11
Table 5. Clinical Implications of Response To Therapy
Re-Classification in Differentiated Thyroid Cancer
Patients Treated With Total Thyroidectomy and RAI
Remnant Ablation
Category Definitions Clinical Outcomes
Management
Implications
Excellent
Response
Negative imaging and either
Suppressed Tg <0.2 ng/mL
a
OR
TSH stimulated Tg<1 ng/mL
a
• 1-4% recurrence
• <1% disease
specific death
An excellent
response to therapy
should lead to an
early decrease in
the intensity and
frequency of follow
up and the degree of
TSH suppression.
Biochemical
Incomplete
Response
Negative imaging
AND
Suppressed Tg >1 ng/mL
a
OR
Stimulated Tg >10 ng/mL
a
OR
Rising Tg Ab levels
• At least 30%
spontaneously
evolve to NED
• 20% achieve
NED after
additional
therapy
• 20% develop
structural disease
• <1% disease
specific death
If associated with
stable or declining
serum Tg values,
a biochemical
incomplete
response should
lead to continued
observation with
ongoing TSH
suppression in most
patients. Rising
Tg or Tg antibody
values should
prompt additional
investigations
and potentially
additional therapies.
