ORLANDOA study 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(Drug information on sulfur) colloid and isosulfan blue dye. A small group also were injected with periareolar fluorescein(Drug information on 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 neoadjuvant chemotherapy.