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. · 3.37 Impact Factor
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ABSTRACT: The aim of this study was to compare the prevalence of recurrent nodular goiter in the contralateral thyroid lobe among patients after unilateral thyroid lobectomy for unilateral multinodular goiter (MNG) receiving versus not receiving postoperative prophylactic levothyroxine (LT4) treatment. From January 2000 through December 2003, 150 consenting patients underwent a unilateral thyroid lobectomy for unilateral MNG at our institution. They were randomized to two groups with 75 patients in each group. Patients in group A received prophylactic LT4 treatment postoperatively (dose range 75-125 microg/day to maintain thyroid-stimulating hormone values below 1.0 mU/L), whereas patients in group B received no postoperative LT4 treatment. All the patients underwent ultrasonographic, cytologic, and biochemical follow-up for at least 60 months postoperatively. The primary outcome was the prevalence of recurrent goiter in the contralateral thyroid lobe. The secondary outcome was the reoperation rate for recurrent goiter. The outcomes were stratified according to individual iodine metabolism status assessed by urinary iodine excretion. During the 5-year follow-up, among patients receiving vs. not receiving LT4, recurrent goiter within the contralateral thyroid lobe was found in 1.4% vs. 16.7% of patients, respectively (p = 0.001). Moreover, 1.4% vs. 8.3%, respectively, of patients receiving vs. not receiving LT4 required contralateral thyroid lobe surgery (p = 0.05). LT4 decreased the recurrence rate among iodine-deficient patients (3.4% vs. 36%, respectively; p = 0.002) but not among iodine-sufficient patients (0% vs. 6.4%, respectively; p = 0.09). Prophylactic LT4 treatment significantly decreased the recurrence rate of nodular goiter in the contralateral thyroid lobe and the need for completion thyroidectomy, mostly among patients with iodine deficiency.World Journal of Surgery 06/2010; 34(6):1232-8. · 2.23 Impact Factor
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ABSTRACT: The extent of thyroid resection in multinodular nontoxic goiter (MNG) is controversial. The aim of the present study was to evaluate results of various thyroid resection modes, with special emphasis put on the recurrence rate and morbidity rate, in a 5-year follow-up. From 01/2000 through 12/2003, 600 consenting patients with MNG qualified for thyroidectomy at our institution were randomized to three groups equal in size, n = 200 in each. Patients in group A underwent total thyroidectomy (TT); patients in group B underwent Dunhill operation (DO), whereas patients in group C underwent bilateral subtotal thyroidectomy (BST). All patients were subjected to ultrasonographic, cytological, and biochemical follow-up at least for 60 months postoperatively. The primary outcome measure was prevalence of recurrent goiter and need for redo surgery. The secondary outcome measure was the postoperative morbidity rate (hypoparathyroidism and recurrent laryngeal nerve injury). Recurrent goiter was found in 0.52% TT versus 4.71% DO versus 11.58% BST (p = 0.01 for TT versus DO, p = 0.02 for DO versus BST, p < 0.001 for TT versus BST), and completion thyroidectomy was necessary in 0.52% TT versus 1.57% DO versus 3.68% BST (p = 0.03 for TT versus BST). Transient postoperative hypoparathyroidism was present in 10.99% versus 4.23% versus 2.1% (p = 0.007 for TT versus DO, p < 0.001 for TT versus BST), whereas the recurrent laryngeal nerve injury rate was 5.49% and 1.05% TT versus 4.23% and 0.79% DO versus 2.1% and 0.53% BST (transient and permanent, respectively; p = 0.007 for transient events TT versus BST). Total thyroidectomy can be regarded as the procedure of choice for patients with MNG. It is associated with a significantly lower incidence of goiter recurrence and less frequent need for completion thyroidectomy than other more limited thyroid resections. However, TT involves a significantly higher risk of postoperative transient but not permanent hypoparathyroidism and recurrent laryngeal nerve paresis.World Journal of Surgery 02/2010; 34(6):1203-13. · 2.23 Impact Factor