New Test Improves Breast Cancer Detection

Dec. 16, 2007 — -- A new molecular assay test improves the accuracy of finding cancer in the lymph nodes during a sentinel lymph node biopsy, according to results presented by researchers Saturday at the San Antonio Breast Cancer Symposium.

Results of the study showed that the GeneSearch BLN Assay test, developed by Veridex LLC and approved by the FDA in mid-July, is about 10 percent more sensitive than traditional histology and microscopic exams in finding evidence of tumor cells during a sentinel lymph node biopsy.

One of the challenges of the sentinel lymph node biopsy is that a pathologic examination of the lymph nodes must be done during a halt in the surgery to assess whether there is a tumor in the sentinel nodes. Traditionally, surgeons conduct a sentinel lymph node biopsy by removing less than 5 percent of the lymph node during an intra-operative halt in the surgery. The small node section is then frozen and examined under a microscope for the presence of cancer cells. If cancer cells are found in the nodes, the surgeon will typically remove these lymph nodes during the biopsy procedure.

However, all too often the results of this assessment are inaccurate, requiring the patient to undergo the physical and emotional stress of returning to the operating room for yet another surgical procedure to remove the cancerous lymph nodes.

The GeneSearch molecular assay test, which the FDA approved as a replacement for the standard frozen section method of examining the sentinel lymph nodes during a biopsy, is an ultra-rapid method of doing a genetic screening test to look for evidence of tumor cells in the lymph nodes during the intra-operative halt in the surgery. Researchers reported that this new technique is more sensitive than frozen section, without sacrificing specificity.

Researchers did both standard frozen section and molecular assay tests on 319 breast cancer patients. The pathologists who did the frozen section did not know the results of molecular assay test, and vice versa. After both diagnostic tests were completed, researchers compared the results from each test to the final pathologic report on each patient.