Iatrogenic hyperthyroidism does not promote weight loss or prevent ageing-related increases in body mass in thyroid cancer survivors

Thyroidectomy Effects on the Body Mass Index and Thyroid-Stimulating Hormone: A Systematic Review and Meta-Analysis

Thyroidectomy is common and is performed for malignancy, goiters with pressure symptoms, and certain types of Grave's disease. Weight and body mass index (BMI) following thyroidectomy were discussed controversially. This meta-analysis aimed to assess weight and BMI following thyroidectomy. A systematic literature search was conducted in PubMed, Medline, and Google Scholar with interest in articles that assessed body weight and BMI following total or subtotal thyroidectomy. The search engine was limited to the period from inception up to January 2024. Keywords "total thyroidectomy", "subtotal thyroidectomy", "Graves' disease", "multinodular goiter", "differentiated thyroid carcinoma", and "toxic nodules" were used. Out of the 634 articles retrieved, 89 full texts were screened, and only six studies (five retrospective and one prospective cohort) fulfilled the inclusion and exclusion criteria. No differences were evident regarding weight and BMI before and after thyroidectomy (odds ratio: -0.63, 95%CI: -1.50 to -0.24, P-value for the overall effect: 0.15; and odds ratio: -0.12, 95% CI: -0.41 to -0.16, P-value for the overall effect: 0.40 respectively). No heterogeneity was observed (I2 for heterogeneity: 0.0%). No association between thyroidectomy (when performed for differentiated thyroid carcinoma and hyperthyroidism), weight, and BMI was found. Further studies assessing thyroid-stimulating hormone (TSH) levels, radioactive iodine therapy, and thyroxine dose are needed.

Pre-surgery dietician counseling can prevent post-thyroidectomy body weight gain: results of an intervention trial

PURPOSE

It is widely accepted that patients experience weight gain after total thyroidectomy, and preventive measures should be recommended.

METHODS

A prospective study was designed to assess the efficacy of a dietetic intervention to prevent post-thyroidectomy weight gain in patients undergoing surgery for both benign and malignant thyroid conditions. Patients undergoing total thyroidectomy were prospectively and randomly assigned to receive a personalized pre-surgery diet counseling (GROUP A) or no intervention (GROUP B), according to a 1:2 ratio. All patients underwent follow-up with body-weight measurement, thyroid function evaluation and lifestyle and eating habits assessment at baseline (T0), 45 days (T1) and 12 months (T2) post-surgery.

RESULTS

The final study group encompassed 30 patients in Group A and 58 patients in Group B. The two groups were similar in terms of age, sex, pre-surgery BMI, thyroid function and underlying thyroid condition. The evaluation of body weight variations showed that patients in Group A did not experience significant body weight changes at either T1 (p = 0.127) nor T2 (p = 0.890). At difference, patients in Group B underwent a significant body weight increase from T0 to both T1 (p = 0.009) and T2 (p = 0.009). TSH levels were similar in the two groups, both at T1 and T2. Lifestyle and eating habits questionnaires failed to register any significant difference between the two groups, apart from an increase in sweetened beverages consumption in Group B.

CONCLUSIONS

A dietician counseling is effective in preventing the post-thyroidectomy weight gain. Further studies in larger series of patients with a longer follow-up appear worthwhile.

Energy balance in cancer survivors at risk of weight gain: a review

PURPOSE

The study of energy balance [i.e., energy intake (EI) and energy expenditure (EE)] is a powerful tool for understanding body weight regulation and may contribute to our understanding of rapid weight gain risk in certain cancer survivors post-diagnosis. The purpose of this review was to summarize studies that assessed longitudinal, prospective changes in components of energy balance from diagnosis/start of treatment to any duration of follow-up in cancer survivors with prior evidence of weight gain (breast, prostate, thyroid, gynecologic, testicular, and acute lymphoblastic leukemia) RESULTS: The available literature suggests that energy balance components may be altered in cancer survivors who have a heightened risk of weight gain post-diagnosis. The evidence for EI was overall inconsistent. Conversely, decreases in resting and physical activity EE during the active phases of treatment (e.g., chemotherapy, hypothyroid state) were commonly noted, which then slowly rebounded towards baseline levels at the end of treatment and during follow-up assessments. Much of this evidence is based on data collected from breast cancer survivors, which highlights a paucity of data currently available on other cancer types.

CONCLUSIONS

While there is growing acknowledgement that weight management interventions in cancer survivors are needed, it is important to recognize that changes in both behavioral (EI, physical activity EE) and passive (resting EE, thermic effect of food) components of energy balance may occur post-diagnosis. This information can help to inform weight management interventions which often entail modifications in diet and/or physical activity.

Association between Thyroid Cancer and Weight Change: A Longitudinal Follow-Up Study

BACKGROUND

The purpose of this study was to evaluate body mass index (BMI) and systolic blood pressure (SBP)/diastolic blood pressure (DBP) between Korean adults who underwent thyroidectomy and comparison groups.

METHODS

Data were included from the Korean National Health Insurance Service-Health Screening Cohort (2002-2015). BMI and SBP/DBP were measured before thyroidectomy, 1 and 2 years after thyroidectomy (n = 1995 in study I, n = 2162 in study II), comparing 1:4 matched participants (n = 7980 in study I, n = 8648 in study II). The paired t-test and linear mixed model were used to identify the differences between groups.

RESULTS

DBP in both thyroid cancer II and comparison II group were significantly lower after thyroidectomy than before thyroidectomy. However, the interaction effect of thyroidectomy in study I and study II did not reach statistical significance.

CONCLUSION

BMI, SBP and DBP were not significantly different between the thyroidectomy group and the matched comparison group.

Factors Affecting the Health-Related Quality of Life of Cancer Survivors According to Metabolic Syndrome

BACKGROUND

Cancer survivors face an increased risk of non-cancer-related deaths, particularly associated with metabolic syndrome. With increased cancer survivors having metabolic syndrome, health-related quality of life beyond cancer diagnosis and treatment has assumed greater importance.

OBJECTIVE

This study evaluated the prevalence rate of metabolic syndrome in cancer survivors. It examined the correlation between health-related quality of life and influencing factors according to the prevalence of metabolic syndrome.

METHODS

This is a cross-sectional national study using secondary data from the 2010-2018 Korean National Health and Nutrition Examination Survey by the Korea Disease Control and Prevention Agency. We analyzed a final sample of 1293 cancer survivors using multiple regression.

RESULTS

The prevalence rate of metabolic syndrome in cancer survivors was measured at 32.1%. Cancer survivors with metabolic syndrome had a lower health-related quality of life than those without it. The difference was statistically significant. Compared with cancer survivors without metabolic syndrome, those with it experienced substantial negative effects from stress, reducing health-related quality of life. Walking and muscle-building workouts had a positive effect on stress and improved quality of life.

CONCLUSIONS

Cancer survivors' metabolic syndrome should be monitored closely. Development of a customized intervention program including stress management and physical activities improves their health-related quality of life.

IMPLICATIONS FOR PRACTICE

Stress management and physical activities increase health-related quality of life among cancer survivors with metabolic syndrome; thus, healthcare providers should implement intervention programs that promote exercise engagement and stress management for this population.

Patterns of Bodyweight Changes in Patients With Hypothyroidism, a Retrospective Study From Basrah, Southern Iraq

Background

Weight gain is one of the most important hypothyroidism-related concerns in patients with hypothyroidism. However, unexpectedly, levothyroxine replacement does not necessarily result in body weight (BWT) reduction among those patients. The study aimed to assess the patterns of BWT changes through time in patients with hypothyroidism.

Method

In a retrospective database study from Faiha Specialized Diabetes, Endocrine, and Metabolism Center, a total of 346 adult patients with hypothyroidism (192 newly diagnosed and 154 known hypothyroidism patients) who had one visit every three months, five visits in one year were included. Of these, 116 new and 69 known hypothyroidism patients had completed nine visits in two years. Each visit involved thyroid-stimulating hormone (TSH) and BWT measurements. Patients with chronic liver or renal disease, diabetes mellitus, thyroid cancer, or other malignancies, pregnancy, and steroid or hormonal therapies were excluded. The patients were further subdivided based on average TSH levels into controlled (TSH ≤ 4.2 μIU/ml) and uncontrolled (TSH > 4.2 μIU/ml). Repeated measures analysis of variance (ANOVA) with a Greenhouse-Geisser correction and post hoc tests using the Bonferroni correction were used to evaluate TSH and BWT changes through the study.

Results

Both in newly diagnosed and known hypothyroidism patients with an average TSH > 4.2 μIU/mL, BWT increased significantly through visits over one and two years. For newly diagnosed patients assessed over one year (F(2.41, 321.60) = 3.28, p = 0.03), the mean BWT increase was 1.4 ± 0.38 kg from 3rd to 12th month visits (p = 0.004). For newly diagnosed patients assessed over two years (F(3.10, 263.89) = 9.08, P < 0.0005), the mean BWT increase was 3.02 ± 0.77 kg from 3rd to 24th month visits (p = 0.007). For patients with known hypothyroidism assessed over one year (F(2.56, 187.47) = 7.11, p = 0.0003), the mean BWT increase was 1.97 ± 0.64 kg at 12th month visit, and over two years (F(2.35, 77.56) = 4.67, P = 0.009), the mean BWT increase was 3.78 ± 1.26 kg at 24th month visit. While in all other patients with an average TSH ≤ 4.2 μIU/mL, the BWT changed non-significantly through the visits for newly diagnosed patients over one year and two years (p = 0.10, 0.34, respectively), and known patients over one year and two years (p = 0.47, 0.34, respectively).

Conclusion

Contrary to what is believed, adequate treatment with levothyroxine does not associate with weight reduction. Instead, either the patient kept on the same weight or continued to gain more weight.

Weight Gain After Thyroidectomy: A Systematic Review and Meta-Analysis

CONTEXT

Weight gain is a major driver of dissatisfaction and decreased quality of life in patients with hypothyroidism. Data on the changes in body weight following thyroidectomy are conflicting.

OBJECTIVE

To perform a systematic review of the literature and a meta-analysis of weight changes following total thyroidectomy.

DATA SOURCES

Literature search on PubMed.

STUDY SELECTION

Studies in English published between September 1998 and May 2018 reporting post-thyroidectomy weight changes.

DATA EXTRACTION

Data were reviewed and compared by 3 investigators; discrepancies were resolved by consensus. Meta-analyses were performed using fixed and random effect models. Univariable and multivariable meta-regression models for weight change were implemented against study follow-up, gender, and age. Exploratory subgroup analyses were performed for indication for surgery.

DATA SYNTHESIS

Seventeen studies (3164 patients) with 23.8 ± 23.6 months follow-up were included. Severe heterogeneity across studies was observed. Using a random effect model, the estimated overall weight change was a gain of 2.13 kg, 95% confidence interval (CI; 0.95, 3.30). Age was negatively associated with weight change (β = -0.238, P < 0.001). In subgroup analyses, weight gain was more evident in patients undergoing thyroidectomy for hyperthyroidism: 5.19 kg, 95% CI (3.21, 7.17) vs goiter or malignancy 1.55 kg, 95% CI (0.82, 2.27) and 1.30 kg, 95% CI (0.45, 2.15), respectively.

CONCLUSIONS

Patients undergoing thyroidectomy experience possible mild weight gain, particularly younger individuals and those with hyperthyroidism as the indication for surgery. Prospective studies directed to assess the pathophysiology of weight gain post-thyroidectomy, and to test novel treatment modalities, are needed to better characterize post-thyroidectomy weight changes.

Weight gain following treatment of hyperthyroidism-A forgotten tale

Hyperthyroidism causes weight loss in the majority, but its effect is variable and 10% of patients gain weight. Its treatment usually leads to weight gain and some studies have reported an excess weight regain. However, there is considerable inter-individual variability and a differential effect on body weight by different treatments, with some studies reporting more weight increase with radioiodine, and perhaps surgery, compared with anti-thyroid drugs. The excess weight regain may relate to treatment-induced hypothyroidism. Furthermore, the transition from hyperthyroidism to euthyroidism may unmask, or exacerbate, the predisposition that some patients have towards obesity. Other risk factors commonly implicated for such weight increase include the severity of thyrotoxicosis at presentation and underlying Graves' disease. Conflicting data exist whether lean body mass or fat mass or both are increased post-therapy and whether such increments occur concurrently or in a sequential manner; this merits clarification. In any case, clinicians need to counsel their patients regarding this issue at presentation. Limited data on the effect of dietary interventions on weight changes with treatment of hyperthyroidism are encouraging in that they cause significantly lesser weight gain compared to standard care. More research is indicated on the impact of the treatment of hyperthyroidism on various anthropometric indices and the predisposing factors for any excessive weight gain. Regarding the impact of dietary management or other weight loss interventions, there is a need for well-designed and, ideally, controlled intervention studies.

Postthyroidectomy obesity in a Korean population: does the extent of surgery matter?

Purpose

The purpose of this study was to investigate the prevalence of postthyroidectomy obesity, and the relationship between the extent of thyroidectomy and obesity.

Methods

A survey conducted at an outpatient clinic from June to October 2014 and retrospective charts for patients undergoing thyroidectomy at Konkuk University Medical Centers from June 2009 to December 2013 were reviewed. We compared clinical characteristics and pre- and postoperative obesity-related factors in 227 patients who underwent total thyroidectomy or lobectomy.

Results

Patients included 39 males and 188 females with a mean age of 46.0 ± 11.0 years; the mean follow-up period was 23.9 ± 16.7 months, and 90 of the 227 patients showed postthyroidectomy obesity. In effect of operative extent on postoperative obesity, patients who underwent TT (48.2 years) than those who underwent lobectomy (43.4 years). TT group had longer follow-up and the frequency of menopause was higher than in the lobectomy group. No differences in postthyroidectomy obesity, body weight change, or body mass index (BMI), change among 2 groups. The predictors of postthyroidectomy obesity were older age, female, heavy alcohol consumption (P = 0.029), higher preoperative BMI (P < 0.001), larger postoperative weight gain (P = 0.024), and larger BMI change. However, the extent of thyroidectomy did not affect postthyroidectomy obesity. Preoperative BMI (P < 0.001) and heavy alcohol consumption (P = 0.03) were independent factors of postthyroidectomy obesity.

Conclusion

The extent of thyroidectomy does not affect postthyroidectomy obesity. Preoperative BMI and heavy alcohol consumption are risk factors for postthyroidectomy obesity. Studies are needed to suggest preoperative life style modification to prevent postthyroidectomy obesity.

Weight Changes After Thyroid Surgery for Patients with Benign Thyroid Nodules and Thyroid Cancer: Population-Based Study and Systematic Review and Meta-Analysis

BACKGROUND

A key concern among patients who undergo thyroid surgery is postoperative weight gain. Yet, the impact of thyroid surgery on weight is unclear.

METHODS

The population-based Rochester Epidemiology Project was used to examine weight and body mass index (BMI) changes at one, two, and three years of follow-up in (i) patients with thyroid cancer and benign thyroid nodules after thyroid surgery, and (ii) patients with thyroid nodules who did not have surgery. A comprehensive systematic review of the published literature from inception to February 2016 was also conducted. The results were pooled across studies using a random effects model.

RESULTS

A total of 435 patients were identified: 181 patients with thyroid cancer who underwent surgery (group A), 226 patients with benign thyroid nodules without surgery (group B), and 28 patients with benign thyroid nodules undergoing surgery (group C). Small changes in mean weight, BMI, and the number of patients whose weight increased between 5 and 10 kg were similar during each year of follow-up between patients in groups A and B. Furthermore, age >50 years, female sex, baseline BMI >25 kg/m², and thyrotropin value at one to two years were not predictors of a 5% weight change. In the meta-analysis, 11 studies were included. One to two years after surgery for thyroid cancer or thyroid nodules, patients gained on average 0.94 kg [confidence interval (CI) 0.58-1.33] and 1.07 kg [CI 0.26-1.87], respectively. Patients with benign thyroid nodules who did not have surgery gained 1.50 kg [CI 0.60-2.4] at the longest follow-up.

CONCLUSIONS

On average, patients receiving care for thyroid nodules or cancer gain weight, but existing evidence suggests that surgery for these conditions does not contribute significantly to further weight gain. Clinicians and patients can use this information to discuss what to expect after thyroid surgery.

Interplay between Body Size Measures and Thyroid Cancer Aggressiveness: A Retrospective Analysis

Considering controversial data about the relationship between body size and prognosis of differentiated thyroid cancer (DTC), the current study aimed to assess the influence of body weight, body mass index (BMI), and body surface area (BSA) on DTC. We conducted a retrospective analysis of patients' records from the Thyroid Cancer Unit, assessing body size measures, clinical and laboratory prognostic factors, and disease evolution. 337 patients, aged 45.95 ± 13.04 years old, with BMI of 27.87 ± 5.13 kg/m² and BSA of 1.74 ± 0.18 m² were enrolled. After 9.5 ± 6.9 years of follow-up, 87.29% of patients were disease-free and 12.71% had persistent disease; no patient had deceased. Patients aged <45 years old with extrathyroidal invasion tumor had greater baseline body weight and BSA than those without extrathyroidal invasion (median 79.5 kg versus 67 kg and 1.85 m² versus 1.74 m²). Women with poorly differentiated tumor and patients aged ≥45 years old with distant metastasis presented greater weight loss during follow-up compared to patients without such characteristics (median -2 kg versus +1.5 kg and -3 kg versus +1 kg, respectively). The relationship between body size and DTC evolution was not observed. In conclusion, higher weight and BSA were associated with a greater chance of extrathyroidal tumor invasion in younger patients. Specific subgroups of patients with aggressive disease presented higher weight loss. Young patients with higher BSA should be carefully treated due to possible worse prognosis related to increased incidence of extrathyroid invasion. Findings related to tumor aggressiveness and weight loss in specific groups deserve further mechanistic studies.

Does the Risk of Metabolic Syndrome Increase in Thyroid Cancer Survivors?

BACKGROUND

The steep rise in thyroid cancer observed in recent decades has caused an increase in the population of long-term thyroid cancer survivors. Other than recurrences of cancer, the long-term health consequences of surviving thyroid cancer, particularly metabolic syndrome, have not yet been determined. The aim of this study was to estimate the risk of metabolic syndrome in thyroid cancer survivors.

MATERIALS AND METHODS

Population-based data from the Korean National Health and Nutrition Examination Survey (KNHANES) were used for the analysis. The data of KNHANES IV-VI from 2007-2014 were obtained. After excluding subjects who were under 19 years old, whose fasting interval was less than 8 hours, and whose data for predefined variables including metabolic syndrome components were incomplete, 34,347 subjects were analyzed. The incidence of metabolic syndrome and its components were evaluated in three groups: subjects with no history of thyroid cancer, subjects diagnosed with thyroid cancer within 3 years of the survey date, and subjects diagnosed more than 3 years before the survey date.

RESULTS

Thyroid cancer diagnoses were made within 3 years of the survey date for 95 subjects (group 1, short-term survivors) and more than 3 years earlier than the survey date for 60 subjects (group 2, long-term survivors). Metabolic syndrome was frequently observed with clinical significance (odds ratio [OR] 1.986 [95% confidence interval [CI] 1.0-3.70], p = 0.030) in short-term survivors compared with subjects with no thyroid cancer history. Risks for having high blood pressure and high fasting glucose were estimated to be higher in the short-term survivor group (OR 2.115 [CI 1.23-3.64], p = 0.006 and OR 1.792 [CI 1.03-3.11], p = 0.038, respectively). No significant associations were noticed in the long-term survivor group when compared with the group with no thyroid cancer history.

CONCLUSION

Risks for metabolic syndrome, especially high blood pressure and high fasting glucose, were increased in short-term survivors of thyroid cancer but not in long-term survivors when compared with subjects with no history of thyroid cancer.

Assessing perioperative body weight changes in patients thyroidectomized for a benign nontoxic nodular goitre

BACKGROUND

Following thyroidectomy, patients often complain of weight gain. Our study aimed to evaluate the extent of weight change in patients thyroidectomized for a nontoxic benign goitre after adjusting for patient demographics and pre-operative weight changes.

METHODS

Three different patient groups were studied. The first comprised 898 patients who underwent thyroidectomy for benign nontoxic nodular goitre (group I). The second comprised 179 patients who had benign nontoxic goitre but did not undergo thyroidectomy (group II), and the third comprised 80 patients who underwent a simple excision of a parathyroid adenoma (group III). All patients were weighed 12 months preceding baseline, at baseline and 6 months after baseline.

RESULTS

Baseline characteristics were comparable between groups. Patients in Group I who gained the least weight in the year leading to surgery gained the most weight 12 months after surgery (P = 0·030). After adjusting for demographics and pre-operative weight changes, Group I gained significantly more weight at post 6 and 12 months (0·71 (95% CI=0·46-0·95) kg and 1·21 (95% CI = 0·96-1·46) kg, respectively). Weight gain at post 12 months appeared similar between hemithyroidectomy and total thyroidectomy (1·32 vs 1·16 kg, P = 0·197). Younger age (ß coefficient -0·100, 95% CI = -0·030 to 0·003, P = 0·015) and higher baseline thyroid stimulating hormone (ß coefficient -0·315, 95% CI = -1·468 to 0·134, P = 0·020) were significant factors for weight gain at post 12 months.

CONCLUSIONS

Compared to nonthyroidectomized patients, thyroidectomized patients experienced significant weight increases at post 6 and 12 months. The extent of thyroidectomy did not affect the extent of weight gain. Younger age and higher baseline thyroid stimulating hormone were significant factors of weight gain at post 12 months.

Effects of Levothyroxine Replacement or Suppressive Therapy on Energy Expenditure and Body Composition

BACKGROUND

Thyrotropin (TSH)-suppressive doses of levothyroxine (LT4) have adverse effects on bone and cardiac function, but it is unclear whether metabolic function is also affected. The objective of this study was to determine whether women receiving TSH-suppressive LT4 doses have alterations in energy expenditure or body composition.

METHODS

This study was a cross-sectional comparison between three groups of women: 26 women receiving chronic TSH-suppressive LT4 doses, 80 women receiving chronic replacement LT4 doses, and 16 untreated euthyroid control women. Subjects underwent measurements of resting energy expenditure (REE), substrate oxidation, and thermic effect of food by indirect calorimetry; physical activity energy expenditure by accelerometer; caloric intake by 24-hour diet recall; and body composition by dual X-ray absorptiometry.

RESULTS

REE per kilogram lean body mass in the LT4 euthyroid women was 6% lower than that of the LT4-suppressed group, and 4% lower than that of the healthy control group (p = 0.04). Free triiodothyronine (fT3) levels were directly correlated with REE, and were 10% lower in the LT4 euthyroid women compared with the other two groups (p = 0.007). The groups of subjects did not differ in other measures of energy expenditure, caloric intake, or body composition.

CONCLUSIONS

LT4 suppression therapy does not adversely affect energy expenditure or body composition in women. However, LT4 replacement therapy is associated with a lower REE, despite TSH levels within the reference range. This may be due to lower fT3 levels, suggesting relative tissue hypothyroidism may contribute to impaired energy expenditure in LT4 therapy.

A Clinical Framework to Facilitate Risk Stratification When Considering an Active Surveillance Alternative to Immediate Biopsy and Surgery in Papillary Microcarcinoma

BACKGROUND

The 2015 American Thyroid Association thyroid cancer management guidelines endorse an active surveillance management approach as an alternative to immediate biopsy and surgery in subcentimeter thyroid nodules with highly suspicious ultrasonographic characteristics and in cytologically confirmed very low risk papillary thyroid cancer (PTC). However, the guidelines provide no specific recommendations with regard to the optimal selection of patients for an active surveillance management approach. This article describes a risk-stratified clinical decision-making framework that was developed by the thyroid cancer disease management team at Memorial Sloan Kettering Cancer Center as the lessons learned from Kuma Hospital in Japan were applied to a cohort of patients with probable or proven papillary microcarcinoma (PMC) who were being evaluated for an active surveillance management approach in the United States.

SUMMARY

A risk-stratified approach to the evaluation of patients with probable or proven PMC being considered for an active surveillance management approach requires an evaluation of three interrelated but distinct domains: (i) tumor/neck ultrasound characteristics (e.g., size of the primary tumor, the location of the tumor within the thyroid gland); (ii) patient characteristics (e.g., age, comorbidities, willingness to accept observation); and (iii) medical team characteristics (e.g., availability and experience of the multidisciplinary team). Based on an analysis of the critical factors within each of these domains, patients with probable or proven PTC can then be classified as ideal, appropriate, or inappropriate candidates for active surveillance.

CONCLUSION

Risk stratification utilizing the proposed decision-making framework will improve the ability of clinicians to recognize individual patients with proven or probable PMC who are most likely to benefit from an active surveillance management option while at the same time identifying patients with proven or probable PMC that would be better served with an upfront biopsy and surgical management approach.

Weight Changes in Patients with Differentiated Thyroid Carcinoma during Postoperative Long-Term Follow-up under Thyroid Stimulating Hormone Suppression

BACKGROUND

There are limited data about whether patients who receive initial treatment for differentiated thyroid cancer (DTC) gain or lose weight during long-term follow-up under thyroid stimulating hormone (TSH) suppression. This study was aimed to evaluate whether DTC patients under TSH suppression experience long-term weight gain after initial treatment. We also examined the impact of the radioactive iodine ablation therapy (RAIT) preparation method on changes of weight, comparing thyroid hormone withdrawal (THW) and recombinant human TSH (rhTSH).

METHODS

We retrospectively reviewed 700 DTC patients who underwent a total thyroidectomy followed by either RAIT and levothyroxine (T4) replacement or T4 replacement alone. The control group included 350 age-matched patients with benign thyroid nodules followed during same period. Anthropometric data were measured at baseline, 1 to 2 years, and 3 to 4 years after thyroidectomy. Comparisons were made between weight and body mass index (BMI) at baseline and follow-up.

RESULTS

Significant gains in weight and BMI were observed 3 to 4 years after initial treatment for female DTC but not in male patients. These gains among female DTC patients were also significant compared to age-matched control. Women in the THW group gained a significant amount of weight and BMI compared to baseline, while there was no increase in weight or BMI in the rhTSH group. There were no changes in weight and BMI in men according to RAIT preparation methods.

CONCLUSION

Female DTC patients showed significant gains in weight and BMI during long-term follow-up after initial treatment. These changes were seen only in patients who underwent THW for RAIT.

RAI thyroid bed uptake after total thyroidectomy: A novel SPECT-CT anatomic classification system

OBJECTIVE

Recent, more selective use of radioactive iodine (RAI) has led to reevaluation of the clinical importance of achieving complete total thyroidectomy with minimal residual normal thyroid tissue. We utilize the improved localization by post-RAI remnant ablation, single photon emission computerized tomography-computed tomography (SPECT-CT) to define specific anatomic sites of residual RAI-uptake foci after total thyroidectomy for differentiated thyroid cancer (DTC) and to provide a novel classification system relating uptake to thyroid anatomy and preservation of adjacent neural structures.

STUDY DESIGN

Retrospective.

METHOD

Radioactive iodine-uptake foci in thyroid bed were localized by SPECT/CT imaging at the time of RAI remnant ablation in 141 DTC patients undergoing total thyroidectomy.

RESULTS

Minimal residual RAI uptake (median 0.32% at 24 hours) in the thyroid bed was detected by diagnostic planar whole body scans in 93% and by posttherapy SPECT/CT imaging in 99% of subjects. Discrete RAI uptake foci were identified on the SPECT/CT imaging at Berry's ligament (87%), at superior thyroid poles (79%), in paratracheal-lobar regions (67%), in isthmus-region (54%), and in pyramidal lobe (46%). Despite the residual foci, the nonstimulated thyroglobulin (Tg) prior to remnant ablation (with a median thyroid-stimulating hormone of 0.36 m IU/L) was < 0.6 ng/mL in 53% and < 1 ng/mL in 73% of cases.

CONCLUSION

After extracapsular total thyroidectomy, highly sensitive detection tools identify microscopic residual RAI avid foci in thyroid bed in the majority of patients. These foci can be classified as 1) neural-related and 2) capsule-related. These common residual foci have no relationship to postoperative Tg, suggesting that attempts at radical removal of thyroid tissue in these locations may not be warranted.

LEVEL OF EVIDENCE

4.

Environmental, lifestyle, and anthropometric risk factors for differentiated thyroid cancer in cuba: a case-control study

BACKGROUND

The incidence of differentiated thyroid carcinoma (DTC) is low in people of African origin and higher in populations living on islands, but there is no well-established explanation for these differences. Cuba is a multiethnic nation with people of African and Spanish descent. Until now, no study on the risk factors of DTC has focused on the Cuban population. Our aim is to establish the role of environmental and lifestyle factors and to relate anthropometric measurements to the risk of developing DTC in Cuba.

METHODS

We performed a case-control study of 203 DTC patients treated in two hospitals in Havana and 212 controls living in the area covered by these hospitals (i.e. parts of Havana and the municipality of Jaruco). Risk factors were analyzed using conditional logistic regression.

RESULTS

As has been shown by other studies, we found that non-African ethnicity, never smoking, parity, and high body mass index are risk factors significantly associated with DTC, whereas a history of exposure to ionizing radiation and level of education were not significantly related with disease development. Being rhesus factor-positive, having a personal history of benign thyroid disorder, agricultural occupation, and consumption of artesian well water were also associated with a significantly increased risk of developing DTC.

CONCLUSIONS

The original findings reported here concern the risk of DTC that was associated with non-African ethnicity, positive rhesus factor, farming, and drinking water from an artesian well.

Thyroid hormone and obesity

PURPOSE OF REVIEW

To review several of the most recent and most important clinical studies regarding the effects of thyroid treatments on weight change, associations between thyroid status and weight, and the effects of obesity and weight change on thyroid function.

RECENT FINDINGS

Weight decreases following treatment for hypothyroidism. However, following levothyroxine treatment for overt hypothyroidism, weight loss appears to be modest and mediated primarily by loss of water weight rather than fat. There is conflicting evidence about the effects of thyroidectomy on weight. In large population studies, even among euthyroid individuals, serum thyroid-stimulating hormone is typically positively associated with body weight and BMI. Both serum thyroid-stimulating hormone and T3 are typically increased in obese compared with lean individuals, an effect likely mediated, at least in part, by leptin. Finally, there is no consistent evidence that thyroid hormone treatment induces weight loss in obese euthyroid individuals, but thyroid hormone analogues may eventually be useful for weight loss.

SUMMARY

The interrelationships between body weight and thyroid status are complex.