Factors Affecting Suppression of Endogenous Thyrotropin Secretion by Thyroxine Treatment: Retrospective Analysis in Athyreotic and Goitrous Patients*

Bartalena, Luigi; Martino, Enio; Pacchiarotti, Alessandro; Grasso, Lucia; Aghini-Lombardi, F.; Buratti, Laura; Bambini, G.; Breccia, M.; Pinchera, Aldo

doi:10.1210/jcem-64-4-849

Cited by 63 publications

(17 citation statements)

References 27 publications

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“…Meanwhile, patients with moderately suppressed TSH levels postoperatively had higher serum FT 4 levels and unchanged serum FT 3 levels compared with their native levels, findings that are in agreement with those of Silva & Larsen (13). Indeed, most physicians encounter patients on TSH-suppressive doses of L-T 4 therapy who have serum T 4 levels higher than the normal upper limit and normal T 3 levels (2,3,5). In general, most clinicians believe that a low-serum TSH level indicates subclinical thyrotoxicosis and is a risk factor for cardiac dysfunction or osteoporosis (17).…”

Section: Discussionsupporting

confidence: 78%

“…In normal subjects, T 4 is secreted by the thyroid (about 100%) and T 3 as the active form is produced by the thyroid gland (about 20%) or is derived from the conversion of T 4 to T 3 in extra-thyroidal peripheral tissues (80%) (1). T 4 therapy using synthetic levothyroxine (L-T 4 ) is the standard of care for patients who had undergone total thyroidectomy (2,3). Thyroidal production of T 3 is absent in postoperative athyreotic patients.…”

Section: Introductionmentioning

confidence: 99%

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TSH-suppressive doses of levothyroxine are required to achieve preoperative native serum triiodothyronine levels in patients who have undergone total thyroidectomy

Miyauchi

Morita

et al. 2012

European Journal of Endocrinology

110

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Objective: Thyroidal production of triiodothyronine (T 3 ) is absent in patients who have undergone total thyroidectomy. Therefore, relative T 3 deficiency may occur during postoperative levothyroxine (L-T 4 ) therapy. The objective of this study was to evaluate how the individual serum T 3 level changes between preoperative native thyroid function and postoperative L-T 4 therapy. Methods: We retrospectively studied 135 consecutive patients with papillary thyroid carcinoma, who underwent total thyroidectomy. Serum free T 4 (FT 4 ), free T 3 (FT 3 ), and TSH levels measured preoperatively were compared with those levels measured on postoperative L-T 4 therapy. Results: Serum TSH levels during postoperative L-T 4 therapy were significantly decreased compared with native TSH levels (P!0.001). Serum FT 4 levels were significantly increased (P!0.001). Serum FT 3 levels were significantly decreased (PZ0.029). We divided the patients into four groups according to postoperative serum TSH levels: strongly suppressed (less than one-tenth of the lower limit); moderately suppressed (between one-tenth of the lower limit and the lower limit); normal limit; and more than upper limit. Patients with strongly suppressed TSH levels had serum FT 3 levels significantly higher than the native levels (P!0.001). Patients with moderately suppressed TSH levels had serum FT 3 levels equivalent to the native levels (PZ0.51), and patients with normal TSH levels had significantly lower serum FT 3 levels (P!0.001). Conclusions: Serum FT 3 levels during postoperative L-T 4 therapy were equivalent to the preoperative levels in patients with moderately suppressed TSH levels. Our study indicated that a moderately TSH-suppressive dose of L-T 4 is required to achieve the preoperative native serum T 3 levels in postoperative L-T 4 therapy.

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Section: Discussionsupporting

confidence: 78%

Section: Introductionmentioning

confidence: 99%

TSH-suppressive doses of levothyroxine are required to achieve preoperative native serum triiodothyronine levels in patients who have undergone total thyroidectomy

Miyauchi

Morita

et al. 2012

European Journal of Endocrinology

110

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“…(D) The initial LT4 daily dose is around 2 mg/kg body weight in young adults, being higher in children and lower in elderly patients (18). LT4 should be taken in a single dose in the morning, on an empty stomach, 20 -30 min before breakfast.…”

Section: Commentsmentioning

confidence: 99%

Follow-up and management of differentiated thyroid carcinoma: a European perspective in clinical practice

Schlumberger

Pacini

Wiersinga

et al. 2004

European Journal of Endocrinology

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As differentiated (follicular and papillary) thyroid cancer (DTC) may recur years after initial treatment, follow-up of patients with DTC is long term. However, this population has changed, with more individuals being discovered at an earlier stage of disease, so that previous follow-up protocols based mostly on data from high-risk patients no longer apply. We have proposed, in a previous issue of this Journal, an improved protocol for the follow-up of low-risk patients with DTC based on the findings of recent studies. We report here the case of a paradigmatic patient with papillary thyroid carcinoma, with the goal of illustrating the benefits of applying this algorithm in routine clinical practice. We also offer expanded and additional comments on various issues in the management of DTC.

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“…However, given that the incidence of thyroid cancer is consistently higher in women than in men 3,4 and the finding that estrogen receptors are present in papillary and follicular thyroid carcinomas (the 2 major histologic subtypes of thyroid cancer), 4 it has been hypothesized that hormonal factors may be involved in the etiology of thyroid cancer. Furthermore, there is experimental evidence that elevated thyroid-stimulating hormone (TSH) levels may play a role in the development of thyroid carcinomas [5][6][7][8][9] and epidemiologic evidence that smoking [10][11][12][13] and alcohol consumption 14 may be inversely associated with TSH production, which suggests that they might be inversely associated with thyroid cancer risk.…”

mentioning

confidence: 99%

Risk factors for thyroid cancer: A prospective cohort study

Silvera¹,

Miller²,

Rohan³

2005

Intl Journal of Cancer

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Given the higher incidence rate of thyroid cancer among women compared to men and evidence that smoking and alcohol consumption may be inversely related to thyroid cancer risk, we examined thyroid cancer risk in association with menstrual, reproductive and hormonal factors, and cigarette and alcohol consumption, in a prospective cohort study of 89,835 Canadian women aged 40-59 at recruitment who were enrolled in the National Breast Screening Study (NBSS). Linkages to national cancer and mortality databases yielded data on cancer incidence and deaths from all causes, respectively, with follow-up ending between 1998 and 2000. Cox proportional hazards models (using age as the time scale) were used to estimate hazard ratios and 95% confidence intervals for the association between each of the potential risk factors and risk of thyroid cancer overall and by the main histologic subtypes. During a mean of 15.9 years of followup, we observed 169 incident thyroid cancer cases. There was no evidence of altered overall thyroid cancer risk with any of the menstrual, reproductive, or hormonal factors. There was evidence of a decreased risk of papillary thyroid cancer among women with 5 or more live births (vs. nulliparous). Age at which smoking commenced, duration of smoking, number of cigarettes smoked per day, pack-years of smoking and alcohol consumption were not associated with altered thyroid cancer risk. The present study provides little support for associations with hormonal factors, smoking, or alcohol consumption, but there is a need for additional prospective data. ' 2005 Wiley-Liss, Inc.Key words: thyroid neoplasms; prospective cohort; reproductive and hormonal risk factors; smoking history; alcohol consumption Thyroid carcinomas are generally rare, with an annual incidence rate of approximately 5.7 per 100,000 in the United States.1 Other than ionizing radiation, the only definitively established risk factor for this disease, 2 little is known about the etiology of thyroid cancer. However, given that the incidence of thyroid cancer is consistently higher in women than in men 3,4 and the finding that estrogen receptors are present in papillary and follicular thyroid carcinomas (the 2 major histologic subtypes of thyroid cancer), 4 it has been hypothesized that hormonal factors may be involved in the etiology of thyroid cancer. Furthermore, there is experimental evidence that elevated thyroid-stimulating hormone (TSH) levels may play a role in the development of thyroid carcinomas 5-9 and epidemiologic evidence that smoking 10-13 and alcohol consumption 14 may be inversely associated with TSH production, which suggests that they might be inversely associated with thyroid cancer risk.The epidemiologic literature regarding the risk of thyroid cancer in association with menstrual and reproductive factors and use of exogenous hormones is based primarily on the results of casecontrol studies, and findings, with respect to the roles of parity, age at first birth, age at menarche, oral contraceptive use, use of hormone re...

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Factors Affecting Suppression of Endogenous Thyrotropin Secretion by Thyroxine Treatment: Retrospective Analysis in Athyreotic and Goitrous Patients*

Cited by 63 publications

References 27 publications

TSH-suppressive doses of levothyroxine are required to achieve preoperative native serum triiodothyronine levels in patients who have undergone total thyroidectomy

TSH-suppressive doses of levothyroxine are required to achieve preoperative native serum triiodothyronine levels in patients who have undergone total thyroidectomy

Follow-up and management of differentiated thyroid carcinoma: a European perspective in clinical practice

Risk factors for thyroid cancer: A prospective cohort study

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