reported at the Era of Hope Department of Defense Breast Cancer Program meeting
adds more evidence supporting wider use of sentinel lymph node (SLN) biopsy by
surgeons skilled in the technique.
"We wanted to see if we could use sentinel node biopsy for a
diverse group of patients," said Lorraine Tafra, MD, director of The Breast
Center at the Anne Arundel Medical Center, Annapolis, Maryland. "And as it
turns out, the vast majority of breast cancer patients can benefit from
sentinel node biopsy."
The ongoing multicenter trial began in 1997 to determine
which factors may increase the chance of false-negative results from sentinel
node biopsy. The study has enrolled 1,236 patients. Results of sentinel node
biopsy have been compared with axillary node dissection in a group of 780
patients who underwent both procedures.
On most patients, surgeons used a peritumoral and/or
intradermal injection technique, with both technetium sulfur colloid and
isosulfan blue dye. A small group also were injected with periareolar
fluorescein. Intraoperatively, a variety of all commercially available gamma
probes were used to detect the sentinel nodes.
The study found three factors that significantly increased
the risk of a false-negative result: Prior extensive surgery in the breast,
significant disease in the lymph nodes, and the number of sentinel nodes found
by the surgeon. Dr. Tafra surmised that prior surgery interrupted the normal
lymph flow, extensive disease in the lymph nodes blocked the dye from arriving,
and inexperienced surgeons often missed additional sentinel nodes.
"You’ve got to find the sentinel nodes," she explained. "If
you find one, look around for more. Most patients have two. If you miss the
second node, you may miss the node that contains metastatic disease. The
metastatic disease is not always in the first sentinel node that is removed."
The data showed no association between false negatives and
patient age, tumor type, tumor location, multiple vs single site disease, or