It’s hard enough having to go through radiation and other treatments for cancers in the head and neck area, but one of the lesser-known side effects of that radiation can be hypothyroidism.

A study recently published in an Indian medical journal looked at the prevalence of subclinical (borderline, low-level) and clinical (overt) hypothyroidism among head and neck cancer patients who received radiation to the neck. The study looked at a group of patients who had radiation to the head and/or neck area, and their thyroid values (in this case, only Thyroid Stimulating Hormone (TSH) and Thyroxine (T4) were measured, at four and nine months post-radiation. What they found was that around 11% of the patients had subclinical hypothyroidism, and a total of 42% of the patients developed radiation-induced hypothyroidism. The researchers concluded that hypothyroidism is an under-recognized complication of external radiation to the head/neck, in particular at doses of 40 Grays (Gy) or more.

The conclusion? The researchers recommend that thyroid function tests should be routine during follow-up of patients who have had head/neck radiation treatments.

The recommendation makes sense, but unfortunately, as many patients know, thyroid testing is often overlooked, even when there is a known risk factor, like radiation treatments, or family history. Thyroid evaluation should become part of the standard protocol for everyone who has undergone head and/or neck radiation treatments, and if you or someone you know has had this type of radiation, it’s important to request thorough thyroid testing from your physician.

Source: Srikantia N, et. al. “How common is hypothyroidism after external radiotherapy to neck in head and neck cancer patients?,” Indian J Med Paediatr Oncol. 2011 Jul;32(3):143-8. Online