The Boston Globe, July 17, 2007
US approves gene test for breast cancer ; It can tell in minutes if illness has spread, requires more surgery
Diedtra Henderson
Globe Staff
© 2007 New York Times Company. Provided by ProQuest Information and Learning. All Rights Reserved.
WASHINGTON - Federal regulators yesterday approved the first molecular-based laboratory test that - within minutes - can tell surgeons whether breast cancer has spread and requires more intensive surgery.
Some 1.2 million American women each year undergo breast biopsies, medical procedures that, for 200,000 of those women, result in a diagnosis of breast cancer. For most women, the scope of treatment depends on the health of their lymph nodes, which are located near the breast and can be a powerful predictor of whether the cancer has spread.
The Food and Drug Administration's approval of the GeneSearch Breast Lymph Node Assay, a diagnostic test marketed by Johnson & Johnson subsidiary Veridex, could allow more women to get diagnosed faster. Using conventional techniques, right now 44,400 women a year find out during their initial surgery that more extensive surgery is needed. The GeneSearch could increase that number by 5,200, but that figure could grow if it can prove its accuracy in a larger group of women.
The testing method "offers a new approach," said Dr. Daniel Schultz, 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."
The test focuses on the lymph node most likely to contain cancerous cells. That so-called "sentinel" node is removed by surgeons and is analyzed. If it is cancer-free, no additional lymph nodes are removed. If that "sentinel" node contains cancer cells, however, surgeons frequently remove additional lymph nodes, which protect the body against infection.
Veridex's GeneSearch assay can shrink the wait for test results on those lymph nodes from days to about 40 minutes, and that waiting would occur as the woman remains anesthetized during the initial surgery. The test quickly measures the presence and concentration of genes that, normally, should not be present in the lymph node and are highly correlated with breast cancer.
The diagnostic, expected to cost roughly $200, is the newest in about a dozen such tests that the FDA has approved to leverage the power of genetics to improve and personalize healthcare.
"It's the beginning of a new era," said Dr. Pat Whitworth, director of the Nashville Breast Center and a principal investigator in the clinical trials that underpinned FDA approval.
The test differs from other genetic approaches that, after a flurry of initial hype, failed to truly revolutionize care, Whitworth said.
"This is really a feet-on-the-ground" tool, he said. "This is a little different, in the sense that it is a diagnostic, and it really does give us another level of detail."
Cutting the wait time can reduce anxiety for patients.
"You've just been through surgery. You've had a change in your breast," said Dr. Mehra Golshan, a breast cancer researcher at Brigham and Women's. "It's a very traumatic time - physically and emotionally - to say `You have to come back."'
Golshan said it would be great to spare women the trauma of having to return for a second operation, but he worries the GeneSearch test carries a higher rate of false positives - finding cancer when it's not really there - than the sleuthing method that it ultimately seeks to replace.
In clinical trials involving 416 patients, the test accurately predicted breast cancer had spread 88 percent of the time, according to the FDA. The test accurately determined breast cancer had not spread 94 percent of the time. A false positive could subject some women to unneeded surgery and such side effects as swelling.
Veridex pledged to conduct two studies after yesterday's decision to confirm the test can reliably report results in 35 to 40 minutes and, in a study involving 1,000 patients, confirm its accuracy.
Diedtra Henderson can be reached at dhenderson@globe.com.