Biopsy of this "sentinel" node occurs after the tumor has been removed in an initial surgery, and if metastasis is found there, surgeons continue to sample "downstream" nodes to check for degree of spread. While this procedure, called "sentinel node biopsy" is now practiced routinely in the U.S. and in many other countries, there remains controversy in the accurate assessment of micrometastasis in sentinel lymph nodes, according to Hoon. He said recent studies have found that it can produce both false positive and false negative results.
Furthermore, microdisease seen in the sentinel lymph node doesnt always predict that a patient will go on to develop metastatic breast cancer, said Hoon. "If the primary tumor and nodes are removed in some women, they will not develop recurrent disease, but in other women, removal of the nodes may have no impact on the spread of the metastatic disease that has already occurred prior to surgery."
In this study, 65 patients with invasive cancer who underwent surgery and biopsy of the sentinel lymph node and/or other lymph nodes were enrolled, and investigators were blinded as to the findings of these lymph node biopsies.
In all, 24 patients (37 percent) were found to have cancer in their nodes and 41 patients (63 percent) were node negative. To predict lymph node metastasis, the investigators used a ProteinChip to identify biomarkers that distinguished between the tumor profile with paired positive and negative nodes.
Two protein peaks associated with lymph node metastasis were identified. Specifically, over-expression of protein peaks at 4,871 Da (which represents the molecular weight of the protein) and under-expression of a protein peak at 8,596 Da were highly predictive of lymph node metastasis.
Patients with two or more positive lymph nodes were significantly more likely to
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Contact: Staci Vernick Goldberg
goldberg@aacr.org
215-440-9300
American Association for Cancer Research
15-Dec-2006