Researchers examined the correlation between radiation dose for head and neck cancer and subsequent thyroid dysfunction.
Radiation therapy for cancer and development of hypothyroidism: what are the predictive risks?
A study in the journal Head and Neck reviewed the records of 102 patients who received radiation therapy for head and neck cancer.
Permanent dysfunction was seen in 24.5%, with a significantly higher incidence in women. Concurrent chemotherapy increased the risk of permanent dysfunction.
There was a significant correlation between the volume of thyroid receiving greater than 50 Gy and subsequent thyroid dysfunction.
The author’s conclusions: radiotherapy-induced thyroid dysfunction is clearly dose related; the authors recommended a mean dose of less than 54.58 Gy, noting female sex and concurrent chemotherapy add to the predictive risk.