Acquired disorders of the thyroid following treatment for head and neck cancer

Abstract

The multimodality management of head and neck cancer routinely utilizes radiation therapy in treatment. The hypothalamus, pituitary and thyroid gland may be included within treatment fields. The incidence of human papilloma virus-associated oropharyngeal carcinoma has seen a dramatic increase over the last 3 decades. Current guidelines for the long-term aftercare assessment advocate only for thyroid-stimulating hormone levels every 6–12 months after baseline posttreatment imaging. With a growing population of younger patients with a favorable prognosis exposed to therapeutic radiation therapy, it is anticipated that incidence of thyroid-associated complications, such as hypothyroidism and thyroid cancer, could increase significantly over time. Constructing a strategy for the long-term reassessment of these patients beyond existing guidelines may be necessary.

Keywords::

• posttreatment hypopituitarism
• radiation-associated hypothyroidism
• thyroid cancer

Financial & competing interests disclosure

The author is on a speaker’s bureau for Bristol-Myers Squibb. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

No writing assistance was utilized in the production of this manuscript.

Key issues

• • Given the changing epidemiology of head and neck cancer, posttreatment assessment protocols should be re-evaluated for patients with a history of head and neck radiation and thyroid nodularity.

• • Care providers, not directly involved in cancer care, who may see patients with a distant history of prior radiation to the head and neck need to be aware of the risks for development of hypothyroidism and potential malignancy.

• • Postradiation hypothyroidism is common during the first 10 years after treatment.

• • Patients with a history of prior skull base radiation (seen with sinonasal or nasopharyngeal cancers) are at risk for the development of disorders of the hypothalamic–pituitary axis and may require provocative testing.

• • The incidence of HPV-associated oropharyngeal carcinoma has been increasing ~2% per year and will soon surpass cervical carcinoma as the most common HPV-associated malignancy.