Association between Obesity Indexes and Thyroid Cancer Risk in Korean Women: Nested Case-Control Study

The American Thyroid Association risk stratification and long-term outcomes of differentiated thyroid cancer: a 20-year follow-up of patients in Saudi Arabia

Background

Studies have reported differing factors associated with poor outcomes in patients with differentiated thyroid cancer (DTC). We aimed to describe our 20 years of experience in the management of thyroid cancer (TC) and identify predictors of treatment outcomes.

Methods

We conducted a retrospective review of medical records of patients with TC seen in the Thyroid Center at King Saud University Medical City (KSUMC) in Riyadh, Saudi Arabia, between the years 2000 and 2020. Demographic and clinical data including pathological characteristics were collected. The American Thyroid Association (ATA) risk stratification was determined for all patients at the postoperative period as well as the response to therapy at the final follow-up visit.

Results

A total of 674 patients (mean age: 47.21 years) with TC, 571 (84.7%) of which were women, were included. There were 404 (60.0%) patients with ATA low risk, 127 (18.8%) with intermediate risk, and 143 (21.2%) with high-risk histology. Overall, 461 patients (68.4%) had an excellent response to treatment, 65 (9.6%) had an indeterminate response, 83 (12.3%) had a biochemical incomplete response, and 65 (9.6%) had a structural incomplete response. Patients who had an excellent response were mostly ATA low risk (n = 318 of 431, 68.1%), whereas 40 of 65 patients (61.5%) of those with ATA high-risk histology had a structural incomplete response to treatment. There were significantly more women who had an excellent response compared with men. Obesity, lymphovascular invasion, and size of the tumor were significant predictors of worse outcomes to therapy.

Conclusion

Tumor size, lymphovascular invasion, and obesity are strong predictors of a worse response to therapy among patients with TC. Patients with obesity should be carefully followed up regardless of their risk stratification in light of the recent compelling evidence associating obesity with thyroid cancer and its higher risk of a worse disease outcome. ATA risk stratification is well correlated with patient long-term outcomes.

Obesity and thyroid cancer risk

PURPOSE OF REVIEW

This review explores recent evidence assessing the relationship between obesity and thyroid cancer.

RECENT FINDINGS

Consistent evidence from observational studies suggests that obesity increases the risk of thyroid cancer. The relationship persists when alternative measures of adiposity are used, but the strength of association may vary according to the timing and duration of obesity and how obesity or other metabolic parameters are defined as exposures. Recent studies have reported an association between obesity and thyroid cancers that are larger or have adverse clinicopathologic features, including those with BRAF mutations, thus providing evidence that the association is relevant for clinically significant thyroid cancers. The underlying mechanism for the association remains uncertain but may be driven by disruption in adipokines and growth-signaling pathways.

SUMMARY

Obesity is associated with an increased risk of thyroid cancer, although further research is required to understand the biological mechanisms underpinning this relationship. Reducing the prevalence of obesity is predicted to lessen the future burden of thyroid cancer. However, the presence of obesity does not impact current recommendations for screening or management of thyroid cancer.

Thyroid Nodules and Obesity

A widely discussed topic in the pathophysiology of thyroid nodules is the role of obesity, a state that leads to increased systemic inflammatory markers. Leptin plays a vital role in forming thyroid nodules and cancer through several mechanisms. Together with chronic inflammation, there is an augmentation in the secretion of tumor necrosis factor (TNF) and the cytokine interleukin 6 (IL-6), which contributed to cancer development, progression and metastasis. In addition, leptin exerts a modulatory action in the growth, proliferation and invasion of thyroid carcinoma cell lines via activating various signal pathways, such as Janus kinase/signal transducer and activator of transcription, mitogen-activated protein kinase (MAPK) and/or phosphoinositide 3-kinase (PI3K)/protein kinase B (Akt). Through several proposed mechanisms, aberrant endogenous estrogen levels have been suggested to play a vital role in the development of both benign and malignant nodules. Metabolic syndrome triggers the development of thyroid nodules by stimulating thyroid proliferation and angiogenesis due to hyperinsulinemia, hyperglycemia and dyslipidemia. Insulin resistance influences the distribution and structure of the thyroid blood vessels. Insulin growth factor 1 (IGF-1) and insulin affect the regulation of the expression of thyroid genes and the proliferation and differentiation of thyroid cells. TSH can promote the differentiation of pre-adipocytes to mature adipocytes but also, in the presence of insulin, TSH possesses mitogenic properties. This review aims to summarize the underlying mechanisms explaining the role of obesity in the pathophysiology of thyroid nodules and discuss potential clinical implications.

[Clinical study of bilateral axillo-breast approach robot in obese women with thyroid cancer]

Objective:To explore the safety and feasibility of bilateral axillo-breast approach （BABA） robot in the operation of thyroid cancer in obese women. Methods:The clinical data of 81 obese female patients who underwent da Vinci robotic thyroid cancer surgery（robotic group） at the Department of Thyroid and Breast Surgery, PLA 960 Hospital from May 2018 to December 2021 were retrospectively analyzed and compared with the clinical data of 106 obese female thyroid cancer patients who underwent open surgery（open group） during the same period. The age, body mass index（BMI）, mean time of surgery, mean postoperative drainage, tumor diameter, postoperative tumor stage, number of lymph node dissection in the central and lateral cervical regions, number of positive lymph nodes in the central and lateral cervical regions, postoperative cosmetic outcome satisfaction score, mean postoperative hospital stay and postoperative complications of all patients were counted. The results were analyzed using SPSS 26.0 statistical software, and the count data were compared using the χ² test, and the measurement data were compared using the t test. Results:All patients completed the operation successfully, and there was no conversion in the robot group, postoperative pathological results were all composed of papillary thyroid carcinoma. The operation time in the robot group was（144.62±36.38） min, which was longer than that in the open group（117.06±18.72） min（P<0.05）. The average age of the robot group was（40.25±9.27） years, which was lower than that of the open group（49.59±8.70） years（P<0.05）. The satisfactory score of cosmetic effect in the robot group（9.44±0.65） was higher than that in the open group（5.23±1.07）（P<0.05）. There was no significant difference in tumor diameter, BMI, average postoperative drainage, temporary hypoparathyroidism and recurrent laryngeal nerve injury, number of central and lateral cervical lymph node dissection, number of positive lymph nodes in the central and lateral cervical regions, and average postoperative hospital stay between the two groups. There was no permanent hypoparathyroidism and recurrent laryngeal nerve injury in both groups. Conclusion:The application of BABA pathway robot in thyroid cancer surgery in obese women is safe and feasible, and the cosmetic effect is better after operation.