Thyroid dysfunction as an unintended side effect of anticancer drugs

Area of Science:

• Endocrinology
• Oncology
• Pharmacology

Background:

• Anticancer drugs can cause a range of thyroid function impairments, from subtle hormone level changes to overt thyroid disease.
• The impact on thyroid function varies significantly among different classes of anticancer agents.

Purpose of the Study:

• To review the spectrum of thyroid dysfunction associated with various anticancer therapies.
• To discuss the potential mechanisms and clinical implications of drug-induced thyroid toxicity.

Main Methods:

• Literature review of studies investigating thyroid dysfunction in patients undergoing cancer treatment.
• Analysis of reported cases and clinical trial data on anticancer drug-induced thyroid effects.

Main Results:

• Cytotoxic agents affect a small proportion of patients, while hormone therapies may alter thyroid hormone-binding proteins.
• Immunomodulating drugs (interferon-α, interleukin-2) can induce autoimmune thyroid dysfunction.
• Immune checkpoint inhibitors and tyrosine kinase inhibitors are associated with thyroiditis and hypothyroidism.
• Bexarotene can cause central hypothyroidism, and some agents increase levothyroxine requirements in thyroidectomized patients.

Conclusions:

• The pathophysiology of anticancer drug-induced thyroid toxicity is not fully understood.
• Thyroid dysfunction is generally manageable, often not requiring dose reduction or discontinuation of anticancer agents.
• Further prospective trials are needed to define the prognostic relevance and optimal management of thyroid dysfunction in cancer patients.