乳腺癌内乳区淋巴结诊疗的研究进展

内乳区淋巴结（internal mammary lymph node,IMLN）引流整个乳腺约25%的淋巴液,其转移状况为乳腺癌预后指标之一,也是确定分期和制定治疗方案的重要依据。内乳区前哨淋巴结活检术（internal mammary-sentinel lymph node biopsy,IM-SLNB）作为微创诊断技术实现对IMLN的评估,有助于为患者制定更为准确的个体化治疗方案。在乳晕周围腺体内增加注射部位和注射剂量的新型注射技术显著提高内乳区前哨淋巴结（internal mammary sentinel lymph node,IMSLN）检出率,使得常规开展IM-SLNB成为可能。随着内乳区淋巴引流规律的深入研究,新型注射技术引导下的IM-SLNB的准确性目前已得到初步验证。本文将对乳腺癌内乳区淋巴结诊疗的研究进展进行综述。      

乳腺癌内乳前哨淋巴结活检评估预后及指导个体化内乳照射：一项长期随访研究

背景与目的：内乳照射（internal mammary lymph node irradiation,IMNI）可以改善内乳淋巴结（internal mammary lymphnode,IMLN）高危转移患者的生存。本研究旨在探讨内乳前哨淋巴结活检（internalmammarysentinellymphnode biopsy,IM-SLNB）对评估预后及指导个体化IMNI的优势。方法：回顾性分析2011年11月—2021年12月在3项前瞻性临床试验（NCT01642511、NCT03541278、NCT03024463）中成功行IM-SLNB的浸润性乳腺癌患者，筛选预后的独立危险因素，分析内乳前哨淋巴结（internal mammary sentinel lymph node,IMSLN）转移对预后的影响；在接受区域淋巴结照射者中分析IMNI实施状况、生存获益及对放射性肺损伤（radiation induced lung injury,RILI）的影响。主要研究终点为无病生存期（disease-free survival,DFS），次要研究终点为总生存期（overall surviv...     

乳腺癌前哨淋巴结活检假阴性原因研究新进展

乳腺癌根治术常规进行腋窝淋巴结清扫术,往往给患者造成疼痛、水肿、运动和感觉功能障碍。前哨淋巴结活检(sentinel lymph node biopsy,SLNB)是一种微创的淋巴结活检方法,用前哨淋巴结评估整个腋窝淋巴结转移情况,有针对性的指导清扫腋窝淋巴结,减小清扫范围,减轻患者腋窝淋巴结清扫后遗症,但是前哨淋巴结活检存在一定比例的假阴性结果,影响其在临床的推广,主要原因有:适应证的选择不当、术前化疗影响、对内乳前哨淋巴结忽略、分子病理学方法利用不充分、单用示踪剂等。增强临床医生和病理医生对乳腺癌前哨淋巴结活检的临床指导作用以及腋窝淋巴结和内乳淋巴结解剖变异的认识,加强SLNB规范操作,借助术中冰冻切片,联合免疫组化,RT-PCR等方法,可降低SLNB假阴性率。     

简化腋窝淋巴结清扫术在早期乳腺癌治疗中的应用

目的探讨简化腋窝淋巴结清扫术(axillary lymph node dissection,ALND)在乳腺癌手术中的应用及效果。方法分析2009年1月至2013年6月间行前哨淋巴结活检(sentinel lymph node biopsy,SLNB)327例乳腺癌患者的临床资料,行亚甲蓝染色法SLNB后根据前哨淋巴结(sentinel lymph node,SLN)冰冻病理结果,对SLN阳性者行规范的ALND,SLN阴性则行简化的ALND(只清扫LevelⅠ),比较两组在手术时间、术后住院时间、腋窝引流时间及术后并发症的差异。结果 327例患者中,314例成功进行了SLNB,119例SLN阳性者行标准的ALND,195例SLN阴性者行简化的ALND,11例SLN阴性患者出现LevelⅠ组织淋巴结转移;简化组手术时间、术后住院时间、腋窝引流时间明显缩短,术后腋窝积液、肌力减退、活动受限、疼痛、麻木、肿胀等并发症明显减少。术后随访3~60个月,患者无腋窝淋巴结复发及远处转移。结论蓝染法SLNB是乳腺癌患者腋窝淋巴结转移状态的重要检测技术,对SLN阴性行简化的ALND,可节省医疗资源、减少术后并发症。     

乳腺癌新辅助化疗后腋窝及内乳前哨淋巴结活检研究

背景与目的：临床新辅助化疗(neoadjuvant chemotherapy,NAC)后腋窝淋巴结(axillary lymph node,ALN)转阴的患者腋窝前哨淋巴结活检(axillary sentinel lymph node biopsy, ASLNB)能否替代腋窝淋巴结清扫(axillary lymph node dissection,ALND)尚存在争议,且此前研究只评估ALN病理状况而未评估内乳淋巴结(internal mammary lymph node,IMLN)状况。本研究旨在评估NAC后乳腺癌患者接受ASLNB和内乳前哨淋巴结活检(internal mammary sentinel lymph node biopsy,IM-SLNB)的临床意义。方法：回顾性分析2012年1月—2014年12月山东省肿瘤医院乳腺病中心原发性乳腺癌(cT_1-4N_0-3M₀)60例患者的临床资料,将患者分为3组：A组初始cN₀且NAC后为ycN₀,B组初始cN+且NAC后为ycN₀,C组NAC后为ycN₊。术前接受核素注射。术中A组和B组联合亚甲蓝行ASLNB。A组仅对腋窝前哨淋巴结(axillary sentinel lymph node,ASLN)阳性者行ALND;B组行ASLNB后转行ALND;C组直接行ALND。术前淋巴显像和(或)γ探测仪发现内乳前哨淋巴结(internal mammary sentinel lymph node,IM-SLN)的患者行IM-SLNB。结果：A组、B组和C组分别收集6例、45例和9例。A组ASLNB成功率为100%(6/6),仅1例ASLN阳性转行ALND。B组ASLNB成功率为100%(45/45),假阴性率为17.9%(5/28)。其中检出1枚、2枚和＞2枚ASLN的假阴性率分别为27.3%(3/11)、20.0%(2/10)和0%(0/7)。C组所有患者ALN均有转移。IM-SLN总体显像率为63.3%(38/60)。IM-SLNB的总体成功率为97.4%(37/38),转移率为8.1%(3/37),并发症发生率为5.3%(2/38)。结论：对初始cN₀且NAC后为ycN₀者ASLN阴性时ASLNB可替代ALND;对初始cN₊且NAC后为ycN₀者,联合双示踪剂且检出＞2枚ASLN可满足临床可接受的假阴性率(<10%);对NAC后仍为ycN₊者应行ALND。NAC后IM-SLN显像者应行IM-SLNB,以获得完整分期、评估预后并指导术后放疗,有望完善病理完全缓解(pathological complete response,pCR)定义。     

染色法乳腺癌前哨淋巴结活检的临床应用价值

[目的]探讨染色法乳腺癌前哨淋巴结(sentinel lymph node,SLN)活检对腋淋巴结(axillary lymph node,ALN)转移预测的准确性.[方法]采用亚甲蓝染色法对50例乳腺癌行腋窝蓝染淋巴结活检,后行常规腋窝淋巴结清扫,两标本均送病理检查.[结果]全组50例患者检出SLN 48例,2例未找到SLN,检出率为96%(48/50);SLN与ALN病理检查完全符合者47例,准确率为97.9%(47/48);灵敏度为88.9%(8/9);假阴性率为11.1%(1/9).[结论]前哨淋巴结活检能准确预测乳腺癌腋窝淋巴结状态,亚甲蓝染色法可以成功确定SLN.     

前哨淋巴结活检术在早期乳腺癌保乳术中的应用

目的探讨前哨淋巴结活检术（sentinellymph node biopsy,SLNB）在早期乳腺癌保乳术中的应用效果。方法回顾性分析56例pT1.2N0M0期乳腺癌行保乳术＋前哨淋巴结活检术的临床资料。56例SLN阴性,未行腋窝淋巴结清扫术（axillary lymph node dissection,ALND）。术后辅以化疗、放疗,激素受体阳性患者行内分泌治疗。结果56例成功施行保乳手术,保乳术后双乳对称。SLNB替代ALND者各项术后并发症少。中位随访时间36个月（1～72个月）,1例发现局部复发,行乳腺癌改良根治术时发现腋窝淋巴结转移;1例发现腋窝淋巴结复发转移。结论SLNB可以缩小手术范围,减少术后并发症,保留腋窝形态,提高保乳质量。     

乳腺癌内乳前哨淋巴结活检核素示踪技术优化研究

背景与目的：山东省肿瘤防治研究院（山东省肿瘤医院）乳腺病中心前期研发新型核素示踪技术，显著提高了内乳前哨淋巴结（internal mammary sentinel lymph node,IMSLN）显像率，但该技术获得的IMSLN显像率相较于腋窝前哨淋巴结（axillary sentinel lymph node,ASLN）仍然存在一定差距。本研究旨在通过优化新型核素示踪技术，进一步提高IMSLN显像率，推动内乳前哨淋巴结活检（internal mammary sentinel lymph node biopsy,IM-SLNB）广泛应用。方法：前瞻性入组159例原发性乳腺癌患者，分为优化核素示踪技术组（n=81,A组）和新型核素示踪技术组（n=78,B组）。A组在超声引导下将99mTc-硫胶体平均注射在腺体最丰富的3个区域腺体实质内（总放射强度1.0～1.3mCi;0.8～1.0mL/点）。B组在超声引导下将99mTc-硫胶体平均注射在乳腺6点和12点腺体实质内（总放射强度1.0～1.3mCi;0.8～1.0mL/点）。术前进行单光子发射计算机断层扫描（single photon e...     

早期乳腺癌腋窝亚LevelⅡ淋巴结清扫的初步研究

目的：探索基层医院早期乳腺癌腋窝淋巴结外科处理的适宜方法。方法：对9例符合研究条件的病例先美兰染色（meythylene blue staining）实施前哨淋巴结活检（sentinel lymph node biopsy,SLNB）,再补充实施腋窝淋巴结清扫术（axillary lymph node dissection,ALND）;ALND术中显露腋静脉,以腋静脉下2cm为界缝线标记,术后将标本从缝线处分离,对淋巴结进行分组取材,将前哨淋巴结、腋静脉下2cm内淋巴结（亚levelⅡ淋巴结）、腋窝其余淋巴结（其余淋巴结）分组送病理检查,观察各组淋巴结数量及肿瘤细胞腋淋巴结转移规律。结果：找到前哨淋巴结6例;5例前哨淋巴结、亚levelⅡ淋巴结、其余淋巴结均为阴性;1例前哨淋巴结、亚levelⅡ淋巴结、其余淋巴结均为阳性;另有1例患者前哨淋巴结未找到,而亚levelⅡ淋巴结检出阳性。结论：基层医院对于早期乳腺癌腋窝淋巴结清扫,可以用美兰染色行前哨淋巴结活检,若前哨淋巴结阳性或未找到前哨淋巴结,行ALND;若前哨淋巴结阴性,行亚levelⅡ淋巴结清扫。     

早期乳腺癌腋窝亚LevelⅡ淋巴结清扫的初步研究

目的:探索基层医院早期乳腺癌腋窝淋巴结外科处理的适宜方法。方法:对9例符合研究条件的病例先美兰染色(meythylene blue staining)实施前哨淋巴结活检(sentinel lymph node biopsy,SLNB),再补充实施腋窝淋巴结清扫术(axillary lymph node dissection,ALND);ALND术中显露腋静脉,以腋静脉下2cm为界缝线标记,术后将标本从缝线处分离,对淋巴结进行分组取材,将前哨淋巴结、腋静脉下2cm内淋巴结(亚levelⅡ淋巴结)、腋窝其余淋巴结(其余淋巴结)分组送病理检查,观察各组淋巴结数量及肿瘤细胞腋淋巴结转移规律。结果:找到前哨淋巴结6例;5例前哨淋巴结、亚levelⅡ淋巴结、其余淋巴结均为阴性;1例前哨淋巴结、亚levelⅡ淋巴结、其余淋巴结均为阳性;另有1例患者前哨淋巴结未找到,而亚levelⅡ淋巴结检出阳性。结论:基层医院对于早期乳腺癌腋窝淋巴结清扫,可以用美兰染色行前哨淋巴结活检,若前哨淋巴结阳性或未找到前哨淋巴结,行ALND;若前哨淋巴结阴性,行亚levelⅡ淋巴结清扫。     

Internal mammary lymph drainage and sentinel node biopsy in breast cancer – A study on 1008 patients

Introduction

Nowadays, axillary sentinel node (SN) biopsy is a standard procedure in the staging of breast cancer. Although the internal mammary (IM) lymph node status is a major independent prognostic factor in breast cancer patients, sampling of IM sentinel nodes (IMSNs) is not performed routinely. The aim of this study was to determine the likelihood of finding IM lymph node metastases in case of IM hotspots on lymphoscintigraphy and evaluate the relevance of IMSN biopsy as a method to improve staging.

Patients and methods

Between April 1997 and May 2006, a total of 1008 consecutive patients with clinically node-negative operable primary breast cancer were enrolled in a prospective study on SN biopsy. Both axillary and IMSNs were sampled, based on lymphoscintigraphy, intraoperative gamma probe detection and blue dye mapping, using 10 mCi (370 MBq) ^99mTc-nanocolloid injected peritumorally, and 0.5–1.0 ml Patent Blue V injected intradermally.

Results

Lymphoscintigraphy showed axillary sentinel nodes in 98% (989/1008) and IMSNs in 20% of the patients (196/1008). Sampling the IM basin, as based on the results of lymphoscintigraphy, was successful in 71% of the patients (139/196) and revealed metastases in 22% (31/139). In 29% of the patients with positive IMSNs (9/31) no axillary metastases were found.

Conclusion

Evaluation of IMSNs improves nodal staging in breast cancer. Patients with IM hotspots on lymphoscintigraphy have a substantial risk (22%) of metastatic involvement of the IM chain. In addition, true IM node-negative patients can be spared the morbidity associated with adjuvant radiotherapy.     

The role of internal mammary lymph node metastases in the management of breast cancer

We reviewed the literature regarding internal mammary lymph node metastasis in the management of breast cancer. Internal mammary dissection or radiotherapy provides no survival advantage in breast cancer patients. However, internal mammary nodal metastasis is an important independent prognostic factor. Patients with such metastases are candidates for systemic adjuvant hormonal therapy and/or chemotherapy. Moreover, in patients with histologically confirmed internal mammary metastases, irradiation of the nodes is appropriate for local control. Noninvasive techniques, such as internal mammary lymphoscintigraphy, parasternal sonography, computed tomography, and magnetic resonance imaging, are not satisfactory for the practical diagnosis of internal mammary metastasis. At present, biopsy of the internal mammary nodes in the first and second intercostal spaces is indicated for assessing nodal status and planning treatment.     

A selection algorithm for internal mammary sentinel lymph node biopsy in breast cancer.

Internal mammary lymph-node (IMN) metastases in breast carcinomas have a major influence on survival, comparable with the influence of axillary lymph-node metastases (ALNM). Prospective, randomized trials have demonstrated that complete IMN dissection as part of extended radical mastectomy does not improve overall or disease-free survival. In the subset of patients with tumours 1cm or less in size and no ALNM, information on IMN status would provide important information. In these cases, the presence of IMN metastases would change the staging from stage I to stage IIIB, according to the current tumour, node and metastasis classification. More importantly, it would influence these patients' adjuvant treatment. Lymphatic mapping for sentinel lymph-node (SLN) biopsy has demonstrated extra-axillary drainage in up to 35% of patients. Recent reports have demonstrated the feasibility of internal mammary sentinel lymph-node (IM-SLN) biopsy. Here we review the general prognostic and clinical significance of tumor location and lymph-node metastases in breast cancer and discuss the specific factors associated with IMN identification, metastases and treatment in the pre-SLN and SLN eras. Based on our review, we propose an algorithm for a selective approach to IM-SLN in breast cancer.     

Internal mammary node metastasis in breast cancer: Predictive models to determine status & management algorithms

Aim

Internal mammary node (IMN) metastases are an important prognostic factor in breast cancer. However due to difficulty of access, most surgeons ignore these nodes, hence adjuvant treatment decisions may be compromised. Through mathematical modeling based on large datasets this study aims to estimate the current rate of IMN and sentinel node metastasis.

Methods

Models were created to estimate the current rate of axillary and IM sentinel node metastasis. Data from historical extended radical mastectomy series were analyzed to project contemporary rates of IMN metastasis. This information was coupled with derived models and contemporary datasets: a single-institution breast lymphoscintigraphy database (1992–2007) to establish lymphatic anatomy; and the Surveillance, Epidemiology and End-Results (SEER) registries in the US (2000–2003).

Results

Rates of IMN metastasis and positive sentinel nodes were estimated and models derived to assist with predicting IMN status in patients. If high definition peritumoral lymphatic mapping were available, the predicted rates of positive sentinel nodes in the axilla (AN) and internal mammary chain (IMN) would be equal. We predicted the overall rate of IMN metastasis is ∼39% the rate of positive sentinel AN.

Conclusion

Simplified models and algorithms can predict IMN status.     

乳腺癌前哨淋巴结CK19 mRNA和蛋白的表达

目的 探讨CK19微转移分子在乳腺癌前哨淋巴结(SLN)的表达情况及意义.方法 采用免疫组化S-P法及原位杂交技术检测66例SLN中CK19微转移分子的表达.同时与常规病检法比较其检测敏感性.并比较转移组、微转移组、无转移组患者的临床资料.结果 66例SLN在常规病理检查阴性38例淋巴结中6例表达CK19蛋白15.8%(6/38),8例21.1%(8/38)表达CK19mRNA.原位杂交法与常规病检法转移的检出率相比较,差异有统计学意义(P＜0.05).CK19蛋白和mRNA表达之间差异无统计学意义(P＞0.05).同时乳腺癌转移组与微转移组患者在肿物大小与淋巴管浸润上有相似性,而同无转移组差异有统计学意义(P＜0.05).结论 免疫组化法和原位杂交法较常规病理检查更为敏感.通过免疫组化法和原位杂交法的联合使用,可明显提高乳腺癌SLN微转移的检出率,同时也证明原位杂交法是可靠的,比免疫组化更为敏感的技术.SLN微转移有可能作为肿瘤预后的指标.     

Role of FDG PET-CT in evaluation of locoregional nodal disease for initial staging of breast cancer

Fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) is not indicated or recommended in the initial staging of early breast cancer. Although it is valuable for detecting distant metastasis, providing prognostic information, identifying recurrence and evaluating response to chemotherapy, the role of FDG PET/CT in evaluating locoregional nodal status for initial staging of breast cancer has not yet been well-defined in clinical practice. FDG PET/CT has high specificity but compromised sensitivity for identifying axillary nodal disease in breast cancer. Positive axillary FDG PET/CT is a good predictor of axillary disease and correlates well with sentinel lymph node biopsy (SLNB). FDG PET/CT may help to identify patients with high axillary lymph node burden who could then move directly to axillary lymph node dissection (ALND) and would not require the additional step of SLNB. However, FDG PET/CT cannot replace SLNB or ALND due to unsatisfactory sensitivity. The spatial resolution of PET instruments precludes the detection of small nodal metastases. Although there is still disagreement regarding the management of internal mammary node (IMN) disease in breast cancer, it is known that IMN involvement is of prognostic significance, and IMN metastasis has been associated with higher rates of distant metastasis and lower overall survival rates. Limited clinical observations suggested that FDG PET/CT has advantages over conventional modalities in detecting and uncovering occult extra-axillary especially IMN lesions with upstaging the disease and an impact on the adjuvant management.     

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.     

核素淋巴显像识别前哨淋巴结在乳腺癌治疗中的应用

目的评价核素淋巴显像和γ探针定位在乳腺癌中确定前哨淋巴结(SLN)的应用价值,验证前哨淋巴结活检替代腋窝淋巴结清除术用于乳腺癌治疗的安全性与价值。方法选择1999年6月至2009年11月本院住院的女性乳腺癌患者206例(体检时腋窝均未扪及肿块),应用99Tcm-DX37～74 MBq或99Tcm-SC74 MBq经皮下注射,行核素淋巴显像后,术中注射专利兰1 ml和(或)术中用γ探针定位并行前哨淋巴结活检,与术中冰冻病理检查结果对照。若术中冰冻发现有前哨淋巴结转移,则行腋窝淋巴结清除术,若前哨淋巴结阴性,则不做腋窝淋巴结清除,术后定期随访。结果 206例乳腺癌术中成功活检SLN204例,成功率为99.0%(204/206)。本组有64例仅行SLN切除,术后病理检查证实64例SLN均阴性,故未行腋窝淋巴结清除,其中仅1例于术后1年时出现腋窝淋巴结转移,其余63例患者在随访期间均未发现腋窝淋巴结转移,也未出现同侧上肢水肿、感觉及活动异常;另140例行腋窝淋巴结清除,其中6例经病理证实SLN阳性但腋窝淋巴结为阴性,134例经病理证实SLN阳性35例,阴性99例,腋窝淋巴结阳性37例,阴性97例。核素淋巴显像和γ探针定位法的灵敏度为94.6%(35/37例),准确率为98.5%(138/140),假阴性为5.4%(2/37)。结论核素淋巴显像和γ探针定位应用于乳腺癌是切实可行和可能的,对预测腋窝淋巴结转移有很大的临床实用价值。如技术方法规范,早期乳腺癌前哨淋巴结活检则能取代常规的腋窝淋巴结清除术,乳腺癌手术上肢并发症的发生率可大大降低。     

Extra-axillary sentinel node biopsy in the management of early breast cancer.

AIM: To document of our experience with EAS SNB and evaluate its impact on the staging, management and the associated morbidities of patients with early breast cancer. METHOD: A review of two prospective breast cancer databases identifying all SNB procedures performed at two affiliated breast units from 1998 to 2003. RESULTS: A series of 979 patients underwent lymphatic mapping. Sentinel nodes were successfully identified in 903 patients. There were 142 cases in which lymphoscintigraphy identified EAS. In 17 cases extraaxillary sentinel nodes were identified with lymphoscintigraphy but could not be removed. There were 138 cases where internal mammary nodes (IMN) were removed. Of those IMN removed 25 were positive for metastases and in six of these cases only the IMN was positive. Of the 21 cases where other EAS were identified there was one case in which a supraclavicular sentinel node was positive. Twenty-five of the 26 positive sentinel nodes in EAS were macrometastases and one was a micrometastasis. No significant morbidity resulted from biopsy of EAS SNB. During IMN SNB there were eight pleural breeches, which did not result in pneumothoraces, and one case in which bleeding was difficult to control. CONCLUSION: EAS SNB is technically feasible in the majority of cases. Minimal morbidity occurs after an initial learning phase. IMN SNB was shown to have significant impact on the staging and management in 18% of patients when IMNs were identified with lymphoscintigraphy. The impact of other extraaxillary lymph nodes is more difficult to assess due to small numbers. As there is little morbidity and valuable information is gained in a significant percentage of cases we strongly advocate EAS SNB.     

Accuracy of sentinel node biopsy in predicting nodal status in patients with breast carcinoma

BACKGROUND AND OBJECTIVES: While sentinel lymph node biopsy is considered by many to have replaced axillary node dissection in the management of breast cancer, concerns remain regarding false-negative results. METHODS: To investigate the accuracy of sentinel node biopsy, we reexamined all sentinel and nonsentinel nodes with multilevel sectioning and immunohistochemical staining in 42 consecutive cases of breast cancer in which sentinel node biopsy was performed and followed by axillary dissection. RESULTS: By routine hematoxylin and eosin (H&E) staining, 34% of patients were found to be node positive, with no cases of false-negative sentinel node biopsy. Reevaluation of 775 negative sentinel and nonsentinel nodes with an additional two levels and immunohistochemistry identified three "node-negative" patients who had micrometastases in the sentinel node, increasing detection in 8% of cases. More important, is the fact however, that there were no cases where additional sections and immunohistochemistry identified metastases in nonsentinel nodes that had bypassed the sentinel node. The accuracy of the sentinel node in predicting the nodal status was 100%. CONCLUSIONS: Cytokeratin immunohistochemistry will identify more patients with nodal micrometastases; however, it was unable to identify any cases where micrometastases were present in nonsentinel nodes when the sentinel node was negative. The status of the sentinel node accurately identifies the status of the axillary basin.