Small biopsies work for big tumors

WASHINGTON, Aug 23, 2005 (United Press International via COMTEX) -- For breast-cancer patients, knowing whether the cancer has spread to the lymph nodes under the armpit is crucial to survival. When the breast tumor is larger than about 5 centimeters, doctors usually remove the whole cluster of lymph nodes in their quest to find out.

Now, a new study has found that a less invasive method of testing may be possible for large tumors.

The technique of "sentinel node biopsy" presumes that the spread of cancer proceeds in a logical fashion, from nodes closer to the breast to nodes farther away. Blue dye is injected into the area near the tumor, and the dye follows the path that a spreading cancer would take. The nodes that initially absorb the dye, referred to as sentinel nodes, are removed and analyzed.

"If the sentinel node is clean, then we don't have to do any more armpit surgery," lead author David Ollila, an associate professor of surgery at the University of North Carolina at Chapel Hill School of Medicine, told United Press International. Further surgery is only done if the sentinel node is found to be diseased.

"No patient derives any benefit from taking out normal lymph nodes," Ollila said. When all the lymph nodes are removed, patients risk the condition of lymphedema, or swelling of the arm. Ollila said the risk of lymphedema when only one or two lymph nodes are removed is near zero.

Ollila said sentinel-node biopsies have been used for smaller breast tumors, but the technique has not been used for large tumors due to concerns about a high false-negative rate.

Ollila's study, published in the September issue of The American Journal of Surgery, followed 21 women with breast tumors ranging in size from 3.5 centimeters to 12 centimeters for a median three years after they were treated with sentinel-node biopsies. Fifty-seven percent of the patients had no evidence of tumor in the sentinel node, and thus received no further node-removal surgery. During the follow-up period, none of the patients developed cancer in the lymph nodes.

The challenge now, Ollila said, is to replicate these results on a wider scale, adding that researchers in Michigan and at the University of South Florida's Moffit Cancer Center in Tampa are also working on the issue.

"This is a controversial area for us in breast-cancer management," Ollila said. "We're going to press forward because we think the patient derives a benefit."

All of the patients in Ollila's study had the sentinel-node biopsies done before they received chemotherapy. Ollila said current standard practice administers chemotherapy before doing any sort of surgery to reduce the size of the tumor. This may cause a problem for sentinel-node biopsies, because lymph channels can harden during the course of chemotherapy, making sentinel nodes hard to find.

A recent analysis of multiple studies on sentinel-node biopsies done after chemotherapy, cited in Ollila's study, found an 11-percent false-negative rate.