BACKGROUND
Thyroid nodules are very common, occurring in up to 50% of adults. The concern regarding thyroid nodules is whether the nodule is a cancer. The most common way to determine this is to do a biopsy of the nodule. About 5-6% of biopsies reveal papillary thyroid cancer and ~85% are benign (non-cancerous). However, 10-15% are called indeterminate, meaning the cells are not entirely normal but not entirely abnormal either. Sometimes, evaluating the cells for certain molecular markers that are seen in cancers can help determine whether surgery is needed. However, in areas that do not have access to molecular markers, surgery is usually recommended.

During the COVID-19 pandemic, many healthcare resources were diverted to focus on minimizing the spread of infectious diseases and on providing care to patients with COVID-19 infection. In this context, non-urgent and elective procedures for non-infectious diseases were often delayed. Worldwide, this resulted in delays in the diagnosis and treatment of many cancer types, including breast and colorectal cancers. However, the impact of such healthcare delays on more slow-growing cancers such as some thyroid cancer types, is unclear.

This study, which was focused on patients with a diagnosis of indeterminate thyroid nodules based on results of the thyroid biopsy, aimed to 1) determine to what extent thyroid surgery for indeterminate thyroid nodules was reduced during the COVID-19 pandemic; and 2) to determine whether or not the delay in thyroid surgery was associated with an increased occurrence of more aggressive thyroid cancer.

THE FULL ARTICLE TITLE
Medas F et al 2023 Effect of the COVID-19 pandemic on surgery for indeterminate thyroid nodules (THYCOVID): A retrospective, international, multicentre, cross-sectional study. Lancet Diabetes 11:402–413. PMID: 37127041.

SUMMARY OF THE STUDY
The study included data from 87,467 thyroid surgeries that took place at 157 centers in 49 countries. About one-quarter (22,974, 26%) of the thyroid surgeries were performed for a diagnosis of indeterminate thyroid nodules. The patients were divided into three groups: group 1 underwent thyroid surgery during the pre-pandemic phase (between January 1, 2019 and Feb 20, 2020), group 2 underwent thyroid surgery during the pandemic escalation phase (between March 1, 2020 and May 31, 2021), and group 3 underwent thyroid surgery during the pandemic decrease phase (between June 1, 2021 and December 31, 2021).

Analysis of the data found that there were relatively fewer thyroid surgeries performed during the pandemic escalation phase (group 2). Furthermore, compared to the pre-pandemic phase (group 1), there was an increase in the use of molecular testing as part of the evaluation of thyroid nodules prior to surgery during the pandemic decrease phase (group 3). Among the patients with indeterminate thyroid nodules who received thyroid surgery, there was an increase in the rate of thyroid cancer detected between group 1 and group 3 (39% in the pre-pandemic phase vs 42% in the pandemic escalation phase), and between group 2 and group 3 (39% in the pandemic escalation phase vs 42% in the pandemic decrease phase). Compared to the thyroid cancers that were diagnosed during the pre-pandemic phase (group 1), thyroid cancers diagnosed during the pandemic decrease phase (group 3) were larger in cancer size, more likely to have spread to lymph nodes, and associated with a higher risk of thyroid cancer recurrence.

WHAT ARE THE IMPLICATIONS OF THIS STUDY?
This study showed that surgery for indeterminate thyroid nodules decreased during the COVID-19 pandemic. In addition, the number of thyroid cancers at high risk for recurrence significantly increased the postpandemic period. Thus, the study findings suggest that thyroid surgery, when appropriate for the management of indeterminate thyroid nodules, should not be delayed.

— Debbie Chen, MD

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