Most patients with differentiated thyroid cancer can be cured or survive with tumor for a long time and are considered as less malignant tumors. The key to treatment is to choose the appropriate surgery and postoperative treatment according to the pathological type and condition. Local external radiation radiotherapy and systemic chemotherapy have been eliminated in recent years because of their uncertain efficacy and side effects.
I. What is differentiated thyroid cancer?
Differentiated thyroid cancer refers to the pathological type of papillary carcinoma, follicular carcinoma or a mixture of the two.
Under what circumstances differentiated thyroid cancer requires radioiodine therapy
In principle, patients with a diameter of more than 1 or 5 cm or with cancer cells that have broken through the envelope or have metastasized lymph nodes in the neck are in need of radioactive iodine treatment.
What are the benefits of postoperative radioactive iodine therapy for differentiated thyroid cancer?
1.It plays an adjuvant role in treating the possible postoperative hidden cancer foci and metastases, thus reducing the incidence of recurrence and metastasis; the recurrence rate of surgery alone is about 33%, and the recurrence rate of surgery plus thyroxine replacement therapy is also about 15%, while the recurrence rate of surgery plus radioiodine therapy is less than 3%.
2. Iodine-131 scans performed after treatment can search for metastases throughout the body, facilitating early and accurate staging of the disease, adjustment of the treatment plan and and prognosis assessment of the patient.
3. It is convenient to monitor the recurrence or metastasis of thyroid cancer based on serum thyroglobulin (Tg) measurement and iodine-131 whole-body scan results in follow-up.
Can differentiated thyroid cancer without surgery be directly treated with radioactive iodine?
No, it is not possible. Because the primary site of thyroid cancer itself does not take up iodine, radioactive iodine will only work if the primary site is completely removed and the normal thyroid tissue and metastases visible to the naked eye are removed as much as possible.
V. What is the mechanism of radioactive iodine treatment for metastases of differentiated thyroid cancer?
Since more than 90% of metastatic foci of differentiated thyroid cancer ingest iodine, radioactive iodine can be like a refined missile to find cancer cells very accurately and kill them, which can achieve the effect of carpet removal.
After surgery, the doctor said that the lesion has been cut very cleanly, do we still need to do radioactive iodine treatment?
It should be said that it is impossible for even the most skillful surgeons to cut out all the lesions because some lesions are so small that they cannot be seen by naked eyes or even by CT. These invisible lesions are the source of future recurrence. Therefore, treatment with radioactive iodine is very necessary.
What should be done before iodine-131 treatment for thyroid cancer patients?
Since iodine-containing foods and thyroid hormones have an effect on the uptake of iodine-131 by the thyroid gland, thyroid hormones, iodine-containing foods and drugs should be stopped for more than 4 weeks before treatment. During the discontinuation period, patients can continue to take calcium supplements and correct symptoms such as hypocalcemia.
What tests should be done before iodine-131 treatment for thyroid cancer patients?
Before iodine-131 treatment, patients should have biochemical indicators of thyroid function such as TT3, TT4, FT3, FT4, TSH, thyroglobulin (Tg) and globulin antibody (TgAb) measurement, and if necessary, ultrasound of neck and chest X-ray or CT scan of chest, etc.
IX. Why and when to start replacement therapy after iodine-131 treatment
Most postoperative patients will have hypothyroidism due to surgical removal of most or all of the thyroid gland, and will require replacement therapy or suppressive therapy with thyroid hormone preparations, and will need to take the medication for life. Thyroid hormone suppressive therapy can usually be started three days after treatment. TSH should be controlled below 0,1 in high risk group and between 0,1-0,5 in low risk group.
X. What are the side effects of iodine-131 treatment for thyroid cancer
This treatment is generally safe and differs greatly from radiation therapy and chemotherapy for other tumors. After receiving radioactive iodine-131 treatment, there is usually only slight gastrointestinal discomfort and swelling and pain in the neck, but it usually does not cause serious toxic side effects such as vomiting, hair loss, bone marrow suppression and gonadal suppression; it usually does not cause infertility and other secondary tumors to increase in incidence.
XI. Which foods contain iodine
Foods with the highest iodine content are seafood, such as kelp, nori, fresh scallop, ark, dried shellfish, mussels, sea cucumber, jellyfish, lobster, etc.; kelp has the highest iodine content, reaching more than 2000 micrograms/kg in fresh kelp; followed by sea fish and sea shellfish (about 800 micrograms/kg).
Foods with high iodine content mentioned above should be avoided in the process of iodine-131 treatment to avoid affecting the treatment effect and leading to the failure of treatment.