[RobinP]

<table border="0" cellpadding="0" cellspacing="3" width="98%"><tbody><tr><td nowrap="nowrap" valign="top" width="1%">Abstract No:

</td> <td valign="top" width="99%"> 10507

</td> </tr> <tr> <td nowrap="nowrap" valign="top" width="1%">Citation:

</td> <td valign="top" width="99%"> Journal of Clinical Oncology, 2006 ASCO Annual Meeting Proceedings Part I. Vol 24, No. 18S (June 20 Supplement), 2006: 10507

</td> </tr> <tr> <td nowrap="nowrap" valign="top" width="1%">Author(s):

</td> <td valign="top" width="99%"> P. Meijnen, M. C. Van Rijk, H. S. Oldenburg, C. E. Loo, R. A. Valdés Olmos, O. E. Nieweg, J. L. Peterse, M. J. Van de Vijver, E. J. Rutgers

</td> </tr> <tr> <td nowrap="nowrap" valign="top" width="1%">Abstract:

</td> <td valign="top" width="99%"> Background: About 20% of ductal carcinoma in situ (DCIS) lesions diagnosed by stereotactic core needle biopsy (SCNB) are shown to be invasive on postoperative pathology examination. Sentinel lymph node biopsy (SLNB) is an accurate method of evaluating axillary lymph nodes in patients with invasive breast cancer. The aim of this study was to review our experience with lymphatic mapping in patients with a SCNB diagnosis of pure DCIS, to evaluate the DCIS underestimation rate and consequently the risk of lymph node metastases. Methods: Files from 160 patients diagnosed with pure DCIS by SCNB between July 1999 and March 2005 were retrieved from our database. Patients with DCIS were selected for SLNB if there was concern for presence of an invasive component on the basis of size, palpability or imaging. Results: The median age of the study group was 55 years (range 29-85 years) and median DCIS size on mammography was 25 mm (range 4-96 mm). Thirty-six (23%) out of the 160 women underwent a SLNB. Macrometastases in the sentinel node were detected in seven (19%) patients and one (3%) patient was found to have a micrometastasis. Twenty (56%) of these 36 patients had invasive lesions on final pathology. Of the 124 women who did not receive SLNB, 29 (24%) turned out to have invasive lesions on postoperative evaluation. In total, 49/160 (31%) patients with pure DCIS diagnosed by SCNB had invasive breast cancer (range pT1mic-pT2) on final pathology. Finally, 88 patients underwent lymphatic staging by SLNB, basal node sampling or complete axillary lymph node dissection. Nodal involvement was present in 14 (16%) out of these 88 patients with initially diagnosed DCIS: 36% in patients with invasive breast cancer and 2% with pure DCIS on final pathology. Conclusion: Postoperative pathology examination of the specimen demonstrates DCIS underestimation in nearly one third of SCNB diagnosed DCIS patients. SLNB is of benefit for these patients as in 19% of the patients who undergo a SLNB macrometastatic disease in the sentinel node can be found.


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[P-3] Micrometastases in the sentinel node: take it or leave it?

According to this abstract, the primary tumor is of more importance than sentinel, though other medical opinions may vary...

Rutgers EJ.. The Netherlands Cancer Institute, Amsterdam, Netherlands

Early knowledge of nodal involvement in invasive breast cancer is thought to be valuable. In overt nodal involvement, so called macrometastatic disease, there is little discussion about the implications for prognosis and treatment. Its associated poor prognosis will always indicate adjuvant systemic and regional treatments: usually chemo- and endocrine therapy, complete axillary clearance, on indication followed by radiotherapy. The sentinel node (SN) procedure is a very reliable method of assessing axillary lymph node involvement in clinically node negative breast cancer and should be considered as standard of care. SN are now examined with great thoroughness and many protocols for this exist. The result is the frequent finding of the so called micrometastasis. What are the issues at stake?
The definition. Micrometastasis is defined as metastasis < 2mm in diameter and sub-micrometastasis or clusters of isolated tumour cells(ITC) < 0.2 mm in size. Micrometastases are found in about 30% of all tumour positive sentinel nodes.
The type of examination. One may add, over H-E staining, multiple slicing of the SN, staining with immunohistochemistry (IHC) or RT-PCR techniques with breast cancer related probes. Each step will lead to an 10% increase in finding small clusters of epithelial -cancer?- cells or RNA traces assumed to represent cancer cells. But are these cells viable, able to produce offspring and endanger the patient if left in situ? Or are this just innocent displaced cells. We performed an analysis of over 9000 published patients in whom the axilla was left untreated after a negative SN: after an average of 3 years of follow up, the clinical occurrence of metastasis was 0.4%, whilst the false negative rate after back up ALND in SN negative patients varies from 2-11%.
Predictor of non-SN involvement. This risk increases with tumor size, size and number of SN metastasis. In only ITC/sub-micrometastasis this risk is less then 10% where the involved non-SN frequently are macrometastatic as well.
The prognostic value. A number of studies suggest that such micrometastasis does not independently influence survival prognosis, if compared to tumour size and grade. So missing one micrometastasis by omitting multiple slicing and IHC would have hardly any influence in terms of prognostic information. Furthermore, many patients would have adjuvant systemic treatment based on primary tumour characteristics, which may be of much stronger prognostic value than nodal status.
In conclusion, one should not to look too hard for micrometastasis in the sentinel node. Effort in ascertaining the clinical relevance of such micrometastasis is surely the province of research, not for routine clinical practice. If micrometastasis (0.2 - 2.0 mm)are found, further axillary treatment (ALND if indication for adjuvant systemic treatments is uncertain) is warranted. If other nodes are negative or only micrometastatic, adjuvant treatment should only be based on primary tumor characteristics. In general, sub-micrometastasis (< 0.2 mm) or ITC can be ignored.

Saturday, December 16, 2006 9:00 AM

Plenary Lecture 3 (9:00 AM-9:30 AM)


<table with="95%" align="center" border="0" cellpadding="4" cellspacing="4"><tbody><tr><td>[21] Significance of sentinel lymph node micrometastasis on survival for patients with invasive breast cancer.

Cox C, Vrcel V, Riker A, White L, Allred N, Ramos D, Myers M, Dupont E, King J, Cantor A, Diaz N. H. Lee Moffitt Cancer Center, Tampa, FL

OBJECTIVE: The overall objective of this study was to test the impact of micrometastatic carcinoma detected by sentinel lymph node (SLN) biopsy on survival in invasive breast cancer patients. To do so, we compared survival outcomes in such patients with a negative SLN biopsy and the outcomes of those with micrometastatic disease in a SLN.
METHODS: The charts of 2145 invasive breast cancer patients with pathology reports of SLN with either micrometastatic or no metastatic disease were reviewed. The SLN HE and immunostained (cytokeratin) slides of patients with the diagnosis of micrometastatic carcinoma were analyzed and reclassified according to the 6^th edition of the AJCC Cancer Staging Manual. Tumor deposits > 0.2 mm but not > 2 mm were classified as N1mi. Patients with SLNs with isolated tumor cells not > 0.2 mm were classified as N0(i+). SLNs with no epithelial cells on either HE or immunostaining were classified as N0(i-). Kaplan Meier graphs of overall survival (OS) and disease free survival (DFS) were done.
RESULTS: Of the 2145 patients reviewed, 1854 (87%) were N0(i-). 291(13%) of our patients had single cells and/or small cell clusters or micrometastatic disease. 138 (6%) were reclassified as N1mi and 153 (7%) as N0(i+). OS and DFS of the patients with N1mi SLN differed significantly from patients with N0(i-) SLN (p=0.005 and 0.016 respectively; Figures 1 and 2).
CONCLUSIONS: The detection of micrometastatic carcinoma in the SLNs of invasive breast cancer patients, as presently defined by the AJCC, is a significant indicator of survival. Subset analysis of N0(i+) patients will be presented. Results of the ACOSOG Z0010 trial may validate the latter results and clarify the clinical significance of N0(i+) detected by SLN biopsy.





Friday, December 9, 2005 2:15 PM

General Session 4 (2:00 PM-3:30 PM)

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