Thyroid cancer is a relatively common malignant tumor of the head and neck, accounting for about 35% of all head and neck malignancies. It is also the malignant tumor with the highest incidence in the endocrine system, and its incidence is characterized by a clear gender bias. The annual incidence rate is 3/100,000 for men worldwide, but 2 to 3 times higher for women. Thyroid cancer can occur in all age groups, but it has two peak ages, i.e. 7-10 years old and 40-65 years old. In terms of geographical distribution, some coastal areas such as Tianjin are the areas with high incidence of thyroid cancer, and the incidence rate is significantly higher than inland, and the incidence rate has been increasing significantly in recent years. Therefore, thyroid cancer has become a major disease that endangers the health of residents in coastal areas of China, especially middle-aged women.
I. First acquaintance with thyroid gland
Location of thyroid gland: The thyroid gland is located in front of the neck, below the laryngeal nodes and on both sides of the trachea, and consists of two lateral lobes and a narrow isthmus lobe in the middle. Under normal circumstances, it is not easy to feel the outline of the thyroid gland in the neck.
The role of the thyroid gland: The thyroid gland has a complex function, mainly to take in and store iodine, as well as to synthesize and secrete thyroxine. Thyroxine can promote the metabolic process of various cells in the body and enhance the physiological activities of many organs; it affects the development of fetus, growth of infants and maturation of bones, etc.
Types of thyroid cancer
Thyroid cancer is not an incurable disease, most of them can be cured. There are four main types of thyroid cancer, and the malignancy and healing of each type are different.
Papillary carcinoma: It accounts for the majority of thyroid cancer and can be treated satisfactorily with regular and thorough surgical treatment. However, papillary carcinoma includes many different variants, and some variants such as columnar cell type and high cell type have relatively poor prognosis and are prone to lymph node metastasis.
2.Follicular carcinoma: it is prone to blood metastasis. However, as long as the treatment is timely and the surgery is thorough, the effect is still quite satisfactory. However, the treatment effect of late stage is not so satisfactory.
3.Medullary carcinoma: It is highly malignant and prone to bilateral development. A considerable proportion of patients can survive for a long time with regular and timely surgical treatment.
4.Undifferentiated carcinoma: It is the most malignant among thyroid cancer and develops very fast. When patients come to the hospital, most of them are in advanced stage and the treatment is very poor, and they often die within a year. Fortunately, only a small number of patients have this type of cancer.
High incidence factors of thyroid cancer
1.Ionizing radiation: Radiation cancer is related to the mode of radiation. Until now, cancer caused by radiation mostly occurs after external X-ray irradiation. For example, Japanese atomic bomb explosion and Chernobyl nuclear power plant accident both caused a significant increase in the incidence of thyroid tumor. Furthermore, it is important to note that the risk of thyroid cancer decreases with increasing age of radiation exposure, i.e., the risk is higher in young children than in adults. The younger the irradiated pediatrician, the higher the risk of developing cancer. In addition, the risk is generally higher in women than in men.
2.Iodine: Thyroid cancer is more common in iodine-deficient areas and also in coastal areas with high iodine.
3.Gender and estrogen: There is a big difference in the incidence of thyroid cancer between genders, with women being significantly more likely than men. Estrogen can affect the growth of thyroid gland, and its high level may also be one of the cancer-causing factors.
Family factors: In some thyroid cancer patients, especially medullary thyroid cancer, it is common to see more than one member of a family suffering from medullary thyroid cancer at the same time.
Common symptoms of thyroid cancer
1. the appearance of a mostly painless swelling or nodule in front of the neck.
2, sudden appearance of hoarseness in the voice.
3.The appearance of enlarged lymph nodes in the neck.
4. difficulty in swallowing and inspiration.
It should be emphasized that the above symptoms alone cannot diagnose thyroid cancer, and specific analysis and differentiation are needed to determine whether it is cancer or not. At present, the proportion of malignant tumor in a solitary thyroid swelling is about 10-25%, and nearly 1/3 of the patients admitted to hospital are thyroid cancer, so the pre-cervical swelling should be highly noticed by patients.
V. Examination and diagnosis of thyroid cancer
In clinical practice, it is found that most patients with thyroid tumor are diagnosed with thyroid nodules as the main symptom. Therefore, it is especially important to determine the nature of thyroid cancer through various examinations for appropriate treatment.
1.B ultrasound
Ultrasound is an important routine examination tool, which can clarify the size, boundary and nature of thyroid tumor, as well as determine the benignity and malignancy of nodules and whether there is metastasis.
2.CT
It can clearly show the scope of lesions, especially the scope of lesions in the thorax and the relationship with adjacent large blood vessels, and provide a reliable basis for the formulation of treatment plan.
3.Histopathological examination of biopsy
For resectable thyroid masses, surgery can be performed without preoperative biopsy. If malignancy is suspected, a rapid intraoperative frozen pathological examination can be performed to clarify the benignity and malignancy. For huge masses requiring a clear diagnosis, needle aspiration biopsy is feasible if the patient has no obvious aspiration difficulties.
4.Tumor markers
Patients with medullary thyroid cancer often have abnormally elevated serum calcitonin (CT) levels. Therefore, CT can be used as a tumor marker for medullary thyroid cancer to help clarify the diagnosis and assess the postoperative outcome. In addition, serum carcinoembryonic antigen CEA is also elevated to some extent in some patients with medullary thyroid cancer.
5.PET/CT
PET/CT is the most advanced means of tumor diagnosis, as it can diagnose the disease at the molecular level, while CT can display the precise anatomical structure of the human body, which is a precise organic fusion of functional and anatomical images, and can provide a comprehensive understanding of potential regional lymph nodes and distant metastases at one time, and improve the staging, benign and malignant differentiation of primary foci and postoperative evaluation. Our hospital has taken the lead in applying PET/CT in the diagnosis of thyroid cancer in China, and achieved very good results.
Prevention of thyroid cancer
Scientific and reasonable living and eating habits can help you keep away from thyroid cancer.
1.Avoid exposure to radiation.
2. timely and active treatment of thyroid nodules.
3. for residents in coastal areas, do not consume too much food with high iodine content and deliberate iodine supplementation.
4.Avoid contact with known carcinogenic substances.
5.People with family history should pay attention to regular examination.
Get out of the misunderstanding of thyroid cancer diagnosis
1.Thyroid cancer and great neck disease
Great neck disease is a benign enlargement of the thyroid gland, forming a lump in front of the neck or on both sides of the trachea, which gradually grows, medically known as nodular goiter, mostly occurring in residents of mountainous areas, the so-called endemic goiter. However, in a few patients, the sudden growth of the swelling accelerates, which is a sign of malignant change, that is, it may turn from benign to malignant cancer, so you need to ask your doctor for an examination in time.
2.The different significance of multiple nodules and single nodules in thyroid gland
Multiple thyroid nodules, often called nodular goiter, is a benign lesion, with a few coexisting cancers. In contrast, a solitary thyroid nodule is generally a benign adenoma with a malignancy rate of 10-20%. This is especially true for small nodules less than two centimeters in diameter, which are often underestimated because the patient is not in any discomfort and are difficult for the doctor to feel with his hands. Therefore, single nodules in the thyroid gland should be taken seriously enough to take active treatment.
3.A thyroid nodule that has been growing for more than 10 years is not always a benign tumor
Because most thyroid cancers are low grade malignant and grow slowly, the average disease duration (the time between the discovery of a lump and the patient’s visit to the doctor) is 5-6 years, and the longest can be 30 years. This is the difference between thyroid cancer (mainly papillary thyroid cancer and follicular cancer) and other cancers. Therefore, it is difficult to say that a thyroid lump that has existed for more than 10 years is not cancer.
4.What is the cause of sudden onset of hoarseness in a goiter that has existed for many years?
A goiter that has existed for many years and has a hoarse voice (sudden or progressive) is mostly due to the fact that this mass is malignant and grows infiltrating into the surrounding area, involving a nerve that innervates articulation (the laryngeal recurrent nerve) that passes through it, causing a hoarse voice. Most of the hoarseness caused by thyroid masses is persistent and worsens continuously. Once this happens, you should go to a specialized oncology hospital for examination in time.
Treatment of thyroid cancer
1. Standardized surgical treatment for thyroid cancer
Surgery is the first and most effective treatment for thyroid cancer, and standardized surgery is the key to cure thyroid cancer.
Surgical treatment of primary cancer
Although most of thyroid cancers are long-lasting and slow-growing, they are still fatal diseases and should not lose the precious time for treatment. The treatment of thyroid cancer is still mainly surgical, and local treatment is the key to treatment.
Surgical treatment of metastatic cancer in cervical lymph nodes
The most common metastatic route for thyroid cancer is cervical lymph node metastasis. If cervical lymph node metastasis has already appeared clinically and the primary cancer can be resected, combined radical thyroidectomy of primary and metastatic cancer is recommended. For patients who have not yet developed cervical lymph node metastasis, treatment should be given according to the patient’s gender, age, tumor invasion and other factors.
2.Comprehensive treatment of thyroid cancer
Endocrine therapy.
Thyroxine can inhibit the secretion of thyroid stimulating hormone (TSH) in the anterior pituitary gland, thus inhibiting the proliferation of thyroid tissue and the growth of cancerous tissue. Therefore, patients take oral eugenol or thyroxine after surgery for the prevention of recurrence and treatment of advanced thyroid cancer. The dose is appropriate to reduce TSH to below 0,1, preferably below 0,05, while T3 and T4 basically do not exceed the upper limit of normal value.
Iodine 131 therapy.
Thyroid cancer is less sensitive to radiotherapy and chemotherapy. Papillary and follicular carcinoma are usually treated with internal irradiation using iodine 131.
3.Treatment of advanced and recurrent thyroid
Due to delayed treatment or irregular initial treatment, it is easy to cause local recurrence of thyroid malignant tumor or invasion of adjacent important organs, which brings great difficulties to treatment to a certain extent.
The thyroid gland is close to the trachea, esophagus, larynx and the carotid artery leading to the brain, so once the thyroid tumor invades the above important organs, it is considered as advanced thyroid cancer, which is very difficult to treat. However, since most of the thyroid cancers are less malignant, once diagnosed with advanced thyroid cancer, patients and their family members should not give up the treatment because of pessimism and disappointment, but should actively cooperate with the doctor and get correct and timely treatment. At present, the treatment of advanced thyroid cancer is still mainly based on surgery, which includes the removal of tumor and the adjacent organs invaded, as well as the repair and reconstruction of function. With the development and maturity of surgical techniques, most advanced tumors can be completely removed.