Intraoperative examination of the sentinel lymph node, which is the axillary lymph node first reached by drainage from the tumor, has attracted interest for use in breast cancer management. This diagnostic approach may be useful in avoiding complete axillary lymph node resection for staging purposes and in staging breast cancer patients who are candidates for chemotherapy or radiation treatment. Viale and associates assessed the feasibility and accuracy of intraoperative sentinel lymph node examination in patients with breast cancer.
Women with operable breast cancer (stages 1 or 2) with no clinical evidence of lymph node involvement before surgery were eligible for the study. The day before surgery, a small quantity of technetium-labeled colloid was injected into each patient to identify the axillary sentinel lymph node. At the beginning of the surgery, the lymph node was removed, followed by immediate frozen-section examination. Breast surgery then continued as planned, including complete lymph node dissection. Standard pathologic evaluation was performed on all remaining tissue submitted.
A total of 155 patients enrolled in the study, and of these, 117 had a single sentinel lymph node identified. The mean number of sentinel lymph nodes examined was 1.3, and all frozen-section examinations were completed within 65 minutes. Axillary lymph node dissection yielded a mean of more than 26 lymph nodes on pathologic specimen. Sentinel lymph node metastases were found in 70 patients (45 percent), and of these, 37 (52.8 percent) had metastasis in only that lymph node. Sentinel lymph nodes were negative for metastatic disease in 85 patients, and of these, only five had a single metastatic lymph node in the first axillary level. The general concordance between sentinel and axillary lymph node status was more than 96 percent, sensitivity was more than 93 percent, and the negative predictive value was 94 percent.
The authors conclude that the intraoperative examination of the sentinel lymph node is a feasible, effective approach in predicting lymph node status in breast cancer. The principal advantage to intraoperative examination is that it limits surgical treatment to a single session. The decision to proceed with complete dissection can rest entirely on the presence or absence of metastatic disease in the sentinel lymph node. If there is no metastases, lymph node dissection may not be necessary. Use of this diagnostic approach can reduce the number of lymph node dissections, thereby decreasing the morbidity associated with this procedure.