A Diagnostics & Imaging Week

Results from a prospective clinical study indicate that the GeneSearch Breast Lymph Node (BLN) Assay, a gene-based diagnostic test from Veridex (Warren, New Jersey), has greater sensitivity than traditional intra-operative methods of detecting the spread of breast cancer to the lymph nodes.

In the Veridex-sponsored study, GeneSearch BLN Assay demonstrated overall sensitivity at least 10 percentage points higher than traditional intra-operative tests. The data were presented Saturday at the 29th Annual San Antonio Breast Cancer Symposium that concluded Sunday in Texas.

"These results indicate the potential advantage of the GeneSearch BLN Assay as an objective, standardized test that can assess breast cancer metastasis in the lymph nodes rapidly and with greater overall sensitivity than the current standard of care," said study investigator Peter Blumencranz, MD, medical director of Comprehensive Breast Health and Cancer Services, Morton Plant Mease Healthcare, and medical director of Moffitt Morton Plant Cancer Care (both Clearwater, Florida). "This intra-operative test may provide surgeons with critical information that can help them optimize treatment decisions by allowing them to determine the scope of the surgery required."

In the study involving 416 evaluable patients across 11 clinical sites, sentinel lymph nodes were tested using the GeneSearch BLN Assay and current methods for assessing nodal tissue during surgery (frozen section [FS] or touch preparations [TP]). All nodes were sampled for permanent section hematoxylin/eosin (H&E), and most were also sampled for immunohistochemistry (IHC). The GeneSearch BLN Assay, FS and TP results were each compared to permanent section histology results to determine the performance of each method.

The test was evaluated in terms of sensitivity and specificity, which measure how well the method correctly identifies nodes with and without clinically relevant metastases.

In head-to-head comparison with FS, overall sensitivity of the GeneSearch BLN Assay was 95.6% —10 percentage points greater than the overall sensitivity of FS (85.6%).

In the same patient comparison, overall specificity of the GeneSearch BLN Assay remained high, with a value of 94.3% compared to the 97.8% overall specificity of FS. In comparisons with TP, overall sensitivity of the GeneSearch BLN Assay was 18 percentage points greater than the overall sensitivity of TP. In the same patient comparison, overall specificity of the GeneSearch BLN Assay remained at 100% for both the assay and TP.

The test "has the potential to improve intra-operative pathology and surgical decision-making, reduce the need for second surgeries, and thereby significantly improve patient care," said Mark Myslinski, general manager of Veridex.

Sentinel lymph node biopsy (SLNB) is a widely used procedure in the management of breast cancer. SLNB involves removing the first (sentinel) lymph node that filters fluid from the breast, as this node is the most likely to contain cancer cells if the cancer has begun to spread. If there is no evidence of metastases in the sentinel node, it is unlikely that the cancer has spread to other nodes, and there may be no need for further surgery.

Results of the GeneSearch BLN Assay can typically be reported during the operation in 30 to 40 minutes from the time the sentinel node is removed. The test outcomes are intended to be used to guide the decision to excise additional lymph nodes and to aid in patient staging.

The GeneSearch BLN Assay is CE-marked.

Veridex is a Johnson & Johnson (New Brunswick, New Jersey) company that develops cancer diagnostics designed to enable earlier detection as well as more accurate staging, monitoring and therapeutic selection.

The company is developing two complementary product lines: CellSearch assays that identify and characterize circulating tumor cells directly from whole blood; and GeneSearch assays that use molecular technology to diagnose, stage and more accurately characterize tumors.

In other reports from the symposium:

• Quest Diagnostics (Lyndhurst, New Jersey) said that clinicians will have a new prognostic tool in the battle against breast cancer with its introduction of its test, the Breast Cancer Gene Expression Ratio, designed to help physicians predict the risk of disease recurrence in women with estrogen receptor-positive, lymph node-negative breast cancer. Quest said it is the first company to develop a breast cancer recurrence test based on licensed gene-expression profiling technology from AviaraDx (Carlsbad, California), a molecular cancer profiling company.

The Breast Cancer Gene Expression Ratio is based on the ratio of the expression of two genes: the homeobox gene-B13 (HOXB13) and the interleukin-17B receptor gene (IL17BR). In breast cancers that are more likely to recur, the HOXB13 gene tends to be over-expressed, while the IL-17BR gene tends to be under-expressed.

In an 852-patient retrospective study published recently in the Journal of Clinical Oncology, researchers found that the HOXB13:IL17BR ratio independently predicted breast cancer recurrence in patients with ER-positive, lymph-node negative cancer. The H:I expression ratio was found to be predictive in patients who received tamoxifen therapy as well as in those who did not.

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