Results of a national training programme in sentinel lymph node biopsy for breast cancer.

BACKGROUND: New Start, a structured, validated, multidisciplinary training programme in sentinel lymph node biopsy (SLNB), was established to allow the introduction and rapid transfer of appropriate knowledge and technical skills to ensure safe and competent practice across the UK. METHODS: Multidisciplinary teams attended a theory/skills laboratory course, following which they performed 30 consecutive SLNBs, either concurrently with their standard axillary staging procedure (training model A) or as stand-alone SLNB (training model B). SLNB was performed according to a standard protocol using the combined technique of isotope ((99m) Tc-labelled albumin colloid) and blue dye. An accredited New Start trainer mentored the first five procedures in the participant's hospital, or all 30 if stand-alone. Validation standards for model A and B were a localization rate of at least 90 per cent. In addition, for model A only, in which a minimum of ten patients were required to be node-positive, a false-negative rate (FNR) of 10 per cent or less was required. RESULTS: From October 2004 to December 2008, 210 SLNB-naive surgeons, in 103 centres, performed 6685 SLNB procedures. The overall sentinel lymph node (SLN) localization rate was 98·9 (95 per cent confidence interval 98·6 to 99·1) per cent (6610 of 6685) and the FNR 9·1 (7·9 to 10·5) per cent (160 of 1757). The FNR was related to nodal yield, ranging from 14·8 per cent for one node and declining to 9·7, 6·6, 4·7 and 4·1 per cent for two, three, four and more than four SLNs respectively. No learning curve was identified for localization or FNR. CONCLUSION: The programme successfully trained a wide range of UK breast teams to perform safe SLNB and suggested that a standard injection protocol and structured multidisciplinary training can abolish learning curves.

Axillary node staging by ultrasonography and fine-needle aspiration cytology in patients with breast cancer.

BACKGROUND: This study evaluated the role of axillary ultrasonography (AUS) and fine-needle aspiration cytology (FNAC) in preoperative staging of the axilla in patients with invasive breast cancer. METHODS: Between October 2006 and March 2009, 502 patients scheduled to undergo surgery for invasive breast cancer had preoperative AUS. All patients with suspicious nodes on ultrasonography underwent FNAC, and those with positive cytology proceeded directly to axillary node clearance. Patients with normal findings on AUS or negative cytology underwent sentinel node biopsy (SNB). RESULTS: A total of 137 (27.3 per cent) of 502 patients had axillary node metastases on final histology. Thirty-nine (28.5 per cent) node-positive patients were identified by AUS-FNAC and spared unnecessary SNB. AUS-FNAC had a sensitivity of 28.5 per cent and a specificity of 100 per cent for detecting axillary nodal metastases. AUS-FNAC findings were normal in all 15 patients with nodal micrometastases and in 11 patients with isolated tumour cells on histopathology. The sensitivity of AUS-FNAC had a positive correlation with invasive tumour size (odds ratio 1.03) and grade (odds ratio 2.80). CONCLUSION: Preoperative AUS-FNAC avoided unnecessary SNB in 28.5 per cent of node-positive patients and in 7.8 per cent of patients overall.

Expression of the WASP verprolin-homologues (WAVE members) in human breast cancer.

BACKGROUND: The WASP family proteins have been indicated to play a vital role in the formation of membrane protrusions required for cell locomotion. WAVE proteins are an important subfamily that also plays a crucial role in actin polymerisation, which is vital to cell migration. However, not much is known about the clinical significance of this subfamily in cancers. We report, for the first time, the expression of the WAVE molecules, at protein and mRNA levels, in human breast cancer. MATERIALS AND METHODS: The expression of the 3 WAVE molecules at the mRNA and protein levels in a cohort of 122 human breast cancers and 32 normal breast tissues were analysed and correlated with the patients' pathological and clinical information as well as outcome (120 months follow-up). RESULTS: All 3 WAVE molecules were detected in mammary tissues. WAVE2 transcripts were expressed in high levels in all breast tumours. Over-expression of WAVE2 was seen in node-positive cases as well as in moderately and poorly differentiated tumours. Also, high levels of WAVE2 expression were associated with death due to disease (p = 0.02) at follow-up. No distinct associations were found between the WAVE1 and WAVE3 transcripts and the breast cancer cells.

Evidence-based management of Mastalgia: a meta-analysis of randomised trials.

Several agents have been utilised for therapy of mastalgia based on data from small trials. No meta-analysis of trials on mastalgia exists. We have conducted a meta-analysis on trials on mastalgia published in the English language. Study was restricted to randomised controlled trials comparing Bromocriptine, Danazol, Evening primrose oil (EPO) and Tamoxifen with placebo. The analysis was carried out on the REVMAN statistical package. Weighted mean difference in the pain score in favour of Bromocriptine was -16.31(95% CI -26.35 to -6.27). Danazol produced a significant benefit with a mean pain score difference -20.23(95% CI -28.12 to -12.34). EPO did not offer any advantage over placebo in pain relief, mean pain score difference being -2.78 (95% CI -7.97 to 2.40). Tamoxifen achieved a relative risk (RR) of pain relief of 1.92 (95% CI 1.42-2.58). Tamoxifen is associated with least side effects and should be the drug of first choice.

Time trends (2006-2015) of quality indicators in EUSOMA-certified breast centres.

AIM OF THE STUDY: The European Society of Breast Cancer Specialists (EUSOMA) has fostered a voluntary certification process for breast centres to establish minimum standards and ensure specialist multidisciplinary care. Prospectively collected anonymous information on primary breast cancer cases diagnosed and treated in the units is transferred annually to a central EUSOMA data warehouse for continuous monitoring of quality indicators (QIs) to improve quality of care. Units have to comply with the EUSOMA Breast Centre guidelines and are audited by peers. The database was started in 2006 and includes over 110,000 cancers from breast centres located in Germany, Switzerland, Belgium, Austria, The Netherlands, Spain, Portugal and Italy. The aim of the present study is assessing time trends of QIs in EUSOMA-certified breast centres over the decade 2006-2015. MATERIALS AND METHODS: Previously defined QIs were calculated for 22 EUSOMA-certified breast centres (46122 patients) during 2006-2015. RESULTS: On the average of all units, the minimum standard of care was achieved in 8 of 13 main EUSOMA QIs in 2006 and in all in 2015. All QIs, except removal of at least 10 lymph nodes at axillary clearance and oestrogen receptor-negative tumours (T > 1 cm or N+) receiving adjuvant chemotherapy, improved significantly in this period. The desirable target was reached for two QIs in 2006 and for 7 of 13 QIs in 2015. CONCLUSION: The EUSOMA model of audit and monitoring QIs functions well in different European health systems and results in better performance of QIs over the last decade. QIs should be evaluated and adapted on a regular basis, as guidelines change over time.

Is mammography overused in male patients?

There is no agreed protocol for the use of mammography in evaluating the male breast. As a result, the tendency is to use the mammography more often than required. In order to define the role of mammography in men, we carried out a retrospective analysis of all male patients referred to the breast clinic with a history of breast lump between January 2001 and December 2003. The impact of mammography in the evaluation of male breast cancer cases was studied. A total of 220 male patients were referred to the breast clinic during this period. Of these, 134 men had a mammographic examination, with majority (96%) being performed prior to their consultation with the breast clinician as per the clinic protocol. Nine patients under the age of 35 years also had a mammographic evaluation. There were 4 cases of breast cancer diagnosed during this period. Breast cancer was suspected in all patients on clinical examination and was confirmed by biopsy. Breast cancer in men can be suspected on clinical examination in the majority of cases. Mammography appears unnecessary in most men and should not be used as a routine imaging procedure. One should consider imaging only those with clinically suspicious breast lumps to avoid unnecessary imaging particularly in young male patients.

Intraoperative evaluation of axillary sentinel lymph nodes using touch imprint cytology and immunohistochemistry. Part II. Results.

AIM: In order to operate selectively on positive axillae during the initial operative session for early breast cancer, an accurate and rapid intraoperative method to examine an axillary node sample (ANS) or a sentinel node biopsy (SNB) is required. The aim of this study was to determine the feasibility and accuracy of Immunohistochemistry (IHC)-stained touch imprints in detecting metastatic axillary nodes intraoperatively. MATERIAL AND METHODS: Four hundred and thirty-two axillary nodes from 52 patients (23 axillary node clearance (ANC), 15 ANS and 14 SNB) were bisected, imprinted and stained with anti-cytokeratin 19 IHC. Results were compared with those of routine haematoxylin and eosin (H&E)-stained sections. RESULTS: IHC imprints detected 32 positive nodes from 12 patients. H&E sections detected 31 positive nodes from 11 patients. IHC imprints missed metastases in three nodes and missed the diagnosis of positive axillae in two patients. H&E missed metastases in four nodes and missed the diagnosis of positive axillae in 3 patients. On a node-basis, sensitivities were 91.4 and 88.5%, negative predictive values (NPV) were 99.2 and 99.0% and overall accuracies were 99.3 and 99.1% for IHC imprints and H&E sections, respectively. On a patient-basis, sensitivities were 85.7 and 78.5%, NPVs were 95.2 and 93.1% and overall accuracies were 96.1 and 94.2% for IHC imprints and H&E sections respectively. There were no false positives. Interpretation of the results by a non-histopathologist was concordant with that of a histopathologist. Results might be obtained within 30-45 min depending on the number of examined nodes. CONCLUSION: Intraoperative IHC staining of touch imprints of axillary sentinel nodes is feasible and is a reliable method for evaluating axillary nodes. Slides can be reliably interpreted by a trained non-histopathologist.

Randomized trial of a specialist genetic assessment service for familial breast cancer.

BACKGROUND: Because of the growing demand for genetic assessment, there is an urgent need for information about what services are appropriate for women with a family history of breast cancer. Our purpose was to compare the psychologic impact and costs of a multidisciplinary genetic and surgical assessment service with those of current service provisions. METHODS: We carried out a prospective randomized trial of surgical consultation with (the trial group) and without (the control group) genetic assessment in 1000 women with a family history of breast cancer. All P: values are from two-sided tests. RESULTS: Although statistically significantly greater improvement in knowledge about breast cancer was found in the trial group (P: =.05), differences between groups in other psychologic outcomes were not statistically significant. Women in both groups experienced statistically significant reductions in anxiety and found attending the clinics to be highly satisfying. An initial specialist genetic assessment cost pound 14.27 (U.S. $22.55) more than a consultation with a breast surgeon. Counseling and genetic testing of affected relatives, plus subsequent testing of family members of affected relatives identified as mutation carriers, raised the total extra direct and indirect costs per woman in the trial group to pound 60.98 (U.S. $96.35) over costs for the control subjects. CONCLUSIONS: There may be little benefit in providing specialist genetics services to all women with a family history of breast cancer. Further investigation of factors that may mediate the impact of genetic assessment is in progress and may reveal subgroups of women who would benefit from specialist genetics services.

Regulation of the expression of E-cadherin on human cancer cells by gamma-linolenic acid (GLA).

E-cadherin is a cell to cell adhesion molecule which acts as a suppressor of metastasis. This study examined the effect of gamma-linolenic acid (GLA), a n-6 polyunsaturated fatty acid, on the expression of E-cadherin in human cancer cells. Western blotting studies demonstrated that treatment of cells with GLA for 24 h increased the expression of E-cadherin in lung, colon, breast, melanoma, and liver cancer cells, but not in endothelial cells and fibroblasts. The results were confirmed by immunocytochemistry. In contrast, two other n-6 fatty acids, linoleic acid and arachidonic acid, failed to induce these changes. The increased expression of E-cadherin was correlated with reduced in vitro invasion and increased aggregation, indicating that the increased E-cadherin expression induced by GLA was biologically active. These data add GLA to the short list of E-cadherin up-regulatory factors. The up-regulation of E-cadherin expression in human cancer cells may contribute to the anticancer properties of GLA.

Investigation of a new pure antiestrogen (ICI 182780) in women with primary breast cancer.

We have conducted a clinical trial of a novel pure antiestrogen, 7 alpha-[9-(4,4,5,5,5-pentafluoropentylsulfinyl)nonyl]estra-1,3,5,(1 0)-triene-3,17 beta-diol (ICI 182780), to assess its tolerance, pharmacokinetics, and short term biological effects in women with primary breast cancer. Fifty-six patients were randomized to either a control group (n = 19), in which they received no preoperative treatment, or a treatment group (n = 37), in which they received daily i.m. injections of ICI 182780 at doses of 6 mg (n = 21) or 18 mg (n = 16) for 7 days prior to primary breast surgery. Serum drug concentrations, gonadotropin levels, and sex hormone-binding globulin levels were measured during the study period by radioimmunoassay. Expression of estrogen receptors (ER), progesterone receptors, the estrogen-induced protein pS2, and the cell proliferation-related antigen Ki67 was determined immunocytochemically in pre- and poststudy tumor samples. Treatment with ICI 182780 caused no serious drug-related adverse events and had no effect on serum gonadotropin or sex hormone-binding globulin levels. Minor adverse events occurred in 5 patients receiving the 6-mg dose and 3 patients receiving the 18-mg dose. The serum concentration of ICI 182780 was dose dependent but showed variation between individuals. There was evidence of an approximately 3-fold drug accumulation over the short treatment period but steady state levels were not reached by the end of the 7 days. In patients with ER-positive tumors, treatment with ICI 182780 was associated with significant reductions in the tumor expression of ER (median ER index, 0.72 before versus 0.02 after treatment; P < 0.001), progesterone receptor (median progesterone receptor index, 0.50 before versus 0.01 after treatment; P < 0.05), and Ki67 (median Ki67 labeling index, 3.2 before versus 1.1 after treatment; P < 0.05). Treatment with ICI 182780 also resulted in a significant reduction in pS2 expression (P < 0.05) but this appeared unrelated to tumor ER status. In conclusion, ICI 182780 was well tolerated after short term administration and produced demonstrable antiestrogenic effects in human breast tumors in vivo, without showing evidence of agonist activity. These properties identify ICI 182780 as a candidate agent with which to evaluate whether a pure estrogen antagonist offers any additional benefit in the treatment of human breast cancer over conventional nonsteroidal antiestrogens, typified by tamoxifen, which exhibit variable degrees of agonist activity.

Monoclonal antibody identification and characterization of a Mr 43,000 membrane glycoprotein associated with human breast cancer.

A monoclonal antibody (323/A3) with a high degree of selectivity for binding to breast cancer cells was produced by immunization of mice with MCF-7 human breast cancer cells. The antigen recognized by 323/A3 on MCF-7 appears to be surface localized, and by enzyme-linked immunosorbent assay, the antibody was found to bind strongly with four of six breast cancer cell lines examined while no binding was detectable with nonbreast cancer cell lines. In vivo distribution of the 323/A3 antigen was screened by immunoperoxidase staining of formalin-fixed paraffin sections of normal human tissues and tumors. Among breast tissues, positive staining was detected with 75% (6 of 8) of metastatic lymph nodes, 59% (76 of 128) of primary breast tumors, 20% (13 of 63) of benign breast lesions, and 0% (0 of 10) of normal breast. No immunostaining was detected with a large variety and number of other normal human tissues with the exception of staining observed with epithelium of normal colon. Antigen distribution appears not to be disease specific, since positive staining was also observed with adenocarcinomas other than breast. The antigen recognized by the 323/A3 antibody was identified by Western blot analysis as a Mr 43,000 protein. The glycoprotein nature of the antigen was demonstrated by its binding to concanavalin A, specific elution with sugar, and immunoprecipitation of a Mr 43,000 radiolabeled protein from extracts of MCF-7 cells after pulse labeling with [3H]glucosamine. The 323/A3 antigen appears to be the same Mr 43,000 protein in cell lines as in breast tumors in vivo. Based on a comparison with the molecular weights of other known tumor-associated antigens and with their immunocytochemical tissue distribution, the Mr 43,000 glycoprotein described here represents a tumor-associated antigen previously undescribed in breast cancer or in other tumors. Since the Mr 43,000 glycoprotein is present on the surface of most breast cancer cells and is either absent or expressed at very low levels in most normal tissues including normal breast, the monoclonal antibody described here may have potential applications in diagnosis and management of breast cancer.

Lymphangiogenesis and its role in cancer.

In many tumour types, lymphatic vasculature serves as a major route for tumour metastasis. The dissemination of malignant cells to the regional lymph nodes is an early step in the progression of many solid tumours and is an important determinant of prognosis. Lymphangiogenesis (formation of new lymphatic vessels) is thought to be crucial for cancer cells to metastasise to the regional lymph nodes. However research in this important process has been neglected largely due to the lack of molecular markers specific to the lymphatic endothelium. Recently, several specific markers have been identified including LYVE-1, podoplanin and prox-1. Although the biology of lymphangiogeneis, particularly its regulation, is still far from clear, it is now well established that tumours are lymphangiogenic i.e. they could induce the generation of their own lymphatics and metastasise to the regional lymph nodes. It is thought that the interruption of the main signalling pathways involved in this process could help to prevent lymphatic spread of many tumours. Furthermore, understanding the molecular mechanisms in lymphangiogenesis might help to develop new therapeutic strategies against cancer lymphatic spread. Here, we reviewed the literature in regards to the biology of lymphangiogenesis, its molecular regulation, lymphatic markers and the significance in human solid tumours.

Molecular and cellular mechanisms of lymphangiogenesis.

Lymphangiogenesis is the growth and formation of new lymphatic vessels. It occurs in normally developing tissues and in pathological processes like inflammation, wound healing, lymphoedema and in cancer. New molecular markers that are specific to the lymphatic endothelium include: podoplanin, prox-1 and LYVE-1. The molecular mechanisms of lymphangiogenesis are not clear, but vascular endothelial growth factors (VEGF-C and VEGF-D) within tumours may simulate endothelial cells within tumour tissues to grow and generate new lymphatics. We report the current knowledge of molecular and cellular mechanisms of lymphangiogenesis.

Hepatocyte growth factor modulates vascular endothelial-cadherin expression in human endothelial cells.

Hepatocyte growth factor (HGF)/scatter factor (SF) is a cytokine exerting a wide range of biological functions on many cell types, including vascular endothelial cells. HGF/SF increases migration, motility, and dissociation of human umbilical vascular endothelial cells (HUVECs). This study demonstrated that such action of HGF/SF on HUVECs was achieved by regulation of the endothelial cell-specific cadherin, vascular endothelial (VE)-cadherin. HGF/SF induced a time-dependent reduction of VE-cadherin protein from HUVECs as shown by Western blotting and immunocytochemistry, accompanied by an increase in the migration of HUVECs. The change of VE-cadherin appeared at the mRNA level, as demonstrated by reverse transcription-PCR, with a decrease in the VE-cadherin signal. These results show, for the first time, that HGF/SF targets the endothelial cell-specific adhesion molecule VE-cadherin.

A hammerhead ribozyme suppresses expression of hepatocyte growth factor/scatter factor receptor c-MET and reduces migration and invasiveness of breast cancer cells.

PURPOSE: Hepatocyte growth factor/scatter factor (HGF/SF), via its receptor c-MET, has been implicated to play a pivotal role in breast cancer development and progression. This study examined a transgene-consisting of a combination of U1snRNA, hammerhead ribozyme, and antisense, designed to inhibit c-met expression-and its impact on the migration and in vitro invasion of breast cancer cells. EXPERIMENTAL DESIGN: A hammerhead ribozyme targeting human c-MET was cloned into a modified pZeoU1EcoSpe vector and transfected into breast cancer cells MDA MB 231 and MCF-7 by electroporation. Expression of MET mRNA and protein was determined. Migration and in vitro invasiveness of transfected cells were also analyzed. RESULTS: Breast cancer cells were transfected with the ribozyme-containing plasmids. Stable transfectants manifested an almost complete loss of MET mRNA and protein, as shown by reverse transcription-PCR, Northern blotting, and Western blotting, respectively, whereas the wild-type plasmid had no effects. Met-ribozyme transfected cells exhibited reduced migration and in vitro invasiveness through extracellular matrix (Matrigel), compared with the wild-type cells and cells transfected with empty plasmid. CONCLUSIONS: These data show that targeting c-MET by way of a hammerhead ribozyme encoding antisense to c-MET is an effective approach in reducing the invasiveness of breast cancer cells.

Antagonistic effect of NK4, a novel hepatocyte growth factor variant, on in vitro angiogenesis of human vascular endothelial cells.

Hepatocyte growth factor (HGF), also known as scatter factor (SF), is known to act on cancer cells as well as endothelial cells and stimulate angiogenesis, thus playing an unwanted role in the development and progression of cancer. The current study examined the effects of a newly discovered HGF variant, NK4, on angiogenesis in vitro. Chemically generated NK4 (from recombinant human HGF/SF) was found to be able to inhibit HGF-induced activation (tyrosine phosphorylation) of the HGF/SF receptor cMET but was itself unable to activate cMET. Furthermore, NK4 was demonstrated to inhibit tubule formation from human umbilical vein endothelial cells that was induced by both HGF/SF and a HGF/SF-producing fibroblast (MRC5). Under the same settings, NK4 failed to increase tubular formation. NK4 had no effects on interleukin 8- and vascular endothelial growth factor-induced tubule formation. Using computer-assisted motion analysis, it was further shown that NK4 inhibited HGF-induced migration of human umbilical vein endothelial cells in a migration assay and in an endothelial wounding assay. These data show that NK4 is a complete antagonist to HGF. It inhibits HGF-induced endothelial movement and tubule formation. Thus, NK4 may have an important bearing on the control of cancer progression through its role in angiogenesis. Additional in vivo studies are warranted.

Use of reverse transcription-polymerase chain reaction methodology to detect estrogen-regulated gene expression in small breast cancer specimens.

We describe the development and use of a sensitive reverse transcription-PCR (RT-PCR) procedure to detect novel estrogen-regulated gene expression in small clinical breast cancer samples, in which such study would be extremely difficult by any other molecular or immunocytochemical means. Assay optimization for pLIV1, estrogen receptors (ERs), progesterone receptors, and pS2 gene products was carried out on 50 primary breast cancers for which comparative Northern analysis and immunocytochemical data were available. Using 27 amplification cycles and a 0.5 microM primer concentration, varying expressions of the gene products were recorded simultaneously with a constant densitometric signal for a coamplified endogenous control gene (alpha-actin). Good concordances were subsequently observed between pLIV1 status generated by RT-PCR and both Northern analysis (P = 0.002) and ER status by immunocytochemistry (P = 0.0244). Agreement was also noted between ER (P = 0.002), progesterone receptor (P = 0.0005), and pS2 (P = 0. 0023) RT-PCR and immunocytochemical methodologies. The RT-PCR assays were then applied to 10 needle core trucut biopsies in which similar relationships were obtained. Our results justify the future use of this RT-PCR methodology to examine new estrogen-regulated genes in small breast cancer samples, and it is envisaged that this technology will prove invaluable in many future breast cancer studies.

The sentinel node negative axilla: is it a no-go zone?

The technique of sentinel node biopsy (SNB) presents a great opportunity to reduce the morbidity of surgical treatment of breast cancer. Using either dye, isotope or a combination, after completing a learning process a sensitivity of 80-99% may be achieved. Most surgeons would aim for a sensitivity of 95% but this will mean that 5% of patients will be under-staged, with disease within the axilla and possibly inappropriate advice with regard to adjuvant systemic therapy. Injudicious use of sentinel biopsy will lead to more local relapses and may diminish or neutralize gains from systemic therapy.

Regulation of desmosomal cell adhesion in human tumour cells by polyunsaturated fatty acids.

Desmosomes are key structures in cell-cell adhesion. In this study we examined the effect of n-6 essential fatty acids on the expression of desmoglein (Dsg), desmosomal cadherin and the formation of desmosomes in E-cadherin negative human breast, colon and lung cancer cells and melanoma cells. Electron microscopy revealed that cells cultured with gamma linolenic acid (GLA) showed increased cell-cell adhesion together with an increase in the formation of desmoglein-containing desmosomes. Western blotting studies of cellular proteins demonstrated that, following culture with fatty acids, Dsg expression was modified, with the greatest increase seen after GLA treatment. Other fatty acids increased Dsg expression, but to a lesser extent. It is concluded that GLA regulates desmosome-mediated cell-cell adhesion in human cancer cells, particularly in cells without E-cadherin.

Predictors of non-sentinel lymph node metastasis in breast cancer patients.

In many patients, the sentinel lymph node (SLN) is the sole site of regional nodal metastasis. This subgroup of patients would not be expected to benefit from completion axillary lymph node dissection (CALND). This study evaluated the factors that may determine the likelihood of additional positive nodes in the axilla in the presence of sentinel node metastasis. A total of 618 breast cancer patients underwent SLN biopsy based on lymphoscintigraphy, intraoperative gamma probe detection, and blue dye mapping using 99mTc-nanocolloid and Patent Blue V injected peritumourally. This was followed by standard axillary node clearance at the same operation. Of the 201 patients with a positive SLN, 105 (52%) patients had no further positive nodes in the axilla, 96 (48%) patients had additional metastasis in non-sentinel lymph nodes (NSLN) upon CALND. In patients with a positive SLN, increasing tumour size and tumour grade significantly increased the frequency of additional positive nodes on univariate analysis. The number of SLNs removed and the number of negative SLNs were significant negative predictors. Increasing tumour burden in the sentinel nodes (determined by the number of positive SLNs) was significantly associated with increasing likelihood of positive NSLNs. Multivariate analysis revealed that the rest of the axilla is more likely to be positive if there are more positive than negative SLNs removed and more likely to be negative otherwise. A group of cases from one centre (Cardiff) were subjected to further detailed analysis. Tumour burden in the positive SLN was assessed by measuring the size of metastasis, percentage replacement of the SLN by tumour and by documenting extracapsular extension (ECE) around the SLN. Of the 64 patients with a positive SLN, 34 (53%) patients had no further positive nodes in the axilla, 30 patients (47%) had additional metastasis in NSLNs upon CALND. Increasing tumour burden in the SLN was associated with additional positive nodes in the axilla. Multivariate analysis revealed that size of the SLN metastasis is the most important predictor of involvement of only the SLN. Overall, in patients with a positive SLN, the difference in the number of positive and negative SLNs removed and size of the metastasis in the SLN, all predicted the frequency of additional positive nodes.