1.What is the thyroid gland?
The thyroid gland is a butterfly-shaped gland that is connected by two wings (left and right lobes) and a middle part (isthmus) that resembles an “H” shape. The main function of the thyroid gland is to produce thyroid hormone.
2.What is thyroid hormone?
Thyroid hormones are produced by the thyroid gland and include TT3, TT4, FT3 and FT4. The thyroid gland has a strong aggregating effect on iodine, accounting for about 80% of the iodine content of the whole body. The thyroid gland takes iodine from the blood (mostly from food such as seafood, bread and salt) and uses it to produce thyroxine, which is important for human growth and development and organ function regulation, and controls the speed of human metabolism.
3.What is 131 iodine drug?
131 Iodine (131I) is a radioactive drug, an isotope of iodine, which has the same chemical properties as iodine but differs from ordinary iodine in that it emits gamma rays for imaging and beta rays for treatment, thus playing a diagnostic and therapeutic role.
4. What is meant by radioactive iodine therapy?
131 iodine only aggregates in the thyroid tissue and is not taken up by other tissues. Thyroid cancer is the most common of human endocrine tumors, the majority of which are well-differentiated malignant tumors. Differentiated thyroid cancer cells generally retain the property that normal thyroid cells can take up and utilize iodine ions. When the thyroid gland is removed, the metastatic foci of thyroid cancer have the function of taking up 131 iodine. After the patient takes a certain amount of 131 iodine (solution or capsule) orally, the residual thyroid gland and metastases can take up 131 iodine to a high degree, and the beta radiation emitted by 131 iodine can effectively remove the residual thyroid tissue and kill the tumor cells, which is called “radioactive iodine therapy”.
5.What kind of thyroid cancer patients need 131 iodine treatment?
Radiation iodine therapy is only applicable to differentiated thyroid cancer. Medullary thyroid cancer and undifferentiated thyroid cancer are not suitable for radiation iodine therapy because they do not have the function of 131 iodine uptake. The first choice of treatment for thyroid cancer is surgery, while radioactive iodine treatment is only a further treatment after surgery, and the relationship between the two is sequential. Since differentiated thyroid cancer is less malignant and has a better prognosis, there is some controversy at home and abroad about the need for 131 iodine therapy after surgery for differentiated thyroid cancer. According to the latest foreign guidelines for thyroid cancer treatment, most patients with thyroid cancer should be treated with radioactive iodine after surgical resection, but for patients with microscopic thyroid cancer without lymph node metastasis and without risk factors for recurrence, the guidelines do not recommend routine postoperative 131 iodine treatment. In addition, for patients with poor liver and kidney function, low blood count or some advanced severe thyroid cancer such as intracranial hypertension and spinal cord compression due to brain metastasis or bone metastasis, although the cancer lesion can take up and gather a certain amount of radioactive 131 iodine, 131 iodine treatment may be life-threatening, so external radiotherapy is usually required before 131 iodine treatment.
6.What are the benefits of 131 iodine therapy?
The significance of postoperative radioactive iodine therapy for thyroid cancer is that
①131 iodine can remove the tiny thyroid cancer lesions that are difficult to detect in the thyroid tissue remaining after surgery in order to reduce the recurrence and metastasis rate.
(ii) 131 iodine-systemic imaging after radioactive iodine treatment can detect new metastases that have not been detected by other imaging examinations.
③ monitoring the presence of recurrence or metastasis by measuring thyroglobulin (Tg) in blood, which is both sensitive and accurate and facilitates follow-up.
④Local or distant metastatic foci (such as lung, bone, brain, etc.) are overwhelmingly effective after repeated 131 iodine treatment, as seen in significant shrinkage of foci, reduction of symptoms and improvement of quality of life, and some patients can be cured.
7.What is the effect of 131 iodine treatment for thyroid cancer?
At present, the most effective and reliable treatment for thyroid cancer (including residual lesions and/or metastases after surgery) is 131 iodine therapy, which has been administered systematically to thousands of patients with differentiated thyroid cancer for more than 40 years, with an overall efficiency of nearly 90%. Some of these patients (especially those who are young or have mild disease, small number of metastases and small lesions) can be cured, and most of them have their disease controlled and their quality of life improved.
8. Do I need to be hospitalized for 131 iodine treatment?
131 iodine not only emits b-rays, but also g-rays. g-rays have a strong penetrating ability and can cause radiation hazards to the patient himself, the patients in the same ward, as well as to the surrounding health care workers and other normal people. Therefore, shielding isolation is required when high-dose 131 iodine treatment is administered. In addition, there is a large amount of radioactive excretion during the early stages of 131 iodine treatment, which requires a special sewage treatment system, otherwise it can seriously pollute the environment. Therefore, the entire early phase of 131 iodine treatment needs to be carried out under conditions of radiation isolation. In addition, patients may suffer from various complications while receiving high dose 131 iodine treatment. Hospitalization allows early detection and treatment to reduce the occurrence of accidents.
9. Are there many side effects of 131 iodine treatment?
Normal tissue cells of human body have different characteristics from thyroid cancer cells. Except for normal thyroid tissue cells, other normal tissue cells seldom take up and gather 131 iodine, so the radiation hazard is relatively small. In the early stage of high-dose radioactive 131 iodine treatment, patients may experience some radiation side effects (such as upper abdominal discomfort, nausea, weakness, head and neck swelling, etc.) in varying degrees, but most of them are not serious and can be tolerated by patients or can be relieved after targeted treatment. A few patients may experience side effects such as menstrual disorders, dry mouth, dry eyes and decreased blood count in the short term, which can basically recover on their own. The whole 131 iodine treatment process is relatively safe. Based on our years of experience and research data, there are generally no serious long-term side effects associated with the current 131 iodine treatment method. Occasionally, however, patients who have been treated with high doses of 131 iodine for a long period of time (in combination with other anti-tumor treatments) may experience more serious conditions such as bone marrow suppression, which are promptly identified by our medical staff and adjusted accordingly. The safety of the treatment will be further improved if the treated patients can actively cooperate with the medical staff during the treatment period and pay attention to their own radiation protection, and if the patients can care for each other.
10.How many times does 131 iodine treatment need to be given?
If the residual thyroid lesions in the patient’s body are large, or if there are more or larger metastatic lesions, multiple hospitalizations for 131 iodine treatment will be required. The interval between each 131 iodine treatment is usually 3-6 months to ensure that the patient has enough time to get some recovery and to avoid the cumulative effect of radiation hazards. However, the interval should not be too long, otherwise the potential growth of thyroid cancer lesions during the treatment interval will exceed the efficacy of treatment inhibition, and there is no limit to the number of treatments with the ultimate goal of tumor-free survival.
11.What do I need to pay attention to before 131 iodine treatment?
First of all, patients or their family members need to come to our outpatient clinic to be seen and confirmed by our doctors that they can receive 131 iodine treatment before making an appointment for hospitalization. Before hospitalization for 131 iodine treatment, the following points need to be noted.
① Surgical incisions should heal well to avoid infection and healing difficulties after radioactive iodine treatment.
(2) In order to enhance the iodine uptake capacity of the lesion and improve the treatment effect, it is necessary to stop taking “Eugenol” (a kind of thyroxine replacement therapy) and avoid iodine diet (do not use iodine-rich foods and medications, including nutritional supplements such as seafood, iodine contrast, iodine wine, etc.) for about 3 to 4 weeks.
③While waiting for admission to the hospital for treatment, patients should take care of rest and maintenance.
④In case of any change in condition or other special circumstances, you should contact our doctors in time so that the treatment can be carried out according to the new medical prescription.
⑤ Be admitted to the hospital according to the appointment time, and bring along the records of previous treatment and necessary household items for hospitalization. Follow the rules of our hospital and the special requirements of our department for admission to the hospital for treatment.
12.How long does it take to review after 131 iodine treatment?
One month after 131 iodine treatment, patients should come to our nuclear medicine department for review. On the day of review, you need to fast and register, so that you can adjust the dosage of eugenol and observe the changes of blood picture, liver and kidney function.
13.How to take Eugenol?
However, due to individual differences and the presence of risk factors for recurrence, the dose of Eugenol may vary from patient to patient, and the exact number of tablets of Eugenol should be adjusted according to the thyroid function results and the presence of risk factors as shown in the table below. Adjustments should be made based on thyroid function results and the presence of risk factors as follows.
(1) In case of cancer foci remaining during treatment, suppressive therapy is required to make TSH <0.1mU/L.
(2) After treatment, if there are no cancer foci remaining in the clinic and biochemistry, suppressive therapy is required to achieve a TSH of 0.1-0.5 mU/L for at least 5-10 years.
(3) For low-risk patients, suppressive therapy is required to achieve a TSH of 0.3-2 mU/L when no cancer is confirmed to be present after treatment.
(4) If there is no nail clearing treatment, but there is no cancer foci, and Tg cannot be measured under suppression, and the neck ultrasound is normal, suppression treatment is required to make TSH between 0.3-2mU/L.
14.Can I have children after 131 iodine treatment?
We recommend male patients to use contraception within six months and female patients to use contraception within one year after 131 iodine treatment. Female patients should follow up their thyroid function regularly after pregnancy and delivery, and seek medical consultation if there is any abnormal index.