Charting the Unknown Association of COVID-19 with Thyroid Cancer, Focusing on Differentiated Thyroid Cancer: A Call for Caution

Abstract

Background: Conceived of as the “silver lining” of the dark cloud of the coronavirus disease 2019 (COVID-19) pandemic, lessons taught by this catastrophe should be leveraged by medical authorities and policy makers to optimize health care globally. A major lesson is that resilient health systems should absorb sudden shocks incited by overwhelming health emergencies without compromising the continuum of care of chronic diseases, especially of cancer. Methods: The present review dissects the association between COVID-19 and thyroid cancer (TC), especially with differentiated TC (DTC), focusing on available data, knowledge gaps, current challenges, and future perspectives. Results: Obesity has been incriminated in terms of both COVID-19 severity and a rising incidence of TC, especially of DTC. The current conceptualization of the pathophysiological landscape of COVID-19–(D)TC association implicates an interplay between obesity, inflammation, immunity, and oxidative stress. Whether COVID-19 could aggravate the health burden posed by (D)TC or vice versa has yet to be clarified. Improved understanding and harnessing of the pathophysiological landscape of the COVID-19–(D)TC association will empower a mechanism-guided, safe, evidence-based, and risk-stratified management of (D)TC in the COVID-19 era and beyond. Conclusion: A multidisciplinary patient-centered decision-making will ensure high-quality (D)TC care for patients, with or without COVID-19.

The Intriguing Thyroid Hormones–Lung Cancer Association as Exemplification of the Thyroid Hormones–Cancer Association: Three Decades of Evolving Research

“…In fact, there is ample epidemiological evidence concerning the COVID-19–thyroid association and the COVID-19–cancer association, while the relevant molecular mechanisms are currently under research. The authors of the present review have extensively discussed these topics elsewhere [ 158 ]. Briefly, the molecular background of the COVID-19–thyroid association includes a direct injury of the thyroid gland through inflammatory and immunological reactions and/or damage of the HPT axis either directly or indirectly.…”

The Clinical Relevance of Hypothyroidism in Patients with Solid Non-Thyroid Cancer: A Tantalizing Conundrum

“…The special causes of hypothyroidism in patients with solid non-thyroid cancer constitute an extensive issue beyond the scope of the present review. Briefly, such causes include radiotherapy, certain anticancer drugs (e.g., high dose interleukin 2 (HD IL-2), interferon type α (IFN-α), bexarotene, tyrosine kinase inhibitors (TKI), and immune checkpoint inhibitors (ICPi), mainly the anti-PD-1/PDL-1 monoclonal antibodies (mAbs)) [ 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 ]). The high prevalence of iodine-based contrast media (ICM)-induced hypothyroidism, reaching 15% in areas with high iodine intake [ 34 ], is a concerning issue in cancer patients who undergo numerous radiological examinations with ICM.…”

“…First, in the case of anticancer treatment-related hypothyroidism, it is critical to decide whether a cessation of the offending anticancer treatment is needed. Especially for ICPi-induced hypothyroidism, the decision-making is individualized depending on the severity of the hypothyroidism [ 33 ]. Second, the presumed, yet dual, impact of L-T4 on cancer risk raises questions about the safety of L-T4 for cancer patients.…”

“…The landscape of THs actions is further complicated by the emerging role of THs metabolites in cancer [ 16 , 17 ]. The clinical relevance of hypothyroidism in patients with solid non-thyroid cancer shares many complex characteristics with hypothyroidism in the general population [ 18 , 19 ], but the former is even more complicated than the latter due to distinct issues arising from the hypothyroidism–cancer association [ 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 ].…”

“…A notable number of cancer patients are expected to confront the hypothyroidism–cancer association, given that hypothyroidism constitutes a common adverse effect of innovative anticancer treatments [ 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 ] and diagnostic procedures using iodinated contrast media [ 34 ], which have, currently, revolutionized the standard of cancer care. Hopefully, hypothyroidism that is induced by the administration of iodinated contrast media is not general and is transient, being attributed to the suppression of THs synthesis via the Wolff–Chaikoff mechanism—an effect that lasts only a few weeks.…”