Iodized salt improves the effectiveness of L-thyroxine therapy after surgery for nontoxic goitre: a prospective and randomized study.
ABSTRACT To investigate whether the addition of iodized salt to daily diet in thyroidectomized patients for nontoxic goitre could influence the effectiveness of nonsuppressive L-thyroxine (L-T4) therapy on thyroid remnant size, during 12 months' follow-up after thyroid surgery.
A consecutive series of selected 139 patients (26 males, 113 females; median age 45 years, range 30-69 years) living in a moderate iodine-deficient area, and undergoing thyroid surgery for nontoxic multinodular goitre, was enrolled. Patients were assigned randomly to two different therapeutic regimens: 70 patients received L-T4 therapy alone (Gr. L-T4), while the remaining 69 patients took iodized salt on a daily basis in addition to L-T4 treatment (Gr. L-T4 + I). In both groups, the initial L-T4 dose was 1.5 microg/kg/day, which, in our experience, has been shown to be intermediate between suppressive and replacement doses. To avoid the risks of mild thyrotoxicosis and to limit the excessive TSH stimulation of the thyroid remnant, the L-T4 dose was adjusted in those patients with serum TSH levels outside the lowest two-thirds of the normal range (0.3-2.5 mU/l). An ultrasound evaluation of thyroid remnant size was performed after thyroid surgery and 12 months later.
After surgery, the median thyroid remnant volume was 3.5 ml (range 0.4-13.9 ml) in Gr. L-T4 and 4.6 ml (range 0.5-12.7 ml) in Gr. L-T4 + I (P = 0.06). After 1 year of follow-up, the patients treated with L-T4 + I obtained a remnant volume reduction (-39.7%, range -87.0% to +91.2%) significantly (P = 0.006) greater than that observed in patients assuming L-T4 alone (-10.2%, range -89.4% to +85.0%). However, the percentage of patients showing an increase in remnant size in the months following surgery was higher in Gr. L-T4 than in Gr. L-T4 + I (22/60 vs. 9/66; P = 0.01). In Gr. L-T4 patients the thyroid remnant volume variation throughout 12 months of treatment was correlated significantly with the size of the thyroid remnant found at the first ultrasound evaluation (R(2) = 0.3; P < 0.001). No such correlation was found in Gr. L-T4 + I patients, for whom the therapy maintains a similar effectiveness in patients with either a large or a small postsurgery thyroid remnant. In patients treated with L-T4 alone, the remnant volume variation was correlated significantly with the median serum TSH values attained in the course of treatment (R2 = 0.4; P < 0.001). The highest reduction in remnant volume was observed only by lowering the serum TSH concentrations. In patients treated with L-T4 plus iodine, instead, the thyroid remnant volume reduction occurred independently of the plasma TSH levels attained in the course of treatment.
Our short-term prospective and randomized study leads us to conclude that, in patients living in a moderate iodine-deficient area and undergoing thyroid surgery for nontoxic goitre: (1) the iodine prophylaxis improves the effects of postsurgery nonsuppressive L-T4 therapy on thyroid remnant size. (2) In patients treated with L-T4 alone the therapeutic effectiveness decreases in the presence of a large postsurgery thyroid remnant. With the addition of iodine, the L-T4 maintains a similar efficacy in patients with either a large or a small remnant. (3) During treatment with L-T4 alone the highest therapeutic effectiveness is attained by lowering the plasma TSH concentration. With the addition of iodized salt to the daily diet the effects of L-T4 on remnant size are relevant independently of the TSH levels.
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ABSTRACT: The aim of the study was to identify the factors that are predictive of recurrence after thyroid lobectomy for unilateral non-toxic thyroid goiter in an endemic region through a multivariate analysis. Two hundred sixty-eight consecutive patients who underwent thyroid lobectomy and who were evaluated by the same endocrinologist were included. Univariate and multivariate analysis analyzed the relationship between sex, age, preoperative thyroid-stimulating hormone, duration of disease, duration of levothyroxine (LT4) preoperative therapy, cytologic results, histologic results, resected thyroid weight, numbers and diameters of thyroid nodules, morphologic alterations of the remnant lobe, follow-up length, postoperative LT4 therapy, ultrasonographic evidence of recurrence, and reoperation. The incidence of recurrence was 33.9% (91/268 patients) after a mean follow-up time of 79.9 months (range, 12-251 months), female sex ( P = .016), multiple nodules ( P = .017), and lack of postoperative LT4 therapy ( P = .0009) were predictive factors of recurrence. Reoperation was performed in 20 patients (7.4%); factors that were predictive of reoperation were the presence of multiple nodules ( P = .008), resected thyroid weight ( P = .00006), and lack of postoperative hormonal therapy ( P = .0005). Thyroid lobectomy for unilateral non-toxic goiter, when combined with suppressive or substitutive thyroxin therapy, resulted in a low rate of recurrence and reoperation in an endemic area.Surgery 01/2005; 136(6):1247-51. DOI:10.1016/j.surg.2004.06.054 · 3.11 Impact Factor
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ABSTRACT: Hauptindikation fr Schilddrsenoperationen ist die Entfernung von knotigem, potenziell malignem oder hyperfunktionellem Schilddrsengewebe. Postoperativ ist je nach Restfunktion eine L-Thyroxinsubstitution erforderlich. Gleichzeitig ist bei multinodser Struma zur Rezidivprophylaxe eine Jodidsupplementation indiziert. Bei Patienten mit differenziertem SD-Karzinom schlieen sich im Regelfall eine Radioiodbehandlung und risikoadaptierte Nachsorge an. Trotz unbefriedigender Datenlage ist davon auszugehen, dass Patienten mit niedrigem Rezidivrisiko von einer kompletten Thyreoablation und lebenslangen Thyreosuppression prognostisch nicht profitieren. Werden die Nebenschilddrsen in ihrer Funktion beeintrchtigt oder bei Hyperparathyreoidismus gezielt entfernt, kann sich eine behandlungsbedrftige Hypokalzmie entwickeln. Bei unzureichender Effektivitt einer oralen Kalziumsubstitution mssen additiv Vitamin D-Derivate eingesetzt werden, die aufgrund ihrer geringen therapeutischen Breite regelmige Laborkontrollen erfordern.The main indication for surgery of the thyroid gland is the resection of nodular, suspicious or hyperfunctioning tissue. Following thyroidectomy, L-thyroxine therapy is initiated adjusted to the remnant thyroid function. To prevent recurrence of a multinodular goiter, supplementation with iodine is strongly recommended. The management of patients with differentiated thyroid cancer depends on risk stratification. Although large prospective studies are missing, low-risk patients probably do not benefit from total thyroid ablation and lifelong thyroxine suppression therapy. As a result of impaired parathyroid function or resection of the parathyroid glands for hyperparathyroidism, acute or chronic hypocalcaemia can develop. If treatment with oral calcium is insufficient, the addition of a vitamin D analogue is necessary. This requires close monitoring to avoid renal or other hypercalcaemic complications.Der Internist 05/2007; 48(6):569-577. DOI:10.1007/s00108-007-1834-9 · 0.27 Impact Factor
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ABSTRACT: The main indication for surgery of the thyroid gland is the resection of nodular, suspicious or hyperfunctioning tissue. Following thyroidectomy, L-thyroxine therapy is initiated adjusted to the remnant thyroid function. To prevent recurrence of a multinodular goiter, supplementation with iodine is strongly recommended. The management of patients with differentiated thyroid cancer depends on risk stratification. Although large prospective studies are missing, low-risk patients probably do not benefit from total thyroid ablation and lifelong thyroxine suppression therapy. As a result of impaired parathyroid function or resection of the parathyroid glands for hyperparathyroidism, acute or chronic hypocalcaemia can develop. If treatment with oral calcium is insufficient, the addition of a vitamin D analogue is necessary. This requires close monitoring to avoid renal or other hypercalcaemic complications.Der Internist 07/2007; 48(6):569-77. · 0.27 Impact Factor