Inclusion Criteria:

1. Patients with differentiated thyroid cancer (papillary, follicular or with Hurthle
cells) in the absence of aggressive histological subtypes (poorly differentiated,
tall-clear-cylindric cell, diffuse sclerosing or with an anaplastic component)

2. Patients having undergone a total thyroidectomy with complete (R0) tumor resection,
with or without lymph node neck dissection

3. Surgery performed 2 to 4 months before inclusion

4. Patients with low risk of recurrence: pT1amN0 or pT1amNx with a sum of the size of
the lesions above 1 cm and equal to or less than 2 cm, or pT1bN0 or pT1bNx (TNM 2010
classification). (Patients with less than 6 lymph nodes in the neck dissection will
be classified as Nx)

5. Post-operative neck ultrasound (performed 2 to 4 months after surgery) showing the
absence of abnormalities in the lateral lymph node compartments, or if abnormalities,
no lymph nodes with abnormal cytology and/or thyroglobulin concentration in the
aspirate fluid > 10 ng/mL

6. Age >=18 years

7. Performance status of 0 or 1

8. Patients who signed the informed consent

9. Patients who can be followed-up annually during 5 years in order to assess the
objectives of the study

10. Women of childbearing age should have a negative pregnancy test before any
radioiodine administration

11. Both patients with or without thyroglobulin antibodies are eligible

Exclusion Criteria:

1. Patients having undergone less than a total thyroidectomy

2. Patients with aggressive histotype (poorly differentiated, tall-clear-cylindric cell,
diffuse sclerosing, or with an anaplastic component)

3. Patients having undergone surgery less than 2 months or more than 4 months before
inclusion

4. Patients with cancer classified as pT1a unifocal (in which ablation is not
necessary), or pT1N1, pT2, pT3, pT4 or N1 (who have a higher risk of recurrence)
(classification TNM 2010)

5. Patient with known distant metastasis

6. Abnormal post-operative neck ultrasound of the lateral lymph node compartments

7. Patients with another malignancy not in remission for at least 2 years (except for in
situ cervix uterine cancer, basocellular skin cancer)

8. Patients with a recent history of drugs affecting thyroid function, including
injection of radiocontrast agents during the last 8 weeks.

9. Patients previously treated with radioactive iodine or who previously underwent a
whole body scan with radioactive iodine

10. Pregnant or breast feeding women

11. Subject with any kind of disorder that may compromise his/her ability to give written
informed consent and/or to comply with study procedures