Levothyroxine suppressive therapy for solitary thyroid nodule

Abstract

In order to evaluate the efficacy of a TSH suppressive dose of levothyroxine to reduce the volume of a single thyroid nodule we studied 55 euthyroid patient: 45 (group A) were suppressed with LT4 (mean 1.7 +/- 0.9 micrograms/Kg/day) for 21.3 +/- 5.3 months, and 10 patients (group B) served as controls. All the nodules were "cold" at scintiscanning, solid at ultrasonography and benign by fine-needle aspiration cytology. As responders were assumed the nodules shrinked at the end of treatment of 50% in volume. Thyroid function values (TSH, T4, FT4, T3, FT3, thyroid peroxidase and thyroglobulin antibodies), clinical and ultrasonographic findings were evaluated initially and at the end of the study. A significant nodular volume decrease occurred in 8 treated patients (17.8%) while 37 (82.2%) amongst the group suppressed and all controls showed no change (A vs B = NS). In two untreated patients new nodules were noted; no new nodules were discovered in the treated group (A vs B p < 005). No side effects occurred in any treated patient, even if at the end of treatment a significant T4 and FT4 (p < 0.01) increase was observed. No one onset parameter can predict the response to the therapy. These results suggest that only a small group of patients affected by a single thyroid nodule seems to respond to a TSH suppressive therapy.

Effects of Thyroid-Stimulating Hormone Suppression with Levothyroxine in Reducing the Volume of Solitary Thyroid Nodules and Improving Extranodular Nonpalpable Changes: A Randomized, Double-Blind, Placebo-Controlled Trial by the French Thyroid Research Group

“…Heart rate, blood pressure, and body weight were not significantly affected by l-T 4 compared with placebo in our study, despite daily doses sufficient to suppress TSH. No other similar clinical trial has consistently demonstrated a higher risk for l-T 4 than placebo or no treatment (12,13). An interesting way of improving the risk-benefit ratio of l-T 4 would be to identify a subgroup of patients whose nodules will presumably respond to this drug.…”

“…The purpose of l-T 4 administration was originally to reduce the growthpromoting effect of TSH (8 -10). However, during the last 15 yr, several authors have undermined this concept by failing to prove the efficacy of l-T 4 (11)(12)(13)(14). Others believe that nodules should be left to regress spontaneously (15)(16)(17).…”

“…Concern was also expressed about the risk-benefit ratio of l-T 4 administration (17,18). Nevertheless, general clinical experience, controlled studies (12,19), as well as a recent metaanalysis (20) and a study using the so-called quantitative research synthesis (21) indicate that at least some nodules shrink under l-T 4 . Furthermore, negative studies may have been hampered by imprecise definition of the nodules, insufficient l-T 4 dosage or duration of treatment, or insufficiently restrictive inclusion criteria.…”

Thyroxine Suppression Therapy For Benign, Non-Functioning Solitary Thyroid Nodules: A Quality-Effects Meta-Analysis

“…Of 19 studies identified, data from 11 were included 3,[7][8][9][10][11][12][13][14][15][16] and eight studies were excluded. Of these eight, we sent a request for data to the authors of three studies [17][18][19] as the data in the papers were insufficient to decide how many people failed in either one or both treatment groups.…”

Reduction of Thyroid Nodule Volume by Levothyroxine and Iodine Alone and in Combination: A Randomized, Placebo-Controlled Trial

“…In addition, half of the previous studies on the efficacy of T 4 treatment have used a fully TSH-suppressive regimen (TSH < 0.1) with high T 4 doses (8–11, 13, 14), which is no longer acceptable because of frequent side effects. Other studies (12, 15–18) aimed to achieve a partially suppressed TSH value (upper limit 0.4).…”