Why can Iodine 131 cure differentiated thyroid cancer?
Iodine is the main food for the thyroid gland. After entering the body, most of the iodine is eaten by the thyroid cells and not by other organs. Differentiated thyroid cancer (papillary and follicular) cells look very much like normal thyroid cells and also eat iodine. Iodine 131 is the same as the iodine we normally eat, except that it is radioactive. After taking iodine 131 orally, normal thyroid cells will also eat this iodine (iodine 131 is used to treat hyperthyroidism), and differentiated thyroid cancer cells will eat it, just like normal thyroid cells. Undifferentiated or non-differentiated thyroid cancer, because of the obvious mutation of cancer cells, is not like normal thyroid cells at all, they lose the ability to eat iodine and will not eat iodine, so they will not eat iodine 131, so iodine 131 has no therapeutic effect on this kind of thyroid cancer.
Why do we need iodine 131 treatment after surgical removal of differentiated thyroid cancer?
No matter how good the surgeon who performs the surgery is, there is no 100% guarantee that no normal thyroid tissue and cancer cells will remain after the surgery. If there are cancer cells remaining, the cancer may come back. Two problems may arise from the residual normal thyroid tissue. Firstly, these residual normal tissues may contain cancer cells, which can cause tumor recurrence, and at the same time, the normal tissues may also be malignant, and secondly, the residual normal thyroid cells secrete thyroglobulin, which is the same as the thyroglobulin secreted by cancer cells. tumor recurrence. In order to reduce the recurrence of differentiated thyroid cancer after surgery, it is necessary to effectively use blood thyroglobulin measurement for early detection of recurrence and postoperative iodine 131 treatment.
Of course, metastases already existed before surgery, metastases cannot be completely removed, even if the surgery removes the ones visible to the naked eye, there may be some metastases that are not visible to the naked eye, and there are also some metastases that cannot be removed by surgery, all these cases need to be treated with iodine 131.
When is iodine 131 treatment performed after surgery?
Theoretically, the earlier it is performed, the better the results. Usually, it should be done if you have not had an enhanced CT scan before surgery, if your body is basically normal, if you are not taking thyroxine medication after surgery, and if your neck surgery wound has basically healed. If you have had an enhanced CT before surgery, it should be performed only after the urinary iodine measurement has reached the standard, which may take 3 to 4 months. If you are taking thyroxine drugs such as eugenol after surgery, you should stop taking these drugs for 2~3 weeks and have a TSH of 30 or more before proceeding.
What preparations should be made before iodine 131 treatment?
1. Abstain from iodine: Abstain from iodine-rich foods, such as kelp, nori, iodized salt, seafood, etc.
2. Stop using iodine-containing drugs, such as western amiodarone, Chinese herbs, such as kombucha, seaweed, summer cucumber, cat’s melon grass, etc.
3.If you have had enhanced CT scan or topical iodine preparation before surgery, you should test urinary iodine regularly.
4.If you have taken thyroxine drugs such as eugenol after surgery, you should stop taking them for 3~4 weeks and have your TSH tested by laboratory, generally TSH is above 30 before you are suitable for treatment.
Of course, the important point should not be forgotten, the preparation cost. It is understood that the cost varies greatly from place to place, generally around 20,000 to 30,000 yuan. Those who buy with social security or medical insurance should also remember to understand the relevant policies.
What are the side effects and manifestations of iodine 131 treatment?
The symptoms that appear early after taking iodine 131 mainly include local manifestations of the neck due to radiation thyroiditis and digestive symptoms caused by radiation irritation when iodine 131 passes through the gastrointestinal tract. The former symptoms include neck pain, swelling, etc. In severe cases, breathing difficulties may occur due to swelling and compression of the trachea. The severity of the local neck manifestations is closely related to the amount of residual thyroid gland after surgery; the more residual, the more severe the manifestations may be. In clinical practice, we have observed that the higher the TSH, the less obvious these manifestations are. Most patients’ neck manifestations are not very serious, mostly appearing 3-7 days after taking the medication and usually lasting about a week. Oral corticosteroids after taking iodine 131 can prevent and reduce the symptoms. Digestive system manifestations are mostly poor appetite, nausea, vomiting, etc., which may appear 1~3 days after taking the drug, and the symptoms will gradually disappear as iodine 131 is absorbed.
Since iodine 131 can be taken up by salivary glands, it may cause damage to salivary glands, resulting in inability to secrete saliva and dryness of oral mucosa syndrome. This side effect is mostly seen in patients with multiple treatments and is rare with single treatments. This side effect can be prevented and eliminated by drinking more water and taking acidic foods regularly after taking the drug to promote saliva secretion and shorten the retention time of iodine 131 in the salivary glands.
A very small number of patients may experience taste loss and not feel the taste of food. This often occurs within a few days after taking iodine 131 and does not require treatment and returns to normal completely after a few days.
Bone marrow suppression is one of the potential side effects and manifests as a decrease in blood cells, mainly white blood cells. It is transient and can be fully recovered. Patients with extensive lung metastases may develop pulmonary fibrosis after multiple treatments.
In general, iodine 131 treatment is very safe and rarely has serious side effects that produce serious sequelae.
What should I pay attention to after taking iodine 131?
Drinking more water after taking iodine 131 is beneficial to speed up the uptake of iodine 131 by the thyroid tissue, accelerate the excretion of iodine 131 and reduce the radiation exposure of the whole body. Take vitamin C or acidic food such as sour plum regularly to promote salivary secretion, which can prevent salivary gland damage. The nuclear medicine departments where iodine 131 treatment is performed have special iodine 131 treatment wards, which generally require hospitalization for 3-7 days. After being discharged from the hospital, there is still a certain amount of radioactivity in the body, so you should avoid close contact with your family for 1 month after returning home, and you should not sleep with children or contact pregnant women. After taking Iodine 131, you should start to take Eugenol 2~3 days after taking Iodine 131 according to the doctor’s requirement. You should return to the hospital 7~10 days after taking Iodine 131 for a whole body scan and a pre-evaluation of the possible effects of the treatment based on the results of the scan. 1.5 months should be spent back in the hospital for a review and necessary laboratory tests. Return to the hospital 3 or 6 months after treatment for a review and assessment of the efficacy of the treatment.
Can I get pregnant and breastfeed after iodine 131 treatment?
Iodine 131 can enter the fetus through the placenta and can also be secreted into the breast milk through the mammary glands. We recommend that you do not become pregnant until one year after taking Iodine 131.