Prospective randomized open phase III non-inferiority trial in cT1bT2N0 papillary thyroid carcinoma comparing: total thyroidectomy alone (experimental group) versus total thyroidectomy + Prophylactic Neck Dissection PND (reference group).

Pre-registered patients will be randomized before surgery for tumors with class-6 cytology (Bethesda) or in the operating room after confirmation of malignancy by frozen section analysis for tumors with class-5 cytology.

Inclusion Criteria:

1. Thyroid nodule measuring 11-40 mm on ultrasound (cT1bT2)

   • AND with fine-needle aspiration biopsy (FNAB) cytology in favor of "papillary thyroid carcinoma" (Type 6 according to the Bethesda classification (or BRAF mutation found on cytology analysis) (Appendix 2)
   • OR with FNAB cytology "suspicious for malignancy" (Type 5 according to the Bethesda classification). In this latter case, randomization will be performed if confirmation of papillary carcinoma on intraoperative frozen section analysis

2. cN0: absence of lymph nodes suspicious for malignancy on pre- operative ultrasound performed by the center's designated radiologist according to a standardized report

3. Absence of a medical contra indication to performing a total thyroidectomy with or without bilateral prophylactic neck dissection of the central compartment

4. Women of childbearing potential should have a negative pregnancy test (serum or urine) before any radioiodine administration. Sexually active patients must agree to use an effective method of contraception or to abstain from sexual activity during the study and for at least 6 months after last dose of radioiodine.

5. Patient affiliated to a social security regimen or beneficiary of such regimen

6. Patients age ≥ 18 years old, french-speaking

7. Patients should understand, sign and date the written informed consent form prior to any protocol specific procedures. Patients should be able and willing to comply with study visits.

Exclusion Criteria:

1. Tumors > 40 mm (cT3) or ≤ 10 mm
2. Tumors with extrathyroidal extension suspected or obvious on the pre-operative work-up or intra-operatively (cT3T4)
3. Metastatic neck lymph nodes or suspicious neck nodes on pre- operative ultrasound (cN1); for suspicious nodes, FNAB cytology and thyroglobulin assay on the needle washout fluid will be performed
4. Metastatic neck lymph nodes found during the thyroidectomy and confirmed with intra-operative frozen section analysis
5. Medullary thyroid carcinoma on FNAB cytology and/or with basal serum calcitonin >50 pg/ml
6. Preoperative or intra-operative suspicion of non-papillary thyroid carcinoma or aggressive histopathological subtype or poorly differentiated carcinoma
7. Distant metastases (M1) apparent pre-operatively (found due to symptoms or fortuitously; no specific pre-operative work-up will be performed, however, in accordance with current clinical practice)
8. Recurrent nerve paralysis visualized on systematic pre-operative laryngoscopy and/or abnormal preoperative serum calcium
9. Pregnant or breast feeding women
10. Participation in another therapeutic clinical trial within one year from study entry
11. Patient under guardianship or deprived of his liberty by a judicial or administrative decision or incapable of giving its consent