Axillary lymph-node dissection for positive sentinel nodes in breast cancer patients

A novel nomogram for decision-making assistance on exemption of axillary lymph node dissection in T1–2 breast cancer with only one sentinel lymph node metastasis

Background

T1–2 breast cancer patients with only one sentinel lymph node (SLN) metastasis have an extremely low non-SLN (NSLN) metastatic rate and are favorable for axillary lymph node dissection (ALND) exemption. This study aimed to construct a nomogram-based preoperative prediction model of NSLN metastasis for such patients, thereby assisting in preoperatively selecting proper surgical procedures.

Methods

A total of 729 T1–2 breast cancer patients with only one SLN metastasis undergoing sentinel lymph node biopsy and ALND were retrospectively selected from Harbin Medical University Cancer Hospital between January 2013 and December 2020, followed by random assignment into training (n=467) and validation cohorts (n=262). A nomogram-based prediction model for NSLN metastasis risk was constructed by incorporating the independent predictors of NSLN metastasis identified from multivariate logistic regression analysis in the training cohort. The performance of the nomogram was evaluated by the calibration curve and the receiver operating characteristic (ROC) curve. Finally, decision curve analysis (DCA) was used to determine the clinical utility of the nomogram.

Results

Overall, 160 (21.9%) patients had NSLN metastases. Multivariate analysis in the training cohort revealed that the number of negative SLNs (OR: 0.98), location of primary tumor (OR: 2.34), tumor size (OR: 3.15), and lymph-vascular invasion (OR: 1.61) were independent predictors of NSLN metastasis. The incorporation of four independent predictors into a nomogram-based preoperative estimation of NSLN metastasis demonstrated a satisfactory discriminative capacity, with a C-index and area under the ROC curve of 0.740 and 0.689 in the training and validation cohorts, respectively. The calibration curve showed good agreement between actual and predicted NSLN metastasis risks. Finally, DCA revealed the clinical utility of the nomogram.

Conclusion

The nomogram showed a satisfactory discriminative capacity of NSLN metastasis risk in T1–2 breast cancer patients with only one SLN metastasis, and it could be used to preoperatively estimate NSLN metastasis risk, thereby facilitating in precise clinical decision-making on the selective exemption of ALND in such patients.

Treatment of sentinel node-positive breast cancer

Sentinel node biopsy has become well accepted as a minimally invasive means of accurately staging the axilla in breast cancer patients. Patients with metastases in the sentinel node(s) have traditionally proceeded to completion of axillary node dissection, whereas patients who are node negative can be spared the morbidity of this procedure. Recently, there has been some debate as to what constitutes node-positive disease and whether patients with metastasis in the sentinel node(s) require completion axillary dissection. This review addresses the controversies regarding the management of sentinel node-positive breast cancer patients.

[Adjuvant treatments in breast cancer: interest of completion of axillary dissection in case of micrometastases or isolated tumor cells in sentinel lymph node]

Prognostic signification of micrometastases ou isolated tumor cells (ITC) has not yet been clearly precised. Management of the axilla in case of micrometastases or ITC depends on the local pratices: no surgical completion or axillary lymph node dissection (ALND). Axillary lymph node status is the most important prognostic factor in patients with breast cancer; morbidity of ALND is now well known whereas its therapeutic benefit has not been demonstrated. This study is based on a retrospective database of 1375 patients who underwent sentinel node (SN) biopsy for breast cancer. In case of micrometastase or ITC in SN with completion axillary dissection, we examined if non-sentinel lymph node status has changed the indications of adjuvant treatments (chimiotherapy or radiotherapy). The results of our study show that non-sentinel lymph node status modify systemic therapy for a very few patients (less than 4% concerning chimiotherapy and less than 15% concerning radiotherapy).

Prediction of non-sentinel lymph node status in breast cancer patients with sentinel lymph node metastases: evaluation of the tenon score

INTRODUCTION

Current guidelines recommend completion axillary lymph node dissection (cALND) in case of a sentinel lymph node (SLN) metastasis larger than 0.2 mm. However, in 50%-65% of these patients, the non-SLNs contain no further metastases and cALND provides no benefit. Several nomograms and scoring systems have been suggested to predict the risk of metastases in non-SLNs. We have evaluated the Tenon score.

PATIENTS AND METHODS

In a retrospective review of the Swedish Sentinel Node Multicentre Cohort Study, risk factors for additional metastases were analysed in 869 SLN-positive patients who underwent cALND, using uni- and multivariate logistic regression models. A receiver operating characteristic (ROC) curve was drawn on the basis of the sensitivity and specificity of the Tenon score, and the area under the curve (AUC) was calculated.

RESULTS

Non-SLN metastases were identified in 270/869 (31.1%) patients. Tumour size and grade, SLN status and ratio between number of positive SLNs and total number of SLNs were significantly associated with non-SLN status in multivariate analyses. The area under the curve for the Tenon score was 0.65 (95% CI 0.61-0.69). In 102 patients with a primary tumour <2 cm, Elston grade 1-2 and SLN metastases ≤2 mm, the risk of non SLN metastasis was less than 10%.

CONCLUSION

The Tenon score performed inadequately in our material and we could, based on tumour and SLN characteristics, only define a very small group of patients in which negative non-sentinel nodes could be predicted.

Sentinel lymph node micrometastasis in human breast cancer: an update

INTRODUCTION

The advent of sentinel lymph node biopsy (SLNB) and advances in histopathological and molecular analysis techniques have been associated with an increase in micrometastasis (MM) detection rate. However, the clinical significance of sentinel lymph node micrometastasis (SLN MM) continues to be a subject of much debate. In this article we review the literature concerning SLN MM, with particular emphasis on the prognostic significance of SLN MM. The controversies regarding histopathological assessment, clinical relevance and management implications are also discussed.

METHODS

Literature review facilitated by Medline and PubMed databases. Cross referencing of the obtained articles was used to identify other relevant studies.

RESULTS

Published studies have reported divergent and rather conflicting results regarding the clinical significance and implications of axillary lymph node (ALN) MM in general and SLN MM in particular. Some earlier studies demonstrated no associations, however most recent studies have found SLN MM to be an indicator of poorer prognosis and to be associated with non-SLN involvement. The use of adjuvant chemotherapy and/or hormonal manipulation therapy is associated with an improved survival in patients with SLN MM. Complete ALND may be safely omitted provided that adjuvant systemic therapy recommendations are equal to patients with node-positive disease. However, optimal management of SLN MM is yet to conclude. Furthermore, the identification of MM remains largely dependent on the analytical technique employed and the use of immunohistochemistry (IHC) increases the detection rate of SLN MM. Discrepancies in the histopathological interpretation of TNM classification of SLN tumour burden do exist. Published studies were non-randomized and have significant limitations including a small sample size, limited follow-up period, and lack of standardization and reproducibility of pathological examination of the SLN.

CONCLUSION

Patients with SLN MM have a poorer prognosis than those who are SLN negative. Therapeutic recommendations regarding patients with SLN MM should be taken in the context of multidisciplinary team setting and in selected cases of SLN MM, complete ALND may be safely omitted. A better reproducibility of pathological interpretation of the TNM classification is required so that future therapeutic guidelines can be applied without confusion.

Meta-analysis of predictive factors for non-sentinel lymph node metastases in breast cancer patients with a positive SLN

AIMS

A meta-analysis was performed to identify the clinicopathological variables most predictive of non-sentinel node (NSN) metastases when the sentinel node is positive.

METHODS

A Medline search was conducted that ultimately identified 56 candidate studies. Original data were abstracted from each study and used to calculate odds ratios. The random-effects model was used to combine odds ratios to determine the strength of the associations.

FINDINGS

The 8 individual characteristics found to be significantly associated with the highest likelihood (odds ratio >2) of NSN metastases are SLN metastases >2mm in size, extracapsular extension in the SLN, >1 positive SLN, ≤1 negative SLN, tumour size >2cm, ratio of positive sentinel nodes >50% and lymphovascular invasion in the primary tumour. The histological method of detection, which is associated with the size of metastases, had a correspondingly high odds ratio.

CONCLUSIONS

We identified 8 factors predictive of NSN metastases that should be recorded and evaluated routinely in SLN databases. These factors should be included in a predictive model that is generally applicable among different populations.

Pathologic evaluation of axillary dissection specimens following unexpected identification of tumor within sentinel lymph nodes

CONTEXT

Axillary lymph node dissection has been the standard of care after identification of a positive sentinel lymph node for breast cancer patients.

OBJECTIVE

To determine the likelihood of non-sentinel lymph node involvement for patients with negative sentinel node by frozen section, who are subsequently found to have tumor cells in the sentinel node by permanent section levels and/or cytokeratin immunohistochemistry.

DESIGN

One hundred three patients with invasive breast cancer exhibiting negative frozen section evaluation of their sentinel node, but later found to have isolated tumor cells (n  =  46), micrometastasis (n  =  46), or metastases (n  =  11) in their sentinel node by permanent sections or immunohistochemistry, were enrolled in this prospective cohort study and underwent completion axillary dissection.

RESULTS

Six of 46 patients (13%) with isolated tumor cells in their sentinel node, 15 of 46 patients (33%) with micrometastasis in their sentinel node, and 2 of 11 patients (18%) with metastasis in their sentinel node had additional findings in the nonsentinel nodes. These findings resulted in a pathologic stage change in 2 patients. Predictors of positive nonsentinel nodes were 2 or more positive sentinel nodes (P  =  .002), sentinel nodes with micrometastasis versus isolated tumor cells (P  =  .03), and those with angiolymphatic invasion (P  =  .04).

CONCLUSIONS

Our findings lend support to axillary node dissection for patients with micrometastasis or metastasis in their sentinel nodes. However, studies with clinical follow-up are needed to determine whether axillary node dissection is necessary for patients with isolated tumor cells in sentinel nodes.

Comparison of three mathematical models for predicting the risk of additional axillary nodal metastases after positive sentinel lymph node biopsy in early breast cancer

Background

Women with breast cancer and a positive axillary sentinel lymph node (SLN) are recommended to undergo complete axillary lymph node dissection; however, further nodal disease is not always present. Mathematical models have been constructed to determine the risk of metastatic disease; three of these were evaluated independently.

Methods

Data from 108 women with breast cancer who had a positive SLN biopsy and completion axillary lymph node dissection were used. Measurements of additional parameters over those usually determined (such as size of SLN metastasis) were assessed under the supervision of two pathologists. These data were used to determine the predicted risk of non-SLN metastases using three mathematical models (from Memorial Sloan-Kettering Cancer Center (MSKCC), Cambridge University and Stanford University) and a comparison made with the observed findings. Analyses were made using the area under the receiver operating characteristic (ROC) curve (AUC).

Results

Some 53 (49·1 per cent) of 108 patients had a positive non-sentinel axillary lymph node metastasis. The AUC values were 0·63, 0·72 and 0·67 for the MSKCC, Cambridge and Stanford nomograms respectively.

Conclusion

This independent comparison found no significant difference between the models, although the Cambridge model had the advantage of requiring fewer measurements with a more accurate predictive performance.

The MSKCC nomogram for prediction the likelihood of non-sentinel node involvement in a German breast cancer population

OBJECTIVE

To assess whether the Memorial Sloan Kettering Cancer Center (MSKCC) nomogram for prediction of NSLN metastasis is useful in a German breast cancer population and whether the characteristics of the breast tumor and the sentinel lymph node (SLN) are able to predict the likelihood of non-sentinel lymph node (NSLN) metastasis.

METHODS

A total of 545 patients with primary breast cancer and SLN examination were evaluated. The MSKCC nomogram was applied to 98 patients with a positive SLN who subsequently had completion axillary lymph node dissection (ALND). Predictive accuracy was assessed by calculating the area under the receiver-operator characteristic (ROC) curve. The collective was evaluated by correlating the prevalence of NSLN and SLN metastasis to pathological features.

RESULTS

The MSKCC nomogram achieved a ROC of 0.58 indicating a bad accuracy of the nomogram. Tumor size, histology, lymphovascular infiltration, multifocality, Her-2-neu positivity, and nuclear grade correlated with the probability of SLN metastasis. Histology and primary tumor localization correlated significantly with the probability of NSLN metastasis.

CONCLUSIONS

The MSKCC nomogram did not provide a reliable predictive model in our study population. However, the likelihood of SLN metastasis correlated with the presumed risk factors and no obvious differences between the MSKCC population and our population could be seen. In order to achieve interinstitutional reproducibility, standardization of surgical procedure and of the pathological assessment of the SLN is desirable.

Validation of clinical prediction rules for a low probability of nonsentinel and extensive lymph node involvement in breast cancer patients

BACKGROUND

Two recently developed clinical prediction rules aim to anticipate the lack of nonsentinel lymph node metastases and the involvement of less than 4 lymph nodes in breast cancer patients with positive sentinel lymph nodes (SLNs).

METHODS

The University of Louisville Breast SLN Study clinical prediction rules were validated on an independent set of SLN-positive patients with tumors < or = 15 mm.

RESULTS

The data on 475 and 473 patients, respectively, were used for the validation. The areas under the receiver operating characteristic curves were similar to the originals for both predictive tools (.70 and .76). The lowest score of 1 identified 5 of 7 patients with disease limited to the SLNs and 161 of 165 as having less than 4 involved lymph nodes.

CONCLUSIONS

A subset of patients with SLN-only involvement and less than 4 metastatic lymph nodes can probably be identified by means of the Louisville clinical prediction rules, but prediction of the lack of non-SLN metastasis seems less reliable.

Use of immunohistochemistry in diagnosis of breast epithelial lesions

In recent years, the use of immunohistochemistry (IHC) in breast pathology has increased tremendously. It is not because the new genre of breast pathologists are less well trained than their "experienced" counterparts; it is mainly because of the demands of more accurate and precise diagnoses, identification of new entities and availability of novel antibodies. The main purpose of this review is to discuss the use of best available antibodies in diagnoses of breast epithelial lesions. The following items are discussed: assessment of invasion, IHC in papillary lesions, identification of breast tumor subtypes, IHC in proliferative breast lesions, assessment of lymphatic space invasion, diagnosis of metaplastic breast carcinoma, IHC in Paget disease, use of cytokeratins in sentinel lymph node assessment, and diagnosis of breast carcinoma at metastatic sites. Because the main focus of this review is on diagnosis, receptor studies on breast carcinoma are briefly discussed and only a few general comments are made.

Expression of retinoblastoma protein in breast cancer metastases to sentinel nodes: evaluation of its role as a marker for the presence of metastases in non-sentinel axillary nodes, and comparison to p16INK4a

The aim of this study was to evaluate the role of retinoblastoma protein (pRb), alone and in combination with p16, as a predictive marker for metastases in non-sentinel nodes in cases where the sentinel node showed metastatic breast carcinoma. Paraffin blocks of lymph nodes from 48 patients with metastatic breast carcinoma were immunostained with a monoclonal antibody to retinoblastoma protein (PharMingen). Results were compared with known prognostic parameters of the primary tumor, estrogen and progesterone receptor status, proliferation index, and p16 (DAKO) expression. Lymph nodes from 38 of the 48 (79%) cases were pRb positive. There was no correlation of pRb staining alone with the primary tumor parameters studied or the proliferative index of the metastatic tumor. In 16 patients with both a sentinel node biopsy and an axillary lymph node dissection, 8 (50%) had metastatic breast carcinoma. The sentinel nodes of three of these eight patients (38%) were pRb negative (positive predictive value of 60% vs. 73% for p16). The remaining eight patients (50%) had no metastases in non-sentinel nodes, even though their sentinel nodes had metastatic breast carcinoma; six of these eight patients (75%) were pRb positive (negative predictive value of 55% vs. 83% for p16). pRb and p16 staining results combined showed that pRb-negative/p16-positive cases were associated with non-sentinel node metastases (positive predictive value of 100%) as well as poor prognostic parameters. Patients with the opposite staining profile (pRb positive and p16 negative) were mostly without non-sentinel node metastases (negative predictive value of 75%). Cases negative for both pRb and p16 were consistently associated with a better prognostic phenotype and absence of additional axillary node metastases. In conclusion, the presence or absence of pRb in sentinel nodes is of little predictive value for non-sentinel node metastases unless taken in conjunction with the presence of p16 staining. Instead, it appears to enhance the positive predictive value of p16 in determining the presence of non-sentinel node metastases. Due to the limited subgroup sample size in this study, clinical guidelines cannot be suggested as yet, but further research focused on the pRb-negative/p16-positivie and pRb-negative/p16-negative phenotypes may yield beneficial results.

Micrometastases in Sentinel Lymph Node in a Multicentric Study: Predictive Factors of Nonsentinel Lymph Node Involvement—Groupe Des Chirurgiens De La Federation Des Centres De Lutte Contre Le Cancer

Purpose

To determine the rate of nonsentinel lymph node (NSN) involvement at axillary lymph node dissection (ALND) and predictive factors of this involvement following detection of micrometastasis in sentinel nodes (SN).

Methods

We analyzed 700 observations of SN micrometastases with additional ALND with the characteristics of the patients, tumors, and SN.

Results

Involvement of SN was diagnosed 388 times by serial sections (55.4%) with standard hemoxylin and eosin staining (HES) and 312 times solely on immunohistochemical analysis (IHC; 44.6%). The accurate size of the micrometastases was indicated in 488 cases: 301 larger than 0.2 mm (61.7%) and 187 ≤ 0.2 mm (38.3%). Ninety-four patients (13.4%) presented an NSN involvement with only one NSN involved in 62 cases (66%). Predictive factors of NSN involvement were in univariate analysis (pT stage [P < .000], menopausal status [P = .048], T stage [P = .006], grade [P = .013], lymphovascular invasion [LVI; P = .013], histologic tumor type [P = .017], and method of micrometastasis detection, by HES or IHC [P = .015]) and in multivariate analysis (pT stage ≤ or > 20 mm [odds ratio, 2.54], micrometastases detected by HES or IHC [odds ratio,1.734], presence or absence of LVI [odds ratio, 1.706]). Micrometastasis size ≤ or greater than 0.2 mm was not predictive.

Conclusion

This study confirms the value of serial sections and the vital role played by IHC in screening for small micrometastases. Omission of additional ALND may be envisaged with minimal risk for pT1a and pT1b tumors, and pT1a-b-c tumors corresponding to tubular, colloidal, or medullar cancers.

Factors predicting the sentinel and non-sentinel lymph node metastases in breast cancer

The sentinel lymph node (SLN) is the only focus of axillary metastasis in a significant proportion of patients. In this single institutional study, clinicopathologic characteristics were investigated to determine the factors predicting the status of a SLN biopsy and the metastatic involvement of non-SLNs. Data were retrospectively reveiwed for 400 consecutive patients with clinical T1/T2 N0 breast cancer who underwent a SLN biopsy including axillary and/or internal mammary lymph nodes. The SLNs were evaluated by using the new AJCC staging criteria following multiple sectioning and immunohistochemical (IHC) analyses of nodes. The SLN contained metastases in 148 patients (38.5%) including 18 patients (12.2%) with micrometastases (<or=0.2 mm) and 130 patients (87.8%) with macrometastases (>0.2 cm). Five patients had isolated tumor cells detected by IHC (<or=0.2 mm, N(0i)). Patients with tumor size more than 2 cm (T1, 29.8% versus T2, 51.6%; OR=2.31, 95% CI, 1.50-3.56) and lymphovascular invasion (LVI-, 30.3% versus LVI+, 51.3%; OR=2.07, 95% CI, 1.34-3.19) were more likely to have positive SLNs in both univariate and multivariate analyses. Among patients with a positive SLN biopsy, those with T2 tumors (versus T1; 63.1% versus 36.9; OR=2.93, 95% CI, 1.43-6.04), macrometastases in SLNs (versus micrometastases; 88.9% versus 11.1%; OR=8.83; 95% CI, 1.82-42.87) and extracapsular node extension (versus without extracapsular node extension; 65.4% versus 34.6%; OR, 2.23; 95% CI, 1.05-4.72) were more likely to have non-SLN metastases in both univariate and multivarite analyses. These results indicate that clinicopathologic factors might be helpful to select patients who were less likely to have negative SLN or non-SLNs. However, additional factors are still needed to be identified to omit surgical axillary staging.

Primary tumor characteristics predict sentinel lymph node macrometastasis in breast cancer

Selective sentinel lymphadenectomy (SSL) is rapidly becoming the standard of care in the surgical management of patients with early breast cancer. Sentinel lymph node macrometastasis has been well documented in the literature to have a higher risk of nonsentinel node tumor involvement when compared to micrometastasis. The aim of our study was to determine the primary tumor characteristics associated with sentinel node macrometastasis that will allow us to preoperatively determine this subgroup of patients at risk. This study was a retrospective review of 644 patients who underwent successful SSL as part of their surgical treatment of breast cancer at the University of California San Francisco Carol Franc Buck Breast Care Center from November 1997 to August 2003. All patients underwent preoperative lymphoscintigraphy followed by wide excision or mastectomy and sentinel lymphadenectomy with or without axillary lymph node dissection. One hundred twenty-two patients had positive sentinel nodes on histology. Micrometastasis was present in 43 of these patients and macrometastasis in the remaining 79. Statistical analysis showed that a tumor size greater than 15 mm, poor tubule formation by the tumor cells, and lymphovascular invasion were significantly associated with sentinel node macrometastasis. A high mitotic count showed a trend but was not significant in our study. Patients with a tumor size greater than 15 mm, poor tubule formation, and lymphovascular invasion are at risk of having sentinel node macrometastasis. These patients can be identified preoperatively based on imaging and biopsy criteria, allowing the option of selective intraoperative pathologic evaluation of the sentinel node and immediate completion axillary dissection as necessary.

Evaluation of a breast cancer nomogram for prediction of non-sentinel lymph node positivity

AIMS

This study evaluates the breast cancer nomogram (BCN), an online tool developed by Memorial Sloan-Kettering Cancer Center to determine the rate of non-SLN positivity, in an independent cohort of SLN positive patients.

MATERIAL AND METHODS

Available data between 02/2000 and 06/2004 in two prospective databases, 749 cases had successful SLN biopsy including 149 axillary-SLN metastases study cases. These cases had accurately graded tumours up to 9 cm in size and CAD with a minimum total 10 nodes removed. Histopathological assessment of nodes included hematoxylin and eosin staining and/or immunohistochemistry. Computerized BCN was used to estimate probability of non-SLN positivity and compared with actual probability after grouping into deciles.

RESULTS

The trend of actual probability in various decile groups was comparable to the predicted probability. An area under the receiver operating characteristic curve was 0.75 as compared to 0.76 in the original study.

CONCLUSION

Although this study is small, the results are encouraging and suggest the nomogram is a useful tool to estimate the likelihood of positive axillary non-SLN. However, variations in pathological assessment between centres are the major impediment to widespread application of BCN. If SLN positive patients decline the standard recommendation of CAD or entry into clinical trials evaluating the significance of CAD then the BCN could help in decision making.

EXPERIENCE OF SENTINEL NODE BIOPSY ALONE IN EARLY BREAST CANCER WITHOUT FURTHER AXILLARY DISSECTION IN PATIENTS WITH NEGATIVE SENTINEL NODE

AIMS

The aims of surgical therapy of breast cancer are loco-regional tumour control and staging. Axillary staging is still considered the single most important prognostic indicator in breast cancer. Surgical removal of axillary nodes remains the standard way to assess their involvement in most centres. The morbidity associated with axillary dissection (AD) is well recognized. In recent years sentinel node biopsy (SNB) has evolved. Multiple studies suggest it has the same accuracy as AD in axillary staging and less morbidity in early breast cancer (EBC). SNB has become the standard of practice in EBC in many parts of the world. In Australia, the preference has been to wait for the results of the Sentinel Node versus Axillary Clearance (SNAC) trial as well as other international trials before accepting SNB as a standard of care. The experience of a single surgeon with SNB alone in EBC without further completion axillary dissection (CAD) in negative sentinel node (SLN) is described in the present paper.

METHODS

An audit was done of the senior author's prospective data from the Royal Australasian College of Surgeons database. Other information was added retrospectively from case notes.

RESULTS

Between December 2000 and December 2003, 154 EBC cases (153 patients) underwent SNB alone. An average of four SLN was removed. Of these cases, 31.8% had positive SLNs (excluding 2.6% cases that had isolated tumour cells), of these, 93.9% had metastases (39.1% micro- and 60.9% macro-metastases) in axillary-SLN (ASLN) and almost all of these had CAD. ASLNs were the only positive nodes in 73.9%. Extra-ASLN retrieved in 68.8% of 34% demonstrated on lymphoscintigraphy. Of these, 12.1% were positive (6.1% micro- and macro-metastases each), all internal mammary. Mean follow up was 22.1 months. There was one local-regional-systemic and one systemic recurrence over this time.

CONCLUSION

SNB has a valid role in staging of the axilla particularly in low-risk patients. After adequate self audit, SNB offers a minimal morbidity and reliable method of axillary staging. Patients choosing SNB alone must understand that the long-term results of the randomized controlled trial are still pending for level I evidence of long-term efficacy.

Prediction of non-sentinel lymph node status in breast cancer with a micrometastatic sentinel node

Background

Axillary lymph node dissection (ALND) may not be necessary in women with breast cancer who have micrometastasis in a sentinel node (SN), owing to the low risk of non-SN (NSN) involvement. The aim of this study was to identify a subgroup of women with a micrometastatic SN and a negligible risk of positive NSNs in whom ALND may be avoided.

Methods

Some 237 of 241 women with a macrometastatic SN and 122 of 138 with a micrometastatic SN underwent completion ALND and were compared with respect to NSN involvement. The 122 patients with SN micrometastasis were further analysed to determine factors that could predict the risk of positive NSNs.

Results

A total of 121 (51·1 per cent) of 237 women with SN macrometastasis had positive NSNs compared with 22 (18·0 per cent) of 122 with SN micrometastasis (P &lt; 0·001). Multivariate analysis showed that size of SN micrometastasis (odds ratio 3·49 (95 per cent confidence interval (c.i.) 1·32 to 9·23); P = 0·012) and presence of lymphovascular invasion (odds ratio 0·23 (95 per cent c.i. 0·05 to 1·00); P = 0·050) were significantly associated with positive NSNs. SN micrometastasis less than 0·5 mm in diameter combined with absence of lymphovascular invasion was associated with an 8·5 per cent risk of NSN involvement.

Conclusion

Size of micrometastasis and presence of lymphovascular invasion were significantly related to the risk of finding additional positive axillary lymph nodes when the SN contained only micrometastasis.

Breast cancer patients with pN0(i+) and pN1(mi) sentinel nodes have high rate of nonsentinel node metastases

BACKGROUND

The recent American Joint Committee on Cancer revision of the staging system for breast cancer classifies sentinel node metastases < 0.2 mm (pN0[i+]) as node negative and those > 0.2 mm but < 2 mm are designated pN1(mi). We examined the association between size of sentinel node metastases and rate of nonsentinel node metastases, specifically in the subgroup of patients with micrometastases.

STUDY DESIGN

We examined the nonsentinel nodes of 124 patients with positive sentinel nodes and correlated the likelihood of nonsentinel node involvement with the size of the metastasis in the sentinel node and primary tumor characteristics.

RESULTS

Nonsentinel node metastases were found in 19% (6 of 31) of patients with sentinel node metastases <or= 0.2 mm, 20% (6 of 30) of patients with metastases 0.2 mm to 2 mm, and 46% (29 of 63) of patients with metastases > 2 mm. Multivariate analysis found that involvement of the majority of sentinel nodes (p = 0.01) and sentinel metastases > 2 mm (p = 0.001) were significantly related to presence of metastases in nonsentinel nodes. Age, tumor size, pathology, multifocality, satellites, and lymphovascular invasion were not significantly related to nonsentinel node metastases in multivariate analysis.

CONCLUSIONS

These findings indicate that frequency of nonsentinel node metastases with sentinel node metastases <or= 0.2 mm is comparable to the frequency when sentinel metastases are > 0.2 to 2 mm. Omitting complete axillary dissection in pN1(mi) and pN0(i+) patients may leave residual disease in up to 20% of these patients.

Predicting the risk for additional axillary metastases in patients with breast carcinoma and positive sentinel lymph node biopsy

OBJECTIVE

To assess whether the risk for nonsentinel node metastases may be predicted, thus sparing a subgroup of patients with breast carcinoma and a positive sentinel lymph node (SLN) biopsy completion axillary lymph node dissection (ALND).

SUMMARY BACKGROUND DATA

The SLN is the only involved axillary lymph node in the majority of the patients undergoing ALND for a positive SLN biopsy. A model to predict the status of nonsentinel axillary lymph nodes could help tailor surgical therapy to those patients most likely to benefit from completion ALND.

METHODS

All the axillary sentinel and nonsentinel lymph nodes of 1228 patients were reviewed histologically and reclassified according to the current TNM classification of malignant tumors as bearing isolated tumor cells only, micrometastases, or (macro)metastases. The prevalence of metastases in nonsentinel lymph nodes was correlated to the type of SLN involvement and the size of the metastasis, the number of affected SLNs, and the prospectively collected clinicopathologic variables of the primary tumors.

RESULTS

In multivariate analysis, further axillary involvement was significantly associated with the type and size of SLN metastases, the number of affected SLNs, and the occurrence of peritumoral vascular invasion in the primary tumor. A predictive model based on the characteristics most strongly associated with nonsentinel node metastases was able to identify subgroups of patients at significantly different risk for further axillary involvement.

CONCLUSIONS

Patients with the most favorable combination of predictive factors still have no less than 13% risk for nonsentinel lymph node metastases and should be offered completion ALND outside of clinical trials of SLN biopsy without back-up axillary clearing.

The prevalence of non-sentinel node metastases in breast cancer patients with sentinel node micrometastases

AIMS

The aim of the study was to estimate the prevalence of and risk factors for non-sentinel node (NSN) involvement in breast cancer patients with sentinel node (SN) micrometastases.

METHODS

Eighty-four patients with SN micrometastases were included. Both the SN and NSN were examined using serial sectioning and immunohistohemistry. Various indices were evaluated as possible risk factors for NSN involvement.

RESULTS

NSN involvement was found in 22/84 patients. The median size of the NSN metastases was 1.25 mm (0.01-12 mm). The NSN metastases were larger than 2 mm in 8 patients and smaller than 0.2 mm in 6 patients. NSN involvement was observed in 14/35 patients with metastatic findings in all removed SN. Three of the 23 patients with 2 or 3 tumour negative SN had NSN metastases. None of the 12 patients with 4 or more uninvolved SN had NSN metastases. NSN involvement could not excluded by other patient, tumour or sentinel node related factors.

CONCLUSIONS

Every fourth patient will have residual disease in the axilla, 10% even large metastases, if axillary clearance is omitted in patients with SN micrometastases. The risk of NSN involvement seems negligible in patients with a single SN micrometastasis and four or more healthy SN harvested.

Surgical implications of sentinel node with micrometastatic disease in invasive breast cancer

AIM

To assess the rate of positive axillary clearance (AC) when the sentinel node biopsy (SNB) contains micrometastatic disease in invasive breast cancer and to evaluate the factors that could predict positivity.

PATIENTS AND METHODS

This is a prospective study carried out on 542 successive women undergoing SNB for unifocal T0-T1 N0 invasive breast cancer without previous treatment.

RESULTS

Five hundred and twenty-five sentinel nodes (SN) were found, 142 contained metastases. Fifty-five of the positive SN contained micrometastatic disease only. Of them, 40 patients underwent completion of AC. Six out of 40 patients who had micrometastatic SN had a positive AC, five for micrometastasis between 0.2 and 2 mm (5/34), one for isolated cells in the SN (1/6). None of the studied factors (age, histological tumour size, histological grade, estradiol receptor (ER), histological tumour type, size and method of micrometastasis detection) could significantly predict the status of the AC.

CONCLUSION

As long as the results of ongoing prospective randomised studies are unknown, it remains necessary to perform AC when the SNB contains micrometastatic disease, whatever the size or the detection mode of the metastasis.

Intraoperative Examination of Sentinel Nodes in Breast Cancer: Is the Glass Half Full or Half Empty?

BACKGROUND

Intraoperative identification of positive sentinel lymph nodes in patients with breast cancer may avoid a return to the operating room.

METHODS

In a group of 402 consecutive patients with primary breast cancer who underwent sentinel lymph node biopsy, an intraoperative examination (IE) was obtained in 236 cases either by frozen section (FS; n = 68) or by touch preparation cytology (TP; n = 168).

RESULTS

IE had an accuracy of 89% (209 of 236), but it identified only 52 of 77 positive cases (sensitivity, 68%). There were 25 false-negative cases (13.7%), of which 7 were macrometastases and 18 by micrometastases (P < .001). Six macrometastases were missed by TP and one by FS (P = .9). There were two false-positive cases (3.7%). Overall, 48 (20%) of 236 patients avoided a delayed return to the operating room for a completion lymphadenectomy because of IE findings. This occurred in 10% of patients with tumors <1 cm in diameter, in 20% of those with tumors between 1 and 2 cm, and in 34% of those with tumors >2 cm in diameter (P = .05). The cost savings for the Italian Health System amounted to 198,040 (US$223,794) in these patients.

CONCLUSIONS

IE has acceptable sensitivity for lymph node macrometastases, but it is a weak tool for diagnosing micrometastases. FS and TP are roughly equivalent. IE allows management changes, because approximately 20% of all patients are expected to undergo synchronous axillary dissection, and it is particularly helpful in T2 patients. This may allow substantial cost savings for the health-care system.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Sentinel node biopsy in breast cancer and melanoma requires adequate self‐audit

BACKGROUND

Sentinel node biopsy (SNB) is an evolving technique with potential for improving staging. Melanoma and breast cancer are the two most commonly used applications. The present study relates the author's validation data in both diseases.

METHODS

Review of a prospective database.

RESULTS

Between January 2000 and December 2001 92 cases of breast cancer were offered SNB. The first 48 had completion axillary dissection. The identification rate was 92%. There were 28 true negative, 15 true positive and one false negative case. A mean of 2.0 nodes were removed (range 1-4). Completion axillary dissection removed a mean of 15.1 nodes. The following 44 cases were offered a choice of SNB alone, axillary dissection or a combination of techniques. Thirty-seven women chose SNB alone. There was one technical failure, 28 negative SNB and eight positive SNB results. A mean of 3.1 lymph nodes were removed (range 1-9) applying a 10% rule. At 24-36 months follow up there have been no cases of locoregional recurrence. From January to December 2001 36 cases of melanoma > or =1 mm were managed with SNB. Twenty-eight SNB were negative and eight were positive (22%). At follow up (range 12-24 months) there were three locoregional recurrences, but only one of these were in the node basin determined to be previously negative by SNB (3.5%).

DISCUSSION

Sentinel node biopsy in breast cancer is a valid alternative to full axillary dissection for staging the axilla. Patients can make an informed choice to have SNB alone if they understand the limitations of the technique and possible consequences of these limitations. In melanoma SNB provides valuable prognostic information most melanoma patients prefer to have. Adequate self-audit is necessary before a patient can make an informed decision to have SNB in either disease.

[Sentinel lymph node biopsy in breast cancer: state of the art]

Axillary lymph node excision of level I and II with at least 10 lymph nodes is the operative gold standard for invasive breast cancer. Axillary lymph node excision is a diagnostic procedure for histopathologic tumor classification, for assessment of prognosis, local tumor control and adjuvant therapy decision. The sentinel node biopsy is a minimal-invasive procedure to determine the axillary lymph node status by excision of one or more sentinel nodes. This procedure is being increasingly implemented in breast cancer surgery. The classical axillary lymph node excision can be replaced by sentinel node biopsy if sentinel nodes are free of invasion in the intraoperative as well as in the final histopathological report. Sentinel node biopsy can become an operative routine procedure only in a quality-controlled environment.

A nomogram for predicting the likelihood of additional nodal metastases in breast cancer patients with a positive sentinel node biopsy

BACKGROUND

The standard of care for breast cancer patients with sentinel lymph node (SLN) metastases includes complete axillary lymph node dissection (ALND). However, many question the need for complete ALND in every patient with detectable SLN metastases, particularly those perceived to have a low risk of non-SLN metastases. Accurate estimates of the likelihood of additional disease in the axilla could assist greatly in decision-making regarding further treatment.

METHODS

Pathological features of the primary tumor and SLN metastases of 702 patients who underwent complete ALND were assessed with multivariable logistic regression to predict the presence of additional disease in the non-SLNs of these patients. A nomogram was created using pathological size, tumor type and nuclear grade, lymphovascular invasion, multifocality, and estrogen-receptor status of the primary tumor; method of detection of SLN metastases; number of positive SLNs; and number of negative SLNs. The model was subsequently applied prospectively to 373 patients.

RESULTS

The nomogram for the retrospective population was accurate and discriminating, with an area under the receiver operating characteristic (ROC) curve of 0.76. When applied to the prospective group, the model accurately predicted likelihood of non-SLN disease (ROC, 0.77).

CONCLUSIONS

We have developed a user-friendly nomogram that uses information commonly available to the surgeon to easily and accurately calculate the likelihood of having additional, non-SLN metastases for an individual patient.

Clinicopathologic features of metastasis in nonsentinel lymph nodes of breast carcinoma patients

BACKGROUND

In breast carcinoma patients with a positive sentinel lymph node (SN), the value of complete axillary lymph node dissection has been questioned. Multiple published reports have attempted to identify clinicopathologic characteristics of the primary tumor and SN that are associated with an increased likelihood of positive nonsentinel lymph nodes (NSN). Because of differences in lymph node evaluation techniques and limited patient numbers in each study, the authors performed a meta-analysis to assess the regularity and relative strength of association between various characteristics and the risk of NSN metastasis.

METHODS

A MEDLINE search identified 15 candidate studies, 11 of which met the criteria for analysis. General elements of the studies, the pathologic characteristics evaluated, and the results for selected characteristics were compared. Original data were abstracted from each study and used to calculate odds ratios. The Mantel-Haenszel common odds ratios were calculated to determine the relative strength of the associations.

RESULTS

Despite methodologic differences, the correlation between positive NSNs and certain pathologic characteristics was found to be remarkably similar among studies. The 5 individual characteristics found to be associated with the highest likelihood of NSN metastasis are SN metastasis > 2 mm in size, extranodal extension in the SN, tumor size > 2 cm, > 1 positive SN, and lymphovascular invasion in the primary tumor.

CONCLUSIONS

There is general concordance among studies regarding the association between pathologic characteristics and NSN metastasis in breast carcinoma patients with a positive SN. The pooled analysis identified those factors with the strongest associations that should be evaluated routinely in SN specimens and included in prospective databases for the development of a predictive model.

Predictive Factors for the Status of Non-sentinel Nodes in Breast Cancer Patients with Tumor Positive Sentinel Nodes

In patients with tumor positive sentinel nodes, axillary lymph node dissection is routinely performed while a majority of these patients have no tumor involvement in the non-sentinel nodes. The authors tried to identify a subgroup of patients with a tumor positive sentinel node without non-sentinel node tumor involvement. In 135 consecutive patients with tumor positive sentinel nodes and axillary lymph node dissection performed, the incidence of non-sentinel node involvement according to tumor and sentinel node related factors was examined. The size of the sentinel node metastasis, size of primary tumor and number of tumor positive sentinel nodes were the three factors significantly predicting the status of the non-sentinel nodes. The size of the sentinel node metastasis was the strongest predictive factor (P < 0.0001). In a subgroup of 41 patients with a stage T1 tumor and micrometastatic involvement in the sentinel node only 2 patients (5%) had non-sentinel node involvement. In patients with small primary tumors and micrometastatic involvement of the sentinel nodes, the chance of non-sentinel node involvement is small but cannot be discarded. Because the clinical relevance of micrometastases in lymph nodes is still unclear it is not advisable to omit axillary lymph node dissection even in these patients.

The feasibility of intraoperative diagnosis of sentinel lymph node metastases in breast cancer

BACKGROUND AND OBJECTIVES

The aim of the study was to analyse in detail the feasibility of intraoperative assessment of sentinel lymph nodes in breast cancer.

METHODS

Altogether 139 consecutive breast cancer patients with metastases in axillary sentinel nodes were included in a prospective study. A combination of imprint cytology and frozen section was used as the method of intraoperative diagnosis of sentinel node metastases. The definite postoperative evaluation of the sentinel nodes was taken as the gold standard.

RESULTS

The overall sensitivity of intraoperative diagnosis was 83%, reaching 81% if the intraoperative assessment had been limited to the two first retrieved sentinel nodes. False negative (FN) findings were more common in connection with invasive lobular carcinoma (28%) than with invasive ductal carcinoma (8%) (P < 0.01) as well as in connection with micro-metastases, in 38% of the cases, compared to the larger metastases, 6% (P < 0.00005).

CONCLUSIONS

Intraoperative examination of sentinel lymph nodes enables breast surgery, axillary staging, and treatment in the same operation in a substantial proportion of breast cancer patients. Hospital costs as well as workload in the pathology laboratory may be reduced, limiting the intraoperative assessment to the two first retrieved nodes.

Pathological work-up of sentinel lymph nodes in breast cancer. Review of current data to be considered for the formulation of guidelines

Controversies and inconsistencies regarding the pathological work-up of sentinel lymph nodes (SNs) led the European Working Group for Breast Screening Pathology (EWGBSP) to review published data and current evidence that can promote the formulation of European guidelines for the pathological work-up of SNs. After an evaluation of the accuracy of SN biopsy as a staging procedure, the yields of different sectioning methods and the immunohistochemical detection of metastatic cells are reviewed. Currently published data do not allow the significance of micrometastases or isolated tumour cells to be established, but it is suggested that approximately 18% of the cases may be associated with further nodal (non-SN) metastases, i.e. approximately 2% of all patients initially staged by SN biopsy. The methods for the intraoperative and molecular assessment of SNs are also surveyed.