HAMBURGIn women with operable breast cancer of small size, sentinel node biopsy can be used to predict the status of the axillary lymph nodes and thereby avoid unnecessary axillary dissection, according to a report from the European Institute of Oncology in Milan presented at the Ninth European Cancer Conference (ECCO 9).
This method is an important step forward in the search for less aggressive treatments for breast cancer, without loss of information necessary for accurate therapy, Dr. Viviana Galimberti said at the meeting. This is especially relevant in an era when mammographic screening is detecting much smaller breast tumors that prove to be node negative on histologic examination, she noted.
In their study, the Milan researchers applied lymphoscintigraphy to identify the first node to receive lymph from the tumor area. They marked the skin projection of this sentinel node, and used a handheld, radioguided gamma ray probe to guide them in making a small cutaneous axillary incision through which the sentinel node could be surgically removed. Complete axillary node dissection was then performed through a standard incision.
Sentinel nodes were readily identified and analyzed in 238 of 241 consecutive women with operable breast cancer treated at the European Institute of Oncology. In 109 cases, the sentinel node was positive as were some other nodes, Dr. Galimberti said. In 123 cases, the sentinel node was negative and all other nodes were negative.
In only six cases was the sentinel node free of disease while other nodes were positive for micrometastases. In two of these six cases, the tumor was multifocal, and in the other four cases, the tumor was monofocal but greater than 1.2 cm in size, she said. For tumors less than 1.2 cm, the predictive value of sentinel node biopsy was 100%.
In 23 cases, the sentinel node was judged to be negative at the frozen section but later found to be positive for micrometastases on definitive examination. It is most important that future research should seek more reliable ways of finding microfoci of metastatic cells, Dr. Galimberti urged.
She cautioned that a randomized controlled trial will be necessary to confirm the safety of routinely abandoning complete axillary dissection in all women with a negative sentinel node.