Hypothyroidism after Radiotherapy for Head and Neck Cancer Patients
In radiation therapy for head and neck cancer, thyroid is included in the irradiation field in many cases, and hypothyroidism occurs as a side effect, are known. Hypothyroidism is a common endocrine disorder in which the thyroid gland does not produce enough thyroid hormone. It can cause a number of symptoms, such as malaise, peripheral circulatory disturbance, and which leads to edema of cardiac vesicle, ascites . The diagnosis of hypothyroidism, when suspected, can be confirmed with blood tests measuring thyroid stimulatinghormone (TSH) and triiodothyronine, thyroxine levels.
The first patient was 74 years old, women. She was underwent super selective arterial injection chemotherapy for cancer of maxillary(T4aN2cM0).Eighteen months later, she was found developed pericardial effusion and cardiac dilatation by computed tomography, and abnormal value of thyroid hormone was detected. Thyroid stimulation hormone (TSH) 235.7 μIU/ml, and free thiiodothyronine (fT3) 1.3 pg/ml, low free thyroxine(fT4) 0.4 ng/ml.
The second patient was 51 years old, man. He was underwent partial resection of maxilla, radical neck dissection for cancr of maxillary(T1N2bM0). Radiation of the neck was carried out postoperatively.Sixteen months later, he was found developed pericardial effusion by computed tomography, and edema of the face, abnormal value of thyroid hormone was detected. Thyroid stimulation hormone (TSH) 88.09 μIU/ml, and free triiodothyronine (fT3) 0.35 pg/ml, low free thyroxine(fT4) 0.06 ng/ml.
The third of patient was 68 years old, man. He was underwent super selective arterial injection chemotherapy for cancer of the oral floor/cervical lymph node metastases (pT0N2cM0). Seventeen months later, general malaise, abnormal value of thyroid hormone was detected, Thyroid stimulation hormone (TSH) 69.08 μIU/ml, and free triiodothyronine (fT3) 2.50 pg/ml, low free thyroxine(fT4) 0.77 ng/ml.
We consider that thyroid function should be evaluated before and after radiation in patients who have received neck radiotherapy.
Reference
Mercado G et al : Hypothyroydism–A frequent event after radiotherapy and after radiotherapy with chemotherapy for patients with head and neck carcinoma-. Cancer 92 : 2892-2897,2001.
Aich RK et al : Iatrogenc hypothyroidism – A consequence of external beam radiotherapy to the head and neck malignancies -.J Cancer Res Ther 1 : 142-146,2005.