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 shoulders.