Thyrotropin Level and Thyroid Volume for Prediction of Hypothyroidism Following Hemithyroidectomy in an Asian Patient Cohort

Prevalence of and Predictive Factors for Hypothyroidism Following Hemithyroidectomy

PURPOSE

Hemithyroidectomy is an appropriate procedure that is recommended for a number of thyroid conditions to preserve the functional contralateral thyroid lobe, but patients who underwent a hemithyroidectomy still run the risk of developing hypothyroidism. This study aimed to determine the incidence of hypothyroidism following a hemithyroidectomy as well as predictive risk factors.

METHODS

A retrospective analysis was carried out on all patients who underwent hemithyroidectomy between 2016 and 2022. Age, gender, preoperative and postoperative thyroid stimulating hormone (TSH) and free thyroxin (FT4), side, and volume of the remaining lobe, as well as the histologic diagnosis, were all examined in the patients. To identify the predictors of hypothyroidism, statistical analyses, both univariate and multivariate, were conducted.

RESULTS

Out of 224 patients, 18.25% had hypothyroidism following surgery. This complication appeared within the first year in 88% of the cases. Patients with thyroiditis (P = .036), preoperative TSH levels greater than 1.72 mIU/L (P < .001), right side hemithyroidectomy (P = .017), and residual lobe volume less than 3.57 cm (P < .001) had a significantly higher risk of developing hypothyroidism.

CONCLUSION

After hemithyroidectomy, hypothyroidism is a major complication that should be carefully evaluated preoperatively based on risk factors of hypothyroidism. Furthermore, our results confirm the need for routine serum TSH monitoring for a minimum of 1 year following hemithyroidectomy.

Hypothyroidism after hemithyroidectomy: a systematic review and meta-analysis

BACKGROUND

The incidence of hypothyroidism following hemithyroidectomy and risk factors associated with its occurrence are not completely understood. This systematic review investigated the incidence and risk factors for hypothyroidism, thyroxine supplementation following hemithyroidectomy as well as the course of post-operative hypothyroidism, including the time to hypothyroidism and incidence of transient hypothyroidism.

METHODS

Searches were conducted in MEDLINE, EMBASE, Scopus, and Cochrane library for studies reporting the incidence of hypothyroidism or thyroxine supplementation following hemithyroidectomy.

RESULTS

Sixty-six studies were eligible for inclusion: 36 reported risk factors, and 27 reported post-operative course of hypothyroidism. Median follow-up was 25.2 months. The pooled incidence of hypothyroidism was 29% (95% CI, 25-34%; P<0.001). Transient hypothyroidism occurred in 34% of patients (95% CI, 21-47%; P<0.001). The pooled incidence of thyroxine supplementation was 23% (95% CI, 19-27%; P<0.001), overt hypothyroidism 4% (95% CI, 2-6%, P<0.001). Risk factors for development of hypothyroidism included pre-operative thyroid stimulating hormone (TSH) (WMD, 0.87; 95% CI, 0.75-0.98; P<0.001), TSH ≥ 2 mIU/L (RR, 2.87; 95% CI, 2.43-3.40; P<0.001), female sex (RR, 1.19; 95% CI, 1.08-1.32; P=0.007), age (WMD, 2.29; 95% CI, 1.20-3.38; P<0.001), right sided hemithyroidectomy (RR, 1.35; 95% CI, 1.10-1.65, P=0.003), the presence of autoantibodies anti-TPO (RR, 1.92; 95% CI, 1.49-2.48; P<0.001), anti-Tg (RR, 1.53; 95% CI, 1.40-1.88; P<0.001), and Hashimoto's thyroiditis (RR, 2.05; 95% CI, 1.57-2.68; P=0.001).

CONCLUSION

A significant number of patients will develop hypothyroidism or require thyroxine following hemithyroidectomy. An awareness of patient risk factors and postoperative thyroid function course will assist in counselling patients on their risk profile and guiding management.

Posthemithyroidectomy Hypothyroidism: Updated Meta-Analysis of Risk Factors and Rates of Remission

INTRODUCTION

The aim of this study was to determine the incidence and risk factors for hypothyroidism, both clinical and subclinical, following hemithyroidectomy in preoperatively euthyroid patients, as well as hypothyroidism remission and its time of remission.

MATERIALS AND METHODS

A search was performed in Medline (via PubMed), Web of Science, and the Cochrane Library using the keywords "hemithyroidectomy + postoperative + hypothyroidism" and "hemithyroidectomy + hormone supplementation".

RESULTS

Fifty-four studies with a total of 9,999 patients were included. After a mean follow-up interval of 48.2 mo, the pooled hypothyroidism rate was 29%. The subclinical hypothyroidism rate was 79% of patients with hypothyroidism (18 studies). Moreover, a meta-analysis of 12 studies indicated a pooled hypothyroidism remission rate after hemithyroidectomy of 42% (95% CI: 24%-60%). Older patient age (MD = -2.54, 95% CI = -3.99, -1.10, P = 0.0006), female gender (OR = 0.69, 95% CI = 0.58, 0.82, P < 0.0001), higher preoperative thyroid-stimulating hormone levels (MD = -0,81, 95% CI = -0.96, -0.66, P < 0.00001), pathological preoperative anti-thyroid peroxidase antibodies (OR = 0.37, 95% CI = 0.24, 0.57, P < 0.00001) and anti-thyroglobulin antibodies (OR = 0.52, 95% CI = 0.36, 0.75, P = 00,005), and right-sided hemithyroidectomy (OR = 0.54, 95% CI = 0.43, 0.68, P < 0.00001) were associated with postoperative hypothyroidism development. In metaregression analysis, Asia presented a significantly higher hypothyroidism rate after hemithyroidectomy (34.6%, 95% CI = 29.3%-9.9%), compared to Europe (22.9%, 95% CI = 16.2%-29.5%, P = 0.037) and Canada (1.8%, 95% CI = -22.6%-26.2%, P = 0.013).

CONCLUSIONS

Hypothyroidism is a frequent and significant postoperative sequela of hemithyroidectomy, necessitating individualization of treatment strategy based on the underlying disease as well as the estimated risk of hypothyroidism and its risk factors.

Risk factors for hypothyroidism following hemithyroidectomy

OBJECTIVE

Hypothyroidism is the most common complication of hemithyroidectomy for thyroid nodules. This retrospective cohort study investigated the prognostic factors for hypothyroidism following hemithyroidectomy.

METHODS

We included patients who underwent hemithyroidectomy between 2016 and 2017, excluding those with history of preoperative hypothyroidism or malignancy on histopathological examination. The primary endpoint was development of hypothyroidism during follow-up (TSH≥2 above normal).

RESULTS

Twenty-six of the 128 included patients (20%) developed postoperative hypothyroidism. The following independent prognostic factors were found: preoperative TSH level>1.5 mIU/L (OR 2.11; P=0.013), and remaining thyroid volume adjusted for body surface area<4.0mL/m2 (OR 1.77; P=0.015). Twenty-one patients (81%) had first TSH values above the upper limit of normal. Postoperatively, first TSH level correlated significantly with the preoperative value (R=0.5779, P<0.001). Levothyroxine was prescribed to 16% of patients, with a mean dose of 0.92μg/kg/day.

CONCLUSION

Patients with TSH>1.5 mIU/or remaining thyroid volume adjusted for body surface area<4.0mL/m2 should have intensified clinical and biological follow-up in the first year after surgery.

Time to Hypothyroidism Following Hemithyroidectomy

Background The time to hypothyroidism post hemithyroidectomy is variable. There are multiple risk factors for developing hypothyroidism. The aim of this study was to identify the time of hypothyroidism and other predictors of hypothyroidism in euthyroid patients following hemithyroidectomy. Methods This was a retrospective study. Of 170 euthyroid patients who underwent hemithyroidectomy for benign disease between 2006 - 2014, age, gender, pre-operative thyroid function tests, body mass index (BMI), and other co-morbidities were examined to determine predictors of early (<3 months) or late (>3 months) hypothyroidism. A high normal preoperative thyroid stimulating hormone (HN-TSH) was defined as ≥2.01 uIU/ml, and a low normal TSH (LN-TSH) was defined as <2.01 uIU/ml. Results A total of 63 of the 170 patients (37%) became hypothyroid. At 3 months, 21.5% of patients were hypothyroid. At 6 months after operation, an additional 5% had become hypothyroid, and after 1 year, 8% more were hypothyroid. The only independent predictor of hypothyroidism was preoperative HN-TSH (≥2.01) (p<0.001) on multivariate analysis. Conclusion In addition to known predictors of hypothyroidism following hemithyroidectomy for benign disease, such as the size of the thyroid remnant, a history of neck irradiation, and coexisting thyroid autoimmune disease, a BMI ≥35 kg/m², age ≥45, and preoperative HN-TSH are risk factors for postoperative hypothyroidism within 3 months of operation. Such patients should be closely monitored.

Risk factors for hypothyroidism and thyroid hormone replacement after hemithyroidectomy in papillary thyroid carcinoma

PURPOSE

Thyroid lobectomy is now preferred over total thyroidectomy to preserve thyroid function and reduce complications in patients with low-risk papillary thyroid carcinoma (PTC). One inevitable consequence of thyroidectomy includes hypothyroidism. This study aimed to evaluate the risk factors for hypothyroidism and thyroid hormone replacement after hemithyroidectomy in patients with PTC.

METHODS

We retrospectively studied 353 patients with PTC who underwent hemithyroidectomy with or without central neck dissection from January 2012 to January 2019. We excluded patients who had hypo- or hyperthyroidism preoperatively and those who underwent total or subtotal thyroidectomy. We analyzed various risk factors related to postoperative hypothyroidism and thyroid hormone supplementation.

RESULTS

Of the patients, 54.7% showed hypothyroidism after hemithyroidectomy (n=193 with n=157, subclinical hypothyroidism; n=36, overt hypothyroidism). Ninety-one percent of postoperative hypothyroidism cases developed within 7 months postoperatively. Eventually, 43.1% (n=152) of patients received levothyroxine after hemithyroidectomy. Preoperative high thyroid-stimulating hormone (TSH) level and low free thyroxine (fT4) level were significantly associated with postoperative hypothyroidism and the need for thyroid hormone supplementation postoperatively.

CONCLUSION

Preoperative TSH and fT4 levels are predictive risk factors of hypothyroidism and need for supplementation of levothyroxine after hemithyroidectomy in patients with PTC. Finally, approximately 43% of patients need levothyroxine supplementation after hemithyroidectomy, and individual preoperative counseling is necessary for these patients.

Comparison of the Incidence of Postoperative Hypothyroidism in Patients Undergoing Conventional Thyroid Lobectomy and Pyramid- and Isthmus-Preserving Lobectomy

Hypothyroidism is a recognized sequela of conventional thyroid lobectomy. However, there have been no studies on the incidence of hypothyroidism following the preservation of the isthmus and pyramid during lobectomy. Therefore, in the present study, we compared the incidence of hypothyroidism following conventional lobectomy and lobectomy during which the isthmus and pyramidal lobe were preserved. Data for a total of 65 patients collected between September 2018 and April 2019 were reviewed retrospectively. Circulating thyroid-stimulating hormone (TSH) concentration was measured before and after surgery in a group who underwent conventional thyroid lobectomy (n = 29) and in a group in which the isthmus and pyramid were preserved (n = 36). We found no significant difference in TSH concentration between the two groups before surgery, or 3 months or 1 year after surgery. Thus, there might be no difference in the incidence of postoperative hypothyroidism between patients who undergo conventional thyroid lobectomy and those in which the isthmus and pyramid are preserved.

Prevalence of and risk factors for hypothyroidism after hemithyroidectomy: a systematic review and meta-analysis

PURPOSE

This systematic review and meta-analysis evaluated the prevalence of and risk factors for hypothyroidism following hemithyroidectomy as new evidence obtained in recent years warranted an update of previous meta-analyses.

METHODS

The PubMed, Embase, and Cochrane Library databases were searched through November 1, 2019, for articles examining the hypothyroidism prevalence and risk factors after lobectomy. The prevalence rate, risk ratio (RR), weighted mean difference (WMD) and standardized mean difference (SMD) were assessed by conducting a meta-analysis of proportions, binary variables, and continuous variables, respectively, using random-effects models.

RESULTS

Fifty-one studies showed a pooled risk of 29.9% (95% confidence interval (CI), 24.6-35.2%) for hypothyroidism following hemithyroidectomy. Risk factors for the development of postoperative hypothyroidism included the female sex (RR, 1.169; 95% CI, 1.040-1.314; P = 0.009), a higher preoperative thyrotropin (TSH) level (RR, 2.955; 95% CI, 2.399-3.640; P = 0.000), a lower preoperative FT4 level (SMD, -0.818; 95% CI, -1.623--0.013; P = 0.047), concomitant lymphocyte infiltration (RR, 1.558; 95% CI, 1.203-2.018; P = 0.001), Hashimoto's thyroiditis (HT) (RR, 1.480; 95% CI, 1.192-1.838; P = 0.000), a lighter weight of the remaining gland (WMD, -2.740; 95% CI, -3.708--1.772; P = 0.000), and a right side lobectomy (RR, 1.404; 95% CI, 1.075-1.835; P = 0.013).

CONCLUSIONS

Hypothyroidism is a significant complication after lobectomy, and appropriate and personalized surgical strategies should be designed after a careful preoperative assessment based on the estimated risk of hypothyroidism and risk factors.

The Recovery of Thyroid Function in Low-Risk Papillary Thyroid Cancer After Lobectomy: A 3-Year Follow-Up Study

PURPOSE

Management strategies after lobectomy for low-risk papillary thyroid carcinoma (PTC) are controversial. This study aimed to identify the proportion of patients among low-risk PTC patients who do not require hormone replacement therapy and to evaluate the risk factors for postoperative hypothyroidism after lobectomy.

PATIENTS AND METHODS

The records of 190 PTC patients who underwent thyroid lobectomy from January 2017 to December 2018 were retrospectively reviewed. Clinicopathological characteristics and follow-up data were collected. Univariate and multivariate analyses were performed to identify the risk factors associated with postoperative hypothyroidism and the recovery of thyroid function.

RESULTS

In summary, 74.21% of patients (141/190) had normal thyroid function without levothyroxine supplementation, while 40.53% (77/190) developed temporary or permanent hypothyroidism. Multivariate analysis indicated that higher preoperative thyroid-stimulating hormone (TSH) levels (>2.62 mIU/L), Hashimoto's thyroiditis (HT), and right lobectomy were associated with hypothyroidism (all P<0.05). The Area Under Curve (AUC) by logistic analysis was 0.829. Twenty-eight (28/77, 36.4%) patients recovered to the euthyroid state in the first year after surgery, and this recovery was significantly associated with preoperative TSH level. Forty-nine (49/77, 63.6%) patients developed persistent hypothyroidism. The thyroid function of most patients (11/28, 39.3%) recovered in the third month after surgery.

CONCLUSION

Patients with a lower level of preoperative TSH, with left lobectomy and without Hashimoto's thyroiditis had a higher chance of normal thyroid function within the first year after lobectomy. The recovery of thyroid function was associated with the level of preoperative TSH.

Predictors of thyroxine replacement following hemithyroidectomy in a south east Asian cohort

BACKGROUND

Thyroxine replacement following a hemithyroidectomy is not commonly discussed during consent for the procedure as the risk of hypothyroidism is perceived to be low.

METHODS

Retrospective review of 901 patients who underwent hemithyroidectomy at a tertiary referral institution during the period January 2000 to December 2015. The main outcome studied was the overall incidence of hypothyroidism and the associated risk factors.

RESULTS

Hypothyroidism developed in 123 (13%) patients and 94 patients (10%) required hormone supplementation over a mean follow up of 21 months (range 1-168 months). Preoperative TSH of more than 2.5 was seen in 38 of 123 (31%) of patients. Presence of diffuse thyroiditis was the only independent risk factor on multivariate analysis (P = 0.002) found to be associated with the development of hypothyroidism.

CONCLUSION

After thyroid lobectomy, approximately one in 10 patients requiring thyroid hormone treatment for hypothyroidism. Presence of diffuse thyroiditis is a significant risk factor for hypothyroidism.

Effect of Thyroid Remnant Volume on the Risk of Hypothyroidism After Hemithyroidectomy: A Prospective Study

BACKGROUND

Hypothyroidism is a common sequel after a hemithyroidectomy. Although various risk factors leading to hypothyroidism have been reported, the effect of the contralateral lobe's volume has been understudied. This study aimed to examine the association between the preoperative contralateral lobe's volume and the risk of postoperative hypothyroidism.

METHODS

During a 2-year period, 150 eligible patients undergoing a hemithyroidectomy were evaluated. The volume of the contralateral nonexcised lobe was estimated preoperatively by independent assessors on ultrasonography using the following formula: width (in cm) × depth (in cm) × length (in cm) × (π/6), adjusted for the body surface area (BSA). Postoperative hypothyroidism was defined as serum thyroid-stimulating hormone (TSH) exceeding 4.78 mIU/L. Any significant characteristics in the univariate analysis were entered into the multivariate analysis to determine independent factors.

RESULTS

After a mean follow-up period of 53.5 ± 9.4 months, 44 patients (29.3 %) experienced postoperative hypothyroidism, and 10 of these patients required thyroxine replacement. Hypothyroidism was associated with a higher preoperative TSH level (p < 0.001), a smaller BSA-adjusted volume (p < 0.001), fewer ipsilateral nodules (p = 0.037), and the presence of thyroiditis (p = 0.050). After adjustment for thyroiditis, preoperative TSH (p < 0.001), number of ipsilateral nodules (p = 0.048), and BSA-adjusted volume (p < 0.001) were independent factors for hypothyroidism. Patients with a BSA-adjusted volume smaller than 3.2 ml had a threefold greater hypothyroidism risk than those with a BSA-adjusted volume of 3.2 ml or more (p < 0.001).

CONCLUSIONS

A significant inverse association between the preoperative contralateral lobe's volume and hypothyroidism risk was observed after hemithyroidectomy. Together with a higher preoperative TSH level and fewer ipsilateral nodules, a smaller BSA-adjusted volume measured by preoperative ultrasonography independently predicted hypothyroidism.

Efficacy of primary tumour volume as a predictor of survival compared with size alone in pancreatic ductal adenocarcinoma

Tumour size (TSize) predicts outcome in pancreatic ductal adenocarcinoma (PDAC), but little is known regarding three-dimensional tumour volume (TVol) associations. We hypothesised that TVol would more accurately predict outcome following pancreatoduodenectomy (PD) for PDAC. Clinicopathological and outcome data was reviewed for all PDs performed in the Royal North Shore Hospital (St. Leonards, NSW, Australia), between April 2004 and November 2010, in patients whose three tumour dimensions were recorded (n=103). TVol was quantified using the ellipsoidal volume formula, 4/3π(r1×r2×r3), and was correlated with clinicopathological indices/outcome. Over a median follow-up time of 20.5 months, TVol failed to significantly predict post-resection mortality [odds ratio (OR), 1.0; 95% confidence interval (CI), 0.99-1.00; P=0.438)]. Neural invasion remained an overall independent predictor of mortality following multivariate analysis (OR, 3.94; 95% CI, 1.36-11.40; P=0.011). Patients with higher TVol were more likely to require a vascular resection (P=0.007), had longer surgical times (P<0.001), larger intraoperative blood losses (P=0.007) and a trend toward worse survival (P=0.068). TVol inclusion in a multivariate model resulted in a small improvement in mortality prediction versus TSize (14.9 vs. 14.7%). A higher TVol results in a more complex perioperative course. Although TVol improved the mortality prediction beyond simple TSize alone, this difference was not significant. Studies normalising TVol for body composition are required.

Hypothyroidism after hemithyroidectomy

BACKGROUND

The risk of hypothyroidism after hemithyroidectomy is variable, and most estimates come from single institutional studies. The purpose of the present study was to determine the incidence of hypothyroidism at the population level, and to evaluate predictive factors for hypothyroidism after hemithyroidectomy.

METHODS

This retrospective study identified euthyroid patients who underwent hemithyroidectomy between 2000 and 2010 for benign disease in Kaiser Permanente Southern California regional hospitals. The incidence of hypothyroidism [thyroid stimulating hormone (TSH) levels >4 μIU/ml] was analyzed. The independent effect of age-quartile, gender, race, thyroiditis, and preoperative TSH level on the development of hypothyroidism was evaluated.

RESULTS

Of 1,240 euthyroid patients identified, 417 (34 %) developed hypothyroidism, and 314 (25 % of total group) needed levothyroxine. Hypothyroidism was more common in age-quartile 2 (32 %), age-quartile 3 (37 %), and age-quartile 4 (42 %) than in age-quartile 1 (25 %) [adjusted odds ratio (OR) = 1.87; 95 % confidence interval (CI) 1.27-2.76, p = 0.002; age-quartile 4 compared to age-quartile 1]. Hypothyroidism was more frequent with increasing preoperative TSH levels 36, 72, and 92 % in patients with TSH levels of 1.0-2, 2.01-3, and 3.01-4 μIU/ml, respectively, compared to 17 % in those with TSH levels <1 μIU/ml [adjusted OR = 45.1; 95 % CI 13.5-151, p < 0.0001; 3.01-4 μIU/ml compared to <1 μIU/ml]. Thyroiditis was also an independent predictor of hypothyroidism.

CONCLUSIONS

About one third of euthyroid patients who undergo hemithyroidectomy develop hypothyroidism. The most significant predictor is the preoperative TSH level, with an approximate doubling of risk for each 1 unit of TSH increase over 1 μIU/ml. Our categorical scale is simple and allows for easy recall when counseling patients preoperatively.

Prospective analysis of risk for hypothyroidism after hemithyroidectomy

Objectives. To evaluate risk factors and to develop a simple scoring system to grade the risk of postoperative hypothyroidism (PH). Methods. In a controlled prospective study, 109 patients, who underwent hemithyroidectomy for a benign thyroid disease, were followed up for 12 months. The relation between clinical data and PH was analyzed for significance. A risk scoring system based on significant risk factors and clinical implications was developed. Results. The significant risk factors of PH were higher TSH (thyroid-stimulating hormone) level and lower ratio of the remaining thyroid weight to the patient's weight (derived weight index). Based on the log of risk factor, preoperative TSH level greater than 1.4 mU/L was assigned 2 points; 1 point was for 0.8-1.4 mU/L. The derived weight index lower than 0.8 g/kg was assigned 1 point. A risk scoring system was calculated by summing the scores. The incidences of PH were 7.3%, 30.4%, and 69.2% according to the risk scores of 0-1, 2, and 3. Conclusion. Risk factors for PH are higher preoperative TSH level and lower derived weight index. Our developed risk scoring system is a valid and reliable tool to identify patients who are at risk for PH before surgery.

Minimally invasive thyroid nodulectomy reduces post-operative hypothyroidism when compared with thyroid lobectomy

BACKGROUND

It has been a long-standing surgical tenet that the minimum surgical procedure for a single thyroid nodule is lobectomy. Such an approach, however, has been associated with a significant incidence of post-operative hypothyroidism with patients becoming medication dependent for life. Thermal sealing devices have enabled local nodule excision to be undertaken safely with preservation of more residual thyroid mass. The aim of this study was to determine if this approach was associated with a reduction in post-operative hypothyroidism.

METHODS

This is a retrospective cohort study comprising 351 patients treated between January 2010 and December 2012. Patients were assessed at 6-8-week review. Subclinical hypothyroidism was defined as a thyroid-stimulating hormone (TSH) >4.5 mIU/L, with clinical hypothyroidism defined as both an elevated TSH and presence of clinical symptoms requiring thyroxine replacement.

RESULTS

One hundred and ninety patients underwent open thyroid lobectomy, 86 a minimally invasive thyroid lobectomy and 75 a minimally invasive nodulectomy. There was no difference in post-operative hypothyroidism after lobectomy whether by the open (22.1%) or minimally invasive (22.1%) technique. However, after minimally invasive nodulectomy, post-operative hypothyroidism was less than one quarter (5.3%) of that following lobectomy overall (22.1%, P < 0.01). There were no differences in post-operative complications between any of the groups.

CONCLUSION

Minimally invasive local nodule excision can be performed safely, with the potential for significantly reducing the rate of post-operative hypothyroidism. As such, the procedure should be considered for appropriately selected patients.

Nodular recurrence and hypothyroidism following partial thyroidectomy for benign nodular thyroid disease in children and adolescents

OBJECTIVES

Diagnostic and therapeutic processing of a thyroid nodule in children and adolescents may require lobectomy-isthmusectomy (LI) or nodule-resection (NR). Very few data in the literature report the long-term evolution of the remaining thyroid lobe in a defined pediatric population. In this study, we aimed to answer the following questions: Does a nodule recurrence occur in the remainder lobe? Is a post-operative thyroxine treatment necessary?

MATERIAL AND METHODS

This retrospective study describes 28 patients under 18 who underwent LI (22 cases) or NR (6 cases) from January 2004 to March 2012. Ten of them were lost to follow up, 18 could be assessed (4 NR (22%) and 14 LI (78%) - mean follow-up 45±31 months). All patients benefited of post-operative thyroid ultrasonography, and regular endocrinologic follow-up. The following data were analysed: emergence of new thyroid nodules, evolution of pre-existing nodules, occurrence of post-operative hypothyroidism and requirement for completion thyroidectomy.

RESULTS

The mean age at the time of surgery was 14.3±1.9 years. Two patients (11%) had pre-existing nodules in the remaining thyroid gland, none of which showed an increase in size after surgery. De novo nodules developed in five patients (27.8%). Three patients who underwent LI (21.4%) needed thyroxine treatment for post-operative hypothyroidism. One patient (5.5%) needed completion thyroidectomy.

CONCLUSIONS

In this children and adolescents population, after performing LI or NR, remaining thyroid tissue stays free of nodules in 72.2% of the cases. A post-operative thyroxin treatment is necessary in 21.4% of cases after LI.

Cost-effectiveness of FDG-PET/CT for cytologically indeterminate thyroid nodules: a decision analytic approach

CONTEXT

Patients with thyroid nodules of indeterminate cytology undergo diagnostic surgery according to current guidelines. In 75% of patients, the nodule is benign. In these patients, surgery was unnecessary and unbeneficial because complications may occur. Preoperative fluorodeoxyglucose-positron emission tomography/computed tomography (FDG-PET/CT) was found to have a very high negative predictive value (96%) and might therefore avoid futile surgery, complications, and costs. In the United States, two molecular tests of cytology material are routinely used for this purpose.

OBJECTIVE

Five-year cost-effectiveness for routine implementation of FDG-PET/CT was evaluated in adult patients with indeterminate fine-needle aspiration cytology and compared with surgery in all patients and both molecular tests.

DESIGN

A Markov decision model was developed to synthesize the evidence on cost-effectiveness about the four alternative strategies. The model was probabilistically analyzed. One-way sensitivity analyses of deterministic input variables likely to influence outcome were performed.

SETTING AND SUBJECTS

The model was representative for adult patients with cytologically indeterminate thyroid nodules.

MAIN OUTCOME MEASURES

The discounted incremental net monetary benefit (iNMB), the efficiency decision rule containing outcomes as quality-adjusted life-years and (direct) medical cost, of implementation of FDG-PET/CT is displayed.

RESULTS

Full implementation of FDG-PET/CT resulted in 40% surgery for benign nodules, compared with 75% in the conventional approach, without a difference in recurrence free and overall survival. The FDG-PET/CT modality is the more efficient technology, with a mean iNMB of €3684 compared with surgery in all. Also, compared with a gene expression classifier test and a molecular marker panel, the mean iNMB of FDG-PET/CT was €1030 and €3851, respectively, and consequently the more efficient alternative.

CONCLUSION

Full implementation of preoperative FDG-PET/CT in patients with indeterminate thyroid nodules could prevent up to 47% of current unnecessary surgery leading to lower costs and a modest increase of health-related quality of life. Compared with an approach with diagnostic surgery in all patients and both molecular tests, it is the least expensive alternative with similar effectiveness as the gene-expression classifier.

Prediction of thyroid hormone supplementation after thyroid lobectomy

BACKGROUND

Thyroid function, as assessed by thyroid-stimulating hormone (TSH) levels, was evaluated in patients after thyroid lobectomy. These assessments were analyzed against perioperative measurements to determine if any of these preoperative values were predictive of postoperative hypothyroidism and the need for postoperative levothyroxine treatment.

METHODS

In a retrospective study, data from 276 thyroid lobectomy patients were examined. These surgeries occurred over the period from January 2003-December 2012. Age, sex, volume of resected thyroid, thyroiditis, preoperative free T4, TSH, and microsomal antibody levels were analyzed for correlation with postoperative levothyroxine supplementation.

RESULTS

The overall percentage of the patients taking postoperative levothyroxine was 23.6%. The preoperative TSH level showed strong correlation with TSH levels measured 1-mo postoperatively (P < 0.001). Preoperative TSH levels >2.5 mIU/L and positive microsomal antibody showed significant correlation with postoperative levothyroxine supplementation (P < 0.001; relative risk, 8.933, and 3.438, respectively). By stratifying the patients based on preoperative TSH levels and presence of microsomal antibodies, in the low-risk group with TSH <2.5 mIU/L and negative microsomal antibody, 7% of patients received postoperative levothyroxine replacement but in the high-risk group with TSH >2.5 mIU/L and positive microsomal antibody, 77.8% required levothyroxine replacement (P < 0.001).

CONCLUSIONS

The most significant preoperative predictors for levothyroxine supplementation are preoperative TSH level and presence of microsomal antibodies. Patients with preoperative TSH <2.5 mIU/L showed a low risk of requiring postoperative levothyroxine supplementation.

Pre-operative ultrasound identification of thyroiditis helps predict the need for thyroid hormone replacement after thyroid lobectomy

OBJECTIVE

To evaluate whether pre-operative thyroiditis identified by ultrasound (US) could help predict the need for thyroid hormone replacement (THR) following thyroid lobectomy.

METHODS

Data from patients who underwent thyroid lobectomy in 2006-2011, were not taking THR pre-operatively, and had ≥1 month of follow-up were reviewed retrospectively. THR was prescribed for relatively elevated thyroid-stimulating hormone (TSH) and hypothyroid symptoms. The Kaplan-Meier method was used to estimate the percentage of patients who required THR at 6, 12, 18, and 24 months postoperatively, and Cox proportional hazards regression models were used to evaluate prognostic factors for requiring post-thyroid lobectomy THR.

RESULTS

During follow-up, 45 of 98 patients required THR. Median follow-up among patients not requiring THR was 11.6 months (range, 1.2 to 51.3 months). Six months after thyroid lobectomy, 22% of patients were taking THR (95% confidence interval [CI], 15-32%); the proportion increased to 46% at 12 months (95% CI, 36-57%) and 55% at 18 months (95% CI, 43-67%). On univariate analysis, significant prognostic factors for postoperative THR included a pre-operative TSH level >2.5 μ international units [IU]/mL (hazard ratio [HR], 2.8; 95% CI, 1.4-5.5; P = .004) and pathology-identified thyroiditis (HR, 2.4; 95% CI, 1.3-4.3; P = .005). Patients with both pre-operative TSH >2.5 μIU/mL and US-identified thyroiditis had a 5.8-fold increased risk of requiring postoperative THR (95% CI, 2.4-13.9; P<.0001).

CONCLUSION

A pre-operative TSH level >2.5 μIU/mL significantly increases the risk of requiring THR after thyroid lobectomy. Thyroiditis can add to that prediction and guide pre-operative patient counseling and surgical decision making. US-identified thyroiditis should be reported and post-thyroid lobectomy patients followed long-term (≥18 months).

Thyroid hormone replacement therapy, surveillance ultrasonography, and fine-needle aspiration after hemithyroidectomy

OBJECTIVES

We undertook a retrospective analysis of a single surgeon's experience at a tertiary care teaching hospital to determine the rates of surveillance ultrasound, fine-needle aspiration (FNA), and the need for thyroid hormone replacement therapy (THRT) after hemithyroidectomy.

METHODS

The study population comprised 120 consecutive patients who underwent hemithyroidectomy by one surgeon from January 2008 to June 2011. The medical records were reviewed for preoperative and postoperative calcium levels, fiberoptic direct laryngoscopy examination of vocal fold mobility, postoperative complications, final pathology, and postoperative follow-up.

RESULTS

Fifteen patients required completion thyroidectomy for malignancy and were excluded from the surveillance analysis. Of the remaining 105 patients, 10 (9.5%) required postoperative THRT. The likelihood for THRT was significantly associated with increased age (p = 0.01) and the presence of thyroiditis (p = 0.04). Other factors, such as gender, body mass index, residual thyroid volume, and presence of contralateral lobe nodules, were not significantly associated with this likelihood (p > 0.05). Twenty-three patients (21.9%) were followed with surveillance ultrasound, of whom 12 (11.4%) underwent FNA for nodule(s) in the contralateral lobe. Seventy-eight percent of patients did not require any long-term postoperative surveillance. There were no instances of permanent recurrent laryngeal nerve injury or hypoparathyroidism.

CONCLUSIONS

Hemithyroidectomy is an effective and efficient option for the management of benign and suspicious thyroid nodules. However, patients of increased age and/or with thyroiditis are at higher risk for postoperative hypothyroidism, and should be counseled to consider total thyroidectomy to avoid the need for long-term surveillance and the possible need for a second operation.

Is it possible to predict hypothyroidism after thyroid lobectomy through thyrotropin, thyroglobulin, anti-thyroglobulin, and anti-microsomal antibody?

Purpose

We investigated the incidence and risk factors of hypothyroidism after thyroid lobectomy, and evaluated the possibility to predict hypothyroidism preoperatively with serologic markers, such as thyrotropin (TSH), thyroglobulin (TG), anti-thyroglobulin (ATA), and anti-microsomal antibody (AMA).

Methods

We enrolled 123 consecutive patients who underwent thyroid lobectomy due to benign conditions between May 2004 and April 2008. Only preoperative euthyroid patients were included. Patients were divided into two groups by postoperative thyroid function outcomes, into hypothyroid (n = 97) and euthyroid groups (n = 26), and analyzed specially for the preoperative levels of TSH, TG, ATA, and AMA.

Results

Twenty-six (21.1%) patients developed hypothyroidism following thyroid lobectomy within 35.7 months of follow-up. The proportion of post-lobectomy hypothyroidism was high in patients with high-normal preoperative TSH level, and the cut-off value was 2.0 mIU/L, with 67% sensitivity and 75% specificity. The quantitative titer of preoperative TG, ATA, and AMA was not significant, but the outcome of categorical analysis of two or more positivities on these three markers was significantly higher in hypothyroid patients than in euthyroid patients (28.6% vs. 3.9%, P = 0.024). The combined positivity of preoperative TSH and two or more positivities of TG, ATA, and AMA possess 100% positive predictive value and 81% negative predictive value.

Conclusion

The incidence of hypothyroidism following thyroid lobectomy was 21.1%. High-normal preoperative TSH and two or more positivities for TG, ATA, and AMA are good pre-operative predictive markers. Such high-risk patients need close TSH monitoring before the onset of clinical hypothyroidism.

Clinicopathologic predictors for early and late biochemical hypothyroidism after hemithyroidectomy

BACKGROUND

Biochemical hypothyroidism (BH) after hemithyroidectomy is an under-recognized complication with a reported incidence of 9% to 43%. This study aimed to identify potential clinicopathologic risk factors associated with early (<12 months after hemithyroidectomy) and late-onset (≥12 months after hemithyroidectomy) BH.

METHODS

From 2005 to 2008 there were 263 postsurgical patients who were eligible for analysis. Serum thyroid stimulating hormone (TSH) level was checked regularly after surgery. Postoperative TSH reaching a level higher than 5.5 mIU/L was defined as BH. The overall median follow-up period was 21 months (range, 3-62 mo). Any clinicopathologic factors significantly associated with BH in the univariate analysis were entered into multivariate analysis. A further analysis was performed comparing factors between early and late-onset BH.

RESULTS

There were 38 patients who developed subsequent BH, 33 of these cases developed within 2 years. Those patients with BH were significantly older (P = .037), had a higher preoperative TSH level (P < .001), longer follow-up period (P < .001), more frequent thyroiditis on histology (P = .043), lighter resected tissue weight (P = .001), and were more likely to have positive antimicrosomal antibodies (P = .043) than those without BH. However, in the multivariate analysis after adjusting for different follow-up periods in the 2 groups, only lighter resected tissue weight (P = .036) and concomitant thyroiditis on histology (P = .005) turned out to be independent factors for BH. Thyroiditis on histology was also the only significant risk factor for developing early onset BH.

CONCLUSIONS

Patients with lighter resected tissue weight and concomitant thyroiditis on histology were particularly at risk for subsequent BH. Although not all patients with thyroiditis developed BH, in those who did develop BH it occurred within the first 11 months.

Prognosis of thyroid function after hemithyroidectomy

Identify criteria and create a risk scoring system to predict hypothyroidism after hemithyroidectomy. We have retrospectively studied 216 cases of patients with goiter who had undergone hemithyroidectomy from January 2002 to December 2007 at Vilnius University Hospital Santariškių Klinikos. Patients were divided into two groups according to their thyroid function after hemithyroidectomy: 168 (77.8%) patients’ thyroid function was normal (group A), 48 (22.2%) patients had symptoms of hypothyroidism (group B). The relationship between groups and parameters such as patients’ sex, age, patient’s weight, preoperative serum thyroid-stimulating hormone (TSH) level, weight of the remnant gland, ratio of the remaining thyroid gland weight to patient’s weight was statistically analysed. The patients’ mean age was 41.6 ± 14.1 years in group A and 52.9 ± 13.9 years in group B (p=0.0002). The mean preoperative TSH level was 0.79 ± 0.5 mU/L in group A, compared with 1.42 ± 1.00 mU/L in group B (p= 0.005). The mean ratio of the remaining thyroid gland weight to patient’s weight was 0.102 ± 0.053 g/kg in group A and 0.063 ± 0.027 g/kg in group B (p=0.04). The groups did not establish a significant difference between patients’ sex, patient’s weight or weight of the remaining gland. Patient’s age, preoperative serum TSH level, ratio of the remaining thyroid gland weight to patient’s weight is the main factors of hypothyroidism after hemithyroidectomy. A risk scoring system was created to predict hypothyroidism after hemithyroidectomy before the operation.

Detection and management of hypothyroidism following thyroid lobectomy: evaluation of a clinical algorithm

BACKGROUND

The objectives of this study were to determine: (1) the incidence permanent hypothyroidism after thyroid lobectomy (TL), (2) whether asymptomatic patients with mildly elevated thyrotropin (TSH) levels can be managed without thyroid hormone replacement, and (3) if the degree of lymphocytic infiltration (LI) and germinal center (GC) formation in the resected thyroid lobe correlates with the development of post-TL hypothyroidism.

METHODS

Subjects undergoing TL between January 2006 and January 2008 at 2 centers were enrolled in the study and thyroid function was followed prospectively based on a previously published algorithm. The histology of each resected thyroid lobe was examined, and the degree of LI and GC was quantified.

RESULTS

The study cohort consisted of 117 patients. Early postoperative TSH levels were significantly increased over preoperative levels (P < .001). TSH measured at 6 months to 1 year postoperatively, while still significantly increased over preoperative levels (P < .001), was also significantly reduced (P = .006) compared with early postoperative levels. Of the patients who presented with early postoperative hypothyroidism, 69.2% recovered to normal levels without intervention. The overall incidence of early postoperative hypothyroidism was 21.6%, and permanent hypothyroidism was 7.8%. A high degree of LI and GC correlated with a significantly higher mean TSH level (P = .003).

CONCLUSIONS

The incidence of hypothyroidism following TL is low, and a significant proportion of individuals who become biochemically hypothyroid will demonstrate only a transient elevation in their TSH levels. As well, individuals with LI, or GC formation, within their resected thyroid lobe may be at increased risk for post-TL hypothyroidism.

Subclinical hypothyroidism following hemithyroidectomy: a simple risk-scoring system using age and preoperative thyrotropin level

Hypothyroidism can be a complication after a hemithyroidectomy. The aim of this study was to determine the incidence and risk factors of hypothyroidism after a hemithyroidectomy. We also recommend a risk-scoring system that can predict post-hemithyroidectomy hypothyroidism before surgery. Among 260 patients who underwent hemithyroidectomy from January to June 2005, a total of 233 were euthryoid preoperatively and were followed for more than 3 years. Biochemical subclinical hypothyroidism developed in 57 patients (24.4%). Patients who developed postoperative hypothyroidism showed higher preoperative thyroid stimulation hormone (TSH) levels and older age. A risk-scoring system was calculated by summing the score of these 2 factors (preoperative TSH level and age). The incidences of hypothyroidism were 3, 20, 39, and 70% according to the risk scores of 0, 1, 2 and 3, respectively. Potential risk of postoperative hypothyroidism should be discussed with patients before surgery.

Thyroid hormone replacement after thyroid lobectomy

BACKGROUND

The purpose of this study was to determine the incidence of and identify risk factors for postoperative hypothyroidism in patients undergoing thyroid lobectomy.

METHODS

We retrospectively reviewed patients who underwent a thyroid lobectomy for benign disease from May 2004 to December 2007. Patients with known hypothyroidism or on preoperative thyroid hormone replacement were excluded.

RESULTS

In this study, 14.3% of patients developed hypothyroidism and required thyroid hormone supplementation. These hypothyroid patients had a higher mean pre-operative thyroid-stimulating hormone (TSH) and lower mean free thyroxine (T4) serum levels compared with euthyroid patients (TSH, 2.12 vs 1.35 microIU/mL [P = .006]; free T4, 1.03 vs 1.34 ng/dL [P = .01]). When stratified into 3 groups based on their preoperative TSH measurement (< or =1.5, 1.51-2.5, and > or =2.51 microIU/mL), the rate of hypothyroidism increased significantly at each level (13.5%, 20.5%, and 41.3%, respectively [P < .001]). In addition, patients with Hashimoto's thyroiditis were significantly more likely to become hypothyroid (odds ratio, 3.78; 95% confidence interval, 2.17-6.60).

CONCLUSION

After thyroid lobectomy, approximately 1 in 7 patients experience hypothyroidism requiring thyroid hormone treatment. Patients with preoperative TSH levels >1.5 microIU/mL, lower free T4 levels, and Hashimoto's thyroiditis are at increased risk and should be counseled and followed appropriately.