A modified sentinel node and occult lesion localization (SNOLL) technique in non-palpable breast cancer: a pilot study

Background: The spread of mammographic screening programs has allowed an increasing amount of early breast cancer diagnosis. A modern approach to non-palpable breast lesions requires an accurate intraoperative localization, in order to achieve a complete surgical resection. In addiction, the assessment of lymph node status is mandatory as it represents a major prognostic factor in these patients. The aim of this study is to evaluate the reliability of a modified technical approach using a single nanocolloidal radiotracer to localize both sentinel node and breast occult lesion. Methods: Twenty-five patients with a single non-palpable breast lesions and clinically negative axilla were enrolled. In the same day of surgery, patients underwent intratumoral and peritumoral administration of Tc-99m-labeled nanocolloid tracer under sonographic guidance. A lymphoscintigraphy was performed to localize the sentinel lymph node and its cutaneous projection was marked on the skin in order to guide the surgeon to an optimal incision. During surgery an hand-held gamma-detection probe was used to select the best surgical access route and to guide localization of both occult breast lesion and sentinel lymph node. After specimen excision, the surgical field was checked with the gamma-probe to verify the absence of residual sources of significant radioactivity, thereby ensuring a radical treatment in a single surgical session and minimizing normal tissue excision. Results: Both targeted breast lesion and sentinel lymph node were localized and removed at the first attempt in every patients and histopathological diagnosis of malignancy was confirmed in 25/26 samples. Non-palpable lesions were included within the surgical margins in all patients and in all samples surgical margins were free from neoplastic infiltration thus avoiding any further reintervention. Only two patients showed metastatic involvement of sentinel lymph node. Conclusions: The modified sentinel node and occult lesion localization (SNOLL) technique performed with a single injection of nanocolloidal radiotracer has shown an excellent intraoperative identification rate of both non-palpable lesion and sentinel lymph node. This procedure offers, as opposed to standard techniques, an accurate, simple and reliable approach to the management of non-palpable breast cancer.