Aim: We applied the Sentinel Lymph Node (SLN) technique using the lymphoscintigraphy (LS)
preoperatively and the gamma-probe (GP) intraoperatively to evaluate the feasibility, safety and
accuracy of the SLN in Papillary Thyroid Cancer (PTC).Materials and Methods: Of 84 patients
with PTC, we enrolled 40 with at least one year follow-up from thyroidectomy. The day before
surgery, they were submitted to US guided peri-tumoral injection of about 120 MBq of 99mTc-
Nanocoll®. The LS was performed 30-180 min after the injection. Then, a thyroidectomy was
done. In 25 patients, after removal of any SLN, an average of 6 lymph nodes were excised in the
SLN compartment. The SLN was sent separately with other lymph nodes to the pathologist for
histopathological analysis.Results: The SLN was identified in all patients. The SLN localization
side by the GP was: central compartment in 25 patients (64%), laterocervical compartment on the
same side of the tumor in 12 patients (31%), laterocervical compartment on the opposite side of
the tumor in 2 patients (5%). In 1 cases the metastatic lymph nodes were peri-thyroid, so we
removed them with thyroidectomy. Of the 39 patients in whom the SLN was detected
intraoperatively, 30 patients (75%) had no SLN metastases, 8 patients (20%) had SLN
metastases, and one patient (2.5%) had SLN micrometastases on final pathology. In 4 patients
(10%), no SLN metastases were detected, but other lymph nodes belonging to the SLN
compartment were positive for cancer. One year follow-up was negative for disease in all
cases.Conclusions: The SLN technique identifies the lymphatic drainage in PTC; thus, by
removing both the SLN and all other lymph nodes belonging to the same compartment, all
possible metastatic lymph node should have been resected. Our study shows that the SLN
technique is accurate because positive localization of SLN in 97.5% of cases and feasible
because it is repeatable. Moreover, the SLN technique allows to guide a target lymph node
biopsy, to identify lymph nodes metastases not evaluable on preoperative imaging studies and to
identify micrometastases. Locoregional lymphoadenectomy on the same side of the SLN
represent a rationale treatment for lymph nodes in PTC. This attitude may represent a “golden
mean” between central and laterocervical lymphoadenectomy and postoperative radioiodine
therapy alone, allowing better prognostic definition, with no increase in morbidity
