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.