The FDA has approved the first molecular-based laboratory test designed to detect whether breast cancer has spread (metastasized) to nearby lymph nodes. The GeneSearch Breast Lymph Node (BLN) Assay detects molecules that are abundant in breast tissue but scarce in a normal lymph node, the agency said.

The GeneSearch BLN Assay from Veridex (Warren, New Jersey), a Johnson & Johnson (New Brunswick, New Jersey) company, is designed to detect the spread of cancer into the lymph nodes more accurately than existing rapid methodologies and, as a result, has the potential to reduce the need for stressful and costly second surgeries for breast cancer patients, according to Veridex.

"It's always great to be the first to market with a test like this ... we're very excited," Steve Dnistrian, a company spokesman, told Diagnostics & Imaging Week. "It's all about improving the standard of care for breast cancer patients. As of Monday, there is a brand new tool in the arsenal that doctors can now turn to to fight breast cancer."

The GeneSearch BLN Assay is the first in vitro diagnostic test approved in the U.S. for the rapid detection of metastases greater than 0.2 mm in sentinel lymph node tissue removed from breast cancer patients, Veridex said.

The presence or absence of breast cancer cells in underarm lymph nodes is a powerful predictor of whether the cancer has spread and is used to help decide appropriate therapy for a woman with metastatic breast cancer, according to the FDA.

Lymph nodes are part of the system that helps protect the body against infection. The first lymph node that filters fluid from the breast is called the sentinel node, because that is where breast cancer cells are likely to spread first, the agency said.

During a lumpectomy or mastectomy to remove a breast tumor, surgeons commonly remove the sentinel node for examination under a microscope. Sometimes the sentinel node is examined immediately and if tumor cells are found, additional lymph nodes are removed. A more extensive microscopic examination, requiring one to two days for results, is almost always performed. If tumor cells are only found with the later microscopic examination, the patient may require a second surgery to remove the remaining lymph nodes.

"The question for the patient and the physician during that initial operation is 'has the cancer spread?' And this test is designed to answer that question and offer assurance, accuracy and confidence ..." Dnistrian said. "[Physicians] want to know for certain, at that moment, 'is it in the lymph nodes or not? It is a break through."

In a clinical trial, the GeneSearch BLN Assay showed strong agreement with results from extensive microscopic examination of the lymph nodes of 416 patients, the FDA said. According to the agency, the test accurately predicted that breast cancer had spread nearly 88% of the time in women with metastasis and patients without metastasis were identified accurately 94% of the time.

The new, gene-based technology of the GeneSearch test allows for the analysis of 50% of the sentinel node, versus 5% of tissue typically examined under a microscope for evidence of cancer cells. Test results from GeneSearch can be produced in 35 to 40 minutes during the initial surgical procedure versus two to three days with tissue pathology, Veridex said.

"The GeneSearch BLN Assay offers a new approach to sentinel node testing," said Daniel Schultz, MD, director of the FDA's Center for Devices and Radiological Health. "Results of this rapid test are available while patients are on the operating table, providing a way for some women to avoid a second operation."

Most of the women were also studied to compare the BLN Assay with immediate microscopic examination during surgery. According to the FDA, the test gave fewer false negative results, but slightly more false positive results. A false negative test result, when the cancer has actually spread, may delay the needed removal of additional lymph nodes. A false positive test, indicating metastasis when there is none, may result in a more extensive surgery and puts the women at risk of unnecessary lymphedema (swelling due to fluid build-up following lymph node removal) and other side effects.

"There is no perfect test out there but this is just another step forward ... science and medicine continue to take steps forward that gets us to a better place in terms of having a correct diagnoses," Dnistrian said.

The GeneSearch BLN Assay is the first in vitro diagnostic test approved in the U.S. for the rapid detection of metastases greater than 0.2 mm in sentinel lymph node tissue removed from breast cancer patients, Veridex said.

Given its level of accuracy, Veridex said, GeneSearch has the potential to prevent the need for costly and traumatic second surgeries for as many as 5,200 additional breast cancer patients in the U.S. each year.

"Reducing costs, sparing patients from second surgeries, is just profound," Dnistrian said. "[Physicians say] there's nothing worse than having to call a patient back for a second surgery after they've just been through one."

The GeneSearch BLN Assay, which can be performed by trained laboratory technicians, is also available in Europe. In the coming months and years, Veridex said it would expand the GeneSearch product platform with additional gene-based diagnostic, confirmatory, and prognostic oncology tests for breast and other cancers.

"There is a need for a more accurate test to detect metastasized breast cancer in a woman's lymphatic tissue — and that's where the GeneSearch BLN Assay comes in," said Ken Berlin, general manager, Veridex. "We now have the opportunity to detect some metastases that could be missed by other tests. The end result is better patient management and better patient standard-of-care."

Veridex said it would initiate two post-approval studies on the GeneSearch BLN Assay. The first study will further substantiate the turnaround time of the test when used intra-operatively, the company said. An additional study, which will involve more than 1,000 patients, will further validate the accuracy of GeneSearch BLN.

"We'll need to do some very thoughtful post-approval studies," Dnistrian said. "We want to make sure we are getting the best and most accurate test results possible."