A Clinical Study Of Influence On Thyroid Function After Radiotherapy Of Head And Neck Cancer

Radiotherapy is one of the most important treatment of head and neck cancer. With the development of radiotherapy, especially three dimensional conformal radiotherapy (3D-CRT) and intensity-modulated radiotherapy (IMRT), the prognosis of head and neck cancer compare with previous have made great strides. Radiotherapy target of the head and neck cancer patients include thyroid and/or the pituitary gland. After radiotherapy whether have thyroid function change and the variation trend has attracted foreign and domestic scholars'attention.According to some literature reports: after the radiotherapy FT₃ and FT₄ of the patients of head and neck cancer decline and the variation of TSH number value, three group of scholars have different opinions. The first scholars group considered that it increases; the second group thought it is changeless and the third thought it decrease.This study is mainly research on the changes of thyroid function of the patient with head and neck cancer after radiotherapy and to know if it will happen hypothyroidism after radiotherapy and will occur thyroidism at how much cumulative dose, we also want to know it is which type of hypothyroidism.We want to monitor the 50 cases of patients who were hospitalized from 2008 to 2010 with head and neck cancer of FT₃, FT₄, TSH number value. These 50 patients had no thyroid and endocrine disease. And before the treatment monitoring thyroid function all were normal and no surgically history. The treatment target of these patients includes thyroid and pituitary. At 0cGy, 3600cGy, 4600cGy, 5600cGy, 6600cGy we adopted chemiluminescence method to detect the three above-mentioned. FT₃, FT₄, TSH are decline but FT₃,FT₄ have statistical signification at 4600cGy this spots and TSH has statistical signification at 5600cGy(P<0.05). During the treatment FT₃ and FT₄ these two indexes are decline but also are within the normal limit, and TSH of three patients drop to below the normal limit.From the results of this study, we can find that the patients whose irradiated target including thyroid and pituitary with head and neck cancer will occur hypothyroidism. According to the index dose can be found that FT₃,FT₄ have statistical signification at 4600cGy,but FT₃, FT₄, TSH all have statistical signification at 5600cGy. Thyroid function has been influenced between 4600cGy and 5600cGy. Pituitary function has been influenced at 5600cGy. It shows that 5600cGy is critical point. Before it we consider radiotherapy influence thyroid function and after it both thyroid function and pituitary function be influenced. Before 5600cGy, if hypothyroidism were happened we consider primary hypothyroidism, after it, we also consider hypothalamic hypothyroidism, and they are concurrence. This for our clinical work has certain directive significance. So if we are doing the treatment plan we must pay attention to the protection of the two organs. Before 5600cGy we pay much attention to thyroid and after 5600cGy we take care the two organs to prevent primary or hypothalamic hypothyroidism.Because of the lack of specific clinical symptoms, hypothyroidism diagnosed all depends on laboratory examinations. So the advice we can give to the doctors is to periodically monitor thyroid function of patients suffering of head and neck cancer in radiation, in order to detect earlier the variation of thyroid function, and give the hormone replacement therapy.This paper is one of the study's complement,as a reference in the later retrospective statistics.