Evolution of benign thyroid nodules under levothyroxine non-suppressive therapy

Area of Science:

• Endocrinology
• Thyroidology
• Ultrasound Imaging

Background:

• Benign nodular goiter treatment efficacy is debated, with limited long-term follow-up data.
• Non-suppressive levothyroxine (L-T4) therapy shows potential for reducing thyroid nodule volume.

Purpose of the Study:

• To evaluate the long-term evolution of thyroid nodules under non-suppressive L-T4 treatment versus no treatment.
• To compare nodule growth patterns in treated versus untreated benign nodular goiter patients.

Main Methods:

• Longitudinal study (1-9 years) of 356 female patients (age 19-45).
• Two groups: 201 untreated (Group 0) and 165 treated with non-suppressive L-T4 (Group L-T4).
• Thyroid nodule volume measured via ultrasonography.

Main Results:

• Nodule volume increase was inversely correlated with initial nodule size.
• Final nodule volume was slightly higher in untreated subjects (5.37 mL) compared to L-T4 treated subjects (4.39 mL).
• Mean annual nodule growth rate slowed over time in both groups and was significantly lower in the L-T4 group.

Conclusions:

• Thyroid nodule growth naturally slows with time and is inversely related to initial size.
• Chronic, non-TSH-suppressive L-T4 treatment effectively reduces the growth rate of benign thyroid nodules.