Most patients with a small papillary thyroid carcinoma enjoy an excellent prognosis and may be managed with minimally invasive therapy or active surveillance

Follow-up and Outcomes of 186 Patients With Follicular Cell-Derived Thyroid Cancer Seen at a Referral Center by One Thyroidologist in 2015

OBJECTIVE

To study the profile, management, and outcomes of follicular cell-derived thyroid cancer (FCDTC) before publication of the 2016 American Thyroid Association guidelines recommending less-aggressive thyroid cancer procedures.

METHODS

Patients with FCDTC were seen by one thyroidologist at Mayo Clinic during the 2015 calendar year. Patients underwent surgical procedures for FCDTC in 2015 or earlier at Mayo Clinic or another institution. Follow-up data were collected from January 1, 2016, through July 20, 2022. Outcomes measured included tumor characteristics, treatment methods, adverse effects, diagnostic imaging methods, and primary tumor/metastasis status at the last follow-up.

RESULTS

Of 186 included patients, 85 had total or near-total thyroidectomy. Bilateral disease was present in 35.5% of these patients, and contralateral involvement would have been missed by lobectomy for 9 (10%) patients with low-risk thyroid cancer. Additionally, 57% had positive neck lymph nodes identified during their surgical procedure, 25% (21% in central compartment) of which were undetected by preoperative ultrasonography. At the last follow-up, 65.6% of patients had no evidence of disease and 10.7% had distant metastases.

CONCLUSION

This report outlines the profile and outcomes of patients with FCDTC who were treated at a referral center before the revised 2016 American Thyroid Association guidelines. Lobectomy for low-risk FCDTC may miss some cancer in the contralateral lobe. However, the clinical importance of these missed microcarcinomas is unclear. Preoperative ultrasonography effectively predicts lateral, but not central compartment, nodal metastases.

Development and Validation of a Computed Tomography-Based Radiomics Nomogram for the Preoperative Prediction of Central Lymph Node Metastasis in Papillary Thyroid Microcarcinoma

RATIONALE AND OBJECTIVES

This study aims to develop and validate a computed tomography (CT)-based radiomics nomogram for pre-operatively predicting central lymph node metastasis (CLNM) in patients with papillary thyroid microcarcinoma (PTMC) and explore the underlying biological basis by using RNA sequencing data.

METHODS

This study trained 452 PTMC patients across two hospitals from January 2012 to December 2020. The sets were randomly divided into the training (n = 339), internal test (n = 86), external test (n = 27) sets. Radiomics features were extracted from primary lesion's pre-operative CT images for each patient. After screening for features, five algorithms such as K-nearest neighbor, logistics regression, linear-support vector machine (SVM), Gaussian SVM, and polynomial SVM were used to establish the radiomics models. The performance of these five algorithms was evaluated and compared directly to radiologist's interpretation (CT-reported lymph node status). The radiomics signature score (Rad-score) was generated using a linear combination of the selected features. By combining the clinical risk factors and Rad score, a radiomics nomogram was established and compared with Rad-score and clinical model. The performance of the nomogram was evaluated based on the receiver operating characteristic (ROC) curve, calibration curve, and the decision curve analysis (DCA). The potential biological basis of nomogram was revealed by performing genetic analysis based on the RNA sequencing data.

RESULTS

A total of 25 radiomic features were ultimately selected to train the machine learning models, and the five machine learning models outperformed the radiologists' interpretation by achieving area under the ROC curves (AUCs) ranging from 0.606 to 0.730 in the internal test set. By incorporating the Rad score and clinical risk factors (sex, age, tumor-diameter, and CT-reported lymph node status), this nomogram achieved AUCs of 0.800 and 0.803 in the internal and external test set, which were higher than that of the Rad-score and clinical model, respectively. Calibration curves and DCA also showed that the nomogram had good performance. As for the biological basis exploration, in patients predicted by nomogram to be PTC patients with CLMN, 109 genes were dysregulated, and some of them were associated with pathways and biological processes such as tumor angiogenesis.

CONCLUSION

This radiomics nomogram successfully identified CLNM on pretreatment imaging across multiple institutions, exceeding the diagnostic ability of radiologists and had the potential to be integrated into clinical decision making as a non-invasive pre-operative tool.

The Asian Thyroid Working Group, from 2017 to 2023

The Asian Thyroid Working Group was founded in 2017 at the 12th Asia Oceania Thyroid Association (AOTA) Congress in Busan, Korea. This group activity aims to characterize Asian thyroid nodule practice and establish strict diagnostic criteria for thyroid carcinomas, a reporting system for thyroid fine needle aspiration cytology without the aid of gene panel tests, and new clinical guidelines appropriate to conservative Asian thyroid nodule practice based on scientific evidence obtained from Asian patient cohorts. Asian thyroid nodule practice is usually designed for patient-centered clinical practice, which is based on the Hippocratic Oath, "First do not harm patients," and an oriental filial piety "Do not harm one's own body because it is a precious gift from parents," which is remote from defensive medical practice in the West where physicians, including pathologists, suffer from severe malpractice climate. Furthermore, Asian practice emphasizes the importance of resource management in navigating the overdiagnosis of low-risk thyroid carcinomas. This article summarizes the Asian Thyroid Working Group activities in the past 7 years, from 2017 to 2023, highlighting the diversity of thyroid nodule practice between Asia and the West and the background reasons why Asian clinicians and pathologists modified Western systems significantly.

Trends in the incidence of thyroid cancer in Incheon Province, South Korea, from 2004 to 2013: A representative sample study from Incheon cancer registry

AIM

This study aimed to assess the trends in the incidence of thyroid cancer in Incheon Province, South Korea, from 2004 to 2013 and to identify its association with thyroid cancer screening.

METHODS

We evaluated randomly sampled data of 10% of thyroid cancer patients collected between 2004 and 2013 from the Incheon Cancer Registry, Incheon, South Korea. The expected annual incidence rates of thyroid cancer from 2004 to 2013 were calculated, and the trends in annual incidence change were assessed using a Poisson regression model. In addition, the annual proportion change in the thyroid cancer population according to the detection method and tumor size was also calculated by evaluating the linear-by-linear association.

RESULTS

The average expected prevalence of thyroid cancer was 30 per 100,000 individuals from 2004 to 2013. The expected annual incidence of thyroid cancer per 100,000 individuals increased from 7 in 2004 to 49 in 2013, with an annual 1.25-fold difference (p < 0.001). Screening helped improve the detection of thyroid cancer annually, with the proportion increasing by screening detection (p < 0.001). Majority (54%) of the tumors were small (< 10 mm) and their detection rate increased from 2004 to 2013 (p < 0.001).

CONCLUSIONS

The incidence of thyroid cancer has increased from 2004 to 2013 in Incheon Province, South Korea, with the increase being most significant for small tumors. These findings indicate that the increased incidence is primarily due to the widespread use of screening and not an actual increase in clinically significant thyroid cancer.

Management of Incidentalomas

Incidental findings are common in the evaluation of surgical patients. Understanding the appropriate assessment and management of these frequent occurrences is important for the provision of comprehensive quality care. This review details the epidemiology, considerations, and recommendations for management of common incidental manifestations in surgical patients, including Meckel diverticulum, adrenal incidentaloma, thyroid nodule, solitary pulmonary nodule, small bowel intussusception, gallstones, and incidental appendectomy.

Active surveillance for thyroid Cancer: a qualitative study of barriers and facilitators to implementation

BACKGROUND

The 2015 American Thyroid Association guidelines supported active surveillance (AS) as a strategy for managing select low-risk thyroid cancers. Data examining physicians' attitudes about the acceptability of this option are limited. This study aimed to characterize the barriers and facilitators to implementing AS as perceived by practicing endocrinologists and surgeons in the United States.

METHODS

We conducted 24 semi-structured interviews probing physicians' attitudes toward AS for patients with small, low-risk thyroid cancer. We used deductive content analysis guided by a well-known model of guideline implementation. Analysis characterized concepts and themes related to AS implementation as physician, guideline, or external factors. We performed member checking to validate results.

RESULTS

The most prominent barriers to AS were related to physician factors, although guideline-specific and external barriers were also observed. Physician attitudes towards AS comprised the majority of physician-related barriers, while lack of knowledge about the guideline was also discussed. Participants' concerns about the potential negative outcomes resulting from observing a cancer were notable as were the lack of confidence in performing and offering surveillance. Beliefs about patient expectations and lack of knowledge about the guideline were also identified as barriers to offering surveillance. Guideline-specific and external barriers included the vagueness of surveillance protocols, lack of data supporting active surveillance, and societal beliefs about cancer. Facilitators of active surveillance included patients' desire to avoid surgery and shared decision-making.

CONCLUSIONS

Barriers and facilitators of active surveillance for low-risk thyroid cancers exist at multiple levels. Strategies to increase adoption of active surveillance should focus on physicians' attitudes, patient expectations, data supporting surveillance outcomes, and promoting societal-level acceptance of surveillance.

Therapeutic Strategy in Low-Risk Papillary Thyroid Carcinoma - Long-Term Results of the First Single-Center Prospective Non-Randomized Trial Between 2011 and 2015

Optimal therapeutic strategy in low advanced papillary thyroid carcinoma (PTC) is still a matter of debate. The management differs depending on the country. A prospective non-randomized study was performed to evaluate whether less extensive surgery could be a safe, acceptable, and sufficient therapeutic option in PTC cT1N0M0 patients. The present paper summarizes the results of over a 5-year follow-up.

MATERIAL

Our prospective group (PG) treated between 2011 and 2015 consisted of 139 patients with cT1aN0M0 PTC who underwent lobectomy (LT) as initial surgical treatment (PGcT1aN0M0 group) and 102 cT1bN0M0 patients in whom total thyroidectomy (TT) with unilateral central neck dissection (CND) was performed (PGcT1bN0M0). PG was compared with the retrospective group (RG) of patients who underwent TT with bilateral CND between 2004 and 2006: 103 cT1aN0M0 patients (RGcT1aN0M0) and 91cT1bN0M0 (RGcT1bN0M0). The risks of reoperation, cancer relapse and postoperative complications were analyzed.

RESULTS

Only 12 cT1aN0M0 patients (7.6%) withdrew from the trial and underwent TT with bilateral CND. Over 90% of patients accepted less extensive surgery. In 4 cT1aN0M0 cases, TT with CND was performed due to lymph node metastases found intraoperatively. The initial clinical stage according to the TNM/AJCC 7^th edition was confirmed histologically in 77% of cases in PGT1aN0M0 and in 72% in PGT1bN0M0, respectively. 24 PGcT1aN0M0 patients were reoperated on. In this group, cancer lesions in the postoperative histological specimens were found in 8 cases (32%). Five-year disease-free survival (DFS) was excellent. However, no statistically significant differences were found between PG and RG groups (99.3% in PGcT1aN0M0 and 99.0%, in RGcT1aN0M0; p = 0.41 and 98%, in PGcT1bN0M0 and 94.4% in RGcT1bN0M0; p=0.19). No significant differences were observed in the incidence of early paresis of the recurrent laryngeal nerves between PG and RG. However, as predicted, LT completely eliminated the risk of postoperative hypoparathyroidism.

SUMMARY

The results of the prospective clinical trial confirm that less extensive surgery in adequately selected low-advanced PTC patients is both safe and sufficient.

Factors Associated With Diagnosis and Treatment of Thyroid Microcarcinomas

CONTEXT

Nearly one-third of all thyroid cancers are ≤1 cm.

OBJECTIVE

To determine diagnostic pathways for microcarcinomas vs larger cancers.

DESIGN/SETTING/PARTICIPANTS

Patients from Georgia and Los Angeles Surveillance, Epidemiology, and End Results (SEER) registries with differentiated thyroid cancer diagnosed in 2014 or 2015 were surveyed. Survey data were linked to SEER data on tumor and treatment characteristics. Multivariable logistic regression analysis was performed.

MAIN OUTCOME MEASURES

Method of nodule discovery; reason for thyroid surgery.

RESULTS

Of patients who underwent surgery, 975 (38.2%) had cancers ≤1 cm, and 1588 cancers (61.8%) were >1 cm. The reported method of nodule discovery differed significantly between patients with cancers ≤1 cm and those with cancers >1 cm (P < 0.001). Cancer ≤1 cm was associated with nodule discovery on thyroid ultrasound (compared with other imaging, OR, 1.59; 95% CI, 1.21 to 2.10), older patient age (45 to 54 years vs ≤44, OR, 1.45; 95% CI, 1.16 to 1.82), and female sex (OR, 1.51; 95% CI, 1.22 to 1.87). Hispanic ethnicity (OR, 0.71; 95% CI, 0.57 to 0.89) and Asian race (OR, 0.67; 95% CI, 0.49 to 0.92) were negative correlates. Cancers ≤1 cm were associated with lower likelihood of surgery for a nodule suspicious or consistent with cancer (OR, 0.48; 95% CI, 0.40 to 0.57).

CONCLUSION

Thyroid microcarcinomas are more likely to be detected by ultrasound and less likely to be associated with surgery scheduled for known thyroid cancer. Understanding diagnostic pathways allows for targeted interventions to decrease overdiagnosis and overtreatment.

Computed Tomography for Detecting Cervical Lymph Node Metastasis in Patients Who Have Papillary Thyroid Microcarcinoma with Tumor Characteristics Appropriate for Active Surveillance

Background: Active surveillance (AS) has been considered one of the management options in patients with low-risk papillary thyroid microcarcinoma (PTMC). It is important to evaluate clinical lymph node (LN) metastasis to select appropriate candidates with low-risk disease. We investigated the predictive accuracy of computed tomography (CT) for cervical LN metastasis in patients who have PTMC with tumor characteristics appropriate for AS. Methods: This was a retrospective study. Medical records from December 2014 to the end of 2016 were reviewed. Patients who underwent thyroidectomy and who had pathologically confirmed PTMC were included. A total of 464 patients who had tumors with ultrasound (US) characteristics appropriate for AS and who underwent preoperative CT were included in the analysis. Results: CT showed higher diagnostic values especially in positive predictive value (PPV) than US. In patient-based analyses, CT showed low sensitivity and negative predictive value (NPV) (16.0% and 58.5%, respectively), but high specificity and PPV (99.6% and 97.1%, respectively) for detecting cervical LN metastasis. Similar trends were observed for the results of the central neck-level by CT (sensitivity, 14.9%; specificity, 97.4%; PPV, 82.9%; and NPV, 57.4%) in level-by-level analyses. When restricted to lateral neck levels, CT showed high diagnostic accuracy of 95.4% for detecting LN metastasis. In all analyses, CT showed better diagnostic values for cervical LN metastasis than US. Combining US and CT did not improve the diagnostic accuracy compared with CT. Conclusions: In patients with PTMC whose tumor has characteristics suitable for AS, CT had additional benefit after cervical LN assessment by US. Further studies are needed to evaluate routine initial CT scanning for patients who are candidates for AS.

Comparison of the prevalence of incidental and non-incidental papillary thyroid microcarcinoma during 2008-2016: a single-center experience

Background

The incidence of papillary thyroid microcarcinoma (PTMC) is increasing; however, it is not clear whether this reflects an increase in the incidence of incidental or in that of non-incidentally (presurgically) discovered PTMC (IPTMC vs. NIPTMC). We assessed the incidence of IPTMC and NIPTMC over the past 9 years, to discern whether the increase in PTMC incidence is due to improved diagnostics or to a real increase in the incidence.

Methods

We performed a retrospective chart review of 4327 patients who were consecutively admitted to and surgically treated for thyroid pathology at a single institution. As a main presurgical diagnostic test, all patients underwent ultrasound-guided fine-needle aspiration biopsy (UG-FNAB). The analyzed time frame was divided into three equal periods (I: 2008–2010, II: 2011–2013, III: 2014–2016), and IPTMCs and NIPTMCs were assessed and compared in each period.

Results

We evaluated 393 (9.08%) patients with thyroid malignancy, of which 156 (3.60% of all thyroid tumors [TTs]; 39.69% of all thyroid cancers [TCs]) were diagnosed as PTMC. The prevalence of NIPTMC among all TCs increased from 16.66% in 2008 to 33.75% in 2016, while that of IPTMC decreased from 20.83% in 2008 to 13.75% in 2016. The incidence rates of NIPTMC and IPTMC in period III differed statistically significantly (p < 0.0001). The prevalence rate of NIPTMC in period III was higher than that in period II, yet comparable to that in period I (p = 0.0014; p = 0.2804, respectively).

Conclusions

The prevalence of NIPTMC, rather than that of IPTMC, is escalating; this may be due to better presurgical diagnosis.

Clinicopathological Features and Prognosis of Papillary Thyroid Microcarcinoma for Surgery and Relationships with the BRAFV600E Mutational Status and Expression of Angiogenic Factors

Objective

To investigate the clinicopathological characteristics of papillary thyroid microcarcinoma (PTMC) for surgery by comparing the difference between PTMC and larger papillary thyroid carcinoma (LPTC).

Methods

We analyzed the differences in the clinicopathological characteristics, prognosis, B-type RAF kinase (BRAF)^V600E mutational status and expression of angiogenic factors, including pigment epithelium-derived factor (PEDF), Vascular Endothelial Growth Factor (VEGF), and hypoxia-inducible factor alpha subunit (HIF-1α), between PTMC and LPTC by retrospectively reviewing the records of 251 patients with papillary thyroid carcinoma, 169 with PTMC, and 82 with LPTC (diameter >1 cm).

Results

There were no significant differences in the gender, age, multifocality, Hashimoto’s thyroiditis, TNM stage, PEDF protein expression, rate of recurrence, or mean follow-up duration between patients with PTMC or LPTC. The prevalence of extrathyroidal invasion (EI), lymph node metastasis (LNM), and BRAF mutation in patients with PTMC was significantly lower than in patients with LPTC. In addition, in PTMC patients with EI and/or LNM and/or positive BRAF (high-risk PTMC patients), the prevalence of extrathyroidal invasion, Hashimoto's disease, lymph node metastasis, tumor TNM stage, PEDF positive protein expression, the rate of recurrent disease, and the mRNA expression of anti-angiogenic factors was almost as high as in patients with larger PTC, but with no significant difference.

Conclusions

Extrathyroid invasion, lymph node metastases, and BRAF^V600E mutation were the high risk factors of PTMC. PTMC should be considered for the same treatment strategy as LPTC when any of these factors is found. Particularly, PTMC with BRAF^V600E gene mutations needed earlier surgical treatment. In addition, the high cell subtype of PTMC with BRAF^V600E gene mutation is recommended for total thyroidectomy in primary surgery to reduce the risk of recurrence.

Association between screening and the thyroid cancer "epidemic" in South Korea: evidence from a nationwide study

OBJECTIVE

 To investigate whether screening for thyroid cancer led to the current "epidemic" in South Korea.

DESIGN

 Review of the medical records of nationally representative samples of patients with a diagnosis of thyroid cancer in 1999, 2005, and 2008.

SETTING

 Sample cases were randomly selected from South Korea's nationwide cancer registry, using a systematic sampling method after stratification by region.

PARTICIPANTS

 5796 patients with thyroid cancer were included (891 in 1999, 2355 in 2005, and 2550 in 2008).

MAIN OUTCOME MEASURES

 The primary outcome was age standardised incidence of thyroid cancer and the changes in incidence between 1999 and 2008 according to the methods used to detect tumours (screen detection versus clinical detection versus unspecified).

RESULTS

 Between 1999 and 2008, the incidence of thyroid cancer increased 6.4-fold (95% confidence interval 4.9-fold to 8.4-fold), from 6.4 (95% confidence interval 6.2 to 6.6) per 100 000 population to 40.7 (40.2 to 41.2) per 100 000 population. Of the increase, 94.4% (34.4 per 100 000 population) were for tumours less than 20 mm, which were detected mainly by screening. 97.1% of the total increase was localised and regional tumours according to the Surveillance, Epidemiology, and End Results (SEER) summary stage. Where cases were clinically detected, 99.9% of the increased incidences (6.4 per 100 000 population) over the same period were tumours less than 20 mm.

CONCLUSION

 The current "epidemic" of thyroid cancer in South Korea is due to an increase in the detection of small tumours, most likely as a result of overdetection. Concerted efforts are needed at a national level to reduce unnecessary thyroid ultrasound examinations in the asymptomatic general population.

What is the Minimal Surgery for Papillary Thyroid Carcinoma?

Although thyroid surgery for treatment of papillary thyroid carcinoma (PTC) has been practiced for more than 100 years, there is still controversy regarding the minimal surgery needed for cure. The main reason for this controversy is lack of prospective randomized trials. The data accumulated in the last four decades indicate that hemithyroidectomy can be sufficient and safely practiced in low-risk patients with PTC. Patients <45 years of age with a single tumor less than 2 cm, with no lymphatic spread, and in the absence of other risk factors, can be equally managed by hemithyroidectomy or total thyroidectomy. A slight increase in the risk of vocal cord paralysis and hypocalcemia after total thyroidectomy suggests that hemithyroidectomy is appropriate for the management of patients with stage T1 disease. Any choice regarding the extent of surgery should be made with the patient and his family and in a multidisciplinary setup, which has been shown to improve decision-making procedures before the operation and during follow-up.