UF Surgeons Study Refinement Of Sentinel Node Biopsy For Breast Cancer Patients

September 24, 2002

GAINESVILLE, Fla. — University of Florida surgeons have simplified the way they identify which lymph node is reached first by breast cancer cells that escape from a tumor. The refined approach improves the accuracy of sentinel node biopsy, an increasingly popular method of gauging whether the disease has spread.

Physicians using the technique, which involves injecting a radioactive tracer into sites above and adjacent to breast tumors, also could better tailor the way they deliver radiation because the approach identifies the small percentage of patientswhose sentinel node is actually located in the chest, not the armpit. UF surgeons reported findings from a retrospective study of the dual-injection method in the August issue of the journal American Surgeon.

In the past few years, many surgeons seeking to determine how advanced a patient’s cancer is have switched from removing 10 to 15 lymph nodes from under the arm-the traditional procedure known as axillary node dissection-to sentinel node biopsy because the method is associated with less pain and fewer complications, and has proved just as accurate, said cancer surgeon Dr. D. Scott Lind, who is affiliated with the UF Shands Cancer Center.

If the sentinel node is free of cancer, patients often can avoid having additional nodes surgically removed, a practice that can lead to nerve damage, chronic swelling, restricted shoulder movement and pain.

Yet the optimal way of performing sentinel node biopsy remains controversial, Lind said, and techniques vary widely from institution to institution and among individual surgeons.

“With respect to treating breast cancer, we have become much, much less invasive and less radical,” said Lind, a professor of surgery at UF’s College of Medicine. “In the last century we went from radical mastectomy to learning that you can do breast-conserving therapy and can spare the patient the morbidity of taking the whole breast off, with equivalent outcomes. In the last 10 years, nearly every patient who previously would have undergone axillary dissection undergoes sentinel node biopsy. The problem is that’s rapidly becoming the standard of care without a standard technique. A lot of people are doing it in different ways.”

Typically, a surgeon injects a small amount of a radioactive tracer around the patient’s tumor, then locates the sentinel node with a hand-held device used to detect the tracer’s path. A blue dye also is injected into the breast tissue to help visually confirm the node’s location.

But surgeons continue to debate the ideal site for injecting the tracer and whether using the blue dye is even needed, Lind said. The dilemma has centered on whether it is necessary to inject the marker drug directly into the area where the original tumor was located, technically very difficult.

One in every eight American women will develop breast cancer at some point in their lifetime, the National Cancer Institute estimates.

UF surgeons retrospectively studied 118 patients who were grouped into three categories. Sixty-five had the radioactive tracer injected into the skin over the tumor, six had the injection into the breast tissue around the tumor and 47 had both. Overall, at least one sentinel node was identified in 98.3 percent of the patients. A sentinel node was identified in 98.5 percent of patients receiving an injection in the skin above the tumor, 83.3 percent of those receiving an injection around the tumor and 100 percent of those receiving both.

Although the results showed that injection into the skin overlying the area of the tumor is an accurate localizing technique, using both injection sites helped increase the accuracy of identifying the sentinel node by detecting abnormal patterns of lymph fluid drainage, which are noted in up to 20 percent of breast cancer patients, Lind said. Practitioners then could target radiation treatments accordingly, he said, and spare other women radiation to areas where they don’t really need it.

The study’s authors also questioned the need for using blue dye, which is associated with rare but serious allergic reactions. UF surgeons have abandoned its use, though it continues to be popular among practitioners nationwide.

“We found that using the two injection sites allows us to reliably identify the sentinel node in the most effective fashion,” he said. “And it probably has some advantages because we won’t have to worry about patients having reactions to blue dye, and we can identify nonaxillary sites of disease that may affect treatment planning. This is particularly important with the new breast cancer staging system coming out in January, which will incorporate sentinel node results.”

The UF findings provide unique insight into the care of women with breast cancer, said Dr. Michael Edwards, a professor and chairman of the department of surgery at the University of Arkansas.

“While most of the experts have been narrowly focused on which single site of injection is superior, Dr. Lind and his group have split the dose and shown that injecting at two sites is superior to the ‘one-site injection’ approach,” Edwards said. “It sounds simple, but so much of the highest quality care is just that-simple, and better. They are to be complimented for thinking clearly and considering techniques that other experts and leading centers have overlooked.”