9
D) In patients with DTC of any risk level with significant co-
morbidity that may preclude thyroid hormone withdrawal prior to
iodine radioiodine administration, recombinant human thyrotropin
preparation should be considered. Significant co-morbidity may
include:
a) a significant medical or psychiatric condition that could be acutely exacerbated with
hypothyroidism leading to a serious adverse event, or
b) inability to mount an adequate endogenous TSH response with thyroid hormone
withdrawal. (SR-L)
55. A) If radioactive iodine remnant ablation is performed after total
thyroidectomy for ATA low risk thyroid cancer or intermediate risk
disease with lower risk features (i.e., low volume central neck
nodal metastases with no other known gross residual disease nor
any other adverse features), a low administered dose activity of
approximately 30 mCi is generally favored over higher administered
dose activities. (SR-H)
B) Higher administered activities may need to be considered for
patients receiving less than a total or near-total thyroidectomy
where a larger remnant is suspected or where adjuvant therapy is
intended. (WR-L)
63. A) In ATA low-risk and intermediate-risk patients who have had
remnant ablation or adjuvant therapy and negative cervical US,
serum Tg should be measured at 6–18 months on thyroxine therapy
with a sensitive Tg assay (<0.2 ng/ml) or after TSH stimulation to
verify absence of disease (excellent response). (SR-M)
B) Repeat TSH stimulated Tg testing is not recommended for
low and intermediate risk patients with an excellent response to
therapy. (WR-L)
C) Subsequent TSH stimulated Tg testing may be considered
in patients with an indeterminate, biochemical incomplete
or structural incomplete response following either additional
therapies or a spontaneous decline in Tg values on thyroid hormone
therapy over time in order to reassess response to therapy. (WR-L)
The highest degrees of sensitivity for serum Tg are noted following
thyroid hormone withdrawal or stimulation using rhTSH.
67. A) Diagnostic WBS, either following thyroid hormone withdrawal or
rhTSH, 6–12 months after remnant ablation adjuvant RAI therapy
can be useful in the follow-up of patients with high or intermediate
risk (higher risk features) of persistent disease and should be done
with
123
I or low activity
131
I. (SR-L)
