Microscopic Extracapsular Extension in Sentinel Lymph Nodes Does Not Mandate Axillary Dissection in Z0011-Eligible Patients

Size of Extranodal Extension in the Sentinel Lymph Node as a Predictor of Prognosis in Early-Stage Breast Cancer

INTRODUCTION

The presence of extranodal extension (ENE) in sentinel lymph nodes (SLNs) can predict non-SLN metastases in breast cancer (BC) patients; however, the prognostic relevance of its extent remains controversial. The purpose of this study was to examine the predictive role of ENE in SLNs measured by its widest dimension (WD), highest dimension (HD), and the WD/HD ratio for non-SLN involvement, overall, and disease-free survival (OS, DFS) in cT1-2N0 BC patients with positive SLNs.

MATERIALS AND METHODS

A total of 511 women with cT1-2N0 BC and positive SLNs undergoing axillary lymph node dissection were retrospectively enrolled. The associations of ENE's WD, HD, and WD/HD ratio with non-SLN metastases, 5-year OS, and DFS were established through a multivariable modeling approach.

RESULTS

SLNs were ENE-positive in 149 (29.16%) participants, and 133 (26.03%) had non-SLN metastases. During the median 60 (16-60)-month follow-up, 69 (13.50%) patients experienced recurrences, and 62 (12.13%) died. The numbers of SLNs, non-SLNs, and total axillary LNs involved differed between the ENE-negative and ENE-positive groups, as well as between the WD/HD ≤ 1.2 and WD/HD > 1.2 subgroups (all P-values were < .001). Multivariable analyses showed significant associations of the WD/HD ratio > 1.2 with non-SLN involvement, OS, and DFS (P-values were .003, < .001, and .005, respectively).

DISCUSSION

Despite no predictive value of ENE's WD and HD, the WD/HD ratio > 1.2 was an independent predictor of non-SLN involvement, mortality, and recurrence. ENE's WD/HD ratio could be a valuable indicator for cT1-2N0 BC individuals with positive SLNs for whom further axillary treatment may be beneficial.

Long-Term Survival Outcomes and Risk Factors for Axillary and Locoregional Recurrence in Japanese Patients with Sentinel Node-Positive Breast Cancer Treated in Accordance with the ACOSOG Z0011 Strategy

INTRODUCTION

In 2018, we reported the results of a study to assess the feasibility of applying the ACOSOG Z0011 criteria to Japanese patients with early-stage breast cancer (median follow-up, 3 years). Their results over the longer term can now be presented. Risk factors for axillary and locoregional recurrence in Z0011-eligible patients are unknown.

METHODS

Long-term survival outcomes were investigated by analyzing data from patients enrolled in the feasibility study. Data from the feasibility study patients, and from patients eligible for the Z0011 strategy after its introduction into clinical practice, were subjected to multivariate logistic regression analysis to identify risk factors for axillary and locoregional recurrence.

RESULTS

Regarding long-term outcomes for the feasibility study patients (n = 189), distant disease-free survival rates at 5 and 7 years were 90.4 ± 2.1% and 85.9 ± 2.6%, respectively, and overall survival rates at 5 and 7 years were 97.3 ± 1.2% and 95.3 ± 1.7%, respectively. Analysis of data from these patients plus the 93 who received Z0011 in clinical practice (total, n = 282) identified the following independent risk factors for axillary recurrence: absence of high axillary tangential irradiation (OR, 5.87 [95% CI, 1.09-31.35], p = 0.04) and number of positive sentinel lymph nodes (OR, 4.65 [95% CI, 1.11-19.48], p = 0.04). Only high Ki67 labeling index (OR, 5.92 [95% CI, 1.31-26.70], p = 0.02) was identified as an independent risk factor for locoregional recurrence.

CONCLUSION

Long-term survival outcome results of the feasibility study show that the Z0011 strategy can be used to treat Japanese patients with early-stage breast cancer. Our findings regarding risk factors suggest that high axillary tangent irradiation is necessary for the prevention of axillary recurrence and that irradiation, including of the regional lymph nodes, should be considered, especially in patients with high Ki67 index values.

Is my patient an appropriate candidate for sentinel node biopsy? Less axillary surgery, for the right patients. Critical review and grades of recommendation

INTRODUCTION

While general conclusions of historical trials are widely recognized, the nuances regarding precise indications of Sentinel Node Biopsy (SNB) in breast cancer in complex clinical scenarios often remain a source of debate and require further elucidation.

METHODS

Two reviewers (JFB and GNM) independently searched electronic databases for studies including SNB as the main intervention. Filters were applied to retrieve only clinical trials (randomized or experimental non-randomized); non-oncological outcomes were excluded. The selected studies were considered to construct a narrative review focused on inclusion criteria and survival outcomes, followed by recommendations.

RESULTS

Fourteen (n = 14) trials were selected, including eleven (n = 11) randomized trials for upfront surgery, and three (n = 3) single-group clinical trials for surgery following neoadjuvant therapy. All trials for upfront surgery provided long-term survival data for SNB, that was equivalent or non-inferior to axillary dissection, in tumors without palpable adenopathy (caution for larger T3 and T4 tumors) - Grade of recommendation: A. In tumors up to 5 cm, complete axillary dissection is not necessary if up to two sentinel nodes are positive for macrometastasis, and radiation therapy is planned - Grade of recommendation: A. If there are more than two sentinel nodes positive for macrometastasis, or a positive node other than the sentinel one, complete axillary dissection is recommended - Grade of recommendation: A. Following neoadjuvant chemotherapy, considering 10% as an acceptable false negative rate, SNB might be offered for cN0 patients who have remained negative, and for cN1 (caution for cN2) patients become clinically negative; complete axillary dissection might not be necessary if at least two sentinel lymph nodes are retrieved, and there is no residual disease - Grade of recommendation: B.

CONCLUSION

SNB can be performed in most cases of clinically negative nodes. After neoadjuvant chemotherapy, SNB is feasible and may have acceptable performance for cN0 and cN1 tumors, although prospective survival data is still awaited.

Update on Sentinel Lymph Node Methods and Pathology in Breast Cancer

Breast cancer stands out as the most commonly diagnosed cancer among women globally. Precise lymph node staging holds critical significance for both predicting outcomes in early-stage disease and formulating effective treatment strategies to control regional disease progression in breast cancer patients. No imaging technique possesses sufficient accuracy to identify lymph node metastases in the early stages (I or II) of primary breast cancer. However, the sentinel node procedure emerges as a valuable approach for identifying metastatic axillary nodes. The sentinel lymph node is the hypothetical first lymph node or group of nodes draining a cancer. In case of established cancerous dissemination, it is postulated that the sentinel lymph nodes are the target organs primarily reached by metastasizing cancer cells from the tumor. The utilization of the sentinel node technique has brought about changes in the assessment of lymph nodes. It involves evaluating the sentinel node during surgery, enabling prompt lymph node dissection when the sentinel node procedure is positive. Additionally, histological ultra-stratification is employed to uncover occult metastases. This review aims to provide an update of this valuable technique, with focus on the practical aspects of the procedure and the different histological protocols of sentinel node evaluation in breast cancer.

Pathologic Exploration of the Axillary Soft Tissue Microenvironment and Its Impact on Axillary Management and Breast Cancer Outcomes

PURPOSE

Axillary soft tissue (AXT) involvement with tumor cells extending beyond the positive lymph node (LN+) and extracapsular extension (ECE) has been overlooked in breast pathology specimen analysis.

MATERIALS AND METHODS

We analyzed 2,162 LN+ patients, dividing them into four groups on the basis of axillary pathology: (1) LN+ only, (2) LN+ and ECE only, (3) LN+ and AXT without ECE, and (4) LN+ with both AXT and ECE. The primary end points were 10-year locoregional failure (LRF), the 10-year axillary failure, and 10-year distant metastasis rates. Multivariable Cox models, accounting for clinical factors, were fitted using the entire cohort, and subgroups analyses were conducted.

RESULTS

The median follow-up was 9.4 years. The 10-year distant metastasis incidence was 42% for LN + AXT + ECE, 23% for both LN + AXT and LN + ECE only, and 13% for LN+ only. The 10-year axillary failure rates were 4.5% for LN + AXT + ECE, 4.6% for LN + AXT, 0.8% for LN + ECE only, and 1.6% for LN+ only. The 10-year LRF rates were 14% for LN + AXT + ECE, 10% for LN + AXT, 5.7% for LN + ECE only, and 6.2% for LN+ only. Multivariable analysis revealed that AXT was significantly associated with distant metastasis (hazard ratio [HR], 1.6; P < .001), locoregional failure (HR, 2.3; P < .001), and axillary failure (HR, 3.3; P = .003). Subgroup analyses showed that regional LN radiation (RLNR) improved locoregional tumor outcomes with AXT, ECE, or both (HR, 0.5; P = .03). Delivering ≤50 Gy to the axilla in the presence of AXT/ECE increased axillary failure (HR, 3.0; P = .04). Moreover, when delivering RLNR, axillary LN dissection could be de-escalated to sentinel node biopsy even in the presence of features such as AXT or ECE without significantly increasing any failure outcome: (HR, 1.0; P = .92) for LRF, (HR, 1.1; P = .94) axillary failure, and (HR, 0.4; P = .01) distant metastasis.

CONCLUSION

Routine reporting of axillary tissue involvement, beyond LNs and ECE, is crucial in predicting breast cancer outcomes. Ruling out the presence of AXT is imperative before any form of axillary de-escalation, especially RLNR omission.

Non-sentinel lymph node metastases risk factors in patients with breast cancer with one or two sentinel lymph node macro-metastases

Approximately 59 % of patients with breast cancer with one or two sentinel lymph nodes (1-2 SLN) macrometastases do not benefit from axillary lymph node dissection (ALND), which may also incur morbidities. It is necessary to evaluate the association between various clinicopathological characteristics and non-sentinel lymph node metastases (non-SLNM) in patients with breast cancer with 1-2 SLN macrometastases, and determine whether they 1-2 should avoid ALND. Eight electronic literature databases (PubMed, Embase, Web of Science, Cochrane Library, China National Knowledge Infrastructure, Chinese Scientific Journal, Wanfang, and Chinese Biomedical Literature) were searched from their inception to June 30, 2023, and two reviewers independently extracted the data and assessed the risk of bias. Association strength was summarized using odds ratios (OR) and 95 % confidence intervals (CI). Heterogeneity was accounted for using a subgroup analysis. Publication bias was evaluated using funnel plots and Egger's test. There were 25 studies with 8021 participants, and 27 potential risk factors were evaluated. The risk factors for non-SLNM in patients with 1-2 SLN macrometastatic breast cancer include the following: factors of primary tumor: multifocality (OR (95 % CI (2.63 (1.96, 3.54))), tumor size ≥ T2 (2.64 (2.22, 3.14)), tumor localization (upper outer quad) (2.06 (1.23, 3.43)), histopathological grade (G3) (2.45 (1.70, 3.52)), vascular invasion (VI) (2.60 (1.35, 4.98)), lymphovascular invasion (LVI) (2.87 (1.80, 4.56)), perineural invasion (PNI) (3.16 (1.18,8.43)). Factors of lymph nodes: method of SLNs detected (blue dye) (3.85 (1.54, 9.60)), SLN metastasis ratio ≥0.5 (2.79 (2.24, 3.48)), two positive SLNs (3.55, (2.08, 6.07)), zero negative SLN (3.72 (CI 2.50, 4.29)), extranodal extension (ENE) (4.69 (2.16, 10.18)). Molecular typing: Her-2 positive (2.08 (1.26, 3.43)), Her-2 over-expressing subtype (1.83 (1.22, 2.73)). Factors of examination/inspection: axillary lymph nodes (ALNs) positive on imaging (3.18 (1.68, 6.00)), cancer antigen 15-3 (CA15-3) (4.01 (2.33,6.89)), carcinoembryonic antigen (CEA) (2.13 (1.32-3.43)). This review identified the risk factors for non-SLNM in patients with 1-2 SLN macrometastatic breast cancer. However, additional studies are needed to confirm the above findings owing to the limited number and types of studies included.

Contemporary approaches to the axilla in breast cancer

Over the past decade, axillary management in breast cancer has fundamentally shifted. The former notion that any degree of axillary nodal involvement warrants axillary lymph node dissection (ALND) has been challenged. Following publication of the ACOSOG Z0011 trial, national trends demonstrated significant reductions in ALND performance. Axillary radiotherapy in lieu of ALND is a consideration for select patients with a positive sentinel lymph node, while ongoing studies are investigating the role of adjuvant regional radiotherapy in women with positive nodes prior to neoadjuvant chemotherapy. Efforts toward de-escalation of axillary surgery continue to evolve, as do the indications for sentinel node biopsy omission in select subsets of patients. This review highlights the recent advances and neoteric approaches to local therapy of the axilla in breast cancer.

Anatomical site and size of sentinel lymph node metastasis predicted additional axillary tumour burden and breast cancer survival

AIMS

Sentinel lymph node (SLN) biopsy is the current standard assessment for tumour burden in axillary lymph node (ALN). However, not all SLN+ patients have ALN metastasis. The prognostic implication of SLN features is not clear. We aimed to evaluate predictive factors for ALN metastasis and the clinical value of SLN features.

METHODS AND RESULTS

A total of 228 SLN+ and 228 SLN- (with matched year and grade) cases were included. Clinicopathological features in SLN, ALN and primary tumours, treatment data and survival data were analysed according to ALN status and outcome. Except for larger tumour size and the presence of LVI (both P < 0.001), no significant differences were found in SLN- and SLN+ cases. Only 31.8% of SLN+ cases with ALN dissection had ALN metastasis. The presence of macrometastases (MaM), extranodal extension (ENE), deeper level of tumour invasion in SLN and more SLN+ nodes were associated with ALN metastasis (P ≤ 0.025). Moreover, isolated tumour cells (ITC) and level of tumour invasion in SLN were independent adverse prognostic features for disease-free survival and breast cancer-specific survival, respectively. Interestingly, cases with ITC located in the subcapsular region have better survival than those in cortex (OS: χ²  = 4.046, P = 0.044).

CONCLUSIONS

Our study identified features in SLN, i.e. the level of tumour invasion at SLN and tumour size in SLN as useful predictors for both ALN metastasis and breast cancer outcome. The presence of ITC, particularly those with a deeper invasion in SLN, portended a worse prognosis. Proper attention should be taken for their management.

Intraoperative Sentinel Node Fine-Needle Aspiration Biopsy as a Substitute for Whole Sentinel Node Excisional Biopsy in Breast Cancer Patients. Initial Report

INTRODUCTION

Sentinel Node Biopsy (SNB) is the choice procedure for axillary staging in Breast Cancer. Following the ACOSOG Z11 trial, axillary dissection is advised only in patients with more than 2 positive SNs. We aimed at exploring palpation-guided, intraoperative fine-needle aspiration biopsy of the SN as a replacement for whole SN excision in node-negative BC patients to minimize side-effects.

PATIENTS AND METHODS

We included 80 patients with BC undergoing SNB between December 2020 and May 2022. After identification of the SN, the breast surgeon performed SN-FNAB. Results were compared with definitive pathological assessment. ResultsDiagnostic yield was 80%, including a "learning curve." 58 of 64 patients with suitable samples tested negative. In this group, the Negative Predictive Value was 77.6% (IC 64.7%-87.5 %). If micro metastasis is disregarded, the NPV would increase to 86.2% (IC 74.6%-93.9%). If we accept the Z11 criterion for axillary dissection, the NPV would rise to 100%. Six patients had a positive SN-FNAB. They were all confirmed as having macro metastatic-positive SNs at the final pathological assessment, and 3 of them also displayed extra nodal extension (ENE).

CONCLUSION

We believe that intraoperative SN-FNAB is highly accurate for swiftly depicting both low axillary tumor burden/negative cases, in whom axillary dissection is to be omitted, as well as high axillary tumor burden cases.

Extranodal extension, an international survey on its evaluation and reporting in breast cancer patients

Lymph node metastasis is the most important prognostic factor for breast cancer patients. In addition to the number of nodes involved and the largest metastatic focus, extranodal extension (ENE) is also used to subclassify breast cancer patients into different risk groups. More recently, pathologists are required to report the size/extent of ENE per the new CAP guideline, as it seems to be associated with more axillary nodal burden and/or a worse prognosis. Although the definition of ENE is largely understood and agreed upon among pathologists around the world, evaluation and reporting for the size of ENE are not. To understand current practice, we conducted an international survey among pathologists who are interested in breast pathology. A total of 70 pathologists responded. The results showed that (1) 98% of the participants reported the presence or absence of ENE and 61% also reported the size of ENE in millimeter (mm). (2) There was no uniform method of measuring the size of ENE; 47% measured the largest dimension regardless of orientation, while 30% measured the largest perpendicular distance from the capsule. (3) The most common factors affecting the accuracy in diagnosis of ENE are the presence of lymphovascular invasion (LVI), lack of capsule integrity, and the presence of fatty hilar or fatty replacement of a lymph node. (4) 71% felt that the H&E stain is adequate to evaluate ENE, deeper levels and IHC analysis for vascular and cytokeratin markers can be helpful if needed. (5) 75% agreed that there is an urgent need to standardize the measurement and reporting for ENE. Our survey highlights the variation in ENE evaluation and the need for its standardization in breast cancer patients with axillary node metastasis.

Regional Nodal Management in the Setting of Up-Front Surgery

Historically, axillary lymph node dissection was considered necessary for regional control of breast cancer. Moreover, nodal status was the major determinant of the need for chemotherapy. The increased use of systemic therapy coupled with expanding indications for nodal irradiation has led to interest in optimizing patient outcomes by leveraging the local control benefits of radiotherapy and systemic therapy to decrease the extent of surgery. A series of landmark surgical and radiotherapeutic trials has demonstrated low rates of disease recurrence with concomitant improvements in treatment-associated lymphedema and quality of life with the use of sentinel node biopsy and nodal irradiation as opposed to complete axillary dissection in the management of node positive breast cancer. This chapter will explore the evolution of regional nodal management, culminating in current approaches to tailored patient selection for axillary lymph node dissection, sentinel lymph node biopsy, and adjuvant regional nodal irradiation.

Update on sentinel node pathology in breast cancer

Pathologic examination of the sentinel lymph nodes (SLNs) in patients with breast cancer has been impacted by the publication of practicing changing trials over the last decade. With evidence from the ACOSOG Z0011 trial to suggest that there is no significant benefit to axillary lymph node dissection (ALND) in early-stage breast cancer patients with up to 2 positive SLNs, the rate of ALND, and in turn, intraoperative evaluation of SLNs has significantly decreased. It is of limited clinical significance to pursue multiple levels and cytokeratin immunohistochemistry to detect occult small metastases, such as isolated tumor cells and micrometastases, in this setting. Patients treated with neoadjuvant therapy, who represent a population with more extensive disease and aggressive tumor biology, were not included in Z0011 and similar trials, and thus, the evidence cannot be extrapolated to them. Recent trials have supported the safety and accuracy of sentinel lymph node biopsy (SLNB) in these patients when clinically node negative at the time of surgery. ALND remains the standard of care for any amount of residual disease in the SLNs and intraoperative evaluation of SLNs is still of value for real time surgical decision making. Given the potential prognostic significance of residual small metastases in treated lymph nodes, as well as the decreased false negative rate with the use of cytokeratin immunohistochemistry (IHC), it may be reasonable to maintain a low threshold for the use of cytokeratin IHC in post-neoadjuvant cases. Further recommendations for patients treated with neoadjuvant therapy await outcomes data from ongoing clinical trials. This review will provide an evidence-based discussion of best practices in SLN evaluation.

Survival and recurrence with or without axillary dissection in patients with invasive breast cancer and sentinel node metastasis

To evaluate overall survival and locoregional recurrence between patients with invasive breast tumours and sentinel node metastasis undergoing sentinel lymph node dissection (SLND) alone and those undergoing complete axillary lymph node dissection (ALND). In this retrospective cohort study, we reviewed the medical records of patients with invasive breast carcinoma who underwent lumpectomy at a public university hospital in Brazil between 2008 and 2018. We evaluated the overall survival and the locoregional recurrence using Kaplan-Meier and Cox regression analyses, respectively. Overall, 97 participants who underwent lumpectomy were enroled; 41 in the ALND group, and 56 in the SLND group, according to Z0011 criteria. Only 17% of the patients in the ALND group had an additional biopsy-proven axillary disease, and 83% were treated with complete dissection unnecessarily. The 5-year survival rates were 80.1% and 87.5% for SLND and ALND, respectively (p = 0.376). Locoregional recurrence was rare (1.7% and 7.3% in the SLND and ALND, respectively; p = 0.3075). Overall survival and locoregional recurrence were similar between the two groups. The de-escalation of ALND to SLND in women with metastasis in the sentinel lymph node treated with conservative surgery and radiotherapy that meet the Z0011 criteria is feasible even in developing countries.

The Attitudes of Brazilian Breast Surgeons on Axillary Management in Early Breast Cancer-10 Years after the ACOSOG Z0011 Trial First Publication

PURPOSE

To evaluate the impact of the ACOSOG Z0011 trial on axillary breast cancer surgery management in Brazil following publication of that study (2010) and again in 2020.

PATIENTS AND METHODS

A survey of members of the Brazilian Society of Mastology.

RESULTS

Of 1627 breast surgeons, 799 (49.1%) completed and returned the questionnaire. For patients with the Z11 inclusion criteria, following detection of a positive sentinel lymph node (SLN), axillary dissection (AD) was recommended by 99.2% of respondents before publication of the study, 47.5% in 2010 and 18.5% in 2020 (p < 0.001). In breast-conserving surgery, if there were micro-metastases, 2.6% would perform AD, 30.3% axillary radiotherapy, and 67.1% no additional axillary treatment, while with macro-metastases, these proportions were 21.3%, 52.2%, and 26.5%, respectively. In cases of mastectomy and of nodal extracapsular extension, 43.4% and 36% of surgeons, respectively, recommended AD. For clinically negative axilla and suspicious findings at ultrasonography, 69% of the surgeons would apply the Z11 approach. Most applied the Z11 criteria in cases of younger patients (83.6%) and triple-negative and/or HER2 positive tumors (74%). AD was significantly more likely to be recommended by surgeons who did not work in academic institutes, who worked in locations other than capital cities, who were not board-certified, and who were ≥ 50 years old.

CONCLUSIONS

This survey revealed substantial changes in axillary surgery management in cN0/pathologically positive SLN, particularly following publication of the updated Z11 results and other similar studies. A better education environment and long-term follow-up were factors associated with the incorporation of Z11-related changes in practice.

A National Survey of Breast Surgeons and Radiation Oncologists on Contemporary Axillary Management in Mastectomy Patients

BACKGROUND

Management of axillary lymph nodes in breast cancer has undergone significant change over the past decade through landmark clinical trials. This study aimed to assess national practice patterns in axillary management in patients undergoing upfront mastectomy and examines what guides provider recommendations.

METHODS

A national case-based survey study was performed of surgeons and radiation oncologists from July to August 2020. Surgeons were identified through the American Society of Breast Surgeons (ASBrS) after review and approval by the ASBrS Research Committee, and radiation oncologists were identified through an institutional database. Both descriptive and comparative statistical analyses were performed.

RESULTS

Overall, 994 providers responded-680 surgeons and 314 radiation oncologists. Surgeons were older and in practice longer (p < 0.05) and treated a higher percentage of breast patients (81% vs. 40%, p < 0.001). Most surgeons were hospital-employed (43%), whereas most radiation oncologists were in private practice (40%; p < 0.001). Fifty-two percent of surgeons routinely send sentinel lymph nodes (SLNs) for frozen section (52%) during mastectomy, of which 78% proceed directly to axillary lymph node dissection (ALND) if positive. There was significant variability in treatment recommendations between the two groups among the hypothetical cases (p < 0.001). In the setting of low disease burden in the SLNs, > 30% of surgeons recommended ALND, while radiation oncologists recommend axillary radiotherapy over axillary clearance (p < 0.001).

CONCLUSION

There is significant heterogeneity in the management of the axilla in mastectomy patients with pathologically positive SLNs, both between and among surgeons and radiation oncologists. Efforts should be made to assist both groups in identifying de-escalation opportunities to ensure that mastectomy patients with positive SLNs are treated appropriately.

Extracapsular extension and tumor implants in lymph nodes with canine mammary carcinoma metastasis: Study of the impact on survival

Regional lymph node status impacts survival in dogs with malignant mammary tumors. However, few studies have evaluated extracapsular extension and tumor implants in regional lymph node metastases in dogs with mammary carcinoma. Therefore, 84 cases of mammary carcinomas with metastases in inguinal and/or axillary lymph nodes from female dogs of different breeds and a total of 139 metastatic lymph nodes were evaluated by routine histological staining. Clinical and pathological characteristics of primary tumors as well as the presence of extracapsular extension and tumor implants in the lymph nodes were analyzed, in addition to survival. One to 5 lymph nodes were evaluated in each case. Extracapsular extension and tumor implants were present in 17.9% and 39.3% of cases, respectively. The simultaneous presence of extracapsular extension and tumor implants were associated with an increased risk of death (hazard ratio 10.46). In addition, "special type carcinomas", high histological grade (grade III), and presence of extracapsular extension associated with tumor implants were related to a worse prognosis and shorter survival times (p < 0.05). Based on these results, we highlight the importance of identifying extracapsular extension and tumor implants in dogs with metastatic mammary carcinomas, as they are associated with a higher risk of death and shorter survival.

Extranodal Tumor Deposits in the Axillary Fat Indicate the Need for Axillary Dissection Among T1-T2cN0 Patients with Positive Sentinel Nodes

BACKGROUND

The American College of Surgeons Oncology Group (ACOSOG) Z0011 trial demonstrated the safety of omitting axillary lymph node dissection (ALND) in T1-T2cN0 patients with fewer than three positive sentinel nodes (SLNs) undergoing breast-conservation therapy. While microscopic extracapsular extension (mECE) > 2 mm is associated with increased nodal burden, the significance of extranodal tumor deposits (ETDs) in the axillary fat is uncertain.

METHODS

Consecutive patients with T1-T2cN0 breast cancer undergoing sentinel node biopsy and ALND for SLN metastases from January 2010 to December 2018 were identified. ETDs were defined as intravascular tumor emboli or metastatic deposits in the axillary fat. Clinicopathologic characteristics and nodal burden were compared by ETD status.

RESULTS

Among 1114 patients, 113 (10%) had ETDs: 81 (72%) were intravascular tumor emboli and 32 (28%) were soft tissue deposits. Patients with ETDs had larger tumors (median 2.2 vs. 2.1 cm; p = 0.033) and more often had mECE (83% vs. 44%; p < 0.001). On univariable analysis, presence of ETDs (odds ratio [OR] 9.66, 95% confidence interval [CI] 6.36-14.68), larger tumors (OR 1.47, 95% CI 1.25-1.72), and mECE (OR 10.73, 95% CI 6.86-16.78) were associated with four or more additional positive non-SLNs (NSLNs; all p < 0.001). On multivariable analysis, ETDs remained associated with four or more positive NSLNs (OR 5.67, 95% CI 3.53-9.08; p < 0.001). ETDs were strongly associated with four or more positive NSLNs (OR 7.15, 95% CI 4.04-12.67) among patients with one to two positive SLNs (n = 925).

CONCLUSIONS

Among T1-T2cN0 patients with SLN metastases, ETDs are strongly associated with four or more positive NSLNs at ALND. Even among those who may otherwise meet the criteria for omission of ALND, the presence of ETDs in axillary fat warrants consideration of ALND.