What is the ATA staging for follicular thyroid cancer (FTC)?

Updated: Jun 18, 2020
  • Author: Luigi Santacroce, MD; Chief Editor: Neetu Radhakrishnan, MD  more...
  • Print
Answer

The American Thyroid Association (ATA) has published guidelines for estimating risk of recurrence in differentiated thyroid cancer after total thyroidectomy and radioactive iodine remnant ablation. The guidelines provide initial risk estimates and re-stratification based on response to initial therapy. [22]

For initial risk estimates, patients are considered at low risk if all of the following are present:

  • No local or distant metastases
  • All macroscopic tumor has been resected
  • No invasion of locoregional tissues
  • Tumor does not have aggressive histology (eg, tall cell, insular, columnar cell carcinoma, Hürthle cell carcinoma, FTC)
  • No vascular invasion
  • No  131I uptake outside the thyroid bed on the post-treatment scan, if done

Patients are considered at intermediate risk if any of the following is present:

  • Microscopic invasion into the perithyroidal soft tissues
  • Cervical lymph node metastases or  131I uptake outside the thyroid bed on the post-treatment scan done after thyroid remnant ablation
  • Tumor with aggressive histology or vascular invasion (eg, tall cell, insular, columnar cell carcinoma, Hürthle cell carcinoma, FTC)

Patients are considered at high risk if any of the following is present:

  • Macroscopic tumor invasion
  • Incomplete tumor resection with gross residual disease
  • Distant metastases

The ATA guidelines define response to initial therapy (6–24 months after radioactive iodine ablation) as excellent if all the following are present:

  • Suppressed and stimulated Tg < 1 ng/mL
  • No evidence of disease on neck ultrasound (US)
  • Negative cross-sectional and/or nuclear medicine imaging (if performed)

Response is defined as acceptable if any of the following are present:

  • Suppressed Tg < 1 ng/mL and stimulated Tg ≥ 1 and < 10 ng/mL
  • Neck US with nonspecific changes or stable sub-centimeter lymph nodes
  • Cross-sectional and/or nuclear medicine imaging with nonspecific changes, although not completely normal

Response is defined as incomplete if any of the following are present:

  • Suppressed Tg ≥ 1 ng/mL or stimulated Tg ≥ 10 ng/mL
  • Rising Tg values
  • Persistent or newly identified disease on cross-sectional and/or nuclear medicine imaging

A comparison study in 98 patients with FTC concluded that the ATA staging system predicts recurrence rate and survival better than TNM staging. Hazard ratios were 4.67 with ATA staging versus 1.26 for TNM staging. [23]


Did this answer your question?
Additional feedback? (Optional)
Thank you for your feedback!