Axillary staging of breast cancer and the sentinel node

Proteomics of Sentinel Lymph Nodes in Early Breast Cancer for Identification of Thymidylate Synthase as a Potential Biomarker to Flag Metastasis: A Preliminary Study

Introduction

Breast cancer is the second most common cancer in women across the world. Some of the patients who present in the early stage of disease are affected by metastasis to the axillary group of lymph nodes. The first among this group that is affected is called as sentinel lymph node, and its diagnosis is crucial for the staging of cancer thereby dictating the type of surgical therapy. Therefore, the sentinel lymph node status provides the most relevant information to the surgeon and patient prognosis. The expanded utilization of breast conservation surgery has declined the morbidity associated with mastectomy and axillary lymph node surgery. Recent interest is, therefore, centered on techniques that allow accurate assessment of the sentinel lymph node metastasis. A current procedure such as sentinel lymph node biopsy (SLNB) that is used to assess axillary lymph node metastasis is neither specific nor sensitive, and besides, it is time-consuming.

Objective

To compare the protein profiles between metastatic and non-metastatic lymph nodes to identify a biomarker that can flag lymph node metastasis.

Materials and Methods

Women with early breast cancer were screened using mammography imaging and recruited to the study. Surgical resection was done to remove the breast tissue, and sentinel lymph node was identified using fluorescein and methylene blue tracer. Lymph node was sliced, and one set was sent for histopathology, which was considered the gold standard to assess the metastatic status of the lymph node. One set of slices was taken for proteomic experiments. Proteins were labelled with fluorescent cyanine tags and were subjected to difference gel electrophoresis experiment. Differentially expressed spots that had at least a twofold relative ratio and consistent pattern across three sets of biological replicate experiments were marked. Gel spots were trypsin digested and identified on mass spectrometry machine. Validation study was done by Western blot experiment on the same set of samples.

Results

Thymidylate synthase has a twofold higher expression in the metastatic sentinel lymph nodes as compared to non-metastatic lymph nodes in early breast cancer patients.

Conclusion

Differential in gel expression proteomics is an ideal platform for the identification of potential protein biomarker candidates that can differentiate metastatic from non-metastatic lymph nodes in early breast cancer. The identification of thymidylate synthase offers a scope to develop an on-table diagnostic kit to assess the status of sentinel lymph nodes during mastectomy procedure to guide surgical management of axillary lymph nodes in early breast cancer.

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Comparison of Nodal Target Volume Definition in Breast Cancer Radiation Therapy According to RTOG Versus ESTRO Atlases: A Practical Review From the TransAtlantic Radiation Oncology Network (TRONE)

Regional nodal irradiation has gained interest in recent years with the publication of several important randomized trials and the availability of more conformal techniques. Target volume delineation represents a critical step in the radiation planning process. Adequate coverage of the microscopic tumor spread to regional lymph nodes must be weighed against exposure of critical structures such as the heart and lungs. Among available guidelines for delineating the clinical target volume for the breast/chest wall and regional nodes, the Radiation Therapy Oncology Group and European Society for Radiotherapy and Oncology guidelines are the most widely used internationally. These guidelines have been formulated based on anatomic boundaries of areas historically covered in 2-dimensional field-based radiation therapy but have not been validated by patterns-of-failure studies. In recent years, an important body of data has emerged from mapping studies documenting patterns of local and regional recurrence. We aim to review, discuss, and compare contouring guidelines for breast cancer radiation therapy in the context of contemporary data on locoregional relapse to improve their implementation in modern practice.

How Pre-operative Sentinel Lymph Node Contrast-Enhanced Ultrasound Helps Intra-operative Sentinel Lymph Node Biopsy in Breast Cancer: Initial Experience

We aimed to evaluate the value of sentinel lymph node contrast-enhanced ultrasound (SLN-CEUS) and surface tracing for the biopsy of intra-operative sentinel lymph nodes (SLNs). Between June 2015 and December 2017, a total of 453 patients with early invasive breast cancer were recruited. Patients received an intradermal injection of microbubble contrast agent around the areola on the day before surgery. The locations and sizes of lymphatic channels (LCs) and SLNs were marked on the body surface using gentian violet. Then, injection of double blue dye was performed half an hour before surgery. We compared the pathway of LCs and the location of SLNs obtained from SLN-CEUS and blue dye during surgery. Among the 453 patients, the mean numbers of LCs and SLNs detected by SLN-CEUS were 1.42 and 1.72, respectively, and the coincidence rate was 98.2% compared with blue dye during surgery. The median distance from the SLN to skin measured by pre-operative CEUS and blue dye was 1.95 ± 0.69 and 2.03 ± 0.87 cm (p = 0.35). There were three SLN enhancement in our research, including homogeneous enhancement, inhomogeneous enhancement and no enhancement, with the sensitivity, specificity, positive predictive value and negative predictive value of SLN-CEUS for the diagnosis of SLNs being 96.82%, 91.91%, 87.54% and 98.01%, respectively. SLN-CEUS with skin marking can identify the pathway of LCs and the location of the SLN before surgery, measure the distance from the SLN to skin and determine if the SLN is metastatic. SLN-CEUS can be used as an effective complement to the blue dye method.

Real time analysis of brain tissue by direct combination of ultrasonic surgical aspiration and sonic spray mass spectrometry

Direct combination of cavitron ultrasonic surgical aspirator (CUSA) and sonic spray ionization mass spectrometry is presented. A commercially available ultrasonic surgical device was coupled to a Venturi easy ambient sonic-spray ionization (V-EASI) source by directly introducing liquified tissue debris into the Venturi air jet pump. The Venturi air jet pump was found to efficiently nebulize the suspended tissue material for gas phase ion production. The ionization mechanism involving solely pneumatic spraying was associated with that of sonic spray ionization. Positive and negative ionization spectra were obtained from brain and liver samples reflecting the primary application areas of the surgical device. Mass spectra were found to feature predominantly complex lipid-type constituents of tissues in both ion polarity modes. Multiply charged peptide anions were also detected. The influence of instrumental settings was characterized in detail. Venturi pump geometry and flow parameters were found to be critically important in ionization efficiency. Standard solutions of phospholipids and peptides were analyzed in order to test the dynamic range, sensitivity, and suppression effects. The spectra of the intact tissue specimens were found to be highly specific to the histological tissue type. The principal component analysis (PCA) and linear discriminant analysis (LDA) based data analysis method was developed for real-time tissue identification in a surgical environment. The method has been successfully tested on post-mortem and ex vivo human samples including astrocytomas, meningeomas, metastatic brain tumors, and healthy brain tissue.

Prognostic value of regional lymph node status in canine mammary carcinomas

In this study, we have determined the prognostic value of the presence of the micrometastases and metastases greater than 2 mm in the regional lymph nodes for bitches with mammary carcinomas. The study involved 51 dogs diagnosed with a single malignant epithelial tumour in the 4th or 5th mammary gland. All animals underwent regional mastectomy; the 4th and 5th mammary glands were removed together with the inguinal lymph node. The lymph nodes were examined immunohistochemically using the anti-cytokeratin antibody, clone AE1/AE3. The bitches were followed up every 6 months for 2 years after surgery to determine the disease-free survival (DFS) and overall survival (OS). The Kaplan-Meier analysis showed a statistically significant difference in DFS and OS only between the group of bitches without metastases and the group with lymph node metastases greater than 2 mm. No significant differences between these two groups versus bitches with lymph node micrometastases were found.

Prognostic value of lymph node micrometastases in breast cancer: a multicenter cohort study

Background

To evaluate the prognostic meaning of lymph node micrometastases in breast cancer patients.

Methods

Between January 2000 and January 2003, 1411 patients with a cT_1-2N₀ invasive breast carcinoma underwent surgery in 7 hospitals in the Netherlands. Sentinel lymph node biopsy was done in all patients. Based on lymph node status, patients were divided into 4 groups: _pN₀ (n = 922), _pN_1micro (n = 103), _pN_1a (n = 285), and _pN_≥1b (n = 101). Median follow-up was 6.4 years.

Results

At the end of follow-up, 1121 women were still alive (79.4%), 184 had died (13.0%), and 106 were lost to follow-up (7.5%). Breast cancer recurred in 244 patients: distant metastasis (n = 165), locoregional relapse (n = 83), and contralateral breast cancer (n = 44). Following adjustment for possible confounding characteristics and for adjuvant systemic treatment, overall survival (OS) remained comparable for _pN₀ and _pN_1micro and was significantly worse for _pN_1a and _pN_≥1b (hazard ratio [HR] 1.18; 95% confidence interval [95% CI] 0.58–2.39, HR 2.47; 95% CI 1.69–3.63, HR 4.36; 95% CI 2.70–7.04, respectively). Disease-free survival (DFS) was similar too in the _pN₀ and _pN_1micro group, and worse for _pN_1a and _pN_≥1b (HR 0.96; 95% CI 0.56–1.67 vs HR 1.64; 95% CI 1.19–2.27, HR 2.95; CI 1.98–4.42). The distant metastases rate also did not differ significantly between the _pN₀ and _pN_1micro group and was worse for _pN_1a and _pN_≥1b (HR 1.22; 95% CI 0.60–2.49, HR 2.26; 95% CI 1.49–3.40, HR 3.49; CI 2.12–5.77).

Conclusions

In breast cancer patients survival is not affected by the presence of micrometastatic lymph node involvement.

Electronic supplementary material

The online version of this article (doi:10.1245/s10434-010-1451-z) contains supplementary material, which is available to authorized users.

Ultrastaging of lymph node in uterine cancers

Background

Lymph node status is an important prognostic factor and a criterion for adjuvant therapy in uterine cancers. While detection of micrometastases by ultrastaging techniques is correlated to prognosis in several other cancers, this remains a matter of debate for uterine cancers. The objective of this review on sentinel nodes (SN) in uterine cancers was to determine the contribution of ultrastaging to detect micrometastases.

Methods

Review of the English literature on SN procedure in cervical and endometrial cancers and histological techniques including hematoxylin and eosin (H&E) staining, serial sectioning, immunohistochemistry (IHC) and molecular techniques to detect micrometastases.

Results

In both cervical and endometrial cancers, H&E and IHC appeared insufficient to detect micrometastases. In cervical cancer, using H&E, serial sectioning and IHC, the rate of macrometastases varied between 7.1% and 36.3% with a mean value of 25.8%. The percentage of women with micrometastases ranged from 0% and 47.4% with a mean value of 28.3%. In endometrial cancer, the rate of macrometastases varied from 0% to 22%. Using H&E, serial sectioning and IHC, the rate of micrometastases varied from 0% to 15% with a mean value of 5.8%. In both cervical and endometrial cancers, data on the contribution of molecular techniques to detect micrometastases are insufficient to clarify their role in SN ultrastaging.

Conclusion

In uterine cancers, H&E, serial sectioning and IHC appears the best histological combined technique to detect micrometastases. Although accumulating data have proved the relation between the risk of recurrence and the presence of micrometastases, their clinical implications on indications for adjuvant therapy has to be clarified.

Comparability of different pathologic protocols in sentinel lymph node evaluation: an analysis of two step-sectioning methods for the same patients with breast cancer

CONTEXT

The pathologic protocol for sentinel lymph node evaluation has yet to be standardized. Results from previous studies are troublesome to compare because they have been conducted on different sets of subjects with cancer.

OBJECTIVE

To compare the detection of sentinel lymph node metastases by using step-sectioning methods at 20-microm and 150-microm intervals for the same patient with primary breast cancer.

DESIGN

A total of 186, initially tumor-negative sentinel lymph nodes from a group of 80 patients with breast cancer were included. For all nodes, each paraffin block was cut serially to produce a total of 10 levels: 5 consecutive levels of sections for each of the 20-microm and 150-microm intervals. The nodal findings obtained at these intervals on hematoxylin-eosin and cytokeratin slides were compared by using the McNemar test.

RESULTS

The overall detection rate for sentinel lymph node metastasis at intervals of 20 microm and 150 microm was 27.5% (22/80) and 20% (16/80), respectively. The overall agreement between the 20-microm and 150-microm sections was 82.5%. No macrometastasis was missed by either method. At the 20-microm interval, 2 cases of micrometastasis were missed, while 10 cases of isolated tumor cells were missed at the 150-microm interval. However, no statistical difference was observed for the final sentinel lymph node results with either method. (McNemar test, P = .18 for case-based results and P = .052 for nodal-based results).

CONCLUSIONS

The 20-microm and 150-microm interval step-sectioning methods produce comparable results for detection of metastatic deposits in sentinel lymph nodes.

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.

Promoter hypermethylation for molecular nodal staging in non-small cell lung cancer

CONTEXT

Even among cases of non-small cell lung cancer (NSCLC) in the most favorable stage (IA), the disease-specific mortality is 25% or greater. One plausible explanation implicates the simplistic standard pathologic procedures used to designate lymph node involvement. A more sensitive assessment of the nodal status may improve staging.

OBJECTIVE

To determine the prognostic impact of detecting an abnormal molecular event (promoter hypermethylation in a set of relevant genes) in histologically uninvolved lymph nodes in resected NSCLC.

DESIGN

In this retrospective analysis of archived material, we examined DNA extracted from lymph nodes of stage I NSCLC (n = 180). Patients underwent surgery between 1991 and 1995 in a single institution. Methylation-specific polymerase chain reaction was used to detect promoter hypermethylation in a panel of 8 genes. Survival data were extracted from the computerized database at the Tumor Registry.

RESULTS

Evidence of promoter hypermethylation in at least 1 gene was detected in 67% of these N0 nodes. The most commonly hypermethylated gene was E-cadherin (53%). The hypermethylation frequency for the remaining genes were as follows: APC, 5%; p16, 9%; MGMT, 11%; hMLH1, 15%; RASSF1A, 4%; DAP kinase, 9%; and ATM, 19%. The presence of promoter hypermethylation in 2 or more genes did not influence the overall, median, or 5-year survival rates.

CONCLUSIONS

Identifying promoter hypermethylation (in our panel) in N0 lymph nodes in stage I NSCLC cannot be recommended for clinical decision making. Molecular abnormalities, including those found in cancer by qualitative methylation-specific polymerase chain reaction, are not synonymous with established, histologically detectable metastasis.

What is a positive sentinel lymph node in a breast cancer patient? A practical approach

Sentinel lymph node (SN) biopsy has become increasingly used for the staging of breast carcinoma, resulting in the upstaging of this disease, and this has led to concerns with regard to what should be considered a positive SN. Factors influencing the positive staging of an SN include metastasis size, the method used for metastasis detection, the definition of metastasis and the individual pathologist. Until evidence to the contrary emerges, an SN should be considered positive if metastases (nodal involvement >0.2mm in the largest dimension) are detected in it by histology. A target size should be identified, and SNs, as the most likely sites of nodal metastases, should be searched systematically to find (nearly) all of the targeted metastases. The European guidelines for SN assessment have set two such target sizes: as a minimum, all metastases >2mm should be identified, and optimally all micrometastases should also be sought.

Histopathologic Examination of the Sentinel Lymph Nodes

Sentinel lymph nodes (SLNs) are the most likely site of regional metastasis. Their step sectioning and cytokeratin immunohistochemistry (IHC) result in the upstaging of breast cancer. The heterogeneity of histologic methods is partially responsible for differences in nodal upstaging of the disease in different reports. Intraoperative assessment might be done by both frozen sections and imprint cytology; both methods have advantages and disadvantages. Several guidelines relating to the histopathology of sentinel nodes, including the recent European Working Group for Breast Screening Pathology guidelines, are briefly summarized. These latter advocate multilevel assessment of grossly or intraoperatively negative sentinel nodes with levels separated by a maximum of 1 mm and allow IHC in their assessment, although this latter method is not mandatory. Both methods of intraoperative evaluation are allowable. There are also minimum requirements for the reports on sentinel node histology. For example, the reports should include the extent of nodal involvement, the method used for their identification, and preferably the method used for investigating the sentinel nodes, even if the results are negative. These guidelines are intended to form the basis for national guidelines in European countries.

Evaluation of sentinel lymph nodes in breast cancer

Sentinel lymph node biopsy is an accurate method for the detection of axillary metastases in cases of breast carcinoma and is of value as a replacement for axillary dissection. There is variation, however, in the methods and protocols used for the histopathological evaluation of sentinel lymph nodes, standardisation of which will be required if results of sentinel lymph node analysis are to be used to stratify patients into prognostic groups. The significance of micrometastases, isolated tumour cells (ITCs) and the value of immunohistochemistry are also matters for further definition. In this Expert Opinion we present reviews from two authors, providing American and European perspectives on the approach to sentinel lymph node evaluation.

Comparison of three different staining techniques for intraoperative assessment of nodal metastasis in breast cancer

Imprint cytology has increasingly been used for intraoperative assessment of nodal status in breast cancer. We carried out this study to compare the efficacy of Jenner Giemsa (JG), hematoxylin-eosin (H&E), and Papanicolaou (Pap) stains for intraoperative lymph node imprint cytology (IIC) in breast cancer. One hundred and seven cases of stage I-III breast cancer were studied. Overall, IIC was accurate in 95.3% cases and had a sensitivity and specificity of 98.5% and 90.0%, respectively. The accuracy of JG (95.3%) was better than that of H&E (90.6%) and Pap (94.0%), although the differences were not statistically significant. Problems encountered included cell loss and drying artifacts with H&E and Pap and the inability to distinguish between tumor cells and histiocytes confidently in tight cellular clusters that were occasionally seen. Opinion was possible in all JG cases, but not in five and four cases by H&E and Pap, respectively. Although the choice of the stain would vary depending on the experience of the pathologist, our work suggests that JG, because of fewer technical problems and superior accuracy, may be preferable over H&E and Pap.

Modeling the effect of tumor size in early breast cancer

SUMMARY BACKGROUND DATA

The purpose of this study was to determine the type of relationship between tumor size and mortality in early breast carcinoma.

METHODS

The data was abstracted from 83,686 cases registered in the Surveillance, Epidemiology, and End Results Program of women diagnosed with primary breast carcinoma between 1988 and 1997 presenting with a T1-T2 lesion and no metastasis in whom axillary node dissection was performed: 58,070 women were node-negative (N0) and 25,616 were node-positive (N+). End point was death from any cause. Tumor size was modeled as a continuous variable by proportional hazards using a generalized additive models procedure.

RESULTS

Functionally, a Gompertzian expression exp(-exp(-(size-15)/10)) provided a good fit to the effect of tumor size (in millimeters) on mortality, irrespective of nodal status. Quantitatively, for tumor size between 3 and 50 mm, the increase of crude cumulative death rate (number of observed deaths divided by the number of patients at risk) increased with size from 10% to 25% for N0 and from 20% to 40% for N+.

CONCLUSIONS

The functional relationship of tumor size with mortality is concordant with current knowledge of tumor growth. However, its qualitative and quantitative independence of nodal status is in contradiction with the prevailing concept of sequential disease progression from primary tumor to regional nodes. This argues against the perception that nodal metastases are caused by the primary tumor.

Intraoperative frozen section examination of axillary sentinel lymph nodes in breast cancer

The study presents the results from intraoperative frozen section assessment of axillary sentinel lymph nodes (SLNs) in breast cancer. Routine histological frozen sections from one level were used, two sections stained with haematoxylin and eosin. Immunohistochemistry for cytokeratins was applied to the permanent SLN paraffin sections only. Axillary dissection was performed on all SLN-positive cases regardless of the size of the metastatic deposits. With a detection rate of 83%, 272 patients entered the study over a period of 46 months. A total of 61 cases were SLN positive by frozen section analysis. The paraffin sections gave an additional 23 SLN-positive cases. The false-negative rate for frozen sections was then 27% (23/84). Micrometastases were found in 28 of 84 cases, and macrometastases in 56. The false-negative rate of frozen sections for micrometastases was 71% (20/28), and for macrometastases 5% (3/56). A total of 73% (61/84) of the patients underwent axillary surgery as a one-step procedure.

A concept for the clinical implementation of sentinel lymph node biopsy in patients with breast carcinoma with special regard to quality assurance

The development of standardized and reproducible clinical pathways is an important precondition for quality assurance in medicine, especially if a new method has not yet been ultimately validated. Sentinel lymph node biopsy (SLNB) is a widely accepted new surgical procedure in the treatment of early breast carcinoma. However, numerous steps of the method and details of the technique are not standardized and, thus, hamper quality assurance for SLNB. The German Society of Senology appointed an interdisciplinary consensus committee to work out guidelines for the standardized performance and quality-assured implementation of SLNB on a nationwide, homogeneous standard. The committee consisted of surgeons, gynecologists, radiooncologists, nuclear physicians, oncologists, and pathologists. Relevant questions related to patient selection, lymphatic mapping, surgery, histopathologic work-up, further local and systemic treatment decisions, patient information, training, and follow-up were evaluated with respect to clinical evidence, objectivity, and reproducibility. Clinical pathways were developed on the basis of this analysis. Requirements to the performing institutions and surgeons were defined.

Use and Limitations of a Nomogram Predicting the Likelihood of Non-Sentinel Node Involvement after a Positive Sentinel Node Biopsy in Breast Cancer Patients

After a positive sentinel lymph node (SLN) biopsy, some patients may be considered to have a very low risk of non-SLN involvement and could be candidates for axillary sparing. The aim of this study was to validate the nomogram created at the Memorial Sloan-Kettering Cancer Center (MSKCC) for the prediction of non-SLN involvement in an independent set of 140 patients with both positive SLNs and axillary dissection. The predicted proportions of positive non-SLNs were compared with the observed percentages of non-SLN metastasis. Although the SLN metastasis size and tumor size did influence the risk of non-SLN involvement, the correlation between the predicted and observed proportions was weaker for our patients (R: 0.84) than for the patients assessed at the MSKCC (R: 0.97). Differences were noted in the intraoperative assessment and in the final histology of the SLNs (imprints vs frozen sections and more detailed vs less detailed, respectively), and these could partly explain the lower level of the correlation. The nomogram could not be validated and was found to be of only limited use for the prediction of non-SLN involvement in patients operated on under similar, though not fully identical conditions. We therefore warn against the unvalidated use of this prediction tool.

Meta-analysis of non-sentinel node metastases associated with micrometastatic sentinel nodes in breast cancer

BACKGROUND

The need for further axillary treatment in patients with breast cancer with low-volume sentinel node (SN) involvement (micrometastases or smaller) is controversial.

METHODS

Twenty-five studies reporting on non-SN involvement associated with low-volume SN involvement were identified using Medline and a meta-analysis was performed.

RESULTS

The weighted mean estimate for the incidence of non-SN metastases after low-volume SN involvement is around 20 per cent, whereas this incidence is around 9 per cent if the SN involvement is detected by immunohistochemistry (IHC) alone. Subset analyses suggest that studies with axillary dissection after any type of SN involvement result in somewhat higher estimates than studies allowing omission of axillary clearance, as do studies with more detailed histological evaluation of the SN compared with those with a less intensive histological protocol. Higher-quality papers yield lower pooled estimates than lower-quality papers.

CONCLUSION

The risk of non-SN metastasis with a low-volume metastasis in the SN is around 10-15 per cent, depending on the method of detection of SN involvement. This should be taken into account when assessing the risk of omission of axillary dissection after a positive SN biopsy yielding micrometastatic or immunohistochemically positive SNs.

Discrepancies in current practice of pathological evaluation of sentinel lymph nodes in breast cancer. Results of a questionnaire based survey by the European Working Group for Breast Screening Pathology

AIMS

To evaluate aspects of the current practice of sentinel lymph node (SLN) pathology in breast cancer via a questionnaire based survey, to recognise major issues that the European guidelines for mammography screening should address in the next revision.

METHODS

A questionnaire was circulated by mail or electronically by the authors in their respective countries. Replies from pathology units dealing with SLN specimens were evaluated further.

RESULTS

Of the 382 respondents, 240 European pathology units were dealing with SLN specimens. Sixty per cent of these units carried out intraoperative assessment, most commonly consisting of frozen sections. Most units slice larger SLNs into pieces and only 12% assess these slices on a single haematoxylin and eosin (HE) stained slide. Seventy one per cent of the units routinely use immunohistochemistry in all cases negative by HE. The terms micrometastasis, submicrometastasis, and isolated tumour cells (ITCs) are used in 93%, 22%, and 71% of units, respectively, but have a rather heterogeneous interpretation. Molecular SLN staging was reported by only 10 units (4%). Most institutions have their own guidelines for SLN processing, but some countries also have well recognised national guidelines.

CONCLUSIONS

Pathological examination of SLNs throughout Europe varies considerably and is not standardised. The European guidelines should focus on standardising examination. They should recommend techniques that identify metastases > 2 mm as a minimum standard. Uniform reporting of additional findings may also be important, because micrometastases and ITCs may in the future be shown to have clinical relevance.

Breast-conserving surgery with or without radiotherapy: pooled-analysis for risks of ipsilateral breast tumor recurrence and mortality

BACKGROUND

The objective of the study was to investigate whether radiotherapy or its omission after breast-conserving surgery has measurable consequences on local tumor growth and patient survival.

METHODS

We conducted a pooled analysis of published randomized clinical trials that compared radiotherapy versus no radiotherapy after breast-conserving surgery. The outcomes studied were ipsilateral breast tumor recurrence and patient death from any cause. The pooled relative risks (RRs) were estimated with a random-effects model. Heterogeneity was assessed using the Cochran Q test.

RESULTS

A search of the literature identified 15 trials with a pooled total of 9422 patients available for analysis. The relative risk of ipsilateral breast tumor recurrence after breast-conserving surgery, comparing patients treated with no radiotherapy or radiotherapy, was 3.00 (95% confidence interval [CI] = 2.65 to 3.40). Mortality data were available for 13 trials with a pooled total of 8206 patients. The relative risk of mortality was 1.086 (95% CI = 1.003 to 1.175), corresponding to an estimated 8.6% (95% CI = 0.3% to 17.5%) relative excess mortality if radiotherapy was omitted.

CONCLUSION

Omission of radiotherapy is associated with a large increase in risk of ipsilateral breast tumor recurrence and with a small increase in the risk of patient mortality.

Sentinel node dissection as definitive treatment for node negative breast cancer patients

AIMS

Negative sentinel node may predict tumour-free axillary nodes in breast cancer. We report the performance of sentinel node dissection at our Institution.

METHODS

We analysed data from 212 consecutive women with primary invasive breast tumours less than 3 cm in diameter and no axillary lymphadenopathy who underwent radioguided sentinel node dissection by means of 99mTc-colloidal albumin between 1999 and 2002. Completion axillary node dissection was performed if sentinel nodes contained metastases or if no sentinel nodes were identified.

RESULTS

Sentinel nodes were identified in 207/212 of the patients. Fifty-seven patients had tumour-positive sentinel nodes. Only tumour diameter showed significant association with sentinel node status (p<0.000). Per-operative histologic evaluation had a sensitivity of 67.3% and a negative predictive value of 90.4%. No subset of sentinel node positive patients was identified for whom axillary node dissection could be safely avoided. No recurrences were detected at a median follow-up of 15 months.

CONCLUSION

Radioguided sentinel node dissection offers a reliable way to assess nodal status in most breast cancer patients. In our experience, both preoperative lymphoscintigraphy and intraoperative histologic evaluation add useful information to the procedure.

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.

Effect of Increasing the Surface Sampled by Imprint Cytology on the Intraoperative Assessment of Axillary Sentinel Lymph Nodes in Breast Cancer Patients

As axillary sentinel nodes predict the nodal status and may allow dissection of the axilla on a selective basis we assessed the effects of increasing the surface sampled during intraoperative imprint cytology. Sentinel nodes from 110 patients identified with Patent blue and/or the high radioactivity due to the uptake of 99m-Tc-labeled colloidal albumin were analyzed via hematoxylin and eosin-stained touch preparations. Imprint cytology was performed either on bisected nodes (Protocol One; n = 55) or on sentinel nodes sliced into multiple pieces at 2- to 3-mm intervals (Protocol Two; n = 55). The sentinel nodes were submitted in toto to permanent step sectioning and immunostaining for cytokeratins. There were equal numbers of patients with involved nodes in the two groups assessed. With Protocols One and Two the imprints had sensitivities of 52 and 61 per cent, negative predictive values of 74 and 78 per cent, and false negative rates of 47 and 39 per cent, respectively. No macrometastasis missed by Protocol Two was absent from the surface sampled. These data suggest that increasing the surface sampled improves the proportion of involved sentinel nodes detected intraoperatively by imprint cytology, but a number of metastatic nodes still remain undetected by this method. The sampling of multiple surfaces is encouraged for a more accurate intraoperative assessment.

Nodal staging of colorectal carcinomas and sentinel nodes

This review surveys the staging systems used for the classification of colorectal carcinomas, including the TNM system, and focuses on the assessment of the nodal stage of the disease. It reviews the quantitative requirements for a regional metastatic work up, and some qualitative features of lymph nodes that may help in the selection of positive and negative lymph nodes. Identification of the sentinel lymph nodes (those lymph nodes that have direct drainage from the primary tumour site) is one such qualitative feature that is claimed to allow the upstaging of colorectal carcinomas via an oriented, enhanced pathological work up. Current evidence in favour of a change in the requisite of assessing as may lymph nodes as is possible, and concentrating the efforts on only a selected number of lymph nodes, is weak.

Histologic localization of sentinel lymph node metastases in breast cancer

Data from a recent study support the hypothesis that axillary lymph node metastases frequently localize near the inflow junction of the afferent lymphatic vessel. Our goal was to evaluate the microscopic location of axillary sentinel lymph node metastases in a prospective study of breast cancer patients. A total of 305 axillary sentinel lymph nodes from 213 breast cancer patients undergoing surgery at our institution were evaluated. Preoperative lymphoscintigraphy using technetium-labeled sulfur colloid and intraoperative isosulfan blue dye injection were used for identifying the sentinel lymph node. Intraoperatively, the surgeon placed a suture either at the point of entry of isosulfan blue dye or at the area with the highest radioactive counts, and this area was inked at the grossing bench before processing. Metastases were identified in 55 of the 305 lymph nodes examined. Thirty-four nodes contained metastases in both the inked half and the opposite half. Metastatic tumor was identified in the inked half alone in 18 lymph nodes. Only three nodes contained metastatic tumor in the opposite half with no tumor in the inked half (p <0.001). Similar results were found when nodes tagged at the point of blue dye entry and nodes tagged at the area with the highest radioactive counts were analyzed separately. Our findings suggest that metastatic tumor has a higher probability of being present in the region of the inflow junction of the afferent lymphatic vessel. This information may be useful in determining the optimal method for evaluating axillary sentinel lymph node specimens from breast cancer patients.

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.

Non-sentinel lymph node involvement in patients with breast cancer and sentinel node micrometastasis; too early to abandon axillary clearance

AIMS

It has been suggested that patients with T1-2 breast tumours and sentinel node (SLN) micrometastases, defined as foci of tumour cells smaller than 2 mm, may be spared completion axillary lymph node dissection because of the low incidence of further metastatic disease. To gain insight into the extent of non-sentinel lymph node (n-SLN) involvement, SLNs and complementary axillary clearance specimens in patients with SLN micrometastases were examined.

METHODS

A set of 32 patients with SLN micrometastases was selected on the basis of pathology reports and review of SLNs. Five hundred and thirteen n-SLNs from the axillary clearance specimens were serially sectioned and analysed by means of immunohistochemistry for metastatic disease. Lymph node metastases were grouped as macrometastases (> 2 mm), and micrometastases (< 2 mm), and further subdivided as isolated tumour cells (ITCs) or clusters.

RESULTS

In 11 of 32 patients, one or more n-SLN was involved. Grade 3 tumours and tumours > 2 cm (T2-3 v T1) were significantly associated with n-SLN micrometastases as clusters (grade: odds ratio (OR), 8.3; 95% confidence interval (CI), 1.4 to 50.0; size: T2-3 tumours v T1: OR, 15; 95% CI, 2.18 to 103.0). However, no subgroup of tumours with regard to size and grade was identified that did not have n-SLN metastases.

CONCLUSIONS

In patients with breast cancer and SLN micrometastases, n-SLN involvement is relatively common. The incidence of metastatic clusters in n-SLN is greatly increased in patients with T2-3 tumours and grade 3 tumours. Therefore, axillary lymph node dissection is especially warranted in these patients. However, because n-SLN metastases also occur in T1 and low grade tumours, even these should be subjected to routine axillary dissection to achieve local control.

The potential therapeutic effect of sentinel lymphadenectomy

Sentinel lymph node (SLN) biopsy in a minimally invasive staging procedure for early breast cancer patients that is currently being investigated in many institutional and multi-institutional studies. Its main perspectives are the omission of axillary dissection in sentinel lymph node-negative patients and an improved staging as a result of more intensive histopathological methods for the detection of nodal involvement. The hypothesis presented in this article suggests that sentinel lymphadenectomy may also serve as a therapeutic intervention in some patients. The background for this comes from historical studies before the general use of systemic adjuvant treatment, which suggest that some node-positive breast cancer patients seem to be curable by locoregional treatment alone. Recent studies show that many patients have nodal metastases limited to the SLNs, where (considering the sigmoid growth model of solid tumours) small metastases may grow faster than larger ones. Large metastases are associated with worse prognosis. It is suggested that, in consequence of its expected therapeutic effects, sentinel lymphadenectomy, i.e. the removal of the lymph nodes most likely to harbour metastases, should be preferred to the omission of axillary dissection, or any other surgical staging procedure based on predictive models of nodal involvement derived from primary tumour characteristics.

Application of a Multigene Reverse Transcription-PCR Assay for Detection of Mammaglobin and Complementary Transcribed Genes in Breast Cancer Lymph Nodes

Background: Mammaglobin mRNA expression is found in 70–80% of primary and metastatic breast tumor biopsies. The potential breast tumor markers B305D, B726P, and γ-aminobutyrate type A receptor π subunit (GABAπ) complement the expression of mammaglobin. Collectively the expression profile of these four genes could be used as a diagnostic and prognostic indicator for breast cancer.

Methods: A multigene reverse transcription-PCR (RT-PCR) assay was established to detect the expression of mammaglobin, GABAπ, B305D, and B726P simultaneously. Specific primers and TaqMan® probes were used to analyze combined mRNA expression profiles in primary breast tumors and metastatic lymph node specimens.

Results: The multigene RT-PCR assay detected substantial expression signals in 27 of 27 primary tumor and 50 of 50 metastatic breast lymph node samples. Specificity studies demonstrated no significant expression signal in 27 non-breast cancer lymph nodes, in 22 various healthy tissue samples, or in 14 colon tumor samples.

Conclusion: The novel RT-PCR-based assay described here provides a sensitive detection system for disseminated breast tumor cells in lymph nodes. In addition, this multigene assay could also be used to test peripheral blood and bone marrow samples.

Application of a multigene reverse transcription-PCR assay for detection of mammaglobin and complementary transcribed genes in breast cancer lymph nodes

BACKGROUND

Mammaglobin mRNA expression is found in 70-80% of primary and metastatic breast tumor biopsies. The potential breast tumor markers B305D, B726P, and gamma-aminobutyrate type A receptor pi subunit (GABApi) complement the expression of mammaglobin. Collectively the expression profile of these four genes could be used as a diagnostic and prognostic indicator for breast cancer.

METHODS

A multigene reverse transcription-PCR (RT-PCR) assay was established to detect the expression of mammaglobin, GABApi, B305D, and B726P simultaneously. Specific primers and TaqMan probes were used to analyze combined mRNA expression profiles in primary breast tumors and metastatic lymph node specimens.

RESULTS

The multigene RT-PCR assay detected substantial expression signals in 27 of 27 primary tumor and 50 of 50 metastatic breast lymph node samples. Specificity studies demonstrated no significant expression signal in 27 non-breast cancer lymph nodes, in 22 various healthy tissue samples, or in 14 colon tumor samples.

CONCLUSION

The novel RT-PCR-based assay described here provides a sensitive detection system for disseminated breast tumor cells in lymph nodes. In addition, this multigene assay could also be used to test peripheral blood and bone marrow samples.

Multiparameter flow cytometry as a tool for the detection of micrometastatic tumour cells in the sentinel lymph node procedure of patients with breast cancer

AIM

To investigate whether multiparameter flow cytometry (MP-FCM) can be used for the detection of micrometastasis in sentinel lymph nodes (SLNs) in breast cancer.

METHODS

Formalin fixed, paraffin wax embedded sentinel lymph nodes (n = 238) from 98 patients were analysed. For each lymph node, sections for haematoxylin and eosin (H&E) staining and immunohistochemistry (IHC) for cytokeratin (MNF116) were cut at three levels with a distance of 500 microm. The intervening material was used for MP-FCM. Cells were immunostained with MNF116, followed by an incubation with fluorescein isothiocyanate (FITC) labelled goat antimouse immunoglobulin. DNA was stained using propidium iodide. From each lymph node 100,000 cells were analysed on the flow cytometer.

RESULTS

Thirty eight of the 98 patients with breast carcinoma showed evidence of metastatic disease in the SLN by one ore more of the three methods. In 37 of 38 cases where metastatic cells were seen in the routine H&E and/or IHC, more than 1% cytokeratin positive cells were detected by MP-FCM. In 24 patients, metastatic foci were more than 2 mm (macrometastasis) and in 14 these foci were smaller than 2 mm (micrometastasis). In three of these 14 cases, MP-FCM revealed positive SLNs, although this was not seen at first glance in the H&E or IHC sections. After revision of the slides, one of these three remained negative. However, MP-FCM analysis of the cytokeratin positive cells showed an aneuploid DNA peak, which was almost identical to that of the primary breast tumour. Duplicate measurements, done in 41 cases, showed a 99% reproducibility. In five of 14 patients with micrometastasis, one or two metastatic foci were found in the non-SLN. However, in 15 of 24 macrometastases multiple non-SLNs were found to have metastatic tumour. All micrometastases except for the remaining negative one mentioned above showed only diploid tumour cells, despite the fact that their primary tumours contained both diploid and aneuploid tumour cells. In primary tumours with more than 60% aneuploid cells, predominantly aneuploid macrometastasis were found, whereas diploid primary tumours only showed diploid micrometastases or macrometastases in their SLN. Aneuploid SLN macrometastases were associated with non-SLN metastases in five of seven patients, whereas diploid cases showed additional non-SLN metastases in only seven of 16 patients.

CONCLUSION

In all cases, MP-FCM was sufficient to detect micrometastatic tumour cells in a large volume of lymph node tissue from SLNs. In some cases it was superior to H&E and IHC staining. Approximately 30% of SLN micrometastases are accompanied by additional non-SLN metastases. The size of the aneuploid fraction (> 60%) in the primary tumour may influence the risk of having both SLN and non-SLN metastases.

Occult axillary lymph node metastases are of no prognostic significance in breast cancer

The significance of occult metastases in axillary lymph nodes in patients with carcinoma of the breast is controversial. Additional sections were cut from the axillary lymph nodes of 477 women with invasive carcinoma of the breast, in whom no metastases were seen on initial assessment of haematoxylin and eosin stained sections of the nodes. One section was stained with haematoxylin and eosin, and one using immunohistochemistry with two anti-epithelial antibodies (CAM5.2 and HMFG2). Occult metastases were found in 60 patients (13%). The median follow-up was 18.9 years with 153 breast cancer related deaths. There was no difference in survival between those with and those without occult metastases. Multivariate analysis, however, showed that survival was related to tumour size and histological grade. This node-negative group was compared with a second group of 202 patients who had one involved axillary node found on initial assessment of the haematoxylin and eosin sections; survival was worse in the patients in whom a nodal metastasis was found at the time of surgery. Survival was not related to the size of nodal metastases in the occult metastases and single node positive groups. Some previous studies have found a worse prognosis associated with occult metastases on univariate analysis, but the evidence that it is an independent prognostic factor on multivariate analysis is weak. We believe that the current evidence does not support the routine use of serial sections or immunohistochemistry for the detection of occult metastases in the management of lymph node negative patients, but that the traditional factors of histological grade and tumour size are useful.

Internal mammary lymph nodes and sentinel node biopsy in breast cancer

The long-term follow-up of patients treated with extended radical mastectomy has proved that the internal mammary node (IMN) status is an important prognosticator of breast cancer. Patients with isolated IMN involvement seem to have the same outcome as those with limited axillary disease, and these patients may therefore be overstaged in the TNM system. Sentinel node biopsy (SNB) of IMNs may be an ideal staging procedure, but lymphatic mapping studies demonstrate that data from extended radical mastectomy series cannot be extrapolated to patients suitable for SNB, where the IMN involvement is <5% overall, and around 1% for IMN metastases without axillary disease. Current evidence does not allow internal mammary SNB to be recommended as a standard procedure, but as patients with IMN involvement may benefit from adjuvant systemic treatment, internal mammary SNB should be further studied in this context.

Pathologic analysis of sentinel lymph nodes

The sentinel lymph node (SLN) procedure enables selective targeting of the first draining lymph node, where the initial metastases will form. A negative SLN predicts the absence of tumor metastases in the other regional lymph nodes with a high degree of accuracy. This means that in case of a negative SLN, regional lymph node dissection is no longer necessary. Besides saving patients the significant morbidity associated with lymph node dissection, it will also save costs. Crucial for the success of the SLN procedure is the screening of the SLN for metastases by the pathologist. To this end, several techniques are available such as standard histo- and cytopathological techniques, immunohistochemistry, flow cytometry, and molecular biological techniques. In this paper, the value of these methods for detecting SLN metastases is discussed. Some of these techniques have also appeared to be quite useful for intraoperative evaluation of SLNs. The standard protocol for detection of SLN metastases consists of extensive histopathological investigation including stepped sections stained with hematoxylin and eosin (HE) and immunohistochemistry. Intraoperative frozen section analysis and imprint cytology of SLNs have been shown to be reasonably reliable for detecting breast cancer metastases in SLNs. Further studies are necessary to establish the role of multiparameter flow cytometry and sophisticated molecular biological techniques such as reverse transcription polymerase chain reaction (RT-PCR) in detecting SLN metastases.