Long-term outcome of 495 TNM stage I or II patients with differentiated thyroid carcinoma followed up with neck ultrasonography and thyroglobulin measurements on T4 treatment.

OBJECTIVE: Recent guidelines for surveillance of patients with differentiated thyroid carcinoma emphasize TSH-stimulated serum thyroglobulin (Tg) measurements and neck ultrasonographies (US) over Tg measurements on T(4) and diagnostic whole body scans (DxWBS). We evaluated the safety and efficacy of a surveillance paradigm comprising yearly T(4)-suppressed Tg measurements and neck US every second year, with an increase in Tg to a detectable level being a prompt indication for DxWBS.
DESIGN: A retrospective study with a median follow-up of 11.6 years. PATIENTS AND MEASUREMENTS: Recurrences, cancer-specific deaths and number of neck US, fine needle aspiration biopsies (FNABs) and operations performed were evaluated in 495 low-risk (TNM stage I and II) patients, the majority of whom had total thyroidectomy and radioactive iodine remnant ablation as initial treatment.
RESULTS: Forty-four patients (8.9%) experienced a recurrence in the neck and one patient died. Recurrences were established histopathologically in 26 and by a new uptake in DxWBS in 16 cases. A combination of neck US and high Tg revealed 42 of 44 recurrences. Of 993 ultrasonographies, 149 led to FNAB and 28 FNABs to surgery. Serum Tg was elevated 173 times, indicating a recurrence in 23 patients.
CONCLUSIONS: Although longer follow-up is still needed, monitoring low-risk differentiated thyroid carcinoma patients with neck US and T(4)-suppressed Tg appears to be safe, provided radioactive iodine remnant ablation has been given and a low-alarm threshold for Tg indicating further evaluation, is used. The number of additional studies caused by this surveillance paradigm was reasonable. DxWBS was helpful in selected cases. Comparative studies are warranted to show how much rhTSH-stimulation tests add to this surveillance scheme.