context of clinical trials. Lymphoscintigraphy has allowed the detection of alternate drainage patterns to internal mammary, infraclavicular, and supraclavicular lymph nodes. Although patients are occasionally identified who have metastases to these basins but not the axilla, this information will not impact the decision for chemotherapy in most cases. Internal mammary SLN biopsy may have value in patients with tumors < 1 cm, but requires additional evaluation in clinical trials.

Metastatic infiltrating syringomatous adenoma of the breast

Infiltrating syringomatous adenoma of the breast is classified as a benign, locally invasive neoplasm. To our knowledge, there have been no reported cases of metastasizing syringomatous adenomas. We used sentinel lymph node mapping to identify metastatic cells, leading to a diagnosis of infiltrating syringomatous adenoma of the breast.

Complete sectioning of axillary sentinel nodes in patients with breast cancer. Analysis of two different step sectioning and immunohistochemistry protocols in 246 patients

AIMS

To evaluate two detailed step sectioning protocols for sentinel lymph nodes (SLNs).

METHODS

After vital dye or combined dye and radiocolloid guided biopsy, SLNs were fixed in formalin and embedded in paraffin wax. In protocol A, SLNs from 123 patients were sectioned in steps of 50-100 micro m, whereas in protocol B, SLNs from 123 patients were sectioned at steps of 250 micro m. Epithelial marker immunohistochemistry (IHC) was performed on multiple levels in cases with negative haematoxylin and eosin findings.

RESULTS

In groups A and B, 74 and 47 patients were found to have tumour cells in their axillary SLNs, and 19 (28%) and 18 (19%) patients, respectively, were upstaged as compared with the standard histological assessment. Nodal involvement detected by deeper sections was often micrometastatic or in isolated tumour cells

CONCLUSIONS

Serial sectioning and IHC are recommended for the evaluation of SLNs. The optimal extent of the histopathological work up should be studied further.

Molecular markers in the diagnosis and staging of breast cancer

Considerable advances have been made in understanding the molecular events that accompany the development of breast cancer. Although our knowledge of these genetic alterations has greatly outpaced clinical applications, many new advances are beginning to have an impact on the diagnosis and staging of breast cancer. Clinical evaluation of estrogen and progesterone receptors and HER2/neu status has become routine. The increasing use of these and other molecular markers promises to help refine diagnoses, define disease subsets, and provide more accurate information about the probable biologic outcome of a given tumor. Studies of molecular markers are also likely to lead to the identification and development of new therapeutic targets. I review the molecular markers currently used in the clinical diagnosis and staging of breast cancer, and discuss other potentially useful markers and assays.