Highest isotope count does not predict sentinel node positivity in all breast cancer patients

Background: Radioisotope mapping is an essential technical component of sentinel lymph node (SLN) biopsy, and most authors define isotope success by an arbitrary threshold SLN-to-background ratio. Few studies have examined the degree to which the relative level of SLN counts correlates with the presence of metastasis. Having removed the SLN with the highest counts, how far should the surgeon persist in removing additional SLN which contain much lower levels of isotope? Methods: We performed SLN biopsy, using both radioisotope and blue dye, in 2285 consecutive patients with stage I-II breast cancer. Successful isotope localization was defined as an ex vivo SLN-to-axillary background count ratio of at least 4:1, and enhanced pathologic analysis (serial sections and immunohistochemistry) was used throughout. Results: Among the 1566 patients with more than one SLN site identified, the SLN contained metastasis in 463 (30%). In 369 (80%) of these SLN-positive cases, the SLN with the highest count contained tumor, but in 94 (20%) it was benign. Among these 94: (1) the counts of the hottest benign SLN exceeded those of the histologically positive SLN by a ratio of at least 10:1 in 31% (29 of 94) of cases, (2) the counts of the positive SLN were < 4:1 those of the axillary background in 16% (15 of 94) of cases, and (3) blue dye failed to identify 27% of positive SLN. No optimum ratio of SLN-to-SLN or SLN-to-background counts identified the positive SLN in all cases. Conclusion:Although the SLN with the highest counts is positive in 80% of breast cancer patients with multiple SLN, neither a relatively high isotope count nor the presence of blue dye consistently predict SLN positivity in all breast cancer patients. For maximum accuracy, SLN biopsy requires (1) the removal of all nodes containing isotope regardless of the relative magnitude of counts, (2) the concurrent use of blue dye to salvage those procedures in which isotope fails, and (3) the removal of all clinically suspicious non-SLN.     

Is the “10% Rule” Equally Valid for All Subsets of Sentinel-Node-Positive Breast Cancer Patients?

Background  In breast cancer, a combination of radioisotope and blue dye mapping maximizes the success and accuracy of sentinel node (SLN) biopsy. When multiple radioactive nodes are present, there is no single definition of isotope success, but the popular “10% rule” dictates removal of all SLN with counts >10% of the most radioactive node. Here we determine how frequently a positive SLN would be missed by the 10% rule. Methods  Between 9/96 and 12/04, we performed 6,369 successful SLN biopsies using ^99mTc sulfur colloid and isosulfan blue dye, removing as SLN all radioactive and/or blue nodes, and taking counts from each node ex vivo. Standard processing of all SLNs with a benign frozen section included hematoxylin and eosin (H&E) staining, serial sectioning, and immunohistochemistry (IHC). Results  33% of patients (2,130/6,369) had positive SLNs. Of these patients, 1,387/2,130 (65%) had >1 SLN identified. The most radioactive SLN was benign in 29% (398/1,387), and 107/1,387 (8%) had a positive SLN that was neither blue nor the hottest. From this group 1.7% (24/1387) of patients had positive SLN with counts <10% radioactive counts of the hottest node. The 10% rule captured 98.3% of positive nodes in patients with multiple SLNs. No patient characteristics were predictive of failure of the 10% rule. Conclusion  With combined isotope and blue dye mapping, the 10% rule is a robust guideline and fails to identify only 1.7% (24/1387) of all SLN-positive patients with multiple SLNs. This guideline appears to be equally valid for all subsets of patients.     

How many lymph nodes are enough during sentinel lymphadenectomy for primary melanoma?

BACKGROUND: Sentinel lymph node (SLN) biopsy has been shown to reliably identify nodal metastases and the subsequent need for further surgical and adjuvant therapy in patients with cutaneous melanoma. Although SLN identification rates have improved with the addition of radioactive colloid to the blue dye technique, it remains unclear how many lymph nodes should be removed to accurately determine the histologic status of the nodal basin. The objective of this study was to determine the optimal extent of SLN biopsy in these patients. METHODS: The records of 633 consecutive patients with melanoma (765 nodal basins) whose primary treatment included SLN biopsy with the use of a combination of blue dye and technetium Tc 99 labeled sulfur colloid were reviewed. SLN biopsy consisted of the removal of all of the blue-stained nodes and all nodes with radiotracer uptake activity of at least twice background. RESULTS: SLN biopsy was successful in 765 of 772 basins (99%). A mean of 1.9 SLNs (median, 2 SLNs) per basin were excised. At least 3 SLNs were removed in 176 basins (23%). The overall histologic status of a basin was always established by the first or second SLN harvested (ie, in no patient was the third or subsequent SLN positive when 1 of the first 2 was not). Of the 124 basins containing lymphatic metastases, the SLN that contained the maximal radiotracer uptake (hottest) and/or stained blue was pathologically positive in 118 basins (95%). In only 6 of the 124 positive basins (5%) was the sole evidence of occult nodal metastases identified in an SLN that was neither blue-stained nor the hottest. All but 1 of these SLNs had counts that were at least 66% of the hottest node in the basin. CONCLUSIONS: With a combined modality approach to SLN biopsy, removal of more than 2 SLNs did not provide information that upstaged any patient with primary melanoma. Removal of additional nonblue SLN(s) that contained radioactive counts of at least twice background but lower than two thirds of the SLNs with maximal radiotracer uptake affected patient management in less than 0.2% of all cases. These findings may be helpful in minimizing the extent of surgery and perhaps in reducing the costs and resource use associated with operating room time and pathologic examination.     

Sentinel lymph node biopsy in breast cancer: an analysis of the maximum number of nodes requiring excision

Sentinel lymph node biopsy (SNB) is now the standard of care in assessment of patients with clinically staged T1-2, N0 breast cancers. This study investigates whether there is a maximum number of sentinel lymph nodes (SLN) that need to be excised without compromising the false-negative (FN) rate of this procedure. Data were prospectively collected for 319 patients undergoing SNB between February 2001 and December 2006 at our institution. This data were analysed, both in terms of the order of SLN retrieval and relative isotope counts of the SLNs, in order to determine the maximum number of SLNs that need to be retrieved without increasing the FN rate. Furthermore, we investigated the relationship between SLN blue dye concentration and the presence of SLN metastases. The SLN identification rate was 97% with no false-negative cases amongst patients undergoing simultaneous axillary clearance historically during technique validation. In patients with SLN metastases, excision of the first 4 SLNs encountered results in the identification of a metastatic SLN in all cases. Although the majority (86%) of SNB metastases are in the hottest node, the SLN containing the metastasis is in the first 4 hottest nodes in 99% of patients with nodal metastases. The remaining 1% of SLN metastases were identified by blue dye. There was no statistically significant association between the SLN blue dye concentration and the presence of SLN metastases. A policy to remove a maximum of four blue and/or hot SLNs along with any palpably abnormal lymph nodes does not result in an increased false-negative rate of detection of SLN metastases.     

Sentinel lymph node biopsies in melanoma: how many nodes do we really need?

BACKGROUND: Sentinel lymph nodes (SLN) biopsy is a widely used method to detect lymphatic spread in patients with cutaneous melanoma. Several methods are used to detect SLNs. Recent reports attempted to identify the adequate number of SLNs to reliably detect malignant spread in regional lymph nodes. METHODS: The radiotracer counts and the pathologic reports of all patients undergoing SLN biopsies were collected prospectively, to determine which of the nodes harboring radiotracer needed to be removed for examination by histopathology between 1998 and 2005. All patients with positive SLN biopsies were investigated in the study. Lymph nodes were ranked according their radiotracer counts and numbered as hottest nodes, second hottest nodes, third hottest nodes, etc. The relationship between radioactivity and the risk of harboring malignancy was determined. RESULTS: Nodal metastases were detected in 55 basins from 53 patients (10.5%). There was a correlation between the radiotracer uptake and risk of harboring malignancy. Excising the 3 hottest nodes and all blue nodes detected 100% of patients with lymphatic malignancy in our series. Most (98%) of positive lymph nodes had radiotracer counts greater than 30% of the hottest node. Only 1 patient (2%) had radioactive count less than 30%, but had visible blue dye. CONCLUSIONS: Removing only the hottest node is inadequate to detect lymphatic spread. On the other hand, removing the 3 hottest nodes and all visible blue nodes is sufficient to detect regional lymphatic spread in patients with cutaneous melanoma. Removing nodes with a radiotracer uptake less than 30% of the hottest nodes may be unnecessary.     

The breast cancer patient with multiple sentinel nodes: when to stop?

BACKGROUND:

During sentinel lymph node (SLN) biopsy for breast cancer, most authors report identifying a mean of 1 to 3 SLNs, but a range of 1 to 8 (or more) SLNs per patient. A significant minority of patients have 4 or more SLNs. Here we seek to determine the significance for the breast cancer patient of finding multiple SLNs, and whether there is an optimal threshold number of SLNs that should be removed.

STUDY DESIGN:

1,561 patients who underwent successful SLN biopsy using blue dye and radioisotope in combination. Each SLN site was categorized prospectively by the operating surgeon as a dye success, an isotope success, or both. All SLNs containing counts at least four times greater than the postexcision axillary background were considered to be isotope successes.

RESULTS:

Fifteen percent of patients (241) had multiple (> 3) SLNs. Ninety-eight percent of node-positive patients (440 of 449) were identified within the first three SLN sites examined. In 2% of all SLN positive patients (9 of 449) or 4% of patients with multiple SLN (9 of 241), a positive SLN was detected at site four or more. In eight patients the first positive SLN was found at sites four or more. Blue dye and isotope were equally effective in identifying metastases in patients with multiple SLNs.

CONCLUSIONS:

Fifteen percent of patients having SLN biopsy for breast cancer have multiple SLNs. Although 98% of positive SLNs were identified within the first three sites sampled, a small number of patients had their first positive SLN at sites 4 to 8. These data suggest that there is no absolute upper threshold for the number of SLNs that should be removed. Sampling a few additional SLNs probably adds little morbidity to the procedure, yet may significantly alter the treatment of some individuals. SLN biopsy should be continued until all blue and hot nodes are removed.     

Sentinel lymph node dissection for breast cancer: how many nodes are enough and which technique is optimal?

BACKGROUND: Controversy exists in sentinel lymph node (SLN) mapping in breast cancer regarding the appropriate number of nodes to remove and the best technique for identification of the SLNs. METHODS: A retrospective chart review from January of 1999 to January of 2004 was performed for all patients undergoing a SLN biopsy examination who had at least 1 positive SLN. RESULTS: We identified 167 patients. A mean of 4.4 SLNs were removed per patient. All of the positive SLNs were identified by node 6. Radiotracer used alone identified 19 positive nodes (11.4%) and blue dye used alone identified 14 positive nodes (8.4%). CONCLUSIONS: Our data show that 100% of positive SLNs are found by 6 nodes removed, thereby supporting the concept that the SLN dissection may not be complete by removing only 1 or 2 nodes or only the hottest node. The use of blue dye or radiotracer alone can contribute to the overall false-negative rate.     

Practical guidelines for optimal gamma probe detection of sentinel lymph nodes in breast cancer: results of a multi-institutional study. For the University of Louisville Breast Cancer Study Group

INTRODUCTION: Multiple radioactive lymph nodes are often removed during the course of sentinel lymph node (SLN) biopsy for breast cancer when both blue dye and radioactive colloid injection are used. Some of the less radioactive lymph nodes are second echelon nodes, not true SLNs. The purpose of this analysis was to determine whether harvesting these less radioactive nodes, in addition to the "hottest" SLNs, reduces the false-negative rate. METHODS: Patients were enrolled in this multicenter (121 surgeons) prospective, institutional review board-approved study after informed consent was obtained. Patients with clinical stage T1-2, N0, M0 invasive breast cancer were eligible. This analysis includes all patients who underwent axillary SLN biopsy with the use of an injection of both isosulfan blue dye and radioactive colloid. The protocol specified that all blue nodes and all nodes with 10% or more of the ex vivo count of the hottest node should be removed and designated SLNs. All patients underwent completion level I/II axillary dissection. RESULTS: SLNs were identified in 672 of 758 patients (89%). Of the patients with SLNs identified, 403 patients (60%) had more than 1 SLN removed (mean, 1.96 SLN/patient) and 207 patients (31%) had nodal metastases. The use of filtered or unfiltered technetium sulfur colloid had no impact on the number of SLNs identified. Overall, 33% of histologically positive SLNs had no evidence of blue dye staining. Of those patients with multiple SLNs removed, histologically positive SLNs were found in 130 patients. In 15 of these 130 patients (11.5%), the hottest SLN was negative when a less radioactive node was positive for tumor. If only the hottest node had been removed, the false-negative rate would have been 13.0% versus 5.8% when all nodes with 10% or more of the ex vivo count of the hottest node were removed (P =.01). CONCLUSIONS: These data support the policy that all blue nodes and all nodes with 10% or more of the ex vivo count of the hottest SLN should be harvested for optimal nodal staging.     

Selective Sentinel Lymph Node Dissection for Melanoma: Importance of Harvesting Nodes with Lower Radioactive Counts without the Need for Blue Dye

Background

Determining how many sentinel lymph nodes (SLNs) should be removed for melanoma is important. The purpose of this study is to determine the frequency at which nodes that are less radioactive than the “hottest” node (which is negative) are positive for melanoma, how low of a radioactivity should warrant harvest, and if isosulfan blue is necessary.

Methods

We reviewed 1,152 melanoma patients who underwent lymphoscintigraphy with technetium, with or without blue dye, and SLN dissection from 1996 to 2008. SLNs with radioactivity ≥10% of the “hottest” SLN, all blue nodes, and all suspicious nodes were removed and analyzed. The miss rate was calculated as the proportion of node positive cases in which the “hottest” SLN was negative.

Results

SLNs were identified in 1,520 nodal basins in 1,152 patients. SLN micrometastases were detected in 218 basins (14%) in 204 patients (18%). In 16% of SLN-positive patients (33/204 patients), the positive SLN was found to have a lower radioactive count than the “hottest” SLN, which was negative. In 21 of these cases, the positive SLNs had radioactivity ≤50% of the “hottest” SLN. The 10% rule significantly reduced the miss rate to 2.5% compared with removal of only the “hottest” SLN (miss rate = 16%). Also, blue dye did not significantly decrease the miss rate compared with radiocolloid alone using the 10% rule.

Conclusions

To decrease the miss rate, all SLNs with ≥10% of the ex vivo radioactivity of the “hottest” SLN should be removed and blue dye is not essential.     

A trend analysis of the relative value of blue dye and isotope localization in 2,000 consecutive cases of sentinel node biopsy for breast cancer.

BACKGROUND: Among the advocates of blue dye, isotope, or combined dye-isotope mapping of the sentinel lymph node (SLN) for breast cancer, there is no universal consensus as to which technique is optimal and whether the relative value of each method changes with increasing experience. The objective of this study was to examine the relative contributions of blue dye and radioisotope to successful identification of the SLN as the SLN-mapping technique evolved over our first 2,000 consecutive cases. STUDY DESIGN: Using the first 2,000 consecutive SLN biopsy procedures for breast cancer, performed by eight surgeons (none previously experienced in SLN techniques) at one institution, using a combined technique of blue dye and isotope mapping, we report the institutional learning curve and the relative contributions of dye and isotope to identifying both the SLN and the positive SLN, by increments of 500 cases. RESULTS: Comparing the first 500 with the most recent 500 cases, success in identifying the SLN by blue dye did not improve with experience, although success in isotope localization steadily increased, from 86% to 94% (p < 0.00005). With the increasing success of isotope mapping, the marginal benefit of blue dye (the proportion of cases in which the SLN was identified by blue dye alone) steadily declined, from 9% to 3% (p = 0.0001). Parallel to this trend, the proportion of positive SLNs identified by blue dye did not change with experience (89% to 90%), but isotope success steadily increased, from 88% to 98% (p = 0.0015). The proportion of positive SLNs identified by blue dye alone declined from 12% to 2% (p = 0.0015). CONCLUSIONS: Using a combined technique of blue dye and radioisotope mapping, and with refinement of the radioisotope technique, we report 97% success identifying the SLN. Although we continue to recommend the use of both methods in SLN mapping for breast cancer, we observe with experience a declining marginal benefit for blue dye.     

The definition of the sentinel lymph node in melanoma based on radioactive counts

Background There is no consensus on the definition of a hot, nonblue sentinel lymph node (SLN), despite the widespread use of radiocolloid in SLN mapping. Methods A retrospective review of 592 patients with malignant melanoma who underwent SLN mapping was performed. Ex vivo SLN counts and nodal bed counts were obtained by using a gamma probe. The size of each metastatic deposit in an SLN was defined as macrometastases (>2 mm), micrometastases (≤2 mm), a cluster of cells, or isolated melanoma cells. Results A total of 1175 SLNs (SLN⁻, n=1041; SLN⁺, n=134) were evaluated. The mean SLN count/bed counts were SLN⁻, 322±980 and SLN⁺, 450±910 (not significant [NS]) (>2 mm, 270±792 [NS]; ≤2 mm, 446±693 [NS]; isolated melanoma cells/cluster of cells, 677±1189 [P=.036]). Overall, 16 (1.4%) of the SLNs collected had an overall ratio of ≤2. This included two positive SLNs (1.5%), both of which contained macrometatic disease. Forty-seven positive nodal basins had at least one negative SLN. The hottest SLNs in these basins were negative for metastatic disease in nine cases (19.1%). In one basin (2.1%), the positive SLN count was <10% of the hottest lymph node count. Conclusions Removal of lymph nodes until the bed count is 10% of the hottest lymph node will remove 98% of positive SLNs. Lymph node tumor burden influences radioactive counts.     

Intradermal radioisotope is superior to peritumoral blue dye or radioisotope in identifying breast cancer sentinel nodes

BACKGROUND: Sentinel lymph node (SLN) mapping and biopsy have emerged as the technique of choice for axillary staging of breast cancer. Several methods have been developed to identify SLNs, including peritumoral or intradermal injection of isosulfan blue dye or technetium sulfur colloid (TSC). We hypothesize that intradermal TSC is the optimal mapping technique and can be used alone to identify SLNs. STUDY DESIGN: From March 1997 through January 2001, 180 women with T1 and T2 invasive breast cancer and clinically negative axilla underwent SLN mapping and biopsy. Peritumoral TSC was injected in 74 patients, 62 of whom also received peritumoral blue dye. Intradermal TSC (above tumor) was performed in 94 patients, 76 of whom also received peritumoral blue dye. Technetium-rich nodes were identified intraoperatively using a hand-held gamma probe and blue nodes were identified visually. Hematoxylin- and eosin-stained SLN sections were examined by light microscopy for breast cancer metastases. RESULTS: Overall, the SLN mapping procedures were successful in 91% of patients. Peritumoral and intradermal TSC were successful in identifying SLNs in 78% and 97% of patients, respectively. Peritumorally injected isosulfan blue was successful in identifying 83% of SLNs. Intradermal TSC was found to be superior to peritumoral TSC and peritumoral blue dye in identifying SLNs (p = 0.00094, chi-squared, and p = 0.020, ANOVA). CONCLUSIONS: SLN mapping by intradermal TSC has a significantly higher success rate than peritumoral TSC or blue dye. There was minimal benefit in identifying additional SLNs with addition of peritumoral blue dye to intradermal TSC. So, SLN mapping and biopsy using intradermal-injected TSC can be used alone to effectively stage the axilla for breast cancer.     

Localization of the sentinel node in breast cancer: identical results with same-day and day-before isotope injection

Background:Although the technique of sentinel lymph node (SLN) biopsy in breast cancer is not fully standardized, an increasing number of centers map the SLN by using radioisotope supplemented by blue dye, and most have injected isotope on the day of surgery. Here we directly compare the results of same-day and day-before isotope injection in a large series of breast cancer patients having SLN biopsy with our mature technique.Methods:Starting with our 961st SLN procedure for breast cancer, 1320 consecutive patients had SLN biopsy after the injection of unfiltered ^99mTc-labeled sulfur colloid given as a single-site, low-volume (0.05 ml) intradermal injection: 933 on the day of surgery (1-day protocol) and 387 on the day before (2-day protocol). All had intraparenchymal injection of blue dye.Results:The two groups were comparable in age, tumor location, histopathologic characteristics, and number of SLNs identified. LSG taken at 2 hours in the 2-day protocol was positive more often than LSG performed at 30 minutes in the 1-day protocol, and nonaxillary sites of lymphatic drainage were seen in <1% of each group. Absolute isotope counts and the ratio of SLN to axillary background counts were similar. Isotope localization of the SLN succeeded in a comparable fraction of patients, as did SLN identification overall.Conclusions:The results of SLN mapping with same-day and day-before injection of radioisotope are virtually identical. The logistical advantages of day-before injection do not compromise the success of the procedure.Presented at the 54th Annual Meeting of the Society of Surgical Oncology, Washington, DC, March 15–18, 2001.     

Intraoperative radio-lympho-scintigraphy improves sentinel lymph node identification for patients with melanoma.

BACKGROUND: The sentinel lymph node (SLN), the first node draining the primary tumor site, has been shown to reflect the histologic features of the remainder of the lymphatic basin in patients with melanoma. Intraoperative localization of the SLN, first proposed by Morton and colleagues, has been accomplished with the use of a vital blue dye mapping technique. Technical difficulties resulting in unsuccessful explorations have occurred in up to 20% of the dissections. OBJECTIVES: The authors aimed to define the SLN using gamma detection probe mapping and to determine whether intraoperative radiolymphoscintigraphy using technetium sulfur colloid and a hand-held gamma-detecting probe could be used to improve detection of all SLNs for patients with melanoma. METHODS: To ensure that all initial nodes draining the primary site were removed at the time of selective lymphadenectomy, the authors used intraoperative radiolymphoscintigraphy to confirm the location of the SLN, which was determined initially with the preoperative lymphoscintigram and the intraoperative vital blue dye injection. PATIENT POPULATION: The patient population consisted of 106 consecutive patients who presented with cutaneous melanomas larger than 0.75 mm in all primary site locations. RESULTS: The preoperative lymphoscintigram revealed that 22 patients had more than one lymphatic basin sampled. Two hundred SLNs and 142 neighboring non-SLNs were harvested from 129 basins in 106 patients. After the skin incision was made, the mean ratio of hot spot to background activity was 8.5:1. The mean ratio of ex vivo SLN-to-non-SLN activity for 72 patients who had SLNs harvested was 135.6:1. When correlated with the vital blue dye mapping, 139 of 200 (69.5%) SLNs demonstrated blue dye staining, whereas 167 of 200 (83.5%) SLNs were hot according to radioisotope localization. With the use of both intraoperative mapping techniques, identification of the SLN was possible for 124 of the 129 (96%) basins sampled. Micrometastases were identified in SLNs of 16 of the 106 (15%) patients by routine histologic analysis. CONCLUSION: The use of intraoperative radiolymphoscintigraphy can improve the identification of all SLNs during selective lymphadenectomy.     

Sentinel lymph node biopsy using indigo carmine blue dye and the validity of '10% rule' and '4 nodes rule'

This is the study which assessed sentinel lymph node biopsy (SNB) using indigo carmine blue dye and the validity of the '10% rule' and '4 nodes rule'. Patients (302) were performed SNB using the combined radioisotope (RI)/indigo carmine dye method. Excised SLNs were confirmed whether they were stained and numbered in order of RI count and the percentage of radioactivity as compared to the hottest node was calculated. The relationship between histological diagnosis, dyeing and RI count was assessed. All the patients were detected SLN. Positive nodes were identified in 84 (27.8%) patients and were identified up to the third degree of hottest. All the hottest positive nodes were stained by indigo carmine. From the results, removing the three most radioactive SLNs identified all cases of nodal metastasis without complications. These stopping rules were valid and useful under indigo carmine use too.     

The effect of changing gamma count threshold on sentinel lymph node accuracy

PURPOSE: Sentinel lymph node (SLN) biopsy has been increasingly accepted in many centers as an alternative to axillary lymph node dissection in the nodal staging of breast cancer. The goal of SLN biopsy is to accurately stage the axilla while minimizing postoperative morbidity. Theoretically, the continuing search for SLNs disrupts additional lymphatics and impacts on operative time. The gamma count threshold is a predefined threshold percentage of the ex vivo count of the "hottest" SLN, which when applied to each individually excised lymph node determines whether a given lymph node is the SLN or a non-SLN. The higher the threshold percentage, the less the number of lymph nodes will meet the criteria of being an SLN. This study examines the hypothesis that changing the gamma count threshold from 10% to 50% will not significantly affect accuracy or the false-negative rate. METHODS: We retrospectively reviewed the charts of patients who underwent SLN biopsy with or without completion axillary lymph node dissection from March 1995 to January 2001 at Walter Reed Army Medical Center. Data were collected on gamma counts for each SLN and histopathology of each SLN. For each SLN ex vivo gamma count, percentage of the ex vivo gamma count of the "hottest" SLN was calculated. RESULTS: The SLN identification success rate was 94% (163 out of 174 patients). On average, 2.07 SLNs were removed per patient and 58% of patients had more than 1 SLN removed (94 out of 163 patients). Only 10% had 4 or more SLNs removed (17 out of 163 patients). Sentinel lymph node metastasis was found in 21% of patients (35 of 163 patients). Of these 35 patients with positive SLNs, 8 patients had a negative "hottest" SLN when a less radioactive SLN was positive for metastasis. Changing the gamma count threshold from 10% to 50% lowers the extrapolated accuracy from 98% to 95% and increases the extrapolated false-negative rate from 8% to 21%. CONCLUSIONS: The accuracy and false-negative rate of SLN biopsy varies based on the lower limit gamma threshold. Maintaining our 10% gamma count threshold results in acceptable accuracy and false-negative rates comparable to reported literature.     

Does breast tumor location influence success of sentinel lymph node biopsy?

BACKGROUND: Controversy exists regarding the influence of sentinel lymph node (SLN) mapping technique or patient variables on the success rate of SLN mapping. We undertook a prospective study in a single institution series to evaluate multiple variables that could adversely affect SLN identification rates. STUDY DESIGN: Data were collected on 174 patients who underwent 177 SLN mapping procedures followed by axillary dissection from October 1996 through January 2000. Patient demographics, body mass index (BMI), biopsy method, tumor size, palpability, and location were recorded. SLNs were identified by blue dye only (n = 31), Tc-99m sulfur colloid only (n = 34), or combined techniques (n = 112). Data were analyzed by logistic regression analysis and expressed as the probability of failure to map the SLN. RESULTS: SLNs were identified successfully in 150 of 177 procedures (85%) with a false negative rate of 3.7%. Mapping success reached 93% using combination blue dye and isotope. Variables found to adversely affect SLN mapping success and the odds ratio of failure (OR) included lower inner quadrant (LIQ) location (OR 35.6), blue dye only (OR 42.4), BMI >30 and upper outer quadrant (UOQ) location (OR 14.6), and nonpalpable UIQ location (OR 25). LIQ location adversely affects mapping success independent of technique, tumor size, or obesity. Obesity and nonpalpability were adverse factors when tumors were located in the UOQ and UIQ, respectively. Age, biopsy technique, and tumor diameter did not affect SLN mapping success. CONCLUSIONS: SLN mapping success is influenced by technique and tumor location, with best results achieved using combined techniques and for lesions located in quadrants other than the LIQ. Obesity and tumor palpability influence success in the context of tumor location.     

Timing of sentinel lymph node mapping after lymphoscintigraphy.

BACKGROUND: Sentinel lymph node (SLN) mapping is an effective technique for staging patients with melanoma. In an attempt to avoid reinjection of radiolabeled colloid and facilitate SLN mapping at the time of surgery, we examined whether residual radioactivity from preoperative lymphoscintigraphy could be used to accurately identify SLNs during surgery 18 to 24 hours later. METHODS: Forty-six patients with newly diagnosed melanoma underwent injection of 0.22-micron filtered technetium 99m-labeled sulfur colloid followed by lymphoscintigraphy. Patients returned the next day for SLN biopsy with Isosulfan blue dye and the hand-held gamma-probe to identify SLNs. Thirty of 46 patients underwent repeat imaging before operation. No patient had reinjection of radiocolloid. RESULTS: Ninety-five SLNs were identified on initial lymphoscintigraphy, and repeat imaging on the day of surgery confirmed all SLNs previously identified. A total of 122 SLNs (2.65 per patient) were resected from 58 basins. Eighty-four (69%) of 122 SLNs stained blue, and 118 (97%) of 122 SLNs had in vivo gamma-counts greater than 4 times background. Microscopic metastases were present in 13 (10.7%) of 122 SLNs in 12 (26.1%) of 46 patients. There have been no recurrences over a mean follow-up time of 320 days. CONCLUSIONS: Intraoperative gamma-probe detection combined with blue dye injection is highly effective in identifying SLNs 18 to 24 hours after injection of 0.22-micron filtered 99mTc-sulfur colloid. Reinjection of radiocolloid is not required. This technique avoids radiopharmaceutical administration in the operating room, minimizes radiation exposure, and increases scheduling flexibility.     

Methylene Blue Dye as an Alternative to Isosulfan Blue Dye for Sentinel Lymph Node Localization

Background: Our study describes the use of methylene blue dye as an alternative to isosulfan blue dye to identify the sentinel lymph node (SLN).Methods: A retrospective analysis was performed of 112 breast cancer patients (113 axillae) who underwent SLN biopsy (SLNB) with methylene blue dye and ^99mTc-labeled sulfur colloid for SLN identification. All SLNs were submitted for intraoperative frozen section analysis, hematoxylin and eosin stain, and immunohistochemical evaluation. Patients with a pathologically negative SLN did not undergo further axillary lymph node dissection.Results: Of 112 patients who underwent SLNB, the SLN was identified in 107 (95.5%); 104 (92.8%) were identified by methylene blue dye. In a subset of 99 patients with recorded isotope status in relation to blue nodes, concordant identification with both dye and isotope was observed in 94 (94.9%). Of patients with identified SLNs, 32 (29.9%) of 107 contained metastatic disease, with 31 (96.9%) of 32 identified by methylene blue dye. The SLN was the only positive node in 18 (60.0%) of 30 patients.Conclusions: SLNB with methylene blue dye is an effective alternative to isosulfan blue dye for accurately identifying SLNs in breast cancer patients.Presented at the Society of Surgical Oncologys 55th Annual Cancer Symposium, Denver, Colorado, March 14–17, 2002.