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.

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.

Clinical relevance of a degree of extracapsular extension in a sentinel lymph node in breast cancer patients: a single-centre study

In some breast cancer (BC) patients, an examination of lymph nodes dissected during sentinel lymph node biopsy (SLNB) demonstrates a presence of metastatic lesions and extracapsular extension (ECE) in a SLN. This study aimed to evaluate clinical relevance of ECE in BC patients. This is a retrospective analysis of 891 patients with cancer metastases to SLN, referred to supplementary axillary lymph node dissection (ALND), hospitalized between Jan 2007 and Dec 2017. Clinical and epidemiological data was evaluated. Long-term treatment outcomes were analysed. In 433 (48.6%) patients, cancer metastases were limited to the SLN (group I), in 61 (6.8%) patients the SLN capsule was exceeded focally (≤ 1 mm—group II). In 397 (44.6%) patients, a more extensive ECE was found (> 1 mm—group III). Metastases to non-sentinel lymph nodes (nSLNs) were diagnosed in 27.0% patients from group I, 44.3% patients from group II and in 49.6% patients from group III. No statistically significant differences were observed in long-term treatment outcomes for compared groups. The presence of ECE is accompanied by a higher stage of metastatic lesions in the lymphatic system. The differences in this respect were statistically significant, when compared to the group of ECE(−) patients. ECE, regardless of its extent, did not impact the long-term treatment results. ECE remains an indication for supplementary ALND and for other equivalent cancer treatment procedures, regardless of ECE size.

Efficacy of chemotherapy for lymph node-positive luminal A subtype breast cancer patients: an updated meta-analysis

Objective

To assess the association between chemotherapy and prognosis of patients with breast cancer of luminal A subtype and lymph node-positive, luminal A subtype breast cancer

Methods

Articles published between January 1, 2010, and May 1, 2020, were collected from PubMed, Embase, and Web of Science databases. On the basis of a test for heterogeneity, we selected the random effects model or fixed effects model for meta-analysis. Article quality was evaluated by sensitivity analysis, and Begg’s and Egger’s tests were used to measure publication bias.

Results

Six eligible articles were identified. The hazard ratio of overall survival of luminal A breast cancer patients who received both chemotherapy and endocrine therapy was 1.73 (95% CI 1.23, 2.43). The hazard ratio of overall survival for lymph node-positive, luminal A breast cancer patients who received chemotherapy and endocrine therapy was 1.86 and 95% CI 1.26, 2.81. The hazard ratio of relapse-free survival to disease-free survival was 1.30 (95% CI 0.85, 1.77). Tumor size, vascular invasion, and age did not show significant correlations with breast cancer prognosis.

Conclusion

Compared with endocrine therapy alone, the addition of chemotherapy did not improve the prognosis of patients with luminal type A and lymph node positive cancer; instead, side effects of the additional chemotherapy may have negatively affected prognosis. Prospective studies are needed to determine whether the number of positive lymph nodes also correlates with efficacy of chemotherapy of luminal type A breast cancer.

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.

A nomogram to predict non-sentinel lymph node metastasis in patients with initial cN+ breast cancer that downstages to cN0 after neoadjuvant chemotherapy

BACKGROUND AND OBJECTIVES

This study mainly explored the factors that influence non-sentinel lymph node (NSLN) metastasis in patients with breast cancer (BC) whose axillary lymph nodal status changed from clinically node positive (cN+) to clinically node negative (cN0) after neoadjuvant chemotherapy (NAC).

METHODS

We retrospectively analyzed the clinicopathological factors affecting NSLN metastasis in a total of 179 patients with cN+ BC downstaged to cN0 (120 in the training set and 59 in the validation set) who underwent both sentinel lymph node (SLN) biopsy and axillary lymph node dissection following NAC.

RESULTS

Among 179 patients enrolled, the overall NSLN metastatic rate was 24.0% (95% confidence interval [CI]: 17.7%-30.3%). In multivariate logistic regression analysis, the number of positive SLNs achieving a pathological complete remission of the breast and clinical node staging was independent predictors of NSLN metastasis. A nomogram was established based on these factors and displayed a good discriminatory capability, with an area under the curve of 0.919 (95% CI: 0.865-0.973) for the training set and 0.900 (95% CI: 0.812-0.988) for the validation set and its clinical utility was confirmed by the decision curve analysis.

CONCLUSIONS

The nomogram established showed the ability to predict NSLN metastases in patients with initial cN+ BC that downstaged to cN0 after NAC.

The Prognostic Impact of Extracapsular Lymph Node Involvement in Esophageal Squamous Cell Carcinoma

BACKGROUND

The role of extracapsular lymph node involvement (ELNI) in esophageal cancer has not been fully investigated. We aim to assess its incidence and prognostic significance in patients with esophageal squamous cell carcinoma (ESCC) treated with and without neoadjuvant treatments.

METHODS

Data of patients who underwent esophagectomy for ESCC in a single medical center was retrospectively reviewed. Patients with positive lymph node involvement were classified as either with ELNI or without ELNI (intracapsular lymph node involvement, ILNI). The impact of ELNI on overall survival (OS), disease-free survival (DFS), and disease recurrence was analyzed.

RESULTS

A total of 336 patients, including 179 without (NCRT -) and 157 with (NCRT +) neoadjuvant chemoradiotherapy, were included. Seventy-two of 179 (40.2%) patients in NCRT - group were with positive lymph node, of whom 19 (26.4%) had ELNI, whereas 49 (31.2%) patients in NCRT + group had positive lymph node, of whom 25 (51.0%) had ELNI. In NCRT + group, patients with ELNI had worse outcome compared to those with ILNI in 5-year OS (10.4 vs. 13.8%, p = 0.008), and DFS (5.3 vs. 17.5%, p = 0.008). The presence of ELNI was also associated with more distant recurrence (p = 0.03). In contrast, there was no survival difference between patients with ELNI and ILNI in NCRT - group.

CONCLUSIONS

Compared with ILNI, ELNI is a significant poor prognostic factor in patients with ESCC treated with neoadjuvant treatments, but not in those with primary surgery.

The Basics of Sentinel Lymph Node Biopsy: Anatomical and Pathophysiological Considerations and Clinical Aspects

Sentinel lymph node (SLN) is the first node to receive the drainage directly from a tumor. Detection and pathological examination of the SLN is an important oncological procedure that minimizes morbidity related to extensive nodal dissection. SLN biopsy was first reported in 1960 but took approximately 40 years to come into general practice following reports of good outcomes in patients with melanoma. After many years of observation and research on its use in various malignancies SLN biopsy has become the standard surgical treatment in patients with malignant melanoma, breast, vulvar, and cervical cancers. Along with the introduction of new technologies, such as the fluorescent dyes indocyanine green (ICG) and near-infrared fluorescence (NIR), and pathologic ultrastaging, SLN detection rate has increased and false-negative rate has decreased. This literature review aimed to present an overview of the basic concepts and clinical aspects of SLN biopsy in the light of the current research.

Primary Penile Cancer: The Role of Adjuvant Radiation Therapy in the Management of Extranodal Extension in Lymph Nodes

BACKGROUND

In head and neck cancer, the presence of extranodal extension (ENE) in lymph nodes (LNs) has been shown prospectively to require adding chemotherapy to postoperative radiation therapy (RT). Limited data exist regarding ENE in LNs from primary penile cancer (PeCa).

OBJECTIVE

To determine the association of RT and ENE in PeCa.

DESIGN, SETTING, AND PARTICIPANTS

We retrospectively analyzed the outcomes of 93 patients with pT1-4 N3 M0 (American Joint Committee on Cancer 7th edition) squamous cell carcinoma of the penis across four international centers.

INTERVENTION

If the inguinal nodal specimen had ENE or two or more positive inguinal LNs, RT was delivered to an ipsilateral inguinal field. An ipsilateral pelvic field was added for positive pelvic LNs on dissection. The delivered dose was usually 50Gy in 25 daily fractions.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Clinical and demographic characteristics of relapse-free (RFS), disease-specific (DSS), and overall (OS) survival were compared by ENE status and receipt of adjuvant RT.

RESULTS AND LIMITATIONS

Seventy-two percent of patients had inguinal ENE, and 49% had pelvic ENE. On multivariable analysis (MVA) of ENE-negative patients, an OS benefit was noted with postoperative chemotherapy (p=0.038) and inguinopelvic RT (p=0.037). RFS suffered with worsening grade of the lesion (moderately: p=0.027; poorly: p=0.038), but was improved with groin (p=0.016) and inguinopelvic (p=0.006) RT. On MVA of patients with ENE, inguinopelvic RT was associated with better DSS (p=0.041). Grade impacted DSS (moderately: p=0.043; poorly: p=0.033), and poorly differentiated lesions impacted RFS (p=0.013).

CONCLUSIONS

Inguinopelvic RT may benefit regional control in PeCa patients with positive pelvic LNs, but this appears to be limited to those without ENE.

PATIENT SUMMARY

For patients with penile cancer and positive pelvic lymph nodes, postoperative radiation therapy was found to decrease the likelihood of disease recurrence in the groin or pelvis only if extranodal extension was absent.

Analysis of factors related to non-sentinel lymph node metastasis in 296 sentinel lymph node-positive Chinese breast cancer patients

Objective:

Axillary lymph node dissection (ALND) may be unnecessary in 20%–60% of breast cancer patients with sentinel lymph node (NSLN) metastasis. The aim of the present study was to review the medical records of Chinese patients with early-stage breast cancer and positive NSLN metastasis to identify clinicopathological characteristics as risk factors for non-NSLN metastasis.

Methods:

The medical records of 2008 early-stage breast cancer patients who received intraoperative sentinel lymph node biopsy (SLNB) between 2006 and 2016 were retrospectively reviewed. These patients were clinically and radiologically lymph node-negative and had no prior history of receiving neoadjuvant chemotherapy or endocrinotherapy. The clinicopathological characteristics of patients with positive NSLN metastasis who underwent ALND were investigated.

Results:

In the present study, 296 patients with positive NSLN metastases underwent ALND. Positive non-NSLN metastases were confirmed in 95 patients (32.1%). On univariate analysis, ≥ 3 positive NSLN metastases (P <0.01), NSLN macrometastases ( P = 0.023), and lymphovascular invasion (P = 0.04) were associated with non-NSLN metastasis (P <0.05). In multivariate analysis, the number of positive SLNs was the most significant predictor of non-SLN metastasis. For patients with 0, 1, 2, or 3 associated risk factors, the non-SLN metastatic rates were 11.5%, 22.5%, 35.2%, and 73.1%, respectively.

Conclusions:

The number of positive NSLNs, NSLN macrometastases, and lymphovascular invasion were correlated with non-SLN metastasis. The number of positive SLNs was an independent predictor for non-NSLN metastasis. When 2 or 3 risk factors were present in one patient, the probability of non-NSLN was higher than that in the American College of Surgeons Oncology Group Z0011 trial (27.3%); thus, avoiding ALND should be considered carefully.

Is extracapsular nodal extension in sentinel nodes a predictor for nonsentinel metastasis and is there an impact on survival parameters?-A retrospective single center cohort study with 324 patients

The Z0011 trial has fundamentally changed axillary management in breast cancer patients. However, some important questions remain, like the role of extracapsular nodal extension (ENE) in positive sentinel nodes and the need for further axillary treatment. In this retrospective cohort study, we reviewed and analyzed data from 342 clinically node negative (cN0) breast cancer patients with a positive sentinel node and subsequent axillary lymph node dissection (ALND) from the BRENDA data base. The 104 (30.4%) ENE positive patients had a significantly higher proportion of ≥3 positive axillary lymph nodes (65.0%) compared to ENE negative patients with a positive sentinel node (21.4%). Likewise, ENE positive patients had significantly more often lymph node metastasis size >2 mm (96.2%) than ENE negative patients (72.7%). T1 status was observed significantly more often in ENE negative patients (53.2%) than in ENE positive patients (24.0%). While ENE was linked to worse overall survival in univariate analysis, this effect disappeared when adjusting for nodal status, age, and comorbidities in multivariate analysis. ENE of the sentinel node is an important predictor for nonsentinel lymph node involvement. We suggest that ENE influences survival only via a higher number of positive nodes - one of the most predictive parameters for survival outcome in breast cancer.

Comparison of CK-IHC assay on serial frozen sections, the OSNA assay, and in combination for intraoperative evaluation of SLN metastases in breast cancer

BACKGROUND

Intraoperative evaluations of sentinel lymph node (SLN) metastases are performed for providing appropriate and immediate axillary treatments in breast cancer patients who do not meet Z0011 criteria; however, standard intraoperative procedure has not yet been established.

METHODS

We consecutively performed intraoperative evaluation for SLN metastases using both a cytokeratin immunohistochemistry (CK-IHC) assay on serial frozen sections and a one-step nucleic acid amplification (OSNA) assay of the remaining whole node in patients with invasive breast cancer. In this article, we compared the intraoperative diagnostic ability of CK-IHC assay, the OSNA assay, and in combination.

RESULTS

Between August 2009 and May 2017, 1,103 SLNs from 499 consecutive clinically node-negative invasive breast cancers were intraoperatively evaluated for SLN metastases using an OSNA and CK-IHC assay. The detection rates of SLN metastases by the OSNA and CK-IHC assays and in combination were 11.8, 12.1, and 14.5%, respectively. The concordance rate between the intraoperative SLN findings of the OSNA and CK-IHC assays was 94.9% (95% confidence interval 93.6-96.2%). The false negative rate for the OSNA assay was 3.1% (30/973), including 3 (0.3%) macrometastases and 27 (2.8%) micrometastases, and for the CK-IHC assay was 2.7% (26/969), including 1 (0.1%) OSNA ++ and 25 (2.6%) OSNA +.

CONCLUSIONS

The CK-IHC assay and the OSNA assay have compatible diagnostic abilities in intraoperative evaluations for SLN metastases. The low incidence of false negative results with limited disease burden suggests that both assays can be reliable techniques for intraoperative diagnoses of SLN metastases in breast cancer patients.

Sentinel Lymph Nodes for Breast Carcinoma: A Paradigm Shift

CONTEXT

-Sentinel lymph node biopsy has been established as the new standard of care for axillary staging in most patients with invasive breast carcinoma. Historically, all patients with a positive sentinel lymph node biopsy result underwent axillary lymph node dissection. Recent trials show that axillary lymph node dissection can be safely omitted in women with clinically node negative, T1 or T2 invasive breast cancer treated with breast-conserving surgery and whole-breast radiotherapy. This change in practice also has implications on the pathologic examination and reporting of sentinel lymph nodes.

OBJECTIVE

-To review recent clinical and pathologic studies of sentinel lymph nodes and explore how these findings influence the pathologic evaluation of sentinel lymph nodes.

DATA SOURCES

-Sources were published articles from peer-reviewed journals in PubMed (US National Library of Medicine) and published guidelines from the American Joint Committee on Cancer, the Union for International Cancer Control, the American Society of Clinical Oncology, and the National Comprehensive Cancer Network.

CONCLUSIONS

-The main goal of sentinel lymph node examination should be to detect all macrometastases (>2 mm). Grossly sectioning sentinel lymph nodes at 2-mm intervals and evaluation of one hematoxylin-eosin-stained section from each block is the preferred method of pathologic evaluation. Axillary lymph node dissection can be safely omitted in clinically node-negative patients with negative sentinel lymph nodes, as well as in a selected group of patients with limited sentinel lymph node involvement. The pathologic features of the primary carcinoma and its sentinel lymph node metastases contribute to estimate the extent of non-sentinel lymph node involvement. This information is important to decide on further axillary treatment.

Prediction of nonsentinel lymph node metastasis in breast cancer patients with one or two positive sentinel lymph nodes

OBJECTIVE

The aim of the present study was to investigate the association between non sentinel lymph node metastasis (NSLNM) and clinicopathological factors, particularly in the case of sentinel lymph node (SLN) metastasis in one or two, in clinically node negative patients with breast cancer.

METHODS

Between 10/2010 and 10/2014, 350 sentinel lymph node biopsy (SLNB) were performed in patients with histologically proven primary breast cancer in our clinic. The data collection includes the following characteristics: age, pathological tumor size, histological type, histological grade, lymphovascular invasion (LVI), number of positive SLN, size of the SLN metastasis (macrometastasis, micrometastasis, isolated tumor cells), multifocality (MF), extracapsuler invasion (ECI) of the SLN, the estrogen receptor (ER) status, the progesterone receptor (PR) status and the Her 2 receptor status, Ki 67 reseptor status. Data were collected retrospectively and then analyzed.

RESULTS

A successful SLN biopsy were performed in 345 (98.5%) cases. SLN metastases were detected in 110 (31.8%) cases. These patients then underwent axillary dissection; among these patients, 101 (91.8%) had only one to two positive SLNs. Of the 101 patients with positive SLN biopsies, 32 (31.6%) had metastases in the NSLNs. Univariate and multivariate analysis showed that lymphovascular invasion, extracapsular invasion (ECI), Her-2 receptor positive, and Ki-67 > 14% were related to NSLNM (p<.0.05).

CONCLUSION

The predicting factors of NSLNM were LVI, ECI, Ki-67 level, Her-2 reseptor positive and but should be further validated in our institutions, different institutions and different patient groups prospectively.

Clinicopathologic Significance of Extranodal Tumor Extension in Colorectal Adenocarcinoma with Regional Lymph Node Metastasis

Background. This study investigated the clinicopathologic significance of extranodal tumor extension in colorectal adenocarcinoma with lymph node metastasis. Method. Included were 419 patients who underwent curative resection for primary colorectal adenocarcinoma. Results. Extranodal tumor extension was observed more frequently in tumors with ulceroinfiltrative gross type (p = 0.026), higher histologic grade (p = 0.012), high grade tumor budding (p = 0.003), vascular invasion (p < 0.001), perineural invasion (p = 0.015), tumor deposit (p < 0.001), high ratio of metastatic/total lymph nodes (p < 0.001), and high pN stage (p < 0.001). Overall survival was significantly different between an extranodal tumor extension (−) group and an extranodal tumor extension (+) group for both N1 (p = 0.022) and N2 homogeneous staging (p = 0.007). Both overall (p = 0.002) and disease-free survival (p = 0.001) were significantly different between the two groups in an N1a homogeneous group and overall survival was significantly different (p = 0.016) in an N2b homogeneous group. Conclusion. Our study demonstrated that extranodal tumor extension was a useful prognostic factor for colorectal adenocarcinoma with lymph node metastasis, especially in homogeneous pN staging groups.

Extra-nodal extension of sentinel lymph node metastasis is a marker of poor prognosis in breast cancer patients: A systematic review and an exploratory meta-analysis

Invasive breast cancer is the most common malignancy in women. Its most common site of metastasis is represented by the lymph nodes of axilla, and the sentinel lymph node (SLN) is the first station of nodal metastasis. Axillary SLN biopsy accurately predicts axillary lymph node status and has been accepted as standard of care for nodal staging in breast cancer. To date, the morphologic aspects of SLN metastasis have not been considered by the oncologic staging system. Extranodal extension (ENE) of nodal metastasis, defined as extension of neoplastic cells through the nodal capsule into the peri-nodal adipose tissue, has recently emerged as an important prognostic factor in several types of malignancies. It has also been considered as a possible predictor of non-sentinel node tumor burden in SLN-positive breast cancer patients. We sought out to clarify the prognostic role of ENE in SLN-positive breast cancer patients in terms of overall and disease-free survival by conducting a systematic review and meta-analysis. Among 172 screened articles, 5 were eligible for the meta-analysis; they globally include 624 patients (163 ENE+ and 461 ENE-) with a median follow-up of 58 months. ENE was associated with a higher risk of both mortality (RR = 2.51; 95% CI: 1.66-3.79, p < 0.0001, I(2) = 0%) and recurrence of disease (RR = 2.07, 95% CI: 1.38-3.10, p < 0.0001, I(2) = 0%). These findings recommend the consideration of ENE from the gross sampling to the histopathological evaluation, in perspectives to be validated and included in the oncologic staging.