Intraoperative cytologic diagnosis of sentinel node metastases in breast cancer

Intra-operative assessment of sentinel lymph nodes for breast cancer surgery: An update

Lymph node (LN) involvement is the strongest prognostic factor in operable breast cancer (BC). Therefore, accurate assessment of LN status is essential for management of BC patients. The introduction of sentinel LN approach reduced the need for extensive axillary surgery to achieve accurate staging. However, positive sentinel LN as determined on postoperative histological examination often leads to a second axillary operation to ensure an accurate staging and that positive non-sentinel LNs are removed. Although preoperative assessment of LN has improved significantly, its accuracy remains insufficient to avoid further axillary surgery and is not sufficient to predict the status of the LN. Therefore, intraoperative evaluation of the sentinel LN to determine the need for completing lymph node dissection in case of metastasis can provide an important approach to guide BC management decision making. This article reviews the techniques available and under development for intraoperative detection of sentinel LN metastasis in BC surgery. The key features of each technique are described in detail, emphasising the benefits offered by label-free optical techniques: minimal sample preparation, high spatial resolution, and immediate on-site implementation. Optical techniques have the potential to provide a cost-effective and accurate intraoperative platform for the assessment of SLN within the operating theatre.

Improved detection of sentinel lymph node metastases allows reliable intraoperative identification of patients with extended axillary lymph node involvement in early breast cancer

An improved procedure that allows accurate detection of negative sentinel lymph node (SLN) and of SLN macrometastases during surgery would be highly desirable in order to protect patients from further surgery and to avoid unnecessary costs. We evaluated the accuracy of an intraoperative procedure that combines touch imprint cytology (TIC) and subsequent frozen section (FS) analysis. 2276 SLNs from 1072 patients with clinical node-negative early breast cancer were evaluated during surgery using TIC. Only cytologically-positive SLN were subsequently analysed with a single FS, preserving cytologically-negative SLN for the final postoperative histological diagnosis. Sensitivity, specificity and the accuracy of this approach were analysed by comparing the results from intra- and postoperative SLN and axillary node evaluation. This intraoperative method displayed 100% specificity for SLN metastases and was significantly more sensitive for prognostically relevant macrometastases (85%) than for micrometastases (10%). Sensitivity was highest for patients with two or more positive LNs (96%) than for those with only one (72%). 98% of the patients with final pN2a-pN3a were already identified during surgery. Patients who received primary axillary lymph node dissection had significantly more frequent metastases in further LNs (44.6%). Sensitivity was highest for patients with luminal-B, HER2+ and triple negative breast cancer and for any subtype if Ki-67 > 40%. TIC and subsequent FS of cytologically-positive SLNs is highly reliable for detection of SLN macrometastases, and allows accurate identification of patients with a high risk of extended axillary involvement during surgery, as well as accurate histological diagnosis of negative SLN.

Prospective Comparison of Intraoperative Touch Imprint Cytology and Frozen Section Histology on Axillary Sentinel Lymph Nodes in Early Breast Cancer Patients

INTRODUCTION

Since the late 1970s, sentinel lymph node biopsy (SLNB) has been used for several solid malignancies to identify lymph node metastases. This procedure is associated with less surgical morbidity than complete lymphadenectomy. Recent evidence suggests that axillary lymphadenectomy is not required for breast sentinel nodes with micrometastases (≤2 mm). Current clinical management of sentinel nodes indicates that only macrometastases (>2 mm) should be detected intraoperatively. In Japan, an intraoperative histopathological frozen section (FS) method is used to identify lymph node metastases, but this method takes more than 30 min and requires complex techniques and expensive equipment. Touch imprint cytology (TIC) is an easier, less expensive, and faster method, but its sensitivity has been shown to be low.

OBJECTIVE

The purpose of this study was to determine if TIC is more useful than FS in identifying macrometastases in sentinel lymph nodes in preoperative node-negative breast cancer operations.

METHODS

A prospective review of 49 consecutive patients with node-negative breast cancer treated with SLNB and intraoperative TIC and FS between November 2017 and June 2019 was performed. TIC samples were stained using Papanicolaou and Diff-Quick stains. Results were compared with routine postoperative paraffin sections.

RESULTS

With TIC, the Papanicolaou stain took a mean of 12 min, and the Diff-Quick stain took a mean of 10 min. Results of both TIC stain methods were the same. In contrast, the FS method took a mean of 80 min (including the transfer of specimens to a different hospital with the necessary equipment). TIC confirmed macrometastases in 5 cases. All macrometastases were diagnosed equally by the 2 techniques. Both the sensitivity and specificity of TIC were 100% for detection of macrometastases.

CONCLUSION

TIC of SLNB for breast cancer is an easy and useful method for the detection of macrometastases of breast sentinel nodes.

Imprint cytology versus frozen section analysis for intraoperative assessment of sentinel lymph node in breast cancer

Introduction

Sentinel lymph node (SLN) biopsy is the gold standard for surgical staging of the axilla in breast cancer (BC). Frozen section (FS) remains the most popular means of intraoperative SLN diagnosis. Imprint cytology (IC) has also been suggested as a less expensive and equally accurate alternative to FS. The aim of our study was to perform a direct comparison between IC and FS on the same SLNs of BC cases operated in a single center by the same surgical team.

Materials and methods

Into this prospective study we enrolled 60 consecutive patients with histologically proven T1–T3 BC and clinically negative axilla. Sentinel nodes were detected using a standard protocol. The SLN(s) was always assessed by IC as well as FS analysis and immunohistochemistry. Nevertheless, all intraoperative decisions were based on FS analysis.

Results

During the study period 60 patients with invasive BC were registered, with 80 SLNs harvested. Mean number of SLN(s) identified for each patient was 1.33. The sensitivity and specificity were 90% and 100%, respectively, for IC, and 80% and 100% for FS. Relevant positive/negative predictive values were 100%/98% for IC and 100%/96.15%, respectively, for FS. Overall accuracy was 98% for IC and 97% for FS. Therefore, statistically significant difference between the two methods in the detection of positive nodes was not elucidated (p=1.000).

Conclusions

IC appeared to be marginally more sensitive than FS in detecting SLN metastatic activity. Overall accuracy was 98.75%. With regard to the primary lesion characteristics, we conclude that initial lesion size and lymphovascular invasion play a pivotal role in metastatic involvement of the SLN with the dimensions of metastasis bearing no correlation with tumor size. Therefore, IC appears to be a sensitive and accurate method for the intraoperative assessment of SLN in BC patients, but further studies are required to confirm this interesting data.

Achieving breast cancer surgery in a single setting with intraoperative frozen section analysis of the sentinel lymph node

BACKGROUND

Current guidelines recommend full axillary lymph node dissection (ALND) whenever the SLN is positive for metastases. In our institute, we aim to complete surgery in a single setting and base the decision for ALND on the intraoperative FS analysis of the SLN. In this study, we evaluate the efficacy this practice in terms of the accuracy of FS analysis, patient recall rate, and additional time required for FS analysis.

MATERIALS AND METHODS

Retrospective review was performed of 586 patients who underwent SLN biopsy at our institution from January 1, 2006 to December 31, 2010. Intraoperative FS analysis was routinely performed in all cases with a preoperative diagnosis of invasive breast cancer and in selected cases of ductal carcinoma in situ according to surgeon preference.

RESULTS

The SLN was positive for metastases in 123 (22.7%) patients; this was identified on FS analysis in 107 patients. FS analysis had a sensitivity of 87.0% and specificity of 100% and resulted in a patient recall rate of 3%. Micrometastasis accounted for most of the false negative FS results. These deposits were mostly detected only on deeper sectioning of the permanent sections of the SLN. An invasive lobular histology and lymphovascular invasion were found to be independent predictors of a false negative FS on multivariate analysis (P < .01). Intraoperative FS did not significantly prolong operating times.

CONCLUSION

Intraoperative FS analysis is an accurate and efficient means of rapid SLN assessment and allows ALND to be completed in a single setting.

Utility of the GeneSearch breast lymph node assay for the rapid evaluation of sentinel lymph nodes in breast cancer

BACKGROUND

The potential for reducing the need for second surgery for axillary lymph node dissection (ALND) has made the intraoperative evaluation of sentinel lymph nodes (SLNs) attractive. The goal of the current study was to evaluate the clinical application of the breast lymph node (BLN) assay, a real-time reverse transcriptase-polymerase chain reaction assay for SLN metastases, by comparing this test with routine pathologic examination.

METHODS

A total of 117 patients with breast cancer underwent breast surgery with SLN biopsy. Each SLN was cut in half along the plane of the longest dimension. Half of each lymph node was examined by the 2 markers of the BLN assay, mammaglobin and cytokeratin 19, and the other half was examined by hematoxylin and eosin staining (H&E) and immunohistochemical staining (IHC) for pancytokeratins.

RESULTS

A total of 204 SLNs were obtained from 117 patients. H&E staining identified metastases in 31 SLNs (15.2%), and IHC staining detected metastases in 6 SLNs; 40 SLNs from 32 patients were found to be positive for metastasis using the BLN assay. The assay results were correlated with the pathologic diagnoses by H&E and IHC staining (P<.001). The sensitivity of the BLN assay compared with pathologic findings classified according to the TNM classification was 95.7% for macrometastases, 60.0% for micrometastases, and 55.6% for isolated tumor cells.

CONCLUSIONS

The 2-marker BLN assay performs in a manner that is comparable to, and analyzes more tissue than, routine pathologic examination. Therefore, clinical intraoperative use of the BLN assay for SLNs may result in a reduction in the need for second surgery for ALND.

Intraoperative assessment of sentinel lymph nodes in breast cancer

Background

Sentinel lymph node biopsy (SLNB) reduces the morbidity of axillary clearance and is the standard of care for patients with clinically node-negative breast cancer. The ability to analyse the sentinel node during surgery enables a decision to be made whether to proceed to full axillary clearance during primary surgery, thus avoiding a second procedure in node-positive patients.

Methods

Current evidence for intraoperative sentinel node analysis following SLNB in breast cancer was reviewed and evaluated, based on articles obtained from a MEDLINE search using the terms ‘sentinel node’, ‘intra-operative’ and ‘breast cancer’.

Results and conclusion

Current methods for evaluating the sentinel node during surgery include cytological and histological techniques. Newer quantitative molecular assays have been the subject of much recent clinical research. Pathological techniques of intraoperative SLNB analysis such as touch imprint cytology and frozen section have a high specificity, but a lower and more variably reported sensitivity. Molecular techniques are potentially able to sample a greater proportion of the sentinel node, and could have higher sensitivity.

Value of frozen section and primary tumor factors in determining sentinel lymph node spread in early breast carcinoma

INTRODUCTION

Sentinel lymph node biopsy (SLNB) is the standard of care to assess the metastasis in breast carcinoma. Accuracy of intraoperative frozen section examination to evaluate SLN in detecting metastasis is important as it determines the further management of axilla. Primary tumor characteristics determining the metastasis to the lymph node will help in predicting the probability of spread and to determine the nature of disease. It also helps in refining selection of patients for SLNB. We evaluated all these criteria on Indian patients for the better management.

MATERIALS AND METHODS

Between January 2005 and April 2009, 114 consecutive patients of all age group of both sex, with cytology or biopsy proven carcinoma breast, clinical stage T1/T2 N0 M0 at Manipal Comprehensive Cancer Center, Manipal Hospital, Bangalore were subjected to SLNB and introperative frozen examination. First 75 cases had complete axillary clearance irrespective of SLNB result and subsequently, positive cases underwent axillary lymph node dissection (ALND). Age of the patient and primary tumor characteristics like size, grade, lymphovascular invasion (LVI), perineural invasion, ER/PR status, Her2-neu status and histological sub-types were evaluated for predicting the SLN metastasis. Feasibility of SLNB in previously treated patient is also evaluated.

RESULTS

The age of the patient ranged from 23 to 87 years and its association with SLN spread is not significant. Frozen section examination had accuracy of 97.37% in determining metastatic sentinel node with sensitivity of 96.15% and specificity of 100% with value P < 0.001. SLN remained significant indicator of the status of rest of axilla with value P < 0.001. Primary tumor characteristics like histological subtypes, grade (P = 0.353), ER/PR status (P = 0.839), Her2-neu status (P =0.296) were not significantly associated with SLN metastasis. Size of the primary tumor (P = 0.002), LVI (P < 0.001), perineural invasion (P = 0.084+) were significant factors determining the SLN metastasis. SLNB evaluation had no false negative values in previously treated breast.

CONCLUSION

SLNB is a valuable method of determining the axillary nodal metastasis. Intraoperative frozen section examination is highly ac-curate in detecting nodal metastasis. Primary tumor characteristics like size, LVI and perineural invasion are significant in predicting SLN metastasis. SLNB remains an important method of predicting axillary metastasis even in previously treated breast carcinomas.

Positive and negative aspects of sentinel lymph node biopsy in breast cancer

The sentinel lymph node (SLN) is the first lymph node to receive lymphatic drainage from a tumor. SLN biopsy has become a mainstay of breast cancer management and is used when the axilla is clinically clear of disease. Staging of the axilla in breast cancer is used to predict prognosis and in planning adjuvant treatment. SLN biopsy is not used where there has been previous axillary or breast radiotherapy or surgery, locally advanced or inflammatory disease and stage IV disease. Controversies remain in several specific clinical situations, including management of the axilla following detection of a positive SLN. There are no sufficiently robust predictive tumor features to prevent completion axillary dissection in these cases. However, there is evidence that immediate axillary surgery for operable, clinically node-negative breast cancer provides no survival benefit and may be unnecessary for many women. SLN biopsy may have a role after neoadjuvant chemotherapy, sparing some women from axillary node dissection. Further work is required to ascertain SLN biopsy sensitivity prior to its routine use in the clinic for multicentric and multifocal disease.

The Utility of Intraoperative Evaluation of Sentinel Lymph Nodes in Breast Cancer

BACKGROUND

In breast cancer treatment, intraoperative sentinel lymph node (SLN) evaluation is used to identify patients who may potentially benefit from immediate completion of axillary lymph node dissection.

METHODS

Prospectively collected breast cancer registry data identified 516 SLN biopsies between January 2003 and December 2005. Intraoperative evaluation (IE) of the SLNs was performed in 479 axillae. Final pathology by hematoxylin and eosin and, for negative nodes, by immunohistochemical stains was compared with the IE result. The effect of IE and final pathology on surgical treatment was examined.

RESULTS

The sensitivities for IE of N0(i+) (n = 39), N1mi (n = 41), and N1a-3a (n = 89) metastases were 0%, 5%, and 63%, respectively. The specificity was 99.7%. IE identified 57 (44%) of SLN-positive (N1mi and N1a-3a) axillae, thus resulting in synchronous axillary lymph node dissection for those patients. Reoperation for false-negative IEs (N1mi or N1a-3a with negative IE) occurred in only 27 axillae (39%).

CONCLUSIONS

IE of SLNs has adequate sensitivity and excellent specificity. In addition to allowing patients to benefit from synchronous surgery, IE helped patients to receive care in concordance with recommended practice guidelines. The false-negative IE of SLNs highlights uncertainty with the clinical significance of axillary nodal staging when only small amounts of metastatic disease are identified in the axilla.

Intraoperative imprint cytology of sentinel lymph nodes in breast cancer: initial experience and lessons learnt in establishing a new practice

AIMS

The initial 18 months experience of performing intraoperative imprint cytology for patients with breast cancer undergoing sentinel lymph node biopsy is described for a single institution. The learning process is compared with published results from institutions with many years of experience in order to assess progress in reaching those ideal results, and the methodology used by these institutions is reviewed.

METHODS

A retrospective review was undertaken of the intraoperative imprint cytology results from 103 patients with breast cancer (yielding a total of 170 lymph nodes) who underwent imprint cytology of their sentinel lymph node. The intraoperative imprint cytology results were compared with the final histopathological results. Details regarding the primary tumour characteristics and metastatic deposit size were recorded.

RESULTS

The sensitivity for imprint cytology was 31.1%, with a specificity of 100% and overall accuracy of 77.8%. The sensitivity for detecting macrometastases (>2 mm diameter) was 61.9% and the sensitivity for micrometastases (<2 mm diameter) and including isolated tumour cells was 4.2%.

CONCLUSIONS

The differences in sensitivity in comparison with many studies in the literature are multifactorial, and include technical aspects, such as the methodology used in the final histopathological and intraoperative evaluation of the sentinel lymph nodes, interpretative difficulties, and much lower case numbers. Furthermore, these numbers represent early experience and methods to improve sensitivity and overall accuracy are detailed in this paper.

Accuracy of intraoperative imprint cytology of sentinel lymph nodes in breast cancer

BACKGROUND

In breast cancer treatment, immediate completion of axillary lymph node dissection (ALND) can be performed if the intraoperative sentinel lymph node (SLN) examination is positive. This study evaluates the accuracy of intraoperative imprint cytology (IC) for detecting SLN metastases.

METHODS

Pathology reports from 385 SLN biopsy examinations were reviewed retrospectively. The SLNs were serially sectioned perpendicular to the long axis and IC was performed intraoperatively. The SLNs then were formalin-fixed for permanent sections. Final pathology was compared with the intraoperative IC results.

RESULTS

The sensitivities for IC detection of N0(i+) (n = 36), N1mi (n = 24), and N1a-3a (n = 65) metastases were 0%, 4%, and 74%, respectively. The specificity was 100%.

CONCLUSIONS

Final pathology identified 89 (23%) patients with N1 or greater disease. IC allowed 49 (55%) of these patients to undergo synchronous completion of ALND. No unnecessary completion ALNDs were performed. The sensitivity of IC decreased with decreasing size of the metastasis.

Frozen section is superior to imprint cytology for the intra-operative assessment of sentinel lymph node metastasis in stage I breast cancer patients

Background

A standard intra-operative procedure for assessing sentinel lymph node metastasis in breast cancer patients has not yet been established.

Patients and methods

One hundred and thirty-eight patients with stage I breast cancer who underwent sentinel node biopsy using both imprint cytology and frozen section were analyzed.

Results

Seventeen of the 138 patients had sentinel node involvement. Results of imprint cytology included nine false negative cases (sensitivity, 47.1%). In contrast, only two cases of false negatives were found on frozen section (sensitivity, 88.2%). There were two false positive cases identified by imprint cytology (specificity, 98.3%). On the other hand, frozen section had 100% specificity.

Conclusion

These findings suggest that frozen section is superior to imprint cytology for the intra-operative determination of sentinel lymph node metastasis in stage I breast cancer patients.

Intraoperative touch imprint cytology for the diagnosis of sentinel lymph node metastases in breast cancer

Background

Intraoperative detection of sentinel lymph node (SLN) metastases enables the surgeon to take an immediate decision to proceed to completion axillary lymph node dissection (ALND). The aim of this study was to determine the accuracy of touch imprint cytology (TIC) for the diagnosis of SLN metastases in sentinel nodes from women with breast cancer.

Methods

Touch imprints from 235 sentinel nodes in 133 women with breast cancer were diagnosed by cytopathology and compared with definitive histopathology results. After a feasibility study, a real-time study was performed with the surgeon proceeding to ALND based on the TIC diagnosis. The clinical opinion of the operating surgeon as to whether the SLN appeared to contain metastases was recorded, as was the time taken for the result to be available.

Results

TIC detected metastases with a sensitivity of 81·1 per cent and a specificity of 100 per cent. False-negative TIC diagnoses were associated with micrometastases and lobular carcinoma. The majority of false-negative diagnoses were due to sampling rather than interpretation errors. Clinical assessment of sentinel nodes had a sensitivity of 64·3 per cent and a specificity of 87·6 per cent.

Conclusion

TIC is feasible and enables the rapid diagnosis of SLN metastases with an acceptable accuracy for clinical use in ductal carcinoma of the breast.

Validation of a breast cancer nomogram for predicting nonsentinel lymph node metastases after a positive sentinel node biopsy

BACKGROUND

Although completion lymph node dissection (CLND) is the standard of care for breast cancer patients with sentinel lymph node (SLN) metastases, the SLN is the only node with tumor in 40% to 60% of cases. To assist with decision-making regarding CLND, investigators at Memorial Sloan-Kettering Cancer Center devised and validated a nomogram for predicting the likelihood of non-SLN metastases. To assess the generalizable use of this nomogram, validation analysis was performed by using an external database.

METHODS

Eight clinicopathologic variables for 200 consecutive breast cancer patients at the University of Texas M. D. Anderson Cancer Center with SLN metastases and CLND were entered into the nomogram. The accuracy of the nomogram to predict non-SLN metastases was assessed by the receiver operating characteristic (ROC) curve and linear regression analysis. The accuracy of the nomogram with touch-imprint cytology (TIC) as a substitute variable for frozen section was also evaluated.

RESULTS

The linear correlation coefficient of the nomogram-predicted probabilities correlated with the observed incidence of non-SLN metastases for all patients (.97). The accuracy of the nomogram as measured by the area under the ROC curve was .71. When applied solely to patients who had TIC assessment of the SLN, the area under the ROC curve was .74.

CONCLUSIONS

This study validated the Memorial Sloan-Kettering Cancer Center breast cancer nomogram by using an external database. TIC seems to be an acceptable substitute for frozen section as a nomogram variable. The nomogram may help predict an individual's risk of non-SLN metastases and assist in patient decision making regarding the benefit of CLND.

Selective Use of Intraoperative Touch Prep Analysis of Sentinel Nodes in Breast Cancer

Imprint cytology (touch prep) is often used for intraoperative examination of sentinel nodes in breast cancer. This allows axillary lymph node dissection (ALND) to be performed immediately for tumor-positive nodes. We evaluated the accuracy of touch prep examination of sentinel nodes and its role in the surgical treatment of breast cancer. We analyzed 169 breast cancer patients who underwent 170 lymphatic mapping procedures with intraoperative touch prep examination. Results from the touch prep were correlated with histopathology and clinical variables. There were 115 true-negative, 35 true-positive, 15 false-negative, and 5 false-positive results. Touch prep had a sensitivity of 70 per cent and specificity of 96 per cent. Positive predictive value, negative predictive value, and diagnostic accuracy were all 88 per cent. The false-negative rate was 30 per cent and correlated with the size of the nodal metastasis and number of involved nodes, but not other patient factors. Touch prep is useful for the evaluation of sentinel nodes in breast cancer, but it has a lower sensitivity than initially reported, particularly in patients with micrometastases. False positive results occur, although they may be reduced after experience with the technique. We recommend that suspicious findings on touch prep should be confirmed by frozen section and that ALND only be performed for histologically documented metastases. We currently perform touch prep only in patients who are at high risk of nodal metastasis or will undergo mastectomy. This improves operative efficiency and limits the impact of false positive and negative results without dramatically increasing the number of patients who require a second surgical procedure.

Meta-analysis of sentinel node imprint cytology in breast cancer

BACKGROUND

Intraoperative diagnosis of breast cancer metastases in axillary sentinel nodes is desirable to avoid a second operation for lymphadenectomy. Imprint or touch-preparation cytology is a popular technique that has high specificity and a wide range of sensitivity.

METHODS

A systematic search of electronic databases was performed. Included articles were assessed for methodological and reporting quality. Random-effects model pooled estimates of sensitivity and specificity were calculated. Single-variable and multivariable meta-regression analyses were performed for predictors of sensitivity.

RESULTS

Thirty-one studies were included; all were of good methodological quality but reporting quality varied. Pooled sensitivity of imprint cytology was 63 (95 per cent confidence interval (c.i.) 57 to 69) per cent and specificity was 99 (95 per cent c.i. 98 to 99) per cent. Pooled sensitivity for macrometastases was 81 per cent and that for micrometastases 22 per cent. Mean or median primary tumour size (P = 0.004), the prevalence of metastases (P = 0.103) and the proportion of micrometastases (P = 0.022) were significant risk factors in single-variable meta-regression analysis. Only the proportion of micrometastases remained significant in multivariable analysis. Frozen sectioning had better sensitivity than imprint cytology in three of four direct comparisons.

CONCLUSION

Imprint cytology is simple and rapid, and has good sensitivity for macrometastases. The significance of poor sensitivity for micrometastases will be determined by trials investigating their natural history.