[Sentinel node localization in breast cancer. Periareolar injection of radiocolloid]

Traditional lymphadenectomy is being replaced by sentinel node biopsy in initial management of early stage breast cancer. The aim of this study was to validate the technique in our center, where we perform preoperative lymphoscintigraphy and intraoperative detection of sentinel node, after periareolar radiotracer and peritumoral blue dye injection. Sixty patients, breast cancer stages I and II, were included. Lymphatic mapping was performed the day before surgery, after the administration of 74 MBq 99mTc sulfur colloid in periareolar subdermal tissue. Surgical detection of sentinel node through gamma probe was followed by intraoperative and occasionally delayed biopsies. Finally, full axillary node dissection was completed. Lymphoscintigraphy identified sentinel node in 78% of the patients (47/60): 43 in axilla, 4 in internal mammary chain. Probe guided axillary detection was achieved in 88% (53/60): in every patient with axillar migration in scan, in 9/13 without imaged drainage and in 1/4 with internal mammary chain migration. Sensitivity of blue dye technique was 75% (45/60), the concordance between both procedures being high. Considering both, the overall success rate of surgical detection was 90% (54/60); if we exclude those patients who showed exclusive extraaxillar drainage, the success rate reaches 95%. Malignancy was found in 24% of sentinel nodes removed (13/54); it being the only metastatic axillary node in 4/13. No false negative sentinel nodes were found. Therefore, negative predictive value and accuracy were 100%. These results allow us to validate the technique in our center.