What are the NCCN and ATA guidelines on radioiodine therapy for follicular thyroid carcinoma (FTC)?

Updated: Jun 18, 2020
  • Author: Luigi Santacroce, MD; Chief Editor: Neetu Radhakrishnan, MD  more...
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NCCN guidelines recommend radioiodine (131I) therapy if any of the following are present [1] :

  • Extrathyroidal extension
  • Tumor >4 cm in diameter
  • Postoperative unstimulated thyroglobulin (Tg) level >5-10 ng/mL

Radioiodine therapy is not recommended if all of the following are present [1] :

  • Classic papillary thyroid carcinoma (PTC)
  • Primary tumor <1 cm
  • Intrathyroidal tumor
  • Unifocal or multifocal tumor
  • No detectable anti-Tg antibodies
  • Postoperative unstimulated Tg< 1 ng/mL

Radioiodine therapy is selectively recommended if any of the following are present when the combination of clinical factors predicts a significant risk of recurrence: [1]

  • Primary tumor 1-4 cm
  • High-risk histology
  • Lymphovascular invasion
  • Cervical lymph node metastases
  • Macroscopic multifocality (one focus >1 cm)
  • Presence of anti-Tg antibodies
  • Postoperative unstimulated Tg </ul>

    The ATA recommends radioiodine therapy for all patients if any of the following are present: [37]

    • Distant metastases
    • Extrathyroidal extension of the tumor regardless of tumor size
    • Primary tumor size >4 cm even in the absence of other higher-risk features.

    Radioiodine therapy is not recommended for patients with unifocal cancer 37</ref>

    Radioiodine therapy is also recommended for selected patients with 1-4 cm thyroid cancers confined to the thyroid who have documented lymph node metastases or other higher risk features, when the combination of age, tumor size, lymph node status, and individual histology predicts an intermediate to high risk of recurrence or death from thyroid cancer. [37]

    The ATA and NCCN guidelines recommend treatment with levothyroxine to suppress thyroid-stimulating hormone (TSH) levels. Degree of suppression is based on risk, as follows  [37, 1] :

    • Low-risk patients - Maintenance of the TSH at or slightly below the lower limit of normal (0.1 to 0.5 mU/L)
    • Intermediate-risk patients - Initial TSH suppression to below 0.1 mU/L
    • High-risk patients - Initial TSH suppression to below 0.1 mU/L

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