Baseline neutrophil-to-lymphocyte ratio (NLR) is associated with outcome of patients treated with BRAF inhibitors.

PURPOSE: The aim of this study is to verify if baseline hematological markers, in patients with advanced melanoma receiving BRAF inhibitor (BRAFi)-based therapies, are independently associated with progression free survival (PFS) and overall survival (OS). METHODS: We retrospectively analyzed 90 patients with metastatic melanoma harboring BRAF V600 mutation, who received treatment with either BRAFi alone or combined with a MEK inhibitor (MEKi) at the recommended dosages. Study population included 28 women and 62 men. Median age was 53 years. Seventy-three (82%) patients presented with M1c disease, 49 (56%) had elevated LDH and 54 (60%) had three or more metastatic sites. RESULTS: The median PFS was 9.1 and 3.5 months, respectively, for patients with baseline NLR < 5 and NLR ≥ 5, while median OS was 17.2 and 5.5 months, respectively, for patients with NLR < 5 and NLR ≥ 5. Multivariate analysis confirmed that baseline NLR < 5 was significantly associated with half risk of relapse (HR = 0.49; 95% CI = 0.28-0.85; p = 0.01) and half risk of death (HR = 0.46; 95% CI = 0.23-0.76; p = 0.004), independent of age, sex, stage, LDH > 2xULN, previous treatments, concomitant use of steroids and type of therapy. In patients with LDH ≥ ULN, NLR < 5 remained significantly and independently associated with improved PFS (HR = 0.28; 95% CI = 0.13-0.62; p = 0.002,) and OS (HR = 0.23; 95% CI = 0.10-0.55; p = 0.001). CONCLUSIONS: These biomarkers are easily reproducible, affordable and costless and NLR could help to identify patients who have the best benefit from BRAF inhibitors.

Dual regulation of Myc by Abl.

The tyrosine kinase c-Abl (or Abl) and the prolyl-isomerase Pin1 cooperatively activate the transcription factor p73 by enhancing recruitment of the acetyltransferase p300. As the transcription factor c-Myc (or Myc) is a known target of Pin1 and p300, we hypothesized that it might be regulated in a similar manner. Consistent with this hypothesis, overexpression of Pin1 augmented the interaction of Myc with p300 and transcriptional activity. The action of Abl, however, was more complex than predicted. On one hand, Abl indirectly enhanced phosphorylation of Myc on Ser 62 and Thr 58, its association with Pin1 and p300 and its acetylation by p300. These effects of Abl were exerted through phosphorylation of substrate(s) other than Myc itself. On the other hand, Abl interacted with the C-terminal domain of Myc and phosphorylated up to five tyrosine residues in its N-terminus, the principal of which was Y74. Indirect immunofluorescence or immunohistochemical staining suggested that the Y74-phosphorylated form of Myc (Myc-pY74) localized to the cytoplasm and coexisted either with active Abl in a subset of mammary carcinomas or with Bcr-Abl in chronic myeloid leukemia. In all instances, Myc-pY74 constituted a minor fraction of the cellular Myc protein. Thus, our data unravel two potential effects of Abl on Myc: first, Abl signaling can indirectly augment acetylation of Myc by p300, and most likely also its transcriptional activity in the nucleus; second, Abl can directly phosphorylate Myc on tyrosine: the resulting form of Myc appears to be cytoplasmic, and its presence correlates with Abl activation in cancer.

Sentinel node biopsy for high-risk cutaneous nonanogenital squamous cell carcinoma: a preliminary result.

BACKGROUND: Certain patients with squamous cell carcinoma (SCC) have much higher rates of regional nodal metastases than is often reported. This study aims to further validate sentinel lymph node biopsy (SNB) for SCC and the outcome of these patients following SNB. METHODS: 20 patients with high-risk nonanogenital SCC who underwent SNB between 1998 and 2007 were retrospectively reviewed. SNB was performed under local or general anesthesia following lymphoscintigraphy and blue dye injection. RESULTS: The median follow-up from SNB was 24 months. Tumor location included the head and neck (n = 11), extremities (n = 9) and trunk (n = 1). One patient had a positive sentinel node. This patient developed parotid metastases 13 months after refusing a complete neck dissection and is alive with progressive disease after 31 months. Two patients developed regional recurrence after negative SNB (1 is alive and disease free, the other died of progressive disease). Of the remaining patients, 15 are alive and disease free, 1 died of another malignancy and 1 was lost to follow-up. CONCLUSION: SNB for high-risk SCC is feasible and allows early detection and treatment of nodal metastases. Currently, SNB for SCC is not a standard treatment and requires further investigation to determine which patients would benefit best from this procedure.

Minimal axillary lymph node involvement in breast cancer has different prognostic implications according to the staging procedure.

It is still controversial whether the identification of micrometastases and isolated tumor cells in the axillary lymph nodes of patients with breast cancer has any prognostic value. We evaluated the prognostic role of isolated tumor cells and micrometastases in the axillary lymph nodes in 3,158 consecutive patients pT1-2 pN0-N1mi (with a single involved lymph node) and M0, referred to the Division of Medical Oncology after surgery performed at the European Institute of Oncology from April 1997 to December 2002. Median follow-up was 6.3 years (range 0.1-11 years). Sentinel lymph node biopsy (SLNB) and axillary lymph node dissection (ALND) were performed in 2,087 and 1,071 patients, respectively. A worse metastasis-free survival was observed for patients with micrometastatic disease compared to node-negative patients, if staged with ALND (log-rank P < .0001; HR: 3.17; 95% CI 1.72-5.83 at multivariate analysis), but not for patients who underwent SLNB (log-rank P = 0.36). The presence of a single micrometastatic lymph node is associated with a higher risk of distant recurrence as compared to node-negative disease only for patients undergoing ALND for staging purposes. Treatment recommendations for systemic therapy should not take into account the presence of a single micrometastatic lymph node identified during complete serial sectioning of sentinel node(s).

[Conservative approach for breast cancer. The experience of the European Institute of Oncology]. / L'approccio conservativo al carcinoma mammario.L'esperienza dell'Istituto Europeo di Oncologia.

Conservative surgery represents the standard care for patients with early breast cancer. The aim of this review was to discuss the extension of conservative surgery in controversial fields such as after primary chemotherapy for large tumours or the possibility to repeat conservative surgery for a local reappearance. The project of a conservative approach to breast cancers continues with sentinel node biopsy which is worldwide performed more and more frequently. In our institute sentinel node biopsy is the standard procedure in the axillary staging of breast cancer even in those clinical scenarios which were previously considered either controversial or a contraindication such as in multicentric breast cancer, during pregnancy, in intra-ductal neoplasias, after primary chemotherapy, and male breast cancer. This conservative approach is completed by the possibility to deliver a partial breast irradiation and to provide patients with more personalized adjuvant treatments tailored on the biological features of the tumour.

Long-term oncological results of breast conservative treatment with oncoplastic surgery.

Oncoplastic surgery combining breast conservative treatment (BCT) and plastic surgery techniques may allow more extensive breast resections and improve aesthetic outcomes, but no long-term oncological results have been published. Long-term oncologic results of 148 consecutive BCT with concomitant bilateral plastic surgery have been analysed and were compared to historical data of BCT trials. Median follow-up was 74 months. Complete excision was obtained in 135 patients (91%); focally involved margins in 8 (5%); and close (<2 mm) margins in 5 (3%). Five patients developed ipsilateral recurrence (3%), 19 (13%) developed distant metastasis and 11 patients died (7.53%). Patients with tumours larger than 2 cm were at greater risk of local recurrences and distant metastasis. Long-term oncologic results of BCT with oncoplastic surgery are comparable with the results of BCT randomized trials.

Breast cancer diagnosed during pregnancy and lactation: biological features and treatment options.

AIM OF THE STUDY: Assessment of biological features and treatment of patients with breast cancer presenting during pregnancy or lactation. PATIENTS AND METHODS: Immunohistochemical analysis of estrogen receptor (ER) and progesterone receptor (PgR), Ki-67, HER2/neu, prognostic markers, treatment and follow-up of 21 patients with breast cancer during pregnancy (BCdP) and 17 with breast cancer during lactation (BCdL) are presented. RESULTS: Median age was 36 and 33 years, median tumour size was 2.4 and 2.5 cm, axillary lymph nodes were positive in 10 of 21 pregnant patients and 11 of 17 lactating patients, respectively. Both ER and PgR were not expressed in six of 21 pregnant women and nine of 17 lactating patients. All the six women who had concurrent diagnosis of breast cancer and pregnancy (first trimester) preferred termination of pregnancy although an alternative option was discussed. Five patients received anthracycline containing chemotherapy during the second and third trimester with no complications for patient and child. Conservative surgery was performed in 15 of 21 patients during pregnancy with no local reappearance after a median follow-up of 24 months. Three pregnant women underwent lymphoscintigraphy and sentinel lymph node biopsy. CONCLUSIONS: Patients who had concurrent diagnosis of breast cancer and pregnancy (early first trimester) preferred termination of pregnancy to allow easier completion of treatment. Conservative surgery was safe also in women with BCdP. Sentinel node biopsy might be considered for pregnant patients with a clinically negative axilla.

Preoperative and perioperative chemotherapy with 5-fluorouracil as continuous infusion in operable breast cancer expressing a high proliferation fraction: cytotoxic treatment during the surgical phase.

BACKGROUND: Experimental data on perioperative chemotherapy (PeCT) indicate that its initiation might be most useful if administered as close as possible to the time of first 'disturbance of the tumour'. Regimens including 5-fluorouracil (5-FU) as continuous infusion are commonly used in the preoperative setting, especially for large tumours and locally advanced disease. We therefore evaluated the role of PeCT with 5-FU as continuous infusion after preoperative chemotherapy (PreCT), covering the surgical phase and acute wound healing period, in patients with breast cancer too large to attempt breast-conserving surgery upon diagnosis. PATIENTS AND METHODS: Breast cancer patients, clinical stages T2-T3, N0-N2, M0, and Ki-67 labelling index >/= 20%, were treated every 3 weeks with a maximum of six courses of vinorelbine 20 mg total dose intravenously (i.v.) on days 1 and 3, cisplatin 60 mg/ m(2) i.v. on day 1 and 5-FU 200 mg/m(2)/day as a continuous infusion (ViFuP regimen). Patients who achieved a clinical and radiological objective remission with PreCT were also treated with perioperative 5-FU that was continued until 30 min before, and restarted immediately after surgery, prolonging infusion until 15 days after surgery. RESULTS: Following preoperative treatment, 39 of 49 evaluable patients [80%; 95% confidence interval (CI) 70% to 90%] had an objective response. Pathological complete remission (pCR) was achieved in 14 (29%) patients. No relevant clinical or haematological toxicity due to PeCT was observed. In 36 patients submitted to PeCT the rate of pCR was 33% (95% CI 18% to 48%). The highest response of the primary tumour to PreCT and PeCT was observed in women with tumours not expressing estrogen and progesterone receptors (pCR 46%; 95% CI 19% to 73%). CONCLUSIONS: Preoperative therapy can be protracted into the surgical (and wound healing) period without significant additional short-term toxicity. Proper selection of patients according to biological features might improve the therapeutic yield of preoperative therapies.

Recognizing features that are dissimilar in male and female breast cancer: expression of p21Waf1 and p27Kip1 using an immunohistochemical assay.

BACKGROUND: Male breast cancer (MBC) is an uncommon disease, and most of our current knowledge of its biology, natural history and treatment has been extrapolated from data on the disease in women. Information is still needed on the molecular biological properties of male breast tumors and their predictive relevance. Kinase inhibitor proteins (KIPs) p27Kip1 and p21Waf1 negatively regulate cell cycle progression by preventing the passage of cycling cells from G1 to S phase through G1 cyclin-dependent kinase activation. No studies exist on the role of these factors in male breast carcinoma. PATIENTS AND METHODS: We have retrospectively analyzed the immunohistochemical expression of p21Waf1 and p27Kip1 protein in 27 primary MBC and in 101 female breast cancers (FBC) treated at the European Institute of Oncology between 1997 and 2000. We also assessed sex hormone receptors status, p53, bcl-2 and c-erb-B2 protein expression, and Ki-67 labeling index. RESULTS: We observed a statistically significant difference in the immunostaining of KIPs p27Kip1 and p21Waf1 in male patients compared with females. Expression of p21Waf1 was observed in 19 of the 27 (70.3%) primary MBCs versus 29 of 101 FBC (29%). Fourteen of 22 negative c-erbB-2 MBCs cases expressed immunostaining for p21Waf1 (P = 0.05). p27Kip1 immunoreactivity was been detected in 26 of 27 (96.2%) male breast patients versus 39 of 101 FBC (39.3%) (P = 0.000). Highly positive staining for P27Kip1 was found in 21 of 25 androgen receptor-expressing samples. Higher levels of p27Kip1 were expressed in bcl-2-positive samples (17 of 20). Eighteen of 22 c-erbB-2-negative cases were strongly immunoreactive for p27Kip1. CONCLUSIONS: p27Kip1 and p21Waf1 immunoreactivity is higher in MBCs compared with FBCs. The findings of higher p27Kip1 and p21Waf1 immunostaining may be an additional predictive factor in MBC. These biological features could be possible indicators for different biological pathways in the tumorigenesis of MBCs.

Internal mammary node lymphoscintigraphy and biopsy in breast cancer.

BACKGROUND: In patients with breast cancer, sentinel nodes (SNs) are detected outside the axilla in 1-2% of cases after superficial injection of radiocolloid in the breast. We investigated whether deep injection of tracer visualized internal mammary chain lymph (IMC) nodes more often, and assessed the impact of IMC status on disease staging. METHODS: A total of 400 patients were enrolled in this trial. The study group included 200 patients with T1-T2 N0 breast cancer in an inner quadrant. Radio tracer was injected superficially in 100 (group A), and deeply under the tumor in the others (group B). If an IMC took up tracer in group B patients it was biopsied. An additional 200 patients with outer quadrant lesions were also studied lymphoscintigraphically following superficial (100 patients) or deep (100 patients) injection, but IMC nodes were not biopsied as this would have required an additional surgical excision. RESULTS: An SN was visualized in the IMC in 65.6% of inner quadrant patients after deep injection and in 2.1% after superficial injection. In outer quadrant patients, deep injection visualized an SN in the IMC in 10% of cases. The IMC SN was located mainly in the 2nd and 3rd intercostal spaces. Radioguided IMC biopsy was performed in 62 patients. Node removal proved simple and risks insignificant. Stage migration occurred in 8% of cases. CONCLUSIONS: Deep injection allows SN localization in the IMC in 65% of inner quadrant breast lesions. Biopsy of the axillary plus IMC resulted in stage migration in 8% of patients. It is unclear whether this additional information can lead to better survival.

Histologic detection and clinical implications of micrometastases in axillary sentinel lymph nodes for patients with breast carcinoma.

BACKGROUND: Sentinel lymph node (SLN) biopsy is used increasingly in patients with clinically lymph node negative, early-stage breast carcinoma, because it can spare axillary dissection when the sentinel lymph nodes are negative. The question arises, however, whether complete axillary lymph node dissection (ALND) also is necessary in patients with only micrometastases (< or = 2 mm in greatest dimension) in axillary SLNs. The authors carried out the current study to ascertain the risk of non-SLN axillary metastases in such patients and to assess the detection rate of SLN micrometastases in relation to the sectioning interval and the number of sections examined. METHODS: The authors examined 109 patients with micrometastatic SLNs from a series of 634 patients with carcinoma of the breast who underwent SLN biopsy and complete ALND as part of the surgical treatment for their disease. The SLNs were sectioned completely at 50-microm intervals, and the sections were examined intraoperatively. RESULTS: The overall frequency of metastases in axillary non-SLNs was 21.8%. The frequency was correlated significantly with the size of the SLN micrometastatic focus (P = 0.02): 36.4% of patients with foci > 1 mm had metastases in axillary lymph nodes--a percentage approaching 44.7% of patients with macrometastatic SLNs--whereas only 15.6% of patients with micrometastases < or = 1 mm had other involved axillary lymph nodes. CONCLUSIONS: Outside of clinical trials, patients with T1 and small T2 breast carcinoma and micrometastatic SLNs should undergo complete ALND for adequate staging. However, patients with SLN micrometastases up to 1 mm in greatest dimension have a significantly lower risk of additional axillary metastases, raising the question of whether ALND may be avoided in this subgroup of patients.

Sentinel node biopsy in head and neck cancer.

The purpose of this study was to assess the value of sentinel node (SN) biopsy in oral cancer by means of a lymphoscintigraphic technique and intraoperative detection by blue-dye combined with gamma-ray probe to facilitate identification of the SN. Forty-one T1-T2N0 patients underwent lymphoscintigraphy, SN biopsy, and modified radical neck dissection. An SN was identified in 39 of 41 patients by the combined use of intraoperative blue dye and the probe and was removed. Complete neck dissections were performed and the histological evaluation compared. Thirty-eight SNs in 35 patients were negative at final pathology and correctly predicted the pathological status of the specimens from the full-neck dissections. Five SNs in four patients had micrometastases and were the only metastatic nodes identified. The results of this study on a homogenous series of patients show that SN biopsy is a valuable staging technique in T1 and T2 oral cancer with uninvolved neck, provided that no previous surgery or radiotherapy has altered lymphatic drainage in the oral cavity or in the neck. In a large number of patients, SN biopsy can avoid unnecessary neck dissection and its relevant morphofunctional sequelae.

Reverse transcription-polymerase chain reaction assay for multiple mRNA markers in the detection of breast cancer metastases in sentinel lymph nodes.

The identification of specific tumor mRNA markers by reverse transcription-polymerase chain reaction might be a valuable diagnostic adjunct for the detection of breast cancer metastases in axillary sentinel lymph nodes (SLNs). In this study we have compared the diagnostic accuracy of an extensive histopathologic examination of 146 SLNs from 123 breast carcinoma patients with that of the evaluation of 5 mRNA markers. When analyzed individually, none of the different markers attained a sensitivity higher than 77.8%, and the general concordance with the histopathologic findings ranged from 78.8 to 83.6%. In a multiple-marker assay, taking into account the expression of at least 1 of the 5 tumor markers, the sensitivity of the test rose to 95.6%, with a specificity of 66.3% and a general concordance with the histopathologic status of 75.3%. Finally, when at least 2 of 3 markers (maspin, cytokeratin 19 and mammaglobin 1) were expressed, the concordance with either SLN or axillary lymph node status was highest (88.4% and 84.6%, respectively). The high prevalence of positive reverse transcription-polymerase chain reaction assays in histologically uninvolved SLNs, however, may hamper extensive application of these techniques in the clinical setting.

Mandible reconstruction and autogenous frozen bone graft: experimental study on rats.

The aim of this study was to evaluate the biological behaviour of a frozen bone graft in orthotopic and heterotopic sites in the rat. The previous experimental study on this subject was published 25 years ago without sufficient detail about the histology and comparison between the orthotopic and ectopic sites. Therefore, being very important for future clinical application, we decided to evaluate the frozen bone graft using rats. The procedure was performed on two groups of five rats each (Charles River). After wide dissection of the inferior border of the mandible from the surrounding muscle, an inferior segmental resection 4 mm in length was performed, taking care not to fracture the superior part and to maintain mucosal integrity. This segment was placed in liquid nitrogen for two periods of 10 minutes each with a third period to allow it to reach room temperature. In the first group (A), the frozen segment was placed ectopically in a gluteal muscle pocket, and in the second group (B), the frozen bone was fixed in the same position in the same mandible. After 1 month of follow-up, the animals were killed, the bone graft was removed, and histology was performed. Results were consistent in both groups. In group A, the segment was surrounded by strong inflammatory reaction, with no vital cells or bone cells, but some vascular penetration. We concluded that there was no bone deposition and no bone rehabitation. In group B, the initial segment was strongly fixed to the remaining mandible, there was an increase of the macroscopic dimension that paralleled the increase in the dimension of the remaining mandible and the growth of the animal. The cortical part had thinned down, the medullary part presented signs of bone deposition as well as bone resorption and vascular penetration. The periosteum from the adjacent normal mandible was growing and covering the frozen bone graft, offering additional stimulus to the bone deposition. In conclusion, the frozen bone graft acts as a normal bone graft. It needs to be placed in contact with vascularised bone and surrounded by well vascularised soft tissue to allow deposition of new bone. If the frozen graft is placed ectopically, it will be surrounded by chronic inflammatory reaction with no bone deposition.

Life-threatening giant mediastinal goiter: a surgical challenge.

Mediastinal goiter is a well known benign disease, usually resectable through a cervical approach with minimal morbidity and mortality. Only occasionally a median sternotomy or a lateral thoracotomy may be required. The present case is worthy of presentation because of the exceptional dimension of the disease and the surgical challenge that it presented. In a 72-year-old woman a large intrathoracic goiter of the right thorax caused a severe dyspnoea due to an important contralateral mediastinal shift with compression of the lung, superior vena cava system and trachea. At surgical exploration, through a cervico-sternotomic approach, the mediastinal structures dislocation and the strong adherences between the anomalous neovascularized capsula of the mass and the surrounding structures, complicated the surgical dissection. An accidental lesion of the innominate artery required its reimplantation on the ascending aorta. An immense mass, was finally removed and pathological examination revealed a rare case of neovascularized, pseudosarcomatoid capsula among a benign hyperplastic proliferation. In spite of its benign nature, a giant goiter caused a life-threatening compression of the respiratory tract and lung parenchyma in this patient. The dimension of the lesions, the mediastinal anatomy alterations and the severe intraoperative haemorrhage represented major technical difficulties during surgical resection.

Extensive frozen section examination of axillary sentinel nodes to determine selective axillary dissection.

As experience accumulates on the use of sentinel node biopsy in breast cancer, it is becoming clear that the method can reliably predict the state of the axilla and thus be used to decide whether to perform complete axillary dissection. Ongoing controlled trials will soon provide definitive evidence on the latter point. The key issue regarding sentinel node biopsy is pathologic evaluation of the biopsied node, which should be done intraoperatively whenever possible. In our initial experience with a conventional intraoperative frozen section method, the false-negative rate was 19% compared to examination of permanent sections of the biopsied node. We therefore devised a new intraoperative method in which pairs of sections are obtained every 50 mm for the first 15 sections and every 100 mm for any remaining node, which essentially samples the entire node; the method takes about 40 minutes. Sentinel node metastases were found in 119 of 295 (40%) of T1N0 breast cancer patients examined by this new method. This high rate of positivity indicates that the new method is reliable. In all cases, metastases were identified on hematoxylin-eosin (HE)-stained sections, although in 4% of positive cases the HE sections were doubtful, and cytokeratin immunostaining on the adjacent section was useful for confirming malignancy. Of 295 patients, 8 (2.7%) had a negative sentinel node but another axillary node metastasis. In conclusion, we found that extensive intraoperative frozen section examination of sentinel nodes correctly predicts a metastasis-free sentinel node in 95.4% of cases (negative predictive value), it is therefore suitable for identifying patients in whom axillary dissection might be avoided. Immunocytochemical staining for cytokeratins or other epithelial markers may be helpful for reducing the risk of missing micrometastatic foci.

Inhibition of matrix metalloproteinases by over-expression of tissue inhibitor of metalloproteinase-2 inhibits the growth of experimental hemangiomas.

Inhibitors of proteases prevent tumor-associated matrix degradation, affecting tumor growth, angiogenesis and metastasis. Our study was designed to investigate the effect of inhibition of matrix metalloproteinases (MMPs) on the growth of experimental hemangiomas, using the model of murine endothelioma eEnd.1 cells. In nude mice, these cells generate hemangiomas, consisting mostly of host-recruited endothelial cells, whose growth requires the activity of MMPs. In vitro, eEnd.1 cells produce factors that recruit endothelial cells and stimulate them to release MMPs. Over-expression of TIMP-2, following retrovirus-mediated gene transfer, decreased tumor growth in vivo. The infected clone CR1, which produces high levels of TIMP-2 (as assessed by Northern blot, ELISA and reverse zymography), formed slow-growing tumors that did not grow beyond 0.4 g, while clone 1H, which produces little TIMP-2, grew not dissimilarly to mock-infected cells and parental e.End.1 cells. Histologically, control tumors presented the features of cavernous hemangiomas, while CR1 tumors had a more solid pattern, showing foci of apoptotic cells. In vitro, TIMP-2 over-expression had no autocrine anti-proliferative effect on endothelioma cells but reduced their ability to recruit endothelial cells. CR1 cells lacked the capacity of mock-infected or parental eEnd.1 cells to stimulate endothelial cell motility and invasiveness. Antibodies against TIMP-2 restored the ability of CR1 to induce endothelial cell invasion. We conclude that, in this model, genetic increase of TIMP-2 inhibits tumor growth, apparently by affecting the recruitment and organization of host endothelial cells by the transformed cells.

The problem of the accuracy of intraoperative examination of axillary sentinel nodes in breast cancer.

BACKGROUND: Sentinel node (SN) biopsy has become accepted as a reliable method of predicting the state of the axilla in breast cancer. The key issue, however, is the accuracy of the pathological evaluation of the biopsied node, which should be done intraoperatively whenever possible. METHODS: In our initial experience on 192 patients using a conventional intraoperative frozen section method, the false-negative rate was 6.3%, and the negative predictive value was 93.7%. We devised a new and exhaustive intraoperative method, requiring about 40 minutes, in which pairs of sections are taken every 50 microm for the first 15 sections and every 100 microm thereafter, sampling the entire node. Sentinel node metastases were found in 143 of the 376 T1N0 cases examined (38%). RESULTS: Metastases were always identified on hematoxylin and eosin sections, although in 4% of cases, cytokeratin immunostaining on adjacent sections was useful for confirming malignancy. In 233 patients the SNs were disease-free; of these patients, 222 had metastasis-free axillary nodes, and 11 (4.7%) had another metastatic node. CONCLUSION: Extensive intraoperative examination of frozen sentinel nodes correctly predicts an uninvolved axilla in 95.3% of cases (negative predictive value). This method is, therefore, suitable for identifying patients in whom axillary dissection can be avoided.