Endocrine Abstracts

The management of loco-regional metastases in patients with differentiated thyroid carcinoma is still debated. Current American Thyroid Association guidelines state that in this context the main goal is to differentiate between low-volume metastatic disease that will progress and that remaining stable over time.

Aim of our study was to evaluate the behavior of suspicious or cytologically confirmed lymph node metastases, detected after initial treatment (i.e. thyroidectomy with or without cervical lymphadenectomy and radioiodine treatment), in patients with differentiated thyroid carcinoma. Secondary endpoints were the analysis of predictive factors useful to precociously recognize the lesions with a more aggressive behavior. We retrospectively evaluated 95 patients, who were followed-up with serum tumor biomarker evaluation and neck ultrasound every 6-12 months, who had a persistent finding of suspicious neck lymph nodes and a minimum follow-up of 12 months. The lymph-nodal disease was considered aggressive when (a) there was a growth of at least 5 mm in the longest diameter at ultrasound, (b) appearance of at least one new suspicious lymph node, (c) at least one lymph-node was PET-FDG avid. After a mean follow-up of 9 years, 75/95 (79%) patients had a stable disease, while 20/95 (21%) had progressive loco-regional disease. Patients with a more aggressive disease were more frequently male (50% vs 25.3%, P=0.03), older (mean age was 54.3 vs 38 years old, P=0.0003), and with a larger primary tumor (31.8 vs 20 mm, P=0.005). We did not find significant differences regarding TNM, histology, papillary thyroid cancer variant, extrathyroidal extension, ablative radioiodine dose, stimulated thyroglobulin at first radioactive iodine, positive thyroglobulin antibodies after initial treatment, finding of distant metastases at the end of follow-up. At the end of follow-up, 16/20 patients with progressive loco-regional disease had a structural disease despite further treatments (i.e. lymphadenectomy, external beam radiotherapy, radioiodine treatment, tyrosine kinase inhibitors). Our study reports that a high majority of patients with cervical lymph node metastases can be safely followed-up with serial neck ultrasound and serum tumor biomarker evaluation. In case of suspicion, a PET-FDG scan may be necessary. The remaining 20% of patients, in particular male, older patients, and with a larger tumor size at surgery, may have lymph node metastases with an aggressive behavior requiring additional treatments.