(RxWiki News) Women whose breast cancer has spread to the lymph nodes often have chemotherapy. This can be done before surgery to give her the possibility of having breast-conserving therapy. But how do physicians know if there’s still cancer in the lymph nodes after the chemotherapy?
Researchers conducted a study to see if removing only a few lymph nodes closest to the breast tumor — called sentinel lymph node (SLN) surgery — is an accurate method of detecting any remaining cancer in the lymph nodes following chemotherapy.
The study found that SLN biopsy was not as reliable in detecting remaining cancer in the lymph nodes as surgery that removes all the lymph nodes in the armpit (axillary).
Careful patient selection may result in increasing the accuracy of the SLN procedure.
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The American College of Surgeons Oncology Group, led by Judy Boughey, MD, a breast surgeon at Mayo Clinic, conducted this study to determine the false-negative rate of SLN surgery in patients with node-positive (has spread to the lymph nodes) breast cancer and who were receiving chemotherapy before surgery.
A false negative means that a test finds no cancer when in fact disease exists.
"Since treatment with chemotherapy before surgery can eliminate cancer in the lymph nodes in some patients, we were interested in evaluating whether sentinel lymph node surgery could successfully identify whether cancer remained in the lymph nodes after chemotherapy," Dr. Boughey said in a prepared statement.
“Accurate determination of axillary involvement after chemotherapy is important; however, removing all axillary nodes to assess for residual nodal disease exposes many patients to the potential side effects of surgery and, potentially, only a subset will benefit,” the authors wrote.
Patrick D. Maguire, MD, a radiation oncologist with Coastal Carolina Radiation and Oncology in Wilmington, NC, told dailyRx News, “SLN biopsy has become the surgical standard of care for evaluating axillary lymph nodes in most patients diagnosed with breast cancer. The procedure has decreased the potential for side effects for patients relative to axillary lymph node dissection (ALND) including pain, numbness, and/or permanent lymphedema (swelling) of the arm, “ Dr. Maguire explained.
“However, the role of SLN after patients have received neoadjuvant (before surgery) chemotherapy is uncertain,” said Dr. Maguire, who was not involved in the study.
Most (74.6 percent) of the chemotherapy given was anthracycline- and taxane-based, which has been shown to eradicate nodal disease in approximately 30 to 40 percent of patients, the authors reported.
The researchers recruited 756 women from 136 institutions from July 2009 to June 2011 who had various stages of breast cancer and received chemotherapy before surgery.
Of this group, 649 had both SLN biopsy and ALND.
In 39 patients, cancer was not identified in the SLNs but was found in lymph nodes obtained with ALND, resulting in a false negative rate of 12.6 percent.
“I agree that most oncologists would consider this rate (greater than 10 percent) too high for routine use of SLN without ALND,” said Dr. Maguire, the author of When Cancer Hits Home: An Empowered Patient is the Best Weapon Against Cancer.
“However, if breast surgeons are able to narrow the selection of patients for SLN after neoadjuvant chemotherapy to a subgroup, perhaps the false negative rate could be improved,” Dr. Maguire said.
He concluded, “In the meantime, patients should be informed of this important study so they can make truly informed decisions with their treating physicians about SLN and/or ALND in these challenging situations.”
This study was published online October 7 in The Journal of the American Medical Association (JAMA).
The research was supported by a National Cancer Institute award to the American College of Surgeons Oncology Group.
Several of the authors reported financial relationship with various commercial and governmental organizations.