Prognostic impact of macrometastasis linear size in sentinel node biopsy for breast carcinoma.

AIM: The aim of the present study was to evaluate the risk of axillary non-sentinel lymph-node metastases (ALN) in breast cancer patients presenting macrometastasis (Mac-m) in the sentinel lymph node (SN). MATERIALS AND METHODS: A retrospective series of 1464 breast cancers from patients who underwent ALN dissection following the diagnosis of Mac-m in the sentinel node (SN) was studied. In all the cases the MAC-m linear size was evaluated and correlated with presence or absence of non-SN ALN metastases. RESULTS: Non-SN metastases were detected in 644∖1464 cases (43.98%). The risk of further axillary metastases ranged from 20.2% (37/183) in cases with Mac-m between 2 and 2.9 mm, to 65.3% (262/401) in cases with Mac-m measuring > 10 mm. The risk of non-SN ALN metastases showed a 3% increase, parallel to each mm increment in SN metastasis size. The data evaluated with the receiver operating characteristic (ROC) curve showed that the Mac-m could be subdivided according to a new cut-off of 7 mm. pT1 tumours, with Mac-m < 7 mm had a risk of non-SN ALN metastases of <30%. Furthermore 109/127 of these (85.8%) had 3 or less non-SN ALN -metastases. CONCLUSIONS: The present data give a detailed description on the risk of non-SN ALN involvement, that may be useful in the evaluation of breast cancer patients. It is suggested that a Mac-m size of <7 mm is related to a low residual axillary disease burden in breast cancer patients with small (pT1) tumours.

Consistency in recognizing microinvasion in breast carcinomas is improved by immunohistochemistry for myoepithelial markers.

Microinvasion is the smallest morphologically identifiable stage of invasion. Its presence and distinction from in situ carcinoma may have therapeutic implications, and clinical staging also requires the recognition of this phenomenon. Microinvasion is established on the basis of several morphological criteria, which may be difficult and not perfectly reproducible among pathologists. The aim of this study was to assess the consistency of diagnosing microinvasion in the breast on traditional haematoxylin and eosin (HE) stained slides and to evaluate whether immunohistochemistry (IHC) for myoepithelial markers could improve this. Digital images were generated from representative areas of 50 cases stained with HE and IHC for myoepithelial markers. Cases were specifically selected from the spectrum of in situ to microinvasive cancers. Twenty-eight dedicated breast pathologists assessed these cases at different magnifications through a web-based platform in two rounds: first HE only and after a washout period by both HE and IHC. Consistency in the recognition of microinvasion significantly improved with the use of IHC. Concordance rates increased from 0.85 to 0.96, kappa from 0.5 to 0.85, the number of cases with 100% agreement rose from 9/50 to 25/50 with IHC and the certainty of diagnosis also increased. The use of IHC markedly improves the consistency of identifying microinvasion. This corroborates previous recommendations to use IHC for myoepithelial markers to clarify cases where uncertainty exists about the presence of microinvasion. Microinvasive carcinoma is a rare entity, and seeking a second opinion may avoid overdiagnosis.

Variations of dissection properties and mass fractions with thrombus age in human abdominal aortic aneurysms.

INTRODUCTION: Thrombus ages, defined as four relative age phases, are related to different compositions of the intraluminal thrombus (ILT) in the abdominal aortic aneurysm (AAA) (Tong et al., 2011b). Experimental studies indicate a correlation between the relative thrombus age and the strength of the thrombus-covered wall. METHODS: On 32 AAA samples we performed peeling tests with the aim to dissect the material (i) through the ILT thickness, (ii) within the individual ILT layers and (iii) within the aneurysm wall underneath the thrombus by using two extension rates (1mm/min, 1mm/s). Histological investigations and mass fraction analysis were performed to characterize the dissected morphology, to determine the relative thrombus age, and to quantify dry weight percentages of elastin and collagen in the AAA wall. RESULTS: A remarkably lower dissection energy was needed to dissect within the individual ILT layers and through the thicknesses of old thrombi. With increasing ILT age the dissection energy of the underlying intima-media composite continuously decreased and the anisotropic dissection properties for that composite vanished. The quantified dissection properties were rate dependent for both tissue types (ILT and wall). Histology showed that single fibrin fibers or smaller protein clots within the ILT generate smooth dissected surfaces during the peeling. There was a notable decrease in mass fraction of elastin within the thrombus-covered intima-media composite with ILT age, whereas no significant change was found for that of collagen. CONCLUSIONS: These findings suggest that intraluminal thrombus aging leads to a higher propensity of dissection for the ILT and the intima-media composite of the aneurysmal wall.

The requirements of a specialist Breast Centre.

INTRODUCTION: In recognition of the advances and evidence based changes in clinical practice that have occurred in recent years and taking into account the knowledge and experience accumulated through the voluntary breast unit certification programme, Eusoma has produced this up-dated and revised guidelines on the requirements of a Specialist Breast Centre (BC). METHODS: The content of these guidelines is based on evidence from the recent relevant peer reviewed literature and the consensus of a multidisciplinary team of European experts. The guidelines define the requirements for each breast service and for the specialists who work in specialist Breast Centres. RESULTS: The guidelines identify the minimum requirements needed to set up a BC, these being an integrated Breast Centre, dealing with a sufficient number of cases to allow effective working and continuing expertise, dedicated specialists working with a multidisciplinary approach, providing all services throughout the patients pathway and data collection and audit. It is essential that the BC also guarantees the continuity of care for patients with advanced (metastatic) disease offering treatments according to multidisciplinary competencies and a high quality palliative care service. The BC must ensure that comprehensive support and expertise may be needed, not only through the core BC team, but also ensure that all other medical and paramedical expertise that may be necessary depending on the individual case are freely available, referring the patient to the specific care provider depending on the problem. CONCLUSIONS: Applying minimum requirements and quality indicators is essential to improve organisation, performance and outcome in breast care. Efficacy and compliance have to be constantly monitored to evaluate the quality of patient care and to allow appropriate corrective actions leading to improvements in patient care.

The predictive value of serum soluble E-cadherin levels in breast cancer patients undergoing preoperative systemic chemotherapy.

OBJECTIVES: To date, no reliable markers are available to predict response to or to assess prognosis after preoperative systemic chemotherapy (PST) in patients with locally advanced breast cancer. Previous studies demonstrated that elevated levels of soluble E-cadherin (sE-cadherin), a product of proteolytic cleavage of cell surface E-cadherin, are associated with higher risk for metastatic disease and poor prognosis in various tumor types. We, therefore, hypothesized that serum sE-cadherin levels measured before PST may correlate with pathological response. DESIGN AND METHODS: In a retrospective analysis, sE-cadherin levels were measured in sera of 108 female patients with histologically proven breast cancer before initiation of PST by using a commercially available quantitative sandwich enzyme immunoassay technique. Patients received a median number of 4 (range 3-6) cycles of anthracyline-based chemotherapy. The median patient age was 51.5 (range 21-71) years. Tumor size was measured clinically and translated into the tumor-node-metastasis (TNM)-system before the start of chemotherapy. Histopathological response in surgically removed specimens was evaluated using a modified Sinn regression score. In univariate analyses the correlations between levels of sE-cadherin and pathological response to PST were calculated. RESULTS: The histopathological regression scores correlated significantly with tumor grading (p=0.045), clinical lymph node status before PST (p=0.031) and sE-cadherin levels (p=0.039). No correlation was seen between histopathological regression scores and hormone receptor and menopausal status as well as Her2-neu status. CONCLUSION: sE-cadherin may be a marker predicting response to PST for patients with breast cancer. Our findings warrant further evaluation of sE-cadherin in a prospective trial.

International multicenter tool to predict the risk of four or more tumor-positive axillary lymph nodes in breast cancer patients with sentinel node macrometastases.

Recently, many centers have omitted routine axillary lymph node dissection (ALND) after metastatic sentinel node biopsy in breast cancer due to a growing body of literature. However, existing guidelines of adjuvant treatment planning are strongly based on axillary nodal stage. In this study, we aim to develop a novel international multicenter predictive tool to estimate a patient-specific risk of having four or more tumor-positive axillary lymph nodes (ALN) in patients with macrometastatic sentinel node(s) (SN). A series of 675 patients with macrometastatic SN and completion ALND from five European centers were analyzed by logistic regression analysis. A multivariate predictive model was created and validated internally by 367 additional patients and then externally by 760 additional patients from eight different centers. All statistical tests were two-sided. Prevalence of four or more tumor-positive ALN in each center's series (P = 0.010), number of metastatic SNs (P < 0.0001), number of negative SNs (P = 0.003), histological size of the primary tumor (P = 0.020), and extra-capsular extension of SN metastasis (P < 0.0001) were included in the predictive model. The model's area under the receiver operating characteristics curve was 0.766 in the internal validation and 0.774 in external validation. Our novel international multicenter-based predictive tool reliably estimates the risk of four or more axillary metastases after identifying macrometastatic SN(s) in breast cancer. Our tool performs well in internal and external validation, but needs to be further validated in each center before application to clinical use.

[Quality of conventional PAP smears. Quality assessment and motivation for improvement]. / Qualität des konventionellen PAP-Abstrichs. Qualitätserhebung und Motivierung zur Verbesserung.

The success of cytology in screening programs for cervical cancer is highly dependent on the smear quality. Interdisciplinary projects which evaluate the smear quality and the results of collection devices could be helpful for an improvement and a successful example for quality improvement is presented here. An average of 83% technically adequate and representative smears was documented for 12 million conventional PAP smears; however only an average of 68% technically adequate and representative smears was found for the group of least successful smear takers of all laboratories. This indicates a potential for improvement. Following an interdisciplinary project on smear quality improvement the average rate of representative smears increased from 69 to 83% and in another project this rate remained stable at 86%. Based on 158,411 conventional smears, representative smears were achieved in 92% using Cervex-Brush®, 86% using Szalay Spatula and 82% Cytobrush methods. The combinations of Cytobrush with the Ayre wooden spatula, cotton wool swab or Szalay Spatula achieved 97%, 94% and 92% representative smears, respectively.

Multicentre validation of different predictive tools of non-sentinel lymph node involvement in breast cancer.

Sentinel lymph node (SN) biopsy offers the possibility of selective axillary treatment for breast cancer patients, but there are only limited means for the selective treatment of SN-positive patients. Eight predictive models assessing the risk of non-SN involvement in patients with SN metastasis were tested in a multi-institutional setting. Data of 200 consecutive patients with metastatic SNs and axillary lymph node dissection from each of the 5 participating centres were entered into the selected non-SN metastasis predictive tools. There were significant differences between centres in the distribution of most parameters used in the predictive models, including tumour size, type, grade, oestrogen receptor positivity, rate of lymphovascular invasion, proportion of micrometastatic cases and the presence of extracapsular extension of SN metastasis. There were also significant differences in the proportion of cases classified as having low risk of non-SN metastasis. Despite these differences, there were practically no such differences in the sensitivities, specificities and false reassurance rates of the predictive tools. Each predictive tool used in clinical practice for patient and physician decision on further axillary treatment of SN-positive patients may require individual institutional validation; such validation may reveal different predictive tools to be the best in different institutions.

Effects of age on the elastic properties of the intraluminal thrombus and the thrombus-covered wall in abdominal aortic aneurysms: biaxial extension behaviour and material modelling.

OBJECTIVE: The intraluminal thrombus (ILT) present in the majority of abdominal aortic aneurysms (AAAs) plays an important role in aneurysm wall weakening. Studying the age-dependent elastic properties of the ILT and the thrombus-covered wall provides a better understanding of the potential effect of ILT on AAA remodelling. MATERIALS AND METHODS: A total of 43 AAA samples (mean age 67 ± 6 years) including ILT and AAA wall was harvested. Biaxial extension tests on the three individual ILT layers and the thrombus-covered wall were performed. Histological investigations of the thrombi were performed to determine four different age phases, and to correlate with the change in the mechanical properties. A three-dimensional material model was fitted to the experimental data. RESULTS: The luminal layers of the ILT exhibit anisotropic stress responses, whereas the medial and the abluminal layers are isotropic materials. The stresses at failure in the equibiaxial protocol continuously decrease from the luminal to the abluminal side, whereby cracks, mainly oriented along the longitudinal direction, can be observed in the ruptured luminal layers. The thrombi in the third and fourth phases contribute to wall weakening and to an increase of the mechanical anisotropy of their covered walls. The material models for the thrombi and the thrombus-covered walls are in excellent agreement with the experimental data. CONCLUSION: Our results suggest that thrombus age might be a potential predictor for the strength of the wall underneath the ILT and AAA rupture.

Practice of HER-2 immunohistochemistry in breast carcinoma in Austria.

Practice and accuracy of immunohistochemistry is known to vary highly. Reliability of HER-2 immunohistochemistry is critical because of its role in patient selection for therapeutical options in breast cancer. Therefore reliability of HER-2 immunohistochemistry in pathology laboratories in Austria was assessed. Ten tissue specimens of invasive ductal breast carcinomas and three cell line samples were tested. Presence/absence of gene amplification was determined by FISH to be used as a gold standard. Laboratories were asked to stain and assess slides using their routine immunohistochemical staining protocol. Overall the study consisted of 311 tests on tissue specimens and 142 on cell lines. In all cases manual scoring was performed. Participation was voluntary and was 94%. Overall sensitivity was 90.5% and specificity 99.2%. Overscoring including true false positive results were found in 6.7% and 6.3% in tissue specimens and cell lines, respectively. False negative determinations were obtained in 1.9% and 2.8% of tissue specimens and cell lines, respectively. HercepTest showed slightly higher reliability in comparison with individualized staining methods. By manual scoring inaccurate scoring affected 12.3% of test results and 62% of the laboratories. In conclusion participation rate and accuracy of HER-immunohistochemistry was high all over the country. Manually performed scoring demonstrated some limitations.

A methodology to study the morphologic changes in lesions during in vitro angioplasty using MRI and image processing.

The assessment of morphologic changes in atherosclerotic lesions during interventional procedures such as transluminal balloon angioplasty is an issue of highest clinical importance. We propose a methodology that allows realistic 3D morphomechanical modeling of the vessel, the plaque and the lumen at different stages of in vitro angioplasty. We elaborate on a novel device designed to guide angioplasty under controlled experimental conditions. The device allows to reproduce in vivo conditions as good as possible, i.e. axial in situ pre-stretch, 100mmHg intraluminal pressure, 37 degrees C Tyrode solution, balloon inflation without external constraints using a high-pressure syringe and contrast medium. With a standard 1.5T MR-system we accomplish multi-spectral images at different stages of the angioplasty experiment. After MR image acquisition the specimen is used for histopathological analysis and biomechanical tests. A segmentation process is used to generate NURBS-based 3D geometric models of the individual vessel and plaque components at different balloon pressures. Tissue components are segmented automatically using generalized gradient vector flow active contours. We investigated 10 human femoral arteries. The effects of balloon compression on the individual artery components is particularly described for two obstructed arteries with an intact collagenous cap, a pronounced lipid pool and with calcification. In both arteries we observe a significant increase in lumen area after angioplasty. Dissection between intima and media and reduction of the lipid pool are primary mechanisms of dilatation. This methodology provides a basis for studying plaque biomechanics under supra-physiological loading conditions. It has the potential to improve and validate finite element models of atherosclerotic plaques which may allow a better prediction of angioplasty procedures.

[Reevaluation of cytological smears in patients with cervical cancer. Regional quality assurance program with the cooperation of the Austrian Society for Cytology, the Carinthian Medical Association and the Carinthian Ministry of Health]. / Reevaluation von Zervixabstrichen bei Zervixkarzinompatientinnen. Regionales Qualitätssicherungsprogramm unter Mitwirkung der Osterreichischen Gesellschaft für Zytologie, der Kärntner Arztekammer und der Landessanitätsdirektion Kärntens.

BACKGROUND AND METHODS: To evaluate the reasons for the occurrence of invasive cervical cancer in Carinthia despite cytological screening, all 132 patients diagnosed with cervical cancer in the years 2000-2002 were recorded and all gynecological cytological smears made within the 5 years prior to the diagnosis of cancer were reevaluated. RESULTS: Within the 5 years prior to diagnosis, no gynaecological cytological smear was found for 50% of the patients diagnosed with cervical cancer in the years 2000-2002. In the year 2002, a total of 53 patients were reported to have cervical cancer and 78 smears were reevaluated. Of all the smears primarily diagnosed as negative, 49% were found to be positive (> or =Pap III) after reevaluation and 92% of all smears "correctly" diagnosed as negative showed quality deficiencies. The interobserver variability (kappa-statistics) showed a moderate value when the primary screening results were compared with the reevaluation. The interobserver variability within the group of reevaluators was also moderate.

Flat epithelial atypia (DIN 1a, atypical columnar change): an underdiagnosed entity very frequently coexisting with lobular neoplasia.

AIMS: Flat epithelial atypia of the breast [FEA; synonyms: ductal intraepithelial neoplasia (DIN) 1a, atypical columnar change] is increasingly recognized by pathologists and shows distinct genetic alterations. The aim of this study was to determine its biological significance as an incidental finding in breast biopsy specimens. METHODS AND RESULTS: On the assumption that both FEA and lobular neoplasia (LN) derive from progenitor cells in the terminal ductal-lobular unit, we investigated the association between FEA and LN semiquantitatively in 111 excisional breast biopsy specimens which contained LN, but did not contain ductal carcinoma in situ (DCIS) or invasive carcinoma. Ninety-six cases (86.5%) revealed coexistence of LN and FEA (P < 0001). The distribution of LN was focal in 41 cases (37%), multifocal in 50 (45%) and extensive in 20 (18%) cases. FEA was identified as focal, multifocal and extensive in 29 (26%), 42 (38%) and 25 (23%) cases, respectively. Distribution patterns of LN and FEA showed no statistically significant correlation. CONCLUSIONS: Due to the striking association between LN and FEA in our material, one may speculate that these two lesions are biologically related and that FEA is an early but non-obligate precursor lesion similar to LN. Based on this assumption, regular clinical and mammographic follow-up of patients with FEA would be prudent.

The value of cytokeratin immunohistochemistry in the evaluation of axillary sentinel lymph nodes in patients with lobular breast carcinoma.

BACKGROUND: Cytokeratin immunohistochemistry (IHC) reveals a higher rate of occult lymph node metastases among lobular carcinomas than among ductal breast cancers. IHC is widely used but is seldom recommended for the evaluation of sentinel lymph nodes in breast cancer patients. OBJECTIVE: To assess the value of cytokeratin IHC for the detection of metastases in sentinel lymph nodes of patients with invasive lobular carcinoma. METHODS: The value of IHC, the types of metastasis found by this method, and the involvement of non-sentinel lymph nodes were analysed in a multi-institutional cohort of 449 patients with lobular breast carcinoma, staged by sentinel lymph node biopsy and routine assessment of the sentinel lymph nodes by IHC when multilevel haematoxylin and eosin staining revealed no metastasis. RESULTS: 189 patients (42%) had some type of sentinel node involvement, the frequency of this increasing with increasing tumour size. IHC was needed for identification of 65 of these cases: 17 of 19 isolated tumour cells, 40 of 64 micrometastases, and 8 of 106 larger metastases were detected by this means. Non-sentinel-node involvement was noted in 66 of 161 cases undergoing axillary dissection. Although isolated tumour cells were not associated with further lymph node involvement, sentinel node positivity detected by IHC was associated with further nodal metastases in 12 of 50 cases (0.24), a proportion that is higher than previously reported for breast cancer in general. CONCLUSIONS: IHC is recommended for the evaluation of sentinel nodes from patients with lobular breast carcinoma, as the micrometastases or larger metastases demonstrated by this method are often associated with a further metastatic nodal load.

In situ tensile testing of human aortas by time-resolved small-angle X-ray scattering.

The collagen diffraction patterns of human aortas under uniaxial tensile test conditions have been investigated by synchrotron small-angle X-ray scattering. Using a recently designed tensile testing device the orientation and d-spacing of the collagen fibers in the adventitial layer have been measured in situ with the macroscopic force and sample stretching under physiological conditions. The results show a direct relation between the orientation and extension of the collagen fibers on the nanoscopic level and the macroscopic stress and strain. This is attributed first to a straightening, second to a reorientation of the collagen fibers, and third to an uptake of the increasing loads by the collagen fibers.

Single lamellar mechanics of the human lumbar anulus fibrosus.

The mechanical behavior of the entire anulus fibrosus is determined essentially by the tensile properties of its lamellae, their fiber orientations, and the regional variation of these quantities. Corresponding data are rare in the literature. The paper deals with an in vitro study of single lamellar anulus lamellae and aims to determine (i) their tensile response and regional variation, and (ii) the orientation of lamellar collagen fibers and their regional variation. Fresh human body-disc-body units (L1-L2, n=11) from cadavers were cut midsagittally producing two hemidisc units. One hemidisc was used for the preparation of single lamellar anulus specimens for tensile testing, while the other one was used for the investigation of the lamellar fiber orientation. Single lamellar anulus specimens with adjacent bone fragments were isolated from four anatomical regions: superficial and deep lamellae (3.9+/-0.21 mm, mean +/- SD, apart from the outer boundary surface of the anulus fibrosus) at ventro-lateral and dorsal positions. The specimens underwent cyclic uniaxial tensile tests at three different strain rates in 0.15 mol/l NaCl solution at 37 degrees C, whereby the lamellar fiber direction was aligned with the load axis. For the characterization of the tensile behavior three moduli were calculated: E(low) (0-0.1 MPa), E(medium) (0.1-0.5 MPa) and E(high) (0.5-1 MPa). Additionally, specimens were tested with the load axis transverse to the fiber direction. From the second hemidisc fiber angles with respect to the horizontal plane were determined photogrammetrically from images taken at six circumferential positions from ventral to dorsal and at three depth levels. Tensile moduli along the fiber direction were in the range of 28-78 MPa (regional mean values). Superficial lamellae have larger E(medium) (p=0.017) and E(high) (p=0.012) than internal lamellae, and the mean value of superficial lamellae is about three times higher than that of deep lamellae. Tensile moduli of ventro-lateral lamellae do not differ significantly from the tensile moduli of dorsal lamellae, and E(low) is generally indifferent with respect to the anatomical region. Tensile moduli transverse to the fiber direction were about two orders of magnitude smaller (0.22+/-0.2 MPa, mean +/- SD, n=5). Tensile properties are not correlated significantly with donor age. Only small viscoelastic effects were observed. The regional variation of lamellar fiber angle phi is described appropriately by a regression line |phi|=23.2 + 0.130 x alpha (r(2)=0.55, p<0.001), where alpha is the polar angle associated with the circumferential position. The single anulus lamella may be seen as the elementary structural unit of the anulus fibrosus, and exhibits marked anisotropy and distinct regional variation of tensile properties and fiber angles. These features must be considered for appropriate physical and numerical modeling of the anulus fibrosus.

Consistency of staining and reporting of oestrogen receptor immunocytochemistry within the European Union--an inter-laboratory study.

To assess the variability of oestrogen receptor (ER) testing using immunocytochemistry, centrally stained and unstained slides from breast cancers were circulated to the members of the European Working Group for Breast Screening Pathology, who were asked to report on both slides. The results showed that there was almost complete concordance among readers (kappa=0.95) in ER-negative tumours on the stained slide and excellent concordance among readers (kappa=0.82) on the slides stained in each individual laboratory. Tumours showing strong positivity were reasonably well assessed (kappa=0.57 and 0.4, respectively), but there was less concordance in tumours with moderate and low levels of ER, especially when these were heterogeneous in their staining. Because of the variation, the Working Group recommends that laboratories performing these stains should take part in a external quality assurance scheme for immunocytochemistry, should include a tumour with low ER levels as a weak positive control and should audit the percentage positive tumours in their laboratory against the accepted norms annually. The Quick score method of receptor assessment may also have too many categories for good concordance, and grouping of these into fewer categories may remove some of the variation among laboratories.

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.