Thyroid Dysfunction Following Management of Non-thyroid Head and Neck Cancers

Area of Science:

• Oncology
• Endocrinology
• Radiotherapy

Background:

• Head and neck cancers are prevalent in India, often treated with chemoradiation or surgery.
• Thyroid gland damage from treatment leads to hypothyroidism, which can be subclinical and overlooked.
• Hypothyroidism manifests with various clinical symptoms and impacts patient well-being.

Purpose of the Study:

• To determine the incidence of clinical and subclinical hypothyroidism in head and neck cancer patients undergoing neck radiotherapy.
• To provide evidence for the routine use of thyroid function tests during follow-up for these patients.

Main Methods:

• A prospective, non-randomized study involved 100 head and neck cancer patients receiving radiotherapy for one year.
• Thyroid stimulating hormone (TSH), T3, and T4 levels were measured at baseline, 3, and 9 months post-radiotherapy.
• Patients received a neck radiation dose exceeding 30 Gy, with 35 also receiving concurrent chemotherapy.

Main Results:

• A total of 43 patients (43%) developed radiation-induced hypothyroidism (11 subclinical, 32 clinical).
• Clinical hypothyroidism was significantly associated with radiotherapy (P=0.001), with a mean onset of 4.5 months.
• The majority of clinical hypothyroidism cases occurred in patients aged 41-50 years.

Conclusions:

• Hypothyroidism is an under-recognized complication of external neck radiation, occurring at doses as low as 30 Gy.
• Early detection and treatment of hypothyroidism prevent related complications.
• Routine thyroid function testing is recommended for all patients undergoing radiotherapy to the neck.