Thyroid function evaluation
cancer
CANCER
The thyroid function including thyroid stimulating hormone (TSH), free thyroxine (FT4), and free triiodothyronine (FT3) measurements were performed for all patients before radiation, at the end of radiotherapy and at an interval of 3–6 months in the first two years. Thereafter, they were followed up every 6 months from the third to the fifth year and annually afterwards. Serum TSH, FT4, and FT3 levels were measured using chemiluminescence at the Fujian provincial cancer hospital.