Plasma thyroglobulin and neck ultrasound allow the detection of residual or
recurrent disease in the majority of post-operative differentiated thyroid cancer
patients. The two tests are complimentary to each other and are better than either test
alone. Neck ultrasound is superior to neck palpation and allows morphological
differentiation of benign from suspicious cervical lymph nodes. A baseline neck
ultrasound is performed at 3-6 months post-operatively to examine the neck for
persistent thyroid cancer and to plan for radioactive iodine ablation in patients at an
increased risk for thyroid cancer recurrence. Neck ultrasonography is repeated
periodically thereafter to exclude recurrent disease. Suspicious cervical lymph nodes
and thyroid bed lesions can be biopsied under ultrasound guidance, and a needle
washout obtained for measurement of thyroglobulin in patients with differentiated
thyroid cancer and calcitonin in medullary thyroid cancer. Neck ultrasound also allows
the examination of other anterior neck structures such as muscle and blood vessels for
invasive disease and can be used to mark the location of suspicious nodes pre- or intraoperatively.
In patients with elevated plasma tumour markers and negative neck
ultrasound, whole body iodine scan or cross-sectional imaging may be useful.
Keywords: Anti-thyroglobulin antibody, Clinical neck palpation, Calcitonin,
Cytopathology, Metastatic cervical lymph node, Neck ultrasound, Positron
emission tomography, Recurrence of differentiated thyroid cancer,
Thyroidectomy, Thyroid cancer, Thyroglobulin, Thyroid bed, Thyroid tissue
remnant, Whole body iodine scan, Whole body single photon emission
tomography.
