Increase in Thyroid Cancer Incidence Due to the Coronavirus Pandemic?

Delayed Diagnosis of Thyroid Cancer During the Pandemic

Restricting interpersonal contacts is one of the most effective measures against the spread of the SARS-CoV-2 coronavirus. From March 2020, personal contact between doctors and patients, particularly in primary care, was significantly limited, leading to a partial shift towards remote medicine. In some areas, this trend may not be viewed negatively; however, in endocrinology, it is virtually impossible to examine thyroid nodules or assess the recurrence of malignant disease in this manner. There was also a noted decrease in the number of fine needle aspiration biopsies (FNAB) performed due to their delay (except for tumors causing airway obstruction).

For example, at the Royal North Shore Hospital in Sydney, Australia, the majority of consultations (72%) between patients and endocrinologists occurred remotely from March to May 2020. By comparison, during the same period in 2019, only 4.9% of consultations were remote with a comparable number of consultations. Additionally, fewer FNABs were conducted (only 59%, 62%, and 63% in March, April, and May 2020, respectively, compared to the same months in 2019). Treatment of high-risk cancers proceeded standardly in March and April, but a significant decrease was observed in May (radioiodine ablation in 2020: March 93%, April 100%, and May 62% compared to the same periods in 2019).

Impact of Anti-Coronavirus Measures on Thyroid Cancer Treatment

The prognosis for patients with thyroid cancer depends on age, gender, histological type of the tumor, its extrathyroidal invasion, lymph node involvement, and the presence of distant metastases. During the peak of the pandemic, therapy timing had to consider both healthcare limitations and the risk of SARS-CoV-2 infection. There is evidence that most papillary cancers in younger patients (< 50 years) do not require urgent treatment and can be temporarily actively monitored. In contrast, advanced cancers (especially those causing airway obstruction or with distant metastases) require the fastest possible initiation of either surgical or systemic therapy. Physicians, therefore, focused on treating cancers that could not be delayed during this period.

However, a problem persists as many (a)symptomatic patients postponed their visits to the doctor. Preventive check-ups were also significantly fewer. At the peak of the first wave of the pandemic, a 58.4% reduction in nuclear medicine thyroid diagnostic tests and a 41.8% decrease in radioiodine therapy were observed in Europe. This trend also affected patients with multiple endocrine neoplasia (MEN2), where delays in genetic testing (including relatives) and prophylactic thyroidectomy were noted.

Thyroid Cancer as a Risk Factor for More Severe Course of COVID-19?

It has been proven that malignant tumors increase the risk of ICU admission and death in COVID⁺ patients (hazard ratio [HR] 3.50; 95% confidence interval [CI] 1.60–7.64). Due to the nature of thyroid cancer treatment and the overall condition of these patients, there is a generally increased risk of community respiratory infections, including SARS-CoV-2 infection.

Conclusion

The restriction of medical care during the coronavirus pandemic may result in an increase in the incidence of thyroid cancer and a rise in morbidity and mortality among these patients in the coming months.

Thyroid cancers generally grow slowly, but patients with aggressive tumors or advanced stages require the fastest possible initiation of treatment, regardless of the current epidemic situation.

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Source: Tsang V. H. M., Gild M., Glover A. et al. Thyroid cancer in the age of COVID-19. Endocr Relat Cancer 2020; 27 (11): 407–419, doi: 10.1530/ERC-20-0279.