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

The clinical impact and outcomes of immunohistochemistry-only metastasis in breast cancer

BACKGROUND

Modern surgical and pathological techniques can detect small-volume axillary metastases in breast cancer with unknown clinical significance.

METHODS

A retrospective database review from 1996 through 2004 identified all patients with immunohistochemical (IHC)-only sentinel node (IHC-SN) metastases and compared them with negative controls (Neg-SN).

RESULTS

When comparing the 232 IHC-SN patients with the 252 Neg-SN controls, the IHC-SN patients had larger tumors, more lobular histology, a higher grade, and more HER2/neu positivity. They also received more systemic therapy. With a median follow-up of 5 years, there were no differences in recurrence-free survival or overall survival. In 123 IHC-SN patients treated with axillary dissection (axillary lymph node dissection), 16% had positive non-SLNs. Patients with positive non-SLNs tended to have worse outcomes.

CONCLUSIONS

IHC-only sentinel lymph node (SLN) metastases were associated with worse prognostic features and higher rates of systemic therapy. However, no outcomes differences were noted.

Micrometastatic disease and isolated tumor cells as a predictor for additional breast cancer axillary metastatic burden

BACKGROUND

Our study aims were to investigate breast cancer patients with micrometastases or isolated tumor cells (ITCs) in sentinel lymph nodes (SLNs) to determine the rate of non-SLN metastasis and axillary recurrences, and to compare actual non-SLN metastasis rates with those predicted by the Memorial Sloan-Kettering Cancer Center (MSKCC) nomogram.

METHODS

We identified 116 stage I to III breast cancer patients who underwent sentinel lymph node biopsy and had micrometastases or ITCs (<2-mm deposits). Patients underwent completion axillary lymph node dissection (ALND) (group 1) or had no further axillary surgery (group 2). P < 0.05 was considered statistically significant.

RESULTS

Of 116 patients with micrometastases or ITCs in SLNs, 55 (47%) underwent completion ALND (group 1), and 61 (53%) had no further axillary surgery (group 2). The rate of non-SLN metastases in group 1 patients was 9 (16%) of 55, which was significantly less than that predicted by the MSKCC nomogram (median 30%, P < 0.001). Patient age, race, tumor histology, tumor grade, estrogen receptor/Her-2neu status, and lymphovascular invasion did not differ significantly between group 1 patients with positive non-SLNs and those with negative non-SLNs (P > 0.05 for each), but patients with positive non-SLNs had larger tumors (P < 0.001). No patient in group 1 experienced an axillary recurrence, while only one patient (1.6%) in group 2 experienced axillary recurrence.

CONCLUSIONS

The actual rate of positive non-SLNs for breast cancer patients with SLN micrometastases or ITCs who underwent completion ALND was significantly less than that predicted by the MSKCC nomogram. The rate of axillary recurrence is negligible, regardless of the extent of axillary staging.

Trends in and outcomes from sentinel lymph node biopsy (SLNB) alone vs. SLNB with axillary lymph node dissection for node-positive breast cancer patients: experience from the SEER database

BACKGROUND

Complete axillary lymph node dissection (ALND) after a positive sentinel lymph node biopsy (SLNB) remains the standard practice. As nodal surgery has long been considered a staging procedure without a clear survival benefit, the need for ALND in all patients is debatable. The purpose of this study was to examine differences in survival for patients undergoing SLNB alone versus SLNB with complete ALND.

METHODS

Patients with breast cancer who underwent SLNB and were found to have nodal metastases were identified from the Surveillance, Epidemiology, and End Results database (1998-2004). Clinicopathologic and outcomes data were examined for patients who underwent SLNB alone versus SLNB with ALND.

RESULTS

We identified 26,986 patients with disease-positive lymph nodes; 4,425 (16.4%) underwent SLNB alone, and 22,561 (83.6%) underwent SLNB with ALND. Patients were significantly more likely to undergo SLNB alone if they were older (median 59 years old) or if the tumor was low grade and estrogen receptor positive. From 1998 to 2004, the proportion of patients with micrometastasis in the sentinel lymph nodes who underwent SLNB alone increased from 21.0 to 37.8% (P < 0.001). At a median follow-up of 50 months, there were no statistically significant differences in overall survival (OS) between patients who underwent SLNB alone versus complete ALND.

CONCLUSIONS

There is an increasing trend toward omitting ALND in patients with micrometastatic nodal disease identified by SLNB. Compared with SLNB alone, completion ALND does not seem to be associated with improved survival for breast cancer patients with micrometastasis in the sentinel lymph nodes.

Intraoperative assessment of sentinel lymph nodes in breast cancer

Background

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

Methods

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

Results and conclusion

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

The Extent of Axillary Lymph Node Clearance Required Following Detection of Sentinel Node Micrometastases

Sentinel node (SN) micrometastases are an indication to proceed to axillary clearance. The aim of this study is to determine the extent and level of axillary clearance required for patients with SN micrometastases. All patients with SN micrometastases which were followed by axillary clearances from 1999 to 2007 were identified. Slides were reviewed by a histopathologist to detail characteristics of SN micrometastases including size and site. The SN micrometastases and primary tumor characteristics were correlated with the presence and level of non-SN micrometastases. Fifty patients who had micrometastases followed by axillary clearances were identified. Of those 18% (n = 9) had non-SN metastases.Seven patients had metastases to level I, one patient had metastases to level I and III and one patient had non-SN metastases to level III only. No patient had metastases to level II. Patients with non-SN metastases had very limited number of non-SNs involved (maximum 2 non-SNs). No variable, including site of the micrometastasis, was predictive of non-SN metastases. In patients with SN micrometastases, a limited level I axillary clearance can be justified in view of the low number of additional nodes involved and in particular, the low (4%) rate of spread to level II ⁄ III nodes.

Discordance of intraoperative frozen section analysis with definitive histology of sentinel lymph nodes in breast cancer surgery: complementary axillary lymph node dissection is irrelevant for subsequent systemic therapy

Background

In breast cancer surgery, intraoperative frozen section (FS) analysis of sentinel lymph nodes (SLNs) enables axillary lymph node dissection (ALND) during the same operative procedure. In case of discordance between a “negative” FS analysis and definitive histology, an ALND as a second operation is advocated since additional lymph node metastases may be present. The clinical implications of the subsequent ALND in these patients were evaluated.

Materials and Methods

Between November 2000 and May 2008, 879 consecutive breast cancer patients underwent surgery including sentinel lymph node biopsy (SLNB) with intraoperative FS analysis of 2 central cuts from axillary SLNs. Following fixation and serial sectioning, SLNs were further examined postoperatively with hematoxylin and eosin (H&E) and immunohistochemical techniques. For patients with a discordant FS examination, the effect of the pathology findings of the subsequent ALND specimen on subsequent nonsurgical therapy were evaluated.

Results

FS analysis detected axillary metastases in the SLN(s) in 200 patients (23%), while the definitive pathology examination detected metastases in SLNs in another 151 patients (17%). A complementary ALND was performed in 108 of the 151 patients with discordant FS. Additional tumor positive axillary lymph nodes were found in 17 patients (16%), leading to “upstaging” in 7 (6%). Subsequent nonsurgical treatment was adjusted in 4 patients (4%): all 4 had more extensive locoregional radiotherapy; no patient received additional hormonal and/or chemotherapy.

Conclusion

Discordance between intraoperative FS analysis and definitive histology of SLNs is common. In this selection of patients, a substantial proportion had additional lymph node metastases, but postsurgical treatment was rarely adjusted based on the findings of the complementary ALND.

[Micrometastasis in the sentinel node and axillary lymph node macro-metastasis in breast cancer]

AIM

The study of the sentinel node has made it possible to obtain more comprehensive knowledge about the extent of axillary involvement in breast cancer. It has also decreased the surgical morbidity associated to the surgical examination of the axilla. The systematic use of immunohistochemical staining and molecular biology techniques improves the ability to detect the presence of micrometastasis or isolated tumor cells in a significant number of cases when this is the only sign of the lymph node extension of the disease. The possibility of avoiding complete axillary lymphadenectomy in those patients who are only affected by micrometastasis is proposed because of the low incidence of further involvement of the remaining lymph nodes.

MATERIAL AND METHOD

159 patients diagnosed of stage T1 or T2 breast cancer, in which the sentinel node had been identified by scintigraphy and intraoperative localization, were included in the study. Complete axillary lymphadenectomy was performed when micro- or macrometastases were found in the sentinel node, in order to determine the degree of axillary involvement.

RESULTS

A total of 40 patients (25%) showed infiltration of the sentinel node. This infiltration was only by micrometastasis in 17 of them (10.7%). Of these 17 patients, only 2 (11.8%) showed macro-metastasis in the lymphadenectomy. In the remaining subjects, the final staging reached after the sentinel node study was not modified.

CONCLUSION

It is possible to speculate that, in the future, axillary dissection can be avoided in those patients diagnosed of micrometastasis in the sentinel node, pending the conclusions of the on-going multicenter studies.

Breast cancer prognosis and occult lymph node metastases, isolated tumor cells, and micrometastases

BACKGROUND

The prognostic relevance of isolated tumor cells and micrometastases in lymph nodes from patients with breast cancer has become a major issue since the introduction of the sentinel lymph node procedure. We conducted a systematic review of this issue.

METHODS

Studies published from January 1, 1977, until August 11, 2008, were identified by use of MEDLINE, EMBASE, and the Cochrane Library. A total of 58 studies (total number of patients = 297,533) were included and divided into three categories according to the method for pathological assessment of the lymph nodes: cohort studies with single-section pathological examination of axillary lymph nodes (n = 285,638 patients), occult metastases studies with retrospective examination of negative lymph nodes by step sectioning and/or immunohistochemistry (n = 7740 patients), and sentinel lymph node biopsy studies with intensified work-up of the sentinel but not of the nonsentinel lymph nodes (n = 4155 patients). We used random-effects meta-analyses to calculate pooled estimates of the relative risks (RRs) of 5- and 10-year disease recurrence and death and the multivariably corrected pooled hazard ratio (HR) of overall survival of the cohort studies.

RESULTS

In the cohort studies, the presence (vs the absence) of metastases of 2 mm or less in diameter in axillary lymph nodes was associated with poorer overall survival (pooled HR of death = 1.44, 95% confidence interval [CI] = 1.29 to 1.62). In the occult metastases studies, the presence (vs the absence) of occult metastases was associated with poorer 5-year disease-free survival (pooled RR = 1.55, 95% CI = 1.32 to 1.82) and overall survival (pooled RR = 1.45, 95% CI = 1.11 to 1.88), although these endpoints were not consistently assessed in multivariable analyses. Sentinel lymph node biopsy studies were limited by small patient groups and short follow-up.

CONCLUSION

The presence (vs the absence) of metastases of 2 mm or less in diameter in axillary lymph nodes detected on single-section examination was associated with poorer disease-free and overall survival.

Analysis of predictive tools for further axillary involvement in patients with sentinel lymph node positive small (≤15 mm) invasive breast cancer

Small breast cancers often require different treatment than larger ones. The frequency and predictability of further nodal involvement was evaluated in patients with positive sentinel lymph nodes and breast cancers ≤15 mm by means of 8 different predictive tools. Of 506 patients with such small tumors 138 with positive sentinel nodes underwent axillary dissection and 39 of these had non-sentinel node involvement too. The Stanford nomogram and the micrometastatic nomogram were the predictive tools identifying a small group of patients with low probability of further axillary involvement that might not require completion axillary lymph node dissection. Our data also suggest that the Tenon score can separate subsets of patients with a low and a higher risk of non-sentinel node metastasis. Predictive tools based on multivariate models can help in omitting completion axillary dissection in patients with low risk of non-sentinel lymph node metastasis based on their small tumor size.

Molecular assessment of sentinel lymph node in breast cancer management

Sentinel lymph node biopsy (SLNB) is becoming accepted as standard of care for axillary staging in breast cancer. World Health Organization (WHO) re-classification of axillary metastases into macrometastases, micrometastases and individual tumour cells has highlighted the issues of sampling and further histological examination of the initially negative SLNB. Molecular detection of metastatic breast cancer cells in lymph nodes is now available as a commercial kit for intraoperative use and can resolve the sampling issue. Semiquantitative assessment of axillary lymph node tumour burden can now be made using two separate technologies (histology and reverse transcriptase-polymerase chain reaction). The clinical implications of low metastatic axillary lymph node tumour burden are not clear, and future trials need to include molecular data. The consequences of the availability of molecular assessment are reviewed.

Sentinel node biopsy in breast cancer: five years experience from Denmark

INTRODUCTION

Danish experience from the first five years with sentinel lymph node biopsy (SLNB) as a routine staging procedure in early breast cancer is reported.

METHODS

During the period January 1, 2002 to December 31, 2006, 14 923 patients were diagnosed at Danish breast surgical centers certified for the sentinel node method. SLNB was performed in 8 338 patients (55.9%). The fraction increased steadily from 43% in 2002 to 67% in 2006. The median follow-up was 1.7 year (range 0-5.2 years).

RESULTS

Patients staged with SLNB were younger, had more often BCS, had smaller tumor size, were more often hormone receptor positive, and had lower grade, than patients staged with lymph node dissection (ALND). Blue dye and radio colloid were used in combination in 82%. Lymphoscintigraphy was performed in 61%, and frozen section was performed in 87%. Originally, peritumoral injection of tracer was most often used, but the recommendations have changed, and in 2006 90% of cases had sub-or periareolar injection of radioactive tracer. In the sentinel nodes 25% had macrometastases, 17% micrometastases only, and 3.2% isolated tumor cells only (ITC). ALND was performed in 2 714 patients, whose lymph node classification by SN was known. In the group of 1 563 patients with macrometastases in SN, 45% had non-sentinel node metastases, and in the group of 942 patients with micrometastases only, 23% had more positive nodes. Regional lymph node metastases were found in 15% with ITC in sentinel nodes. Lymph node recurrence among node negative patients was observed more often after staging by SLNB (0.5%) than after ALND (0.2%, p =0.04).

CONCLUSION

Two thirds of breast cancer patients can be safely staged with the sentinel node technique, half of these will need no further axillary surgery. The loco-regional control in node negative patients classified by SLNB is high, but seems not quite comparable to what is seen after ALND.

Survey of ASCO members on management of sentinel node micrometastases in breast cancer: variation in treatment recommendations according to specialty

BACKGROUND

American Society of Clinical Oncology (ASCO) guidelines recommend axillary dissection (ALND) as the primary treatment for sentinel node micrometastases (SNMM) in breast cancer. We hypothesized that variation exists in adherence to these guidelines and management of SNMM as a result of the medical specialty of the treating physician.

METHODS

A questionnaire was e-mailed to 2511 active members of ASCO who specialize in breast cancer and who are board certified in surgery, medical oncology, or radiation oncology. Questions covered treatment of SNMM and factors influencing clinical decisions. Survey responses were analyzed by the Kruskal-Wallis and Fisher's exact test.

RESULTS

Of 612 questionnaires viewed by recipients, 537 (88%) were completed by 382 medical oncologists, 100 surgeons, and 55 radiation oncologists. Most (98.5%) regarded SNMM as clinically important. Unexpectedly, ALND for SNMM was recommended by only 23% of surgeons, 23% of medical oncologists, and 15% of radiation oncologists (no statistically significant intergroup difference). Factors identified as important in selecting patients for ALND were tumor size, age, tumor grade, lymphovascular invasion, and size of metastases. Most respondents in each specialty (89% overall) would consider adjuvant chemotherapy for primary tumors <1 cm if SNMM were present. Tumor size, age, size of metastases, estrogen receptor/progesterone receptor status, HER-2 neu status, and gene expression profile would influence this decision. Radiation oncologists (76%) were more likely than medical oncologists (57%) or surgeons (47%) to consider axillary radiation instead of ALND for SNMM (P = 0.0021).

CONCLUSIONS

Guidelines recommending ALND for SNMM are not being followed by most of the ASCO members we surveyed.

Identification and biologic significance of micrometastases in axillary lymph nodes in patients with invasive breast cancer

CONTEXT

The presence or absence of metastases in axillary lymph nodes is one of the most important prognostic factors for patients with breast cancer. During the past decade sentinel lymph node (SLN) biopsy has been increasingly adopted as a minimally invasive staging alternative to complete axillary node dissection.

OBJECTIVE

Sentinel lymph nodes are more likely to contain metastases than non-SLNs. In routine clinical practice SLNs are assessed by diverse methodologies including multiple sectioning, immunohistochemical staining, and molecular diagnostic tests. Despite the lack of standard histopathologic protocols during the years detailed evaluation of SLNs has resulted in an increased detection of small (micro) metastases.

DATA SOURCES

Breast cancer with micrometastases constitutes a heterogenous group of tumors with variable clinical outcome regarding the risk of additional metastases in the remaining axillary lymph nodes and to patients' survival.

CONCLUSION

The clinical significance of micrometastases has been subject to great controversy in patients with breast cancer. In this review we highlight controversies regarding micrometastases especially in relation to SLNs.

Multidisciplinary care for patients with breast cancer

The care of patients with breast cancer has become increasingly complex with advancements in diagnostic modalities, surgical approaches, and adjuvant treatments. A multidisciplinary approach to breast cancer care is essential to the successful integration of available therapies. This article addresses the key components of multidisciplinary breast cancer care, with a special emphasis on new and emerging approaches over the past 10 years in the fields of diagnostics, surgery, radiation, medical oncology, and plastic surgery.

Sentinel node biopsy in breast cancer patients with large or multifocal tumors

BACKGROUND

The axillary recurrence (AR) rate after negative sentinel node biopsy (SNB) in patients with high risk of axillary metastases is largely unknown. The aim of this study was to analyze the risk factors for isolated AR after negative SNB with special interest in large or multifocal tumors.

METHODS

A prospective SNB registry was analyzed for 2,408 invasive breast cancer patients operated between 2001 and 2007. No axillary clearance was performed in 1,309 cases with a negative SNB, including 1,138 small unifocal tumors, 121 small multifocal tumors, 48 large unifocal tumors, and 2 large multifocal tumors.

RESULTS

Six (0.5%) isolated AR were observed during a median follow-up of 43 months. Four (0.4%) patients with small unifocal tumors and two (1.6%) with small multifocal tumors had isolated AR (p = 0.179). None of the patients with large unifocal or multifocal tumors had isolated AR. Instead of tumor size and multifocality, estrogen receptor negativity (p < 0.001), nuclear grade III (p < 0.001), Her-2 status (p = 0.002), no radiotherapy (p = 0.005), and mastectomy (p = 0.005) were found to be associated with AR.

CONCLUSIONS

A remarkable proportion of patients with large unifocal tumors and small multifocal tumors may avoid unnecessary AC due to tumor negative SNB, without an excessive risk of AR.

[Sentinel node biopsy in breast cancer: pathological analysis and interpretation]

This overview examines how the introduction of sentinel lymph node biopsy (SLNB) has changed the pathological staging of breast cancer. The more intensive analysis of the sentinel lymph nodes (gross slicing, step sections, immunohistological or molecular analysis) has lead to stage shifting in breast cancer. Regarding the rate of up-staging by positive results of SLNB, there are significant differences between institutes, some method-related, some related to the interpretation of results. Methodological differences should be reduced by means of reliable guidelines with the goal of systematically identifying metastases of a particular size (a macrometastasis over 2 mm being the minimum criterion). The next review of the TNM classification should result in a reduction in interobserver variability as a result of better definitions of staging categories for isolated tumor cells and micrometastases. In addition, a staging category is expected for metastases which have been identified by calibrated quantitative molecular tests only and which are larger than isolated tumors. Even in settings where nodal staging by SLNB is based on molecular tests at least a proportion of the lymph node should be investigated histologically.

Prognostic implications of isolated tumor cells and micrometastases in sentinel nodes of patients with invasive breast cancer: 10-year analysis of patients enrolled in the prospective East Carolina University/Anne Arundel Medical Center Sentinel Node Multicenter Study

BACKGROUND

Sentinel lymph node biopsy (SLNB) is a more sensitive and accurate nodal staging procedure than axillary lymph node dissection (ALND). Because of increased pathologic evaluation in the sentinel node era, more nodal micrometastases (MIC) (> 0.2 mm to 2 mm) and isolated tumor cells (ITC; < or = 0.2 mm) have been identified. We present the 10-year analysis of our prospective SLN study, focusing on regional axillary node status and distant metastases in patients with nodal ITC and MIC.

STUDY DESIGN

From 1996 to 2005, breast cancer patients were enrolled in an Institutional Review Board-approved, multicenter study. SLNs were examined at multiple levels by hematoxylin and eosin; most (85%) hematoxylin and eosin-negative SLNs were also examined by cytokeratin immunohistochemistry. Data from 1,259 patients with invasive breast cancer and in whom an SLN was found were reviewed for this analysis.

RESULTS

Of the 1,259 patients, 893 (71%) had negative SLNs, 25 (2%) had ITCs, 57 (5%) had MIC, and 284 (23%) had positive SLNs. None of the 13 patients with ITCs who underwent an ALND had additional positive nodes, compared with 27% (11 of 41) of patients with MIC. At a mean followup of 4.9 years, the distant recurrence rates for SLN-negative, ITC, MIC, and SLN-positive groups were 6%, 8%, 14%, and 21%, respectively. The presence of MIC in the SLN was associated with a significantly shorter disease-free interval than was SLN negativity (p < 0.02 by Cox regression model).

CONCLUSIONS

This prospective breast cancer study found that sentinel node MIC, but not ITCs, were associated with additional positive nodes and with distant recurrence. These data suggest that ALND may be unnecessary in patients with ITCs. But ALND and more aggressive adjuvant therapy should be considered in patients with SLN micrometastases.

False-negative sentinel lymph node biopsy

BACKGROUND

The clinical significance of false-negative axillary sentinel lymph node (SLN) biopsy has yet to be established. The aim of this study was to assess the axillary recurrence rate and false-negative rate, to identify prognostic factors and to monitor survival.

METHODS

A prospective registry of sentinel lymph node biopsy (SLNB) procedures performed between 1998 and 2004 was analysed. All nodes retrieved were examined by haematoxylin and eosin and immunohistochemical staining. Further surgical treatment was performed only for positive SLNs. Adjuvant treatment was given according to Dutch guidelines.

RESULTS

Of 592 patients, 392 had a negative SLNB. After a median follow-up of 65 months, 11 patients developed axillary recurrence (2.8 per cent). Ten of these patients were primarily treated by simple mastectomy and therefore had no external-beam radiation therapy; no further prognostic factors could be identified. The false-negative rate was 6.9 per cent. The median time from SLNB to detection of the axillary recurrence was 27 months. The median follow-up after recurrence was 35 months, and one patient developed systemic disease. Pathology revision revealed two previously undetected micrometastases.

CONCLUSION

Axillary recurrence and false-negative rates after SLNB increase with longer follow-up.

Non-sentinel lymph node metastases associated with isolated breast cancer cells in the sentinel node

There are many reports on the frequency of non-sentinel lymph node involvement when isolated tumor cells are found in the sentinel node, but results and recommendations for the use of an axillary lymph node dissection differ among studies. This systematic review was conducted to give an overview of this issue and to provide recommendations for the use of an axillary lymph node dissection in these patients. We searched Medline, Embase, and Cochrane databases from January 1, 2002, through November 27, 2007, for articles on patients with invasive breast cancer who had isolated tumor cells in the sentinel lymph node (according to the sixth edition of the Cancer Staging Manual of the American Joint Committee on Cancer) and who also underwent axillary lymph node dissection. Of 411 selected articles, 29 (including 836 patients) were included in this review. These 29 studies were heterogeneous, reporting a wide range of non-sentinel lymph node involvement (defined as the presence of isolated tumor cells or micro- or macrometastases) associated with isolated tumor cells in the sentinel lymph node, with an overall pooled risk for such involvement of 12.3% (95% confidence interval = 9.5% to 15.7%). This pooled risk estimate was marginally higher than the risk of a false-negative sentinel lymph node biopsy examination (ie, 7%-8%) but marginally lower than the risk of non-sentinel lymph node metastases in patients with micrometastases (ie, approximately 20%) who are currently eligible for an axillary lymph node dissection. Because 36 (64%) of the 56 patients with isolated tumor cells in their sentinel lymph node also had non-sentinel lymph node macrometastases, those patients with isolated tumor cells in the sentinel lymph node without other indications for adjuvant systemic therapy might be candidates for axillary lymph node dissection.

Variations in sentinel node isolated tumour cells/micrometastasis and non-sentinel node involvement rates according to different interpretations of the TNM definitions

Breast cancers with nodal isolated tumour cells (ITC) and micrometastases are categorised as node-negative and node-positive, respectively, in the tumour node metastasis (TNM) classification. Two recently published interpretations of the TNM definitions were applied to cases of low-volume sentinel lymph node (SLN) involvement and their corresponding non-SLNs for reclassification as micrometastasis or ITC. Of the 517 cases reviewed, 82 had ITC and 435 had micrometastasis on the basis of one classification, and the number of ITC increased to 207 with 310 micrometastases on the basis of the other. Approximately 24% of the cases were discordantly categorised. The rates of non-SLN metastases associated with SLN ITCs were 8.5% and 13.5%, respectively. Although the second interpretation of low-volume nodal stage categories has better reproducibility, it may underestimate the rate of non-SLN involvement. The TNM definitions of low-volume nodal metastases need to be better formulated and supplemented with visual information in the form of multiple sample images.

The number of positive nodes and the ratio of positive to excised nodes are significant predictors of survival in women with micrometastatic node-positive breast cancer

BACKGROUND

To evaluate the prognostic impact of the number of positive nodes and the lymph node ratio (LNR) of positive to excised nodes on survival in women diagnosed with nodal micrometastatic breast cancer before the era of widespread sentinel lymph node biopsy.

METHODS

Subjects were 62,551 women identified by the Surveillance Epidemiology and End Results database, diagnosed with pT1-2pN0-1 breast cancer between 1988 and 1997. Kaplan-Meier breast cancer-specific survival (BCSS) and overall survival (OS) were compared between three cohorts: node-negative (pN0, n=57,980) nodal micrometastasis all <or=2mm (pNmic, N=1818), and macroscopic nodal metastasis >2mm but <2 cm (pNmac, n=2753). Nodal subgroups were examined by the number of positive nodes (1-3 versus >or= 4) and the LNR (<or=0.25 versus >0.25).

RESULTS

Median follow-up was 7.3 yr. Ten-year BCSS and OS in pNmic breast cancer were significantly lower compared to pN0 disease (BCSS 82.3% versus 91.9%, p<0.001 and OS 68.1% versus 75.7%, p<0.001). BCSS and OS with pNmic disease progressively declined with increasing number of positive nodes and increasing LNR. OS with pNmic was similar to pNmac disease when matched by the number of positive nodes and by the LNR. Both pN-based and LNR-based classifications were significantly prognostic of BCSS and OS on Cox regression multivariate analysis.

CONCLUSION

Nodal micrometastasis is associated with poorer survival compared to pN0 disease. Mortality hazards with nodal micrometastasis increased with increasing number of positive nodes and increasing LNR. The number of positive nodes and the LNR should be considered in risk estimates for patients with nodal micrometastatic breast cancer.

Immunohistochemistry on frozen section of sentinel lymph nodes in breast cancer with improved morphology and blocking of endogenous peroxidase

Sentinel lymph node biopsy in the management of patients with breast cancer is the clinical practice. Peroperative examination means that more patients can be treated in a 1-step procedure. The addition of immunohistochemistry to frozen section slides improves the detection rate of especially micrometastasis. We present a novel method for immunohistochemical staining on a frozen section material that gives better morphology and blocks endogenous peroxidase sufficiently.

Strategies for optimizing pathologic staging of sentinel lymph nodes in breast cancer patients

Due to the extensive pathologic evaluation of the sentinel lymph node (SLN), micrometastases are frequently observed. If micrometastases are clinically relevant, the histopathologic examination of SLNs should be sensitive enough to detect them. The probability of detecting micrometastases was calculated when examining the SLN according to the current Dutch pathology protocol and strategies evaluated to optimize the chance of detection. The dimensions of 20 consecutive axillary SLNs in patients with cT1-2N0 breast cancer were measured. In a mathematical model, the probability of detecting micrometastases in a SLN was calculated. Similarly, strategies to optimize the probability of detecting micrometastases were explored. When applying the pathology guidelines, the calculated probability to detect a micrometastasis was 18% for a 200-microm micrometastasis and 69% for a 2.0-mm metastasis in a median sized SLN. To detect the smallest micrometastasis in a median-sized SLN with a 95% probability, the interval between the sections must be decreased to 200 microm, and 20 levels from both halves must be examined. Given a prognostic significance of micrometastases, our current pathology guidelines are not sensitive enough. The number of sections should be increased, while the interval between cuts should be no more than 200 microm.

A model for predicting non-sentinel lymph node metastatic disease when the sentinel lymph node is positive

BACKGROUND

Women with axillary sentinel lymph node (SLN)-positive breast cancer usually undergo completion axillary lymph node dissection (ALND). However, not all patients with positive SLNs have further axillary nodal disease. Therefore, in the patients with low risk of further disease, completion ALND could be avoided. The Memorial Sloan-Kettering Cancer Center (MSKCC) developed a nomogram to estimate the risk of non-SLN disease. This study critically appraised the nomogram and refined the model to improve predictive accuracy.

METHODS

The MSKCC nomogram was applied to 118 patients with a positive axillary SLN biopsy who subsequently had completion ALND. Predictive accuracy was assessed by calculating the area under the receiver-operator characteristic (ROC) curve. A further predictive model was developed using more detailed pathological information. Backward stepwise multiple logistic regression was used to develop the predictive model for further axillary lymph node disease. This was then converted to a probability score. After k-fold cross-validation within the data, an inverse variance weighted mean ROC curve and area below the ROC curve was calculated.

RESULTS

The MSKCC nomogram had an area under the ROC curve of 68 per cent. The revised predictive model showed the weighted mean area under the ROC curve to be 84 per cent.

CONCLUSION

The modified predictive model, which incorporated size of SLN metastasis, improved predictive accuracy, although further testing on an independent data set is desirable.

Management of the axilla in women with breast cancer: current clinical practice and a new selective targeted approach

BACKGROUND

Axillary nodal status is the most important prognostic factor for patients with breast cancer. Clinical assessment and imaging modalities are not always reliable. Surgical removal and histopathological examination of axillary lymph nodes remain essential methods of staging the axilla. However, the optimal management of the axilla remains uncertain.

METHODS

We performed Medline searches to identify relevant systematic reviews, meta-analysis, and nonrandomized and randomized controlled trials for the past 5 years (up to December 2007), as well as important historical articles and clinical guidelines relating to management of the axilla in women with breast cancer.

RESULTS

Axillary lymph node dissection (ALND) has been the standard surgical approach for many years. It is, however, associated with marked morbidity; survival benefit remains uncertain. Axillary node sampling, widely practiced in the United Kingdom, is a reliable alternative procedure in staging the axilla, with less morbidity. Sentinel lymph node biopsy (SLNB) has become an accurate method for staging the axilla in women with operable, clinically node-negative breast cancer. SLNB alone appears to be a safe and acceptable procedure for patients with uninvolved SLNs. Completion ALND or axillary radiotherapy remains the standard treatment for patients with tumor-involved SLNs. SLNB is associated with less morbidity than ALND. However, long-term follow-up and therapeutic outcomes are being awaited from randomized controlled trials.

CONCLUSIONS

Several procedures are available for staging and treating the axilla. A tailored surgical approach, with careful assessment of risk-benefit and patient preference, is guiding the evolving modern management of the axilla for women with breast cancer.

New models and online calculator for predicting non-sentinel lymph node status in sentinel lymph node positive breast cancer patients

Background

Current practice is to perform a completion axillary lymph node dissection (ALND) for breast cancer patients with tumor-involved sentinel lymph nodes (SLNs), although fewer than half will have non-sentinel node (NSLN) metastasis. Our goal was to develop new models to quantify the risk of NSLN metastasis in SLN-positive patients and to compare predictive capabilities to another widely used model.

Methods

We constructed three models to predict NSLN status: recursive partitioning with receiver operating characteristic curves (RP-ROC), boosted Classification and Regression Trees (CART), and multivariate logistic regression (MLR) informed by CART. Data were compiled from a multicenter Northern California and Oregon database of 784 patients who prospectively underwent SLN biopsy and completion ALND. We compared the predictive abilities of our best model and the Memorial Sloan-Kettering Breast Cancer Nomogram (Nomogram) in our dataset and an independent dataset from Northwestern University.

Results

285 patients had positive SLNs, of which 213 had known angiolymphatic invasion status and 171 had complete pathologic data including hormone receptor status. 264 (93%) patients had limited SLN disease (micrometastasis, 70%, or isolated tumor cells, 23%). 101 (35%) of all SLN-positive patients had tumor-involved NSLNs. Three variables (tumor size, angiolymphatic invasion, and SLN metastasis size) predicted risk in all our models. RP-ROC and boosted CART stratified patients into four risk levels. MLR informed by CART was most accurate. Using two composite predictors calculated from three variables, MLR informed by CART was more accurate than the Nomogram computed using eight predictors. In our dataset, area under ROC curve (AUC) was 0.83/0.85 for MLR (n = 213/n = 171) and 0.77 for Nomogram (n = 171). When applied to an independent dataset (n = 77), AUC was 0.74 for our model and 0.62 for Nomogram. The composite predictors in our model were the product of angiolymphatic invasion and size of SLN metastasis, and the product of tumor size and square of SLN metastasis size.

Conclusion

We present a new model developed from a community-based SLN database that uses only three rather than eight variables to achieve higher accuracy than the Nomogram for predicting NSLN status in two different datasets.