Papillary Thyroid Cancer Trends in the Wake of the COVID-19 Pandemic: Is There a Shift toward a More Aggressive Entity?

Abstract

Background: Globally, the incidence of papillary thyroid cancer (PTC) has been increasing over the last few decades and it has become the second most common cancer in women in the UAE. There is some evidence to suggest that COVID-19 infection might be directly linked to the development of aggressive variants of PTC. The primary goal of this study was to compare the clinical and pathologic characteristics of thyroid cancer patients treated at the largest endocrine surgery center in Abu Dhabi before and after the COVID-19 pandemic outbreak.

Methods: This retrospective cohort analysis included patients who underwent elective thyroid surgery at Burjeel Hospital between January 2018 and December 2022. Patients were divided into two groups based on when the COVID-19 outbreak started: group one, comprising patients who had surgery between January 2018 and December 2019 (the "pre-pandemic group"), and group two, comprising patients who had surgery between January 2021 and December 2022 (the "post-pandemic group"). In addition to demographic data, clinicopathological factors, such as aggressive cell type, multifocality, tumor size and location, laterality, lympho-vascular invasion, and extrathyroidal extension, were assessed. We utilized the t-paired test for parametric variables and the Chi-square test for the cross-table analysis.

Results: During the study, 1141 people had thyroid surgery, with an annual average of 285 procedures. PTC cases recorded in the final histopathological samples rose from 111 in the pre-pandemic era to 182 in the post-pandemic era. Neither the female-to-male gender ratio, which was 90:21 in the pre-pandemic group and 142:40 in the post-pandemic group (p = 0.532), nor the median age, which was 39.1 and 40.1 years, respectively, varied significantly between the two groups. However, there was a significant increase between pre-pandemic and post-pandemic in the aggressive PTC variants (3% vs. 11.5%, p = 0.001), increased poor prognostic factors such as bilateral multifocality (10.8% vs. 32.4%, p = 0.000), as well as increased capsule-vascular tumor invasion (19.8% vs. 27%); on the other hand, the size of the single foci was 17 mm in the pre-pandemic group compared to 13 mm in the post-pandemic group (p = 0.001).

Conclusions: A significant rise in unfavorable prognostic markers and aggressive subtypes of PTC was seen post-pandemic in thyroidectomy patients operated on at a leading endocrine surgery center in the United Arab Emirates.

Keywords: COVID-19; PTC; extrathyroidal extension; lymph vascular invasion; pandemic; tall cell variant; thyroid cancer.

Figure 1

Comparison of the median tumor size found in final histopathology before and after the COVID-19 pandemic. * indicates significance using the t-test with p = 0.001.

Figure 2

The rate of aggressive, poor prognosis tall cell PTC in the final histopathology, before and after the COVID-19 pandemic, in comparison with classic and the better-prognosis follicular forms.