Life after thyroid cancer: the role of thyroglobulin and thyroglobulin antibodies for postoperative follow-up

ABSTRACT

Introduction

Differentiated thyroid carcinomas (DTCs) are treated with (near-)total thyroidectomy and radioiodine therapy. Recently, the use of highly sensitive thyroglobulin (hsTg) assays has simplified DTC follow-up and improved patients’ quality of life. More limited approaches are currently applied in low-risk patients requiring interpretations of Tg results in different clinical scenarios. Finally, Tg assays are hampered by interference from thyroglobulin autoantibodies (TgAb).

Areas covered

The role of Tg measurement in DTC patients treated with complete thyroid ablation, thyroidectomy alone, or lobectomy is summarized. The management of patients carrying positive TgAb is also addressed.

Expert opinion

Patients with undetectable hsTg after total thyroid ablation are safely managed by periodic hsTg measurement, combined with selective use of imaging procedures in few cases. Serum hsTg trend remains informative in patients treated without radioiodine ablation. However, reliable reference values are urgently needed in this setting. The role of hsTg is debated in patients who have undergone lobectomy due to the amount of Tg released by a functioning thyroid lobe. The evaluation of TgAb trend over time (i.e. surrogate tumor marker) is recommended in patients with positive TgAb and potentially interfering Tg results.

KEYWORDS:

• Thyroid cancer
• thyroglobulin
• follow-up
• ultrasound
• radioiodine

Funding

This paper was not funded.

Article highlights

• Currently available high-sensitive Tg assays obviate the need for TSH-stimulated Tg testing when monitoring most patients with DTC after primary treatment.

• In TgAb-negative patients, the non-stimulated hsTg trend provides highly relevant prognostic information.

• In TgAb-positive patients, interferences preclude reliable Tg measurements and the kinetics of TgAb levels (measured with the same method over time) may serve as a useful (surrogate) tumor marker.

• Future improvements in mass spectrometry Tg assays are expected in the future and may solve the problem of TgAb interferences.

• Serum Tg measurement may be employed in patients treated with thyroidectomy without radioiodine, as decreasing Tg levels are reassuring. Accurate data are urgently required, however, to better define the diagnostic performance, interpretation criteria, and pitfalls of both Tg and TgAb in these patients.

• The role of serum Tg measurement is limited in patients treated with lobectomy alone.

Declaration of interest

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

Reviewer disclosures

Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.