Clinical relevance of internal mammary node mapping as a guide to radiation therapy.

BACKGROUND: The surgical management of breast cancer has changed markedly with the development of lymphatic mapping and sentinel lymph node (SLN) biopsy. Lymphatic mapping technique varies with respect to injection method, mapping agent, and surgical technique. The decision to pursue the internal mammary nodes (IMN) is another source of controversy. METHODS: From April 1998 to November 2000, 1,470 patients underwent lymphatic mapping for breast cancer and were prospectively entered into the breast database. The combined technique method was used, consisting of both isosulfan blue dye and technetium-99 labeled sulfur colloid. Patients with inner quadrant lesions and suspicion for internal mammary metastasis had preoperative lymphoscintigraphy. Those with internal mammary radioactivity noted by either lymphoscintigraphy or gamma probe underwent removal of the internal mammary sentinel nodes. RESULTS: Thirty-six of the 1,470 (2.4%) patients mapped had at least 1 internal mammary lymph node removed. Inner quadrant lesions were present in 24 of the 36 (67%) IMN mapped patients. Of the 36 patients mapping to the IM area, 5 (14%) had at least 1 IM node positive. Two of the 5 (40%) had only IM metastasis, with 1 of these patients having 5 of 5 IMN positive and no disease detected in her axilla. A total of 2 of the 5 (40%) IM positive patients had more than 1 IMN positive. Twenty-eight of the 36 (78%) IM node harvested patients had preoperative lymphoscintigraphy, with 18 (64%) IMN appearing on imaging. Complications occurred in 3 of the 36 (8%) IMN mapped patients, without clinical significance. CONCLUSIONS: Mapping to the IMN basin with the finding of metastasis results in N3 disease by the current staging system. The consequence for these patients is radiation therapy to the IMN basin. It is significant to note that 14% (5 of 36) were upstaged as result of IMN detection and 40% (2 of 5) had multiple positive IMNs. Substantial disease was detected in these 5 patients necessitating additional radiation therapy while avoiding IM radiation and its attendant complications in 86% of patients mapping to the IM basin.

Importance of lymphatic mapping in ductal carcinoma in situ (DCIS): why map DCIS?

The appropriateness of sentinel lymph node biopsy in the management of patients with biopsy diagnoses of ductal carcinoma in situ (DCIS) or DCIS with microinvasion (DCISM) has not been established. Three hundred forty-one patients presented with a biopsy diagnosis of DCIS or DCISM. Two hundred forty (70%) underwent sentinel node biopsy at their definitive procedure. All clinical and pathologic data were collected prospectively. Of 224 patients with a biopsy diagnosis of DCIS 23 (10%) were upstaged to infiltrating ductal carcinoma (IDC) at their definitive therapy and of 16 patients with a biopsy diagnosis of DCISM seven (44%) were upstaged to IDC. Excisional biopsies were no more sensitive for detecting IDC than was core biopsy. Lymph node metastases were detected in 26 of 195 (13%) patients with a definitive diagnosis of DCIS, in three of 15 (20%) with a definitive diagnosis of DCISM, and in eight of 30 (27%) with a definitive diagnosis of IDC. Sentinel lymph node biopsy is a valuable tool in the treatment of patients with DCIS and DCISM and is particularly needed in those undergoing mastectomy. No "high-risk" group of patients can be identified for selective sentinel lymph node biopsy.

Characteristics of the sentinel lymph node in breast cancer predict further involvement of higher-echelon nodes in the axilla: a study to evaluate the need for complete axillary lymph node dissection.

BACKGROUND: Sentinel lymph node (SLN) biopsy techniques provide accurate nodal staging for breast cancer. In the past, complete lymph node dissection (CLND) (levels 1 and 2) was performed for breast cancer staging, although the therapeutic benefit of this more extensive procedure has remained controversial. HYPOTHESIS: It has been demonstrated that if the axillary SLN has no evidence of micrometastases, the nonsentinel lymph nodes (NSLNs) are unlikely to have metastases. OBJECTIVE: To determine which variables predict the probability of NSLN involvement in patients with primary breast carcinoma and SLN metastases. METHODS: An analysis of 101 women with SLN metastases and subsequent CLND was performed. Variables included size of the primary tumor, tumor volume in the SLN, staining techniques used to initially identify the micrometastases (cytokeratin immunohistochemical vs hematoxylin-eosin), number of SLNs harvested, and number of NSLNs involved with the metastases. Tumor size was determined by the invasive component of the primary tumor. Patients with ductal carcinoma in situ who were upstaged with cytokeratin staining were considered to have stage T1a tumors. RESULTS: Sentinel lymph node micrometastases (<2 mm) detected initially by cytokeratin staining were associated with a 7.6% (2/26) incidence of positive CLND compared with a 25% (5/20) incidence when micrometastases were detected initially by routine hematoxylin-eosin staining. Sentinel lymph node micrometastases, regardless of identification technique, inferred a risk of 15.2% (7/46) for NSLN involvement. As the volume of tumor in the SLN increased (ie, <2 mm, >2 mm, grossly visible tumor), so did the risk of NSLN metastases (P<.001). CONCLUSIONS: Our study demonstrated that patients with micrometastases detected initially by cytokeratin staining had low-volume disease in the SLN with a small chance of having metastases in higher-echelon nodes in the regional basin other than the SLN. Characteristics of the SLN can provide information to determine the need for a complete axillary CLND. Complete lymph node dissection may not be necessary in patients with micrometastases detected initially by cytokeratin staining since the disease is confined to the SLN 92.4% of the time. However, the therapeutic value of CLND in breast cancer remains to be determined by further investigation.

Utility of internal mammary lymph node removal when noted by intraoperative gamma probe detection.

BACKGROUND: Lymphatic mapping (LM) for breast cancer has made internal mammary node (IMN) detection practical and dependable. This study demonstrates the necessity of IMN removal when suggested by intraoperative radioguided surgery detection. METHODS: From April 1998 to July 2000, 1273 patients underwent LM for breast cancer. LM was performed using the combined dye and radiocolloid technique. Patients were scanned operatively with a gamma probe over the IMN area, and most underwent preoperative lymphoscintigraphy. Nodes were removed from patients in whom radioactivity was detected in the internal mammary area. RESULTS: Thirty of the 1273 (2.4%) patients mapped had at least one IMN removed. Twenty-two of 30 (73.3%) had inner quadrant lesions. Five of 30 (16.7%) patients had IMNs that were positive for metastatic disease. Three of these five had no metastatic spread to the axillary sentinel lymph node (SLN). One of thirty (3.3%) patients with IMN localization had neither hot nor blue nodes detected in an SLN procedure. CONCLUSIONS: Radioguided SLN detection should be attempted in the IMN basin with all tumors. If an IMN is identified, it should be removed. IMN biopsy is a feasible, low-risk procedure when directed by radioguided LM and provides a guide for radiotherapy for patients with positive IMNs.

Do cytokeratin-positive-only sentinel lymph nodes warrant complete axillary lymph node dissection in patients with invasive breast cancer?

The small number of nodes harvested with lymphatic mapping and sentinel lymph node (SLN) biopsy has allowed a more detailed pathologic examination of those nodes. Immunohistochemical stains for cytokeratin (CK-IHC) have been used in an attempt to minimize the false negative rate for SLN mapping. This study examines the value of CK-IHC positivity in predicting further lymph node involvement in the axillary basin. From April 1998 through May 1999, 519 lymphatic mappings and SLN biopsies were performed for invasive breast cancer. SLNs were examined by imprint cytology, hematoxylin and eosin (H&E), and CK-IHC. Patients with evidence of metastatic disease by any of the above techniques were eligible for complete axillary node dissection (CAND). The frequency with which these modalities predicted further lymph node involvement in the axillary basin was compared. Of the 519 lymphatic mappings, 39 patients (7.5%) had a CK-IHC-positive-only SLN. Five (12.8%) of these 39 patients had at least 2 SLNs positive by CK-IHC. Twenty-six of the CK-IHC-positive-only patients underwent CAND. Three of these 26 patients (11.5%) had additional metastases identified after CAND. The sensitivity levels with which each modality detected further axillary lymph node involvement were as follows: CK-IHC, 98 per cent; H&E, 94 per cent; and imprint cytology, 87 per cent. A logistic regression to compare the prognostic value of the three modalities was performed. All were significant, with odds ratios of 19.1 for CK-IHC (P = 0.015), 5.3 for H&E (P = 0.033), and 3.86 for imprint cytology (P = 0.0059). These data validate the enhanced detection of CK-IHC for the evaluation of SLNs. Detection of CK-IHC-positive SLNs appears to warrant CAND in patients with invasive breast cancer. However, the therapeutic value of CAND or adjuvant therapies based on CK-IHC-positive SLNs would be best answered by prospective randomized trials.

Lymphatic mapping and sentinel lymph node biopsy in patients with breast cancer.

The standard of care for the evaluation of axillary nodal involvement remains complete lymph node dissection. Lymphatic mapping and sentinel lymph node (SLN) biopsy are changing this long-held paradigm; indeed, several leading institutions already reserve complete axillary dissection for patients with metastasis to the SLN. In addition to reviewing the literature, this chapter describes our lymphatic mapping experience at the H Lee Moffitt Cancer Center and Research Institute with 1147 breast cancer patients. Our results, in addition to a meta-analysis of data from 12 institutions comprising an additional 1842 patients undergoing complete axillary dissection, demonstrate that SLN biopsy is an accurate method of axillary staging. Although the results from small series may exaggerate the probability of false negative results, the risk of nodal disease based on tumor size and other risk factors should be evaluated when considering the results of SLN sampling.

Lymphatic mapping with sentinel lymph node biopsy in patients with breast cancers <1 centimeter (T1A-T1B).

Because of its high cost and attendant morbidity, the necessity of axillary dissection in patients with small invasive primary tumors has been questioned. Lymphatic mapping with sentinel lymph node (SLN) biopsy is an alternative to complete axillary dissection; however, researchers have excluded patients with T1A-T1B lesions. Seven hundred patients with newly diagnosed breast cancers underwent an Institutional Review Board-approved prospective trial of intraoperative lymphatic mapping using a combination of Lymphazurin and filtered technetium-labeled sulfur colloid. An SLN was defined as a blue node and/or hot node with a 10:1 ex vivo radioactivity ratio in the SLN versus non-SLNs. All SLNs were evaluated by both hematoxylin and eosin and cytokeratin immunohistochemical stains. Of the 700 patients, 665 (95.0%) were mapped successfully. One hundred ninety-six (28.0%) had T1A-T1B tumors. Forty patients (20.4%) with T1A-T1B tumors had metastases to the SLNs. We conclude that breast cancer SLN mapping is highly accurate and sensitive when combined dye techniques (radiocolloid and vital blue dye) are utilized. This technique is particularly useful in patients with small invasive primary tumors, which, despite their size, still demonstrate a significant rate of axillary metastasis. These patients should not be excluded from lymphatic mapping protocols.

The role of sentinel lymph node biopsy in breast cancer.

BACKGROUND: Lymphatic mapping and sentinel lymph node (SLN) biopsy are new techniques that accurately provide crucial staging information while inflicting far less morbidity than complete axillary dissection. As these techniques continue to gain acceptance, issues such as adequacy of training, certification, and outcomes measures become increasingly important. The purpose of this paper is to report the initial lymphatic mapping experience at the H Lee Moffitt Cancer Center and Research Institute and to provide a detailed description of the technical aspects of lymphatic mapping. STUDY DESIGN: From April 1994 to April 1998, 700 patients with newly diagnosed breast cancers underwent an IRB-approved prospective trial of lymphatic mapping using a combination of Lymphazurin (USSC, Norwalk, CT) blue dye and filtered technetium 99m-labeled sulfur-colloid. Failure of the procedure was defined as the inability to detect an SLN by either radiocolloid uptake within a lymph node by the gamma probe or the inability to visualize blue staining of a lymph node. Learning curves were then generated as the failure rate versus serial number of patients for each of the 5 surgeons involved in this study. RESULTS: The SLN was identified in 665 of 700 patients (95.0%). A total of 1,348 SLNs were successfully removed, of which 238 (17.7%) were positive for metastatic disease in 176 of 665 patients (26.5%). In patients who underwent a complete axillary dissection after SLN biopsy, SLNs were identified in 173 of 186 patients (93.0%). Of the 173 patients, 53 patients (30.6%) had positive SLNs and 120 patients (69.4%) had negative SLNs. In the 120 patients with negative SLNs, one patient was found to have disease on complete dissection, for a false-negative rate of 0.83% (95% CI: 0.02%, 4.6%). A learning curve representing the mean of the 5 surgeons' experience indicates that on average 23 patients are required by an individual surgeon to achieve a 90% +/- 4.5% success rate and 53 patients are required to achieve a 95% +/- 2.3% success rate (p = 0.05). CONCLUSIONS: These data validate lymphatic mapping and SLN biopsy as indispensable tools in the surgical treatment of breast cancer. With adequate multidisciplinary training, these techniques can be readily implemented at institutions treating breast cancer.

Pathologic examination of sentinel lymph nodes in breast cancer.

Lymphatic mapping with selective sentinel lymphadenectomy allows accurate pathologic examination of the nodes most likely to contain macro- or micrometastastic disease for staging and proper adjuvant chemotherapy. The hypothesis of SLN biopsies was histopathologically validated by Turner et al that if the node is tumor free by H&E and immunohistochemistry, the probability of non-SLN involvement is less than 0.1%. Giuliano et al and Veronesi et al reported that detection of metastases in SLNs by frozen section technique is 89% and 64%, respectively. At MCC, frozen section evaluation of SLN is not performed because of its potential loss of micrometastasis in the cryostat, freezing artifacts, sampling error, and perhaps radioactive contamination. Intraoperative detection of macro- or micrometastasis is critical because it enables conversion of patients with positive SLN to CLND in one surgical setting more cost-effectively. IIC of the lymph nodes has been used routinely in the diagnosis of hematologic malignancies and also in breast cancer as a useful method in many series. In the author's experience, IIC by Diff-Quik stain converted 100% of grossly positive and suspicious SLNs and 22% of grossly negative SLNs. The significance of detecting micrometastases in axillary lymph nodes using immunohistochemical techniques has been reported in many series. At the MCC, routine use of CKI on paraffin sections of grossly negative SLNs enabled the upstaging of 10.6% of patients from N0 to N1. Recent addition of intraoperative rapid CKI as an adjunct to complement Diff-Quik stain has proven to be more sensitive in detecting micrometastases than using Diff-Quik stain alone. IIC technique using either Diff-Quik stain or CKI requires intensive training and experience to avoid potential pitfalls and errors in interpretation. Evaluation of SLN should use methods that enhance the ability to detect micrometastasis, however, in a cost-effective manner. The cost-effectiveness of IIC by Diff-Quik stain is incomparable with frozen section evaluation. The added cost of routine immunohistochemical stain and perhaps multiple levels of H&E stain should be offset by the decreased costs of IIC and clinically by treating most patients in the outpatient settings. In summary, IIC by Diff-Quik stain is simple, rapid, and has excellent diagnostic accuracy in grossly positive and suspicious SLNs allowing cost-effective, immediate CLND. IIC by CKI is an extremely useful ancillary technique that complements Diff-Quik stain in detecting micrometastases particularly in low grade ductal or lobular carcinoma and low tumor cell volume. Appropriate combined use of both stains may lead to intraoperative nodal staging and cost-effective CLND. SLN mapping technology at MCC using IIC in conjunction with serial sections, entire tissue submission, routine use of CKI, and multiple levels of the SLN have led us to uncover micrometastasis in high-risk, traditionally node-negative patients. These results have encouraged investigators to pursue even more sensitive techniques to detect micrometastases, including molecular biology techniques such as RT-PCR. Experienced cytopathologists and active cytopathology services are required to avoid potential pitfalls in performing and interpreting IIC. More long-term follow-up and prospective trials are needed to determine the prognostic significance of upstaging by ancillary techniques, which may lead to a revision of the current TNM staging system.

Sentinel node biopsy and cytokeratin staining for the accurate staging of 478 breast cancer patients.

Sentinel lymph node (SLN) mapping is an effective and accurate method of sampling the axillary nodal basin for metastatic disease. The SLN is the first node to receive afferent lymphatic drainage from the primary tumor. Lymphatic mapping and SLN biopsy have allowed pathologists to perform a more detailed examination of the SLN(s) and, therefore, provide more accurate staging of the regional lymphatic basin. Recently, more sensitive assays have been developed to increase the detection rate of micrometastatic to the axillary lymph nodes. Cytokeratin (CK) immunohistochemical (IHC) staining of the SLN detects micrometastatic disease, which is frequently missed on routine hematoxylin and eosin (H&E) histology. Therefore, lymphatic mapping combined with CK IHC staining of the SLN provides more accurate staging of the regional lymph nodes in patients with breast cancer. At Moffitt Cancer Center, 478 patients with newly diagnosed breast cancer underwent intraoperative lymphatic mapping using a combination of vital blue dye and technetium-labeled sulfur colloid. The excised SLNs were examined grossly, by intraoperative imprint cytology, by standard H&E histology, and by IHC stains for CK. SLNs that were only CK positive were confirmed malignant by sectioning the block, staining with H&E and finding cells with malignant cytology. Lymphatic mapping and CK IHC staining of the SLNs was successfully performed in 478 newly diagnosed breast cancer patients. Twenty-eight patients had unsuccessful lymphatic mapping for an overall failure rate of 5.5 per cent. A total of 134 (28%) patients had positive nodes (N1) detected. Ninety-three of these patients had both H&E and CK-positive lymph nodes, and an additional 41 patients had only CK-positive SLN(s). A total of 385 patients had H&E-negative SLNs, but only 344 patients had negative SLN(s) defined as both H&E and CK negative. Therefore, 41 (10.6%) of the 385 H&E-negative patients were upstaged, because of the detection of malignant cells by cytokeratin IHC staining of the SLN. Microstaging of SLNs with CK has shifted 10.6 per cent of our patient population from stage I to stage II disease. Undetected micrometastatic disease to the regional lymph nodes may account for the significant proportion of stage I breast cancer treatment failures. Furthermore, the ability to accurately stage the axilla by using lymphatic mapping techniques, SLN biopsy, and more sensitive assays may help identify a subgroup of truly node-negative patients with invasive breast cancer who can avoid the morbidity associated with a complete axillary dissection or systemic chemotherapy. Finally, those patients found to have micrometastatic disease to the regional lymph nodes can be treated appropriately in a more selective fashion.

Lymphatic mapping in breast cancer.

The most accurate predictor of survival in breast cancer is the presence or absence of lymph node metastases. Lymphatic mapping with sentinel node biopsy is a new technique that provides more accurate nodal staging compared with routine histology for women with breast cancer, but without the morbidity of a complete lymph node dissection. Sentinel lymph node (SLN) biopsy is a more conservative approach to the axilla that requires close collaboration from the surgical team, nuclear medicine, and pathology. National trials are investigating the clinical relevance of the upstaging that occurs with a more intense examination of the SLN. As is the case with breast preservation as a viable alternative to mastectomy for the definitive treatment of the primary node, selective lymphadenectomy has the ability to decrease morbidity without compromising patient care.

Microstaging of breast cancer patients using cytokeratin staining of the sentinel lymph node.

BACKGROUND: Sentinel lymph node (SLN) mapping is an effective and accurate method of axillary nodal evaluation for metastatic disease. Cytokeratin (CK) immunohistochemical (IHC) staining of the SLN has found micrometastatic disease previously undetected by routine hematoxylin and eosin (H&E) stains. The purpose of this study is to determine the number of patients who were upstaged or microstaged, i.e., detected to have micrometastatic disease only by combined lymphatic mapping with CK IHC. METHODS: Two hundred and ten patients with newly diagnosed breast cancer underwent intraoperative lymphatic mapping using a combination of vital blue dye and technetium-labeled sulfur colloid. The excised sentinel lymph nodes were examined grossly, by imprint cytology, by standard H&E histology, and by IHC stains for CK. SLNs that were only CK positive were confirmed to be malignant by histologic examination. RESULTS: CK IHC staining was performed on 381 SLNs in 210 breast cancer patients. Forty-seven of 210 patients (22.4%) had positive nodes. Thirty of these 47 patients (63.8%) had both H&E- and CK-positive SLNs, and an additional 17 of the 47 positive patients (36.2%) had only CK-positive SLNs. Seventeen of the 180 patients (9.4%) who were negative on H&E staining were upstaged by CK IHC staining of malignant cells in the SLN. Comparison of tumor size with the total number of node-positive patients demonstrated that 16 of 30 node-positive T0 and T1 patients (53.5%) and 22 of 39 nodes (56.4%) were upstaged by CK IHC staining. T2 and T3 patients were less frequently upstaged by cytokeratin analysis of lymph nodes. Only one of 17 node-positive patients (5.9%) and seven of 34 nodes (20.6%) in patients with T2 and T3 tumors were upstaged. CONCLUSION: CK IHC staining of SLNs shifted 9.4% of patients from stage I to stage II. There was a significant upstaging influence noted in patients with tumor sizes under 2 cm. This microstaging shift or upstaging may account for the significant proportion of stage I breast cancer treatment failures. Microstaging of the SLNs using more sensitive assays may help identify a subgroup of patients with invasive breast cancer who would benefit from systemic adjuvant treatment, while sparing a disease-free subset of patients the additional risks of toxic adjuvant chemotherapy.

Automated Papanicolaou smear analysis as a screening tool for female lower genital tract malignancies.

The cervical Papanicolaou (Pap) smear is the most effective and inexpensive cancer screening test in medical history for the identification of premalignant cervicovaginal lesions. Despite this fact, false-negative rates ranging from 6% to 55% have been sporadically reported, resulting in an increase in litigation. With the development of computer-based automated technology, a significant proportion of such false-negative results have been reduced by rescreening of negative smears. This article reviews the automated technology approved by the USA Food and Drug Administration and its use, including performance, accuracy and cost-effectiveness compared with the results of conventional manual screening.

Lymphatic mapping in the treatment of breast cancer.

Developed initially for the treatment of malignant melanoma, lymphatic mapping and sentinel lymph node biopsy have recently been introduced into the treatment of early breast cancer. In breast cancer patients, harvested sentinel lymph nodes are evaluated more thoroughly by detailed pathologic examination using serial sectioning, immunohistochemistry, and reverse transcriptase-polymerase chain reaction (RT-PCR) techniques. This allows for the detection of smaller tumor volumes and leads to more accurate staging. Lymphatic mapping has a 68% to 98% success rate in identifying the sentinel lymph node. The false-negative rate (defined as a negative sentinel lymph node while a higher node or nodes in the axilla are positive) is between 0% and 2%. The morbidity associated with this procedure is minimal. We believe that lymphatic mapping and sentinel lymph node biopsy will ultimately lead to more conservative treatment of patients with breast cancer. This article describes the historical background and technical aspects of the procedure. This is followed by updated, prospectively collected outcomes data from 466 consecutive breast cancer patients who underwent lymphatic mapping at the H. Lee Moffitt Cancer Center, as well as an up-to-date review of the literature.

Local recurrence of breast cancer after cytological evaluation of lumpectomy margins.

Successful breast conservation therapy with optimal cosmesis requires adequate tumor excision and negative tumor margins. Therefore, more sensitive techniques are being developed to identify lumpectomy margins intraoperatively with greater accuracy. Unidentified microscopic disease is seemingly responsible for a local recurrence rate of up to 25 per cent 3 to 5 years after lumpectomy and radiotherapy for breast cancer patients. As a result, Moffitt Cancer Center has routinely used an intraoperative touch preparation cytology (TPC) protocol to evaluate the entire resected surface of all lumpectomies. In addition, resection margins were also evaluated by gross examination and by standard histology. In rare instances frozen sections were used to evaluate tumor margins. In this study 701 consecutive lumpectomy specimens were evaluated by TPC during the period of 9 years with a mean follow-up of 3.5 years. Local cancer recurrence was 2.7 per cent (mean recurrence, 2.53 years), in women whose lumpectomy margins were evaluated by TPC. Of interest, a local recurrence rate of 14.6 per cent was observed in patients who had referral lumpectomies evaluated by conventional histopathology. This study suggests that accurate margin assessment with TPC plays an important role in the control of local recurrence after breast conservation therapy. Therefore, we conclude the routine use of intraoperative TPC provides rapid, reliable, topographically accurate identification of residual microscopic disease at lumpectomy margins.

Guidelines for sentinel node biopsy and lymphatic mapping of patients with breast cancer.

OBJECTIVE: To define preliminary guidelines for the use of lymphatic mapping techniques in patients with breast cancer. SUMMARY BACKGROUND DATA: Lymphatic mapping techniques have the potential of changing the standard of surgical care of patients with breast cancer. METHODS: Four hundred sixty-six consecutive patients with newly diagnosed breast cancer underwent a prospective trial of intraoperative lymphatic mapping using a combination of vital blue dye and filtered technetium-labeled sulfur colloid. A sentinel lymph node (SLN) was defined as a blue node and/or a hot node with a 10:1 ex vivo gamma probe ratio of SLN to non-SLN. All SLNs were bivalved, step-sectioned, and examined with routine hematoxylin and eosin (H&E) stains and immunohistochemical stains for cytokeratin. A cytokeratin-positive SLN was defined as any SLN with a defined cluster of positive-staining cells that could be confirmed histologically on H&E sections. RESULTS: Fine-needle aspiration (FNA) or stereotactic core biopsy was used to diagnose 195 of the 422 patients (46.2%) with breast cancer; 227 of 422 patients (53.8%) were diagnosed by excisional biopsy. The SLN was successfully identified in 440 of 466 patients (94.4%). Failure to identify an SLN to the axilla intraoperatively occurred in 26 of 466 patients (5.6%). In all patients who failed lymphatic mappings, a complete axillary dissection was performed, and metastatic disease was documented in 4 of 26 (15.4%) of these patients. Of the 26 patients who failed lymphatic mapping, 11 of 227 (4.8%) were diagnosed by excisional biopsy and 15 of 195 (7.7%) were diagnosed by FNA or stereotactic core biopsy. Of interest, there was only one skip metastasis (defined as a negative SLN with higher nodes in the chain being positive) in a patient with prior excisional biopsy. A mean of 1.92 SLNs were harvested per patient. Twenty percent of the SLNs removed were positive for metastatic disease in 105 of 440 (23.8%) of the patients. Descriptive information on 844 SLNs was evaluated: 339 of 844 (40.2%) were hot, 272 of 844 (32.2%) were blue, and 233 of 844 (27.6%) were both hot and blue. At least one positive SLN was found in 4 of 87 patients (4.6%) with noninvasive (ductal carcinoma in situ) tumors. A greater incidence of positive SLNs was found in patients who had invasive tumors of increasing size: 18 of 112 patients (16%) with tumor size between 0.1 mm and 1 cm had positive SLNs. However, a significantly greater percentage of patients (43 of 131 [32.8%] with tumor size between 1 and 2 cm and 31 of 76 [40.8%] with tumor size between 2 and 5 cm) had positive SLNs. The highest incidence of positive SLNs was seen with patients of tumor size greater than 5 cm; in this group, 9 of 12 (75%) had a positive SLN (p < 0.001). CONCLUSIONS: This study demonstrates that accurate SLN identification was obtained when all blue and hot lymph nodes were harvested as SLNs. Therefore, lymphatic mapping and SLN biopsy is most effective when a combination of vital blue dye and radiolabeled sulfur colloid is used. Furthermore, these data demonstrate that patients with ductal carcinoma in situ or small tumors exhibit a low but significant incidence of metastatic disease to the axillary lymph nodes and may benefit most from selective lymphadenectomy, avoiding the unnecessary complications of a complete axillary lymph node dissection.

Sentinel lymphadenectomy: a safe answer to less axillary surgery?

UNLABELLED: Lymphatic mapping techniques have the potential of changing the standard of surgical care of breast cancer patients. This paper reports a prospective study documenting the safety and efficacy of sentinel lymph node biopsy in 167 breast cancer patients and reviews the world literature on the procedure. METHODS: One hundred sixty-seven patients with newly diagnosed breast cancers underwent a prospective trial of intra-operative lymphatic mapping using a combination of vital blue dye and filtered technetium-labeled sulfur colloid. A sentinel lymph node (SLN) was defined as a blue node and/or "hot" node with a 10/1 ex-vivo gamma-probe ratio of SLN to non-SLN. All SLN were bi-valved, step-sectioned, and examined with routine H&E stains and immunohistochemical stains for cytokeratin. Cytokeratin-positive SLN were defined as any SLN with a defined cluster of positive staining cells which could be confirmed histologically on H&E sections. Finally, a review of the worldwide data was undertaken using a uniform analytical method to compare the rates of sensitivity, diagnostic accuracy, and false negatives of SLN mapping. RESULTS: In 167 patients, 337 SLN were harvested, for an average of 2.01 SLN/patient. Fifty-two (31.1%) of the patients had metastasis in the SLN. In the 115 patients with negative SLN, 1 was found to have tumor in higher axillary nodes, for a false negative rate of 0.88%. Fifty-nine (37.8%) of the patients were diagnosed by fine-needle aspiration, 89 (53.3%) by excisional biopsy, and 19 (11.4%) by core biopsy. Positive SLN were identified in 1/17 (5.9%) patients with DCIS. Metastasis was found in 33/115 (28.7%) of the patients with infiltrating ductal tumors and in 11/19 (57.9%) of the patients with infiltrating lobular tumors. Positive SLN were identified in 7/16 (43.7%) of the patients with mixed cellularity tumors. Metastasis in the SLN was detected in 7/55 (12.7%) of the 59 patients with T1a-T1b tumors and in 21/58 (36.2%) of the patients with T1c tumors. Positive SLN were found in 17/30 (56.7%) of the patients with T2 tumors and in 6/7 (85.7%) of the patients with T3 tumors. A literature review of 731 patients (including this study) demonstrates a sensitivity rate of 95% and a diagnostic accuracy rate of 98%. The overall false negative rate is 3.1%. CONCLUSIONS: This study demonstrates that SLN biopsy is a highly sensitive and accurate method of predicting axillary nodal status. It is a reproducible technique that is easily learned. The future addition of more sensitive methods such as PCR evaluation of nodal involvement may reduce the need for widespread use of adjuvant chemotherapy with its high cost and attendant morbidity and mortality. We believe that this technique will eventually become the standard of care in the treatment of breast cancer, particularly for T1 and T2 lesions and perhaps also for high-grade DCIS tumors.