[Lymphatic mapping and biopsy of sentinel lymph node in patients with breast cancer. Results of the first phase of a study].

BACKGROUND: The standard surgical treatment in breast cancer patient is resection of the primary tumor and axillary lymphadenectomy; nevertheless almost 50% of patients without axillary palpable nodes do not have axillary metastasis in the axillary dissection specimen. In theory the sentinel node identification (lymphatic mapping) selects patients with high risk of hidden metastasis and avoids unnecessary axillary dissections, the technique is performed with blue dye, radio colloid or both. OBJECTIVE: To know the sentinel node value in axillary staging in patients with invasive breast cancer without palpable nodes. MATERIAL AND METHODS: Prospective study including 87 breast cancer patients stage I-II without palpable nodes. In 65 we use blue dye only and in 22 blue dye and Tc99 nanocoloid, all patients were submitted to axillary dissection; the sentinel node was study by imprint cytology, frozen sections and H/E stains. Sensibility, success index, negative predictive value, positive predictive value and false negative rate were calculated. RESULTS: Sentinel node was identified in 57/65 patients (87%) in blue dye group and in all the patients in combined technique group. There were sentinel node metastasis in 19/79 (24%), 4/19 patients had metastatic non-sentinel nodes without sentinel node metastasis (false negative rate = 17%), all the false negative sentinel nodes in the blue dye only group. CONCLUSIONS: Lymphatic mapping and sentinel node biopsy could avoid unnecessary axillary dissections in early stages of breast cancer; the combined technique reduces the false negative rate and increases the index of success.