Although it is among the rare cancers, the most common cancer among endocrine cancers is thyroid cancer. Its prevalence in society is considered to be approximately 2%. Thyroid cancer is considered a benign type of cancer. When evaluated together with all thyroid cancers, the 5-year survival rate was calculated as 96.3% and the 10-year survival rate was calculated as 95.4%. Well-differentiated thyroid cancer (DTC) has a high recurrence rate, even if it has a generally benign course. Retrospective studies have reported that the 10-year recurrence rate is between 13-30%. ***Despite the perception among physicians that it is a benign cancer type, the recurrence rate within 10 years for tumors smaller than 1 cm is reported to be 5%, and for tumors between 1-2 cm it is 7%. It is also stated that the mortality rate is 2% in patients with thyroid cancer smaller than 1 cm and 1.6% in patients with thyroid cancer between 1-2 cm. For this reason, due care and attention should be paid to the treatment and monitoring of thyroid cancer.
Radioactive iodine therapy (RAI), popularly known as "atomic therapy", was applied by Seidlin in 1946 in the treatment of thyroid cancer. has been made. The rate of RAI use in thyroid cancer increased from 6.1% in the 1970s to 48.7% in 2006. As can be seen, RAI treatment has an important place in the treatment of thyroid cancer. RAI treatment is performed following total thyroidectomy surgery for thyroid cancer. Its purpose; It is the only treatment option to destroy the remaining thyroid tissue, thyroid cancer cells in the lymph node or other parts of the body.
RAI ablation; It is the removal of normal residual thyroid tissue with no known visible signs of cancer after surgical removal of the thyroid. RAI treatment is; It is the treatment of the main tumor residue or metastases (spread) that cannot be removed by surgical treatment. We will focus more on RAI ablation treatment.
There are 3 main reasons for RAI ablation. The first of these; Since the thyroid tissue is completely eliminated after ablation, the plasma 'Thyroglobulin - Tg' value turns into a tumor marker. Elevated Tg suggests that the cancer has recurred or metastasized. Tg, thyroid cancer It gains value because it is an important examination in the follow-up of patients. RAI ablation is needed for Tg measurement to be meaningful. The most important issue here is; Whether the patient actually had a total thyroidectomy in the first surgery and whether the serum Tg value is undetectable after the surgery. Latter; Disease staging can be done more easily with whole body scan images taken after ablation. Since normal thyroid tissue is eliminated after RAI ablation, metastatic lesions become visible and the sensitivity of I-131 (Iodine 131) whole body scintigraphy increases. Thirdly; After ablation, there may be a decrease in the recurrence of the disease and the frequency of death.
Radioactive iodine is the radioactive form of the iodine atom. This atom, known as I-131, constantly breaks down, like other radioactive substances, and emits radiation into the environment. Radioiodine given orally to the patient for treatment purposes is absorbed in a short time, like normal iodine, and accumulates in the thyroid gland, and with the radiation it emits; After the surgery, the remaining tissue in the thyroid bed is eliminated, making follow-up of the patient easier. At the same time, it reduces the recurrence of the disease and prolongs survival by detecting and treating hidden metastases.
Radioactive iodine treatment applied with appropriate patient selection following a correctly performed surgical operation causes the disease to be completely eliminated in more than 95 percent of the patients. It has been proven by research that it is eliminated. ***It is applied to patients diagnosed with papillary (PTC) and follicular carcinoma (FTC), defined as DTC, immediately after surgery. RAI is given for ablation and treatment purposes to all patient groups with a tumor diameter over 1 cm. If the tumor diameter is less than 1 cm, total thyroidectomy surgery may be sufficient. However, if the tumor diameter is less than 1 cm but metastasis is detected, there is capsule invasion (taunting), if the patient has previously received radiation, especially to the neck area, or if the cell type is bad, RAI treatment is applied.
***The most important factor affecting the success of RAI treatment is the volume of residual thyroid tissue after surgery and the I-131 retention rate of the tissue. For this reason, the type and success of the surgical intervention determines the success of RAI treatment. direct effects. The less tissue remaining, the more successful the ablation. In other words, the higher the TSH, the less residual thyroid tissue there is. At the same time, in order for the residual thyroid tissue to retain a high amount of I-131, the residual tissue must be stimulated with a high TSH level.
Reducing the amount of body iodine increases the rate at which the residual thyroid tissue retains I-131. For this reason, a diet low in iodine is recommended so as not to impair the patient's quality of life. Iodized salt, iodized cough syrups, vitamin and mineral medications containing iodine, ready-made foods such as chips, seafood, milk and dairy products, eggs, etc. It is recommended to restrict the Additionally, patients may be given diuretics (diuretics) for 4 days before RAI ablation to increase iodine excretion. Following these preparations, RAI treatment can be applied 3-4 weeks after the surgical operation. The preparation stages of RAI treatment should be planned appropriately for the patient by the nuclear medicine specialist and discussed in detail with the patient.
Before Radioactive Iodine (RAI) treatment is given, serum TSH, Thyroglobulin (Tg) of all patients should be checked. and Antitroglobulin (TgAb) values are measured. In patients whose serum TSH level does not increase; Since there is a lot of residual thyroid tissue, completion thyroidectomy (reoperation) or low dose (30 mCi) RAI must be given. The recommended dose for ablation varies between 30 mCi and 150 mCi.
RAI is given after fasting for at least 2 hours. To receive RAI treatment, the patient is taken to a specially prepared (radiation-proof, lead-lined) radioactive treatment room. RAI is given orally to the patient at the dose determined by the physician, depending on the type, size, spread of the tumor and any accompanying risk factors. A large amount of RAI is excreted from the body with urine, some with saliva, and a very small amount with sweat and feces; 50-60% of it is excreted through the urinary tract in the first 24 hours. The length of stay in the nuclear medicine service is determined by measurements taken every day. The patient is kept in the hospital until the radiation on him/her decreases from 1 meter to 5 mREM/hour. This period is generally 2-3 days, but this period may be longer or shorter depending on the dose given.
The radioactive iodine capsule given in the treatment may It has no bad taste or smell, and the patient does not feel anything during the treatment. Hair loss, which is observed in other chemotherapy methods, is not observed, and side effects related to the gastrointestinal system are very rare in this treatment.
In order to prevent the treatment given from damaging the salivary glands, it will increase the saliva secretion of the patients; Methods such as chewing lemon and gum, drinking plenty of water to reduce bladder radiation and urinating frequently are recommended. Cleaning the patient from radiation released through body secretions by taking a shower every day facilitates the removal of radiation from the body. Visitors are not allowed during the treatment and their needs are met under the supervision of medical personnel.
Since it is actually extremely difficult for a person to stay in a room alone for at least 2-3 days. ; This difficulty should be minimized thanks to the system, comfort and communication established in nuclear medicine centers.
Patients must comply with radiation safety measures in their daily lives after leaving the hospital. There are different practices in this regard in different centers. The information given to the patient and the rules the patient is asked to follow often create anxiety for the patient and his relatives. Therefore, patients; When providing information, one should be careful and avoid unnecessary and frightening statements. Since the only competent and responsible person in this regard is the nuclear medicine specialist, it is ethically most appropriate for the warnings to the patient to be made by him/her. The point to remember here is; The only reason for removing the patient from the hospital is that the radiation on the patient is no longer in an amount that could be harmful to the surrounding people.
Family members and people close to the patients are protected from both external radiation caused by RAI remaining in the body and They may be exposed to radiation effects from contamination with body fluids such as urine, sweat and saliva. Therefore, patients can go home by taxi or private car after the treatment. However, they should sit at the back of the vehicle and at the furthest distance from the driver. If they have to travel by public transportation in the first week, the journey time should not exceed 2 hours. T They should sleep separately after treatment. They should keep a distance of at least one meter from people at home and at work and should not stay there for more than an hour. Especially pregnant women and children under 10 years of age should not be approached. If possible, the toilet used by others should not be used. Urination should be done while sitting, a bidet tap and toilet paper should be used when cleaning, and hands should be washed with plenty of water and soap. In the first week, disposable materials (paper or plastic plates, cutlery, etc.) can be used. Short-term visitors of a few hours can be accepted, there must be a distance of at least 2 meters between visitors. People over the age of sixty have a low risk of being affected by radiation. It is not necessary to take protective measures for adults of this age.
If there is any situation that requires urgent treatment, the physician and staff who will care for the patient should be informed that the patient has recently received RAI treatment. However, it should not be forgotten that the above recommendations are given within the framework of general rules. In reality, each patient presents a different situation and these rules can be changed for each patient. When recommending rules, the condition of the disease, the dose of RAI treatment given, and the social, economic and cultural situation of the patient and the environment in which he or she lives are taken into consideration. For this reason, the patient receiving the treatment should discuss each issue separately with his physician, get his suggestions and implement them.
After RAI ablation, whole body scintigraphies (whole body scintigraphy) of the patients are taken within 3-10 days, usually on the 7th day. TVS) is withdrawn. This approach is very important to evaluate the effectiveness of the treatment. In addition, TVS may also reveal hitherto unknown metastases.
Read: 0
