Biological Significance of Occult Micrometastases in Histologically Negative Axillary Lymph Nodes in Breast Cancer Patients Using the Recent American Joint Committee on Cancer Breast Cancer Staging System

Cross-attention multi-branch CNN using DCE-MRI to classify breast cancer molecular subtypes

Purpose

The aim of this study is to improve the accuracy of classifying luminal or non-luminal subtypes of breast cancer by using computer algorithms based on DCE-MRI, and to validate the diagnostic efficacy of the model by considering the patient's age of menarche and nodule size.

Methods

DCE-MRI images of patients with non-specific invasive breast cancer admitted to the Second Affiliated Hospital of Dalian Medical University were collected. There were 160 cases in total, with 84 cases of luminal type (luminal A and luminal B and 76 cases of non-luminal type (HER 2 overexpressing and triple negative). Patients were grouped according to thresholds of nodule sizes of 20 mm and age at menarche of 14 years. A cross-attention multi-branch net CAMBNET) was proposed based on the dataset to predict the molecular subtypes of breast cancer. Diagnostic performance was assessed by accuracy, sensitivity, specificity, F1 and area under the ROC curve (AUC). And the model is visualized with Grad-CAM.

Results

Several classical deep learning models were included for diagnostic performance comparison. Using 5-fold cross-validation on the test dataset, all the results of CAMBNET are significantly higher than the compared deep learning models. The average prediction recall, accuracy, precision, and AUC for luminal and non-luminal types of the dataset were 89.11%, 88.44%, 88.52%, and 96.10%, respectively. For patients with tumor size <20 mm, the CAMBNET had AUC of 83.45% and ACC of 90.29% for detecting triple-negative breast cancer. When classifying luminal from non-luminal subtypes for patients with age at menarche years, our CAMBNET model achieved an ACC of 92.37%, precision of 92.42%, recall of 93.33%, F1of 92.33%, and AUC of 99.95%.

Conclusions

The CAMBNET can be applied in molecular subtype classification of breasts. For patients with menarche at 14 years old, our model can yield more accurate results when classifying luminal and non-luminal subtypes. For patients with tumor sizes ≤20 mm, our model can yield more accurate result in detecting triple-negative breast cancer to improve patient prognosis and survival.

Prognostic significance of occult lymph node metastases in breast cancer: a meta-analysis

Background

Occult metastases in axillary lymph nodes have been reported to be associated with poor prognosis in patients with breast cancer. However, studies on the prognostic value of occult metastases have shown controversial results. This meta-analysis aimed to evaluate the prognostic significance of occult lymph node metastases in breast cancer.

Methods

Studies published until May, 2020, which retrospectively examined negative lymph nodes by stepsectioning and/or immunohistochemistry, were retrieved from MEDLINE, EMBASE, CNKI, and Cochrane Library databases. The pooled Relative Risk (RR) with 95% confidence interval (95% CI) for overall survival (OS) and disease-free survival (DFS) were calculated to examine the associations between occult metastases and prognosis.

Results

Patients with occult metastases in axillary lymph nodes had poorer five-year DFS (RR = 0.930; 95% CI = 0.907–0.954) and OS (RR = 0.972; 95% CI = 0.954–0.990). Furthermore, the DFS (RR = 0.887; 95% CI = 0.810–0.972) and OS (RR = 0.896; 95% CI = 0.856–0.939) of patients with occult metastases were significantly lower after a ten-year follow-up.

Conclusions

Occult metastases in the axillary lymph nodes are associated with poorer DFS andOS of patients with breast cancer. Occult metastases might serve as a predictive factor of survival outcomes in patients with breast cancer.

Adjuvant chemotherapy for breast cancer patients with axillary lymph node micrometastases

BACKGROUND

The axillary lymph node status is one of the most important prognostic factors in patients with early breast cancer. However, the impact of axillary lymph node micrometastases on survival remains unclear. There are no consistent recommendations for adjuvant chemotherapy (CHT). In this context, we aimed to investigate the impact of micrometastases on the clinical outcome of breast cancer patients according to the adjuvant CHT performed.

PATIENTS AND METHODS

We conducted a retrospective population-based registry study of 26,465 patients aged between 24 and 97 years with primary breast cancer diagnosed between 2003 and 2017. Of these patients, 8856 with early breast cancer were eligible for analysis: 8316 (93.9%) were node negative and 540 (6.1%) had lymph node micrometastases.

RESULTS

The median follow-up was 7.2 years, with a confidence interval (CI) of 7.1-7.3 years. Patients with lymph node micrometastases (pN1mi) without adjuvant CHT have reduced 10-year overall survival (OS) and recurrence-free survival (RFS) compared to patients who had axillary lymph node micrometastases and received an adjuvant CHT. However, this effect disappeared after adjustment for age, tumor size and tumor grading. Furthermore, in the group of patients with lymph node micrometastases, the administration of adjuvant CHT did not improve OS or RFS, compared to patients with lymph node micrometastases without adjuvant CHT: hazard ratio for treated patients was 1.51 (95% CI 0.80-2.85, p = 0.208) for OS and 1.12 (95% CI 0.63-1.97, p = 0.705) for RFS.

CONCLUSION

Patients with axillary lymph node micrometastases showed a comparable outcome to node negative patients and their outcome was not significantly improved with CHT. Thus, axillary lymph node micrometastases should not be considered in the treatment decision.

One Step Nucleic Acid Amplification (OSNA) positive micrometastases and additional histopathological NSLN metastases: Results from a single institution over 53 months

INTRODUCTION

The role of sentinel lymph node micrometastases on histopathological analysis is controversial in axillary staging and management in clinically node negative breast cancer. Long-term studies addressing the clinical relevance of occult breast cancer in sentinel lymph nodes based on molecular analysis are lacking. One Step Nucleic Acid Amplification (OSNA), a highly sensitive assay of cytokeratin 19 mRNA, is used intra-operatively for the detection of lymph node macro- and micrometastases in breast cancer.

AIM

The aim of this study is to review the rate of micrometastases and further histopathological NSLN metastases, in our unit following the introduction of OSNA in Guildford.

METHODS

Data was collected prospectively from the period of introduction 01/12/2008 to 31/05/2013. All patients eligible for sentinel lymph node biopsy were offered OSNA and operations were performed by the consultant breast surgeons. Presence or absence of micro-metastases depends on the agreed cut-off point on the amplification curve. On detection of micrometastases (+) and positive but inhibited (i+) metastases, a level 1 axillary clearance (ANC) was performed and for a macrometastasis (++), a level 3 ANC was carried out.

RESULTS

66% of the patients had negative SLN (n = 672) and 34% (n = 336) had positive sentinel lymph nodes who had further axillary surgery. Of these, 45% (n = 152/336) had macrometastases, 40% (n = 136/336) had micrometastases and 15% (48/336) had positive but inhibited results. There was no difference in the patient demographics and tumour characteristics in the various positive SLN groups. In patients with micrometastases, 15% (20/136) had further positive NLSNs and a further 6% (8/136) had >4 overall positive nodes (SLN + NSLN) thus requiring adjuvant supraclavicular/chest wall radiotherapy (p < 0.05). 25% of node positive patients had further NLSN metastases (85/336) and in these patients, the ratio of positive SLN/harvested SLN (+SLN/SLN) is constant at 1:1. This shows the likelihood of further positive NSLNs if all the harvested lymph nodes are positive. This linear trend is present in both micro-and macrometastases, thus correlating with the size and number of NSLN metastases.

CONCLUSION

Our study reflects the tumour burden of NSLNs based on the molecular analysis of the SLN. OSNA has the potential to accurately identify axillary micrometastases. Micro-metastases are important as some of the patients with micrometastases had overall four positive nodes [SLN + NSLN] (criteria for radiotherapy in the absence of other adverse clinicopathological features). Also, our study highlights certain factors that predict the NSLN metastases, pending validation by further prospective long-term data. This will allow accurate calculation of the axillary tumour burden, particularly in patients with micro-metastases.

Germline CDKN2A mutations in Brazilian patients of hereditary cutaneous melanoma

Approximately 10 % of all cutaneous melanoma cases occur in a familial context. The major susceptibility gene for familial melanoma is CDKN2A. In Latin America, genetic studies investigating melanoma predisposition are scarce. The aim of this work was to investigate germline CDKN2A point mutations and genomic rearrangements in a cohort of 59 Brazilian melanoma-prone patients. Screening of CDKN2A alterations was performed by sequencing and multiplex ligation probe amplification. Germline CDKN2A mutations affecting p16(INK4a) were detected in 8 unrelated probands (13.6 %), including 7 familial cases and one patient with multiple melanomas; 4 out of 8 mutation carriers met the criteria for familial melanoma and had multiple primary lesions. Although this study adds to the literature on melanoma susceptibility in Latin America, it is limited by the small size of the cohort. Our findings suggest that stringent inclusion criteria led to a substantially increased rate of CDKN2A mutation detection. This consideration should be taken into account when referring patients for genetic screening in a setting of limited budget, such as in developing countries.

Clinical significance and management of sentinel node micrometastasis in invasive breast cancer

Axillary node status is one of the most important prognostic indicators in patients with invasive breast cancer. Sentinel node biopsy allows an exhaustive examination of the lymph node and has led to an increased detection rate of small tumor deposits. Patients with micrometastatic deposits can have nonsentinel node involvement, including macrometastatic deposits. Sentinel node micrometastases are associated with an adverse impact on disease recurrence and survival. Axillary dissection does not offer an advantage in reducing the incidence of disease recurrence or survival. However, the long-term outcomes can be improved with the use of adjuvant chemotherapy, and it would be reasonable to consider systemic treatment in these patients.

Potential applications of quantum dots in mapping sentinel lymph node and detection of micrometastases in breast carcinoma

Breast cancer cure aims at complete elimination of malignant cells and essentially requires detection and treatment of any micrometastases. Here, we present a review of the current methods in use and the potential role of the quantum dots (QDs) in detection and visualization of sentinel lymph node and micrometastases in breast cancer patients. The traditional histopathological, immunohistochemical, and reverse transcriptase polymerase chain reaction procedures being used for micrometastases detection had serious drawbacks of high false negativity, specificity variations and false positivity of the results. Photon emission fluorescence multiplexing characteristics of the quantum dots make them potentially ideal probes for studying the dynamics of cellular processes over time such as continuous tracking of cell migration, differentiation, and metastases. In breast cancer, QDs based molecular and genomic detections had an unparallel high sensitivity and specificity.

Sentinel lymph node biopsy in early-stage breast cancer patients: improved survival through better staging?

PURPOSE

The objective of this review is to summarize the evidence demonstrating that the sentinel lymph node (SLN) procedure is not only associated with significantly less morbidity compared to the axillary dissection, but may also result in better staging and improved patient outcomes.

METHODS

A search of MedLine and PubMed articles using the terms "sentinel lymph node biopsy", "breast cancer", "staging", "morbidity", "survival", and "outcomes" was conducted.

RESULTS

Breast cancer staging includes axillary evaluation as an integral component. Over the past two decades, sentinel lymph node biopsy has evolved as a technique that has an improved morbidity over traditional axillary dissection. The sentinel node(s) undergo a more intensive pathologic examination than traditional axillary contents. In the node-negative group of patients, this may have led to stage migration and potentially improved disease-free and overall survival.

CONCLUSION

The SLN procedure is not only associated with significantly less morbidity compared to the axillary lymph node dissection, it may also result in more accurate staging, better axillary tumor control and improved survival.

Assessment of the Memorial Sloan-Kettering Cancer Center nomogram to predict sentinel lymph node metastases in a Dutch breast cancer population

AIM

Sentinel lymph node (SLN) biopsy is an accepted alternative to axillary lymph node dissection to assess the axillary tumour status in breast cancer patients. Memorial Sloan-Kettering Cancer Center (MSKCC) developed a nomogram to predict the likelihood of SLN metastases in breast cancer patients. Nomogram performance was tested on a Dutch population.

METHODS

Data of 770 breast cancer patients who underwent successful SLN biopsy were collected. SLN metastases were present in 222 patients. A receiver operating characteristic (ROC) curve was drawn and the area under the curve was calculated to assess the discriminative ability of the MSKCC nomogram. A calibration plot was drawn to compare actual versus nomogram-predicted probabilities.

RESULTS

The area under the ROC curve for the predictive nomogram was 0.67 (95% confidence interval 0.63-0.72) as compared to 0.75 in the original population. The nomogram was well-calibrated in the Dutch population.

CONCLUSIONS

In a Dutch population, the MSKCC nomogram estimated risk of sentinel node metastases in breast cancer patients well (i.e. calibration) with reasonable discrimination (area under ROC curve). Nomogram performance on core needle biopsy data has to be evaluated prospectively.

Occult axillary lymph node metastases do not have prognostic significance in early stage breast cancer

BACKGROUND

Axillary lymph node status is one of the most powerful prognostic indicators in patients with breast cancer and has implications for adjuvant treatment. It has been demonstrated that enhanced histologic evaluation of axillary lymph nodes, including serial sectioning of paraffin tissue blocks and immunohistochemical (IHC) staining, increases the rate of detection of occult metastases. The clinical significance of occult lymph node metastases has been the subject of debate.

METHODS

In the current study, the authors identified 267 patients who underwent axillary lymph node dissection (ALND) between 1987 and 1995 and were lymph node negative according to a routine pathologic evaluation, which included the complete submission of all lymph nodes and an examination of 1 hematoxylin and eosin (H&E)-stained section per paraffin block. Patients did not receive systemic chemotherapy or hormone therapy. All of the dissected lymph nodes from these patients were re-evaluated by intensified pathologic methods (serial sectioning with H&E levels plus IHC). Occult metastases were categorized by detection method and size. The clinical significance of the occult metastases was determined.

RESULTS

Thirty-nine patients (15%) who had lymph node-negative results on routine evaluation of their ALND specimens had occult metastases identified. Eight of these patients (20%) had macrometastases >2.0 mm, 15 (40%) had micrometastases (range, >0.2 mm to ≤2 mm), and 16 (40%) had isolated tumor cells (≤0.2 mm). The presence of occult metastases and the size of metastases did not affect recurrence-free or overall survival.

CONCLUSIONS

The presence of occult metastasis did not have clinical significance in this cohort of patients with early stage breast cancer.

Is there a requirement for axillary lymph node dissection following identification of micro-metastasis or isolated tumour cells at sentinel node biopsy for breast cancer?

INTRODUCTION

Recent decades have seen a significant shift towards conservative management of the axilla. Increasingly, immunohistochemical analysis of sentinel nodes leads to the detection of small tumour deposits, the significance of which remains uncertain. The aims of this study are to examine patients whose sentinel lymph nodes are positive for macro-metastasis, micro-metastasis or isolated tumour cells (ITCs) and to determine the rate of further nodal disease after axillary lymph node dissection (ALND).

METHODS

A retrospective analysis of all patients undergoing a sentinel lymph node biopsy (SLNB) between January 2007 and December 2010 in a tertiary referral breast unit was performed. Patients who underwent an axillary lymph node dissection for macro-metastasis, micro-metastasis or ITCs were identified. Demographics, histological data and the rate of further axillary disease were examined.

RESULTS

In total, 664 breast cancer patients attended the symptomatic breast unit during the study period, 360 of whom underwent a SLNB. Seventy patients had a SLNB positive for macro-metastasis. All of these patients underwent ALND. A positive SLNB with either micro-metastasis or ITCs was identified in 58 patients. Only 41 of the 58 patients went on to have an ALND, due primarily to variations in surgeons' preferences. Nineteen patients with micro-metastasis underwent an ALND. Four patients had further axillary disease (21%). Twenty-two patients had ITCs identified, of whom only one had further disease (4.5%). No statistically significant difference was found between the two groups in terms of tumour size, grade, lymphovascular invasion or oestrogen receptor status.

CONCLUSION

ALND should be considered in patients with micro-metastasis at SLNB. It should rarely be employed in the setting of SLNB positive for ITCs.

Sentinel lymph node micrometastasis in human breast cancer: an update

INTRODUCTION

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

METHODS

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

RESULTS

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

CONCLUSION

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

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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

AIM

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

MATERIAL AND METHOD

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

RESULTS

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

CONCLUSION

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

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Cytokeratin 19-positive circulating tumor cells in early breast cancer prognosis

In spite of the heterogeneity of breast cancer at the molecular level, circulating tumor cells (CTCs) may provide a novel prognostic marker. Approximately 20–40% of early breast cancer patients have detectable CTCs using reverse transcription PCR for CK19. The detection of CTCs before adjuvant chemotherapy or during tamoxifen administration has been demonstrated to be an independent adverse prognostic factor in women with early-stage breast cancer. The prognostic value of CTC detection is of great significance in subgroups of patients with estrogen receptor-negative and human EGF receptor 2-positive tumors. Prospective clinical trials are warranted in order to validate the use of CTCs as predictive and/or prognostic markers and assess their utility in individualizing therapy of patients with early breast cancer.

Technical limits of comparison of step-sectioning,immunohistochemistry and RT-PCR on breast cancer sentinel nodes: a study on methacarn-fixed tissue

The optimal pathological assessment of sentinel nodes (SLNs) in breast cancer is a matter of debate. Currently, multilevel histological evaluation and immunohistochemistry (IHC) are recommended, but alternative RT-PCR procedures have been developed. To assess the reliability of these different procedures, we devised a step-sectioning protocol at 100 micron-intervals of 74 SLNs using methacarn fixation. mRNA was extracted from sections collected from levels 4 to 5. Mammaglobin, CEA and CK19 were used for RT-PCR. mRNA extraction was successful in 69 SLNs. Of these, 7 showed macrometastases (>2mm), 2 showed micrometastases (<2 mm) and 7 showed isolated tumour cells (ITC) by IHC. RT-PCR was positive for the three markers in 6 of 7 macrometastases and in 1 of 2 micrometastases. In the 2 RT-PCR negative cases, metastases were detected only on sections distant from those analysed by RT-PCR. CEA and/or CK19 were positive by RT-PCR in 3 of 7 ITC and in 23 morphologically negative SLNs. In conclusion, the main goal of our study was to show that the use of alternate sections of the same sample for different procedures is the key reason for the discrepancies between molecular and morphological analyses of SLN. We believe that only prospective studies with quantitative mRNA analysis of specific metastatic markers on the whole lymph node can elucidate the utility of molecular assessments of SLN.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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

CONTEXT

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

OBJECTIVE

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

DATA SOURCES

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

CONCLUSION

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

Lobular phenotype related to occult-metastatic spread in axillary sentinel node and/or bone marrow in breast carcinoma

To determine whether any histological trait was associated with regional and/or systemic spread of occult tumour cells (OTCs) in small size invasive breast cancer, we compared tumour characteristics, axillary sentinel lymph node (SN) and bone marrow (BM) status in a series of 287 pT1T2 cases. Surgery was the first step of treatment, associated with SN procedure and with BM aspiration for the detection of OTC. SN was histologically classified as negative, metastatic (>2mm), micro-metastatic (>0.2mm and 2mm) or involved by OTC detected by immunohistochemistry (Ni+, 0.2mm). BM specimens were analysed after immunocytochemistry and classified as negative or positive with atypical cytokeratin-positive OTC. Metastasis and micro-metastasis in the SN were correlated with size, grade and vascular invasion. In contrast, presence of OTC in both SN and BM was independent of these parameters but positively associated with lobular type. This correlation was also observed for BM status, which was similarly independent of the tumour characteristics. No association was found between SN status and BM status. Our data indicate that, in the course of breast cancer, OTC spreading is frequent and could be an early event, related to lobular histological type but independent of classical histoprognostic parameters, and that the loco-regional metastatic spread of OTC is not a prerequisite for systemic involvement.

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

BACKGROUND

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

STUDY DESIGN

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

RESULTS

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

CONCLUSIONS

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

Promoter hypermethylation in sentinel lymph nodes as a marker for breast cancer recurrence

PURPOSE

Promoter methylation of tumor suppressor genes in histologically negative sentinel lymph nodes (HNSN) of early stage breast cancer patients has not been extensively studied. This study evaluates the methylation frequency and pattern in HNSN to determine if detection of hypermethylation of one or more genes is associated with an increased recurrence risk in node negative breast cancer.

EXPERIMENTAL DESIGN

In 1998, a prospective study of patients with early stage breast cancer and HNSN was initiated in order to correlate sentinel node analysis with clinical outcome. Nodal tissue was selected from 120 HNSN patients for methylation analysis in at least one and up to six sentinel nodes using a panel of nine genes. Corresponding primary breast tumors from 79 patients were also evaluated for hypermethylation. Methylation analysis was performed using nested Methylation Sensitive PCR (n-MSP). Logistical regression was used to evaluate the relationship between clinical recurrence and methylation status.

RESULTS

Over a median follow-up of 79 months, 13 of the 120 patients had clinical recurrence. Hypermethylation of genes was frequently observed in HNSN, but there was no correlation of methylation pattern and clinical recurrence. However, increased frequency of gene methylation of the primary tumor correlated with clinical recurrence.

CONCLUSIONS

Although hypermethylation of multiple genes occurs frequently in HNSN of breast cancer patients, it is not associated with breast cancer recurrence in the first 7 years of clinical follow-up.

Micrometastatic spread in breast cancer: detection, molecular characterization and clinical relevance

Immunocytochemical or molecular assays allow the detection of single disseminated tumor cells (DTCs) in the bone marrow (BM) or the peripheral blood in 10% to 60% of breast cancer patients without signs of metastasis. Results from recently reported studies suggest that circulating tumor cell (CTC) levels may serve as a prognostic marker and be used for early assessment of therapeutic response in patients with metastatic breast cancer. In early stage breast cancer, however, the impact of CTCs is less well established than that of DTCs in BM, where several clinical studies demonstrated that such cells are an independent prognostic factor at primary diagnosis. The characterization of DTCs/CTCs has already shed new light on the complex process underlying early tumor cell dissemination and metastatic progression in cancer patients. Characterization of DTCs should help to identify novel targets for biological therapies aimed to prevent metastatic relapse. In addition, understanding tumor 'dormancy' and identifying metastatic stem cells might result in the development of new therapeutic concepts.

Application of immunohistochemistry to breast lesions

CONTEXT

Immunohistochemistry has an expanding role in mammary pathology that has been facilitated by a growing list of available antibodies and a better understanding of biology.

OBJECTIVE

To explore the key role of immunohistochemistry in guiding adjuvant therapy decisions and sentinel node staging in breast cancer, as well as the role of immunohistochemistry as an aid to distinguishing usual ductal hyperplasia from atypical ductal hyperplasia/low-grade carcinoma in situ; subtyping a carcinoma as ductal or lobular, basal or luminal; ruling out microinvasion in extensive intraductal carcinoma; distinguishing invasive carcinoma from mimics; and establishing that a metastatic carcinoma of unknown primary site has originated in the breast.

DATA SOURCES

Current literature is reviewed, including clinical and pathologic journals.

CONCLUSIONS

As new, targeted treatments for breast cancer are developed, pathologists can expect additional immunohistochemistry applications in the future.

Sentinel node biopsy: interpretation and management of patients with immunohistochemistry-positive sentinel nodes and those with micrometastases

The sentinel node procedure is an adequate tool to identify lymph node metastasis in breast cancer. Sentinel nodes are generally examined with greater attention mainly to exclude, as reliably as possible, lymph node metastasis. To achieve this, many protocols are used, resulting in different rates of micrometastasis or isolated tumor cells encountered. Since the prognostic significance of isolated tumor cells or micrometastasis in the sentinel nodes, and the risk of further axillary lymph node involvement in patients with isolated tumor cells, is uncertain and at most limited, these findings may pose difficulties for clinicians in clinical decision making. Protocols that identify lymph node metastasis, from which the clinical relevance is known, are warranted. Unnecessary lymph node dissections should be avoided.

Significance of sentinel lymph node micrometastases in human breast cancer

BACKGROUND

The significance of micrometastatic disease in the sentinel lymph nodes (SLN) of patients with invasive breast cancer has been questioned. The objective of our study was to review the impact of micrometastatic carcinoma detected by SLN biopsy.

STUDY DESIGN

Between January 1997 and May 2004, 2,408 patients with invasive breast cancer and an SLN with micrometastatic (N0[i+], N1mi) or no metastatic (N0[i-]) disease were identified through our breast database. Slide review was performed and reclassified by the 6(th) edition of the American Joint Committee on Cancer Staging Manual. Of these, 27 were excluded from analysis because of evidence of macrometastatic disease on slide review or enrollment in the American College of Surgeons Oncology Group Z10 study.

RESULTS

Of 2,381 patients, 2,108 were N0(i-), 151 were N0(i+), and 122 were N1mi. Overall and disease-free survivals of patients with an N1mi SLN were substantially worse than those in patients with an N0(i-) SLN (p < 0.001 and p=0.006, respectively). Additional positive non-SLNs were identified in 15.5% (15 of 97) of N1mi patients and 9.3% (10 of 107) of N0(i+) patients undergoing completion axillary lymph node dissection. Overall survival of the N0(i+) SLN patients not undergoing axillary dissection was substantially less than those undergoing axillary dissection (p=0.02).

CONCLUSIONS

Detection of micrometastatic carcinoma (N1mi) in the SLNs of invasive breast cancer patients is a major indicator of poorer survival compared with N0(i-) patients. Although survival of patients with an N0(i+) SLN does not statistically differ from that of N0(i-) patients, 9.3% of these patients had additional axillary nodal disease on axillary dissection, and N0(i+) patients had a decreased survival when axillary dissection was omitted.

Current status in human breast cancer micrometastasis

PURPOSE OF REVIEW

Current research and clinical developments on hematogeneous micrometastasis in breast cancer patients are summarized.

RECENT FINDINGS

Distant metastasis is the leading cause of cancer-related death in breast cancer and bone marrow is a common homing organ for blood-borne disseminated tumor cells derived from primary breast carcinomas. Sensitive immunocytochemical or molecular assays now allow the detection of single disseminated tumor cells in bone marrow or the peripheral blood at a frequency of 10 and these cells are detected in 10-60% of breast cancer patients without clinical or even histopathologic signs of metastasis. Recently, evidence has emerged that the detection of disseminated tumor cells and circulating tumor cells may provide important prognostic information, and in particular might help to monitor efficacy of therapy. Moreover, the characterization of disseminated tumor cells/circulating tumor cells has shed new light on the complex process underlying early tumor cell dissemination and metastatic progression in cancer patients.

SUMMARY

Research on disseminated tumor cells/circulating tumor cells will help to identify novel targets for biological therapies aimed at preventing metastatic relapse and to monitor the efficacy of these therapies. In particular, understanding tumor dormancy and identifying metastatic stem cells might result in the development of new concepts for antimetastatic therapies.

Sentinel lymph nodes in early stage cervical cancer

OBJECTIVES

Lymph node status is the most important prognostic factor in cervical cancer. Sentinel lymph node (SLN) procedures have been purported to reduce peri- and postoperative morbidity and operative time.

METHODS

All patients with surgically managed clinical FIGO stage IA/B1 cervical cancer underwent SLN followed by pelvic lymphadenectomy with technetium+/-lymphazurin from April 2004 to April 2006. 0.1-0.2 mci of filtered sulfur colloid technetium was injected submucosally into 4 quadrants of the exocervix. Lymphazurin (4cc) was only used if technetium was unsuccessful in identifying bilateral sentinel lymph nodes. Serial microsections at 5 microm intervals were performed and stained intraoperatively. Complete pelvic node dissections were performed in all patients.

RESULTS

Forty-two patients underwent SLN, prior to full pelvic lymphadenectomy. Thirty-nine patients were included for the purposes of this study. The incidence in detecting at least one sentinel node was 98% per patient, and 85% per side. Identification of bilateral sentinel lymph nodes was successful in 28 cases (72%). The median number of SLN/side was 2. Three patients were found to have metastatic tumor to lymph nodes. No false negatives were identified. No adverse effects were noted.

CONCLUSIONS

SLN biopsy in cervical cancer is feasible to do, with a low false negative rate. We believe SLN should be evaluated per side and not per patient, that a pelvic lymphadenectomy is otherwise required. By following this protocol, the false negative rate can be minimized. The combined reported FN rate in the literature is 1.8%. If our definition is applied, the majority of reported false negative SLN is not actual false negatives.