BETHESDA, MdBoth patients and surgeons are being sought for two
complementary phase III randomized studies to determine the efficacy
of sentinel lymph node (SLN) biopsy in breast cancer patients.
Although sentinel node biopsy has attracted widespread
attention by surgeons and patients alike, the procedure has not been
compared to the time-tested standard of complete axillary dissection
in a clinical trial designed to assess cancer recurrences and overall
survival, said Jeffrey Abrams, MD, of the National Cancer
Institutes Division of Cancer Treatment and Diagnosis.
The SLN studies are being conducted by two NCI-sponsored clinical
trial cooperative groups: the National Surgical Adjuvant Breast and
Bowel Project (NSABP) and the newly formed American College of
SurgeonsOncology Group (ACOS-OG).
Sentinel nodes are the nodes to which breast cancer is most likely to
spread first. In a sentinel node biopsy, surgeons remove only one or
a few of these nodes at lumpectomy or mastectomy for analysis.
Research suggests that the sentinel node can be used to
determine whether cancer has spread to other lymph nodes, but we
still dont know what impact removing only the sentinel node
will have on cancer control and survival, said David Krag, MD,
of the University of Vermont, a surgical leader in the NSABP trial.
He added: If we really want to know whether sentinel node
biopsy can safely replace more invasive surgery, participation by
surgeons across the country is essential.
To participate in either study, a surgeon must provide documentation
of his or her experience or undergo additional training. Currently,
142 surgeons in 35 states, Washington, DC, and three Canadian
provinces have been approved.
The two studies address two different types of breast cancer
patients. The NSABP trial seeks to determine whether the sentinel
node procedure can replace complete axillary lymph node dissection in
patients with negative sentinel nodes. The ACOSOG study is
examining the question in women with positive sentinel nodes.
Both studies hope to learn whether the survival of sentinel node
biopsy patients is any different from that of patients receiving a
complete axillary node dissection. They will also compare the rate of
complications between sentinel node biopsy and full dissection.
Until this type of comparison occurs, surgeons are well advised
to consider participation in a clinical trial if they and their
patients are interested in this procedure, Dr. Abrams said.
The NSABP Study
For its study, the NSABP plans to accrue 4,000 patients over 4 years;
500 have already been enrolled at 40 US sites and 6 in Canada.
The protocol calls for randomizing the women to two groups. One group
will undergo a lumpectomy or mastectomy and a sentinel node biopsy
followed by axillary dissection. The second group will undergo
surgery and sentinel node removal. If the sentinel node biopsy is
positive, surgeons will remove the remaining axillary nodes.
Patients will be followed at 1 and 3 weeks, then every 6 months for 3
years, and annually after that.
The ACOS-OG Trial
The ACOSOG trial is currently enrolling patients at 41 US sites
and expects to accrue 1,900 patients over 3.8 years. In this study,
early breast cancer patients will have a lumpectomy and a sentinel
node biopsy. The women with positive biopsies will be randomized to
two groups. One arm will undergo the standard treatment of full
axillary dissection; the second group will have no other lymph nodes
removed at the time.
Conventional full axillary node removal can result in several
complications and, thus, the appeal of the sentinel node biopsy among
breast cancer patients.
Some reports indicate that more than 80% of women who undergo a
complete axillary dissection have at least one complication after
surgery, the NCI reports. These complications are of
varying severity, but can include lymphedema, numbness, a persistent
burning sensation, infection, and limited movement of the