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Vol. 66, No. 2 2015
Northeast Florida Medicine
Pediatric Oncology
initial dose based on amount of disease at presentation and
accumulative dose based on response.
4,35,45
As previously
discussed, children stratified as ‘high-risk’ warrant aggressive
therapy that includes RAI.
Suppression and
other Adjuvant Therapy
Thyroid hormone suppression therapy is indicated in all
children with DTC following initial surgical therapy. The
goal is to suppress TSH production levels (<0.1 uU/ml
or lower) guided by the patient’s extent of disease. When
complete response (no detectable disease) is achieved,
suppression can be relaxed (goal TSH<.5uU/ml). Potential
adverse effect on bone density has been raised. Additional
therapeutic options including external beam radiation,
aggressive resection of adjacent organs (trachea, esophagus,
larynx), radiofrequency thermal ablation and cytotoxic
chemotherapy (cis-platinum, adriamycin, taxol-based
regimens), at most, have a limited role in palliation.
4
Surveillance
Detecting persistent or recurrent disease requires close
and long-term follow-up. Physical examination of the neck,
neck US, WBS and measurement of Tg levels are the main-
stays for detecting disease. Scans are obtained following a
four to six week period of thyroid hormone deprivation or
after recombinant rhTSH administration. The latter avoids
the period of hypothyroidism often poorly tolerated by the
patient. Tg levels are obtained at baseline and following
rhTSH stimulation. Concomitant measurement of Anti-Tg
levels is required since they can falsely elevate measured Tg
levels. A thorough multifaceted approach to monitoring for
recurrence is provided by Rachmiel and includes testing every
three months for two years and then at gradually increasing
intervals.
44
A comprehensive review of follow-up of DTC in
children is providedbyDinauer andFrancis.
11
They emphasize
the importance of negative whole body scans as indicative of
remission and caution against over-emphasis onTg elevation
alone post-therapy. Treating for the latter alone may lead to
over-treatment and excessive RAI dose accumulation.
11
Medullary Thyroid Cancer
Patients presenting with sporadic MTC (rare in children)
almost always have metastatic disease (nodal and/or distant)
and cannot be cured, though long-term survival can occur
following treatment. Surgery is themainstay of treatment and
curative intent, in the absence of metastatic disease, requires
a total thyroidectomy and level VI nodal dissection.
6
The
key for improving survival is either to detect the disease in
those at risk in advance of palpable disease or to optimally
remove the thyroid prior to disease occurrence. The latter is
possible only inpreviously identified kindreds withhereditary
MTC (usually MEN2 syndromes versus familial MTC).
Genetic testing of these families detects the specific RET
proto-oncogenemutation responsible forMTCand allows for
prophylactic total thyroidectomy at an early age (< 6mths of
age, <5yrs, <10yrs) based on the specific mutated codons.
1,46
Thus, surgery occurs at a time when C-cell hyperplasia has
not yet advanced to MTC and is curative.
After surgery for clinical MTC, patients are followed
with calcitonin levels and CEA levels at 3-6 mth intervals
and imaged if recurrent disease is suspected. Adjuvant
therapeutic options for recurrent/persistent disease include
external beam radiation, chemotherapy and recently Van-
detanib, a RET kinase inhibitor.
1
Case Scenarios
Case 1:
9 year old boy with 1.5cm thyroid nodule positive
for PTC undergoes lobectomy with Level VI dissection, is
node negative and has no distant metastases. Based on age
alone, patient is in a high risk group. In addition, there exists
a high risk of multifocality (30-66%) in the residual thyroid.
Standard approach is completion thyroidectomy, followed
by diagnostic WBS and then 30mCi RAI therapy. Standard
monitoring for recurrence and additional RAI treatments
as needed to maximum of approximately 500mCi.
Case2:
17year oldboywithhistoryofHodgkin’s lymphoma
in early childhood presents with hoarseness, a 3cm thyroid
nodule positive for PTC and palpable level III nodes on the
ipsilateral side, no distant metastases. Given this patient’s
radiation exposure from prior cancer treatment also places
him in a high risk group.Metastatic disease is assumed present
in the palpable cervical nodes as is extrathyroidal extension.
Current most accepted treatment is total thyroidectomy
with preservation of the encased RLN preferred, level VI
nodal dissection and level II, III and IV and possible V nodal
dissection (a formal MRND) on the ipsilateral side, followed
by diagnostic WBS and then high dose (100-200mCi) RAI
therapy with additional doses till remission is achieved. Close
monitoring is especially important given this patient’s risk of
local and distant recurrence and additional RAI treatments
to achieve complete response, if possible.
Case 3:
15 year old girl presents with a 2cm PTC in the
right thyroid lobe, no palpable or US identified enlarged
nodes, and multiple bilateral pulmonary metastases. The
likelihood of achieving remission in this patient is approx-
imately 50 percent. Treatment is total thyroidectomy with
levelVI node dissection, followedby highdose (175-200mCi)
RAI therapy.Total accumulative RAI dose should not exceed
