Thyroglobulin Measurement in Fine-Needle Aspiration Improves the Diagnosis of Cervical Lymph Node Metastases in Papillary Thyroid Carcinoma.

BACKGROUND: Papillary thyroid carcinoma (PTC) is frequently associated with cervical lymph node metastases. Guidelines recommend performing ultrasound-guided fine-needle aspiration cytology (FNAC) for suspicious nodes to guide management. No specific recommendations are available for the use of FNA thyroglobulin assay (FNA-Tg). This study investigated the diagnostic value of performing FNAC and FNA-Tg. METHODS: Patient demographics, preoperative investigations, surgery, and lymph node pathology were collected for patients with PTC who underwent lateral neck lymphadenectomy and central compartment reexploration from January 2000 to July 2015. Sensitivities and accuracies were obtained. Patients with both diagnostic studies performed were compared using McNemar's test of paired proportion. Patient, imaging, and lymph node characteristics were correlated with test accuracy. RESULTS: The 480 patients in this study underwent 706 lateral neck dissections or central compartment reexploration. All the patients underwent preoperative neck ultrasound. Among these patients, FNAC alone was performed before 426 operations (60 %), FNAC with FNA-Tg before 105 operations (15 %), and surgery without biopsy for 175 patients (25 %). The sensitivity, positive predictive value, and accuracy were respectively 96, 95, 100 % for FNAC, 99, 97, and 97 % for FNA-Tg, and 95, 92, and 97 % for FNAC in combination with FNA-Tg. In the subgroup of patients who had both tests performed, the sensitivity of FNA-Tg was superior to that of FNAC (95 vs 87 %; p = 0.04). The addition of FNA-Tg to FNAC increased the detection of metastatic PTC by 13 %. CONCLUSIONS: For diagnosing cervical lymph node metastases in PTC, FNA-Tg is a valuable adjunct to FNAC. Its use should be considered to avoid missing metastatic disease in patients who may benefit from lymphadenectomy.

Favorable Early Outcomes With Thyroid Lobectomy for Low-Risk Papillary Thyroid Cancer: The Mayo Clinic Experience.

BACKGROUND: Until 2015, standard of care for low-risk papillary thyroid cancer (PTC) >1 cm was a total or near-total thyroidectomy. Despite changes in guidelines and surgical management of low-risk PTC since 2015, little data are available regarding the effect on the need for additional surgery or risk for development of lymph node metastases. Our aim was to determine outcomes in patients who underwent initial thyroid lobectomy for low-risk PTC at a high-volume tertiary care institution. METHODS: Retrospective review of patients ≥18 years old with biopsy proven low-risk PTC 1-4 cm who underwent partial thyroidectomy (eg, lobectomy/isthmusectomy) at Mayo Clinic, Rochester, MN, between March 2016 and June 30, 2019. RESULTS: From 1481 thyroidectomies performed during study period, 940 contained PTC on final pathology. Of these, 87 (of 123) patients who had an initial thyroid lobectomy met inclusion criteria. Five (6%) of these patients proceeded to completion thyroidectomy (CT), with 3 requiring CT and radioactive iodine in the first postoperative year and 2 undergoing only CT in the second postoperative year. No postoperative complications were reported. No patient in this cohort required additional surgery or treatment for newly discovered lymph node metastases during the follow-up period. 43 (of 72, 60%) patients not on thyroxine therapy preoperatively were started on thyroxine therapy postoperatively. CONCLUSIONS: Early outcomes for those undergoing thyroid lobectomy for low-risk PTC at our institution have been favorable. These results support the 2015 American Thyroid Association guidelines to offer lobectomy for those with low-risk PTC 1-4 cm.