Evaluation of axillary sentinel lymph node biopsy by immunohistochemistry and multilevel sectioning in patients with breast carcinoma

BACKGROUND: Axillary lymph node dissection for evaluation of the presence or absence of metastatic disease is the single most important prognostic factor for patients with newly diagnosed primary breast cancer. Recently, sentinel lymph node (SLN) biopsy is being investigated as an alternative to the evaluation of the entire axilla. We evaluated whether the application of multilevel sectioning and immunohistochemistry in SLNs will increase the accuracy of detection of metastatic deposits. METHODS: Between October 1998 and July 1999, 38 patients with breast carcinoma (25 ductal, 5 lobular, 4 tubular, and 4 mixed ductal and lobular) underwent successful SLN biopsy followed by complete axillary node dissection. Sentinel lymph nodes were localized with a combination of isosulfan blue dye and radionuclide colloid injection. Frozen sections and permanent sections of SLNs were examined. All negative SLNs were examined for micrometastases by 3 additional hematoxylin-eosin (H&E)-stained sections and immunohistochemistry with the cytokeratins AE1/AE3. RESULTS: Sentinel lymph nodes were successfully identified surgically in 38 (93%) of 41 patients. There was a 97% correlation between the results of the frozen sections and the permanent H&E-stained sections. Twelve (32%) of 38 patients showed evidence of metastatic disease in their SLN by routine H&E staining. In 7 (58%) of 12 patients with positive nodes, the sentinel node was the only positive node. The 26 patients with negative SLN examination by H&E were further analyzed for micrometastases; 5 (19%) were found to have metastatic deposits by immunohistochemistry. Of these patients, 2 were also converted to node positive by detection of micrometastatic disease by examination of the additional H&E levels. CONCLUSIONS: Sentinel lymph nodes can be accurately identified in the axilla of breast cancer patients. Evaluation of SLNs provides reliable information representative of the status of the axilla in these patients. Immunohistochemistry and, to a lesser degree, detailed multilevel sectioning are able to further improve our ability to detect micrometastatic disease in SLNs of breast cancer patients.     

Sentinel lymph node investigation in melanoma: detailed analysis of the yield from step sectioning and immunohistochemistry

AIMS: To evaluate in detail the extent to which step sectioning and immunohistochemical examination of sentinel lymph nodes (SLNs) in patients with melanoma reveal additional node positive patients, to arrive at a sensitive yet workable protocol for histopathological SLN examination. METHODS: The study comprised 29 patients with one or more positive SLN after a successful SLN procedure for clinical stage I/II melanoma. SLNs were lamellated into pieces of approximately 0.5 cm in size. One initial haematoxylin and eosin (H&E) stained central cross section was made for each block. When negative, four step ribbons were cut at intervals of 250 microm. One section from each ribbon was stained with H&E, and one was used for immunohistochemistry (IHC). RESULTS: When taking the cumulative total of detected metastases at level 5 as 100%, the percentage of SLN positive patients increased from 79%, 83%, 83%, 90% to 93% in the H&E sections through levels 1-5, and with IHC these values were 83%, 86%, 90%, 97%, and 100%, respectively. One of six patients in whom metastases were detected at levels 2-5 only had metastases in the subsequent additional lymph node dissection. CONCLUSIONS: Multiple level sectioning of SLNs (five levels at 250 microm intervals) and the use of IHC detects additional metastases up to the last level in melanoma SLNs. Although more levels of sectioning might increase the yield even further, this protocol ensures a reasonable workload for the pathologist with an acceptable sensitivity when compared with the published literature.     

Histopathological work-up and interpretation of sentinel lymph nodes removed for vulvar squamous cell carcinoma

Aims:  To evaluate the work-up of sentinel lymph nodes (SLNs) removed for vulvar pT1–pT2 squamous cell carcinoma (SCC). Inguinal lymphadenectomy yields metastases in only 30% of cases. Patients with missed inguinal disease, however, have a risk of dying from systemic disease. SLN dissections reduce morbidity, but work-up should reliably identify metastatic disease.
Methods and results:  All SLNs removed from 38 patients with pT1–pT2 SCC and clinically negative inguinal lymph nodes were submitted for frozen section analysis. When negative, SLN were formalin-fixed, sectioned entirely at 330-μm intervals to produce three slides per millimetre [two haematoxylin and eosin (H&E) stained slides; one slide for immunohistochemistry]. If screening of H&E-stained sections was negative, all remaining slides were subjected to immunohistochemistry with an antibody to cytokeratin. Twenty-five of 38 patients (66%) were pN0, 7/38 (18%) had metastases on frozen sections/H&E stains. Immunohistochemistry detected micrometastases in two patients and single tumour cells and anucleate cell structures in four patients. In 12/13 patients the SLN metastases, including all single-cell deposits, were from lichen sclerosus (LS)-associated SCC. Twelve of 13 patients with metastases had a pT2 SCC.
Conclusions:  Micrometastases and single tumour cell deposits in SLNs are typical of LS-associated vulvar SCC. Single tumour cell deposits in SNLs should be regarded as 'positive'. Identification requires serial sectioning and immunohistochemical analysis of all removed SLNs.     

Challenging the conventional treatment of colon cancer by sentinel lymph node mapping and its role of detecting micrometastases for adjuvant chemotherapy

All colon cancer patients with lymph node (LN) positive disease are treated with chemotherapy. Patients with node negative disease are usually cured by surgery alone. Yet about 20% of patients develop recurrence within 5 years despite node negative status. This may often be the result of missed micrometastases by conventional examination. Sentinel lymph node (SLN) mapping was developed to find those nodes detected by blue dye which was ultrastaged to detect micrometastases. Consecutive patients, underwent SLN mapping with the blue dye with success rate of 99.2%. Average number of LN was 18.3, average number of SLN was 3/patient and overall nodal positivity was 45%. Ten patients had skip metastases. Overall survival of 235 patients was 84 months with survival of node negative patients 97 months versus 68 months for node positive patients. For stage I–IV patients, overall survival was as follows: stage I—115 months, stage II—90 months, stage III—84 months and stage IV—24 months respectively. Patients with micrometastases after chemotherapy had average survival of 108 months versus those without chemotherapy was 50 months. Thus, SLN mapping techniques is highly successful, easily reproducible and finds micrmoetastases in over 15% of patients which could have been missed by conventional pathological examination. These patients when treated with adjuvant chemotherapy have similar survival as those of node negative disease. Similarly, patients without any nodal metastases after SLN mapping and ultrastaging, may be considered as true node negative disease and may avoid further adjuvant chemotherapy.     

Use of intraoperative stereomicroscopy for preventing loss of metastases during frozen sectioning of sentinel lymph nodes in breast cancer

Aims:  Optimal detection of metastases in sentinel lymph nodes (SLN) remains controversial. To determine the reliability of intraoperative frozen sections, SLN protocol with one frozen section was compared with macroscopic SLN evaluation with consecutive complete SLN embedding.
Methods and results:  SLN from 135 consecutive breast cancer patients were analysed under a sereomicroscope. Frozen sections were performed in suspicious or clearly involved SLN on cut surface. One control group ( n  = 143) underwent one intraoperative frozen section on each SLN. The second control group ( n  = 90) was subjected to stereomicroscopy and one intraoperative frozen section on each SLN. A conventional SLN protocol with cytokeratin immunohistochemistry was performed postoperatively in all cases. All groups were statistically comparable. In the study group metastases were suspected in 21 SLN (16%) under the stereomicroscope and all were confirmed histologically. The negative SLN rate was significantly lower in the study group than in the main control group (47% versus 64%, P  = 0.008), suggesting loss of metastases during frozen sections. More macrometastases were detected in the study group (30% versus 15%, P  = 0.006); there were no differences in isolated tumour cells or micrometastases. The false-negative rate was significantly lower in the control groups (29% versus 13% and 12%, P  = 0.001).
Conclusions:  Frozen sections potentially lead to loss or reduced size of metastatic deposits in SLN. Avoiding intraoperative frozen sections on grossly inconspicuous SLN may therefore be justified.     

Intraoperative sentinel lymph node evaluation in patients with node-positive breast cancer status post neoadjuvant systemic therapy - An institutional experience

Recent studies have shown the feasibility and utility of sentinel lymph node (SLN) biopsy in patients with biopsy proven node-positive breast cancer after neoadjuvant chemotherapy. We reviewed our experience in intraoperative SLN evaluation in such cases and its effect on axillary management. A retrospective analysis of breast cancer patients (2015–2018) with a biopsy-proven positive axillary lymph node, who received neoadjuvant systemic therapy and underwent intraoperative SLN assessment was performed. Intraoperative SLN assessment results were compared with final pathology. Its accuracy and effect on axillary management is summarized. We identified 106 patients with positive axillary lymph node and neoadjuvant systemic therapy between the ages of 28 and 75 years who had SLN biopsy and lumpectomy (33) or mastectomy (73). Three or more SLNs were identified in 91 cases (86 %). The previously biopsied lymph node was identified as one of the sentinel lymph nodes in 93 cases (88 %). There is a high concordance rate between frozen section diagnosis and final diagnosis on sentinel lymph nodes. No false positive case and seven false negative frozen section diagnosis cases (diagnosed as negative on frozen section and positive on permanent sections) were identified. False-negative frozen section diagnosis correlated with low-volume nodal disease and obscuring tumor bed changes. Almost half of the positive lymph nodes were converted to negative after neoadjuvant chemotherapy. SLN biopsy with intraoperative frozen section evaluation after neoadjuvant systemic therapy in node-positive patients is an effective way to minimize axillary surgery.     

乳腺癌前哨淋巴结不同转移状态下局部淋巴结成熟树突状细胞的研究

目的：研究乳腺癌前哨淋巴结不同转移状态 下前哨淋巴结与非前哨淋巴结成熟树突状细胞密度的改变。方法:回顾 性分析79例符合研究标准的女性乳腺癌患者。根据前哨淋巴结的转移状况分为3组：A组（2 8例），所有淋巴结转移阴性；B组（25例），仅微小肿瘤出现于前哨淋巴结，包括B1组（16 例），仅游离肿瘤细胞出现于前哨淋巴结；B2组（9例），仅微转移出现于前哨淋巴结；C组 （26例），转移出现于前哨淋巴结，非前哨淋巴结有或无转移。所有前哨淋巴结及非前哨淋 巴结蜡块切片均行与DC-LAMP抗体免疫反应的免疫组织学检查以确认成熟树突状细胞。蔡司 图像分析系统定量分析每个淋巴结DC-LAMP阳性细胞的相对密度（DC-LAMP阳性细胞面积/淋 巴结面积）。Wicoxon检验和Mann-Whitney检验分别用于DC-LAMP阳性细胞的相对密度的组内 和组间比较。结果:DC-LAMP阳性细胞密度的组内比较显示A组和B组前哨 淋巴结DC-LAMP阳性细胞平均密度较非前哨淋巴结高（P<0.05，P<0.01）；C组前哨淋 巴结DC-LAMP阳性细胞平均密度与非前哨淋巴结比较无明显差异（P>0.05）。组间比较 显示各组前哨淋巴结DC-LAMP阳性细胞平均密度无显著差异；而B组(尤其B2组)非前哨淋巴结 DC-LAMP阳性细胞密度较A组和C组显著升高（P<0.05，P<0.01）。结论： 前哨淋巴结和非前哨淋巴结DC-LAMP阳性细胞平均密度在淋巴结肿瘤转移形成过程发生改变,揭示前哨淋巴结在肿瘤与引流淋巴结间相互作用中起重要作用。     

Detection of micrometastases in bone marrow and sentinel lymph nodes of breast cancer patients

Objective: To study the sensitivity and clinical significance of HE-staining,IHC and RT-PCR in detecting breast cancer micrometastases in bone marrow and sentinel lymph nodes (SLNs). Methods:After general anesthesia, all patients underwent bone marrow puncture and sentinel lymph node biopsy (SLNB) by 1% isosulfan blue, and then HE-staining,IHC and RT-PCR were used to detect micrometastases. Results:Of 62 patients with breast cancer whose axillary lymph nodes showed negative HE-staining results, 15 cases presented with positive RT-PCR and 9 cases showed positive IHC results positive in bone marrow micrometastases detection. PT-PCR and IHC showed good uniformity(kappa=0.6945)and there was significant difference in detective rate between these two methods (χ2=4.1667,P=0.0412). In SLN samples, 13 showed positive RT-PCR results, while 7 showed positive IHC results. PT-PCR and IHC showed good uniformity (kappa=0.6483)and significant difference was also found in detective rate between these two methods (χ2=4.1667,P=0.0412). Both bone marrow and SLN samples were RT-PCR positive in 3 cases,which indicated that bone marrow micrometastases did not always accompany SLN micrometastases(χ2=0.067,P=0.796). Conclusion: Even if no axillary lymph node involvement or distant metastases are present in routine preoperative examination, micrometastases can still be detected in bone marrow or SLNs. Because the bone marrow micrometastases and axillary node micrometastses are not present simultaneously, combination test of multiple indicators will detect micrometastases more accurately.     

Multiparameter flow cytometry as a tool for the detection of micrometastatic tumour cells in the sentinel lymph node procedure of patients with breast cancer

AIM: To investigate whether multiparameter flow cytometry (MP-FCM) can be used for the detection of micrometastasis in sentinel lymph nodes (SLNs) in breast cancer. METHODS: Formalin fixed, paraffin wax embedded sentinel lymph nodes (n = 238) from 98 patients were analysed. For each lymph node, sections for haematoxylin and eosin (H&E) staining and immunohistochemistry (IHC) for cytokeratin (MNF116) were cut at three levels with a distance of 500 microm. The intervening material was used for MP-FCM. Cells were immunostained with MNF116, followed by an incubation with fluorescein isothiocyanate (FITC) labelled goat antimouse immunoglobulin. DNA was stained using propidium iodide. From each lymph node 100,000 cells were analysed on the flow cytometer. RESULTS: Thirty eight of the 98 patients with breast carcinoma showed evidence of metastatic disease in the SLN by one ore more of the three methods. In 37 of 38 cases where metastatic cells were seen in the routine H&E and/or IHC, more than 1% cytokeratin positive cells were detected by MP-FCM. In 24 patients, metastatic foci were more than 2 mm (macrometastasis) and in 14 these foci were smaller than 2 mm (micrometastasis). In three of these 14 cases, MP-FCM revealed positive SLNs, although this was not seen at first glance in the H&E or IHC sections. After revision of the slides, one of these three remained negative. However, MP-FCM analysis of the cytokeratin positive cells showed an aneuploid DNA peak, which was almost identical to that of the primary breast tumour. Duplicate measurements, done in 41 cases, showed a 99% reproducibility. In five of 14 patients with micrometastasis, one or two metastatic foci were found in the non-SLN. However, in 15 of 24 macrometastases multiple non-SLNs were found to have metastatic tumour. All micrometastases except for the remaining negative one mentioned above showed only diploid tumour cells, despite the fact that their primary tumours contained both diploid and aneuploid tumour cells. In primary tumours with more than 60% aneuploid cells, predominantly aneuploid macrometastasis were found, whereas diploid primary tumours only showed diploid micrometastases or macrometastases in their SLN. Aneuploid SLN macrometastases were associated with non-SLN metastases in five of seven patients, whereas diploid cases showed additional non-SLN metastases in only seven of 16 patients. CONCLUSION: In all cases, MP-FCM was sufficient to detect micrometastatic tumour cells in a large volume of lymph node tissue from SLNs. In some cases it was superior to H&E and IHC staining. Approximately 30% of SLN micrometastases are accompanied by additional non-SLN metastases. The size of the aneuploid fraction (> 60%) in the primary tumour may influence the risk of having both SLN and non-SLN metastases.     

Iatrogenically false positive sentinel lymph nodes in breast cancer: Methods of recognition and evaluation

With the introduction of sentinel lymph node (SLN) biopsy as a standard procedure for staging clinically node negative breast cancer patients, meticulous pathologic evaluation of SLNs by serial sections and/or immunohistochemistry for cytokeratins has become commonplace in order to detect small volume metastases (isolated tumor cells and micrometastases). This practice has also brought to the fore the concept of iatrogenically false positive sentinel nodes secondary to epithelial displacement produced largely by preoperative needling procedures. While this concept is well described in the clinical and pathologic literature, it is, in our experience, still under-recognized, with such lymph nodes frequently incorrectly diagnosed as harboring true metastases, possibly resulting in unwarranted further surgery and/or chemotherapy. This review discusses the concept of displaced epithelium in the histologic evaluation of breast surgical specimens and provides a stepwise approach to the correct identification of iatrogenically transported displaced epithelial cells in sentinel lymph nodes.     

Reliability of intraoperative frozen section and imprint cytological investigation of sentinel lymph nodes in breast cancer

AIMS: The sentinel lymph node procedure enables selective targeting of the first draining lymph node, where the initial metastases will form. A negative sentinel node (SN) predicts the absence of tumour metastases in the other regional lymph nodes with high accuracy. This means that in the case of a negative SN, regional lymph node dissection is no longer necessary. Besides saving costs, this will prevent many side-effects of lymph node dissection. The aim of this study was to evaluate the reliability of intraoperative cytological and frozen section investigation of the SN to detect metastases. This would allow the axillary lymph node dissection to be performed in the same session as the SN procedure and the excision of the primary tumour in case of a positive SN. METHODS AND RESULTS: Seventy-four SNs were detected by gamma probe detection of nanocolloid and visual localization of Patent Blue accumulations in 54 women with stage T1-2N0M0 invasive breast cancer. The identified SN were immediately investigated by frozen section and imprint cytological investigation. Diagnoses were confirmed on the paraffin material, and in case of negative frozen section and paraffin haematoxylin and eosin sections, skip sections and immunohistochemistry were performed. Thirty-one SNs (42%) contained metastases, of which 27 were detected by the frozen section procedure (sensitivity 87%). There were no false positives (specificity 100%). The sensitivity of the imprints was 62% with a specificity of 100%. When evaluating the data per patient, for the frozen section procedure the sensitivity was 91% and the specificity 100%, and for the imprints, the sensitivity was 63% and the specificity 100%. There were no SNs in which the imprints showed metastases and the frozen section did not. CONCLUSIONS: Intraoperative frozen section analysis is a reliable procedure by which a high percentage of sentinel lymph node metastases can be detected in breast cancer patients without false positive results. This allows the surgeon to perform an immediate axillary lymph node dissection in case of positive SNs. In up to 10% of cases, the final paraffin sections will reveal micrometastases that were not detected by the frozen section, and in these patients axillary lymph node dissection will have to be performed in a second session. The imprint method is significantly less sensitive than the frozen section but may be used as an alternative when frozen section is not possible.     

Modes of benign mechanical transport of breast epithelial cells to axillary lymph nodes

The status of axillary lymph nodes is a key prognostic indicator available for the management of patients with breast cancer. Sentinel lymph node (SLN) evaluation as a predictor of lymph node status has led to increased use of ancillary methods, principally immunohistochemistry, to increase the sensitivity of the SLN biopsy. So-called "occult" micrometastases detected by such methods have led to speculation that some may have reached the SLNs by benign mechanical transport (BMT) rather than a metastatic process. We review evidence suggesting two potential modes of BMT: lymphatic transport of epithelial cells displaced by biopsy of the primary breast tumor and by breast massage-assisted SLN localization. The biopsy techniques under most scrutiny include fine needle aspiration and large-gauge core biopsy. The evidence implicating breast massage prior to SLN biopsy as a mode of BMT has been supported by statistical analysis; however, no method of distinguishing massage-associated cells in SLNs from true occult micrometastases is available. The significance of small epithelial clusters in SLNs is currently unknown. Thus, deviation from current biopsy and SLN-localizing practices is unwarranted.     

Can immunohistochemistry enhance the detection of micrometastases in pelvic lymph nodes from patients with high-grade urothelial carcinoma of the bladder?

Immunohistochemistry for keratin has enhanced our ability to detect micrometastases in certain cancer patients with negative lymph nodes by routine histologic examination of H&E-stained sections. However, there is no information about micrometastasis of bladder cancer. We performed immunohistochemistry for keratins on 159 pelvic lymph nodes, which were negative for metastatic tumors on routine H&E-stained sections, from 19 patients with high-grade muscle invasive urothelial bladder cancer. In 1 man, 1 lymph node contained a keratin-positive micrometastasis that was not present on the original H&E-stained slide. However, the metastasis was seen readily on a new H&E-stained section prepared from the paraffin block adjacent to the keratin-stained section. Immunohistochemical analysis for keratins revealed no additional case of micrometastasis of urothelial carcinoma of the bladder. The perinodal fibroadipose tissue of a lymph node from a woman contained a few keratin-positive benign glands of endosalpingiosis. A thorough examination of the H&E-stained sections is the best method for detecting lymph node metastases of urothelial carcinoma from the bladder. There is a potential risk for misdiagnosis of metastases by using immunohistochemistry or polymerase chain reactions for keratins because of the occasional presence of benign epithelial cells in pelvic lymph nodes and associated connective tissue.     

Comparison of pathologist-detected and automated computer-assisted image analysis detected sentinel lymph node micrometastases in breast cancer.

Sentinel lymph node biopsy has stimulated interest in identification of micrometastatic disease in lymph nodes, but identifying small clusters of tumor cells or single tumor cells in lymph nodes can be tedious and inaccurate. The optimal method of detecting micrometastases in sentinel nodes has not been established. Detection is dependent on node sectioning strategy and the ability to locate and confirm tumor cells on histologic sections. Immunohistochemical techniques have greatly enhanced detection in histologic sections; however, comparison of detection methodology has not been undertaken. Automated computer-assisted detection of candidate tumor cells may have the potential to significantly assist the pathologist. This study compares computer-assisted micrometastasis detection with routine detection by a pathologist. Cytokeratin-stained sentinel lymph node sections from 100 patients at the University of Vermont were evaluated by automated computer-assisted cell detection. Based on original routine light microscopy screening, 20 cases that were positive and 80 cases that were negative for micrometastases were selected. One-level (43 cases) or two-level (54 cases) cytokeratin-stained sections were examined per lymph node block. All 100 patients had previously been classified as node negative by using routine hematoxylin and eosin stained sections. Technical staining problems precluded computer-assisted cell detection scanning in three cases. Computer-assisted cell detection detected 19 of 20 (95.0%; 95% confidence interval, 75-100%) cases positive by routine light microscopy. Micrometastases missed by computer-assisted cell detection were caused by cells outside the instrument's scanning region. Computer-assisted cell detection detected additional micrometastases, undetected by light microscopy, in 8 of 77 (10.4%; 95% confidence interval, 5-20%) cases. The computer-assisted cell detection-positive, light microscopy-missed detection rate was similar for cases with one (3 of 30; 10.0%) or two (5 of 47; 10.6%) cytokeratin sections. Metastases detected by routine light microscopy tended to be larger (0.01-0.50 mm) than did metastases detected only by computer-assisted cell detection (0.01-0.03 mm). In a selected series of patients, automated computer-assisted cell detection identified more micrometastases than were identified by routine light microscopy screening of cytokeratin-stained sections. Computer-assisted detection of events that are limited in number or size may be more reliable than detection by a pathologist using routine light microscopy. Factors such as human fatigue, incomplete section screening, and variable staining contribute to missing metastases by routine light microscopy screening. Metastases identified exclusively by computer-assisted cell detection tend to be extremely small, and the clinical significance of their identification is currently unknown.     

CK19表达及其在喉鳞癌淋巴结微转移诊断中的应用

目的:研究用免疫组化方法检测CK19及其在喉鳞癌淋巴结微转移诊断中应用与临床病理意义。方法:对40例喉鳞癌患者及清扫淋巴结163个(常规临床检查颈部淋巴结阴性pN₀)进行常规病理检查(HE染色)和抗角蛋白19抗体的免疫组化检测。结果:40例喉鳞癌组织中CK19均表达阳性,40例颈淋巴结常规病理检查(HE染色)发现5例有转移者(共23枚淋巴结),CK19检测也为阳性。19个淋巴结常规病理检查未发现转移者,CK19也表达阳性。随着肿瘤T分期的增加,淋巴结CK19表达阳性率亦增加。CK19表达阳性者预后较阴性者差。结论:CK19免疫组化法是检测喉鳞癌淋巴结微转移的敏感而便捷的方法,而检测喉鳞癌微转移有助于判断肿瘤进展程度与预后,特别对筛选组织学检查淋巴结阴性但存在微转移的病人有实用价值。     

Update on sentinel node pathology in breast cancer

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

Intraoperative examination of the sentinel lymph node for breast carcinoma staging.

Intraoperative pathologic examination of the sentinel lymph node (SLN) draining a primary breast carcinoma allows an SLN-positive patient to undergo complete axillary lymphadenectomy as part of the same surgical procedure. However, the optimal technique for rapid SLN assessment has not been determined. We reviewed our results with imprint cytology (IC) and frozen section (FS) examination of SLNs from 278 patients. Compared with H&E-stained paraffin sections, IC and FS had an overall accuracy of 93.2%. The false-reassurance rate (false-negative results/all negative results) was 8.4%. It correctly identified 98% of macrometastases but only 28% of micrometastases. There were no false-positive results. Compared with paraffin-section cytokeratin immunohistochemistry results, the IC-FS false-reassurance rate increased to 25.8%. The false-reassurance rate decreased with smaller primary tumor size (T1 vs T2/3) and ductal type, smaller diameter of the SLN (< or = 2.0 cm), and greater pathologist experience. IC combined with 2-level FS reliably identifies SLN macrometastases but commonly fails to detect SLN micrometastases. If SLN micrometastasis is used to determine the need for further lymphadenectomy, more sensitive intraoperative methods will be needed to avoid a second operation.     

Intraoperative evaluation of axillary lymph nodes for micrometastases using immunohistochemistry--preliminary study

The increase of utilization of sentinel lymph nodes concept for breast carcinoma has made intraoperative evaluation of immunohistochemistry using epithelial markers attractive. At present the optimal procedures for intraoperative detection of micrometastasis of axillary lymph nodes has not been established. The purpose of this study is to evaluate the immunohistochemistry for intraoperative diagnosis of axillary lymph nodes in patients with breast cancer. Lymph nodes from 170 patients(1048 lymph nodes) were examined immunohistochemistry using anti cytokeratin, compared with intraoperative frozen section of same lymph nodes with H & E staining. Tumor metastases were found in 50 patients(92 lymph nodes) in H & E staining section, compared with 64 patients(113 lymph nodes) stained with anti-cytokeratin. Of 14 patients whose metastases were detected by immunohistochemistry. Routine intraoperative frozen diagnosis using H & E stainings significantly underestimates lymph nodes metastases. The insufficient diagnosis may be overcome by immunohistochemistry using anti-cytokeratin and careful examination of routine sections with good qualities. The true clinical significance of these micrometastases will be determined by long term follow up studies.     

Non-sentinel lymph node involvement in patients with breast cancer and sentinel node micrometastasis; too early to abandon axillary clearance

AIMS: It has been suggested that patients with T1-2 breast tumours and sentinel node (SLN) micrometastases, defined as foci of tumour cells smaller than 2 mm, may be spared completion axillary lymph node dissection because of the low incidence of further metastatic disease. To gain insight into the extent of non-sentinel lymph node (n-SLN) involvement, SLNs and complementary axillary clearance specimens in patients with SLN micrometastases were examined. METHODS: A set of 32 patients with SLN micrometastases was selected on the basis of pathology reports and review of SLNs. Five hundred and thirteen n-SLNs from the axillary clearance specimens were serially sectioned and analysed by means of immunohistochemistry for metastatic disease. Lymph node metastases were grouped as macrometastases (> 2 mm), and micrometastases (< 2 mm), and further subdivided as isolated tumour cells (ITCs) or clusters. RESULTS: In 11 of 32 patients, one or more n-SLN was involved. Grade 3 tumours and tumours > 2 cm (T2-3 v T1) were significantly associated with n-SLN micrometastases as clusters (grade: odds ratio (OR), 8.3; 95% confidence interval (CI), 1.4 to 50.0; size: T2-3 tumours v T1: OR, 15; 95% CI, 2.18 to 103.0). However, no subgroup of tumours with regard to size and grade was identified that did not have n-SLN metastases. CONCLUSIONS: In patients with breast cancer and SLN micrometastases, n-SLN involvement is relatively common. The incidence of metastatic clusters in n-SLN is greatly increased in patients with T2-3 tumours and grade 3 tumours. Therefore, axillary lymph node dissection is especially warranted in these patients. However, because n-SLN metastases also occur in T1 and low grade tumours, even these should be subjected to routine axillary dissection to achieve local control.     

Analysis of sentinel node biopsy - a single-institution experience supporting the use of serial sectioning and immunohistochemistry for detection of micrometastases by comparing four different histopathological laboratory protocols

Grabau D, Ryden L, Fernö M & Ingvar C
(2011) Histopathology 59 , 129–138 Analysis of sentinel node biopsy – a single‐institution experience supporting the use of serial sectioning and immunohistochemistry for detection of micrometastases by comparing four different histopathological laboratory protocols Aims: Detecting micrometastases (>0.2 and ≤2 mm/>200 cells) and isolated tumour cells (ITCs; ≤0.2 mm/<200 cells) is important for staging of breast cancer patients. The aim of this study was to systematically compare several laboratory protocols used to detect metastases after initial intraoperative frozen section examination. Methods and results: Four different protocols for the work‐up of sentinel lymph nodes (SLNs) after frozen sectioning were applied in the routine diagnostic process from 2001 to 2009. In addition, team‐work with a limited number of laboratory technicians and pathologists handling SLNs was introduced in 2008. The present study shows that there were, overall, significantly more node‐positive patients in the period when team‐work and intensive step sections including immunohistochemistry (IHC) were used (P = 0.01). This resulted in 13% more patients being found to have ITCs and micrometastases than in a time period when only step sections were performed. No increase in the number of false‐negative frozen sections was seen. Conclusions: Future guidelines for pathological work‐up of sentinel nodes in women with breast cancer might include team‐work and IHC if frozen sections are used intraoperatively.