Success of Sentinel Lymph Node Biopsy in Melanoma Leads to Test in Breast Cancer

A national study underway at Virginia Commonwealth University(VCU) will determine whether breast cancer patients can benefitfrom a biopsy procedure that has been successfully used for skincancer patients. Patients with melanoma, the most serious kindof skin cancer, have benefited from an advance that has reducedthe pain and complications of surgery performed to ascertain whethertheir cancer has spread.

For patients with cancer, the choice of follow-up treatment dependslargely on a surgical biopsy that reveals whether the cancer hasspread beyond its initial site. First signs of spreading appearin the lymph nodes. If the nodes show no trace of cancer, additionaltherapy may not be necessary. However, if the cancer has spread,follow-up treatments could prevent a recurrence.

"The sentinel node biopsy is a tremendous advantage for the40% to 50% of patients with intermediate-thickness lesions whosemelanoma may have spread to the lymph nodes," said John C.D'Emilia, md, an assistant professor in the Division of SurgicalOncology at VCU's Medical College of Virginia. "The traditionalbiopsy's pain and complications--such as nerve damage and swelling--wereoften worse than the surgery to remove the melanoma. By removingonly the sentinel node, which is the gatekeeper of the lymph-nodecolony, we give patients a simpler, equally accurate answer asto whether their cancer has spread and whether further surgeryand other therapies are necessary."

The gatekeeper sentinel node is the first in the colony to showsigns of invasion. Recent studies show that in 99% of cases, abiopsy of the sentinel node will provide surgeons with the sameinformation they would get from removing the entire colony. D'Emiliahas performed sentinel node biopsies for 2 years on patients whosemelanoma was likely to have spread, and believes the procedurewill become standard treatment.

Sentinel node biopsy is performed as an outpatient procedure withminimal discomfort to the patient. The patient needs only localanesthesia while the surgeon removes the single node, locatedabout 1/2 to 1 inch under the skin's surface. To find the sentinelnode, the surgeon injects the cancer site with a small amountof radioactive tracer, which is flushed through the lymphaticsystem to the node colony. The tracer is absorbed exclusivelyby the sentinel node, which is then relatively easy to locatewith a Geiger counter-like gamma probe.

In the past, few treatment options were available for patientswith a melanoma that had spread; often they could only watch forthe development of a new cancer. As a result, surgeons debatedwhether the benefits of removing the entire lymph-node colonyoutweighed the surgery's complications. However, recent clinicaladvances have resulted in treatments that may prevent a new cancerfrom developing. With the availability of these therapies, manyphysicians and patients use the sentinel node biopsy to decidewhether follow-up treatment is necessary.

Usefulness in Breast Cancer Under Study

The successful use of sentinel node biopsy for patients with melanomahas led physicians to investigate its usefulness for patientswith breast cancer. As with melanoma, treatment options are largelytied to whether the cancer has spread to the nodes. Surgical treatmentfor breast cancer currently includes removal of both the malignantbreast tumor and the lymph node colony located under the nearestarmpit, which can result in additional pain and complications.

VCU is one of 12 sites around the country that, together, expectto enroll 1,000 patients in a National Cancer Institute-fundedtrial. D'Emilia believes that this trial, like the earlier melanomastudies, may reveal that the removal of the sentinel node canaccurately show whether the breast cancer has spread. To determinewhether the sentinel node provides the same information as theentire colony, the study's investigators will look for tracesof cancer in both the sentinel node and the remainder of the colony.