Will the true sentinel node please stand?

How many sentinel lymph nodes are enough for accurate axillary staging in t1-2 breast cancer?

Purpose

During a sentinel lymph node biopsy (SLNB) for breast cancer, the appropriate number of sentinel lymph nodes (SLNs) to be removed for accurate axillary staging is still controversial. We hypothesized that there might be an optimal threshold number of SLNs. We investigated how many SLNs should be removed to achieve an acceptable accuracy and ensure minimal morbidity.

Methods

We reviewed data of 328 patients with invasive breast cancer who underwent SLNB followed by complete level I and II axillary dissection between January 2004 and December 2005. The false negative rate (FNR) and accuracy of SLNB according to the number of removed SLNs were evaluated.

Results

The mean number of SLNs removed was 3.0 (range, 1-14), and that of total retrieved axillary lymph nodes was 17.5 (range, 10-40). In total, 111 (33.8%) patients had positive nodes on the permanent pathological report. Among them, 12 patients had negative SLNs; thus, the overall FNR of SLNB was 10.8% (12/111) and the accuracy was 96.3% (316/328). The FNR was 26.6% for a single SLN, 8.0% for two, and 11.1% for three. In cases where four or more SLNs were removed, the FNR decreased to 0% and accuracy reached 100%.

Conclusion

Our data suggest that a SLNB should not only remove one or two of the hottest node(s) when other hot nodes exist. We also suggest that four might be an optimal threshold number of SLNs to be removed and that removal of more than four SLNs does not improve axillary staging accuracy.

Analysis of predictive factors for the outcome of complete lymph node dissection in melanoma patients with metastatic sentinel lymph nodes

BACKGROUND

Sentinel lymph node biopsy (SLNB) is a widely accepted procedure to accurately stage patients with melanoma. However, there is no consensus concerning the practical consequences of a positive SLN, since a survival benefit of a complete lymph node dissection (CLND) has not yet been demonstrated.

OBJECTIVE

We wondered whether we could identify a subgroup of patients with metastatic involvement of the SLN who could be excluded from the recommendation to undergo CLND.

METHODS

At the Department of Dermatology at the University of Munich, a total of 213 patients with metastatic SLNs (24.9%) were identified among 854 patients who had undergone SLNB between 1996 and 2007. All SLN-positive patients had been advised to have CLND. Survival analyses were performed by using the Kaplan-Meier approach.

RESULTS

A total of 176 (82.6%) of 213 SLN-positive patients underwent CLND. In this group, 26 patients (14.8%) showed metastatic disease in non-sentinel lymph nodes (NSLN). The 5-year overall survival (OS) was 26.1% in NSLN-positive patients and 74% in NSLN-negative patients. SLN-positive patients who refused CLND had a better prognosis than patients with CLND. Breslow tumor thickness was significantly associated with positive CLND status with higher median values in CLND-positive than CLND-negative patients (3.03 vs 2.22 mm).

LIMITATIONS

The subgroup of patients with metastatic disease in CLND may have been too small to reach statistical significance for other tumor- or patient-related parameters. Mitotic indices of the primary melanomas had not been determined in this retrospective study; thus a possible correlation with lymph node status could not be tested.

CONCLUSION

Among SLN-positive patients, the presence of metastatic NSLN is a highly significant poor prognostic factor. Tumor thickness is a significant prognostic parameter for positive CLND status and might be considered in the decision to perform CLND in case of metastatic SLN.

Prognostic factors associated with sentinel lymph node positivity and effect of sentinel status on survival: an analysis of 1049 patients with cutaneous melanoma

Sentinel lymph node biopsy (SLNB) is a widely accepted staging procedure in patients with melanoma. However, it is unclear which factors predict the occurrence of micrometastasis and overall prognosis and whether SLNB should also be performed in patients with thin primary tumors. At our Department of Dermatology, University of Munich (Germany), 1049 consecutive melanoma patients were identified for SLNB between 1996 and 2007, and were followed-up to assess disease-free and overall survival. Of those, a total of 854 patients were analyzed prospectively. Patients with positive SLN were subjected to selective lymphadenectomy. The association of patient characteristics with SLN was assessed by multivariate logistic regression. Survival curves were performed using the Kaplan-Meier method. Cox proportional hazard regression with different adjustments was used to estimate the effect of SLN on survival. The detection rate of SLN was 97.24%, of which 24.9% were metastatic. Significant parameters upon SLN positivity were tumor thickness and nodular type of melanoma. The 5-year overall survival was 90.1 and 58.1% in SLN-negative and SLN-positive patients, respectively. Upon multivariate analysis tumor thickness and SLN status were significant factors influencing both disease-free survival and overall survival. In conclusion, our data confirm that SLNB is relevant as a diagnostic and staging procedure and that tumor thickness is of predictive importance. SLN status should be taken into account when designing clinical trials and informing patients about the probable course of their disease. Our data suggest that in case of a nodular melanoma subtype SLNB should also be considered at a tumor thickness below 1 mm.

A comprehensive overview of radioguided surgery using gamma detection probe technology

The concept of radioguided surgery, which was first developed some 60 years ago, involves the use of a radiation detection probe system for the intraoperative detection of radionuclides. The use of gamma detection probe technology in radioguided surgery has tremendously expanded and has evolved into what is now considered an established discipline within the practice of surgery, revolutionizing the surgical management of many malignancies, including breast cancer, melanoma, and colorectal cancer, as well as the surgical management of parathyroid disease. The impact of radioguided surgery on the surgical management of cancer patients includes providing vital and real-time information to the surgeon regarding the location and extent of disease, as well as regarding the assessment of surgical resection margins. Additionally, it has allowed the surgeon to minimize the surgical invasiveness of many diagnostic and therapeutic procedures, while still maintaining maximum benefit to the cancer patient. In the current review, we have attempted to comprehensively evaluate the history, technical aspects, and clinical applications of radioguided surgery using gamma detection probe technology.

How many sentinel lymph nodes are enough during sentinel lymph node dissection for breast cancer?

BACKGROUND

: It remains unclear how many sentinel lymph nodes (SLNs) must be removed to accurately predict lymph node status during SLN dissection in breast cancer. The objective of this study was to determine how many SLNs need to be removed for accurate lymph node staging and which patient and tumor characteristics influence this number.

METHODS

: The authors reviewed data for all patients in their prospective database with clinical tumor, lymph node, metastasis (TNM) T1 through T3, N0, M0 breast cancer who underwent lymphatic mapping at their institution during the years 1994 through 2006. There were 777 patients who had at least 1 SLN that was positive for cancer. Simple and multiple quantile regression analyses were used to determine which patient and tumor characteristics were associated with the number of positive SLNs. The baseline number of SLNs that needed to be dissected for detection of 99% of positive SLNs in the total group of patients also was determined.

RESULTS

: The mean number of SLNs removed in the 777 lymph node-positive patients was 2.9 (range, 1-13 SLNs). Greater than 99% of positive SLNs were identified in the first 5 lymph nodes removed. On univariate analysis, tumor histology, patient race, tumor location, and tumor size significantly affected the number of SLNs that needed to be removed to identify 99% of all positive SLNs. On multivariate analysis, mixed ductal and lobular histology, Caucasian race, inner quadrant tumor location, and T1 tumor classification significantly increased the number of SLNs that needed to be removed to achieve 99% recovery of all positive SLNs.

CONCLUSIONS

: In general, the removal of a maximum of 5 SLNs at surgery allowed for the recovery of >99% of positive SLNs in patients with breast cancer. The current findings indicated that tumor histology, patient race, and tumor size and location may influence this number.

What is a sentinel node? Re-evaluating the 10% rule for sentinel lymph node biopsy in melanoma

INTRODUCTION

Many surgeons use the "10% rule" to define whether a lymph node is a sentinel node (SLN) when staging malignant melanoma. However, this increases the number of SLN removed and the time and cost of the procedure. We examined the impact of raising this threshold on the accuracy of the procedure.

METHODS

We reviewed the records of 561 patients with melanoma (624 basins) who underwent SLN with technetium Tc99 labeled sulfur colloid using a definition of a SLN as 10% of that of the node with the highest counts per minute (CPM).

RESULTS

Of the 624 basins, 154 (25%) were positive for metastases. An average of 1.9 nodes per basin were removed (range 1-6). Metastases were found in the hottest node in 137 cases (89% of positive basins, 97% of basins overall). Increasing the threshold above 10% decreased the number of nodes excised and the costs involved, but incrementally raised the number of false negative cases above baseline (a 4% increase for a "20% rule," 5% for a "30% rule," 6% for a "40% rule," and 7% for a "50% rule"). Taking only the hottest node would raise the false negative rate by 11%.

CONCLUSIONS

Although using thresholds higher than 10% for the definition of a SLN will minimize the extent of surgery and decrease the costs associated with the procedure, it will compromise the accuracy of the procedure and is not recommended.

Sentinel lymph node biopsy for breast cancer: How many nodes are enough?

INTRODUCTION

Sentinel lymph node (SLN) biopsy using blue dye and radioisotope often results in the removal of multiple SLNs. We sought to determine whether there is a point where the surgeon can terminate the procedure without sacrificing accuracy.

METHODS

One thousand one hundred ninety-seven patients from University of Michigan and the Mayo Clinic undergoing SLN biopsy formed the study population. Surgeons removed all SLNs until counts within the axilla were less than 10% of the highest node ex vivo and recorded the order in which they were removed.

RESULTS

The mean number of SLNs removed per patient was 2.5 (range 1-9). Approximately 42% of patients had three or more lymph nodes removed, while 19% had four or more lymph nodes removed. Eighteen percent of patients (132/725) at University of Michigan and 22% (103/472) at Mayo Clinic had a positive SLN. Ninety-eight percent (231/235) of patients with lymph node metastases were identified by the 3rd SLN while 100% were identified by the 4th SLN.

CONCLUSION

Among patients undergoing SLN biopsy for breast cancer, the only positive SLN is rarely identified in the 4th or higher node. Terminating the procedure at the 4th node may lower the cost of the procedure and reduce morbidity.

[Intraoperative labeling of sentinel lymph nodes with a combination of vital dye and radionuclide tracer--results in sentinel lymph node-positive patients]

BACKGROUND

Sentinel lymph node biopsy enhances the accuracy of tumor staging in patients with malignant melanoma and can help select candidates for regional lymphadenectomy. There are two techniques for identifying the sentinel lymph node: intradermal injection of a radionuclide tracer or of a blue dye. We evaluated both methods to determine how they can be best utilized to locate a sentinel lymph node.

PATIENTS AND METHODS

In a retrospective study, 323 patients with melanoma (tumor thickness > or = 0.75 mm) who underwent sentinel lymph node biopsy after both radionuclide and blue dye injection were evaluated. The labeling of lymph nodes showing micrometastasis by histopathological examination was determined.

RESULTS

63 patients showed sentinel lymph nodes with micrometastasis. All of these nodes (100 %) were labeled with radionuclide tracer, but only 90 % with blue dye. In 5 patients, only radionuclide labeling identified the histopathologically-positive lymph node. In 36 patients, several sentinel lymph nodes were identified, with the histopathologically-positive nodes usually showing a higher radioactive signal intensity than the negative ones.

CONCLUSION

Since in some patients histopathologically-positive lymph nodes are only labeled by radionuclide tracer, radionuclide labeling is indispensable for locating sentinel lymph nodes. In contrast, labeling with blue dye represents a supplementary method, which can simplify the recognition of the sentinel lymph node during surgery.

Évaluation du taux de récidive ganglionnaire après ganglion sentinelle négatif chez les patients porteurs de mélanome, et analyse des résultats. L’expérience de l’hôpital Saint-Louis, Paris

Melanoma is a malignant tumor, with dominant lymphatic extension. Sentinel lymph node is the first lymph node touched by melanoma. Our retrospective and monocentric study is about 87 patients, between July 1999 and July 2003. The inclusion criteria were malignant melanoma with Breslow level superior or equal 1.5 mm, and/or Clark level superior or equal IV, and/or ulcerated, and/or in regression. Sentinel lymph node has been negative on histological analysis in 75 patients (86.2%). About these 75 patients, we found five metastatic lymph node recurrence (6.66%) in a short notice (median 10.2 months). For the five patients with recurrence, the original slides and tissue blocks were available for reexamination. Then, we found micrometastasis in two patients (40% of occult metastasis). Our rate of lymph node recurrence in patients with sentinel lymph node negative is about 6.66%. Our analysis make us believe that early recurrence are essentially linked to histological analysis limits, and maybe to skip metastasis existence.

Clinical relevance of multiple sentinel nodes in patients with breast cancer

Background

Indiscriminate removal of axillary nodes may not be justified as it may potentially worsen the morbidity of the sentinel lymph node biopsy (SNB) procedure. This study examined the factors associated with removal of multiple sentinel lymph nodes and determined whether there was an upper threshold for the number of sentinel nodes that should be removed.

Methods

A total of 803 patients with breast cancer underwent successful SNB using peritumoral injection of 99mTc-labelled albumin colloid and Patent Blue V dye. SNB was followed by standard axillary treatment at the same operation in all patients.

Results

The mean number of sentinel nodes removed per procedure was 2·2 (range 1–9). Multiple sentinel nodes (mean 2·9, range 2–9) were found in 501 patients (62·4 per cent). The false-negative rate in patients who had one sentinel node harvested was 10 per cent, compared with 1 per cent in patients who had three or more nodes removed (P = 0·010). Factors associated with finding multiple sentinel nodes were age less than 50 years (P = 0·004), low body mass index (P < 0·001), tumour in the outer half of the breast (P = 0·013), sentinel node visualization on lymphoscintigraphy (P < 0·001) and an interval of 12 h or less between radioisotope injection and SNB (P = 0·014). For 99·6 per cent of node-positive tumours, metastasis was detected within the first four sentinel nodes removed.

Conclusion

The identification of multiple sentinel nodes, when present, reduced the false-negative rate. These data suggested that removal of more than four nodes was unnecessary.

Lessons learned from the Sunbelt Melanoma Trial

The Sunbelt Melanoma Trial is an ongoing multicenter prospective randomized trial that involves 79 centers and over 3600 patients from across the United States and Canada. This is one of the first large randomized studies to incorporate molecular staging using reverse transcriptase polymerase chain reaction (RT-PCR). While the results related to the primary endpoints of the study are not yet available, several analyses have shed light on many aspects of sentinel lymph node (SLN) biopsy and melanoma prognostic factors. In particular, we have developed a practical definition of sentinel nodes based on the degree of radioactivity. We have established the low rate of postoperative complications associated with SLN biopsy as compared to complete lymph node dissection. We have identified factors that predict the presence of SLN metastases. In contrast, we have been unable to identify factors that indicate a low risk of non-sentinel node metastases in patients with a positive sentinel node, suggesting that completion lymphadenectomy is appropriate for such patients. We have further established the value of identifying interval or in-transit sentinel nodes, which can be the only site of nodal metastasis. We have evaluated the particular challenges associated with SLN biopsy of head and neck melanomas, have evaluated the patterns of early recurrence, and have identified an interesting correlation between increasing patient age and a number of prognostic factors. Future analyses will evaluate the benefit of early therapeutic lymphadenectomy and early institution of adjuvant interferon alfa-2b therapy, as well as the validity of molecular staging.

The effect of lymphatic tumor burden on sentinel lymph node biopsy results

Increasing tumor burden in the axilla, as determined by the number of positive lymph nodes, adversely affects sentinel lymph node (SLN) identification and false-negative rates. The University of Louisville Breast Cancer Sentinel Lymph Node Study is a prospective, multi-institutional study. All enrolled patients underwent SLN biopsy, followed by complete level I/II axillary dissection. Participating surgeons represent a variety of practice settings, mostly community-based private practice. A total of 229 surgeons enrolled 2206 patients between August 1997 and November 2000. SLN biopsy was performed using blue dye injection alone, radioactive colloid alone, or a combination of the two agents. Two key parameters used to measure SLN biopsy success are the SLN identification rate and SLN false-negative rate. The overall SLN identification and false-negative rates were 92.5% and 8.0%, respectively. With increasing numbers of positive axillary nodes, there was a decreased sentinel node identification rate. There was no difference in the false-negative rate with increasing axillary tumor burden. Increased tumor burden in the axilla (as determined by the mean number of positive nodes) is associated with failure to identify a SLN in some cases, but is not an explanation for false-negative results. Standard axillary dissection should be performed when a SLN cannot be identified.

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 biopsy for breast cancer: impact of the number of sentinel nodes removed on the false-negative rate

BACKGROUND

Numerous studies have demonstrated that sentinel lymph node (SLN) biopsy can accurately determine axillary nodal status for breast cancer, but unacceptably high false negative rates have also been reported. Attention has been focused on factors associated with improved accuracy. We have previously shown that injection of blue dye in combination with radioactive colloid reduces the false negative rate compared with injection of blue dye alone. We hypothesized that this may be from the increased ability to identify multiple sentinel nodes. The purpose of this analysis was to determine whether removal of multiple SLNs results in a lower false negative rate.

STUDY DESIGN

The University of Louisville Breast Cancer Sentinel Lymph Node Study is a prospective multiinstitutional study. Patients with clinical stage T1-2, N0 breast cancer were eligible for enrollment. All patients underwent SLN biopsy using blue dye alone, radioactive colloid alone, or both agents in combination, followed by completion level I and II axillary dissection.

RESULTS

A total of 1,436 patients were enrolled in the study from August 1997 to February 2000. SLNs were identified in 1,287 patients (90%), with an overall false negative rate of 8.3%. A single SLN was removed in 537 patients. Multiple SLNs were removed in 750 patients. The false negative rates were 14.3% and 4.3% for patients with a single sentinel node versus multiple sentinel nodes removed, respectively (p = 0.0004, chi-square). Logistic regression analysis revealed that use of blue dye injection alone was the only factor independently associated with identification of a single SLN (p<0.0001), and patient age, tumor size, tumor location, surgeon's previous experience, and type of operation were not significant.

CONCLUSIONS

The ability to identify multiple sentinel nodes, when they exist, improves the diagnostic accuracy of SLN biopsy. Injection of radioactive colloid in combination with blue dye improves the ability to identify multiple sentinel nodes compared with the use of blue dye alone.

Sentinel lymph node biopsy for melanoma: how many radioactive nodes should be removed?

BACKGROUND

Sentinel lymph node (SLN) biopsy has become a standard method of staging patients with cutaneous melanoma. Sentinel lymph node biopsy usually is performed by intradermal injection of a vital blue dye (isosulfan blue) plus radioactive colloid (technetium sulfur colloid) around the site of the tumor. Intraoperative gamma probe detection has been shown to improve the rate of SLN identification compared to the use of blue dye alone. However, multiple sentinel nodes often are detected using the gamma probe. It is not clear whether these additional lymph nodes represent true sentinel nodes, or second-echelon lymph nodes that have received radiocolloid particles that have passed through the true sentinel node. This analysis was performed to determine the frequency with which these less radioactive lymph nodes contain metastatic disease when the most radioactive, or "hottest," node does not.

MATERIALS AND METHODS

In the Sunbelt Melanoma Trial, 1184 patients with cutaneous melanoma of Breslow thickness 1.0 mm or more had sentinel lymph nodes identified. Sentinel lymph node biopsy was performed by injection of technetium sulfur colloid plus isosulfan blue dye in 99% of cases. Intraoperative determination of the degree of radioactivity of sentinel nodes (ex vivo) was measured, as well as the degree of blue dye staining.

RESULTS

Sentinel nodes were identified in 1373 nodal basins in 1184 patients. A total of 288 of 1184 patients (24.3%) were found to have sentinel node metastases detected by histology or immunohistochemistry. Nodal metastases were detected in 306 nodal basins in these 288 patients. There were 175 nodal basins from 170 patients in which at least one positive sentinel node was found and more than one sentinel node was harvested. Blue dye staining was found in 86.3% of the histologically positive sentinel nodes and 66.4% of the negative sentinel nodes. In 40 of 306 positive nodal basins (13.1%), the most radioactive sentinel node was negative for tumor when another, less radioactive, sentinel node was positive for tumor. In 20 of 40 cases (50%), the less radioactive positive sentinel node contained 50% or less of the radioactive count of the hottest lymph node. The cervical lymph node basin was associated with an increased likelihood of finding a positive sentinel node other than the hottest node.

CONCLUSIONS

If only the most radioactive sentinel node in each basin had been removed, 13.1% of the nodal basins with positive sentinel nodes would have been missed. It is recommended that all blue lymph nodes and all nodes that measure 10% or higher of the ex vivo radioactive count of the hottest sentinel node should be harvested for optimal detection of nodal metastases.

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.