A test that quickly detects cancer cells in a lymph node during surgery to remove breast cancer is accurate enough to help doctors decide if lymph nodes need to be removed during the surgery.
During surgery to remove early-stage breast cancer, the lymph node closest to the cancer -- called the sentinel node -- often is removed and sent to a pathologist for evaluation. Removing just this one node is called a sentinel node dissection. Doctors remove one or more lymph nodes when removing the breast cancer to see if any cancer cells that can't be seen by the human eye are in the lymph node.
Ideally, a surgeon would know if cancer cells are in the sentinel node before the surgery to remove the breast cancer is finished. That way if any more lymph nodes need to be removed, it could be done during that one surgery. Unfortunately, accurately analyzing lymph node tissue using traditional methods takes about a week. So if cancer cells are detected in the sentinel node, a second surgery must be done.
The study reviewed here evaluated a test that uses PCR (polymerase chain reaction) to determine if breast cancer cells are in the sentinel node. The test, developed by Veridex, LLC, is called GeneSearch Breast Lymph Node Assay and has been approved by the FDA.
The results of the GeneSearch test are usually available in about 35 minutes. Having lymph node analysis done this quickly would allow the surgeon to remove the breast cancer while waiting for the results of the lymph node test. If cancer is detected in the lymph node, the surgeon could then remove more lymph nodes during the same operation.
This study looked at GeneSearch test results from more than 1,100 women in the United States, the United Kingdom, and Belgium. The researchers compared the GeneSearch test results with results from traditional lymph node analysis by a pathologist. The GeneSearch test was very accurate. When the GeneSearch test result was negative, the pathologist's lymph node report also detected no cancer 96% of the time.
It's important to know that while very reliable, the GeneSearch test ISN'T a replacement for having a pathologist examine any removed lymph nodes. Still, the test could help some women avoid a second operation by determining if more lymph nodes needed to be removed during initial breast cancer surgery. The GeneSearch test also could offer a second set of reassuring results to anyone whose pathology report shows no cancer in the lymph nodes.
Stay tuned to Breastcancer.org for the latest news on research that may lead to better ways to prevent, diagnose, and treat breast cancer. And visit the Breastcancer.org Lymph Node Removal pages to learn more about the different procedures to remove lymph nodes.
TORONTO, May 8 (MedPage Today) -- A rapid molecular test for breast cancer micro-metastases in the sentinel lymph node can reduce the need for additional lymph node surgery, an international team of researchers said.
The test -- marketed by Veridex LLC of North Raritan, NJ -- takes about 35 minutes to produce results and can be done while the primary tumor is being removed, according to Denis Larsimont, M.D., Ph.D., of the Jules Bordet Institute in Brussels, and colleagues.
Typically, surgeons remove the sentinel node and test it for micro-metastases after the tumor resection is over, Dr. Larsimont said at the first IMPAKT Breast Cancer Conference.
Then, if the node contains tumor cells, a woman must undergo a second operation for a complete axillary lymph node dissection, he said.
In contrast, if the molecular test is positive, surgeons can perform the axillary node dissection immediately after tumor removal -- eliminating the need for additional surgery.
The key finding of the study, Dr. Larsimont said, is that if the test is negative, it's highly unlikely that the cancer has spread to the other nodes.
For the study, the test was used during breast cancer surgery on 1,138 women in four U.S. sites and one each in Belgium and the United Kingdom. The researchers compared results of the molecular test with what was seen using traditional permanent section histology.
Analysis showed that traditional histology had a negative predictive value of 90%, compared with 96% for the new test, Dr. Larsimont reported.
When the two methods were combined, the negative predictive value was 99%.
Of the 1,138 patients, only 18 -- or 1.6% -- had a negative result on the molecular test but a positive result on the histology, Dr. Larsimont said.
"The assay dramatically reduces the need for second surgery," he said, and the high negative predictive value should "assure the pathologist, surgeon and patient that occult metastases are unlikely."
Identifying micro-metastases "takes a lot of time and money," said conference co-chair Martine Piccart, M.D., Ph.D., also of Institut Jules Bordet but not part of the study.
"The new technique allows you to make the diagnosis of micro-metastases while the surgery is underway, meaning the patient does not have to suffer the disruption of undergoing another operation," Dr. Piccart said in a statement.
"Remarkably, when the new test gives a negative result -- meaning it finds no spread of cancer to the sentinel node -- it really predicts very well the status of the other lymph nodes," she said.
The researchers did not report study support or potential conflicts.
Primary source: IMPAKT Breast Cancer Conference Source reference: Larsimont D et al. "Prediction of axillary status from sentinel lymph node testing with an intra-operative RT-PCR test - multi-center analysis of 1138 patients." IMPAKT 2009; Abstract 400.
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