12
Differentiated Thyroid Cancer
Figure 4. Management of the Pediatric Patient with
Known Distant Metastases
Known distant metastases
s/p therapeutic
131
I
Baseline CT chest (if not already obtained)
and/or other imaging as clinically indicated
Monitor Tg
1
on LT4
every 3-6 months
Tg
1
on LT4 rising
AND >12 months
aer initial therapy
Tg
1
on LT4 stable
or declining
123
I diagnostic whole
body scan & TSH-
stimulated Tg
1
Tg
1
on LT4 rising or
imaging documents
progression AND
>12 months aer
initial therapy
Continue
observation on
LT4 suppression;
follow imaging
No RAI
uptake BUT
response to
previous RAI
RAI uptake
AND
response to
previous RAI
No RAI
uptake AND
no response to
previous RAI
Tg
1
on LT4
remains detectable
AND >12 months
aer last therapy
Tg
1
on LT4
becomes
undetectable
Observation on
LT4 suppression;
follow imaging
Consider
131
I therapy
3
& posttreatment scan
131
I not
indicated
131
I therapy &
post-treatment scan
1
Assumes a negative TgAb. In TgAb-positive patients, the presence of TgAb alone cannot be
interpreted as a sign of disease unless the titer is clearly rising ; a declining TgAb titer would suggest
continued response to treatment.
2
Tg can transiently rise aer
131
I therapy and should not be misinterpreted as evidence for progression.
3
Repeat
131
I therapy in patients previously treated with high-dose
131
I should be undertaken only if
iodine-avid disease is suspected and if there was a previous response to therapy.
Tg
1
on LT4 stable
or declining;
disease stable
or improved on
imaging
