A national study underway at Virginia Commonwealth University (VCU) will determine whether breast cancer patients can benefit from a biopsy procedure that has been successfully used for skin cancer patients. Patients with melanoma, the most serious kind of skin cancer, have benefited from an advance that has reduced the pain and complications of surgery performed to ascertain whether their cancer has spread.
For patients with cancer, the choice of follow-up treatment depends largely on a surgical biopsy that reveals whether the cancer has spread beyond its initial site. First signs of spreading appear in the lymph nodes. If the nodes show no trace of cancer, additional therapy 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 the 40% to 50% of patients with intermediate-thickness lesions whose melanoma may have spread to the lymph nodes," said John C. D'Emilia, md, an assistant professor in the Division of Surgical Oncology at VCU's Medical College of Virginia. "The traditional biopsy's pain and complications--such as nerve damage and swelling--were often worse than the surgery to remove the melanoma. By removing only the sentinel node, which is the gatekeeper of the lymph-node colony, we give patients a simpler, equally accurate answer as to whether their cancer has spread and whether further surgery and other therapies are necessary."
The gatekeeper sentinel node is the first in the colony to show signs of invasion. Recent studies show that in 99% of cases, a biopsy of the sentinel node will provide surgeons with the same information they would get from removing the entire colony. D'Emilia has performed sentinel node biopsies for 2 years on patients whose melanoma was likely to have spread, and believes the procedure will become standard treatment.
Sentinel node biopsy is performed as an outpatient procedure with minimal discomfort to the patient. The patient needs only local anesthesia while the surgeon removes the single node, located about 1/2 to 1 inch under the skin's surface. To find the sentinel node, the surgeon injects the cancer site with a small amount of radioactive tracer, which is flushed through the lymphatic system to the node colony. The tracer is absorbed exclusively by the sentinel node, which is then relatively easy to locate with a Geiger counter-like gamma probe.
In the past, few treatment options were available for patients with a melanoma that had spread; often they could only watch for the development of a new cancer. As a result, surgeons debated whether the benefits of removing the entire lymph-node colony outweighed the surgery's complications. However, recent clinical advances have resulted in treatments that may prevent a new cancer from developing. With the availability of these therapies, many physicians and patients use the sentinel node biopsy to decide whether follow-up treatment is necessary.
Usefulness in Breast Cancer Under Study
The successful use of sentinel node biopsy for patients with melanoma has led physicians to investigate its usefulness for patients with breast cancer. As with melanoma, treatment options are largely tied to whether the cancer has spread to the nodes. Surgical treatment for breast cancer currently includes removal of both the malignant breast tumor and the lymph node colony located under the nearest armpit, which can result in additional pain and complications.
VCU is one of 12 sites around the country that, together, expect to enroll 1,000 patients in a National Cancer Institute-funded trial. D'Emilia believes that this trial, like the earlier melanoma studies, may reveal that the removal of the sentinel node can accurately show whether the breast cancer has spread. To determine whether the sentinel node provides the same information as the entire colony, the study's investigators will look for traces of cancer in both the sentinel node and the remainder of the colony.
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