1. What is a thyroid nodule?
A mass in the thyroid gland is collectively called a thyroid nodule and is the most common type of thyroid condition. Nodules are found by palpation in about 3-7% of cases, while ultrasonography can reveal nodules in 20-76% of subjects. They are more common in women than in men (4:1) and more common in middle-aged and older people than in adolescents, so thyroid nodules are found quite often in women after middle age by ultrasonography. In fact, a nodule is just a morphological description of a thyroid swelling caused by a tumor, cyst, inflammatory mass or other disease. Some benign nodules grow faster and resemble malignant tumors, while some malignant tumors grow slowly and resemble benign nodules. Therefore, the nature of thyroid nodules cannot be determined by physical examination or ultrasonography alone, but also by medical history, physical examination, laboratory tests, and even pathological examination. Of course, objectively speaking, the vast majority of thyroid nodules are benign, with malignancy accounting for only 5%. And even malignant thyroid nodules are much less aggressive than lung cancer. Therefore, once a nodule is found, there is no need to panic, and you should not be rash.
2. Why do thyroid nodules grow? The etiology of thyroid nodules is complex and is currently believed to be related to radiation exposure, autoimmunity, genetics, iodine intake and other factors. A history of radiation exposure is an important causative factor for thyroid cancer. Individuals who received radiation doses of 10 to 1000 rad during childhood have a higher incidence of thyroid cancer. Patients with autoimmune thyroiditis are prone to develop thyroid nodules. There is no evidence that other thyroid cancers are hereditary except for familial medullary carcinoma, and only about 7% of patients with papillary thyroid cancer may have a familial predisposition. Severe iodine deficiency can cause endemic goiter, but excessive iodine intake can also cause a variety of thyroid disorders, such as abnormal thyroid function and thyroid nodules.
3. Can thyroid nodules affect health?
Whether a thyroid nodule affects your health depends on the nature of the nodule’s pathology, size, growth pattern and function. The pathological nature, in short, is often referred to as benign or malignant, but of course this is a broad classification, and there are many subcategories within each broad category; in general, malignant nodules can be dangerous to our health, while benign nodules can cause some discomfort at best. Inflammatory nodules, such as subacute thyroiditis, may cause fever and neck pain; if the nodule is too large or invasive, it may compress the esophagus, trachea, and nerves, resulting in difficulty swallowing, choking, difficulty breathing, and hoarseness; if the nodule is able to secrete thyroid hormones on its own, it may cause symptoms of hyperthyroidism such as panic, fever, excessive sweating, hunger, and weight loss; if If hypothyroidism is combined with the nodule, the symptoms may include chills, swelling, memory loss, etc. If the nodule is necrotic and bleeding, the neck lump will suddenly increase in size and may cause pain. Of course, the majority of benign nodules do not cause any subjective discomfort and can live with you peacefully.
4. How can I detect a thyroid nodule?
Palpation of the neck during a physical examination is the main method of detecting thyroid nodules, and it is also the easiest and most convenient method. However, there are limitations because palpation can only detect large or superficial nodules, and the experience of the examiner can have an impact on the detection rate of nodules. Ultrasound not only provides important information about the size, texture, borders, calcification and blood flow signals of nodules, but it is also non-invasive, quick and inexpensive. CT and MRI are not superior to ultrasound in the diagnosis of thyroid nodules and are therefore not routinely used, but only when the nodule is located behind the sternum and cannot be detected by transcervical ultrasound, or when the relationship between the nodule and the surrounding tissue needs to be understood. Because the thyroid gland contains iodine and has a natural contrast advantage with surrounding tissues, clear images can usually be obtained with CT plain scan; because iodine-containing contrast agents may affect thyroid function, enhanced scans should be avoided in patients with nodules with combined abnormal thyroid function and used only when necessary.
5. What should I do if a thyroid nodule is found?
A thyroid nodule should be seen by an endocrinologist when it is found. A detailed history will help to determine the nature of the nodule. Nodules with symptoms of hyperthyroidism may be high-functioning adenomas, or early stages of subacute thyroiditis and Hashimoto’s thyroiditis; nodules with hypothyroidism, usually late stages of subacute thyroiditis and Hashimoto’s thyroiditis, or xylogranuloma; nodules with a history of childhood radiation therapy to the neck, or nodules in children from non-thyroid endemic areas, have a higher chance of being malignant; nodules with a family history of thyroid cancer have a higher rate of malignancy; nodules that have been present for years The possibility of malignancy should be considered when nodules that have been present for many years increase in size painlessly and significantly in a short period of time. After nodules are found, some necessary biochemical tests should be done, including thyroid function, autoantibodies and tumor markers. Most patients with nodules have normal thyroid function, and those with TSH abnormalities are less likely to have malignant nodules. Thyroid-specific antibodies TRAb, TPOAb, and TGAb are meaningful for the diagnosis of thyroiditis and have no special significance for the differentiation of benign and malignant. Calcitonin and carcinoembryonic antigen are elevated in medullary thyroid carcinoma. High-resolution ultrasonography is highly sensitive in detecting thyroid nodules, but is not as specific in determining benign or malignant.
6. In which cases should fine-needle aspiration cytology be performed?
The best way to distinguish benign or malignant thyroid nodules is currently ultrasound-guided fine-needle aspiration cytology (FNA) of thyroid nodules, for reasons of economy and benefit. FNA is mainly performed on nodules ≥1 cm in diameter and nodules that are not very large but have the following conditions: (1) previous radiation therapy to the head and neck; (2) family history of medullary thyroid carcinoma or multiple endocrine tumors type II; (3) age <20 or >70 years; (4) male; (5) fast-growing nodules; (6) hard nodules with indistinct margins; (7) fixed nodules; and (8) cervical lymphoma. fixed; ⑧ with enlarged cervical lymph nodes; ⑨ with symptoms such as hoarseness, cough, dysphagia and dyspnea.
7. “Cold nodules” is not synonymous with thyroid cancer
Most of the thyroid malignant tumors have a reduced uptake of 131 iodine, and the result of isotope scan (ECT) is “cold nodules”. However, the term “cold nodules” is not synonymous with malignancy; “cold” simply means that iodine uptake is significantly reduced. There are many reasons for the reduced iodine uptake of nodules, such as thyroid cysts, where the cystic nodules are filled with cystic fluid and there are very few glandular epithelial cells, so ECT will naturally appear as “cold nodules”. In addition, the preparation before ECT can also affect the test results. If you have eaten seafood (such as kelp, jellyfish, nori, moss sticks, etc.), used iodine, or taken medications such as eugenol and thyroid tablets within two months before the test, or eaten sea crabs and shellfish within two weeks, or sea fish, shrimp, or sea snails within one week, the absorption of isotope iodine will be affected, resulting in a “cold nodule” result. The result is “cold nodules”. According to statistics, only about 8% of all “cold nodules” are pathologically confirmed as malignant tumors, and more than 90% of “cold nodules” are benign, so there is no need to see “cold nodules”. Therefore, there is no need to be alarmed by “cold nodules”.
Isotope scan can also observe the location of retrosternal goiter and ectopic thyroid gland, track the metastases of thyroid cancer, determine the recurrence of thyroid cancer, and identify whether the neck mass originates from the thyroid gland or its relationship with the thyroid gland, which is useful for the diagnosis of thyroid nodules.
8. Will fine needle aspiration of thyroid nodules cause the tumor to spread?
No. Needle aspiration of thyroid nodules is performed with a very fine needle, and the thyroid tissue is aspirated for cytological examination. It is the gold standard for preoperative differentiation of benign and malignant thyroid nodules and is also an effective method for the diagnosis and differential diagnosis of many thyroid diseases. Fine needle aspiration is used to extract the material, and the aspirated tissue is hidden in the needle core due to negative suction, so that it will not leak out and contaminate other levels of tissue, and there is no risk of tumor spread. So far, no tumor implantation in the needle tract has been reported in the use of fine needle aspiration for thyroid nodules, so there is no need to worry about the spread of tumor caused by aspiration.
9. What treatments are available for benign thyroid nodules?
Not all thyroid nodules need to be treated. The tests mentioned earlier can help the doctor to distinguish between nodules that need treatment and those that do not require intervention and should be followed up only. There are several treatment options: medications, surgery, isotopes, and anhydrous alcohol injections. Of course, the treatment plan is chosen on a case-by-case basis and is sometimes adjusted, for example, patients who are initially followed only periodically may require surgery due to rapid nodule growth or calcification. The final treatment plan is developed after weighing the pros and cons and after thorough communication with the patient.
10. What about hyperthyroidism or hypothyroidism with nodules?
It is not uncommon for thyroid nodules to be accompanied by abnormal thyroid function. Some are a direct result of the nodule, as if it were a mother-child relationship: e.g. high-functioning adenoma, late stage of nodular goiter; but more often it is just a concomitant state, as if it were a sister relationship: e.g. hypothyroidism due to Hashimoto’s thyroiditis, or Graves’ hyperthyroidism with a nodule. In the case of a mother-child relationship, if the nodules are removed, the functional abnormalities are naturally corrected. In the case of high-functioning adenomas, both surgery and isotope therapy can provide a one-two punch of treatment. If they are sisters, then they need to be treated separately. Patients with Hashimoto-induced hypothyroidism need to be treated with thyroid hormones to correct the hypothyroidism, while patients with hyperthyroidism should first control the hyperthyroidism with antithyroid drugs, and then have surgery if the nodule needs surgery after the hyperthyroidism is controlled.
11. Which nodules are suitable for thyrotropin suppression therapy?
In short, nodules in between surgery and follow-up are suitable for thyroxine suppression therapy. Experience has shown that thyroxine has no suppressive effect on larger nodules, so thyroxine suppressive therapy should be selected for nodules that are not large and less than 2 cm in diameter. For nodules that are not originally large but are observed to increase in size during follow-up, thyroxine suppression therapy can be used, not only as a therapeutic tool, but also to indirectly determine the nature of the nodule by observing the response of the nodule after treatment. If the nodule continues to grow during suppressive therapy, it can be used as an indirect basis for the possibility of malignancy, since direct examination such as fine needle aspiration of smaller nodules can be difficult to perform, and the indirect basis becomes more important at this time.
12. Which patients are not suitable for thyroxine suppression therapy?
Suppressive therapy for thyroid nodules requires patients to take more thyroxine than is physiologically necessary to cause artificial hyperthyroidism, which suppresses the secretion of thyrotropin (TSH) by the pituitary gland, a key hormone that can cause goiter and tumor growth. Because supraphysiologic doses of thyroid hormone can cause increased heart rate, increased myocardial oxygen consumption, and loss of bone calcium, they are not indicated for patients with pre-existing tachycardia, tachyarrhythmia, coronary artery disease, hypertension, severe diabetes, osteoporosis, insomnia, and menopausal women and elderly patients, as their pre-existing symptoms may be aggravated to varying degrees after taking the drug. TSH in patients is often not the cause of the thyroid nodule and therefore suppressive therapy is not necessary. Thyroid nodules due to pituitary TSH tumors have high TSH, but thyroxine suppressive therapy is ineffective and can exacerbate hyperthyroidism and should be treated with pituitary tumor resection or Gamma Knife.
13. Which nodules require surgery?
A case-by-case analysis is needed. Surgical treatment is recommended in the following cases: 1. for those with rapid growth, high suspicion of malignancy and confirmed malignancy by puncture; 2. for those with large nodules, symptoms of pressure and poor results of non-surgical treatment;
3. Nodules with combined hyperthyroidism.
14. What should I pay attention to in terms of diet for patients with thyroid nodules?
A case-by-case analysis is needed. First of all, the cause and classification of thyroid nodules should be clarified, and the appropriate diet should be adopted according to the different conditions of thyroid nodules. If Graves’ hyperthyroidism is accompanied by thyroid nodules, it is necessary to strictly avoid iodine diet, consume non-iodized salt and prohibit seafood such as kelp, seaweed and sea fish; if Hashimoto’s thyroiditis is accompanied by nodules, it is not necessary to strictly avoid iodine, but a large amount of food with high iodine will increase the damage of thyroid follicular cells and antibody production, which will aggravate the destruction of thyroid cells. If the nodule is a high-functioning adenoma that can secrete thyroid hormone, iodine should be strictly avoided because iodine is one of the raw materials for thyroid hormone synthesis, and iodine intake will also increase the synthesis of thyroid hormone, which will aggravate the symptoms of hyperthyroidism. If it is a non-functioning nodule, which means it has no effect on thyroid function, there is no need to avoid iodine in the diet. It is recommended to consume less food such as radish and cabbage, as current studies have found that these two foods promote the growth of thyroid nodules.
15. What are the types of thyroid cancer?
Papillary carcinoma, follicular carcinoma, undifferentiated carcinoma, medullary carcinoma, squamous carcinoma, and lymphoma.
16. What are the treatments for thyroid cancer?
The main treatment methods are surgery, endocrine therapy, radiation therapy and chemotherapy. Once thyroid cancer is diagnosed, surgery is the first treatment. After surgery, endocrine therapy is required, i.e. thyroid hormone suppression and replacement therapy, and thyroid function and thyroglobulin follow-up to prevent recurrence of thyroid cancer. For thyroid cancer with metastasis, radioactive 131 iodine ablation therapy can be used after surgery to eliminate residual thyroid tumor cells and prevent metastasis or recurrence of the tumor. Drugs for internal treatment of thyroid tumors are not commonly used in China at present.
17. Can thyroid tumors be hereditary?
At present, there is only one type of thyroid tumor with clear hereditary tendency, namely medullary thyroid carcinoma, which is a malignant tumor derived from calcitonin-secreting C cells and has a high degree of malignancy. Patients may have medullary thyroid carcinoma alone or both parathyroid adenoma and adrenal pheochromocytoma, and may have clinical manifestations of hyperparathyroidism or hypertension, the latter being called polyendocrine adenomatosis type 2. The causative gene is the RET proto-oncogene, and genetic diagnosis is now feasible, and risk stratification can be performed according to genotype to determine different treatment strategies.