Sentinel Node Biopsy in the Evaluation of the Internal Mammary Node Chain in Patients with Breast Cancer

Current technical overviews of sentinel lymph node biopsy for breast cancer

Sentinel lymph node biopsy (SLNB) is based on the hypothesis that the sentinel lymph node (SLN) reflects the lymph-node status and a negative SLN might allow complete axillary lymph node dissection (ALND) to be avoided. Although the survival outcome is still unknown, this technique has already become a standard of care for breast cancer patients. However, it is still important to discuss current techniques and some controversies. This article reviews these issues for a variety of SLNB techniques.

Breast Cancer With Isolated Internal Mammary Lymph Node Metastasis

Internal mammary (IM) lymph nodes can be seen on sonograms. It is important to recognize the sonographic features that make IM nodes worrisome for metastatic disease. Breast cancer, especially when located in the medial breast, can have IM node involvement without axillary lymphadenopathy. Prognosis, staging, and treatment will be altered based on lymph node involvement found with breast cancer. Breast sonography has been warranted following mammographically detectable densities and/or palpable abnormalities.

Lymphoscintigraphic sentinel node identification in patients with breast cancer: the role of SPECT-CT

PURPOSE

Lymph node status is a major factor in determining the stage, appropriate therapy and outcome in patients with breast cancer. It is therefore of clinical importance to accurately identify all sentinel nodes (SNs) for each individual tumour before surgery. The purpose of this study was to assess the role of SPECT-CT lymphoscintigraphy in SN identification in patients with breast cancer.

METHODS

Lymphoscintigraphy comprising planar and SPECT-CT acquisition was performed in 157 consecutive patients with breast cancer (mean age 54.7+/-10.6, range 27-81 years) with a palpable mass (n=100), with a non-palpable mass (n=52) or post lumpectomy (n=5). Planar and SPECT-CT images were interpreted separately and the two imaging techniques were compared with respect to their ability to identify hot nodes.

RESULTS

Planar imaging alone was negative for identification of hot nodes in 15% of the patients. SPECT-CT alone was negative in 10% and both techniques were negative in 9% of the patients. Forty-six of the total of 361 (13%) hot nodes identified by lymphoscintigraphy were detected only on SPECT-CT, including 21 nodes obscured by the scattered radiation from the injection site, nine adjacent nodes misinterpreted on planar images as a single node and 16 nodes which were missed on planar images and detected on SPECT data. SPECT-CT detected additional sites of drainage unexpected on planar images, including axillary (n=23 patients), internal mammary (n=5 patients), interpectoral (n=3 patients) and intramammary (n=2 patients) lymph node sites. Fourteen of the 329 (4%) hot lesions seen on planar images were false positive non-nodal sites of uptake that were accurately assessed by SPECT-CT and further validated by surgery. In a single patient, SPECT-CT was negative while planar images identified the SN.

CONCLUSION

SPECT-CT may improve the preoperative localisation of draining nodes in patients with breast cancer. It may detect hot nodes missed by planar imaging, exclude non-nodal false positive sites of uptake and accurately localise axillary and extra-axillary nodes.

American Society of Clinical Oncology guideline recommendations for sentinel lymph node biopsy in early-stage breast cancer

PURPOSE

To develop a guideline for the use of sentinel node biopsy (SNB) in early stage breast cancer.

METHODS

An American Society of Clinical Oncology (ASCO) Expert Panel conducted a systematic review of the literature available through February 2004 on the use of SNB in early-stage breast cancer. The panel developed a guideline for clinicians and patients regarding the appropriate use of a sentinel lymph node identification and sampling procedure from hereon referred to as SNB. The guideline was reviewed by selected experts in the field and the ASCO Health Services Committee and was approved by the ASCO Board of Directors.

RESULTS

The literature review identified one published prospective randomized controlled trial in which SNB was compared with axillary lymph node dissection (ALND), four limited meta-analyses, and 69 published single-institution and multicenter trials in which the test performance of SNB was evaluated with respect to the results of ALND (completion axillary dissection). There are currently no data on the effect of SLN biopsy on long-term survival of patients with breast cancer. However, a review of the available evidence demonstrates that, when performed by experienced clinicians, SNB appears to be a safe and acceptably accurate method for identifying early-stage breast cancer without involvement of the axillary lymph nodes.

CONCLUSION

SNB is an appropriate initial alternative to routine staging ALND for patients with early-stage breast cancer with clinically negative axillary nodes. Completion ALND remains standard treatment for patients with axillary metastases identified on SNB. Appropriately identified patients with negative results of SNB, when done under the direction of an experienced surgeon, need not have completion ALND. Isolated cancer cells detected by pathologic examination of the SLN with use of specialized techniques are currently of unknown clinical significance. Although such specialized techniques are often used, they are not a required part of SLN evaluation for breast cancer at this time. Data suggest that SNB is associated with less morbidity than ALND, but the comparative effects of these two approaches on tumor recurrence or patient survival are unknown.

Lower and central tumor location correlates with lymphoscintigraphy drainage to the internal mammary lymph nodes in breast carcinoma

BACKGROUND

Radiation to the internal mammary chain (IMC) may be indicated for breast carcinoma patients with positive axillary sentinel lymph nodes (SLNs) and lymphoscintigraphic evidence of drainage to the IMC. The purpose of this study was to identify predictors of IMC drainage in patients with positive axillary SLNs.

METHODS

The records of 297 breast carcinoma patients with positive axillary SLNs and preoperative lymphoscintigraphy were reviewed between 1995 and 2002. Radiolabeled colloid was injected peritumorally with lymphoscintigraphy performed 30-60 minutes later. Drainage to the regional nodes of 279 patients was seen on lymphoscintigraphy. Associations among patient and tumor-related factors and drainage to the IMC were examined.

RESULTS

Drainage to the IMC on lymphoscintigraphy was seen in 63 patients (21%). IMC drainage only occurred in 4 patients, and 59 patients had both axillary and IMC drainage. The only variable that correlated with IMC drainage was tumor location (P = 0.017). Rates of drainage to the IMC were 14.1% for upper outer quadrant (n = 128), 16.7% for upper inner quadrant (n = 30), 31.6% for lower outer quadrant (n = 19), 42.9% for lower inner quadrant (n = 14), and 28.4% for central tumors (n = 88). IMC drainage rates differed significantly between upper and lower tumors (lower 36.4% vs. central 28.4% vs. upper 14.6%, P = 0.003) but not between medial and lateral tumors (medial 25.0% vs. central 28.4% vs. lateral 16.3%, P = 0.077).

CONCLUSIONS

Patients with tumors in the lower or central breast and positive axillary SLNs have increased incidence of drainage to the IMC. Preoperative lymphoscintigraphy can help to define the nodal basins at risk for harboring disease.

Preoperative Lymphoscintigraphy and Internal Mammary Sentinel Lymph Node Biopsy Do not Enhance the Accuracy of Lymphatic Mapping for Breast Cancer

Lymphoscintigraphy (LS) may identify sentinel lymph nodes (SLNs) outside the axilla. Biopsy of these nodes could improve the accuracy of lymphatic mapping (LM) for breast cancer (BC) if a significant number of tumor-positive extra-axillary sentinel nodes are identified. To address this, we evaluated the impact of the use of preoperative LS and biopsy of axillary and internal mammary SLNs in women with BC. From October 1997 to July 2003, 175 women with breast cancer received technetium sulfur colloid, and images were obtained. Isosulfan blue dye was injected intraoperatively, and LM of the axillary and internal mammary lymph node basins was performed with a hand-held gamma probe. The anatomic location and histologic status of all SLNs identified with LS and LM was recorded, and the impact of the findings on LS and internal mammary LM were evaluated. LS showed SLN in 127/175 (73%) women and “hot spots” were found with the gamma probe in 142/175 (81%). At least one SLN was identified by LM in 168/175 (96%) patients, and 48/168 (29%) had metastases. One hundred sixty-two of 168 (96%) patients had SLN exclusively in the axilla. Only 10 of 175 (6%) women had internal mammary (IM) SLNs seen on LS. LM identified IM sentinel nodes in 6 of these 10 patients, but none were involved with tumor. Preoperative lymphoscintigraphy and biopsy of internal mammary sentinel nodes do not enhance the accuracy of lymphatic mapping for breast cancer. Omitting lymphoscintigraphy reduces the complexity and cost of lymphatic mapping without compromising the identification of tumor-positive sentinel nodes.

Lymphatic mapping and sentinel lymphadenectomy for breast cancer

Lymphatic mapping and sentinel lymphadenectomy has become an important tool for axillary lymph node staging in women with early-stage breast cancer. This review examines data regarding the staging accuracy, indications and technical aspects of the procedure, and clinical trials investigating the technique. Multiple studies now confirm that sentinel lymphadenectomy accurately stages the axilla and is associated with less morbidity than axillary dissection. Blue dye, radiocolloid, or both can be used to identify the sentinel node, and several injection techniques may be used successfully. Many patient factors previously thought to affect accuracy of the procedure have now been shown to be of limited significance. The indications for the procedure are expanding, and the histopathologic evaluation of the sentinel node and the role of lymphoscintigraphy have been clarified. Clinical trials are now underway that will determine the prognostic significance of micrometastases and the therapeutic benefit of axillary dissection in women with and without sentinel node metastases. Incorporation of sentinel lymphadenectomy into routine clinical practice will maintain accurate axillary staging with lower morbidity and improved quality of life for women with early-stage breast cancer.

Technical Advances in Sentinel Lymph Node Biopsy for Breast Cancer

Technical advances in the past several years have simplified and improved sentinel lymph node (SLN) biopsy for breast cancer. The use of alternative injection sites (skin or subareolar) yields high SLN identification rates and may shorten the learning curve associated with standard peritumoral injection. The dual-agent (radiocolloid plus blue dye) technique is now recommended to decrease false-negative rates, especially when surgeons are just learning how to perform SLN biopsy. Methylene blue may be an acceptable substitute for isosulfan blue dye and is associated with fewer hypersensitivity reactions. Hand-held gamma probes are now smaller and more maneuverable, with better shielding for directional detection of gamma rays. Routine preoperative lymphoscintigraphy can be avoided, thus facilitating operating room scheduling. Surgeons can use minimally invasive techniques to identify and remove internal mammary SLNs.

Should decisions on internal mammary lymph node irradiation be based on current lymphoscintigraphy techniques for sentinel lymph node identification?

BACKGROUND

Treatment of internal mammary lymph node (IMN) metastases remains controversial because of the difficulty in predicting involvement, potential treatment-related morbidity, and questionable efficacy. Lymphoscintigraphy with sentinel lymph node biopsy offers a means to identify occult involvement of IMN, allowing appropriate patient selection for IMN treatment.

METHODS

The authors retrospectively reviewed 262 lymphoscintigraphies (LS) of 248 patients treated at the University of Florida (Gainesville, FL) between 1998 and 2002. Tumor characteristics were assessed for their value in predicting IMN drainage and their association with IMN radiation.

RESULTS

Lymph flow to the IMN was documented with LS in 23 of 262 tumor specimens (9%). Flow to the IMN was not correlated with any of the five factors: tumor location, tumor size, lymphovascular invasion, pathologic lymph node status, and laterality of the involved breast (right vs. left breast). Identification of IMN flow increased from 5.7% to 10.1% with the use of a deep injection technique. IMN radiotherapy was used more frequently in patients with larger tumors (15 of 188 in Tis/T1 vs. 31 of 70 in T2-T4; P<0.0001) and positive lymph nodes (17 of 91 in lymph node-negative patients vs. 28 of 66 in lymph node-positive patients; P<0.0001). In patients with T2N0 tumors (n=32), IMN radiotherapy was used more frequently with medial tumors (5 of 11 [45%]) than with lateral tumors (4 of 21 [19%]).

CONCLUSIONS

The incidence of flow to the IMN documented with the current LS technique was low compared with other LS and extended radical mastectomy series. Histopathologic information was obtained for the sentinel IMN when IMN flow was identified on the LS. In the absence of histopathologic information, treatment decisions should continue to be based on clinical factors known to be correlated with occult IMN involvement.

[Preoperative lymphoscintigraphy to identify the sentinel lymph node in breast cancer]

INTRODUCTION

The preoperative lymphoscintigraphy to the Sentinel Node Biopsy (SNB) can reproduce the lymphatic drainage of the tumour in breast cancer.

OBJECTIVES

To establish the pattern of lymphatic drainage of the mammary tumors by means of isotopic lymphoscintigraphy and determine the factors that could influence the negativity of the scintigraphy.

METHODS

121 patients with breast cancer who were going to undergo mammary surgery were studied with SNB. One day before the operation, 37 MBq 99mTc-colloidal sulphide colloid in a volume of 2 ml was injected in peritumoral tissue. Mammary lymphoscintigraphies were performed at 30 minutes and 18 hours P.I., in ANT and OA projections of the corresponding chest. After, the clinical-biological parameters and their influence on the result of the lymphoscintigraphy were analyzed.

RESULTS

The scintigraphy were positive in 85 % of the patients. The axillary chain was observed in 97 % and the internal mammary chain in 11 %. The factors associated to the absence of visualization of the sentinel node were: older than 50 years (94 %), menopause (89 %), tumoral size > or = 2 cm (67 %), axillary metastases (67 %), the overexpression of C-erbB-2 oncoprotein (44 %) and proliferative activity > 10 % (67 %).

CONCLUSIONS

The peritumoral injection of the radiocolloid establishes the lymphatic drainage pattern in the patients with breast cancer. Its absence of visualization can be associated to circumstances like: age > or = 50 years, menopause, tumoral size > or = 2 cm, axillary metastases, tumoral overexpression of the C-erbB-2 oncoprotein and high proliferative activity of the mammary tumor.