Follow-up of Hürthle Cell Carcinoma

Introduction to Follow-up Strategies

The American Thyroid Association recommends annual measurement of thyroglobulin (Tg) and anti-Tg antibodies, neck ultrasound, and maintenance of TSH in the low-normal range (0.5-2 mIU/ml) for patients with excellent response to initial treatment 1, 2
The European Thyroid Association suggests that the follow-up protocol depends critically on the response to treatment evaluated in the first 1-2 years after radioactive iodine therapy 1, 2

Patients with excellent response (stimulated Tg < 1 ng/ml, negative ultrasound) should undergo annual monitoring with basal Tg and anti-Tg antibodies measurement 1, 2
Neck ultrasound should be performed as needed, based on Tg and anti-Tg antibodies levels 1, 2
TSH should be maintained in the low-normal range (0.5-2 mIU/ml) with levothyroxine therapy 1, 2
The risk of recurrence in these patients is less than 1% at 10 years, allowing for a less intensive follow-up approach 3

Patients with incomplete or indeterminate response should undergo Tg and anti-Tg antibodies measurement every 6-12 months 1, 2
Neck ultrasound should be performed every 6-12 months 1, 2
Rising Tg or anti-Tg antibodies levels require further imaging investigations 1, 2
Mild TSH suppression (0.1-0.5 mIU/ml) should be considered 1, 2

PET-CT with FDG is indicated as the first-line isotopic imaging for disease refractory to radioactive iodine 1, 2
PET-CT has a sensitivity of 94% and specificity of 80-84% 1, 2
CT is preferred for neck and chest imaging, while MRI with contrast is appropriate for neck, liver, bones, and brain 1, 2

Patients with excellent response and low risk should have TSH in the normal range (0.5-2 mIU/ml) 1, 2
Patients with incomplete or indeterminate response should have mild TSH suppression (0.1-0.5 mIU/ml) 1, 2
Excessive TSH suppression should be avoided to prevent osteoporosis, especially in postmenopausal women 4

At 8 years after initial treatment, patients with excellent response should undergo annual physical examination, basal Tg measurement every 12-24 months, and neck ultrasound as needed 1, 2, 3
Most local recurrences develop within the first 3 years, but late recurrences can occur even 20 years after initial treatment 3