Historical perspective of lymphatic tumour spread and the emergence of the sentinel node concept

Sentinel lymph node mapping: current applications and future perspectives in thyroid carcinoma

Sentinel lymph node (SLN) mapping is a standard, minimally-invasive diagnostic method in the surgical treatment of many solid tumors, as for example melanoma and breast cancer, for detecting the presence of regional nodal metastases. A negative SLN accurately indicates the absence of metastases in the other regional lymph nodes (LN), thus avoiding unnecessary lymph nodal dissection. Papillary thyroid carcinoma (PTC) is the most common type of thyroid carcinoma (TC) with cervical LN metastases at diagnosis in 20-90%, and nodal involvement correlates with local persistence/recurrence. The SLN in PTC is an intraoperative method for staging preoperative N0 patients and for detecting metastatic LNs "in and outside" the cervical LN central compartment; it represents an alternative method to prophylactic central neck node dissection. In this review we summarize different methods and results of the use of SLN in TC. The SLN identification techniques currently used include the selective vital-dye (VD) method, 99mTc-nanocolloid planar lymphoscintigraphy with intraoperative use of a hand-held gamma probe (LS), the combination LS + VD, and the combination LS and preoperative SPECT-CT (LS + SPECT/CT). The application of the SLN procedure in TC has been described in many studies, however, the techniques are heterogeneous, and the role of SLN in TC, with indications, results, advantages and limits, is still debated.

Sentinel Lymph Node Mapping and Biopsy for Breast Cancer: A Review of the Literature Relative to 4791 Procedures

The status of axillary nodes is the most important prognostic factor in breast cancer to select patient subgroups for adjuvant chemotherapy; the current standard of care for surgical management of invasive breast cancer is complete removal of the tumor by either mastectomy or lumpectomy followed by axillary lymph node dissection (ALND). The recent introduction of intraoperative lymphatic mapping and sentinel lymph node biopsy (SLND) represents a major new opportunity for appropriate and less invasive surgical management of many tumors. There is an almost uniformly enthusiasm concerning the potential of this technique in breast carcinoma management, shown by published data. A peculiar attention to the so-called “sentinel node debate” in breast cancer surgery is a constant in the last years issues of the major medical journals. Even patients have become more aware about medical enthusiasm and their request of concise information on the topic and the possibilities of this approach is an increasing reality in medical practice.

The aim of this paper is to review recent literature to offer an overview about the main controversial methodological aspects and a wide analysis of reported results. The most significative international literature papers from Medline were retrieved from 1993 to September 1999, and 4782 procedures were analysed. This extensive review of the literature has confirmed accuracy, feasibility and reliability of the SN detecting technique in axillary mapping. Provided a good proficiency in SN localisation and pathological evaluation, human resources and efforts should be mainly focused on its clinical validation as an alternative to ALND instead of on further phase I–-II clinical studies.

Paradigm Shift of Staging and Treatment for Early Breast Cancer in the Sentinel Lymph Node Era

Lymph node status is the most reliable prognostic indicator for the clinical outcome of patients with most solid cancers. Because it is the first node draining the primary cancer, the sentinel lymph node (SLN) is most likely to harbor metastatic cancer cells. The tumor size of primary breast cancer is highly correlated with SLN metastasis. If the SLN is negative, the negative predictive value of the remaining nodal basin exceeds 95%. It appears that even using different techniques from different institutions, the successful rate to harvest the SLN is more than 95%. The false-negative rate is about 5-10% in most series. Breast cancer patients with early detection and a negative SLN have a significantly improved survival rate. The SLN data in breast cancer is so convincing that SLN information has been incorporated into the new American Joint Committee on Cancer (AJCC) classification of breast cancer. The therapeutic value of additional lymph node dissection after a positive SLN for breast cancer is still controversial. Follow-up data from breast cancer patients is somewhat limited, but available information shows that patients with negative SLNs fare much better. In summary, several important patterns of metastasis can be established based on the current SLN experience: 1) The earlier the breast cancer is found, the less the metastatic potential. 2) In most cases, breast cancer follows an orderly progression of metastasis to the SLN. 3) A small subgroup of patients may develop systemic dissemination without SLN involvement. Since metastatic cancer is usually incurable, it is important for oncologists to detect and resect an early breast cancer without delay. The challenge in the future will be to dissect these different patterns of metastasis based on molecular or genetic markers. Such information will be critical to select high-risk patients for adjuvant therapy.

Sentinel Lymph Node Tumor Load: An Independent Predictor of Additional Lymph Node Involvement and Survival in Melanoma

BACKGROUND

Even though 60% to 80% of melanoma patients with a positive sentinel lymph node (SLN) have no positive additional lymph nodes (ALNs), all these patients are subjected to an ALN dissection (ALND) with its associated morbidity. The aim of this study was to predict the absence of ALN metastases in patients with a positive SLN by using features of the primary melanoma and SLN tumor load.

METHODS

Of 71 SLN-positive patients, 52 had metastasis limited to the SLN (group 1), and 19 had > or =1 positive ALN after ALND (group 2). The tumor load of the SLN was assessed by measuring the total surface area by computerized morphometry. Breslow thickness, ulceration and lymphatic invasion of the primary tumor, and total SLN metastatic area were tested as covariates predicting the absence of positive ALNs.

RESULTS

The mean SLN metastatic area was 1.18 mm(2) (group 1) and 3.39 mm(2) (group 2) (P = .003) and was the only significant and independent factor after multivariate analysis (P = .02). None of the patients with both a Breslow thickness <2.5 mm and an SLN metastatic area <.3 mm(2) had a positive ALN.

CONCLUSIONS

SLN metastatic area can be used to predict the absence of positive ALNs in melanoma patients. In this study, patients with a Breslow thickness <2.5 mm and an SLN tumor load <.3 mm(2 )seemed to have no positive ALN and had excellent survival. We hypothesize that this subgroup might not benefit from ALND. Prospective larger trials, using this model and randomizing between ALND and no ALND, should confirm this hypothesis.

Selective sentinel lymphadenectomy for malignant melanoma, Merkel cell carcinoma, and squamous cell carcinoma

To date, selective sentinel lymphadenectomy (SSL) should be considered a standard approach for staging patients with primary invasive melanoma greater than or equal to 1 mm. It is imperative that the multidisciplinary team master the techniques of preoperative lymphoscintigraphy, intraoperative lymphatic mapping, and postoperative pathologic evaluation of the sentinel lymph nodes (SLNs). An SLN is defined as a blue, "hot" and any subsequent lymph node greater than 10% of the ex vivo count of the hottest lymph node. Any enlarged or indurated lymph node in the nodal basin should be excised. Frozen sections are not recommended. For extremity melanoma, delayed SSL may be performed. Preoperative lymphoscintigraphy for extremity melanoma may be done the night before so that the surgery can be scheduled as the first case of the following day. Every surgeon who uses blue dye should be aware of the potential adverse reaction to isosulfan blue and treatment for such a potential fatal reaction. A complete lymph node dissection is done if the SLN is found to be positive. Elective lymph node dissection (ELND) should not be done if an SSL can be performed as a staging procedure. SSL has further been applied to stage the nodal basin for Merkel cell carcinoma and high-risk squamous cell carcinoma. It is important for investigators involved with the SSL to follow the clinical outcome of these patients, so that the role of SSL can be further defined.

Evaluation of extensive initial staging procedure in intermediate/high-risk melanoma patients

INTRODUCTION

Early diagnosis and treatment of metastases have been shown to improve overall survival of melanoma patients. The purpose of this study was to evaluate the impact of extensive initial staging, including positron emission tomography (PET) scan on the management of melanoma patients.

PATIENTS AND METHODS

Forty-three patients with intermediate/poor prognosis primary melanoma benefited from complementary excision and sentinel lymph node biopsy (SLB) after clinical and paraclinical staging (computed tomography, nuclear magnetic resonance and whole body fluorodeoxyglucose PET scan).

RESULTS

No systemic metastases were demonstrated, while the SLB procedure emphasized the presence of regional lymph node metastases in 10 patients as suggested by the PET scan in four patients (sensitivity of the PET scan 40%). These 10 patients with early diagnosed lymph node involvement benefited from early surgery and were included in adjuvant treatment protocols. A secondary primary cancer was fortuitously diagnosed and treated early in two patients.

CONCLUSIONS

The development of new adjuvant therapies and therapeutic procedures (specific and non-specific immunotherapy, gamma-knife radiosurgery, etc.) now raises the relevance of extensive staging in intermediate/poor prognosis melanoma patients. We confirm in our series that PET scan is not useful to detect micrometastasis and cannot replace SLB in initial regional staging. However, we show in our study that 12 of 43 patients were treated early or were included early in treatment protocols thanks to the extensive staging procedure. Nevertheless, it seems important to evaluate through larger prospective trials the real impact of these early diagnoses and new treatments on overall survival before defining new diagnostic and therapeutic guidelines.

Paradigm of metastasis for melanoma and breast cancer based on the sentinel lymph node experience

Lymph node status is the most reliable prognostic indicator for patients with melanoma and breast cancer. Because it is the first node draining the primary cancer, the sentinel lymph node (SLN) is most likely to harbor metastatic cancer cells. The Breslow thickness of the primary melanoma and the size of primary breast cancer are highly correlated with SLN metastasis. If the SLN is negative, its negative predictive value for the remaining nodal basin exceeds 95%; thus, survival rates for melanoma and breast cancer increase when the SLN is negative. The rate of SLN identification is more than 95%, and the false-negative rate is about 5%. SLN data from melanoma and breast cancer are so convincing that they have been incorporated into the new American Joint Committee on Cancer classification of these cancers. The therapeutic value of additional lymph node dissection after a positive SLN for melanoma or breast cancer is still controversial. In melanoma, a 3-year follow-up may confirm better survival when the SLN is negative. However, about 25% of histologically negative SLNs may be upstaged by molecular techniques, and patients whose SLNs are positive by polymerase chain reaction (PCR) assay may develop recurrence. In most cases, melanoma and breast cancer follow an orderly progression of metastasis to the SLN; however, a small subgroup may develop systemic dissemination without SLN involvement. Current SLN experience has confirmed that the earlier the cancer, the less its potential for metastasis. Since treatments for metastatic cancer are still limited, early detection and resection are imperative. Better understanding of the molecular and genetic mechanisms of metastasis will be critical to select high-risk patients for adjuvant therapy.

Radioguided sentinel lymph node biopsy in patients with malignant cutaneous melanoma: the nuclear medicine contribution

As for other solid tumors, malignant cutaneous melanoma drains in a logical way through the lymphatic system, from the first to subsequent levels. Therefore, the first lymph node encountered (the sentinel node) will most likely be the first to be affected by metastasis, and a negative sentinel node makes it highly unlikely that other nodes in the same lymphatic basin are affected. Sentinel lymph node biopsy distinguishes patients without nodal metastases, who can avoid nodal basin dissection with its associated risk of lymphedema, and those with metastatic involvement who might benefit from additional therapy. This procedure represents a significant advantage as a minimally invasive procedure, considering that only an average 20% of melanoma patients with Breslow thickness between 1.5 and 4 mm harbour metastasis in their sentinel node(s) and are therefore candidates to elective lymph node dissection procedures. The cells that originate cutaneous melanomas are located between dermis and epidermis, a zone that drains to the inner lymphatic network in the reticular dermis, in turn to larger collecting lymphatics in subcutis. Therefore, the optimal modality of interstitial administration of radiocolloids for lymphoscintigraphy and subsequent radioguided sentinel lymph node biopsy is through intradermal/subdermal injection. (99m)Tc-labeled colloids in various size ranges are equally adequate for radioguided sentinel lymph node biopsy in patients with cutaneous melanoma, depending on local experience and availability. For melanomas located in the midline area of the head, neck, and trunk, particular consideration should be given to ambiguous lymphatic drainage, which frequently requires interstitial administration virtually all around the tumor or surgical scar from prior excision of the melanoma. Lymphoscintigraphy is an essential part of radioguided sentinel lymph node biopsy because images are used to direct the surgeon to the sites of the node(s). The sentinel lymph node should have a significantly higher count than that of background (at least 10:1 intraoperatively). After removal of the sentinel node, the surgical bed must be reexamined to ensure that all radioactive sites are identified and removed for analysis. The success rate of radioguidance in localizing the sentinel lymph node in melanoma patients is about 98% in institutions where a high number of procedures are performed, approaching 99% when combined with the vital blue dye technique. The procedure is becoming the standard of care for patients with cutaneous melanoma because of its high prognostic value that has led to include the procedure in the most recent version of the TNM staging system.

Coexistence of micrometastatic melanoma cells and sarcoid granulomas in all regional lymph nodes in a patient with acral melanoma

A 68-year-old woman who had been diagnosed with sarcoidosis presented with acral lentiginous melanoma (Breslow's tumour thickness, 2.6 mm; Clark's level IV) on her right heel. She underwent surgery for excision of the primary tumour and sentinel lymph node biopsy. The two sentinel lymph nodes revealed numerous sarcoidal granulomas and small nests of metastatic melanoma cells in the subcapuslar lesions. She subsequently underwent ilio-inguinal lymph node dissection. Surprisingly, all of the nine dissected nodes were mostly replaced by sarcoidal granulomas and contained melanoma micrometastases.

Superficial femoral lymph node dissection after positive sentinel lymphadenectomy for early-stage melanoma of the lower extremity

The purpose of this study was to evaluate retrospectively the value of a subsequent superficial femoral lymph node dissection for patients with early melanoma of the lower extremity after a positive sentinel lymphadenectomy. During a 6-year period at the H. Lee Moffitt Cancer Center & Research Institute, 16 consecutive patients with clinical stage I or stage II melanoma of the lower extremity underwent subsequent superficial femoral lymph node dissections after positive sentinel lymphadenectomies and wide local excisions of the primary lesions. Fifteen patients (94%) were found to have no additional positive lymph nodes from their superficial femoral lymph node dissection specimens. In contrast, only 1 patient (6%) with a thick primary lesion (7.5 mm) was found to have one additional positive lymph node on a subsequent superficial femoral lymph node dissection. No patients developed any regional nodal recurrences during a mean follow-up of 31.1 months (range, 3-80 months). This preliminary report suggests that the majority of the time the sentinel lymph node may be the only site of regional microscopic nodal disease and that a subsequent superficial femoral lymph node dissection may not be necessary in patients with early melanoma of the lower extremity after a positive sentinel lymphadenectomy. However, whether the sentinel lymphadenectomy can be used solely as a regional surgical treatment for this subgroup of patients still warrants further evaluation.

Selective sentinel lymphadenectomy for malignant melanoma

To date, selective sentinel lymphadenectomy (SSL) should be considered a standard approach for staging patients with primary invasive melanoma greater than or equal to 1 mm. It is imperative that the multidisciplinary team master the techniques of preoperative lymphoscintigraphy, intraoperative lymphatic mapping, and postoperative pathologic evaluation of the sentinel lymph nodes (SLNs). A SLN is defined as a blue, "hot", or any subsequent lymph node greater than 10% of the in vivo count of the hottest lymph node and as an enlarged or indurated lymph node. Frozen sections are not recommended. For extremity melanoma, delayed SSL may be performed. Preoperative lymphoscintigraphy for extremity melanoma may be done the night before so that surgery can be scheduled as the first case of the following day. Every surgeon who uses blue dye should be cognizant of the potential adverse reaction to isosulfan blue and treatment for such a potential fatal reaction. A complete lymph node dissection is done if the SLN is found to be positive. Elective lymph node dissection should not be done if SSL can be done as a staging procedure. It is important for investigators involved with SSL to follow the clinical outcome of their patients so that the role of SSL can be further defined.

New method of sentinel node identification with ultrasonography using albumin as contrast agent: a study in pigs

The purpose of our study was to verify in animals the possibility of using albumin-enhanced ultrasonography as a modality for sentinel node detection. The nine pigs were injected subcutaneously in the neck with albumin, five with 5% solution and four with 25% solution, and then the regional lymph nodes were observed over time. It was found that, where the 5% solution had been injected, the lymph nodes showed no change, but where the 25% solution had been used, a high echo 1 to 5 mm in size was seen at the hilus of the nearest lymph node. Examination of the excised pathologic specimens of lymph nodes demonstrated that this echo was due to albumin accumulated in the efferent lymphatics. This finding suggested that this technique of ultrasonography using albumin as a contrast agent was an effective new method of identifying sentinel nodes.

Lymphatic Mapping and Sentinel Lymph Node Biopsy

The status of the regional nodal basin remains the most important prognostic indicator of survival. The current standard of care for the management of invasive breast cancer is the complete removal of the tumor, with documentation of negative margins by either mastectomy or lumpectomy, followed by complete axillary lymph node dissection. Data suggest that complete lymph node dissection (CLND) provides better local control of the disease and may actually offer a survival advantage. Lymphatic mapping and sentinel lymph node (SLN) biopsy are clearly changing this long-held paradigm and have the potential to change the standard of surgical care of the breast cancer patient. The purpose of this report is to describe the lymphatic mapping experience at the H. Lee Moffitt Cancer Center and Research Institute. From April 1994 to January 1999, 1,147 consecutive breast cancer patients were enrolled in an institutional review board-approved lymphatic mapping protocol. Lymphatic mapping was performed using Tc99m-labeled sulfur colloid and isosulfan blue dye. An SLN was defined as any blue node and/or any hot node with ex vivo radioactivity counts >/=10 times an excised non-SLN or in situ radioactivity counts >/=3 times the background counts. Lymphatic mapping was successful in identifying the SLN in 1,098 of 1,147 (95.7%) cases. In the first 186 patients, all of whom underwent CLND following SLN biopsy, one false-negative biopsy was encountered for a false-negative rate of 0.83%. The method of diagnosis (excisional versus minimally invasive) does not appear to impact on lymphatic mapping. Tumor size, however, is directly related to the probability of axillary lymph node involvement. Advances in technology and the development of minimally invasive surgical techniques have heralded a new era in surgery. Lymphatic mapping and SLN biopsy may actually prove to be a more accurate method of identifying metastases to the axilla by allowing a more focused pathologic examination of the axillary node(s) at highest risk for metastasis. With adequate training, this technique can be readily implemented as a valuable tool in the surgical treatment of breast cancer.

Sentinel node biopsy in the breast cancer: Possibility of the avoidance of axillary node dissection

(Conclusion) This researching, and many others, indicates that in certain patients (especially T1a and T1b), under precise criteria, when SN metastases are not present, axillary dissection in the breast cancer (10, 22) and all its consequences (lymphoedeama, numbness, pain, limited movement in the shoulder joint) could be avoided. We should remember that nowadays at least 50% of women undergo axillary nodes dissection within the breast cancer operative treatment because of histopathologically negative nodes.

Biology and surgical management of breast cancer

The surgical treatment of breast cancer has been a source of controversy. The controversy arises from the differences in physicians' philosophies regarding the biology of breast carcinoma. Traditionally, surgeons have emphasized the potential therapeutic value of regional lymph node dissection, maintaining that adequate loco-regional treatment is of prime concern in patients with localized tumors. On the other hand, medical oncologists have always stressed the systemic nature of cancer. However, breast cancer is a very heterogeneous disease with an enormous range of different biologic characteristics, and new information is continually becoming available on the natural history of breast cancer. Therefore, we should seek a more rational theory based on the clinical evidence which can explain the biologic characteristics of breast cancer. We have proposed a new spectrum hypothesis as follows: (a)tumor cells traverse lymphatics to lymph nodes by direct extension, and there is an orderly pattern in the early stage of lymph node metastases; (b)regional lymph nodes are able to trap tumor cells but are ineffective or incomplete barriers to tumor cell spread; (c)regional lymph nodes have biologic importance, and a positive lymph node is an indicator of a host-tumor relationship that correlates with the subsequent appearance of distant disease; (d)lymphatic and hematogenous dissemination occur not serially, but in a parallel fashion; (e)many palpable invasive breast cancers are a systemic disease, but non-invasive or minimally invasive breast cancers are likely to be a local disease; (f)early detection and treatment of in-breast cancer improves survival, but variations in regional therapy are unlikely to have a major influence on survival.

No indication for performing sentinel node biopsy in melanoma patients with a Breslow thickness of less than 0.9 mm

In thin melanomas, the involvement of regional nodes is very uncommon. Recent sentinel node (SN) studies have confirmed the absence of positive regional lymph nodes in melanomas < 0.76 mm and a 5% positivity in melanomas between 1.0 and 1.99 mm. The chance of regional lymph node involvement - and therefore whether it is relevant to perform the SN procedure - seems to depend on the Breslow thickness of the primary tumour. However, a Breslow thickness cut-off point has not yet been established. We evaluated a melanoma population that had undergone an SN procedure to determine this point, so that the procedure can be restricted to a smaller group of patients in future. In a total of 348 patients with proven American Joint Committee on Cancer (AJCC) stages I or II cutaneous melanoma with a Breslow thickness > or = 0.5 mm the triple technique was used, consisting of preoperative visualization of the lymph channels from the initial site of the melanoma towards the SN by (dynamic) lymphoscintigraphy, intraoperative visualization of those particular lymph channels and nodes with blue dye, and a gamma probe to measure accumulated radioactivity in radiolabelled lymph nodes. In melanomas thinner than 0.90 mm, no positive SN was found (95% confidence interval 0-5%). This group consisted of 75 patients (22%), with a median follow-up of 31 months. Our data suggest that this procedure need no longer be indicated for almost a quarter of the patient population, because the cut-off point for nodal involvement appears to be a Breslow thickness of 0.90 mm.

Technical issues and pathologic implications of sentinel lymph node biopsy in early-stage breast cancer patients

BACKGROUND AND OBJECTIVES

Recent studies have demonstrated that the sentinel lymph node (sN) can be considered a reliable predictor of axillary lymph node status in breast cancer patients. However, some important issues, such as optimization of the technique for the intraoperative identification of the sN, and the clinical implications of sN metastasis as regards the surgical management of the axilla still require further elucidation. The objectives of this study was to assess (1) the feasibility of sN identification with a combined approach (vital blue dye lymphatic mapping and radioguided surgery, RGS) and the specific contribution of either techniques to the detection of the sN, and (2) the correlation between the size of sN metastasis (micrometastasis < or = 2 mm; macrometastasis > 2), primary tumour size, and the status of nonsentinel nodes (nsN) in the axilla.

METHODS

Between October of 1997 and December of 1999, 212 patients with breast cancer (average age: 61 years; range, 40-79 years) underwent sN biopsy before performing standard axillary dissection. In a subset of 153 patients, both vital blue dye (Patent Blue-V) lymphatic mapping and RGS were used to identify the sN, and the relative contribution of each of the two techniques was assessed.

RESULTS

Overall, the sN was identified in 206 of 212 patients (97.1%); at histologic examination of all dissected nodes, 77 of 206 patients had positive nodes (37.3%). The false-negative rate was 6.5% (5/77), the negative predictive value was 96.3% (129/134), and accuracy was 97.6% (201/206). Among 72 patients with positive sN, micrometastases were detected in 21 cases and macrometastases in 51. When micrometastases only were observed, the sN was the exclusive site of nodal metastasis in 17 of 21 cases (80.9%); in the remaining 4 cases (19.1%), nsN metastases were detected in 3 of 14 pT1c patients (21.5%), and 1 of 5 pT2 patients (20%). Macrometastases were detected in patients with tumors classified as pT1b or larger: the sN was the exclusive site of metastasis in 3 of 4 pT1b patients (75%), in 14 of 29 pT1c patients (48.2%), and in 3 of 18 pT2 patients (16.6%). The specific contribution of the two different techniques used in the identification of the sN was evaluated; the detection rate was 73.8% (113 of 153) with Patent Blue-V alone, 94.1% (144 of 153) with RGS alone, and 98.7% (151 of 153) with Patent Blue-V combined with RGS (P < 0.001). Noteworthy, whenever the sN was identified, the prediction of axillary lymph node status was remarkably similar (93-95% sensitivity; 100% specificity; 95-97% negative predictive value, and 97-98% accuracy) with each of the three procedures (Patent Blue-V alone, RGS alone, or combined Patent Blue-V and RGS).

CONCLUSIONS

Sentinel lymphadenectomy can better be accomplished when both procedures (lymphatic mapping with vital blue dye and RGS) are used, due to the significantly higher sN detection rate, although the prediction of axillary lymph node status remains remarkably similar with each one of the methods assessed. That patients with small tumours (<1 cm) and sN micrometastasis are very unlikely to harbour metastasis in nsN should be considered when planning randomised clinical trials aimed at defining the effectiveness of sN guided-axillary dissection.

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.

The role of sentinel lymph node biopsy in women undergoing prophylactic mastectomy

BACKGROUND

Indications for prophylactic mastectomy (PM) range from LCIS to BRCA 1-2 positive, cosmesis, and cancer phobia. Occult cancers have been found in up to 5% of PM cases. Consequently, consideration must be given to the role of sentinel lymph node (SLN) biopsy as a diagnostic procedure in these patients as PM excludes the subsequent option of SLN biopsy.

METHODS

From April 1994 to November 1999, all patients undergoing PM had SLN biopsy after four quadrant periareolar injections of radiocolloid (450 mci) and blue dye (5 cc). All patients were prospectively accrued to the computerized database of breast patients. The SLN were all evaluated with hematoxylin and eosin (H&E) as well as CAM5.2 cytokeratin immunohistochemical (CK-IHC) stains.

RESULTS

Over a 67-month period, 1,356 patients were mapped; 57 patients underwent PM in which 148 nodes (2.6 nodes per patient) were evaluated. Nodes were examined by routine H&E and CK-IHC staining. Two patients, neither of whom was found to have a cancer in the prophylactic mastectomy breast, were found to have a positive SLN by CK-IHC staining. Infiltrating carcinoma was discovered within the PM breasts of 2 additional patients. Sentinel lymph node biopsy was negative for malignancy by H&E as well as CK-IHC stains. No lymphedema has been detected in PM patients.

CONCLUSIONS

Sentinel node biopsy has been shown to be an accurate and minimally invasive method of evaluating the lymphatic basin. This study shows that the absence of known disease within the breast does not preclude the presence of occult cancer or metastatic nodal disease. Four patients (7%) had a significant change in their surgical management as a direct result of sentinel lymph node biopsy. Two patients were spared the complications of a complete axillary node dissection. This minimally invasive procedure accurately evaluated the known disease status and provided new diagnostic information. Most important, once a mastectomy is performed, the opportunity for SLN biopsy is lost should a cancer be found within the breast specimen.

Reliability of the sentinel node procedure in melanoma patients: analysis of failures after long-term follow-up

BACKGROUND

The sentinel node (SN) concept assumes that early lymphatic metastases, if present, always are found first in the SN. The aim of this study was to determine the reliability of this procedure by establishing the success rate and number of failed procedures during a follow-up period of at least 2 years.

METHODS

From August 1993 to November 1996, 204 consecutive patients with stage I and II cutaneous melanoma underwent SN biopsy by a triple technique. Preoperatively, all patients underwent (dynamic) lymphoscintigraphy. A gamma probe and blue dye helped localize the SN(s) during surgery, and these nodes subsequently were excised. These lymph nodes were step-sectioned and examined by routine and immunohistochemical staining. If the SN contained tumor cells, a lymphadenectomy was performed at a later date.

RESULTS

The median follow-up time was 42 months. The success rate was 99%. Three patients developed a recurrence in the negative SN basin during follow-up, without simultaneous appearance of (locoregional) metastases.

CONCLUSIONS

With a 99% success rate and a 1.5% rate of failed SN procedures (7% false-negative rate) after a median follow-up of 3.5 years, we concluded that the combined triple technique approach of detecting the SN was a reliable method to accurately identify and retrieve the SN.

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.

Estimating the overlap between sentinel lymph nodes and axillary node samples in breast cancer

Management of the axilla in breast cancer patients is a controversial issue. Axillary sampling and sentinel lymphadenectomy are both conservative surgical approaches which aim to stage the disease. These procedures target selective treatment of node-positive patients and seem to allow the omission of axillary clearance in node-negative ones. In this way, they reduce the rate of complications in an otherwise overtreated subset of patients. Forty consecutive patients with palpable T1 and T2 breast carcinoma underwent sentinel lymphadenectomy following mapping with Patent blue dye, with subsequent axillary clearance and excision of the tumor or mastectomy. Then the largest/firmest 3,4,5 and 6 nodes were selected from all the lymph nodes in order to model an axillary sample. It was suggested that these are the nodes that are the most likely to be included in the specimen during sampling, because of their size and consistency. The probability of the sentinel lymph nodes falling into the sample of the 3-6 largest/firmest nodes was calculated. The sentinel nodes predicted the axillary nodal status in 95%, while the samples of the largest 3, 4, 5 and 6 nodes were predictive in 95, 96, 98 and 98%, respectively. The two methods of evaluation displayed a considerable overlap, as the sentinel node would have been included in the 3 6 largest/firmest nodes in 79 92% of the cases, depending on the number of largest nodes evaluated. The overlap was greater after fine needle aspiration of the primary tumor. Although the two alternative staging procedures of 3, 4, 5 or 6 node sampling and sentinel lymphadenectomy with the vital blue dye technique cannot be simultaneously done without one influencing the other, and the first method was only modeled, the results suggest that there is a considerable overlap between the two; axillary sampling may often remove the sentinel lymph nodes.

The impact of axillary lymphadenopathy on further treatment in breast cancer? A model for clinical staging

Clinical assessment is an important part of the breast cancer patients' work-up, but it has low sensitivity and specificity. In a retrospective study, histological slides of axillary clearance specimens were used to model palpability of the axillary lymph nodes. Obvious nodes (enlarged and involving considerable amount of lymphatic and/or metastatic tissue) and nodes equal to or larger than 1 cm or 1.5 cm were counted and the slides were subsequently reviewed. The false positive and negative rates expected on the basis of the model ranged from 24 to 72 % and from 10 to 38 %, respectively. This model (also valid for intraoperative assessment of nodal status by palpation) documents the lack of specificity of clinical staging of the axilla. These results question the practice of excluding patients with palpable axillary lymph node enlargement from less radical staging procedures such as axillary sampling or sentinel node biopsy.