Thyroid cancer is a common neck malignancy. Currently, total thyroidectomy or subtotal thyroidectomy is the main method for the treatment of thyroid cancer patients. However, some thyroid cancer may still have residual thyroid tissue after operation. Therefore, in the differentiated thyroid In the treatment of cancer, iodine 131 treatment is mainly used because iodine 131 can emit high-energy beta rays, destroying the residual tissue of thyroid cancer and achieving good therapeutic goals. However, in the treatment of iodine-131, certain salivary glands are inevitably damaged, and the patient will have dry mouth symptoms. After the same treatment with iodine-131, some patients will experience gastrointestinal reactions such as nausea and vomiting. The therapeutic efficacy of iodine-131 depends on the lesion's uptake of iodine-131, which requires an increase in serum TSH levels. All patients in this study had stopped taking thyroid hormone for 3-4 weeks before iodine 131 treatment, making serum The TSH level is greater than 30 mU/L. At this time, the patient is in hypothyroidism. People with hypothyroidism experience dry mouth, dry skin, constipation, pain, cold, poor memory, depression, and weight gain. Many studies have pointed out that some cancer treatments, such as chemotherapy and radiotherapy, also have an impact on the microbial flora. However, studies on the relationship between microecology, hypothyroidism and iodine-131 treatment, probiotics in the prevention of hypothyroidism and iodine-131 treatment The link between the effects of side effects remains unclear. Therefore, the team will conduct a correlation study between microbes and hypothyroidism, iodine-131 treatment.

Thyroid cancer is a common neck malignancy and it mainly affects thyroid follicular cells or parafollicular cells. Thyroid cancer in various tumors in the body, the ratio can reach 1.2% to 2.3%. Thyroid cancer can be divided into differentiated thyroid cancer, squamous cell carcinoma, undifferentiated carcinoma, and medullary carcinoma, among which the incidence of differentiated thyroid carcinoma is more than 90%. At present, total thyroidectomy or subtotal thyroidectomy is the main method for the treatment of thyroid cancer patients, but some thyroid cancer may still have residual thyroid tissue after operation. Therefore, in the treatment of differentiated thyroid cancer, iodine 131 is mainly used. Treatment, because iodine 131 can emit high-energy beta rays, destroying the residual tissue of thyroid cancer, to achieve good therapeutic purposes. However, due to the presence of sodium iodine symporter in salivary glands and thyroid, it is inevitable that certain salivary glands will be damaged in the treatment of iodine 131, and patients will have dry mouth symptoms. Some patients with nausea 131 will also experience nausea and vomiting. Gastrointestinal reaction. Iodine 131 treatment is divided into two steps: 1 removal of residual thyroid tissue; 2 removal of cancer lesions and metastases. The curative effect of 131I depends on the lesion's uptake of iodine-131, which requires an increase in serum TSH levels. All patients in this study had stopped taking thyroid hormone for 3 to 4 weeks before iodine-131 treatment. The TSH level is greater than 30 mU/L. At this time, the patient is in hypothyroidism. People with hypothyroidism experience dry mouth, dry skin, constipation, pain, cold, poor memory, depression, and weight gain. Many studies have pointed out that some cancer treatments, such as chemotherapy and radiotherapy, also have an impact on the microbial flora. However, studies on the relationship between microecology, hypothyroidism and iodine-131 treatment, probiotics in the prevention of hypothyroidism and iodine-131 treatment The link between the effects of side effects remains unclear. Therefore, the team will conduct a correlation study between microbes and hypothyroidism, iodine-131 treatment.

Inclusion Criteria:

• Age 18 years old, 65 years old, male and female;
• Histologically confirmed differentiated thyroid cancer;
• After total thyroidectomy, patients who have undergone 131I therapy for the second time or more after recurrence or regional lymph node metastasis after 131I treatment for the first time are required. Or after the first 131I treatment, patients with differentiated thyroid who were treated with 131I for more than 3 months.

Exclusion Criteria:

• Use of various antibiotics within three months;
• Having a history of alcoholism for more than 2 years and a history of smoking throughout the year;
• pregnancy or lactation;
• having oral, respiratory and gastrointestinal diseases;
• has a variety of metabolic diseases, such as obesity, hypertension, diabetes, stones, various liver diseases, etc.;
• having other autoimmune diseases such as rheumatoid arthritis, ankylosing spondylitis, inflammatory bowel disease, etc.;
• History of gastrointestinal surgery or other recent surgical history;
• Has a family history of genetic disease, mental illness, etc.;
• Research subjects are participating in other research topics;
• The researchers believe that other reasons are not suitable for continuing clinical trials;
• Undifferentiated thyroid cancer.