Northeast Florida Medicine
Vol. 66, No. 2 2015
33
Pediatric Oncology
also noted a high recurrence rate of 27.6 percent in a group
of 740 pediatric patients from Belarus.
19
Treatment:
Role of Surgery
Reported tumor and patient characteristics at presentation
that encourage a more aggressive surgical approach to DTC
in children include a high incidence of multifocality (30-66
percent), gross tumor invasion/extra-thyroidal extension (up to
47 percent), nodal metastases (33-80 percent), distantmetasta-
ses (5-25 percent) and young patient age (<10-16 years).
9,20-26
An understanding of the pattern of lymphatic spread of DTC
has now been well established with the central compartment
(Level VI) nodal basin most commonly involved, followed by
lateral compartment (Levels III, IV) and, least commonly, the
posterior triangle or mediastinal nodal areas (Levels V, VII).
26-28
Most centers currently advocate total thyroidectomy with, at
a minimum, central compartment dissection, although the
type of surgical procedure (total versus lobectomy only) has
not been consistently shown as a significant factor in DFS
(disease free survival). A recent report by Handkiewicz-Junak
on 235 children with DTC showed that total thyroidectomy
significantly decreased the incidence of tumor bed recurrence
(p<.001) and inadequate nodal dissection (berry picking versus
MRND) was predictive of nodal recurrence (p=0.02).
21
In contrast, based on increased surgical morbidity with
aggressive surgical intervention, a lesser approach with thy-
roid lobectomy of the affected side only has been proposed.
29
Massimino studied the impact of radical (total thyroidectomy
andMRND) andconservative (lobectomy and selective lymph
node dissection) among 42 patients with DTC and found no
significant difference in PFS (progression free survival). The
study also noted a very high incidence of surgical morbidity
in the radically treated group (30 percent permanent hypo-
parathyroidism, 10 percent RLN injury). Furthermore, they
discount the significance of microscopic subclinical disease
in either the opposite lobe or cervical nodes and advocate
postoperative TSH suppression only without RAI therapy.
The reported incidence of permanent hypoparathyroidism
ranges from 0-32 percent and for recurrent laryngeal nerve
injury 0-40percent.
4,21,27,30,32,33
In a large series (n=215) treated
for DTC over a 68 year period, Hay showed a marked decline
in complications rates, reporting no permanent hypopara-
thyroidism and one RLN injury in the most recent 27 cases,
despite an aggressive surgical approach.
32
Hallwirth in a series
of 18 patients reported no incidence of permanent hypopara-
thyrodism and three (17 percent) in whom the nerve was
deliberately sacrificed due to tumor encasement.
33
Accepted
adjuncts to reduce the incidence of surgical complications
include autotransplantation of visibly ischemic parathyroid
tissue and avoiding sacrifice of the RLN, despite tumor
encasement. Finally, the expertise of the thyroid surgeon is
critical to realize optimal results.
1,4
Role of Radiation Therapy
Postoperative radioactive iodine (RAI) therapy is given to
ablate residual disease and thyroid tissue in the thyroid bed,
cervical nodal disease and as primary treatment of distant
metastatic disease. Dosing is most commonly determined
by the amount of residual cervical disease (thyroid bed or
nodal) or the presence of distant metastases as determined by
postoperative whole body scan (WBS). In addition, thyro-
globulin (Tg) levels can guide dosing decisions. Iodine-131 is
given as a fixed dose based on the amount of disease (thyroid
bed/remnant ablation 30-100mCi, nodal disease 100-200
mCi, multiple pulmonary metastases 175-200mCi), though
dosimetry-guided techniques, body surface area or weight-
based dosing can be used.
1
Hematologic toxicity, second malignant neoplasms (GI
tract, bladder, breast, salivary gland, leukemia), xerostomia,
sialadenitis and infertility have been reported with RAI ther-
apy.
4,34-36
Pregnancy is to be avoided within one year of RAI
use. Radiation induced pulmonary fibrosis in the presence
of extensive pulmonary disease with high Iodine-131 activity
retention rarely occurs.
4,37,38
Total doses should be limited
with general guidelines favoring approximately 500mCi in
children and 800mCi in adolescents.
4,38
Caution should be
exercised as accumulative dose increases, while attempting to
achieve complete remission in partial responders.
Chow and associates in a series of 56 patients without dis-
tant metastases at presentation, found improvement in local
recurrence free survival at 10 years with RAI (72 versus 86.5%,
p=.04).
39
Their criteria for RAI therapy included all tumors
> 1cm, extra-thyroidal extension, residual neck disease on
WBS, nodal or distant disease. A direct correlation with the
amount of residual disease, in the absence of nodal or distant
metastases at presentation, and response to RAI has been
clearly demonstrated.
40,41
Correlation was also found between
the amount of disease at presentation and the number of RAI
treatments needed to achieve remission.
42
In the presence of
pulmonary metastases, RAI achieved complete response in 47
percent of 112 patients pooled from nine published studies.
37
LaQuaglia reported on 83 patients with pulmonarymetastases
from 15 treatment centers and found progression-free survival
of 76 percent at five years and 66 percent at 10 years, and 100
percent overall survival.
43
A 2013 report by Reiners on 100
Chernobyl-exposedBelaruschildrenwithpulmonarymetastases
noted a 46 percent complete response to RAI.
44
Furthermore,
Reiners noted that in 18 partial responders, 10 years post RAI
therapy, a continued yearly decline inTg levels was noted with
no progressive lung disease or cases of pulmonary fibrosis.
44
Though final recommendations for RAI use in childhood
DTC vary, current practice is to treat all with RAI with
