13
49. Initial recurrence risk estimates should be continually modified
during follow-up, because the risk of recurrence and disease specific
mortality can change over time as a function of the clinical course of
the disease and the response to therapy (SR-L)
50. A) Post-operative disease status (i.e. the presence or absence
of persistent disease) should be considered in deciding whether
additional treatment (e.g. radioactive iodine, surgery, or other
treatment) may be needed. (SR-L)
B) Post-operative serum thyroglobulin (on thyroid hormone therapy
or after TSH stimulation) can help in assessing the persistence of
disease or thyroid remnant and predicting potential future disease
recurrence. The Tg should reach its nadir by 3–4 weeks post-
operatively in most patients. (SR-M)
C) The optimal cut-off value for post-operative serum thyroglobulin
or state in which it is measured (on thyroid hormone therapy or
after TSH stimulation) to guide decision-making regarding RAI
administration is not known (NR-I)
D) Post-operative diagnostic radioiodine whole-body scans may be
useful when the extent of the thyroid remnant or residual disease
cannot be accurately ascertained from the surgical report or neck
ultrasonography, and when the results may alter the decision to treat,
or the activity of RAI that is to be administered. Identification and
localization of uptake foci may be enhanced by concomitant SPECT/
CT. When performed, pretherapy diagnostic scans should utilize
123
I
(1.5–3 mCi) or a low activity of
131
I (1–3 mCi), with the therapeutic
activity optimally administered within 72 hours of the diagnostic
activity. (WR-L)
