Changing patterns of thyroid cancer in different stages of Universal Salt Iodization in Peking Union Medical College Hospital, 1986-2018

Clinicopathological profile and management of thyroid carcinoma: a Sub-Saharan country experience

BACKGROUND

In Sudan, there is limited knowledge on the epidemiology, clinical characteristics and pathological patterns of thyroid cancer. To address this shortcoming, we studied the clinical, pathological and treatment patterns of thyroid cancer at the National Cancer Institute ‒ University of Gezira (NCI-UG), Sudan.

METHODS

We performed a retrospective health facility-based study of patients with thyroid cancer who were treated at NCI-UG from January 2009 to December 2017.

RESULTS

A total of 139 patients with thyroid cancer were identified during the study period. Tumors were more common among women (69%). Goiter was the main presenting symptom (85%). The most common type of thyroid cancer was follicular carcinoma (41%), followed by papillary carcinoma (24%), then anaplastic carcinoma (20%). The mean age of the women was 56.3 years (SD ± 14.7), compared to 52.5 years (SD ± 16.6) for the men. The frequencies of stage I, II, III, and IV were 17%, 22%, 16%, and 45%, respectively. Different types of thyroidectomies were performed in 79% of the cases, lobectomy in 4%, and no surgery in 17%. Only 28% of the cases received radioactive iodine. Palliative chemotherapy and radiotherapy were prescribed to 17% and 37% of the cases, respectively.

CONCLUSION

Thyroid cancer is more prevalent among women and most patients present at later stages. The dominance of follicular type suggests that the majority of this population is iodine-deficient.

Iodine nutrition and papillary thyroid cancer

Thyroid cancer (TC) is the most frequent endocrine malignancy. The incidence of TC, especially papillary thyroid carcinoma (PTC), has continued to rise all over the world during the past few years, for reasons that are not entirely clear. Though the phenomenon of overdiagnosis is occurring, it is not the sole driver of the substantial increase in incidence. Lifestyle, environmental factors, or complications are considered to be potential risk factors. Among these factors, iodine is a micronutrient that is vital to thyroid function. The effect of iodine intake on PTC has been controversial for many years and the epidemiological or experimental studies provided diametrically opposite conclusions. Combining all these studies, we found that iodine nutrition may affect the overall prevalence, distribution of the histological types, and clinicopathological aggressiveness of TC, especially PTC. However, the available evidence is poor due to the impact of various internal and external related factors. Therefore, this article sums up available results from both epidemiological and experimental studies, future studies are also warranted to expound on the relationship between overall PTC prevalence and iodine intake.

Expression Profile and Diagnostic Significance of MicroRNAs in Papillary Thyroid Cancer

The incidence of papillary thyroid cancer (PTC) has increased in recent years. To improve the diagnostic management of PTC, we propose the use of microRNAs (miRNAs) as a biomarker. Our aim in this study was to evaluate the miRNA expression pattern in PTC using NanoString technology. We identified ten miRNAs deregulated in PTC compared with reference tissue: miR-146b-5p, miR-221-3p, miR-221-5p, miR-34-5p, miR-551b-3p, miR-152-3p, miR-15a-5p, miR-31-5p, and miR-7-5p (FDR < 0.05; |fold change (FC)| ≥ 1.5). The gene ontology (GO) analysis of differentially expressed miRNA (DEM) target genes identified the predominant involvement of epidermal growth factor receptor (EGFR), tyrosine kinase inhibitor resistance, and pathways in cancer in PTC. The highest area under the receiver operating characteristic (ROC) curve (AUC) for DEMs was found for miR-146-5p (AUC = 0.770) expression, indicating possible clinical applicability in PTC diagnosis. The combination of four miRNAs (miR-152-3p, miR-221-3p, miR-551b-3p, and miR-7-5p) showed an AUC of 0.841. Validation by real-time quantitative polymerase chain reactions (qRT-PCRs) confirmed our findings. The introduction of an miRNA diagnostic panel based on the results of our study may help to improve therapeutic decision making for questionable cases. The use of miRNAs as biomarkers of PTC may become an aspect of personalized medicine.