WEDNESDAY, Jan. 19 (HealthDay News) -- For decades, doctors have debated about how to best determine whether a patient's breast cancer has spread, especially in the earliest cases of metastases.
Now, researchers have compared two approaches -- a sentinel lymph node biopsy alone, or the sentinel biopsy combined with axillary dissection, which is a more invasive procedure that can spot hidden, smaller metastases. The finding: As long as the larger metastases (2 millimeters in diameter and up) are found, the outcomes of the two procedures are similar.
"What we showed was the significance of these small micrometastases is very small," explained study author Dr. Donald L. Weaver, a professor of pathology at the University of Vermont College of Medicine and Vermont Cancer Center. The report is published in the Jan. 19 online edition of the New England Journal of Medicine.
Weaver and his team randomly assigned 5,611 women with breast cancer but clinically negative axillary nodes to one of two groups -- about half underwent the sentinel node biopsy alone and the other half underwent the biopsy plus axillary dissection.
A sentinel lymph node is the first lymph node to which cancer is likely to spread. The biopsy is based on the idea that cancer cells metastasize in an orderly fashion.
At the centers participating in the study, the sentinel node exam was designed to find all metastases more than 2 millimeters in dimension, known as macrometastases.
Follow-up data was available for 1,924 in the combination group and 1,960 in the biopsy-only group. In the biopsy-only group, 300 were positive for metastases, while 316 were positive in the combination group.
Of those who had metastases, 172 were micrometastases, 14 had macrometastases and 430 had even tinier spreads, known as isolated tumor-cell clusters, the study authors found.
The researchers look
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