The incidence of papillary thyroid carcinoma and outcomes in operative patients according to their body mass indices

Sex-dependent impact of obesity on aggressiveness of papillary thyroid cancer

PURPOSE

To investigate the impact of body mass index (BMI) on the aggressiveness of papillary thyroid cancer (PTC).

METHODS

A total of 1720 PTC patients with total thyroidectomy or lobectomy, from January 2017 to April 2020, were retrospectively evaluated. Based on BMI, they were divided into two groups, as follows: control (CON, < 24 kg/m2) and overweight and obesity (OB, ≥ 24 kg/m2), each sex being analyzed separately.

RESULTS

In the whole cohort, the OB group had significantly higher rates of extrathyroidal extension (21.5 vs. 16.8%, p = 0.013), multifocality (43.2 vs. 37.7%, p = 0.018), and BRAF-V600E mutation (82.9 vs. 79.3%, p = 0.015) than the CON group. In males, the OB group had increased rates of tumor size over 1cm (54.4 vs. 42.7%, p = 0.008), extrathyroidal extension (24.9 vs. 12.4%, p = 0.001), and multifocality (42.7 vs. 33.5%, p = 0.038). The OB group had significantly higher adjusted odds ratios (ORs) of 1.63 (1.14-2.33, p = 0.008), 2.12 (1.26-3.57, p = 0.005), and 1.56 (1.07-2.29, p = 0.022) for tumor size over 1cm, extrathyroidal extension, and multifocality compared with CON. Additionally, overweight and obesity were analyzed alone and the rates of extrathyroidal extension (30/100, 30.0%, p = 0.001) and tumor size over 1cm (65/100, 65.0%, p = 0.001) were significantly higher in the obesity group than in the overweight and CON groups. The obesity group had robust higher adjusted ORs of 2.51(1.50-4.20, p < 0.001), 2.93 (1.50-5.73, p = 0.002) and 1.89 (1.11-3.22, p = 0.020) for tumor size over 1cm, extrathyroidal extension, and multifocality compared with CON.

CONCLUSIONS

Overweight and obesity were predominant independent risk factors for PTC aggressiveness in males. These data indicated that the therapeutic treatment should be based on risk stratification by BMI in males.

Development and validation of prediction models for papillary thyroid cancer structural recurrence using machine learning approaches

BACKGROUND

Although papillary thyroid cancer (PTC) patients are known to have an excellent prognosis, up to 30% of patients experience disease recurrence after initial treatment. Accurately predicting disease prognosis remains a challenge given that the predictive value of several predictors remains controversial. Thus, we investigated whether machine learning (ML) approaches based on comprehensive predictors can predict the risk of structural recurrence for PTC patients.

METHODS

A total of 2244 patients treated with thyroid surgery and radioiodine were included. Twenty-nine perioperative variables consisting of four dimensions (demographic characteristics and comorbidities, tumor-related variables, lymph node (LN)-related variables, and metabolic and inflammatory markers) were analyzed. We applied five ML algorithms-logistic regression (LR), support vector machine (SVM), extreme gradient boosting (XGBoost), random forest (RF), and neural network (NN)-to develop the models. The area under the receiver operating characteristic (AUC-ROC) curve, calibration curve, and variable importance were used to evaluate the models' performance.

RESULTS

During a median follow-up of 45.5 months, 179 patients (8.0%) experienced structural recurrence. The non-stimulated thyroglobulin, LN dissection, number of LNs dissected, lymph node metastasis ratio, N stage, comorbidity of hypertension, comorbidity of diabetes, body mass index, and low-density lipoprotein were used to develop the models. All models showed a greater AUC (AUC = 0.738 to 0.767) than did the ATA risk stratification (AUC = 0.620, DeLong test: P < 0.01). The SVM, XGBoost, and RF model showed greater sensitivity (0.568, 0.595, 0.676), specificity (0.903, 0.857, 0.784), accuracy (0.875, 0.835, 0.775), positive predictive value (PPV) (0.344, 0.272, 0.219), negative predictive value (NPV) (0.959, 0.959, 0.964), and F1 score (0.429, 0.373, 0.331) than did the ATA risk stratification (sensitivity = 0.432, specificity = 0.770, accuracy = 0.742, PPV = 0.144, NPV = 0.938, F1 score = 0.216). The RF model had generally consistent calibration compared with the other models. The Tg and the LNR were the top 2 important variables in all the models, the N stage was the top 5 important variables in all the models.

CONCLUSIONS

The RF model achieved the expected prediction performance with generally good discrimination, calibration and interpretability in this study. This study sheds light on the potential of ML approaches for improving the accuracy of risk stratification for PTC patients.

TRIAL REGISTRATION

Retrospectively registered at www.chictr.org.cn (trial registration number: ChiCTR2300075574, date of registration: 2023-09-08).

Thyroidectomy Outcomes in Obese Patients

INTRODUCTION

Obese patients often have higher complication rates after elective general surgeries; however, few studies have examined the outcomes after thyroidectomy. This study examines whether increased body mass index (BMI) is associated with poor postoperative outcomes after thyroid surgery.

METHODS

A retrospective review of patients who underwent thyroidectomy from 2015 to 2018 was performed. Demographics, comorbidities, pathology, and extent of resection (total versus hemithyroidectomy) were examined. Patients were classified into BMI groups according to the WHO definitions, and the incidence of surgical outcomes was determined in each group. Surgical outcomes of interest included readmission rates (RRs), length of stay, average operating room time, return to the operating room, hypocalcemia, postop infections, hematomas, and recurrent laryngeal nerve injury. Between-subjects statistics including independent samples t-test, ANOVA, and chi-square analyses were performed.

RESULTS

There were n = 465 patients included with a mean BMI 32.35 (standard deviation = 8.55) and median BMI 30.78 (Q1 = 26.26, Q3 = 36.73). There were no differences between BMI groups in age, gender, smoking, heart disease. There was a positive association between increased BMI and postoperative infection (P < 0.001), pneumonia (P = 0.018), and surgical site infection (P = 0.04), which were highest for BMI > 40. Increased BMI was associated with a higher 30-d RR (P = 0.008), particularly for BMI >40 versus BMI <40 (6.2% versus 1.05%; P = 0.003). There were no significant differences between surgical outcomes for patients with increased BMI who underwent total thyroidectomy or hemithyroidectomy.

CONCLUSIONS

Excellent postoperative outcomes were observed in all BMI categories. Higher postoperative infection and 30-d RRs were observed in the morbidly obese. Contrary to previous studies, operating room times were similar regardless of BMI.

The impact of obesity on thyroidectomy outcomes: a case-matched study

Obesity is a well-known public health concern in Western World. Accordingly, an elevated number of obese patients undergo thyroidectomy every year. We aim to assess the impact of obesity on intraoperative and postoperative outcomes of patients who undergo thyroidectomy. 1228 patients underwent thyroidectomy at our department between January 2021 and September 2021. We divided patients into two groups according to body mass index (BMI): non-obese (BMI < 30 kg/m2) and obese (BMI ≥ 30 kg/m2). A propensity score approach was performed to create 1:1 matched pairs (matching according to age, gender, diagnosis, nodule size and type of operation). After matching, the final population included 522 patients, equally divided between each group: non-obese group (Group A; n = 261) and obese group (Group B; n = 261). The primary endpoint of the study was the overall rate of postoperative complications; secondary endpoints of the study were operative time, use of energy device and length of hospital stay. The duration of hospital stay resulted longer in Group B (p = 0.002). No statistically significant differences were documented in terms of operative time (p = 0.206), use of energy devices (p = 0.855) and surgical complications (p = 0.429). Moreover, no statistically significant differences were documented considering each specific complication: transient and permanent hypocalcemia (p = 0.336; p = 0.813, respectively), transient and permanent recurrent laryngeal nerve palsy (p = 0.483; p = 0.523, respectively), hematoma (p = 0.779), bleeding (p = 0.178), wound infection (p = 0.313) and cheloid formation (p = 0.412). Thyroidectomy can safely be performed in obese patients. Outcomes resulted comparable; nonetheless, obesity correlates to longer hospital stay.

Potential impact of obesity on the aggressiveness of low- to intermediate-risk papillary thyroid carcinoma: results from a MASTER cohort study

PURPOSE

Obesity is associated with an increased risk of papillary thyroid carcinoma (PTC). Evidence of the impact of obesity on PTC aggressiveness is scarce. We aimed to evaluate the association between the body mass index (BMI) and the presence of aggressive features of low- to intermediate-risk PTC in a prospective cohort.

METHODS

We prospectively enrolled 1,032 patients with low- to intermediate-risk PTC who underwent lobectomy at 22 hospitals in Korea and divided into three groups according to BMI, as follows: normal/underweight ( < 23 kg/m2), overweight (23-24.9 kg/m2), and obese ( ≥ 25 kg/m2). Clinicopathological features of PTC at diagnosis were evaluated.

RESULTS

Obese patients had a higher rate of macro-PTC ( > 1 cm) and greater incidence of extra-thyroidal extension (ETE), vascular invasion, and intermediate-risk tumors than those not classified as obese. Increased BMI was positively associated with the incidence of macro-PTC, ETE, vascular invasion, and intermediate-risk category. After adjusting for age, sex, pathological features, metabolic syndrome, thyroid function test, and smoking habits, obesity was a risk factor for ETE (odds ratio [OR] = 1.7, 95% confidence interval [CI]: 1.2-2.5, p = 0.005) and intermediate-risk PTC (OR = 1.7, 95% CI: 1.1-2.5, p = 0.011) in women. The association between obesity and ETE was significant regardless of whether or not women had metabolic syndrome. There was no significant association between obesity and aggressive PTC features in men.

CONCLUSION

BMI at the time of thyroid cancer diagnosis may affect the aggressiveness of low- to intermediate-risk PTC, especially in women.

Association of Body Mass Index With Clinicopathological Features of Papillary Thyroid Carcinoma: A Retrospective Study

OBJECTIVE

We examined the effect of body mass index (BMI) on clinicopathological features of papillary thyroid carcinoma (PTC).

METHODS

The clinical data of 4476 patients with PTC who underwent surgical treatment were retrospectively analyzed. According to the different BMI of patients, it can be divided into underweight (BMI < 18.5 kg/m²), normal weight (18.5 ≤ BMI < 24.0 kg/m²), overweight (24 ≤ BMI < 28 kg/m²), and obese (BMI ≥ 28 kg/m²). Spearman correlation analysis was performed to assess the relationship between the BMI and the size of PTC tumor. Multivariate binary logistic regression analysis was performed to estimate the association of overweight and obesity with clinicopathological features of PTC.

RESULTS

There was a positive correlation between the BMI and PTC tumor size (r = 0.087, P < .001). As compared with normal weight patients with PTC, overweight and obese patients with PTC had a greater risk of bilaterality (odds ratio [OR] = 1.295, OR = 1.669), multifocality (OR = 1.273, OR = 1.617), extrathyroidal extension (OR = 1.560, OR = 2.477), T (3 + 4) stage (OR = 1.482, OR = 2.392), and recurrence risk (intermediate-high risk) (OR = 1.215, OR = 1.718) (P < .05 for all). As compared with normal weight patients with papillary thyroid microcarcinoma (PTMC), overweight and obese patients with PTMC had a greater risk of bilaterality (OR = 1.341, OR = 1.737), multifocality (OR = 1.244, OR = 1.640), extrathyroidal extension (OR = 1.992, OR = 2.080), T (3 + 4) stage (OR = 1898, OR = 2.039), and recurrence risk (intermediate-high risk) (OR = 1.458, OR = 1.536) (P < .05 for all).

CONCLUSION

Overweight and obesity were significantly associated with aggressive clinicopathological features of PTC and PTMC. The impact of overweight and obesity should be considered when choosing treatment decisions for PTC and PTMC.

Current Controversies in Low-Risk Differentiated Thyroid Cancer: Reducing Overtreatment in an Era of Overdiagnosis

CONTEXT

Low-risk differentiated thyroid cancer (DTC) is overdiagnosed, but true incidence has increased as well. Owing to its excellent prognosis with low morbidity and mortality, balancing treatment risks with risks of disease progression can be challenging, leading to several areas of controversy.

EVIDENCE ACQUISITION

This mini-review is an overview of controversies and difficult decisions around the management of all stages of low-risk DTC, from diagnosis through treatment and follow-up. In particular, overdiagnosis, active surveillance vs surgery, extent of surgery, radioactive iodine (RAI) treatment, thyrotropin suppression, and postoperative surveillance are discussed.

EVIDENCE SYNTHESIS

Recommendations regarding the diagnosis of DTC, the extent of treatment for low-risk DTC patients, and the intensity of posttreatment follow-up have all changed substantially in the past decade. While overdiagnosis remains a problem, there has been a true increase in incidence as well. Treatment options range from active surveillance of small tumors to total thyroidectomy followed by RAI in select cases. Recommendations for long-term surveillance frequency and duration are similarly broad.

CONCLUSION

Clinicians and patients must approach each case in a personalized and nuanced fashion to select the appropriate extent of treatment on an individual basis. In areas of evidential equipoise, data regarding patient-centered outcomes may help guide decision-making.

Understanding the effect of obesity on papillary thyroid cancer: is there a need for tailored diagnostic and therapeutic management?

INTRODUCTION

Several studies have focused on the relationship between obesity and differentiated thyroid carcinoma (DTC), particularly papillary histotype (PTC). However, the association of obesity with both incidence and aggressiveness of PTC is still incompletely understood.

AREAS COVERED

We reviewed the mechanisms underlying the cross talk between obesity and thyroid carcinomas and described the most recent evidence evaluating the effect of obesity on the development of PTC, as well as the impact of excessive body weight on the clinicopathologic features and outcome of this type of cancer.

EXPERT OPINION

Available evidence suggests that excessive body weight is linked with a higher risk of getting PTC, while its impact on the aggressiveness of the disease, if present, is still not clear. Therefore, while attention should be paid to discover thyroid cancer in patients with obesity earlier, once diagnosed it should be managed following a conventional workup as in normal weight patients, based on the clinical presentation of the disease and including active surveillance if appropriate, as recommended by referral guidelines.

Analysis of Risk Factors for Phonation Disorders after Thyroid Surgery

Phonation disorders after thyroidectomy are among the most common complications and occur as a result of recurrent laryngeal nerve (RLN) injury. The multivariate analysis of risk factors for phonation disorders after thyroidectomy was assessed. A group of 830 patients with 1500 RLNs at risk of injury during thyroidectomy were analyzed retrospectively. The impact of the method of RLN identification, age, sex, BMI, kind of thyroid surgery, pathology, surgeon’s experience and thyroid volume on vocal cord paralysis was analyzed. We found that the retrosternal goiter and the volume above 100 mL were the most important risk factors for both transient and permanent paralysis. Thyroid cancer had a statistically significant impact on the increase in permanent paralysis, while this indication had practically no impact on transient paralysis. Among patients over 65 years with obesity, the probability of transient complications approximately doubled, with no effect on the permanent paralysis. Men were approximately 1.7 times more likely to develop any type of phonation disorder. Secondary operations more than doubled the risk of transient and permanent vocal cord paralysis. Thyroidectomy with only visual RLN identification was associated with a risk of both transient and permanent vocal cord paralysis almost two times higher, compared to neuromonitoring.

The association of obesity with thyroid carcinoma risk

Background

The prevalence of obesity and an increased incidence of thyroid carcinoma (TC) threaten public health in parallel on a global scale. Sufficient evidence supports excess body fatness in thyroid carcinogenesis, and the role and anthropometric markers of obesity have been causally associated with the rising risk of TC.

Methods

A literature search was conducted in PubMed. Studies focused on the effect of obesity in TC.

Results

This review mainly discusses the global incidence and prevalence of obesity‐related TC. We also review the role of obesity in TC and potential clinical strategies for obesity‐related TC.

Conclusions

Excess body fatness in early life and TC survival initiate adverse effects later in life.

The incidence of thyroid cancer has been increasing in the last decades all over the world. Such a steady growth cannot be entirely attributable to more sensitive diagnostic procedures. Obesity has increased with sufficient rapidity in the same time frame and may as possible promoters and modifiable risk factors for thyroid cancer in recent years. The aim of this review was to focus on the relationship between obesity and the risk of thyroid cancer. Obesity seems to play a relevant role in thyroid cancer carcinogenesis as well as in its severity and aggressiveness. The possible underlying mechanism is involved chronic inflammation mediated by cytokines, leptin, and adiponectins.

The Relationship Between Body Mass Index and Different Regional Patterns of Lymph Node Involvement in Papillary Thyroid Cancers

Introduction

Lymph node (LN) metastasis is the first site of metastasis of papillary thyroid cancer (PTC). LN status influences clinical management and the prognosis of patients. We explored the relationship between patient obesity and regional patterns of LN involvement in PTC.

Materials and Methods

This study retrospectively analyzed the data from 12,772 PTC patients. The rate of LN metastasis, number of LN metastasis, maximum diameter of positive LN, number of dissected LN, and LN ratios (LNR) were compared between normal-weight and obese patients. Statistical methods have been adjusted for the confounders in hypothesis testing.

Results

Overweight and obesity were independent risk factor for metastatic LNs (OR₁ = 1.125, 95% CI 1.042-1.214, P₁ = 0.003; OR₂ = 1.554, 95% CI 1.339-1.802, P₂<0.001). Obesity was an independent risk factor for the number of metastatic CLNs (OR=1.159, 95% CI 0.975-1.377, P=0.045), however not for number of metastatic lateral LNs (P=0.907). Furthermore, obesity was not an independent risk factor for number of CLNs when dissected more than five (P=0.653), still an independent risk factors for number of metastatic lateral LNs when more than six (OR=1.185, 95% CI 1.010-1.391, P=0.037). As for LNR, obesity was an independent risk factor for the central LNR when more than 0.12 (OR _{adjusted 1} = 1.099, 95% CI 1.011-1.194, P₁ = 0.027; OR _{adjusted 2} = 1.177, 95% CI 1.003-1.381, P₂ = 0.045), for the lateral LNR more than 0.05 (P₂ = 0.283).

Conclusions

Obesity was associated with poor prognoses with PTC respecting LNs. Surgeons should be extreme caution when performing central neck dissection in obese patients.

The relationship between lipotoxicity and risk of extrathyroidal extension in papillary thyroid microcarcinoma

OBJECTIVE

To explore the relationship between triglyceride (TG) levels and aggressive pathological characteristics in papillary thyroid microcarcinoma (PTMC) patients, especially the relationship between TG, BMI, age, and extrathyroidal extension (ETE).

METHODS

A retrospective analysis of 9663 patients with PTMC in a single center from 2010 to 2017 was included in this study. Binary logistic regression was used to analyze the relationship between serum TG and aggressive pathological characteristics of PTMC in different genders. Further analyzing the risk of high TG in different ages and BMI groups.

RESULTS

Even after adjustment for confounding factors, high TG is still a risk factor for ETE in women with PTMC, but not a risk factor for men. Compared with the group with lower than 0.90 mmol/L, when the TG level is higher than 1.93 mmol/L, the risk of ETE in women increased by about 1.35-fold. The remaining two variables (BMI, age) as risk factors for ETE are analyzed. In the normal BMI group, high TG is still a risk factor for ETE. The risk of ETE in women more than 55 years old is significantly increased by 1.96-fold (1.34-fold in less than 55 years).

CONCLUSION

High TG in women is positively correlated with the risk of ETE in PTMC. PTMC with high TG in elderly women (more than 55 years) has a higher risk of ETE. TG is a potential serological index for predicting the risk of ETE in women with normal BMI.

A meta-analysis of the influence of body mass index on the clinicopathologic progression of papillary thyroid carcinoma

BACKGROUND

Papillary thyroid carcinoma (PTC) incidence has been increasing worldwide. Obesity, that is, having a high body mass index, is associated with the incidence of several cancers including colon, breast, esophageal, and kidney cancer. However, the association between obesity and the clinical features of PTC is still unknown. This study aimed to determine the impact of obesity on the clinical features of PTC.

METHOD

A database search was conducted for articles published up to 2020 on obesity and clinical features of PTC. Data were extracted from articles that met the meta-analysis inclusion criteria.

RESULTS

A total of 11 retrospective cohorts and 11,729 patients were included. Obesity was associated with the following variables in PTC patients: older age (difference in means = 1.95, 95% confidence interval [CI] 0.16-3.74, P = .03), male sex (odds ratio [OR] = 3.13, 95%CI 2.24-4.38, P < .00001), tumor size ≥1 cm (OR = 1.34, 95%CI 1.11-1.61, P < .002), multifocality (OR = 1.54, 95%CI 1.27-1.88, P < .0001), extrathyroidal extension (OR = 1.78, 95%CI 1.22-2.59, P = .003) and advanced tumor, node, metastasis stage (OR = 1.68, 95%CI 1.44-1.96, P < .00001). Preoperative serum thyroid-stimulating hormone level (difference in means  = 0.09, 95%CI 0.35-0.52, P = .70), Vascular invasion (OR = 0.84, 95%CI 0.56-1.26, P = .41), lymph node metastasis (OR = 1.07, 95%CI 0.87-1.32, P = .50), distant metastasis (OR = 1.14, 95%CI 0.64-2.04, P = .66), and recurrence (OR = 1.45, 95%CI 0.97-2.15, P = .07) were not associated with obesity.

CONCLUSION

Obesity was associated with several poor clinicopathologic prognostic features: older age, male gender, tumor size ≥1 cm, extrathyroidal extension, multifocality, and advanced tumor/node/metastasis stage. However, thyroid-stimulating hormone level, vascular invasion, lymph node metastasis, distant metastasis, and recurrence were not associated with obesity in PTC.

Global burden of thyroid cancer and its attributable risk factors in 204 countries and territories from 1990 to 2019

Background

To investigate the burden of thyroid cancer and its attributable risk factors in 204 countries and territories during 30 years.

Methods

We extracted data from the Global Burden of Disease (GBD) 2019 database, including incidence, mortality, disability‐adjusted life‐years (DALYs), and the attributable risk factors of thyroid cancer from 1990 to 2019. Estimated annual percentage changes (EAPC) were calculated to assess the changes in age‐standardized incidence rate (ASIR), age‐standardized mortality rate (ASMR), and age‐standardized DALYs rate (ASDR). We also examined the associations between cancer burden and the sociodemographic index (SDI).

Results

The global new cases, death, and DALYs of thyroid cancer in 2019 were 233 847 (95% UI: 211 637–252 807), 45 576 (95% UI: 41 290‐48 775), and 1 231 841 (95% UI: 1 113 585–1 327 064), respectively. From 1990 to 2019, the ASIR of thyroid cancer showed an upward trend (EAPC = 1.25), but ASMR (EAPC = −0.15) and ASDR (EAPC = −0.14) decreased. The burden of thyroid cancer varied at regional and national levels, but the association between ASIR and SDI was positive. We found that the burden of thyroid cancer was mainly concentrated in females and that the age of onset tended to be younger. The proportion of DALYs from thyroid cancer attributable to high body‐mass index was higher in high SDI regions, especially in males.

Conclusions

The global incidence of thyroid cancer has continued to increase in the past three decades. The high body‐mass index as an important risk factor for thyroid cancer deserves greater attention, especially in high SDI regions.

Presence of risk factors for thyroid cancer does not improve the performance of ultrasound screening for thyroid nodules in patients with obesity

PURPOSE

It has been suggested, on a theoretical basis, that ultrasound screening of thyroid nodules in obese patients with additional risk factors (family history, chronic autoimmune thyroiditis or high thyrotropin) might be cost-effective for the early detection and treatment of thyroid cancer. The present study evaluates if this approach can be validated in a real clinical setting.

METHODS

Patients with obesity who attended hospital-based clinics were evaluated for risk factors of thyroid cancer and ultrasound screened for thyroid nodularity. Detected nodules were evaluated according to current guidelines.

RESULTS

A total of 429 patients were evaluated (70.2% women, mean age 49.1 ± 11.0, mean body mass index 42.6 ± 5.8 kg/m² ). Risk factors were present in 129 (30.1%) patients. Thyroid nodules with indication for fine-needle aspiration biopsy were detected in 69 (16.1%). We did not find differences in the risk of harbouring thyroid nodules according to the presence of risk factors (no risk factors 16.6%, risk factors 14.1%, P = .64). No single risk factor conferred an increased risk for thyroid nodules During the screening procedure, four cases of thyroid cancer were detected, none of them with the evaluated risk factors.

CONCLUSION

The presence of known risk factors for thyroid cancer does not improve the performance of a US screening strategy aimed at the detection of thyroid nodules in obese patients. According to current guidelines, screening for thyroid nodules in obese patients is not recommended regardless of the presence of thyroid cancer risk factors.

Association of BMI with Clinicopathological Features of Papillary Thyroid Cancer: A Systematic Review and Meta-Analysis

BACKGROUND

Papillary thyroid cancer (PTC) is the most common subtype of thyroid cancer. The incidence of PTC is rising in tandem with an obesity epidemic. Associations have been demonstrated between increased body mass index (BMI) and worse oncological outcomes in a number of malignancies. However, research on this topic in PTC to date has been inconsistent, often due to limited data. This study aimed to measure the association between BMI and potentially adverse clinicopathological features of PTC.

METHODS

A meta-analysis of studies reporting outcomes after surgical treatment of PTC was performed. PubMed, Embase and the Cochrane Library were searched systematically to identify studies which provided data on BMI and clinicopathologic features of PTC. Relevant data were extracted and synthesis performed using adjusted odds ratios where available and crude values when not. Data were analysed by inverse variance using random and fixed effects models.

RESULTS

Data on 35,237 patients from 15 studies met the criteria for inclusion. Obesity was associated with larger tumour size (MD = 0.17 cm [0.05, 0.29]), increased rates of multifocality (OR = 1.41 [1.16, 1.70]), extrathyroidal extension (OR = 1.70 [1.39, 2.07]) and nodal spread (OR = 1.18 [1.07, 1.30]). Associations were more pronounced as BMI increased. There was no association between BMI and bilaterality, vascular invasion or metastatic spread.

CONCLUSION

Increased BMI is significantly associated with multiple potentially adverse features of PTC. The effect on long-term oncological outcomes requires further evaluation.

The global burden of thyroid cancer and its attributable risk factor in 195 countries and territories: A systematic analysis for the Global Burden of Disease Study

Background

Thyroid cancer is a growing threat to human health. Few studies have explored trends of thyroid cancer and relationships with social development factors. In this study, we explored the trend and relationship based on GBD.

Methods

By using GBD study, we obtained detailed data of thyroid cancer. Incidence, mortality and DALY were used to assess epidemiological characteristics. ASR and EAPC were used to estimate the trend.

Results

Globally, the incidence significantly increased from 1990 to 2017, especially in high‐income regions. Males and middle SDI region demonstrated a higher increase of age‐standardized incidence rates. Unlike incidence trend, mortality trend showed a minor increase, and even showed a decreasing trend in some regions such as Eastern Sub‐Saharan Africa. Additionally, the DALY trend also demonstrated a slightly increase with an EAPC of 0.77 (95% CI 0.73–0.81). More significant increase of DALY was found in males, middle SDI region and high‐income Asia Pacific. The incidence of thyroid cancer peaked in middle‐aged people, while the mortality and DALY peaked in elder‐aged. Moreover, the proportion of thyroid cancer deaths contributable to high BMI was highest in developed countries and middle‐aged people.

Conclusions

Thyroid cancer is a public health problem worldwide. Over‐diagnosis might be partly responsible for its rising trend. It remains us to revise the guidelines to avoid unnecessary burdens. Moreover, we should pay attention to the risk factors of thyroid cancer. More targeted measures should be formulated to improve potential environmental and lifestyle‐related factors which might contribute to rising trend of thyroid cancer.

Impact of Overweight and Obesity on US Papillary Thyroid Cancer Incidence Trends (1995-2015)

Background

Since the early 1980s, papillary thyroid cancer (PTC) incidence rates and the prevalence of obesity, a risk factor for PTC, have increased substantially in the United States. We estimated the proportion of PTC incidence in the United States attributable to overweight and obesity during 1995–2015.

Methods

National Institutes of Health-AARP Diet and Health Study cohort data (n = 457 331 participants, 50–71 years and cancer-free at baseline) were used to estimate multivariable-adjusted hazard ratios (HRs) for PTC across body mass index categories. Population attributable fractions (PAFs) were calculated using estimated hazard ratios and annual overweight and obesity prevalence estimates from the National Health Interview Survey. PAF estimates were combined with Surveillance, Epidemiology, and End Results-13 data to calculate annual percent changes in PTC incidence rates attributable (and unrelated) to overweight and obesity.

Results

Overweight (25.0–29.0 kg/m²) and obesity (≥30.0 kg/m²) were associated with 1.26-fold (95% confidence interval [CI] = 1.05- to 1.52-fold) and 1.30-fold (95% CI = 1.05- to 1.62-fold) increased risks of PTC, respectively, and nearly threefold (HR = 2.93, 95% CI = 1.25 to 6.87) and greater than fivefold (HR = 5.42, 95% CI = 2.24 to 13.1) increased risks of large (>4 cm) PTCs compared with normal weight (18.5–24.9 kg/m²). During 1995–2015, PAF estimates for overweight and obesity increased from 11.4% to 16.2% for all PTCs and from 51.4% to 63.2% for large PTCs. Overweight or obesity accounted for 13.6% and 57.8% of the annual percent changes in total (5.9%/y) and large (4.5%/y) PTC incidence rates, respectively, during 1995–2015.

Conclusions

Overweight and obesity may have contributed importantly to the rapid rise in PTC incidence during 1995–2015. By 2015, we estimate that one of every six PTCs diagnosed among adults 60 years or older, including nearly two-thirds of large PTCs, were attributable to overweight and obesity.

Obesity and Overweight Are Associated with Minimal Extrathyroidal Extension, Multifocality and Bilaterality of Papillary Thyroid Cancer

Epidemiological studies have shown a strong association between high body mass index (BMI) and papillary thyroid cancer (PTC). We assessed the clinical and histopathological features of PTC in patients with a higher BMI and compared them to analogous parameters in PTC patients with a normal BMI. We retrospectively analyzed 5021 medical records of patients admitted and surgically treated for thyroid tumors in one center between 2008 and 2018. Finally, we extracted data from 523 adult patients with PTC and stratified patients into two groups according to BMI: Group 1 with BMI < 25 kg/m² and Group 2 with BMI ≥ 25 kg/m². Data stratification was performed to estimate the association of overweight and obesity with clinical and histopathological features of PTC in both univariable and multivariable binary logistic regression analyses. Overall, compared to patients with a normal BMI, overweight and obese patients had a greater risk of minimal extrathyroidal extension (minimal ETE), multifocality and bilaterality of PTC (p < 0.001 for all). Analysis did not show that BMI was significantly associated with the more advanced tumor-node-metastasis (TNM) stage (p = 0.894). Obesity and overweight were significantly associated with higher aggressiveness of PTC. When considering various management options for PTC patients, these findings regarding overweight and obesity should be taken into consideration during the decision-making process.

Influence of body mass index at diagnosis on outcome of thyroid cancer in children and adolescents

PURPOSE

To systemically examine the relationship between body mass index, the extent of thyroid cancer and metastatic burden at diagnosis, and overall outcomes in children and adolescents with thyroid cancer.

METHODS

A retrospective series of children and adolescents with differentiated thyroid cancer who underwent total thyroidectomy and ¹³¹I therapy was analyzed. Body mass index (BMI) at the time of surgery was assessed. The Chinese age- and sex-specific BMI percentile criteria for screening overweight and obesity in children and adolescents were used to define the overweight and obesity among patients. The relationship between BMI and clinicopathological features and clinical outcomes of the disease was evaluated by logistic regression modeling, incorporating the eighth edition of the American Joint Committee on Cancer TNM staging system and the 2015 American Thyroid Association guidelines.

RESULTS

This study included 181 children and adolescents with differentiated thyroid cancer (82.9% females, median age 17 years). The mean BMI was 21.0 ± 3.9 kg/m²; 77.9% of the patients (N = 141) were normal weight, 13.2% (N = 24) were overweight, and 8.8% (N = 16) were obese. No positive associations were noted between BMI and T, N, or M stage on logistic regression analyses. The absence of an association was also demonstrated on analysis by BMI categories. After a median follow-up of 51 months, 114 children and adolescents (63.0%) had achieved excellent response to therapy. No associations were noted for persistent/recurrent disease among BMI groups.

CONCLUSION

Our study highlights the absence of increased disease burden at the time of thyroid cancer diagnosis in pediatric patients with high BMI along with the same prognosis compared with normal-weight pediatric patients.

Association Between Aggressive Clinicopathologic Features of Papillary Thyroid Carcinoma and Body Mass Index: A Systematic Review and Meta-Analysis

BACKGROUND

The association between adiposity and papillary thyroid carcinoma (PTC) has been reported in several studies, but its association with aggressive clinicopathologic features is not well-recognized. Our aim is to systematically review the literature to identify whether adiposity, expressed through Body Mass Index (BMI), is related to aggressive clinicopathologic features such as tumor-node-metastasis (TNM) stage, extrathyroidal extension (ETE), lymph node (LN) metastasis and multifocality in patients with PTC.

METHODS

A systematic search for articles was performed using the PubMed, EBSCO, and Cochrane Library for all articles published in English until December 2020. Specific keywords such as "papillary thyroid carcinoma", "Body Mass Index", "clinicopathologic features" were used in the search strategy. Two independent reviewers screened all retrieved articles based on predefined inclusion and exclusion criteria. Meta-analysis was performed in the studies that reported crude and adjusted odds ratios (OR). The methodological quality was assessed using the Newcastle-Ottawa Scale.

RESULTS

A total of 11 retrospective cohort studies involving 26,196 participants included. Our findings showed that elevated BMI was significantly associated with ETE in both overweight (OR 1.26, 95% CI: 1.09-1.44) and obesity group (OR 1.45, 95% CI:1.26-1.64). Elevated BMI was also significantly associated with multifocality in overweight patients (OR 1.17, 95% CI:1.10-1.24) and obese patients (OR 1.45, 95% CI:1.29-1.62). Also, obesity was significantly associated with increased tumor size (OR 1.77, 95% CI:1.52-2.03) and with LN metastasis (OR 1.28, 95% CI: 1.12-1.44), whereas being overweight was significantly associated with advanced TNM stage (OR 1.55, 95% CI:1.27-1.83).

CONCLUSION

Our results provide strong evidence for the association between higher BMI and ETE, multifocality, and tumor size. Further studies with a larger number of participants are required to elucidate further the association of increased BMI with advanced TNM stage and LN metastasis.

Progression of incidence and estimate of net survival from papillary thyroid cancers diagnosed between 2008 and 2016 in France

BACKGROUND

After several decades of increasing incidence of papillary thyroid cancer (PTC), a change in this trend has been recently observed, particularly in the United States. This is attributed to the impact of new guidelines for the management of thyroid disease. The objective of this study was to describe the recent situation in France in terms of incidence and survival, taking account of tumor size.

METHODS

Data from the FRANCIM network cancer registries, covering around 25% of the French metropolitan population, were analyzed. Distribution according to tumor size was determined in terms of frequency, trends in incidence and spatial distribution for the period 2008-2016. Analysis of net survival considered gender, age and tumor size.

RESULTS

Cancers of size≤5mm were predominant in patients diagnosed between 55 and 74 years of age. Incidence of≤5mm tumors in women and of 5-10mm tumors in men began declining in the early 2010s. Incidence of 10-20mm and 20-40mm tumors in men increased significantly throughout the period 2008-2016. For both men and women, the incidence of the largest tumors (>40mm) also increased, but not significantly. The spatial distribution of incidence showed great heterogeneity. Net survival was generally high, although decreasing with age and tumor size.

CONCLUSION

The recent epidemiological situation in France is consistent with the hypothesis of recent progress in medical management of thyroid pathologies. Variations in incidence should be monitored for both small (<10mm) and larger tumors, and notably>40mm tumors. Net survival is generally high, although decreasing with age and tumor size.

Can thyroidectomy be considered safe in obese patients? A retrospective cohort study

BACKGROUND

Obesity is a growing public health concern in most western countries. More and more patients with high body mass index (BMI) are undergoing surgical procedures of all kinds and, in this context, obese patients are undergoing thyroid surgery more than ever before. The aim of the present study was to evaluate whether thyroidectomy can be considered safe in obese patients.

METHODS

Patients undergoing thyroidectomy in our Unit between January 2014 and December 2018 were retrospectively analysed. Patients were divided into two groups: those with BMI < 30 kg/m² were included in Group A, while those with BMI ≥ 30 kg/m² in Group B. Univariate analysis was performed to compare these two groups. Moreover, multivariate analyses were performed to evaluate whether the BMI value (considered in this case as a continuous variable) had a significant role in the development of each individual postoperative complication.

RESULTS

A total of 813 patients were included in this study: 31 (3.81%) were underweight, 361 (44.40%) normal-weight, 286 (35.18%) overweight, 94 (11.57%) obese and 41 (5.04%) morbidly obese. Six hundred and seventy-eight patients were included in Group A and 135 in Group B. At univariate analysis, the comparison between the two groups, in terms of operative time and thyroid weight resulted in statistically significant results (P = 0.001, P = 0.008; respectively). These features were significantly higher in Group B than in Group A. About postoperative stay and complications, no statistically significant difference was found between the two groups. At multivariate analyses, only the development of cervical haematoma was statistically significantly correlated to the BMI value. Patients with high BMI had a lower risk of cervical haematoma (P = 0.045, OR 0.797, 95% CI 0.638-0.995).

CONCLUSIONS

This study showed that obesity, in the field of thyroid surgery, is not associated with any increase of postoperative complications. Thus, it is possible to conclude that thyroidectomy can be performed safely in obese patients. Our result about operative times had no clinical significance.

Obesity and the prevention of thyroid cancer: Impact of body mass index and weight change on developing thyroid cancer - Pooled results of 24 million cohorts

BACKGROUND

Body weight may be a modifiable risk factor predisposing to different cancers. To establish a potential impact of weight change on thyroid cancer risk, we conducted a meta-analysis to evaluate the effect of body mass index (BMI) and weight change over time as a risk of developing thyroid cancer (TC).

METHODS

A systematic search was performed up to February 25, 2020. Pooled relative risk (RR) were estimated using fixed and random models. Heterogeneity between articles was examined using Q-test and I² index. Evaluation of publication bias was conducted with Egger's regression test.

RESULTS

A total of 31 studies including 24,489,477 cohorts were eligible. Pooled analysis revealed that normal and underweight cohorts were associated with a decreased risk of TC (RR = 0.68, 95%CI = 0.65-0.71, p < 0.001) and (RR = 0.92, 95%CI = 0.91-0.93, p < 0.001), respectively. In contrast, overweight and obese cohorts were more likely to develop TC (RR = 1.26, 95%CI = 1.24-1.28, p < 0.001 and RR = 1.50, 95%CI = 1.45-1.55, p < 0.001, respectively). Obesity was associated with higher risk of developing TC among women (RR = 1.29, 95%CI = 1.14-1.46, p < 0.001), but not men (RR = 1.25, 95%CI = 0.97-1.62, p = 0.08). Furthermore, weight gain increased the risk of developing TC (RR = 1.18, 95%CI = 1.14-1.22, p < 0.001), while weight loss decreased the risk (RR = 0.89, 95%CI = 0.85-0.93, p < 0.001). Results showed similar trends of weight change effect in both males and females.

CONCLUSIONS

Obesity is associated with higher risk of developing TC in women. However, maintaining a healthy weight is associated with reduced risk of TC in both women and men. Shifting our practice to include weight control strategies will help lead to cancer prevention.

Preoperative Factors Associated with Extrathyroidal Extension in Papillary Thyroid Cancer

OBJECTIVE

Extrathyroidal extension may not be accurately recognized during thyroidectomy and can increase the risk of positive margins and even recurrence. This study aimed to investigate the preoperative factors associated with extrathyroidal extension.

METHODS

We analyzed 887 patients with papillary thyroid cancer (PTC) who underwent surgery in the period of 2005-2017. Binary logistic regression analyses and generalized additive models were used to identify associations.

RESULTS

Minimal extrathyroidal extension was present in 233 (26%) patients and advanced extrathyroidal extension was found in 60 (7%) patients. Age, BMI, and tumor size were independent predictors of all or advanced extrathyroidal extension. Among the 493 patients whose BRAF mutation status was available, age (OR = 1.025), BMI (OR = 1.091), tumor size (OR = 1.544), and BRAF V600E mutation (OR = 2.311) were independently associated with extrathyroidal extension.

CONCLUSIONS

Older age, a greater BMI, a larger tumor size, and presence of the BRAF mutation were predictive of extrathyroidal extension. These factors should be taken into consideration in decision-making before surgery is performed.

Influence of body mass index on the clinicopathological features of 13,995 papillary thyroid tumors

PURPOSE

This retrospective study aimed to assess the association between obesity, gender, and specific clinicopathological features in patients with papillary thyroid cancer (PTC) and whether diagnostic ultrasonography (US) is adversely affected by obesity in these patients.

MATERIALS AND METHODS

This study retrospectively analyzed 13,995 adult patients with PTC from a single medical center in China. Data stratification was performed to assess the association of obesity with US features and aggressive clinicopathological features in different models according to the World Health Organization Body Mass Index (WHO-BMI) and Chinese BMI classification (CN-BMI). The odds ratio (OR) of malignant US features and aggressive clinicopathological features was calculated from binary logistic regression models.

RESULTS

The BMI, obesity ratio, malignant US features, and aggressive pathological characteristics of males were significantly higher than those of females. After adjusting for confounding factors, the association of obesity with malignant US features and aggressive pathological characteristics was found to be sex-dependent. Next, obesity (WHO-BMI) was found to have an "interfering effect" on the US assessment of PTC (OR = 0.754, 95% CI 0.609-0.932, P = 0.009) in women. Among both sexes, obesity (WHO-BMI) increased the risk of tumor size (OR_male = 1.539 and OR_female = 1.521) and multifocality (OR_male = 1.659 and OR_female = 1.449). However, obesity did not increase the risk of capsular invasion or tumor staging in males. The above results are consistent with the CN-BMI. In addition, age was found to have an "interfering effect" on the US evaluation of malignant nodules in both sexes.

CONCLUSION

The results of our study confirm that higher BMI is significantly associated with aggressive clinicopathological features of PTC. Gender differences were present with obesity ratios and aggressive clinicopathological features being significantly higher in men.

Does Obesity Cause Thyroid Cancer? A Mendelian Randomization Study

BACKGROUND

The incidence of thyroid cancer is rising, and relatively little is known about modifiable risk factors for the condition. Observational studies have suggested a link between adiposity and thyroid cancer; however, these are subject to confounding and reverse causality. Here, we used data from the UK Biobank and Mendelian randomization approaches to investigate whether adiposity causes benign nodular thyroid disease and differentiated thyroid cancer.

METHODS

We analyzed data from 379 708 unrelated participants of European ancestry in the UK Biobank and identified 1812 participants with benign nodular thyroid disease and 425 with differentiated thyroid carcinoma. We tested observational associations with measures of adiposity and type 2 diabetes mellitus. One and 2-sample Mendelian randomization approaches were used to investigate causal relationships.

RESULTS

Observationally, there were positive associations between higher body mass index (odds ratio [OR], 1.15; 95% confidence interval [CI], 1.08-1.22), higher waist-hip ratio (OR, 1.16; 95% CI, 1.09-1.23), and benign nodular thyroid disease, but not thyroid cancer. Mendelian randomization did not support a causal link for obesity with benign nodular thyroid disease or thyroid cancer, although it did provide some evidence that individuals in the highest quartile for genetic liability of type 2 diabetes had higher odds of thyroid cancer than those in the lowest quartile (OR, 1.45; CI, 1.11-1.90).

CONCLUSIONS

Contrary to the findings of observational studies, our results do not confirm a causal role for obesity in benign nodular thyroid disease or thyroid cancer. They do, however, suggest a link between type 2 diabetes and thyroid cancer.

Thyroid surgery in obese patients: A review of the literature

The incidence of obesity in the general population has tripled in the past four decades. The number of bariatric surgeries performed annually has quadrupled in the past ten years due to this obesity epidemic. Concomitantly, the number of patients who are obese or who have undergone bariatric surgery and have become candidates for thyroid surgery has also increased considerably. Among patients undergoing thyroidectomy in the French population, the proportion of obese patients currently represents 10 to 20%. In addition, the frequency of benign and malignant thyroid pathologies seems to be increased by obesity, with a Hazard Ratio of around 1.8 for thyroid cancers in obese women. While obesity does not seem to influence the specific post-operative morbidity of thyroidectomy, a history of malabsorptive bariatric surgery should encourage the greatest caution in patients who need to undergo thyroid surgery since it is associated with a significant risk of severe hypocalcemia (>60% in some studies) requiring intravenous calcium supplementation in about 20% of cases. In the latter situation, peri-operative vitamin D-calcium supplementation is essential. In addition, the replacement dose of Levothyroxine (T4) intended for replacement must also be adapted in obese patients, calculated not from the actual weight but from the ideal weight. The objective of this review is to discuss the influence of obesity on the evolution of nodular and neoplastic thyroid pathologies, on the morbidity of thyroid surgery as well as on post-operative drug treatments. The impact of bariatric surgery on these different aspects is also discussed.

The role of metabolic setting in predicting the risk of early tumour relapse of differentiated thyroid cancer (DTC)

BACKGROUND

The role of insulin resistance and adipocytokines in determining the phenotype and recurrence of differentiated thyroid cancer (DTC) is still unknown. In a previous study, we observed an association between metabolic setting, circulating adipocytokines and thyroid cancer phenotype. The aim of this study was to evaluate the clinical follow-up of patients with DTC and the predictive role of metabolic setting on the risk of tumour relapse.

METHODS

Between September 2016 and January 2017, 57 patients were admitted to our institution to undergo total thyroidectomy because of suspected DTC. Thirty patients with post-surgical histological diagnosis of DTC were included in the study. Each subject underwent pre-surgical analysis of anthropometric parameters, thyroid function and autoimmunity, glucose metabolism, insulin resistance (HOMA-IR) and levels of unacylated and acylated ghrelin, obestatin, leptin and adiponectin. Tumour recurrence at 1 and 3 years from diagnosis was assessed.

RESULTS

Most patients were females (21F, 9M) with a median age at diagnosis of 50.0 (41.0-58.8). At baseline, overweight was found in 7 patients and obesity in 6 cases. Insulin resistance was detected in 14 patients. Overall, 17 patients (56.7%) underwent radioiodine treatment after surgery. During the follow-up, we observed a persistent biochemical disease in one patient whereas tumour relapse was found in six patients at 1 year from diagnosis (lymph node metastases) and in one patient at 3 years from diagnosis (lung metastases). Independently from age, sex, stage of disease and the presence of lymph node metastasis at diagnosis, higher BMI, leptin and insulin levels as well as HOMA-IR were associated with a higher risk of tumour relapse (p < 0.05 for all).

CONCLUSIONS

Our results highlight a possible role for BMI, leptin and insulin resistance as predictors of early DTC relapse.

Potential Impact of BMI on the Aggressiveness of Presentation and Clinical Outcome of Differentiated Thyroid Cancer

BACKGROUND

Obesity is a risk factor for several cancers, including differentiated thyroid cancer (DTC). Moreover, it has also been investigated as a potential risk factor for aggressiveness of DTC, but the data gathered so far are conflicting. The aim of our study was to evaluate the relationship between body mass index (BMI), aggressiveness of DTC at diagnosis, and clinical outcome.

METHODS

We evaluated 1058 consecutive DTC patients treated with total thyroidectomy and enrolled at the time of first radioactive iodine (131I) treatment. Patients were divided into 4 groups based on their BMI: underweight (< 18.5 kg/m2), normal weight (18.5-24.9 kg/m2), overweight (25-29.9 kg/m2), and obese (≥ 30 kg/m2). Histological aggressiveness of DTC at the time of diagnosis and clinical outcome according to 2015 American Thyroid Association (ATA) guidelines were evaluated.

RESULTS

No differences in histological features, ATA risk of recurrence, activity of 131I administered and prevalence of 131I avid metastatic disease after first131I treatment, have been demonstrated among the groups. Furthermore, at the end of follow up (median = 5.7 years), no differences were evident in the number of further treatments performed as well as in the clinical response.

CONCLUSIONS

In our study group of Caucasian subjects, we could not demonstrate any association between BMI and aggressiveness of DTC, neither at the time of diagnosis nor during follow-up. These data indicate that postsurgical assessment and therapeutic attitude for treatment and follow-up of DTC should be based on the class of risk applied to the general population, with no concern for BMI.

Adolescent overweight and obesity and the risk of papillary thyroid cancer in adulthood: a large-scale case-control study

This study aimed to investigate the association between adolescent overweight and obesity and PTC risk in adulthood. We conducted a case-control study in the Republic of Korea with 1,549 PTC patients and 15,490 controls individually matched for age and sex. We estimated body mass index (BMI) at age 18 years from self-reported weight at this age. Compared with BMI < 23.0 at age 18 years, BMI ≥ 25.0 at age 18 years was associated with higher PTC risk (odds ratio [OR] = 4.31, 95% confidence interval [CI]: 3.57, 5.22). The association between BMI ≥ 25.0 at age 18 years and PTC risk was stronger among men (OR = 6.65, 95% CI: 4.78, 9.27) than among women (OR = 3.49, 95% CI: 2.74, 4.43), and stronger among individuals with current BMI ≥ 25.0 (OR = 8.21, 95% CI: 6.34, 10.62) than among those with current BMI < 25.0 (OR = 2.21, 95% CI: 1.49, 3.27). Among PTC patients, BMI ≥ 25.0 at age 18 years was associated with extra-thyroidal extension and T stage ≥2, but not with N stage ≥1 or BRAFV600E mutation. Adolescent overweight and obesity was associated with higher risk of PTC in adulthood. Our results emphasise the importance of weight management in adolescence to decrease the PTC risk.

Association between subjective symptoms and obesity and postoperative recurrence in differentiated thyroid cancer: a matched-pair analysis

Several patients with thyroid cancer experience symptom distress after diagnosis and surgery. Data on the association between symptomatology and disease recurrence are limited. A retrospective review of a prospectively maintained database was performed, and 57 patients who had recurrence after operation of differentiated thyroid cancer were identified. Controlling for age, sex, surgery, and tumour stage, 114 patients without recurrent disease were selected by case-control matching. Subjective symptoms at follow-up visits were extracted from medical records and classified into three symptom clusters: pharyngolaryngeal, psychoneurological, and gastrointestinal. Compared to the control group, patients with recurrence had higher symptom totals in the pharyngolaryngeal (P < 0.001) and psychoneurological clusters (P = 0.005). Symptom score >3 yielded a sensitivity of 61.4% and a specificity of 80.7% to predict recurrence. Multivariate Cox regression analysis revealed that high symptom score (hazard ratio [HR] = 4.184), family history of thyroid cancer (HR = 2.463), and obesity (HR = 1.981) were independently associated with disease recurrence. Taken together, the likelihood of postoperative recurrence seemed to increase with high self-perceived symptom burden, family history, and obesity in patients with thyroid cancer. The results could be applied to the recurrence surveillance and symptomatic management of thyroid cancer post-operation.

Thyroid nodules: diagnostic evaluation based on thyroid cancer risk assessment

Thyroid nodules are extremely common and can be detected by sensitive imaging in more than 60% of the general population. They are often identified in patients without symptoms who are undergoing evaluation for other medical complaints. Indiscriminate evaluation of thyroid nodules with thyroid biopsy could cause a harmful epidemic of diagnoses of thyroid cancer, but inadequate selection of thyroid nodules for biopsy can lead to missed diagnoses of clinically relevant thyroid cancer. Recent clinical guidelines advocate a more conservative approach in the evaluation of thyroid nodules based on risk assessment for thyroid cancer, as determined by clinical and ultrasound features to guide the need for biopsy. Moreover, newer evidence suggests that for patients with indeterminate thyroid biopsy results, a combined assessment including the initial ultrasound risk stratification or other ancillary testing (molecular markers, second opinion on thyroid cytology) can further clarify the risk of thyroid cancer and the management strategies. This review summarizes the clinical importance of adequate evaluation of thyroid nodules, focuses on the clinical evidence for diagnostic tests that can clarify the risk of thyroid cancer, and highlights the importance of considering the patient's values and preferences when deciding on management strategies in the setting of uncertainty about the risk of thyroid cancer.

Geographic influences in the global rise of thyroid cancer

The incidence of thyroid cancer is on the rise, and this disease is projected to become the fourth leading type of cancer across the globe. From 1990 to 2013, the global age-standardized incidence rate of thyroid cancer increased by 20%. This global rise in incidence has been attributed to several factors, including increased detection of early tumours, the elevated prevalence of modifiable individual risk factors (for example, obesity) and increased exposure to environmental risk factors (for example, iodine levels). In this Review, we explore proven and novel hypotheses for how modifiable risk factors and environmental exposures might be driving the worldwide increase in the incidence of thyroid cancer. Although overscreening and the increased diagnosis of possibly clinically insignificant disease might have a role in certain parts of the world, other areas could be experiencing a true increase in incidence due to elevated exposure risks. In the current era of personalized medicine, national and international registry data should be applied to identify populations who are at increased risk for the development of thyroid cancer.

Association of obesity with the clinicopathological features of thyroid cancer in a large, operative population: A retrospective case-control study

We aimed to investigate the association between excess body mass index (BMI) and papillary thyroid cancer (PTC) in an operative population, and the impact of higher BMI on clinicopathological aggressiveness of PTC.Charts of 10,844 consecutive patients with thyroid nodules undergoing partial or total thyroidectomy between 1993 and 2015 were reviewed. Patients diagnosed with PTC were stratified in 4 groups: BMI < 18.5 (underweight), 18.5 ≤ BMI < 24 (normal-weight), 24 ≤ BMI < 28 (overweight) and BMI ≥ 28(obese). The impacts of high BMI on prevalence and clinicopathological parameters of PTC were retrospectively analyzed in both univariate and multivariate binary logistic regression analysis.For every 5-unit increase in body mass, the odds of risk-adjusted malignance increased by 36.6%. The individuals who were obese and overweight were associated with high risk of thyroid cancer [odds ratio (OR)= 1.982, P < .001; OR= 1.377, P < .001; respectively] compared to normal weight patients, and this positive association was found in both genders. Obesity was independent predictors for tumors larger than 1 cm (OR = 1.562, P < .001) and multifocality (OR = 1.616, P < .001). However, there was no difference in cervical lymph node (LN) metastasis among BMI groups. Crude analysis showed BMI was associated with advanced tumor-node-metastasis (TNM) stage (relative risk, approximately 1.23 per 5 BMI units, P < .001), but this association disappeared after adjusting for confounding factors.Obesity was significantly associated with the risk of PTC in a large, operative population. Higher BMI was significantly associated with larger tumor size and multifocal tumor.

Influence of Body Mass Index on the Clinicopathologic Features of Papillary Thyroid Carcinoma

BACKGROUND

Epidemiologic studies have demonstrated an increased risk for papillary thyroid carcinoma (PTC) with increasing body mass index (BMI). However, the relationships between excess weight and the behavior of PTC are inconsistent. The aim of this study was to evaluate the impact of excess weight on clinicopathologic features of PTC and on patient outcomes.

METHODS

Data from 417 patients with PTC who underwent total thyroidectomy with cervical lymph node dissection were retrospectively analyzed. On the basis of World Health Organization standardized categories of BMI, patients were divided into 4 groups: underweight, normal weight, overweight, and obese. Histopathologic tumor features, stage at diagnosis, and disease status were determined by chart review. Logistic regression models were used to define associations between BMI and clinicopathologic features of PTC. Cox proportional-hazards models were used to assess associations between BMI and locoregional recurrence.

RESULTS

Overweight (odds ratio [OR], 3.90; P = .040) and obesity (OR, 9.19; P = .012) were independent predictors of vascular invasion. Furthermore, obesity (OR, 6.14; P = .004) was an independent predictor of extrathyroidal invasion. During follow-up (median, 29 months; range, 5-87 months), 48 patients (11.5%) experienced locoregional recurrence. There were no significant differences in locoregional recurrence of PTC among BMI groups. When adjusted for other confounding factors, extrathyroidal invasion (OR, 8.35; P < .001), vascular invasion (OR, 3.57; P < .001), cervical lymph node metastasis (OR, 3.71; P = .009), and advanced tumor-node-metastasis stage (OR, 3.81; P < .001) were identified as independent factors for locoregional recurrence.

CONCLUSIONS

Higher BMI was associated with extrathyroidal invasion and vascular invasion in patients with PTC, which suggests that excess weight is associated with aggressive clinicopathologic features of PTC. But patients with higher BMI did not have an increased risk for developing postoperative complications and locoregional recurrence.

Metabolic Obesity Phenotypes and Thyroid Cancer Risk: A Cohort Study

BACKGROUND

No cohort studies have evaluated the effect of obesity on the incidence of thyroid cancer according to metabolic health status. Therefore, this study examined the association of body mass index (BMI) and metabolic health status with thyroid cancer risk.

METHODS

A cohort study was performed involving 255,051 metabolically healthy (MH) and metabolically unhealthy (MUH) adults free of thyroid cancer at baseline who were followed for a median of 5.3 years. A parametric proportional hazard model was used to estimate the adjusted hazard ratio (aHR) and confidence interval (CI).

RESULTS

During 1,402,426.3 person-years of follow-up, 2927 incident thyroid cancers were identified. Among men, the multivariable aHR for thyroid cancer comparing obesity, defined as a BMI ≥25 kg/m², with a BMI of 18.5-22.9 kg/m² was 1.47 [CI 1.12-1.93] in MH individuals, whereas the corresponding HR in MUH individuals was 1.26 [CI 1.03-1.53]. Among women, the corresponding HR in MH individuals was 1.05 [CI 0.80-1.36], whereas the corresponding HR in MUH individuals was 1.43 [CI 1.22-1.69]. Increasing quartiles of waist circumference were positively associated with risk of thyroid cancer in MUH men and women (p for trend <0.005) but not in MH individuals.

CONCLUSIONS

In both MH and MUH men, obesity was associated with an increased risk of incident thyroid cancer, indicating excessive adiposity per se as an independent risk factor for thyroid cancer. Conversely, women with MUH obesity but not MH obesity were found to have an increased risk of thyroid cancer, indicating that obesity with accompanying metabolic abnormalities may affect thyroid cancer risk in women.

Evolving Understanding of the Epidemiology of Thyroid Cancer

The incidence of thyroid cancer worldwide has increased significantly over the past 3 decades, due predominantly to an increase in papillary thyroid cancer. Although most of these cancers are small and localized, population-based studies have documented a significant increase in thyroid cancers of all sizes and stages, in addition to incidence-based mortality for papillary thyroid cancer. This suggests that the increasing incidence of thyroid cancer is due in large part to increasing surveillance and overdiagnosis, but that there also appears to be a true increase in new cases of thyroid cancer.

Weight change is significantly associated with risk of thyroid cancer: A nationwide population-based cohort study

Obesity is a risk factor for many cancers including breast, esophageal, colon, and thyroid cancer. We aimed to evaluate the association of thyroid cancer with body mass index (BMI), waist circumference (WC), and weight change. This nationwide population-based cohort study included 11,323,006 adults who joined the national health screening program. Weight change was defined as the difference between the weight of the subjects measured during the study period and the weight at the time of four years ago. For evaluating the association between the weight change and the risk of thyroid cancer, subjects without weight change for four years were defined as the reference group. Mean age was 50.1 ± 13.7 years and 44% were female. In total, 50,464 subjects (0.4%) had newly-diagnosed thyroid cancer. After multivariable analyses, the incidence of thyroid cancer increased significantly in subjects with larger WC as well as higher BMI (P < 0.001 and P < 0.001, respectively). In subjects who were lean and became obese, the incidence of thyroid cancers increased significantly (hazard ratio [HR] 1.15 [1.11-1.19]). In subjects who were obese and became lean, the incidence of thyroid cancers decreased significantly (HR 0.89 [0.86-0.93]). These results demonstrated that higher BMI and larger WC were significantly associated with an increased risk of thyroid cancer. Weight gain in lean subjects was associated with an increased risk of thyroid cancer, and weight reduction in subjects with obesity was associated with a decreased risk of thyroid cancer.

Relation between hysterectomy, oophorectomy and the risk of incident differentiated thyroid cancer: The E3N cohort

BACKGROUND

Thyroid cancers are threefold more frequent in women than in men. A role of reproductive or hormonal factors has been suggested but with contradictory results. We investigated potential associations between history of hysterectomy, with or without oophorectomy, and history of benign gynaecological disease (uterine fibroids, endometriosis) and the incidence of differentiated thyroid cancer, in a large French prospective cohort.

METHODS

A total of 89 340 women from the E3N cohort were followed up between 1990 and 2012. Gynaecological diseases treated by surgery were self-reported. Thyroid cancers were validated by histological reports. Time-dependent covariates included smoking status, BMI and history of benign thyroid disease. Cox proportional hazard models with age as timescale were used to estimate Hazard Ratios (HR) and 95% confidence intervals (CI).

RESULTS

A total of 412 cases of thyroid cancer were diagnosed during follow-up. A history of hysterectomy was associated with an increased risk of differentiated thyroid cancer (adjusted HR=2.05; 95%CI: 1.65-2.55). The association was not altered after further adjustment for reproductive factors. Endometriosis, uterine polyps, ovarian cysts and oophorectomy without hysterectomy were not associated with the risk of thyroid cancer. A history of fibroids was also significantly related to the risk of thyroid cancer over the follow-up period (adjusted HR=1.91; 95%CI: 1.50-2.44) and the increased risk persisted after adjustment for history of hysterectomy.

CONCLUSIONS

Women who had either a history of fibroids or hysterectomy had an increased risk of differentiated thyroid cancer. These findings suggest shared biological mechanisms between fibroids and thyroid cancer, which deserve to be further dissected.

The impact of BMI on clinical progress, response to treatment, and disease course in patients with differentiated thyroid cancer

Introduction

Obesity is a serious health problem worldwide, particularly in developed countries. It is a risk factor for many diseases, including thyroid cancer. The relationship between obesity and prognostic factors of thyroid cancer is unclear.

Aims

We sought to ascertain the relationship between body mass index (BMI) and clinicopathological features increasing the risk of poor clinical course, treatment response, and clinical outcome in patients with differentiated thyroid cancer (DTC).

Subjects & methods

The study included 1181 patients with DTC (88% women and 12% men) treated at a single center from 2000 to 2016. BMI before surgery and aggressive clinicopathological features, according to the American Thyroid Initial Risk stratification system, were analyzed. The relationship between BMI and initial risk, treatment response, and final status of the disease was evaluated, incorporating the revised 2015 American Thyroid Association guidelines and the 8^th edition of the American Joint Committee on Cancer/Tumor-Node-Metastasis (AJCC/TNM) staging system. Patients were stratified according to the World Health Organization classification of BMI. Statistical analysis was performed using univariate and multivariate logistic regression analysis.

Results

Median follow-up was 7.7 years (1–16 years). There were no significant associations between BMI and extrathyroidal extension (microscopic and gross), cervical lymph node metastasis, or distant metastasis in univariate and multivariate analyses. BMI did not affect initial risk, treatment response or disease outcome. Obesity was more prevalent in men (p = 0.035) and in patients ≥55 years old (p = 0.001). There was no statistically significant relationship between BMI and more advanced TNM stage in patients ≤55 years old (stage I vs. stage II) (p = 0.266) or in patients >55 years old (stage I–II vs. III–IV) (p = 0.877).

Conclusions

Obesity is not associated with more aggressive clinicopathological features of thyroid cancer. Obesity is not a risk factor for progression to more advanced stages of disease, nor is it a prognostic factor for poorer treatment response and clinical outcome.

Thyroid surgery and obesity: Cohort study of surgical outcomes and local specific complications

INTRODUCTION

Obesity is associated with numerous complications after elective general surgeries. The aim is to compare surgical outcomes and local specific complications in obese and non-obese patients after thyroid surgery.

METHODS

Retrospective study over a 3-year period at a North American academic institution. Outcome measures were operative time, estimated blood loss, hospital length of stay, and local specific complications (hypocalcemia, recurrent laryngeal nerve injury, wound hematoma, wound seroma, and chyle leakage).

RESULTS

A total of 469 patients were included (mean [SD] age, 50.11 [15.01] years; mean [SD] BMI, 30.5 [8.3] kg/m²; 207 [44.14%] obese). There was no difference in operative time (125.7 vs. 129.6, p = 0.52), estimated blood loss (16.88 vs. 14.56, p = 0.28), or hospital length of stay (0.95 vs. 0.95, p = 0.96). Overall, there was no difference in the rates of local specific complications between the two groups.

CONCLUSIONS

Obesity is not associated with adverse outcomes in patients undergoing thyroid surgery.

Early estimates of cancer incidence for 2015: Expanding to include estimates for white and black races

BACKGROUND

The National Cancer Institute's cancer incidence estimates through 2015 from the Surveillance, Epidemiology, and End Results (SEER) registries' November 2017 submission are released in April 2018.

METHODS

Early estimates (February 2017) of cancer incidence rates and trends from the SEER 18 registries for diagnoses in 2000 through 2015 were evaluated with a revised delay-adjustment model, which was used to adjust for the undercount of cases in the early release. For the first time, early estimates were produced for race (whites and blacks) along with estimates for new sites: the oral cavity and pharynx, leukemia, and myeloma.

RESULTS

Model validation comparing delay-adjusted rates and trends through 2014 and using 2016 submissions showed good agreement. Differences in trends through 2015 in comparison with those through 2014 were evident. The rate of female breast cancer rose significantly from 2004 to 2015 by 0.3% per year (annual percent change [APC] = 0.3%); the prior trend through 2014 (the same magnitude) was not yet significant. The female colon and rectum cancer trend for whites became flat after previously declining. Lung and bronchus cancer for whites showed a significant decline (APC for males = -2.3%, 2012-2015; APC for females = -0.7%, 2011-2015). Thyroid cancer for black females changed from a continuous rise to a flat final segment (APC = 1.6%, not significant, 2011-2015). Both kidney and renal pelvis cancer (APC = 1.5%, 2011-2015) and childhood cancers (APC = 0.5%, 2000-2015) for white males showed a significant rise in the final segments from previously flat trends. Kidney and renal pelvis cancer for black males showed a change from a significant rise to a flat trend.

CONCLUSIONS

The early release of SEER data continues to be useful as a preliminary estimate of the most current cancer incidence trends. Cancer 2018;124:2192-204. © 2018 American Cancer Society.

Association of Obesity and Thyroid Cancer at a Tertiary Care Hospital in Pakistan

Objective

Thyroid cancer (TC) is one of the most common endocrine malignancies with a rapidly increasing worldwide presence. In Pakistan, it is more prevalent in females than males and has an incidence rate of 2.1%. Obesity and excess body mass index (BMI) has been linked to several cancers and is thought to be a risk factor for TC. We aim to investigate the incidence of TC in our population and understand it’s correlation with obesity.

Subjects

The study was a retrospective case series conducted in the years 2000 to 2014, at the Aga Khan University Hospital (AKUH), Karachi, Pakistan where 156 patients who had been diagnosed and treated for TC were analyzed. Clinicopathological data was collected from medical records of these patients and weight and height were measured, pre-surgery, post-surgery, and at follow up. The BMI was correlated with patient variables for any significant associations.

Results

The patient set comprised of 38.5% males and 61.5% females with a mean age of 47.77 (SD ± 14.35). The BMI was significantly associated with age as 72.8% of participants were obese and >45 years old as compared to 27.2% who were under 45 years and obese (p-value <0.001). Upon comparison of the pre-surgery, post-surgery, and current mean BMI, Bonferroni pairwise comparisons showed no significant difference (p>0.999).

Conclusion 

The majority of-of TC patients among the Pakistani population were obese and female. Age was significantly associated with the risk of having a higher BMI. Moreover, differences in BMI pre and post-surgery could not be statistically proven.

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.

Increased level of DNA damage in some organs of obese Zucker rats by γ-H2AX analysis

In a recent study, we showed that lymphocytes of obese Italian children/adolescents displayed levels of double strand breaks (DSB), assayed as serine 139-phosphorylated histone H2AX (γ-H2AX), about eightfold higher than normal weight controls, and that 30% of this damage-generated micronuclei. These findings suggested that obese children could be at increased risk of obesity-mediated cancer later in life. We therefore aimed to assess the level of γ-H2AX in a genetic animal model of obesity (Zucker rat) to identify a genotoxic/carcinogenic risk in some organs. The DSB marker was studied in 3- to 4-week-old rats and in 9- to 13-week-old rats. Paraffin-embedded sections of heart, thyroid, liver, pancreas, lung, kidney, esophagus, and gut from the fa-/fa- (obese) and the fa+/fa- (lean) control animals were processed for immunohistochemistry detection of γ-H2AX. Pancreas (0.0624 ± 0.0195), lung (0.1197 ± 0.0217), esophagus (0.1230 ± 0.0351), kidney (0.1546 ± 0.0149), and gut (0.1724 ± 0.0352) of 9- to 13-week-old obese rats showed a higher proportion of γ-H2AX-positive nuclei, than their lean counterparts (0.0092 ± 0.0033, 0.0416 ± 0.0185, 0.0368 ± 0.0088, 0.0686 ± 0.0318, and 0.0703 ± 0.0239, respectively). No difference was seen in the 3- to 4-week-old age group with regard to obesity, indicating that the DNA damage increased with older age of the rats. We hypothesize that the organs of the obese animals showing high levels of DSB could represent target tissues for the development of obesity-related cancers. Environ. Mol. Mutagen. 58:477-484, 2017. © 2017 Wiley Periodicals, Inc.

Updated guidelines on the preoperative staging of thyroid cancer

Recent studies have provided prognostic information and recommendations for staging thyroid cancers that have changed the staging and management guidelines for the disease. Consequently, minimal extrathyroidal extension (ETE) was removed from the T3 stage classification in the eighth edition of the TNM staging system by the American Joint Committee on Cancer. New T categories have been subsequently added, including T3a, defined as a tumor >4 cm in its greatest dimension, limited to the thyroid gland, and T3b, defined as a tumor of any size with gross ETE invading only the strap muscles. In this article, the author reviews the changes in the TNM staging system for thyroid cancer, with an emphasis on ultrasonography in preoperative staging.

Pretreatment BMI Is Associated with Aggressive Clinicopathological Features of Papillary Thyroid Carcinoma: A Multicenter Study

OBJECTIVES

The aim of the present study was to analyze the association between pretreatment body mass index (BMI) and the aggressiveness of papillary thyroid carcinoma (PTC) along with its clinical outcomes in a Chinese population with BMI classification for Asians.

METHODS

A retrospective, observational study was conducted on patients from two teaching hospitals in China. 1622 classical PTC patients were categorized into four groups according to BMI.

RESULTS

We found that increased BMI was associated with extrathyroidal extension, multifocality, the presence of lymph node (LN) metastasis, and advancing TNM stage in PTC patients. Furthermore, compared to patients with normal weight, those in the overweight and obese group exhibited a significantly increased risk of extrathyroidal extension, multifocality, cervical LN metastasis, and advanced TNM stage. 40 and 37 patients experienced persistent and recurrent disease, respectively. No differences regarding persistent disease or recurrence were observed among the BMI groups.

CONCLUSION

A higher pretreatment BMI has been strongly associated with aggressive features of PTC according to the BMI classification for Asians. Obesity was not found to be associated with a greater risk of recurrence.

Insulin Resistance: Any Role in the Changing Epidemiology of Thyroid Cancer?

In the past few decades, the incidence of thyroid cancer (TC), namely of its papillary hystotype (PTC), has shown a steady increase worldwide, which has been attributed at least in part to the increasing diagnosis of early stage tumors. However, some evidence suggests that environmental and lifestyle factors can also play a role. Among the potential risk factors involved in the changing epidemiology of TC, particular attention has been drawn to insulin-resistance and related metabolic disorders, such as obesity, type 2 diabetes, and metabolic syndrome, which have been also rapidly increasing worldwide due to widespread dietary and lifestyle changes. In accordance with this possibility, various epidemiological studies have indeed gathered substantial evidence that insulin resistance-related metabolic disorders might be associated with an increased TC risk either through hyperinsulinemia or by affecting other TC risk factors including iodine deficiency, elevated thyroid stimulating hormone, estrogen-dependent signaling, chronic autoimmune thyroiditis, and others. This review summarizes the current literature evaluating the relationship between metabolic disorders characterized by insulin resistance and the risk for TC as well as the possible underlying mechanisms. The potential implications of such association in TC prevention and therapy are discussed.