131 IODINE TREATMENT FOR THYROID CANCER IN CHILDREN

131 – IODINE TREATMENT

FOR THYROID CANCER

IN CHILDREN

Jasna Mihailović, MD, PhD, Prof

Head, Department of Nuclear Medicine

Oncology Institute of Vojvodina

Sremska Kamenica, Serbia

Speaker Name: Jasna Mihailovic

I have no financial interests or relationships to disclose with regard to the

subject matter of this presentation.

Declaration of

Financial Interests or Relationships

Juvenile DTC - Introduction

Juvenile differentiated thyroid carcinoma (JDTC) is a rare

malignancy (0.5%–3% of all malignant tumors in

childhood).

DTC incidence of 7% and 10%, is reported in prepubertal

and adolescent period, respectively.

The Serbian Cancer Registry: 44 newly diagnosed cases of

DTC in ≤19 y old patients (1999-2012); Female-to-male

ratio = 3.9:1.

Juvenile DTC - Introduction

Aggressive initial presentation - involvement of cervical

lymph nodes and frequently distal metastases.

Usually, juvenile DTC has a good clinical outcome. 98% of

disease-specific survival after 30 years following the initial

surgery (Hay 2010).

High recurrence rate.

Juvenile DTC

Recurrent disease - Prognostic factors

1. Initial treatment - Extent of surgery and RAI

Less radical primary surgery increases relapse rate.

Ten times higher recurrence (range 2.3-39.1) among

children who undergo less extensive surgery (Jarzab 2000).

Recurrence rate obtained after hemithyroidectomy was

higher than after TTx (38% vs.7.5%, respectively)

(Popovitzer 2006).

Patients postoperatively treated with RAI show lower risk for

recurrence that patients who did not receive ablation

(Jarzab 2000, Chow 2004, Mihailovic 2014).

Juvenile DTC

Recurrent disease - Prognostic factors

2. Age

Not a significant factor (Handkiewicz-Junak 2007, Palmer 2005).

Age at diagnosis - significant patient-related factor in

univariate anlaysis (Jarzab 2000, Mihailovic 2014).

Higher risk of relapse in younger children ( ≤10 yr old) (Mazzaferri 1994, Jarzab 2000, Mihailovic 2014).

3. Tumor multifocality

Patients with multifocal tumors - higher recurrence

rate than those with unifocal tumors (Lin 2009, Mihailovic 2014).

Juvenile DTC - Treatment

Usually treated the same way as in adults.

Recently, in 2015, the ATA Guidelines Task Force on

Pediatric Thyroid Cancer released Management

Guidelines for Children with Thyroid Nodules and

Differentiated Thyroid Cancer (Thyroid 2015).

Juvenile DTC - Treatment

RAI activity:

Body weight (1.85 – 7.4 MBq/kg)

Patient's age

1/3 adult activity to 5-yr old

1/2 adult activity to 10-yr old

5/6 adult activity to 15-yr old

24h-RAIU and by BW

<5% uptake to 50 MBq/kg

5-10% uptake to 25 MBq/kg

10-20% uptake to 15 MBq/kg

Juvenile DTC - Treatment

I-131 activity for ablation: longer life expectancy, higher

sensitivity to possible complications after treatment,

smaller body and organ size.

In patients with extensive lung metastases, there is

concern about high radiation absorbed dose to the

lungs and pulmonary fibrosis.

DOSIMETRY/ REDUCED I-131 ACTIVITY!

There are no effects on subsequent fertility and

pregnancy outcome and no secondary malignancies

(La Quaglia 1988, Chow 2004, Mihailovic 2014).

SERBIAN EXPERIENCE

Mihailović J, et al. Recurrent Disease in Juvenile Differentiated Thyroid Carcinoma:

Prognostic Factors, Treatments, and Outcomes. J Nucl Med 2014.

Period = January 1977 - December 2012

1,502 DTC patients were treated with I-131

(53 JDTC patients)

51 patients without a history of prior radiation were

retrospectively reviewed (32 girls and 19 boys)

(mean age, 16.5 yrs; range, 7–20 yrs)

INITIAL TREATMENT

Surgical treatment differed among hospitals.

RAI Ablation

The Oncology Institute of Vojvodina was the only facility

in Serbia for RAI through 2006.

RAI ablation was administered 4 weeks after withdrawal

of L-thyroxine (T4) therapy.

Whole-body or blood dosimetry calculations were not

performed.

In prepubertal children = BW (50–100 MBq/kg)

After puberty = 3.7-5.6 GBq

(3.7 GBq was used in N0M0; 5.6 GBq in N1M0/N1M1)

Response to the initial treatment

RESULTS

Recurrence developed in 11/51 (21.6%) patients.

The median appearance time is 52 mo (range, 12–180

mo).

Prognostic factors with no influence to the recurrence:

sex, nodal metastases at presentation, distal metastases at

presentation, histologic type of the tumor, T stage, and

clinical stage (P = 0.180, P = 0.786, P = 0.796, P = 0.944,

P = 0.352, and P = 0.729, respectively).

Probability of recurrence

5 years = 16.7%

10 years = 22.3%

15, 25 years = 33.3%

P = 0.0001

Influence of type of the initial treatment

Influence of patient’s age at diagnosis

P = 0.001

Influence of tumor multifocality

P = 0.011

RESULTS - Recurrence

Localization

Thyroid bed = 1 patient

Cervical LN = 5 patients

Distant sites (lungs) = 3 patients

Combined (lungs and brain; cervical LN and lungs) = 2

patients

Time of appearance

1 patient = after 4 and 12 years

1 patient = after 7, 22, and almost 25 years

TREATMENT OF RECURRENT

DISEASE

CASE 1

14-years old girl; after primary surgery+EBRT (115 Gy)+ 4xRAI;

I-131 WBS PA; TSH, 40mU/l; Tgb, 850μg/L

two years later, I-131 WBS AP; TSH, 45mU/l; Tgb, 13μg/L

FINAL OUTCOME

During the FU 25/36 patients with initial CR did not relapse;

1 patient with CR died from another cause of death.

14 patients with initial PR were retreated; outcome:12 patients = CR,

1 patient with PD = CR.

11 female patients (CA, 3.7–40 GBq) ultimately had children

(8 women delivered 2 children, and 3 women had 1 child)

CONCLUSION

TTx followed by RAI appears to be an appropriate initial

treatment.

Younger age at diagnosis, tumor multifocality,

insufficient primary surgery, and lack of radioiodine

ablation are risk factors for recurrent disease in JDTC.

Recurrent disease should be treated with surgery or

radioiodine treatment until remission.

Both initial treatment with radioiodine and retreatment

with radioiodine are safe, with no adverse effects on

fertility or secondary malignancy.