Analysis of Malignant Thyroid Neoplasms with a Striking Rise of Papillary Microcarcinoma in an Endemic Goiter Region

Proportion of papillary thyroid microcarcinoma in Kerala, India, over a decade: a retrospective cohort study

Background

Overdiagnosis is a phenomenon where an indolent cancer is diagnosed that otherwise would not have caused harm to the patient during their lifetime. The rising incidence of papillary thyroid cancer (PTC) in various regions of the world is attributed to overdiagnosis. In such regions, the rates of papillary thyroid microcarcinoma (PTMC) are also rising. We aimed to study whether a similar pattern of rising PTMC is found in Kerala, a state in India, where there has been a doubling of thyroid cancer incidence over a decade.

Methods

We conducted a retrospective cohort study in two large government medical colleges, which are tertiary referral facilities in the state of Kerala. We collected data on the PTC diagnosis in Kozhikode and Thrissur Government Medical colleges from 2010 to 2020. We analysed our data by age, gender and tumor size.

Results

The incidence of PTC at Kozhikode and Thrissur Government Medical colleges nearly doubled from 2010 to 2020. The overall proportion of PTMC in these specimens was 18.9%. The proportion of PTMC only marginally increased from 14.7 to 17.9 during the period. Of the total incidence of microcarcinomas, 64% were reported in individuals less than 45 years of age.

Conclusion

The rise in the number of PTCs diagnosed in the government-run public healthcare centres in Kerala state in India is unlikely to be due to overdiagnosis since there was no disproportionate rise in rates of PTMCs. The patients that these hospitals cater to may be less likely to show healthcare-seeking behavior or ease of healthcare access which is closely associated with the problem of overdiagnosis.

Differential gene expression profile of multinodular goiter

Introduction

The goiter, a neglected heterogeneous molecular disease, remains a major indication for thyroidectomies in its endemic regions.

Objectives

This study analyzed differential gene expression in surgical specimens diagnosed with multi nodular and compared the data to that of thyroid tissue without multinodular goiter from patients undergoing thyroidectomy in Manaus-AM, Brazil using RNA-seq technology.

Methodology

The transcriptome information of the surgical specimen fragments with and without multinodular goiter was accessed by Illumina HiSeq 2000 New Generation Sequencing (NGS) using the RNA-seq NEBNext^® Ultra^™ RNA Library Prep Kit for Illumina^®—#E7530L protocol and differential gene expression analysis.

Results

Differences were found between the gene expression profiles of the diseased tissues and those of the healthy control tissues; at least 70 genes were differentially expressed. The HOTS gene was expressed only in multinodular goiter tissues (p < 0.05).

Conclusion

These results demonstrate that the gene expression profile of multinodular goiter is pro-tumoral and that HOTS can play a central role in multinodular goiter development.

Transcriptome Analysis Identified 2 New lncRNAs Associated with the Metastasis of Papillary Thyroid Carcinoma

INTRODUCTION

Papillary thyroid microcarcinoma (PTMC) is a specific subgroup of papillary thyroid carcinoma and defined with the dimension ≤1 cm by the WHO. Although it shows a relatively high 10-year livability, the metastasis of PTMC into other tissues and organs seriously affects the daily life of patients with relatively high mortality. Therefore, the genetic basis for the metastasis of PTMC needs to be explored for effective therapeutic targets. Here, we conducted a series of comparative analysis of the transcriptional expression profile between PTMC patients with and without lymph node metastasis.

METHODS

Gene expression profile and gene function were analyzed using RNA extracted from pathological tissues of 12 patients with PTMC, and the core biomarkers closely related to its metastasis were identified.

RESULTS

Our results showed that 7,507 genes and 42 RNAs showed remarkably different expression patterns. More sophisticated analysis showed that the high expression of 2 lncRNAs (T077499 and T004533) resulted in the metastasis of PTMC, which suggests that the expression pattern of the 2 lncRNAs may act as a potential biomarker for pathogenesis and prognosis of PTMC metastasis.

CONCLUSION

Our findings preliminarily reveal the molecular mechanisms for PTMC metastasis, which will provide vital reference for subsequent studies about the genetic basis and molecular targeted therapy for PTMC metastasis.

Evaluation of the Bethesda System and the ACR TIRADS in an Endemic Goiter Region

BACKGROUND

Various factors can affect incidence of thyroid disorders and disease profiles may show abrupt changes in endemic goitrous areas. In this study, it was aimed to analyze the American College of Radiology (ACR) Thyroid Imaging Reporting and Data System (TI-RADS) and the Bethesda System for Reporting Thyroid Cytopathology (BSRTC) in terms of risk of malignancy and general recommendations in an endemic goiter region (EGR).

METHODS

In this retrospective study, a total of 500 patients who had thyroidectomy following thyroid fine needle aspiration biopsy were enrolled. For the assessment of thyroid cytology, BSRTC was used and for the evaluation of ultrasound features of thyroid nodules, ACR TIRADS lexicon was adopted. For the assessment of thyroid cytology, Bethesda classification was used and for the evaluation of ultrasound features of thyroid nodules, ACR TIRADS lexicon was adopted.

RESULTS

In the EGR setting, benign category of BSRTC had a cancer risk of 6.2% which was two times more than the 2017 BSRTC revision reported. Nodules 10-14.9 mm in diameter had nearly 4 times higher malignancy risk than nodules >15 mm. In this group of patients, the risk of malignancy for TIRADS level 1, 2, 3, 4 and 5 was 1.16%, 2.94%, 7%, 45.64% and 94.44%, respectively. The malignancy rates for Bethesda system category I, II, III, IV, V and VI were as follows: 14.43%, 6.2%, 19.05%, 36.73%, 75.68% and 100%.

CONCLUSIONS

There are slight differences between the common set of standards and this study results regarding risk of malignancy. This brings up the question whether there is need for revision for the use of categories and the appropriate management in endemic goiter regions.