Diagnostic Accuracy of rhTSH Test with Neck Ultrasonography in Differentiated Thyroid Cancer Follow-up

Serum thyroglobulin levels measurement after injection of recombinant human thyrotropin (rh-TSH) represents the most important advance in the follow-up of patients with differentiated thyroid cancer, obtaining TSH elevation without L-thyroxine withdrawal, avoiding marked hypothyroidism symptoms. During a 4-yr period (2004-2008), 66 consecutive patients with DTC (59 papillary and 7 follicular carcinomas) were examined after rh-TSH Tg test and neck ultrasonography. In all patients basal Tg was <0.25 ng/ml. In twelve (18.5%) examined patients rh-TSH Tg was >0.25 ng/ml, and in seven (58.3%) of these was demonstrated persistent or recurrent disease. These data indicate that rhTSH-Tg >0.25 ng/ml should be considered diagnostic for persistent or recurrent disease and suggests further exams (neck ultrasonography, whole body scan or cytology) to localize the disease. Furthermore, neck ultrasonography has demonstrated high accuracy in detecting lymph nodal metastases and should be always combined with rh-TSH test.