A new study challenges the 2025 ATA guideline's thyroglobulin cutoff of 2.5 ng/mL as a standalone marker of remission in higher-risk thyroid cancer patients. Researchers found that about 3.5% of low-intermediate- and intermediate-high-risk patients developed cancer recurrence despite thyroglobulin levels staying below the cutoff. Clinicians are urged to pair thyroglobulin monitoring with neck ultrasounds for more reliable follow-up.
The 2025 American Thyroid Association (ATA) guidelines introduced a new thyroglobulin cutoff of 2.5 ng/mL to define "excellent response" to treatment in differentiated thyroid cancer patients who underwent total thyroidectomy without radioactive iodine. While this update reclassified more patients as doing well — a welcome change for many — a new retrospective study from the University of Washington suggests the cutoff may fall short for higher-risk patients.
Researchers analyzed 205 adults with differentiated thyroid cancer and found that three patients classified as having an "excellent response" under the new 2.5 ng/mL threshold still experienced cancer recurrence. All three were in the low-intermediate- or intermediate-high-risk groups. Notably, when the older 0.2 ng/mL cutoff was applied, all recurrence cases would have been flagged as indeterminate or incomplete responses.
Key Takeaways:
Why it matters: Mislabeling a higher-risk thyroid cancer patient as "in remission" could delay critical follow-up. Experts recommend pairing thyroglobulin testing with neck ultrasounds for 5–8 years post-surgery in intermediate- and higher-risk patients.
