Axillary Lymph Node Nanometastases Are Prognostic Factors for Disease-Free Survival and Metastatic Relapse in Breast Cancer Patients

Lymphovascular invasion and lobular histology are associated with increased incidence of isolated tumor cells in sentinel lymph nodes from early-stage breast cancer patients

BACKGROUND

Isolated tumor cells (ITC) are more likely to be identified when serial sectioning and immunohistochemical staining are used to evaluate sentinel lymph nodes (SLN). Our goal was to identify clinicopathologic features associated with ITC in patients undergoing sentinel lymph node dissection (SLND).

METHODS

We reviewed clinicopathologic data for 3557 patients with no clinical evidence of lymph node metastases undergoing SLND between November 1993 and March 2007. Patients were staged according to the 6th edition of the American Joint Committee on Cancer staging system, with metastasis <or=.2 mm classified as ITC.

RESULTS

A SLN was identified in 3475 patients (97.7%), including 2518 (72.4%) with negative nodes and 169 (4.9%) with ITC. A statistically significant association existed between lobular histology and the identification of ITC; 13.6% of patients with ITC had lobular histology versus 7.3% of patients with a negative SLN (P = .003). The presence of lymphovascular invasion (LVI) was also associated with ITC; 18.3% of patients with ITC had LVI in the primary tumor versus 8.5% of patients with a negative SLN (P < .001). No difference existed between patients with and without ITC with respect to T stage, grade, estrogen receptor, progesterone receptor, HER2/neu status, or biopsy method.

CONCLUSION

The association between ITC and LVI, a known predictor of poor outcome, suggests ITC may have clinical relevance. The relationship between lobular histology and ITC is consistent with the known pattern of lobular metastases, which frequently present as small foci requiring immunohistochemistry for detection. Longer follow-up is needed to determine whether ITC have prognostic significance.

Minimal disease in sentinel nodes

Isolated tumor cells and micrometastases represent low-volume or minimal disease in the regional lymph nodes of breast cancer patients as compared to macrometastases. Sentinel lymph node biopsy is a functional selection and removal of the most likely site of regional metastasis, and gives pathologists the opportunity to concentrate detection techniques on a limited number of lymph nodes. Consequently, more lesions belonging in the two mentioned staging categories are discovered in sentinel lymph nodes. Despite some publications contradicting stochastic models of breast cancer, micrometastases seem to reflect a prognosis intermediate between the node-negative and macrometastatic nodal status, and they also reflect a risk of non-sentinel node involvement slightly higher than that associated with a node-negative status. Data are more contradictory as concerns isolated tumor cells. This minireview summarizes the definitions, their inconsistencies, pathological protocols aiming at the detection of minimal nodal disease, the prognostic impact and non-sentinel node involvement related risk of such nodal lesions, and their therapeutic consequences.

Imaging of lymph flow in breast cancer patients after microdose administration of a near-infrared fluorophore: feasibility study

PURPOSE

To prospectively demonstrate the feasibility of using indocyanine green, a near-infrared (NIR) fluorophore at the minimum dose needed for noninvasive optical imaging of lymph nodes (LNs) in breast cancer patients undergoing sentinel lymph node mapping (SLNM).

MATERIALS AND METHODS

Informed consent was obtained from 24 women (age range, 30-85 years) who received intradermal subcutaneous injections of 0.31-100 microg indocyanine green in the breast in this IRB-approved, HIPAA-compliant, dose escalation study to find the minimum microdose for imaging. The breast, axilla, and sternum were illuminated with NIR light and the fluorescence generated in the tissue was collected with an NIR-sensitive intensified charged-coupled device. Lymphoscintigraphy was also performed. Resected LNs were evaluated for the presence of radioactivity, blue dye accumulation, and fluorescence. The associations between the resected LNs that were fluorescent and (a) the time elapsed between NIR fluorophore administration and resection and (b) the dosage of NIR fluorophores were tested with the Spearman rank and Pearson product moment correlation tests, respectively.

RESULTS

Lymph imaging consistently failed with indocyanine green microdosages between 0.31 and 0.77 microg. When indocyanine green dosages were 10 microg or higher, lymph drainage pathways from the injection site to LNs were imaged in eight of nine women; lymph propulsion was observed in seven of those eight. When propulsion in the breast and axilla regions was present, the mean apparent velocities ranged from 0.08 to 0.32 cm/sec, the time elapsed between "packets" of propelled fluid varied from 14 to 92 seconds. In patients who received 10 microg of indocyanine green or more, a weak negative correlation between the fluorescence status of resected LNs and the time between NIR fluorophore administration and LN resection was found. No statistical association was found between the fluorescence status of resected LNs and the dose of NIR fluorophore.

CONCLUSION

NIR fluorescence imaging of lymph function and LNs is feasible in humans at microdoses that would be needed for future molecular imaging of cancer-positive LNs.

Lymphatic metastasis in breast cancer: importance and new insights into cellular and molecular mechanisms

Lymph node metastasis is the main prognosis factor in a number of malignancies, including breast carcinomas. The means by which lymph node metastases arise is not fully understood, and many questions remain about their importance in the further spread of breast cancer. Nevertheless, a number of key cellular and molecular mechanisms of lymphatic metastasis have been identified. These include induction of intra- or peri-tumoral lymphangiogenesis or co-option of existing lymphatic vessels to allow tumour cells to enter the lymphatics, although it remains to be established whether this is primarily an active or passive process. Gene expression microarrays and functional studies in vitro and in vivo, together with detailed clinical observations have identified a number of molecules that can play a role in the genesis of lymph node metastases. These include the well-recognised lymphangiogenic cytokines VEGF-C and VEGF-D as well as chemokine-receptor interactions, integrins and downstream signalling pathways. This paper briefly reviews current clinical and experimental evidence for the underlying mechanisms and significance of lymphatic metastasis in breast cancer and highlights questions that still need to be addressed.

Sentinel node staging for breast cancer: intraoperative molecular pathology overcomes conventional histologic sampling errors

BACKGROUND

When sentinel node dissection reveals breast cancer metastasis, completion axillary lymph node dissection is ideally performed during the same operation. Intraoperative histologic techniques have low and variable sensitivity. A new intraoperative molecular assay (GeneSearch BLN Assay; Veridex, LLC, Warren, NJ) was evaluated to determine its efficiency in identifying significant sentinel lymph node metastases (>.2 mm).

METHODS

Positive or negative BLN Assay results generated from fresh 2-mm node slabs were compared with results from conventional histologic evaluation of adjacent fixed tissue slabs.

RESULTS

In a prospective study of 416 patients at 11 clinical sites, the assay detected 98% of metastases >2 mm and 88% of metastasis greater >.2 mm, results superior to frozen section. Micrometastases were less frequently detected (57%) and assay positive results in nodes found negative by histology were rare (4%).

CONCLUSIONS

The BLN Assay is properly calibrated for use as a stand alone intraoperative molecular test.

[Sentinel node biopsy in invasive breast cancer in 2007]

Sentinel lymph node (SN) biopsy for breast cancer has been introduced in the mid-1990s and it has now been performed on thousands of patients. This procedure has been rapidly adopted around the world by surgical specialists in clinical practice as a diagnostic procedure instead of the axillary lymph node dissection. The diffusion of the SN mapping in routine must be careful by respecting some principles of methodology and especially of training, in order to maintain its irreversible development. However, the advent of this mini-invasive technique revealed new questions, which the concept of the SN procedure raises: can we increase the current indications? Could axillary lymph node dissection be avoided in patients with metastatic SN? What is the morbidity of the biopsy of the SN? Which is the prognostic value of micrometastatis discovered by the diffusion of the ultra-stadification of the SNs? The GS procedure is a diagnostic method the reliability of which is now on accepted in its usual indications (tumours in place, small size breast tumour without palpable adenopathy). The value of the axillary dissection after metastatic SN is the subject of debates and controversies although axillary dissection remains recommended. So the use of scores or predictive nomograms is currently developed to select the patients being able not to justify of complementary axillary dissection, and seems promising.

Standardizing Slide-Based Assays in Breast Cancer: Hormone Receptors, HER2, and Sentinel Lymph Nodes

Despite the rapid expansion of novel diagnostics designed to personalize breast cancer care, there remain several significant unmet needs for improving the accuracy and reliability of tests that are already in common daily clinical practice. For example, although immunohistochemistry has been the predominant method for measuring estrogen receptor and progesterone receptor status for over 15 years, this assay remains unstandardized and there is a widespread concern that inaccuracy in immunohistochemistry technique and interpretation is leading to an unacceptably high error rate in determining the true hormone receptor status. Similarly, there is considerable concern that both false-negative and false-positive result rates for testing for HER2 status are unacceptably high in current clinical practice. This commentary considers a variety of factors, including preanalytic conditions and slide-scoring procedures, and other variables that may be contributing to current testing error rates and why there is a great need for the standardization of these biomarker assay procedures to further enable the highest possible quality of care for newly diagnosed breast cancer patients.