1) Thyroid cancer in children has distinct characteristics compared to adults, with papillary carcinoma being much more common and follicular carcinoma rarer. Children also often present with more advanced disease. 2) Fine needle aspiration is important for diagnosis, but distinguishing benign from malignant follicular lesions can be difficult. 3) Treatment involves surgery, with total thyroidectomy recommended for high-risk cases and lobectomy sometimes sufficient for low-risk papillary carcinoma under 1cm. 4) Outcomes are generally excellent even with metastases, though management challenges exist due to lack of prospective trials. Careful long-term follow-up is important.

1. Thyroid Malignancies
In Children
Bhaskar N. Rao, M.D.
St. Jude Children’s Research
Hospital
10/03

2. THYROID CANCER
Staging
T0 No evidence of tumor
T1 tumor <1 cm
T2 tumor 1-4 cm
T3 tumor >4 cm
T4 tumor any size beyond capsule
N0 No nodal mets
N1 regional nodes
N1a ipsilateral cervical nodes
N1b bilateral or mediastinal
M0 N0 distant mets M1 distant mets

3. THYROID CANCER
Staging (Pap/follicular)
Age <45 Stage 1 Any T Any N M0
Age >45 Stage 1 T1 N0 M0
Stage 2 T2/T3 N0 M0
Stage 3 T4 or N0 M0
T1-4 N1 M0
Stage 4 T1-4 Any N M1
Anaplastic All cases are stage IV
Stage 1 T1 N0 M0
2 T2-4 N0 M0
3 Any T N1 M0
4 Any T Any N M1
Staging (Medullary)

4. Thyroid Cancer
Epidemiology
• 20,000 new cases/year in the US
– more often in women and whites
• Peak incidence: 40 (women), 60 (men)
• Lifetime risk: 1%
• Histology: Papillary - 80%
Follicular - 11%
Hurthle cell - 3%
Medullary - 4%
Anaplastic - 2%

5. Thyroid Cancer
Epidemiology - Children
• Low incidence in childhood
– 1.5% of all tumors < 15 years
– peak 7-12 years
– 10% of all head and neck cancer
– 10% are diagnosed in childhood
– 2/3 in girls
• Indolent course, even with metastases
– Survival > 90%
• Up to 8% of secondary pediatric cancers

6. Thyroid Cancer
Epidemiology - Children
• Low dose RT used for Thymus, Hemang, Acne
• Average dose 600cgy. One million people at risk
• One fourth will develop nodules
• Most (75%) Benign Hyperplasia, Adenoma, Fibrosis
• Treatment Lobectomy – Post-op Hormones

7. Thyroid Cancer
Epidemiology - Children
• Increased risk of Carcinoma
• Most are Papillary Carcinomas (20-50%)
• Latency median 20 years
• Most are multicentric, with lymph nodes
• Other tumors – Salivary Gland, Parathyroid, Bone,
Soft tissue Sarcomas, Thyroid lymphomas

8. Thyroid Cancer Histology
• Papillary
– 80% incidence increases with younger age
– High incidence of bilaterality, regional nodes
• Follicular
– Rare in children
– Distinguished from adenoma by vascular or capsular invasion
• Medullary
– arise from calcitonin-secreting c-cells
• Anaplastic
– Extremely aggressive, high mortality
Tumor Variable Affecting Prognosis
• Histology
• Size
• Local invasion
• Lymph node
• Distant metastases

9. Thyroid Cancer
Epidemiology - Children
• Thyroid cancer has proven to be a common SNM
• Between 1980 & 1987 58 centers in Europe reported
239 SMN’s
• 18 of 239 (7.5%) were thyroid cancers
• 6 / 18 primary was Hodgkins all received chemo +
RT (25-42gy)
• 7 / 18 primary was ALL all had CS RT (18-24gy)
• 2 Ewings, 1 Wilms, 1 NB and 1 NPC

10. Thyroid nodules
• By far most thyroid nodules are benign
and are either colloid nodules,
adenomas or manifestations of
thyroiditis
• They may be cystic or solid
• Most cystic are generally benign
(degenerated colloid)
• They may be toxic or non toxic
Thyroid Cancer
Pediatric vs. Adult
• Thyroid masses more likely to be cancer
– 50% of solitary nodules are malignant
– More often larger, multicentric
• Higher rate of metastasis at diagnosis
– regional lymph nodes: 65% (35% adult [papillary])
– distant: 20% (10% adult [follicular])
• Higher rate of recurrence
– 40% <20y (also >60y); 20% adults
– 80% locoregional, 20% distant (similar)

11. Thyroid Cancer
Diagnostic Imaging
• Traditionally I131 Now I123 or Technitium scans
• Nodules hyperfunctional (hot) with increased avidity
• Functional cold same as rest of gland
• Minimum 1 cm diameter for cold nodules
• Hot functional nodules practically benign
• Cold – incidence of malignancy higher

12. Thyroid Cancer
Diagnostic Imaging
• USG – differentiate multinodular vs solitary
• CT or MRI – invasive lesion or sub-sternal location
• Specific / sensitive is F.N.A.
• Malignant, suspicious, benign or inadequate
• If it is suspicious I123 , hot, rarely malignant
cold 20% or higher

13. Thyroid Cancer
Pediatric vs. Adult
• Better overall survival
– >95% for children
– 75-90% for adults
• Better survival with metastases
– 86% of children
– 32% of adults
Thyroid malignancies in pediatric population – how is it different?
• Papillary ca. constitutes 85-90% of all malignant lesions with medullary
second, forming 5%
• Unlike adults follicular not as common and when present it is usually in the
adolescent population
• Thyroid lymphomas and metastasis are hardly ever seen in pediatric
population
• In familial medullary ca. prophylactic thyroidectomy is done in kids before
they attain age 5yr
• PARADOX:
– often presents with extensive disease and progression or
recurrence in a significant number of patients
– is rarely fatal
• Suggests biologic rather than treatment factors have a greater
effect on outcome

14. Approach to a malignant thyroid nodule
Clinically suspicious nodule >1cm
• Increased suspicion
– Male
– Nodule > 4cm
– Age < 15 yr
– H/O XRT exposure
– H/O
• Pheochromocytoma
• Hyperparathyroidism
• Gardner’s
• FAP
• Carney’s complex
• Cowden’s syndrome
• Highly suspicious
– Rapid nodule growth
– Fixation
– Family history
– V.C paralysis
– Lymph nodes
– Neck invasion
• TSH
• FNA of nodule/ lymph nodes
• If insufficient FNA → repeat FNA (imparts 50% extra chance)
• US solid or cystic and assist in FNA and determining the size of the
nodule
• Cystic nodules may be followed

15. Thyroid Carcinoma
• Fine needle aspiration important
• Distinguishing benign/malignant follicular difficult
• Thyroid nodules containing follicular cytopathologic
features have 20-30% malignancy
• Thyroid malignancy rate is 6.8% without atypia and
44-50% with atypia
•Allows for conservative approach in selected patients

16. Thyroid Cancer
Surgical Options
• Total Thyroidectomy in patients with invasive or
metastatic or bilateral or previous RT
• For others – controversy varies with surgery and
complication rates
• Unilateral P.C. or F.C. < 1.5 cm lobectomy + isthmus
• If > 1.5 cm opposite lobe 30-80% recurrence rate is
10%
• Recurrence associated with 30% mortality with 50%
desease found in central neck
• Total Thyroidectomy recurrence less than 5%

17. recurrent laryngeal n.
sup. parathyroid

18. Thyroid Cancer
Surgery Risk vs. Benefit
• Total Thyroidectomy
– High risk groups: radiation, MTC, Anaplastic
– Simplifies use of radioiodine
– Follow thyroglobulin levels
– Increased risk without increased survival benefit
• 15% each-recurrent laryngeal nerve injury, hypoparathyroidism
• 30% higher than lobectomy

19. recurrent laryngeal n.
sup. parathyroid
Thyroid Cancer in Childhood
Challenges of Thyroid
Cancer Management
• No prospective randomized trials of treatment
• The prognosis is generally excellent

20. Thyroid Carcinoma
Minimally Invasive Surgery
Criteria by Niccoli et al. (Am J Surg, 2001)
• Nodules less than 3.5 cm
• Total thyroid volume less than 15ml
• No previous neck surgery or irradiation
• Absence of thyroiditis/invasion
• Total 336 pts. One-third total thyroidectomy
• Conversion 4.5%
Yamashita et al.
•25-30 mm transverse upper lateral neck
• Total 39 pts. Recurrent nerve injury one
• Tumor size 1.9 – 5.5 cm
• Surgery 56 mm (36-90 minutes)
• Other approaches described Axillary Approach

21. Approach to a thyroid nodule
(Papillary on FNA-high risk)
• Papillary ca. (dx. By FNA) and high
risk
• Total thyroidectomy
• If L.N positive
– Central neck disec
– Lateral neck disec.(level II-IV,
sparing spinal accessory nerve,
int. jugular, SCM)

22. Management post lobectomy for
papillary (<1cm- low risk)
• Their recurrence and cancer specific
mortality rates are almost zero
• Supress TSH with thyroxine
• Tg and whole body I scan are insensitive
• Physical exam with local neck US seem to
be the best suggested follow up

23. Follow up papillary
• P/E q 3-6 mo for 2yrs with periodic US
• Tg @ 6 & 12mo then annually
• RI scans q 12mo
• Periodic CXR/ CT chest
• For locoregional recurrences → surgery
followed by RI
• Tg rise >10ng/ml → RI therapy with 100-
150mCi

24. Thyroid Carcinoma
• Follicular carcinoma represent 10-20%
• Prognostic factors include size, age, metastasis
• Witte et al., report L.N., size, stage, mets, sex
Advised total thyroidectomy + L.N. dissection and
ipsilateral or bilateral L.N. dissection for T3, T4
Follicular lesion
TSH high → Thyroxine/Surg
Follicular TSH normal → Surgery
TSH low → Thyroid scan hot
cold

25. Approach to thyroid nodule
(Follicular on lobectomy)
Invasive
Follicular carcinoma
on lobectomy
Further local and metastatic
work up
< 1cm → observe/ re-
resect
> 1 cm → completion
thyroidectomy
followed by I 131

26. Approach to a thyroid nodule
Medullary carcinoma
Medullary on FNA
• Calcitonin levels
• CEA
• Pheo screening
• Serum calcium
• Screen for RET proto-
oncogene
• Neck US