Applicability of sentinel lymph node biopsy in papillary thyroid cancer

BACKGROUND: The optimal surgical management of papillary thyroid cancer (PTC) for T1-T2 tumors without pre or intmsurgical evidence of lymph node metastasis (cNO) remains controversial, since approximately 40% of patients have lymph node involvement (pN1) which becomes evident when a prophylactic lymphadenectonty (PL) is performed. The aim of this study was to investigate the feasibility of sentinel lymph node (SLN) identification with SPECT/CT lymphoscintigraphy imaging along with intmoperatory image techniques in early stages of PTC undergoing PL of central neck compartment (CNC). METHODS: A single-center, prospective consecutive study was designed for SLN mapping in patients with high suspicion of PTC (Bethesda V or VI) in early stage (eT1-2, eN0). Twenty-four patients underwent SLN identification with preoperative SPECT/CT and planar images (Tc-99m-nanocolloid albumin intratumoral injection). During surgery, SLN located in CNC was found by means of a gamma probe and portable gamma camera, and excised. Afterwards, CNC lymphadenectomy was performed in all cases without modifying the established protocol. RESULTS: SLNs were identified and accurately located in 23 (95.8%) patients. Nodal metastases (pN1) were confirmed in 9 (37.5%) patients, with one false negative case. The sensitivity was 88.9% and negative predictive value (NPV) was 93.3%, would have allowed to avoid PL in more than half of cases, a higher proportion than those found in other similar studies. No complications associated with the procedure were observed. CONCLUSIONS: Our results support that SLN biopsy by SPECT/CT along with intraoperatory image techniques is applicable in early stages of PTC (eT1-2, eN0), allowing to avoid unnecessary PL.