Imaging Off Therapy/Surveillance
Six months postoperatively, all patients without evidence of
active disease should undergo surveillance imaging with neck ultrasound,
including the surgical bed, central and lateral neck, and upper
mediastinum. 9 (GRADE C; SOR 2.0, moderate
recommendation) For patients in the ATA pediatric low risk level,
ultrasound surveillance should be performed annually for 5 years. In
both the ATA pediatric Intermediate and High-Risk groups, ultrasound
surveillance should be performed every 6-12 months for 5 years. Neck
ultrasound can continue less frequently after 5 years for the
intermediate and high-risk levels based on individual recurrence
risk.9 Thyroglobulin levels can be useful to guide
imaging assessment as a marker of residual or recurrent disease and are
performed at similar time points.
123I-diagnostic whole-body scan is recommended
in patients treated with RAI at 1-2 years following therapy. (GRADE C;
SOR 1.36, very strong recommendation)123I-diagnostic whole-body scan is also
recommended in patients with increasing thyroglobulin levels or with
concern for recurrence at other imaging. 9 (GRADE A;
SOR 1.07, very strong recommendation) Table 3 details timing of imaging
surveillance.
Are there late effects that change the goal of surveillance imaging?
Differentiated thyroid cancer recurrence has been reported several
decades after initial treatment, therefore long-term surveillance is
necessary.9 In addition, relative risk of a secondary
primary malignancy, most commonly leukemia, is increased in those
treated with RAI.39-43