Differentiated Thyroid Cancer with Biochemical Incomplete Response: Clinico-Pathological Characteristics and Long...

Area of Science:

• Endocrinology
• Oncology
• Thyroid Cancer Research

Background:

• Differentiated thyroid cancer (DTC) patients with biochemical incomplete response (BIR) often have favorable outcomes.
• However, a subset of BIR patients (8-17%) may progress to structural disease.

Purpose of the Study:

• To identify predictors of long-term outcomes in patients with differentiated thyroid cancer and biochemical incomplete response.
• To evaluate the utility of established staging systems in predicting disease progression in BIR patients.

Main Methods:

• Retrospective review of 1049 patients with DTC treated with total thyroidectomy (1962-2019).
• BIR defined by specific thyroglobulin (Tg) levels or anti-Tg antibodies without structural disease at 12-24 months post-treatment.
• Analysis of American Thyroid Association (ATA) Initial Risk Stratification and AJCC/TNM (8th ed.) staging for prediction of structural disease progression.

Main Results:

• 83 patients (7.9%) met the BIR criteria.
• Over a mean follow-up of 12 years, 41% of BIR patients progressed to structural disease.
• Disease-related death occurred in 3.6% of BIR patients.
• ATA and AJCC/TNM staging at diagnosis predicted structural disease progression, independent of postoperative Tg levels.

Conclusions:

• While 41% of BIR patients may develop structural disease, the progression is often indolent.
• Risk stratification systems at diagnosis are valuable for predicting structural disease shifts in BIR patients.
• Dynamic reclassification based on response to therapy can improve long-term management of BIR patients.