Clinicopathologic Features Associated With Having Four or More Metastatic Axillary Nodes in Breast Cancer Patients With a Positive Sentinel Lymph Node

Prediction of High Nodal Burden in Patients With Sentinel Node-Positive Luminal ERBB2-Negative Breast Cancer

Importance

In patients with clinically node-negative (cN0) breast cancer and 1 or 2 sentinel lymph node (SLN) macrometastases, omitting completion axillary lymph node dissection (CALND) is standard. High nodal burden (≥4 axillary nodal metastases) is an indication for intensified treatment in luminal breast cancer; hence, abstaining from CALND may result in undertreatment.

Objective

To develop a prediction model for high nodal burden in luminal ERBB2-negative breast cancer (all histologic types and lobular breast cancer separately) without CALND.

Design, Setting, and Participants

The prospective Sentinel Node Biopsy in Breast Cancer: Omission of Axillary Clearance After Macrometastases (SENOMAC) trial randomized patients 1:1 to CALND or its omission from January 2015 to December 2021 among adult patients with cN0 T1-T3 breast cancer and 1 or 2 SLN macrometastases across 5 European countries. The cohort was randomly split into training (80%) and test (20%) sets, with equal proportions of high nodal burden. Prediction models were developed by multivariable logistic regression in the complete luminal ERBB2-negative cohort and a lobular breast cancer subgroup. Nomograms were constructed. The present diagnostic/prognostic study presents the results of a prespecified secondary analysis of the SENOMAC trial. Herein, only patients with luminal ERBB2-negative tumors assigned to CALND were selected. Data analysis for this article took place from June 2023 to April 2024.

Exposure

Predictors of high nodal burden.

Main Outcomes and Measures

High nodal burden was defined as ≥4 axillary nodal metastases. The luminal prediction model was evaluated regarding discrimination and calibration.

Results

Of 1010 patients (median [range] age, 61 [34-90] years; 1006 [99.6%] female and 4 [0.4%] male), 138 (13.7%) had a high nodal burden and 212 (21.0%) had lobular breast cancer. The model in the training set (n = 804) included number of SLN macrometastases, presence of SLN micrometastases, SLN ratio, presence of SLN extracapsular extension, and tumor size (not included in lobular subgroup). Upon validation in the test set (n = 201), the area under the receiver operating characteristic curve (AUC) was 0.74 (95% CI, 0.62-0.85) and the calibration was satisfactory. At a sensitivity threshold of ≥80%, all but 5 low-risk patients were correctly classified corresponding to a negative predictive value of 94%. The prediction model for the lobular subgroup reached an AUC of 0.74 (95% CI, 0.66-0.83).

Conclusions and Relevance

The predictive models and nomograms may facilitate systemic treatment decisions without exposing patients to the risk of arm morbidity due to CALND. External validation is needed.

Trial Registration

ClinicalTrials.gov Identifier: NCT02240472.

Axillary Staging Is Not Justified in Postmenopausal Clinically Node-Negative Women Based on Nodal Disease Burden

BACKGROUND

RxPONDER showed no benefit of adjuvant chemotherapy in postmenopausal women with estrogen receptor (ER) positive/human epidermal growth factor receptor 2 (HER2) negative breast cancer and limited nodal burden (pN1) with a recurrence score ≤ 25, suggesting that axillary staging could be omitted in cN0 patients if significant numbers of such women do not have pN2-3 disease. Here we evaluate the pN2-3 disease rate in a large cohort of postmenopausal women presenting with cN0 breast cancer.

PATIENTS AND METHODS

Consecutive postmenopausal patients presenting with T1-2N0 breast cancer who underwent axillary surgery from February 2006 to December 2011 were identified. Clinicopathologic characteristics associated with pN2-3 disease were examined using chi-square or Fisher's exact tests.

RESULTS

Of 3363 postmenopausal women with cT1-2N0 breast cancer (median age 58 years, IQR 48-67 years), median tumor size was 1.3 cm (IQR 0.90-1.90cm). Post-axillary staging, 2600 (77.3%) were pN0, 643 (19.1%) were pN1, and 120 (3.6%) were pN2-3. The pN2-3 disease rate did not differ across subtypes (4.4% HER2+, 3.5% HR-/HER2-, 3.5% HR+/HER2-, p = 0.70). In the subset with HR+/HER2- tumors, on multivariable analysis, age < 65 years (odds ratio [OR] 2.38, 95% confidence interval [CI] 1.32-4.49), lymphovascular invasion (OR 5.29, 95% CI 2.72-11.2), multifocal/centric tumors (OR 3.08, 95% CI 1.79-5.32), and tumor size > 2 cm (OR 5.51, 95% CI 3.05-10.4) were significantly associated with pN2-3 nodal burden. Of 506 patients with tumors > 2 cm, 49 (9.7%) had pN2-3 disease; in the subset of 90 patients age < 65 years who had multifocal/centric tumors > 2 cm, 23 (25.6%) had pN2-3 disease.

CONCLUSIONS

In postmenopausal women with cN0 disease, pN2-3 nodal burden is uncommon; omitting axillary staging would not miss a significant number of patients who might benefit from adjuvant chemotherapy. Information available preoperatively indicating a higher risk of nodal disease such as younger age and large, multifocal tumors should be considered in the multidisciplinary management of the axilla.

Prevalence of extracapsular extension in metastatic sentinel lymph nodes in breast cancer

INTRODUCTION

Axillary lymph node involvement is recognized as a key prognostic factor for invasive breast cancer. Retrospective analyzes have shown that extracapsular extension (ECE) is correlated with negative prognostic factors in this neoplasia.

OBJECTIVE

to evaluate the measurement of ECE and its relationship with the number of affected non-sentinel lymph nodes, as well as to investigate the association between ECE with other clinical and pathological prognostic factors.

METHODS

This is a cross-sectional observational study carried out from January 2015 to June 2019, at the Breast Surgical Oncology service of Liga Contra o Cancer (LIGA), in Natal, Brazil. A total of 150 patients were included in the study and were divided into three groups: absence of ECE, ECE less than or equal to 2 mm and ECE greater than 2 mm.

RESULTS

The mean age was 58 years for the group with ECE and 57 years for the group without ECE. Most of the patients were mixed race (66.7%), had no family history of breast cancer (64%) and underwent quadrantectomy (64.5%). Regarding the characteristics of the disease, most presented a histological report compatible with Invasive Carcinoma of the non-special type (IC NST) (87.5%), histological grade II (52.7%), negative Lymphovascular invasion (LVI) (52.7%), Tumor Size T1 (<2.0 cm) (52%) and Luminal B molecular subtype (36.7%). Regarding sentinel lymph nodes: 103 patients (68.7%) had ECE and 1 positive sentinel lymph node was identified in most cases. There was a statistically significant association between the presence of ECE and of being mixed race (p = 0.03), between ECE and LVI (p = 0.05) and between ECE and a greater number of positive non-sentinel lymph nodes (p < 0.001).

CONCLUSION

Our study showed that ECE> 2 mm is associated with increased axillary nodal load compared to groups without ECE and ECE ≤ 2 mm in sentinel node biopsy in patients who met the Z0011 criteria.

Clinical significance of extranodal extension in sentinel lymph node positive breast cancer

The precise stage of lymph node (LN) metastasis is a strong prognostic factor in breast cancers, and sentinel lymph node (SLN) is the first station of nodal metastasis. A number of patients have extranodal extension (ENE) in SLN, whereas the clinical values of ENE in SLN in breast cancers are still in exploration. The aim of our study was to evaluate the predictive and prognostic values of ENE in SLN in breast cancers, and to investigate the feasibility of ENE to predict non-SLN metastasis, nodal burden, disease free survival (DFS) and overall survival (OS) in clinical practice. 266 cases of primary invasive breast cancer (cT1-2N0 breast cancer) underwent SLN biopsy and axillary lymph node dissection (ALND) between 2008 and 2015 were extracted from the pathology database of Fudan University Shanghai Cancer Center. ENE in SLN was defined as extension of neoplastic cells through the lymph-nodal capsule into the peri-nodal adipose tissue, and was classified as no larger than 2 mm and larger than 2 mm group. The associations between ENE and clinicopathological features, non-SLN metastasis, nodal burden, DFS, and OS were analyzed. In the 266 patients with involved SLN, 100(37.6%) were positive for ENE in SLN. 67 (25.2%) cases had ENE no larger than 2 mm in diameter, and 33(12.4%) had ENE larger than 2 mm. Among the clinicopathological characteristics, the presence of ENE in SLN was associated with higher pT and pN stages, PR status, lympho-vascular invasion. Logistic regression analysis indicated that patients with ENE in SLN had higher rate of non-SLN metastasis (OR4.80, 95% CI 2.47–9.34, P < 0.001). Meanwhile, in patients with SLN micrometastasis or 1–2 SLNs involvement, ENE positive patients had higher rate of non-SLN metastasis, comparing with ENE negative patients (P < 0.001, P = 0.004 respectively). The presence of ENE in SLN was correlated with nodal burden, including the pattern and number of involved SLN (P < 0.001, P < 0.001 respectively), the number of involved non-SLN and total positive LNs (P < 0.001, P < 0.001 respectively). Patients with ENE had significantly higher frequency of pN2 disease (P < 0.001). For the disease recurrence and survival status, Cox regression analysis showed that patients with ENE in SLN had significantly reduced DFS (HR 3.05, 95%CI 1.13–10.48, P = 0.008) and OS (HR 3.34, 95%CI 0.74–14.52, P = 0.092) in multivariate analysis. Kaplan–Meier curves and log-rank test showed that patients with ENE in SLN had lower DFS and OS (for DFS: P < 0.001; and for OS: P < 0.001 respectively). Whereas no significant difference was found in nodal burden between ENE ≤ 2 mm and > 2 mm groups, except the number of SLN metastasis was higher in patients with ENE > 2 mm. Cox regression analysis, Kaplan–Meier curves and log-rank test indicated that the size of ENE was not an independent factor of DFS and OS. Our study indicated that ENE in SLN was a predictor for non-SLN metastasis, nodal burden and prognosis in breast cancers. Patients with ENE in SLN had a higher rate of non-SLN metastasis, higher frequency of pN2 disease, and poorer prognosis. Patients with ENE in SLN may benefit from additional ALND, even in SLN micrometastasis or 1–2 SLNs involvement patients. The presence of ENE in SLN should be evaluated in clinical practice. Size of ENE which was classified by a 2 mm cutoff value had no significant predictive and prognostic values in this study. The cutoff values of ENE in SLN need further investigation.

Intraoperative prediction of the two axillary lymph node macrometastases threshold in patients with breast cancer using a one-step nucleic acid cytokeratin-19 amplification assay

The aim of the present study was to assess the sensitivity, specificity and practicality of using a one-step nucleic acid amplification (OSNA) assay during breast cancer staging surgery to predict and discriminate between at least 2 involved nodes and more than 2 involved nodes and facilitate the decision to provide axillary conservation in the presence of a low total axillary node tumour burden. A total of 700 consecutive patients, not treated with neo-adjuvant chemotherapy, received intraoperative sentinel lymph node (SLN) analysis using OSNA for cT1-T3 cN0 invasive breast cancer. Patients with at least one macrometastasis on whole-node SLN analysis underwent axillary lymph node dissection (ALND). The total tumour load (TTL) of the macrometastatic SLN sample was compared with the non-sentinel lymph node (NSLN) status of the ALND specimen using routine histological assessment. In total, 122/683 patients (17.9%) were found to have an OSNA TTL indicative of macrometastasis. In addition, 45/122 (37%) patients had NSLN metastases on ALND with a total positive lymph node burden exceeding the American College of Surgeons Oncology Group Z0011 trial threshold of two macrometastatic nodes. The TTL negative predictive value was 0.975 [95% confidence interval (CI), 0.962-0.988]. The area under the curve for the receiver operating characteristic curve was 0.86 (95% CI, 0.81-0.91), indicating that SLN TTL was associated with the prediction (and partitioning) of total axillary disease burden. OSNA identifies a TTL threshold value where, in the presence of involved SLNs, ALND may be avoided. This technique offers objective confidence in adopting conservative management of the axilla in patients with SLN macrometastases.

Risk Factors for a False-Negative Result of Sentinel Node Biopsy in Patients with Clinically Node-Negative Breast Cancer

Purpose

Although sentinel lymph node biopsy (SLNB) can accurately represent the axillary lymph node (ALN) status, the false-negative rate (FNR) of SLNB is the main concern in the patients who receive SLNB alone instead of ALN dissection (ALND).

Materials and Methods

We analyzed 1,886 patientswho underwent ALND after negative results of SLNB,retrospectively. A logistic regression analysis was used to identify risk factors associated with a falsenegative (FN) result. Cox regression model was used to estimate the hazard ratio of factors affecting disease-free survival (DFS).

Results

Tumor located in the upper outer portion of the breast, lymphovascular invasion, suspicious node in imaging assessment and less than three sentinel lymph nodes (SLNs) were significant independent risk factors for FN in SLNB conferring an adjusted odds ratio of 2.10 (95% confidence interval [CI], 1.30 to 3.39), 2.69 (95% CI, 1.47 to 4.91), 2.59 (95% CI, 1.62 to 4.14), and 2.39 (95% CI, 1.45 to 3.95), respectively. The prognostic factors affecting DFS were tumor size larger than 2 cm (hazard ratio [HR], 1.86; 95% CI, 1.17 to 2.96) and FN of SLNB (HR, 2.51; 95% CI, 1.42 to 4.42) in SLN-negative group (FN and true-negative), but in ALN-positive group (FN and true-positive), FN of SLNB (HR, 0.64; 95% CI, 0.33 to 1.25) did not affect DFS.

Conclusion

In patients with risk factors for a FN such as suspicious node in imaging assessment, upper outer breast cancer, less than three harvested nodes, we need attention to find another metastatic focus in non-SLNs during the operation. It may contribute to provide an exact prognosis and optimizing adjuvant treatments.

Predictive factors for the occurrence of four or more axillary lymph node metastases in ER-positive and HER2-negative breast cancer patients with positive sentinel node: A retrospective cohort study

INTRODUCTION

Patients with four or more axillary lymph node metastases have benefited from postmastectomy radiotherapy to the supraclavicular region. However, when metastatic sentinel nodes (SNs) are present, information regarding the total number of node metastases cannot be obtained if axillary lymph node dissection (ALND) is omitted from the treatment protocol. It is important to determine the indication for additional chemotherapy in ER-positive and HER2-negative breast cancer patients. We investigated the predictive factors for the occurrence of four or more metastases in patients with ER-positive and HER2-negative breast cancer in the presence of macrometastasis in the SNs.

METHODS

We reviewed 83 patients with ER-positive and HER2-negative breast cancer, who had macrometastasis in the SN and had undergone ALND. The clinicopathological findings and prognosis between patients with pN1 disease and those with pN2 disease were also compared.

RESULTS

Nineteen percent of patients had pN2-3 disease. The predictive factor for poor prognosis in these patients was the presence of pN2-3 disease. The independent predictive factors for pN2-3 disease were the T stage and the ratio of the number positive SNs to the number of removed SNs (SN ratio). Patients with both T2 tumors and a high SN ratio had a 50% risk of having pN2-3 disease.

CONCLUSION

The presence of four or more metastases was found to be the strongest prognostic factor in ER-positive and HER2-negative breast cancer patients with macrometastasis in the SN. The T stage and SN ratio determined before surgery or during surgery were useful in predicting pN2-3 disease in these patients.

One-step nucleic acid amplification assay for intraoperative prediction of advanced axillary lymph node metastases in breast cancer patients with sentinel lymph node metastasis

The one-step nucleic acid amplification (OSNA) assay is used to semiquantitatively measure the cytokeratin (CK)19 mRNA copy numbers of each sentinel lymph node (SLN) in breast cancer patients. The aim of the present study was to evaluate whether the diagnosis of ≥4 LN metastases is possible using the OSNA assay intraoperatively. Between May, 2010 and December, 2014, a total of 134 patients who underwent axillary lymph node dissection (ALND) of positive SLNs were analyzed. The total tumor load (TTL) was defined as the total CK19 mRNA copies of all positive SLNs. The correlation between TTL and ≥4 LN metastases was evaluated. Of the 134 patients, 31 (23.1%) had ≥4 LN metastases. TTL ≥5.4×10⁴ copies/µl evaluated by receiver operator characteristic curve analysis was examined along with other clinicopathological variables. In the multivariate analysis, only TTL ≥5.4×10⁴ copies/µl was correlated with ≥4 LN metastases (odds ratio = 2.95, 95% confidence interval: 1.17-7.97, P=0.022). Therefore, TTL assessed by the OSNA assay has the potential to be a predictor of ≥4 LN metastases and it may be useful for the selection of patients with positive SLNs in whom ALND may be safely omitted.

[Regional treatment for axillary lymph node micrometastases of breast cancer]

In patients with breast cancer, axillary lymph node micrometastasis detection has been more frequent with a better definition since the introduction of the sentinel node procedure. In this review, we focus on pN1mi micrometastasis and review the literature in order to determine factors involved in making the decision of a regional treatment.

The extent of extracapsular extension may influence the need for axillary lymph node dissection in patients with T1-T2 breast cancer

BACKGROUND

Whether extracapsular extension (ECE) of tumor in the sentinel lymph node (SLN) is an indication for axillary lymph node dissection (ALND) in patients managed by American College of Surgeons Oncology Group Z0011 criteria is controversial. Here we examine the correlation between ECE in the SLN and disease burden in the axilla.

METHODS

Patients meeting Z0011 clinicopathologic criteria (pT1-2, cN0 with <3 positive SLNs) were selected from a prospectively maintained database (2006-2013). Chart review documented the presence and extent of ECE. Neoadjuvant chemotherapy patients were excluded. Comparisons were made by presence and extent (≤2 vs. >2 mm) of ECE.

RESULTS

Of 11,730 patients, 778 were pT1-2, cN0 with <3 positive SLNs without ECE, and 331 (2.8 %) had ECE. Of these, 180 had ≤2 mm and 151 had >2 mm of ECE. Patients with ECE were older (57 vs. 54 years; p = 0.001) and had larger (2.0 vs. 1.7 cm; p < 0.0001), multifocal (p = 0.006), hormone receptor-positive tumors (p = 0.0164) with lymphovascular invasion (p < 0.0001). Presence and extent of ECE were associated with greater axillary disease burden; 20 and 3 % of patients with and without ECE, respectively, had ≥4 additional positive nodes at completion ALND (p < 0.0001), and 33 % of patients with >2 mm ECE had ≥4 additional positive nodes at completion ALND, compared with 9 % in the <2 mm group (p < 0.0001). On multivariate analysis, >2 mm of ECE was the strongest predictor of ≥4 positive nodes at completion ALND (odds ratio 14.2).

CONCLUSIONS

Presence and extent of ECE were significantly correlated with nodal tumor burden at completion ALND, thus suggesting that >2 mm of ECE may be an indication for ALND or radiotherapy when applying Z0011 criteria to patients with metastases in <3 SLNs. ECE reporting should be standardized to facilitate future studies.

A risk score model predictive of the presence of additional disease in the axilla in early-breast cancer patients with one or two metastatic sentinel lymph nodes

BACKGROUND

Axillary lymph node dissection (ALND) in early-breast cancer patients with positive sentinel node (SLN+) may not always be necessary.

AIMS

To predict the finding of ≥1 metastatic axillary node in addition to SLN+(s); to discriminate between patients who would or not benefit from ALND.

METHODS

Records of 397 consecutive patients with 1-2 SLN+s receiving ALND were reviewed. Clinico-pathological features were used in univariate and multivariate analyses to develop a logistic regression model predictive of the risk of ≥1 additional axillary node involved. The discrimination power of the model was quantified by the area under the receiver operating characteristic curve (AUC) and validated using an independent set of 83 patients.

RESULTS

In univariate analyses, the risk of ≥1 additional node involved was correlated with tumor size, grade, HER-2 and Ki-67 over-expression, number of SLN+s. All factors, but Ki-67, retained in multivariate regressions were used to generate a predictive model with good discriminating power on both the training and the validation sets (AUC 0.73 and 0.75, respectively). Three patient groups were defined based on their risk to present additional axillary burden.

CONCLUSIONS

The model identifies SLN+-patients at low risk (≤15%) who could reasonably be spared ALND and those at high risk (>75%) who should receive ALND. For patients at intermediate risk, ALND appropriateness could be individually evaluated based on other clinico-pathological parameters.

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.

[Micrometastasis: biological entity and clinical impact?]

Micrometastases or sub-micrometastases can be detected by standard histopathological method sometimes associated with immunohistochemistry in lymph nodes, bone marrow and blood. The consequence of these small size involvement may be prognostic and therapeutic. Two factors are necessary to assess this kind of involvement: the rate of involvement of non-sentinel lymph node after axillary lymph node dissection and significative difference of survivals. The rate of involvement of non-sentinel lymph node in case of micrometastases or sub-micrometastases is different from the rate of involvement in case of no lymph node metastases (7 to 8%) or in case of macrometases (30 to 50%). Micrometastase is an important factor to determine the rate of involvement of non-sentinel lymph node, the overall or disease free survival and to assess the need of radiotherapy and chemotherapy. In conclusion, micrometastases and sub-micrometastases have a clinical impact even if complementary axillary lymph node dissection is still discussed.

Validation of the Louisville Breast Sentinel Node Prediction Models and a Proposed Modification to Guide Management of the Node Positive Axilla

The ACOSOG Z11 trial is rapidly changing use of axillary dissection, but it is not known how generalizable the Z11 results are. This study compares characteristics of the Z11 patients with the larger group of sentinel node-positive patients and evaluates two previously described Louisville algorithms to determine whether they might still be useful to predict extent of axillary node involvement and guide management of the axilla. The Yale Breast Center database was queried to calculate the Louisville prediction points for patients with a positive sentinel node and to compare the predicted with actual results. Of 1215 sentinel node biopsies performed between 2004 and 2010, 282 (23%) had at least one positive node. Thirty-one per cent of these patients would have been eligible for Z11. This group had much less axillary node involvement than the 69 per cent who were ineligible. The Yale data confirmed the accuracy of the two Louisville models and showed that tumor size, number of positive sentinel nodes, and proportion of positive sentinel nodes were all significant predictors. However, these results were much more robust if at least three sentinel nodes had been removed. The Z11 patients were clearly a good risk group. The data validate the two Louisville models and suggest that the models may be useful to select patients to avoid axillary dissection, both among the currently Z11-eligible and -ineligible populations. A modified algorithm is proposed in which all patients with a positive sentinel node have at least three total nodes removed.

Sentinel lymph node biopsy after neoadjuvant chemotherapy predicts pathological axillary lymph node status in breast cancer patients with clinically positive axillary lymph nodes at presentation

BACKGROUND

It is still controversial whether axillary lymph node (ALN) dissection (ALND) can be omitted after negative sentinel lymph node (SLN) biopsy (SLNB) in breast cancer (BC) patients with clinically positive ALNs at presentation treated with neoadjuvant chemotherapy (NAC). The study aim was to analyze whether SLNB could be useful in these patients.

METHODS

In a retrospective study, eligible patients were women with invasive BC with clinically positive ALNs at presentation, treated with NAC then a total or partial mastectomy, with an intraoperative histological examination of SLNs and non-SLNs suspicious for metastasis followed by ALND. Non-SLNs suspicious for metastasis were defined as hard or large nodes located in the same level of the axilla where clinically positive ALNs had been initially identified. The results of SLNB and clinicopathological characteristics were analyzed for correlation with pathological ALN status.

RESULTS

In a consecutive series of 105 women with 107 BC cases, 81 (75.7 %) had at least 1 SLN, and the remaining 26 (24.3 %) had at least 1 non-SLN suspicious for metastasis. The intraoperative (or final) histological examination of these nodes revealed that the false-negative (FN) rate and accuracy were 8.2 (or 6.3) % and 95.1 (or 96.3) %, respectively. Estrogen receptor status at presentation, pathological tumor response, lymphovascular invasion after NAC, and NAC regimen were correlated with pathological ALN status.

CONCLUSION

The histological examination of SLNs and that of non-SLNs suspicious for metastasis are useful for predicting pathological ALN status in BC patients with clinically positive ALNs at presentation who are treated with NAC.

Factors predicting the non-sentinel lymph node involvement in breast cancer patients with sentinel lymph node metastases

OBJECTIVE

In a significant proportion of patients, the sentinel lymph node (SLN) is the only involved axillary node. The goal of the present study was to identify predictive factors associated with a positive SLN and with a positive non-SLN in patients in whom axillary lymph node dissection (ALND) was performed.

METHODS

Data was reviewed for patients with T1-2 invasive breast cancer who underwent SLN biopsy with or without axillary dissection in a single institution between July 2000 and May 2010. The SLNs were examined by serial sectioning and H&E staining, and by cytokeratin immunostaining in suspicious cases.

RESULTS

Of 332 patients with SLNB, 134 had SLN positivity, and 116 of them further underwent completion axillary dissection. Patients with T2 tumors (OR=3.2; 95% CI, 1.74-5.58), or tumors with lymphovascular invasion (OR=8.0; 95% CI, 4.44-14.27), or invasive ductal cancer (OR=2.92; 95% CI, 1.1-8.0) were more likely to have a positive SLN. In patients with ALND, the non-SLN involvement rates were 10%, 11.5% and 50% in patients with isolated tumor cells (ITC), micrometastasis and macrometastasis, respectively. Finding of ITC or micrometastasis in SLNs (OR=0.28; 95% CI, 0.08-0.99) or presence of extracapsular invasion (ECI) in SLN (OR=0.24; 95% CI, 0.09-0.67) were the predictive factors of not having a non-SLN metastasis in logistic regression analysis.

CONCLUSIONS

These findings suggest further axillary surgery can be best omitted in patients with micrometastasis while validation of nomograms including factors such as ECI are still needed to be studied in patients with macrometastasis.

Factors that determine whether a patient receives completion axillary lymph node dissection after a positive sentinel lymph node biopsy for breast cancer in British Columbia

BACKGROUND

Completion axillary lymph node dissection (CALND) is recommended in the setting of positive sentinel lymph node biopsy (SLNB) but is associated with a higher rate of postoperative complications. In this study, the characteristics and outcomes of patients who did and did not have CALND are compared.

METHODS

We identified all patients with breast cancer with positive sentinel lymph nodes (SLNs) who did not have concurrent CALND from 2003 to 2006 using a prospectively collected database (British Columbia Cancer Breast Outcomes database) and retrospective chart review. Patient and tumour characteristics were compared between those who received CALND and those who did not.

RESULTS

Among 185 patients with positive SLNs identified by SLNB, 90 had a CALND and 95 had no further surgical therapy. Patients who did not receive CALND had more sentinel nodes removed (p < 0.001), a lower percentage of positive SLNs (p < 0.001) and lower pathologic N stage (p = 0.044) than those who did receive CALND. The size of the breast lesion, size of the largest SLN deposit, estrogen receptor status, grade, lymphovascular invasion, histology and multifocality were not significantly different between groups. Sixty-two percent of women who did not have CALND received radiation to the axilla. Postoperative complication rates (including lymphedema) were higher in the CALND group (21%) compared with the SLNB group (7%). The rates of locoregional recurrence (1% in both groups) and systemic metastases (6% in the CALND group v. 8% in the SLNB group) were similar at 36 months' follow-up.

CONCLUSION

Compared with women who had CALND, women who did not receive CALND had on average a lower N stage with 3 or more SLNs removed and less than 50% node positivity. Most of these women received radiation therapy to the axilla and had comparable recurrence rates to those who had CALND.

Tumor characteristics influencing non-sentinel lymph node involvement in clinically node negative patients with breast cancer

PURPOSE

The negative sentinel lymph node (SLN) biopsy avoids conventional axillary dissection in patients with breast cancer with clinically negative axilla. Despite negative SLN, there is a risk of leaving involved non-SLN behind in the axilla. We investigated the predictive power of tumor characteristics for non-SLN metastasis.

METHODS

Lymphatic mapping with blue dye method for SLN biopsy and level 1-2 axillary dissections were performed to establish axillary status in 59 patients with T1 and T2 breast cancer and clinically negative axilla. Tumor's characteristics were histopathologically established to assess their association with non-SLN metastasis.

RESULTS

The axilla was malignant in 23 (39%) patients. The SLN alone was metastatic in 10, both SLN and non-SLN in 9, and non-SLN alone in 4 (7%) patients. The false negative rate for SLN biopsy was 10% in our series. The rate of positive non-SLN was found as 0% in T1a-b, 19% in T1c, and 40% in T2 tumors (p=0.035). Lymphovascular invasion was positive in 14 (61%) patients with axillary metastasis (p<0.001), and in 10 (77%) patients with non-SLN involvement (p<0.001).

CONCLUSION

We concluded that there was a small risk of involved non-SLN despite negative SLN. Tumor size (near or greater than 2 cm) was significantly associated with non-SLN metastasis. Peritumoral lymphovascular invasion was a positive predictor of the metastatic involvement in non-SLNs.

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.

Implication of extracapsular invasion of sentinel lymph nodes in breast cancer: prediction of nonsentinel lymph node metastasis

BACKGROUND

Accurate intraoperative diagnosis of sentinel lymph node (SLN) metastases enables the selection of patients who require axillary lymph node dissection (ALND). However, many patients with positive SLN do not show metastasis to other axillary lymph nodes. In this study, we investigated the factors that may determine the likelihood of additional positive nodes in the axilla when metastasis is found in the SLN.

METHODS

SLN biopsy was performed on 276 patients with breast cancer with clinically negative nodes, of which 46 (16.6%) had positive SLNs and underwent ALND. Eleven (23.9%) of these 46 cases had additional metastasis in nonsentinel lymph nodes (NSLN). The clinical and pathological features of these cases were reviewed and statistical analysis was performed.

RESULTS

All cases of positive nodes in NSLN in our series had extracapsular invasion (ECI) at the metastatic SLNs. Furthermore, the absence of ECI of SLN was significantly associated with the absence of metastasis in the NSLN (P < 0.001). As contributing factors, the absence of lymphatic invasion at the primary tumor, primary tumor size (<2 cm) and foci size in the metastatic SLN fell short of reaching statistical significance. Other factors, including histological type, pathological grade, estrogen receptor status, HER2 status, and age, were not significantly associated with metastatic involvement of NSLN.

CONCLUSIONS

Our results suggest that the presence of ECI at metastatic SLNs is a strong predictor for residual disease in the axilla. These findings imply the possibility that ALND might be foregone in the treatment of patients with breast cancer without ECI at metastatic SLNs.

Predicting four or more metastatic axillary lymph nodes in patients with sentinel node-positive breast cancer: assessment of existent risk scores

BACKGROUND

Patients with metastases in four or more axillary lymph nodes (≥4+ALN) represent a subset of patients with breast cancer who are at increased risk of local recurrence and who benefit from postmastectomy radiation. Risk prediction models designed to identify such patients have been published by Rivers et al., Chagpar et al., and Katz et al. We sought to evaluate and compare the performance of these models in an independent patient population.

METHODS

We reviewed 454 patients with breast cancer with one to three positive sentinel lymph nodes who underwent completion axillary lymph node dissection at our institution. Each of the three published models was applied to our sample as described in the respective publications. The models' performances were analyzed with the Hosmer-Lemeshow goodness-of-fit test and with the area under the curve (AUC). Sensitivity, specificity, and false-negative percentages were calculated for clinically meaningful cutoff points of each score.

RESULTS

Of 454 eligible patients, 87 (19.2%) had four or more positive axillary nodes. The Rivers, Chagpar, and Katz models demonstrated good calibration in our population based on the Hosmer-Lemeshow test (p = 0.82, p = 0.73, p = 0.71, respectively). Assessment of discriminatory ability for the models resulted in AUCs of 0.81, 0.73, and 0.81, respectively.

CONCLUSIONS

The Rivers and Katz models performed well in our patient population and may be clinically useful to predict patients with ≥4+ALN. However, their clinical utility is limited by the current controversy surrounding the use of postmastectomy radiation for all node-positive patients.

Prognostic value of nodal ratios in node-positive breast cancer: a compiled update

The number of positive axillary nodes is a strong prognostic factor in breast cancer, but is affected by variability in nodal staging technique yielding varying numbers of excised nodes. The nodal ratio of positive to excised nodes is an alternative that could address this variability. Our 2006 review found that the nodal ratio consistently outperformed the number of positive nodes, providing strong arguments for the use of nodal ratios in breast cancer staging and management. New evidence has continued to accrue confirming the prognostic significance of nodal ratios in various worldwide population settings. This review provides an updated summary of available data, and discusses the potential application of the nodal ratio to breast cancer staging and prognostication, its role in the context of modern surgical techniques such as sentinel node biopsy, and its potential correlations with new biologic markers such as circulating tumor cells and breast cancer stem cells.

Axillary lymph node dissection can be avoided in women with breast cancer with intraoperative, false-negative sentinel lymph node biopsies

BACKGROUND

It is currently unclear which patients with breast cancer with sentinel lymph node (SLN) metastases do not need axillary lymph node dissection (ALND).

PATIENTS AND METHODS

A cohort of 1,132 women who had unilateral invasive breast cancer with clinically negative nodes or nodes suspicious for metastasis, were intraoperatively diagnosed as having negative SLNs, and did not undergo an immediate ALND. Our intraoperative histological investigation uses H&E staining of a frozen section from a maximum cut surface of each SLN. Of these 1,132 women, 132 (11.7%) were postoperatively diagnosed as having positive SLNs, which classifies them as having an intraoperative, false-negative SLN biopsy (SLNB). Patient and tumor characteristics, treatment methods, and the prognoses of these patients were investigated and compared with the remaining 1,000 patients who were negative for SLNB.

RESULTS

Of the 132 patients with intraoperative, false-negative SLNB, none underwent a further ALND. With a median follow-up period of 58.1 months, none of these patients exhibited recurrence in the axillary nodes. Their recurrence-free survival rates were not statistically different from those of patients with negative SLNB.

CONCLUSIONS

ALND can be avoided in most patients with breast cancer with intraoperative, false-negative SLNB.

Positive sentinel lymph node biopsy predicts the number of metastatic axillary nodes of breast cancer

It remains to be clarified whether a positive sentinel lymph node biopsy (SLNB) can predict the number of metastatic axillary nodes. This study examined a consecutive series of women with unilateral invasive breast cancer who underwent axillary lymph node dissection after an intra-operative positive SLNB. The numbers of positive and negative sentinel lymph nodes (SLNs) were analyzed for a likelihood of pN1a, pN2a, and pN3a diseases as per the UICC TNM classification. Of the 368 study patients, 165 (45%) had one positive SLN and one or more negative SLNs. This result represented the most common combination of positive and negative SLNs. It was also the most predictive indicator (93%) of pN1a disease and the least predictive indicator (7% or 0%) of pN2a or pN3a disease, respectively. The numbers of positive and negative SLNs can predict the number of metastatic axillary nodes in breast cancer patients.

Completion of axillary dissection for a positive sentinel node: necessary or not?

Sentinel node excision has been widely accepted as the initial surgical step for evaluating the axilla for metastatic breast cancer. When the nodes are positive, the standard of care is to complete the axillary node dissection, a more extended procedure that carries an increased risk for morbidity. This article reviews data from sentinel lymph node trials, case series reports of outcomes when axillary node dissection was not performed in the setting of positive sentinel nodes, models for predicting the status of nonsentinel nodes, and the morbidity associated with axillary operations. Despite an approximate 10% false-negative rate, early results indicate that there is a much lower local recurrence rate after sentinel node excision alone and that systemic therapy may sterilize the axilla. In selected patients, it may be appropriate to forgo an axillary node dissection, although there are no randomized clinical trial data to support or refute this suggestion.

Lymphovascular invasion and lobular histology are associated with increased incidence of isolated tumor cells in sentinel lymph nodes from early-stage breast cancer patients

BACKGROUND

Isolated tumor cells (ITC) are more likely to be identified when serial sectioning and immunohistochemical staining are used to evaluate sentinel lymph nodes (SLN). Our goal was to identify clinicopathologic features associated with ITC in patients undergoing sentinel lymph node dissection (SLND).

METHODS

We reviewed clinicopathologic data for 3557 patients with no clinical evidence of lymph node metastases undergoing SLND between November 1993 and March 2007. Patients were staged according to the 6th edition of the American Joint Committee on Cancer staging system, with metastasis <or=.2 mm classified as ITC.

RESULTS

A SLN was identified in 3475 patients (97.7%), including 2518 (72.4%) with negative nodes and 169 (4.9%) with ITC. A statistically significant association existed between lobular histology and the identification of ITC; 13.6% of patients with ITC had lobular histology versus 7.3% of patients with a negative SLN (P = .003). The presence of lymphovascular invasion (LVI) was also associated with ITC; 18.3% of patients with ITC had LVI in the primary tumor versus 8.5% of patients with a negative SLN (P < .001). No difference existed between patients with and without ITC with respect to T stage, grade, estrogen receptor, progesterone receptor, HER2/neu status, or biopsy method.

CONCLUSION

The association between ITC and LVI, a known predictor of poor outcome, suggests ITC may have clinical relevance. The relationship between lobular histology and ITC is consistent with the known pattern of lobular metastases, which frequently present as small foci requiring immunohistochemistry for detection. Longer follow-up is needed to determine whether ITC have prognostic significance.

Factors predicting additional disease in the axilla in patients with positive sentinel lymph nodes after neoadjuvant chemotherapy

BACKGROUND

The utility of sentinel lymph node (SNL) biopsy (SLNB) as a predictor of axillary lymph node status is similar in patients who receive neoadjuvant chemotherapy and patients who undergo surgery first. The authors of this study hypothesized that patients with positive SLNs after neoadjuvant therapy would have unique clinicopathologic factors that would be predictive of additional positive non-SLNs distinct from patients who underwent surgery first.

METHODS

One hundred four patients were identified who received neoadjuvant chemotherapy, had a positive SLN, and underwent axillary dissection between 1997 and 2005. At the time of presentation, 66 patients had clinically negative lymph nodes by ultrasonography, and 38 patients had positive lymph nodes confirmed by fine-needle aspiration. Eighteen factors were assessed for their ability to predict positive non-SLNs using chi-square and logistic regression analysis with a bootstrapped, backwards elimination procedure. The resulting nomogram was tested by using a patient cohort from another institution.

RESULTS

Patients with clinically negative lymph nodes at presentation were less likely than patients with positive lymph nodes to have positive non-SLNs (47% vs 71%; P=.017). On multivariate analysis, lymphovascular invasion, the method for detecting SLN metastasis, multicentricity, positive axillary lymph nodes at presentation, and pathologic tumor size retained grouped significance with a bootstrap-adjusted area under the curve (AUC) of 0.762. The resulting nomogram was validated in the external patient cohort (AUC, 0.78).

CONCLUSIONS

A significant proportion of patients with positive SLNs after neoadjuvant chemotherapy had no positive non-SLNs. The use of a nomogram based on 5 predictive variables that were identified in this study may be useful for predicting the risk of positive non-SLNs in patients who have positive SLNs after chemotherapy.

Management of the axilla after the finding of a positive sentinel lymph node: a proposal for an evidence-based risk-adapted algorithm

Axillary lymph node dissection after the finding of a positive sentinel lymph node is a common clinical practice. A review is performed for the efficacy and morbidity of axillary lymph node dissection, the rationale for nonsurgical management of the axilla, and the efficacy, technical limitations, and toxicity of axillary radiation therapy; a management algorithm is then proposed based upon currently available prediction tools.

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.

Sentinel node positive breast cancer patients who do not undergo axillary dissection: are they different?

BACKGROUND

Little data address outcome in patients with sentinel lymph node (SN) metastases without completion axillary lymph node dissection (CALND). This study was designed to assess locoregional recurrence in patients with positive SNs who did not undergo CALND.

METHODS

An IRB-approved, retrospective chart review was conducted on breast cancer patients with a positive SN. Follow-up information on outcomes was obtained via mailed questionnaires and chart review. Comparative analyses were performed between patients who did and did not undergo CALND after a positive sentinel lymph node biopsy.

RESULTS

From November 1998 to June 2004, 625 breast cancer patients had a positive sentinel lymph node biopsy. One-hundred and eighteen patients with < or = 0.2 mm nodal metastases (N0i+) were excluded from the study. Of the remaining 507 patients, 421 underwent CALND and 86 did not. In comparison to patients who had CALND, patients who did not undergo CALND had smaller primary tumors (2 vs 2.6 cm, P = .0007) and were more likely to have a single positive sentinel node (92% vs 77%, P = .002). The metastasis size of the sentinel node was smaller compared to patients who underwent axillary dissection (1.7 vs 6.4 mm, P < .0001). Mean predicted probability of nonsentinel node metastasis in patients who did not undergo CALND was 20% compared to 47% in patients who did (P < .0001). During a median follow-up of 30 months, there were no axillary recurrences.

CONCLUSIONS

These data confirm that patients who have a positive sentinel node biopsy and do not undergo CALND have a lower risk profile for axillary disease. In this lower risk subset, axillary treatment may not be necessary.

Comparison of two models for the prediction of nonsentinel node metastases in breast cancer

BACKGROUND

It is debated whether all patients with a positive sentinel node dissection (SLND) should be submitted to axillary lymph node dissection (ALND). Models have been developed to estimate the likelihood of nonsentinel node (non-SLN) metastases.

METHODS

The accuracy of the Memorial Sloan-Kettering Cancer Center (MSKCC) nomogram and MD Anderson scoring system for the prediction of non-SLN status was tested in a consecutive series of 186 SLN-positive breast cancer patients. A multivariate analysis was performed to assess which parameters independently predicted the presence of non-SLN metastases.

RESULTS

The predictive accuracy of the MSKCC nomogram measured by the receiver operating characteristic curve was 0.71, and it was best in patients with <10% risk of non-SLN metastases (sensitivity 100% and specificity 96%). The MD Anderson score predicted non-SLN involvement with low accuracy because it classified 85% of the patients in the intermediate-risk groups. Only SLN macrometastases and tumor multifocality independently predicted non-SLNs involvement.

CONCLUSIONS

The MSKCC nomogram can help individualize the surgical treatment of SLN-positive breast cancer when the likelihood of further axillary involvement is low or surgical risks are higher.

Lymphovascular invasion, as a prognostic marker in patients with invasive breast cancer

PURPOSE

The markers of prognosis are used to predict the clinical course of disease and the outcome for patients with invasive breast cancer. Our aim is to investigate the relationship of peritumoural lymphovascular invasion (LVI) with well-known prognostic markers.

PATIENTS AND METHODS

Eighty-one surgically treated patients with invasive breast cancer were evaluated in this study during a mean follow-up period of 46 months (12-72). The patient's age (menopausal status), tumour size, nuclear grade, axillary lymph node involvement, and hormone receptor status were determined as markers of the prognosis. The relationship of LVI with these markers was established.

RESULTS

Except for menopausal status (p = 0.25) a close relationship was found between the presence of LVI and studied prognostic factors. LVI was positive in 29% of T1, 54% of T2 (p = 0.028) and 100% of T3 tumours (p = 0.002). The rate of LVI (+) has increased gradually as 0%, 38% and 77% (p = 0.001) with grades 1, 2 and 3 respectively. Positive LVI has been determined in 85% (p < 0.0001) and 73% (p = 0.0004) of oestrogen and progesterone receptor negative tumours respectively. LVI was present in 14% and 73% (p < 0.0001) of patients with negative and positive axilla respectively. Metastatic cancer caused mortality in seven patients of whom 86% had more than four involved axillary nodes, and 100% LVI (+).

CONCLUSION

The high rate of positive LVI shows a close relationship with known markers of poor prognosis. The presence of LVI can predict a worse outcome for patients with invasive breast cancer. LVI may be used as an indicator of aggressive behaviour, metastatic ability (nodal and systemic) of the primary malignancy.

Predicting Patients at Low Probability of Requiring Postmastectomy Radiation Therapy

BACKGROUND

Postmastectomy radiation therapy (PMRT) is recommended for patients with four or more positive lymph nodes (LN+). Given the ramifications of PMRT for immediate reconstruction, we sought to create a model using preoperative and intraoperative factors to predict which patients with a positive sentinel lymph node will have less than four LN+.

METHODS

The database from a prospective multicenter study of 4,131 patients was used for this analysis. Patients with one to three positive sentinel lymph nodes (SLN) and tumors < 5 cm (n = 1,133) in size were randomly divided into a training set (n = 580) and a test set (n = 553). Multivariate logistic regression was used on the training set to create a prediction rule that was subsequently validated in the test set.

RESULTS

Median patient age was 57 (range, 27-100) years, and median tumor size was 2.0 (range, 0.2-4.8) cm. In the training set, factors associated with having four or more LN+ on multivariate analysis were: tumor size [odds ratio (OR) = 2.087; 95% confidence interval (CI): 1.307-3.333, P = 0.002), number of positive SLN (P < 0.0005), and proportion of positive SLN (OR = 3.602; 95% CI: 2.100-6.179, P < 0.005). A predictive model was established with a point assigned to each positive SLN, T2 (vs. T1), and if proportion of positive SLN was > 50%, for a maximum of five points. In both the training and test sets, patients with one point had a low probability of having four or more LN+ (3.8% and 3.3%, respectively).

CONCLUSION

Tumor size, number of positive SLN, and the proportion of positive SLN influence whether patients will have four or more LN+. A simple model can predict the probability of requiring PMRT.