As people become more health conscious, more and more people are having medical checkups, and most medical checkups now include thyroid screening as a routine item. The detection rate of thyroid nodules by palpation through a doctor’s examination is 3-7%, but with the help of high-resolution ultrasound, the detection rate can be as high as 20-76%. The first epidemiological survey of thyroid disease in urban communities in China showed that the prevalence of thyroid nodules was 18.6%, which means that nearly 1 in 5 people have thyroid nodules. As the people do not know much about thyroid nodules, many people are overly nervous and worried after finding thyroid nodules during medical checkups, and blindly seek medical help. Such blind treatment not only increases the financial burden of patients and wastes medical resources, but more importantly, it also affects the health of patients.
A thyroid nodule is a mass of one or more abnormal tissue structures in the thyroid gland caused by various reasons. Thyroid cancer accounts for only 5-15% of thyroid nodules. In other words, most thyroid nodules are benign and “good”.
Further tests are needed after the nodules are found.
1. Laboratory tests.
All patients with thyroid nodules should be tested for serum TSH levels.
2. Ultrasonography of the thyroid.
All patients with thyroid nodules should have a neck ultrasound. Neck ultrasound can confirm the existence of “thyroid nodules”, determine the size, number, location, texture (solid or cystic), shape, border, envelope, calcification, blood supply and relationship with surrounding tissues, and evaluate the presence of lymph nodes and their size, shape and structural characteristics in the neck area. The nodules are then evaluated for benignity and malignancy (see the following article: “Ultrasound identification of benign and malignant thyroid nodules”).
3. Fine needle aspiration biopsy (FNA).
FNAB is the most sensitive and specific method for preoperative evaluation of benign and malignant thyroid nodules. 83% sensitivity, 92% specificity, 75% positive prediction rate, 5% false negative rate and 5% false positive rate for FNA diagnosis of thyroid cancer.
Preoperative FNA testing can help reduce unnecessary thyroid nodule surgery and help determine the appropriate surgical plan. However, it is important to note that FNA cannot distinguish follicular carcinoma of the thyroid from follicular cell adenoma.
FNA can be considered for any thyroid nodule >1 cm in diameter. However, FNA is not routinely performed in the following cases.
(1) “hot nodules” with autonomic uptake as confirmed by thyroid nuclide imaging.
(2) Ultrasound suggests a purely cystic nodule.
(3) nodules that are highly suspicious of malignancy on the basis of ultrasound images. FNA is not routinely recommended for thyroid nodules <1 cm in diameter.
However, ultrasound-guided FNA may be considered in the following cases.
(1) Ultrasound suggests a nodule with signs of malignancy.
(2) With abnormal ultrasound images of the cervical lymph nodes.
(3) History of radiation exposure to the neck or radiation contamination during childhood.
(4) History or family history of thyroid cancer or thyroid cancer syndrome.
(5) Positive 18F-FDG PET imaging.
(6) Abnormally elevated serum Ct level.
4. Thyroid nuclear imaging.
In single (or multiple) nodules >1 cm in diameter with decreased serum TSH, thyroid 131I or 99mTc nuclide imaging can determine whether the nodule has autonomic uptake (“hot nodules”). The vast majority of “hot nodules” are benign and usually do not require fine needle aspiration biopsy.
CT, MRI and PET-CT are not recommended as routine tests for the evaluation of thyroid nodules.
Treatment
1. Most benign thyroid nodules do not require treatment.
Most benign thyroid nodules require only regular follow-up and no specific treatment. In a few cases, surgical treatment, TSH suppression therapy, 131I therapy, or other treatments are available. Non-surgical methods are not recommended for the routine treatment of benign thyroid nodules, including TSH suppression therapy, 131I therapy, anhydrous alcohol injection (PEI), percutaneous laser ablation (PLA), and radiofrequency ablation (RFA).
2. Surgical treatment should be performed if the following conditions occur.
(1) The presence of local pressure symptoms clearly associated with the nodule.
(2) Combined with hyperthyroidism, where medical treatment is ineffective.
(3) The mass is located in the posterior sternum or mediastinum.
(4) Progressive growth of the nodule with clinical consideration of malignant tendency or combined with high risk factors for thyroid cancer.
3.Surgical principles.
(1) While completely removing the thyroid nodule, try to preserve the normal thyroid tissue.
(2) Total/near-total thyroidectomy should be used with caution. The indications are that the nodules are diffusely distributed in the thyroid gland bilaterally, making it difficult to preserve more normal thyroid tissue during surgery.
(3) Intraoperative care should be taken to protect the parathyroid glands and the recurrent laryngeal nerve.
(4) Surgery carries risks and needs to be chosen carefully.
Because most thyroid nodules are benign, they do not require surgical treatment. Unnecessary surgery can cause adhesions around the trachea in the neck. Once the thyroid gland becomes malignant in the future and other cases where surgery is necessary, the next surgery will be more difficult because of the adhesions in the neck and increase the chance of surgical complications. Some patients who had surgery for nodules that did not require surgery also had complications after surgery, and some may have lifelong disabilities. For example, one patient had damage to the recurrent laryngeal nerve after surgery for a thyroid cyst in a hospital, resulting in lifelong hoarseness and difficulty in pronunciation; another patient had damage to the parathyroid glands after surgery for a thyroid nodule in a hospital, resulting in severe hypocalcemia, etc.