Sentinel lymph node dissection and the current status of American trials on breast lymphatic mapping

Lymphoscintigraphy with peritumoral injection versus lymphoscintigraphy with subdermal periareolar injection of technetium-labeled human albumin to identify sentinel lymph nodes in breast cancer patients

BACKGROUND

Preoperative lymphoscintigraphy is without doubt a valid method for the detection of the sentinel lymph node (SLN). There has been considerable debate regarding the optimal site for the introduction of the tracer; various sites include peritumoral (PT), periareolar (PA), subdermal, and intradermal injection.

PURPOSE

To evaluate retrospectively the lymphoscintigraphic identification rate of peritumoral (PT) injection versus subdermal periareolar (PA) injection in the detection of SLNs in breast cancer.

MATERIAL AND METHODS

Between October 2002 and December 2011, a cohort of 906 consecutive patients with biopsy proven breast cancer underwent 914 SLN biopsy procedures. A total of 339 procedures (Group A) were performed using a PT deep injection of radiotracer while 575 procedures (Group B) adopted a subdermal PA injection of radiotracer towards the upper outer quadrant, regardless of the site of the carcinoma. All the patients underwent synchronous excision of the breast cancer and SLN biopsy.

RESULTS

SLNs were identified in the lymphoscintigram in 308/339 cases (90.85%) of Group A (PT injection) and in 537/575 cases (93.39%) of Group B (PA injection). Furthermore, in 2/339 patients (0.58%) of Group A, internal mammary lymph nodes were found at lymphoscintigraphy, whereas no internal mammary sentinel nodes were found in the Group B patients. The intraoperative identification rate of axillary SLNs was 99.41% (337 of 339) in the Group A patients and 99.65% (573 of 575) in the Group B patients. There was no significant difference in the two groups between the incidence of the number of SLNs detected and the incidence of identification of positive SLNs.

CONCLUSION

PT versus PA injection of radiotracer showed comparable success rates for axillary SLN identification, and can be considered a rapid and reliable method.

Identification of lymphatic pathway involved in the spread of bladder cancer: Evidence obtained from fluorescence navigation with intraoperatively injected indocyanine green

INTRODUCTION

We identify lymphatic vessels draining from the bladder by using fluorescence navigation (FN) system.

METHODS

In total, 12 candidates for radical cystectomy and pelvic lymph node dissection (PLND) were included in this study. After an indocyanine green (ICG) solution was injected into the bladder during radical cystectomy, lymphatic vessels draining from the bladder were analyzed using a FN system. PLND was based on the lymphatic mapping created from the FN measurements (in vivo probing) in the external iliac, obturator and internal iliac regions; after PLND, the fluorescence of the removed lymph nodes (LNs) was analyzed on the bench (ex vivo probing).

RESULTS

There were no patients with complications associated with the intravesical ICG injection. A lymphatic pathway along inferior vesical vessels to internal iliac LNs was clearly illustrated in 7 cases. Under in-vivo probing, the fluorescence intensity of internal iliac nodes was greater than that of external iliac or obturator nodes. Under ex-vivo probing, the fluorescence intensity of internal iliac and obturator nodes was greater than that of external iliac nodes.

CONCLUSIONS

Using an FN system after injecting ICG during a radical cystectomy operation is a safe and rational approach to detecting the lymphatic channel draining from the bladder.

GeneSearch™ BLN Assay could replace frozen section and touch imprint cytology for intra-operative assessment of breast sentinel lymph nodes

BACKGROUND

Breast cancer sentinel lymph node (SLN) biopsy has become a common procedure. The GeneSearch™ Breast Lymph Node Assay is a real-time reverse-transcriptase polymerase chain reaction assay for detecting nodal metastases larger than 0.2 mm. The trial is a prospective multi-center clinical trial conducted to validate the assay in China.

METHODS

Four hundred and seventy-nine consecutive prospective patients were enrolled from six centers. SLNs were sectioned along the short axis into multiple blocks. Odd blocks were tested by the assay intra-operatively, and even blocks were assessed by post-operative histology. Six 4- to 6-μm-thick sections were taken every 150 μm per block. In addition, intra-operative histological assessments were performed on the even blocks of 214 patients by frozen section (FS) and all blocks of 156 patients by touch imprint cytology (TIC).

RESULTS

A total of 1046 SLNs were excised. Overall performance of the assay compared to post-operative histology was accuracy of 91.4 %, sensitivity of 87.5 %, and specificity of 92.9 %. There were no significant differences in assay performance of each center. After a learning curve of about 10 cases, the assay could be performed in a median time of about 35 min. The sensitivity of the assay was similar to the FS (84.9 %, P = 0.885) and was significantly higher than the TIC (70.0 %, P = 0.007) while the specificity of all were comparable.

CONCLUSION

The GeneSearch™ Breast Lymph Node Assay is an accurate and rapid intra-operative assay for breast SLNs and it can replace FS and TIC for application.

Comparative study of one-step nucleic acid amplification assay, frozen section, and touch imprint cytology for intraoperative assessment of breast sentinel lymph node in Chinese patients

Conventional procedures for the intraoperative assessment of breast cancer sentinel lymph nodes (SLNs) are frozen section (FS) and touch imprint cytology (TIC). The one-step nucleic acid amplification (OSNA) assay is a novel molecular technique. The aim of this study was to evaluate the optimal approach by comparing OSNA assay, FS, and TIC. Five hundred and fifty-two consecutive patients were enroled from five study centers in China. The SLNs were cut into alternating 2 mm blocks. The odd blocks were tested by the OSNA assay intraoperatively, and the even ones were assessed by postoperative histology (four 4- to 6-μm-thick sections were taken every 200 μm per block). In addition, intraoperative histological assessments were carried out on the even blocks of 211 patients by FS and all blocks of 552 patients by TIC. Overall performance of the assay compared to postoperative histology was: accuracy 91.4%; sensitivity 83.7%; and specificity 92.9%. The sensitivity of the assay was higher than FS (211 patients, 77.6% vs 69.7%; not significant, P = 0.286) and was significantly higher than TIC (552 patients, 83.6% vs 76.2%; P = 0.044). When assessing nodes with micrometastases, the sensitivity of the assay was higher than FS (17 nodes, 47.1% vs 23.5%; not significant, P = 0.289) and was significantly higher than TIC (48 nodes, 62.5% vs 35.4%; P = 0.007). The study indicated that the OSNA assay is an accurate and rapid intraoperative assay for assessing breast SLNs and it can replace FS and TIC for application in general medical practice. The trial was registered as: OSNA assay China Registration Study.

CLINICAL TRIAL REGISTRATION NUMBER

China Breast Cancer Clinical Study Group 001c.

Identification of lymphatic pathway involved in the spreading of prostate cancer by fluorescence navigation approach with intraoperatively injected indocyanine green

OBJECTIVE

: The objective of this study was to identify lymphatic vessels draining from the prostate by using a fluorescence navigation (FN) system.

METHODS

: Fourteen subjects were candidates for radical retropubic prostatectomy (RRP) and pelvic lymph node dissection (PLND). After an indocyanine green solution was injected into the prostate during RRP, lymphatic vessels draining from the prostate were analyzed using a FN system. After PLND based on lymphatic mapping by the FN system (in vivo probing) was performed in the external iliac, obturator and internal iliac regions; the fluorescence of the removed lymph nodes (LNs) was analyzed on the bench (ex vivo probing).

RESULTS

: Under in vivo and ex vivo probing, the fluorescence intensity of internal iliac nodes was greater than that of external iliac or obturator nodes.

CONCLUSION

: The current study suggests that using a FN system after injecting indocyanine green is a safe and rational approach for detecting the lymphatic channel draining from the prostate. The major lymphatic pathway involved in the spreading of prostate cancer appears to relate to internal iliac LNs, which would mean that the standard PLND covering external iliac and obturator regions would not keep the cancer from spreading.

Timing of sentinel lymph node biopsy in patients receiving neoadjuvant chemotherapy for breast cancer

OBJECTIVE

To address optimal timing of sentinel lymph node biopsy (SLNB) in breast cancer patients undergoing neoadjuvant treatment.

METHODS

The study population included 117 patients with locally advanced cancer with clinically negative nodes treated with primary chemotherapy. Group 1 underwent SLNB and completion axillary lymph node dissection (ALND) in conjunction with lumpectomy/mastectomy, after neoadjuvant treatment (n = 31). Group 2 underwent SLNB followed by neoadjuvant therapy and subsequently surgery and completion of ALNDs (n = 58). Group 3 was treated using the same sequence as group 2, however, completion ALND was performed only for patients with positive sentinel lymph nodes (SLNs) (n = 28).

RESULTS

SLN identification was lowest in group 1 compared to groups 2 and 3 (87% and 98.8% respectively; P = <0.05). The highest false negative rate was in group 1 (15.8% compared with 0% in group 2).

CONCLUSION

Neoadjuvant treatment lowers the SLN identification rate, possibly due to fibrosis within the axilla, and increases the false negative rate due to downstaging. SLN biopsy prior to chemotherapy could give a more accurate evaluation of axillary status, unaffected by any previous therapeutic intervention.

Clinical validation of a molecular assay for intra-operative detection of metastases in breast sentinel lymph nodes

BACKGROUND

In breast cancer patients, the status of the sentinel lymph nodes (SLNs) has been shown to accurately reflect the presence of metastases in the axillary lymph nodes (ALNs). Intra-operative SLN evaluation by frozen section histology may miss positive cases, leading to a second surgery for complete ALN dissection. Permanent section histology itself has tissue sampling limitations and is partially dependent on pathologist expertise.

METHODS

A prospective study (N=78) was conducted in our institution to validate a new intra-operative molecular assay, the GeneSearch breast lymph node (BLN) assay. This assay quantifies the expression of mammaglobin and cytokeratin-19 genes using quantitative RT-PCR technology to determine SLN status. Fresh SLN sections (2 mm thick) were analyzed alternatively by BLN assay or post-operative histology (haematoxylin-eosin and immunohistochemistry). The subject was considered positive when histology revealed a focus >0.2 mm.

RESULTS

BLN assay results corroborated with histologic results in 75 out of 78 patients for an overall agreement of 96%, a sensitivity of 92%, and a specificity of 97%. The positive and negative predictive values of the BLN assay were of 86% (12/14) and 98% (63/64), respectively. Interestingly, a statistically significant correlation was observed between the metastases' histologic size and both assay markers' expression levels as represented by cycle time to positivity (rho > or = 0.71, all p<0.0001).

CONCLUSIONS

The performance of the BLN assay in identifying nodal metastases >0.2 mm was similar to that of permanent section histology, with the added advantages of an objective and rapid output that could be used for intra-operative decision to remove additional ALN.

Sentinel lymph node mapping for primary breast cancer

The tumor status of the axillary lymph nodes is the single most important predictor of survival for patients with primary breast cancer. Because of its essential role in staging, regional control, and perhaps survival, axillary lymph node dissection (ALND) has long been the standard of care for patients with operable breast cancer. During the past decade, the introduction and development of sentinel lymph node dissection (SLND) for primary breast cancer have allowed surgeons to determine the tumor status of the axilla without a standard level I and II ALND. Several well-designed studies have documented that SLND is an effective way of assessing axillary nodal status with minimal morbidity and high accuracy. We address the current status and future directions of SLND for primary breast cancer.

Detection of Sentinel Node Micrometastasis by Step Section and Immunohistochemistry in Patients With Prostate Cancer

PURPOSE

The role of step section and immunohistochemistry for diagnosing sentinel node micrometastases and the sentinel node concept in patients with prostate cancer was investigated. In patients administered neoadjuvant hormone therapy its influence on the sentinel node concept and metastasis diagnosis was also investigated.

MATERIALS AND METHODS

Of 62 patients without metastasis enrolled in our study 42 were eligible for analysis. The prostate was injected with the radioactive tracer (99m)technetium phytate 5 to 6 hours before surgery. A planar image and a fusion image with x-ray computerized tomography and single photon emission computerized tomography were obtained 3 hours after tracer injection. Extended lymph node dissection and lymphatic mapping were performed to verify the sentinel node concept. Lymph node metastasis was histologically confirmed by routine hematoxylin and eosin, and thereafter by immunohistochemistry using 250 mum step-sectioned slides.

RESULTS

The mean number of dissected lymph nodes was 26.3 per patient. Hot nodes were noted in 41 of 42 patients. The sensitivity and specificity of hot node prediction of lymph node metastasis were 92.3% and 100%, respectively. On routine hematoxylin and eosin examination lymph node metastases were found in 4 of 27 patients with and in 4 of 15 without neoadjuvant hormone therapy. Step section and immunohistochemistry identified micrometastasis in 5 more patients with neoadjuvant hormone therapy.

CONCLUSIONS

The validity of the sentinel node concept in conjunction with the detection of micrometastases was considered to be high. Furthermore, it was suggested that the efficacy of metastasis diagnosis may also be enhanced, especially in patients receiving neoadjuvant hormone therapy.

Axillary Management After Sentinel Lymph Node Biopsy in Breast Cancer Patients

According to the available data, sentinel lymph node (SLN) biopsy is proving to be an accurate staging technique with less post-surgical morbidity than standard axillary lymph node dissection (ALND). Survival benefits associated with SLN biopsy and, as well as the significance of IHC detected micrometastases have yet to be determined. The long term results of several multicenter trials are pending, yet preliminary results are in favor of abandoning ALND in favor of the less invasive alternative. Despite this, ALND remains the standard of care in breast cancer patients with clinically palpable axillary lymph nodes that are suspicious for metastatic disease. Although controversial, many clinicians believe that axillary metastases will precede systemic spread of disease. Therefore, axillary clearance of clinically palpable nodes could potentially quell the progression of metastases. Regardless of whether or not this theory is true, not many would argue against debulking suspicious nodal disease.

Multimarker RT-PCR assay for the detection of minimal residual disease in sentinel lymph nodes of breast cancer patients

The presence of metastases in lymph nodes is the most powerful prognostic factor in breast cancer patients. Routine histological examination of lymph nodes has limited sensitivity for the detection of breast cancer metastases. The aim of the present study was to develop a multimarker reverse transcriptase-polymerase chain reaction (RT-PCR) assay for the detection of minimal residual disease in sentinel nodes of breast cancer patients. RNA was extracted from 30 sentinel lymph nodes (SLN) obtained from 28 patients, three primary breast cancers (positive controls), three lymph nodes from patients with benign diseases, and peripheral blood lymphocytes of 10 healthy volunteers (negative controls). RT-PCR was performed using the following markers; cytokeratin (CK)-19, NY-BR-1 and mammaglobin B. RT-PCR results were compared to enhanced histopathologic examination and immunohistochemistry (IHC). All three positive controls showed strong PCR amplification for all three markers. None of the 13 negative controls was amplified by any of the three markers. Among the 30 SLN analysed, breast cancer metastases were detected in six SLNs by routine histology, in eight by IHC and in 15 by RT-PCR. We conclude that a multimarker RT-PCR assay probing for NY-BR-1, mammaglobin-B, and CK-19 is more sensitive compared to enhanced pathologic examination. This method may prove to be of value in breast cancer staging and prognosis evaluation.

Molecular analysis improves sensitivity of breast sentinel lymph node biopsy: results of a multi-institutional prospective cohort study

BACKGROUND

Pathologic evaluation may lack the sensitivity required for accurate staging of the axilla in breast cancer patients. We have completed enrollment of a multi-institutional prospective cohort study designed to determine if molecular analyses can improve axillary staging. In subset analyses, we have attempted to address the following questions: (1) Does molecular analysis improve the sensitivity of sentinel lymph node biopsy (SLNB) and (2) is the sentinel lymph node (SLN) hypothesis valid at the molecular level?

METHODS

Four hundred eighty-nine subjects with T1, T2, or T3 breast cancer and no evidence of axillary lymph node (ALN) involvement were enrolled. ALNs were analyzed by routine pathology (hematoxylin-eosin staining), and by multimarker real-time reverse transcriptase-polymerase chain reaction analysis CRT-PCR to detect breast cancer metastases. Pathology and molecular data for both SLNs and nonsentinel ALNs were available for a subset of 207 subjects.

RESULTS

The sensitivity of pathologic analysis of the SLN to predict the pathologic status of ALNs was 84.1%. The sensitivity of combining pathologic with molecular analysis of the SLN to predict the pathologic status of ALNs was 92.8%, a statistically significant increase in sensitivity (P = .031 by the McNemar test for correlated proportions). Finally, the sensitivity of combining pathologic with molecular analysis of the SLN to predict the pathologic or molecular status of ALNs was 85.4%.

CONCLUSIONS

The combination of pathologic and molecular analysis of SLNs resulted in the highest sensitivity for prediction of the pathologic status of ALNs. The data also provide evidence that the SLN hypothesis remains valid at the molecular level.

Update on detection of sentinel lymph nodes in patients with breast cancer

Sentinel lymph node biopsy is now the practice of choice for the management of many patients with breast cancer. This was not true in the early 1990s, when the first such procedures were performed and protocols for such were refined often. This was also not true in the first years of the 21st century, when a decade of collective experience and information acquired from numerous clinical investigations dictated additional subtle and not-so-subtle refinements of the procedures. However, it is true today; reports of the latest round of clinical investigations indicate that there are several breast cancer sentinel node procedures that result in successful identification of potential sentinel nodes in nearly all patients who are eligible for such procedures. A significant component of many of these successful sentinel node procedures is a detection and localization protocol that involves radiotracer methodologies, including radiopharmaceutical administration, preoperative nuclear medicine imaging, and intraoperative gamma counting. The present state and roles of nuclear medicine protocols used in breast cancer sentinel lymph node biopsy procedures is reviewed with emphasis on discussion of recent results, unresolved issues, and future considerations. Included are brief reviews of present radiotracer and blue-dye techniques for node localization, including remarks about injection strategies, counting probe technology, and radiation safety. Included also are discussions of on-going investigations of the implications of the presence of micrometastases; of the management value of detection, localization, and excision of extra-axillary nodes such as internal mammary nodes; and of the broad range of recurrence rates presently being reported. Remarks on the present and possible near- and long-term roles for nuclear medicine in the staging of breast cancer patients including comments on positron emission tomography and intraoperative imaging conclude the article.