Sentinel lymphadenectomy in breast cancer: identification of sentinel lymph node and detection of metastases

Network meta-analysis of novel and conventional sentinel lymph node biopsy techniques in breast cancer

Background

The aim of this network meta‐analysis was to compare the performance of blue dye alone or in combination with radioisotope (technetium‐99m, Tc) with three novel techniques for sentinel lymph node detection in breast cancer: indocyanine green fluorescence (ICG), superparamagnetic iron oxide (SPIO) nanoparticles and contrast‐enhanced ultrasound imaging (CEUS).

Methods

PubMed, Embase, the Cochrane Library, China Knowledge Research Integrated Database, ClinicalTrials.gov and OpenGrey databases were searched up to 31 November 2017, without language restriction. Studies that compared the detection performance of at least one of the novel methods (ICG, SPIO and CEUS) with that of traditional methods (blue dye and/or radioisotope) were included in network meta‐analysis.

Results

Thirty‐five studies were included. Pooled risk ratios (RRs) for Tc (1·09, 95 per cent c.i. 1·04 to 1·15), ICG (1·12, 1·07 to 1·16) and SPIO (1·09, 1·01 to 1·18) showed statistically better performance in detecting sentinel lymph nodes than blue dye alone. ICG had the lowest false‐negative rate, with a RR of 0·29 (0·16 to 0·54), followed by Tc (RR 0·44, 0·20 to 0·96) and SPIO (RR 0·45, 0·14 to 1·45), with blue dye alone as the reference group.

Conclusion

SPIO or ICG alone are superior to blue dye alone and comparable to the standard dual‐modality technique of blue dye with Tc.

Sentinel Lymph Node Evaluation: What the Radiologist Needs to Know

Axillary lymph node status is the single most important prognostic indicator in patients with breast cancer. Axillary lymph node dissection, the traditional method of staging breast cancer, is associated with significant morbidity. Sentinel lymph node biopsy has become standard in patients being treated for breast cancer with clinically negative lymph nodes. There is considerable variation in the medical literature regarding technical approaches to sentinel lymph node biopsy in patients with breast cancer. The purpose of this article is to describe our preferred approaches to sentinel lymph node biopsy with a review of the literature.

Histological examination of sentinel lymph nodes: significance of macrometastasis, micrometastasis, and isolated tumor cells

Sentinel lymph node biopsy has been started in 1990s and has become one of the standard diagnostic procedures used to treat patients with early breast cancer in this century. In Japan, for the microscopic diagnosis of metastasis to sentinel lymph nodes, intraoperative frozen section diagnosis is widely used in combination with subsequent permanent section diagnosis of the residual specimens. Metastatic foci to sentinel lymph nodes have been classified into macrometastasis, micrometastasis, and isolated tumor cells in 2002, and the definition of isolated tumor cells was modified in 2010. Clinical significance of occult sentinel lymph node metastases, being mostly composed of micrometastasis and isolated tumor cells, has been clarified in terms of predictive factors for non-sentinel lymph node metastasis and patient prognosis by large-scale retrospective studies and prospective randomized clinical trials. In the present review, clinical implications of micrometastases and isolated tumor cells in sentinel lymph nodes and the methods for pathological examination of SLN metastases employed in these studies were overviewed.

Synthesis of a novel polyamidoamine dendrimer conjugating with alkali blue as a lymphatic tracer and study on the lymphatic targeting in vivo

In this study, a novel lymphatic tracer polyamidoamin-alkali blue (PAMAM-AB) was synthesized in order to evaluate the intra-lymphatic targeting ability and lymphatic tropism of PAMAM-AB after subcutaneous administration. UV-Vis, FT-IR, NMR and HPLC characterization were performed to prove the successful synthesis of PAMAM-AB. The calculated AB payload of PAMAM-AB conjugate was seven per dendrimer molecule (27.16% by weight). Hydrolysis stability of PAMAM-AB in vitro was evaluated, which was stable in PBS and human plasma. Lymphatic tracing were studied to determine the blue-stained intensity of PAMAM-AB in right popliteral lymph nodes (PLNs), iliac lymph nodes (ILNs) and para-aortic lymph nodes (PALNs) after subcutaneous administration. The pharmacokinetics and biodistribution of PAMAM-AB in mice were investigated. PLNs, ILNs and PALNs could be obviously blue-stained within 10 min after PAMAM-AB administration, and displayed a more rapid lymphatic absorption, a higher AUC value in lymph nodes and a longer lymph nodes residence time compared with methylene blue solution (MB-S), MB water-in-oil microemulsion (MB-ME), MB multiple microemulsion (MB-MME). Enhanced lymphatic drainage from the injection site and uptake into lymph of PAMAM-AB indicated that PAMAM-AB possesses the double function of lymphatic tracing and lymphatic targeting, and suggested the potential for the development of lymphatic targeting vectors or as a lymphatic tracer in its own right.

Rising Incidence Rates of Breast Carcinoma With Micrometastatic Lymph Node Involvement

We investigated the increased incidence of early-stage breast cancer with micrometastatic lymph node involvement. Breast cancer incidence trends from 1990 through 2002 in the US Surveillance, Epidemiology, and End Results Program catchment area were analyzed. Joinpoint regression was used to show the annual percentage change (APC) in breast cancer incidence trends. The overall incidence of breast cancer among women aged 50-64 years increased 1.8% (95% confidence interval [CI] = 1.4% to 2.2%) per annum from 1990 through 2002 but decreased in all other age groups. Stage IIA and stage IIB tumor incidence increased (APC for stage IIA from 1996 to 2002 = 61.9%, 95% CI = 51.1% to 73.4%, and APC for stage IIB from 1998 to 2002 = 53.7%, 95% CI = 20.6% to 96.0%). The incidence of micrometastatic lymph node involvement for stage IIA and stage IIB tumors increased during the 1990s, especially after 1997 (APC = 17.3% for both stages), more for estrogen receptor-positive than estrogen receptor-negative disease. Increased use of mammography screening partly explains the increased incidence of early-stage breast cancer. Increases in small tumors with micrometastatic lymph node involvement may be attributable to the increased use of the sentinel lymph node biopsy in community practice.

The safety and accuracy of sentinel-node biopsy in early-stage invasive breast cancer--Turkish experience

The purpose of this prospective study was to investigate the correlation of sentinel lymph node (SLN) and axillary lymph node (ALN) metastasis in early-stage invasive breast cancer in a single institution. One hundred and fifteen patients with early-stage invasive breast cancer first underwent SLND followed by an appropriate surgical procedure (modified radical mastectomy, lumpectomy + axillary dissection, simple mastectomy + mammoplasty). In this series, a radioactive agent (technetium) was used to investigate the sentinel lymph node/nodes. In 28 (24.3%) patients, metastases were found in both SLN and axillary dissections. There were no metastases in either of these procedures in 69 (60%) patients. SLN metastasis was found in 13 (11.3%) patients, but no axillary metastasis was found. No skip metastasis was detected. Five patients in whom the sentinel node was not found were also negative for axillary metastasis. As the studies progress in this direction, it might be possible to avoid axillary dissection in patients with early breast cancer in whom metastasis in SLN cannot be detected. We believe this will reduce morbidity from breast cancer surgeries.

Intraoperative evaluation of axillary sentinel lymph nodes using touch imprint cytology and immunohistochemistry: I. Protocol of rapid immunostaining of touch imprints

AIMS

Sentinel Node Biopsy (SNB) is considered an accurate method of detecting axillary lymph node status in patients with small breast cancer. Combined with an accurate and rapid histopathology tool, it could spare this group of patients unnecessary Axillary Node Clearance (ANC) with its associated hazards. Intraoperative examination of SNB for cancer cells has been investigated using both Frozen Sections (FS) and Imprint Cytology (IC) stained with different stains. This study is devoted to establish a reliable and rapid protocol for immunostaining of touch imprints from SNB.

METHODS

We investigated two different EPOS (Enhanced Polymer One-Step staining--DAKO) anticytokeratin antibodies, five different tissue fixatives and different incubation periods and temperatures with both positive and negative controls.

RESULTS

We have developed a protocol, which produced good and consistent immunostaining of touch imprints. The initial results using this protocol are concordant with those of permanent Haematoxylin and Eosin (H&E) sections.

CONCLUSIONS

We propose this protocol for rapid immunostaining of touch imprints of SNB.

Sentinel node biopsy: an in depth appraisal

Sentinel node biopsy (SNB) in primary breast cancer has been taken-up widely to avoid the morbidity attributable to axillary node clearance (ANC). Currently many issues surrounding SNB are undecided. This review summarises why some form of axillary surgery is required and presents data on all aspects of SNB including methodology, clinical results and problems that may delay the introduction of SNB as best practice for all patients with primary breast cancer. There is no long or medium term data relating to the consequences of replacing ANC with SNB, but the mechanisms and probable magnitude of both beneficial and detrimental effects are estimated. A low level of false negative results are inherent to the technique but it is demonstrated that SNB is likely to have an only marginal (0.6%) effect on survival that would be undetectable by clinical trials. Patient sub-groups particularly likely to benefit from SNB are identified.

Application of a Multigene Reverse Transcription-PCR Assay for Detection of Mammaglobin and Complementary Transcribed Genes in Breast Cancer Lymph Nodes

Background: Mammaglobin mRNA expression is found in 70–80% of primary and metastatic breast tumor biopsies. The potential breast tumor markers B305D, B726P, and γ-aminobutyrate type A receptor π subunit (GABAπ) complement the expression of mammaglobin. Collectively the expression profile of these four genes could be used as a diagnostic and prognostic indicator for breast cancer.

Methods: A multigene reverse transcription-PCR (RT-PCR) assay was established to detect the expression of mammaglobin, GABAπ, B305D, and B726P simultaneously. Specific primers and TaqMan® probes were used to analyze combined mRNA expression profiles in primary breast tumors and metastatic lymph node specimens.

Results: The multigene RT-PCR assay detected substantial expression signals in 27 of 27 primary tumor and 50 of 50 metastatic breast lymph node samples. Specificity studies demonstrated no significant expression signal in 27 non-breast cancer lymph nodes, in 22 various healthy tissue samples, or in 14 colon tumor samples.

Conclusion: The novel RT-PCR-based assay described here provides a sensitive detection system for disseminated breast tumor cells in lymph nodes. In addition, this multigene assay could also be used to test peripheral blood and bone marrow samples.

Sentinel lymph node biopsy in breast cancer: an overview of the Japanese experience

This paper reviews the Japanese literature regarding sentinel lymph node (SLN) biopsy in an attempt to provide an overview of existing controversies and to suggest a method for the identification of the SLN and the detection of micrometastases in the SLN to eliminate unnecessary axillary lymph node dissection (ALND). The combined dye- and gamma probe-guided method resulted in the accurate identification of the SLN in 96% of patients, compared with 80% when the dye-guided method alone was used. Although neither 99m-Tc sulfur colloid nor 99m-Tc colloidal albumin is commercially available in Japan, 99m-Tc stannous phytate and 99m-Tc rhenium colloid appear to be ideal tracers for identifying SLNs. Moreover, subdermal injection over the primary tumor or subareolar injection was found to enhance SLN identification, although these injection routes do not lead to detection of internal mammary SLNs. Furthermore, the accuracy of SLN diagnosis using frozen sections as well as imprint cytology improved with an increase in the number of sections, and could attain a sensitivity comparable to that obtained with routine histologic examination of permanent sections. As a result, several surgeons have begun to offer the option of forgoing ALND to patients with negative SLN. Although subsequent relapse in the axilla has not yet been reported, longer follow-up periods are needed to assess accurately the incidence of axillary failure in these negative SLN patients.

Sentinel lymph node biopsy and breast cancer

BACKGROUND AND METHOD

This paper reviews and discusses the feasibility and accuracy of sentinel lymph node (SLN) biopsy in breast cancer. A standardized method of identifying the SLN and detecting micrometastases is suggested, along with a strategy for the elimination of routine axillary lymph node dissection (ALND).

RESULTS

Although the SLN can be identified successfully by experienced practitioners using either the dye-guided or gamma probe-guided method, identification is facilitated when the two techniques are combined. To improve the likelihood of spotting metastases in the SLN, it is desirable to perform step sectioning combined with haematoxylin and eosin staining and immunohistochemistry of permanent and frozen sections. SLN biopsy is as accurate for T2 tumours as it is for T1 tumours. However, it is highly unlikely that all false-negative cases can be eliminated, even by detailed histological examination. Nevertheless, patients with T1 tumours with micrometastases in the SLN have shown no evidence of tumour in the non-sentinel nodes. In other words, ALND can be avoided in these patients, even if histological examination of the SLN fails to detect micrometastasis.

CONCLUSION

In practice, routine ALND can be avoided in patients with T1 tumours when the identified SLN proves to be histologically negative. However, investigation of long-term regional controls and of survival in a prospective randomized trial is necessary before SLN biopsy can replace routine ALND, particularly for patients with T2 tumours.

Sentinel lymph node identification and sampling in women with early breast cancer using 99m Tc labelled dextran 500 and patent blue V dye

The status of the homolateral axillary lymph nodes is still the most important prognostic factor in early stage breast cancer. The information obtained from the pathological examination of the lymph nodes guides is of critical importance in the decision process regarding the use of postoperative adjuvant therapy. However, lymph node axillary dissection can be followed by significant locoregional morbidity. The sentinel lymph node (SLN) technique was developed as a means of avoiding the full exploration of the axilla and consists in the identification of the first lymph node in the lymphatic drainage system of the breast tumour in the homolateral axilla. It has been demonstrated that the status of the SLN is highly predictive for the presence or absence of tumour involvement in the remaining lymph nodes in the axilla. In this study we evaluated the SLN technique using both 99mTc labelled dextran 500 and patent blue V dye in relation to the classical lymph node resection a series of 56 women with early breast cancer who attended the Breast Unit of the Academic Hospital of the Federal University of Rio Grande do Sul, Brazil. To our knowledge this is the first report in the literature of the utilization of 99mTc dextran 500 for the SLN technique. As there are no similar commercially available dedicated radiopharmaceuticals labelled for use in lymphoscintigraphy studies, we report on an effective method to label dextran 500 with 99mTc which proved to be simple, inexpensive and yielded similar results for SLN identification compared with those given in the literature. The median age of the patients was 57 years (range 32-82 years). Seventeen patients were age 50 years or less, and 39 patients were older than 50 years. The median tumour size was 2.0 cm (range 0.8-7.0 cm). The mapping of the SLN was possible in all cases during the transoperative period by using a hand-guided gamma probe and a blue dye. A median of 2.0 (range 1-5) SLN were excised per patient. The median of axillary lymph nodes excised per patient was 21 (range 10-36). The calculated sensitivity and specificity of the method were 95.6% and 100%, respectively. The negative predictive value and overall accuracy were 97% and 98.2%, respectively. In conclusion, the SLN technique was feasible and produced similar positive results as previously reported in the literature.

Clinical and pathologic factors predicting axillary lymph node involvement in breast cancer

The diagnosis of axillary disease remains a challenge in the management of breast cancer and is a subject of controversy. In 1998, the Japanese Breast Cancer Society conducted a study assessing axillary lymph node involvement in breast cancer. The study included (a) clinical assessment by pre-operative imaging modalities, (b) histologic assessment for peritumoral lymphatic invasion, (c) biologic assessment by gelatinolytic activity using film in situ zymography, and (d) sentinel lymph node (SLN) biopsy. Clinical assessments by CT, PET, and US as well as biologic assessment were limited in their ability to detect axillary lymph node disease, although these imaging techniques may be useful to exclude node-positive patients from the need for SLN biopsy. Histologic assessment for peritumoral lymphatic invasion was useful, particularly for detecting false-negative cases by SLN biopsy. Nevertheless, the utility of SLN biopsy in assessing axillary nodal status was confirmed. Axillary lymph node dissection (ALND) can be avoided in patients with a small tumor and a negative SLN. However, further studies will be required to investigate the value of SLN biopsy for predicting regional control and survival before it can replace routine ALND as the optimal staging procedure for operable breast cancer.

Sentinel lymph node biopsy in breast cancer using blue dye with or without isotope localization

BACKGROUND

The purpose of this study was to determine the feasibility of sentinel lymph node (SLN) biopsy using blue dye with or without isotope localization to predict the presence of axillary and internal mammary lymph node (IMN) metastases in patients with breast cancer. We also investigated whether multiple sectioning of the SLN could improve the accuracy of frozen section examination.

METHOD

One-hundred twenty-six patients underwent dye-guided or dye- and gamma probe-guided SLN biopsy followed by complete axillary lymph node dissection (ALND). No ALND was performed in the 14 patients with small tumors and a negative SLN. In addition, 69 patients underwent IMN biopsy.

RESULTS

The axillary SLN was identified in 123 of 140 (88%) patients. An accuracy rate of 90% was obtained by frozen section examination of the SLN, which increased to 100% in patients examined with a greater number of sections. Lymphatic flow to the IMN and/or a radioactive hot spot in the IMN was found in 9 of 102 (9%) patients, while a hot node was detected using a gamma probe in only 2 of these patients. No involvement of the IMNs was found histologically in these 9 patients. IMN involvement was found in 7 of 61 (11%) patients without lymphatic flow to the IMNs or a hot spot by lymphoscintigraphy or who did not undergo lymphoscintigraphy.

CONCLUSION

ALND can be avoided in patients with small breast cancers and a negative SLN. SLN biopsy guided by lymphatic mapping is unreliable for identifying metastases to IMNs.

Simultaneous immunohistochemical detection of tumor cells in lymph nodes and bone marrow aspirates in breast cancer and its correlation with other prognostic factors

PURPOSE

We studied the prognostic and predictive value of immunohistochemically detected occult tumor cells (OTCs) in lymph nodes and bone marrow aspirates obtained from node-negative breast cancer patients. All were classified as distant metastases-free using conventional staging methods.

PATIENTS AND METHODS

A total of 484 patients with pT1-2N0M0 breast cancer and 70 with pT1-2N1M0 breast cancer and a single affected lymph node participated in our trial. Ipsilateral axillary lymph nodes and intraoperatively aspirated bone marrow were examined. All samples were examined for OTCs using monoclonal antibodies to cytokeratins 8, 18, 19. Immunohistological findings were correlated with other prognostic factors. The mean follow-up was 54 +/- 24 months.

RESULTS

OTCs were detected in 180 (37.2%) of 484 pT1-2N0M0 patients: in the bone marrow of 126 patients (26.0%), in the lymph nodes of 31 patients (6.4%), and in bone marrow and lymph nodes of 23 (4.8%) patients. Of the 70 patients with pT1-2N1MO breast cancer and a single involved lymph node, OTCs were identified in the bone marrow of 26 (37.1%). The ability to detect tumor cells increased with the following tumor features: larger size, poor differentiation, and higher proliferation. Tumors of patients with OTCs more frequently demonstrated lymph node invasion, blood vessel invasion, higher urokinase-type plasminogen activator levels, and increased PAI-1 concentrations. Patients with detected OTCs showed reduced disease-free survival (DFS) and overall survival (OAS) rates that were comparable to those observed in patients who had one positive lymph node. Multivariate analysis of prognostic factors revealed that OTCs, histological grading, and tumor size are significant predictors of DFS; OTCs and grading of OAS.

CONCLUSION

OTCs detected by simultaneous immunohistochemical analysis of axillary lymph nodes and bone marrow demonstrate independent metastatic pathways. Although OTCs were significantly more frequent in patients with other unfavorable prognostic factors, they were confirmed as an independent prognostic factor for pT1-2N0M0, R0 breast cancer patients.

Sentinel lymph node biopsy as an alternative to routine axillary lymph node dissection in breast cancer patients

Sentinel lymph node (SLN) biopsy is a useful way of assessing axillary nodal status and obviating axillary lymph node dissection (ALND) in patients with node-negative breast cancer. Because SLN technology is evolving rapidly, however, variation in technique is widespread, and no standardization has yet been accomplished. This review discusses the feasibility and accuracy of this procedure and suggests the optimal method for identifying the SLN and detecting micrometastases. Although the SLN can be successfully identified by either the dye-guided or gamma probe-guided method in experienced hands, identification is facilitated when the two techniques are used together. In the gamma probe-guided method, the use of a large-sized radiotracer (particle size, 200-1000 nm) may be preferred because only one or two SLNs are identified. To increase the chance of finding metastases in SLN, it is desirable to make step sections with hematoxylin and eosin staining on permanent and frozen sections. The addition of immunohistochemistry may improve the accuracy of SLN diagnosis. The intraoperative examination of imprint cytology may be useful in determining the status of the SLNs, but further studies are needed to establish whether it has additional value when combined with the frozen section. In practice, routine ALND can be avoided when there is documentation of extensive experience and a low false-negative rate with the technique in the hands of a particular surgeon and hospital team. Particularly, SLN biopsy is more successful and has a lower false-negative rate in patients with smaller tumors. However, investigation of long-term regional control and survival in a prospective randomized trial is necessary, before SLN biopsy can replace routine ALND as the preferred staging operation for women with breast cancer.

K-ras Point Mutation Detection in Lung Cancer: Comparison of Two Approaches to Somatic Mutation Detection Using ARMS Allele-specific Amplification

Background: The use of sensitive molecular techniques to detect rare cells in a population is of increasing interest to the molecular pathologist, but detection limits often are poorly defined in any given molecular assay. We combined the approaches of real-time quantitative PCR with ARMSTM allele-specific amplification in a novel assay for detecting mutant K-ras sequences in clinical samples.

Methods: ARMS reactions were used to detect seven commonly occurring mutations in the K-ras oncogene. These mutations produce amino acid changes in codon 12 (Gly to Ala, Arg, Asp, Cys, Ser, or Val) and codon 13 (Gly to Asp). A control reaction was used to measure the total amount of amplifiable K-ras sequence in a sample so that the ratio of mutant to wild-type sequence could be measured. Quantitative data were confirmed for a selection of samples by an independent cloning and sequencing method. The assay was used to analyze 82 lung tumor DNA samples.

Results: The assay detected K-ras mutations in 44% of adenocarcinomas, which is equivalent to frequencies reported in the literature using ultrasensitive techniques. Forty-six percent of squamous carcinomas were also positive. The ratio of mutant sequence in the tumor DNA samples was 0.04–100%.

Conclusions: The assay is homogeneous, with addition of tumor DNA sample being the only step before results are generated. The quantitative nature of the assay can potentially be used to define the analytical sensitivity necessary for any specified diagnostic application of K-ras (or other) point mutation detection.

Long-term morbidity following axillary dissection in breast cancer patients--clinical assessment, significance for life quality and the impact of demographic, oncologic and therapeutic factors

OBJECTIVE

This study describes in detail the surgery-related symptoms following axillary lymph node dissection in breast cancer patients and considers both their significance for long term quality of life and the impact of possible influencing factors.

MATERIAL AND METHODS

Three hundred and ninety six patients were studied retrospectively using a self-report questionnaire and a clinical examination. The symptoms, numbness, pain, edema, arm strength and mobility were evaluated. The subjective assessment of the degree of symptom intensity was compared with objective measurements. The extent of surgery (number of resected nodes, level of dissection) as well as the influence of demographic, oncologic and adjuvant measures (age, time interval, number of involved nodes, chemotherapy) were evaluated.

RESULTS

Shoulder-arm morbidity and fear of cancer recurrence were the most important long-term sources of distress following breast cancer surgery in our study population. Demographic, oncologic and therapeutic measures including the extent of surgery had no influence on long-term morbidity. The intensity of all evaluated symptoms was reported to be more severe in patients' subjective statements than in the results of clinical assessment.

CONCLUSION

Shoulder-arm morbidity following axillary dissection is a frustrating polysymptomatic disease that seems to be relatively unaffected by therapeutic measures. The surgical trauma necessary for adequate tumor staging (removal of 10 lymph nodes) seems decisive for the postsurgery syndrome following axillary dissection. For node-positive patients complete axillary clearing may improve tumor control without worsening long-termmorbidity. New techniques, such as the sentinel-node-biopsy, that selects patients with negative axillary status while preserving the integrity of axillary structures, may improve the overall morbidity.

Pathologic analysis of the sentinel lymph node

The development of the sentinel lymph node concept has had a revolutionary effect on the way radical cancer surgery is viewed. The selective excision of the sentinel node alone has been proposed as an alternative to complete regional lymphadenectomy. This article addresses the sentinel lymph node hypothesis and the role of pathologic analysis, radiation safety, intraoperative and postoperative assessment, pathologic analysis in prognosis, and polymerase chain reaction-based studies.

Sentinel node localization in breast cancer patients using intradermal dye injection

In a series of 161 consecutive breast cancer operations, intradermal injection of Patent Blue was used to localize the sentinel node (SN). The surgical localization rate was 60%. Including the blue lymph nodes found by the pathologist, localization rate was 70%. After the first 103 operations, the surgical procedure was changed, resulting in a localization rate of 83%. Ten surgeons participated, but only one had previous experience with SN dissection. The others experienced a steep learning curve. Metastasis was found in 42 of 97 SNs (43%). In 15 cases (36%) metastasis was recognized only after step-sectioning and immunohistochemical staining for cytokeratin. In one case a benign epithelial inclusion was found. The sentinel node was false negative in 9.1% of cases. The consensus from the literature is that the best results are achieved using a combination of dye and isotopic techniques.

A multicenter validation study of sentinel lymph node biopsy by the Japanese Breast Cancer Society

Several pilot studies have indicated that SLN biopsy can be used to identify axillary lymph node metastases in patients with breast cancer. To confirm this finding, a multicenter study in a variety of practice settings was performed. A total of 674 patients with breast cancer at five institutions were enrolled. The techniques of SLN identification included the vital dye-guided and the vital dye- and gamma probe-guided methods. The SLN was removed, and complete axillary lymph node dissection (ALND) was performed. SLN and ALND specimens were examined separately. The SLN was successfully identified in 214 (94%) of 227 patients using the combined dye- and gamma probe-guided methods. The SLN was identified in 332 (74%) of 447 patients using vital dye-guided method alone. Patient age of at least 21 years, medially located primary tumor, and clinically positive nodes were correlated with failure to identify the SLN. The accuracy of SLN biopsy for the detection of metastatic disease was 96% (522 of 546), and the sensitivity was 90% (203 of 226). Accuracy of 100% was achieved in the patients with tumors less than 1.6 cm in diameter. All 23 false negative results occurred with larger primary tumors. SLN biopsy can accurately predict the presence or absence of axillary lymph node metastases, particularly in patients with small (< or = 1.5 cm) breast cancers.

Internal mammary chain sentinel lymph node identification in breast cancer

BACKGROUND AND OBJECTIVES

Sentinel lymph node (SLN) biopsy is not usually performed with respect to the internal mammary lymph node chain. However, the SLN may be located in the internal mammary chain, particularly with medial lesions. We carried out this study to investigate whether lymphatic mapping and SLN biopsy can detect internal mammary involvement in patients with breast cancer.

METHODS

A dye- and gamma probe-guided SLN biopsy was performed in a consecutive series of 41 patients with tumor in situ or clinical stage I or II breast cancer. After the biopsy, these patients underwent either a modified radical mastectomy or breast-conserving surgery including axillary lymph node dissection. Biopsy of internal mammary lymph nodes was performed in 19 of these patients.

RESULTS

No involvement of internal mammary lymph nodes was found histologically in 5 patients in whom lymphatic flow or a "hot nodule" in the internal mammary chain was found using lymphoscintigraphy. Nodal involvement was demonstrated histologically in only 1 of 5 cases where lymphatic vessels showed dye staining or faintly stained nodes. Internal mammary lymph node biopsy also was performed in 14 of 36 patients with neither stained lymphatic vessels or nodes, nor with lymphatic flow or a hot nodule by lymphoscintigraphy. Nodal involvement was found histologically in 1 of these patients.

CONCLUSION

SLN biopsy guided by lymphatic mapping is unreliable for identifying metastases to internal mammary lymph nodes.