The exact cause of thyroid cancer is still inconclusive in the medical community. The recognized influencing factors are: radiation rays, deterioration of benign thyroid nodules, genetics, and diet.
1. Iodine intake
It is clinically found that iodine is the raw material for synthesizing thyroid hormones, and iodine intake has a close relationship with thyroid disease. Investigation shows that iodine intake and the incidence of thyroid disease show a “U” relationship, that is, too low or too high iodine intake can lead to thyroid disease. Iodine deficiency can lead to goiter and endemic ketosis, while iodine excess can lead to hyperthyroidism and differentiated thyroid cancer. In iodine-rich areas of the world, 5% of women and 1% of men suffer from thyroid nodules, of which 5%-15% are thyroid cancer, and there is a positive correlation between iodine excess and thyroid cancer.
2. Genetic factors
Patients with medullary thyroid cancer are often combined with pheochromocytoma, so it is presumed that the occurrence of this type of cancer may be related to chromosomal genetic factors.
3.Radiation damage
Research shows that exposure to radioactive substances in the head and neck is an important factor in causing thyroid cancer, such as electrical appliances and CT that we are exposed to in our daily life, which will increase the chance of thyroid cancer. In addition, the incidence of thyroid cancer is significantly higher in women with occupational exposure to ionizing radiation such as X-rays and CT.
4. Other thyroid lesions
Clinically, there are reports of thyroid cancer, chronic thyroiditis, nodular goiter or some toxic goiters becoming cancerous, but the relationship between these thyroid lesions and thyroid cancer is not yet certain. For example, most thyroid adenomas are of follicular type and only 2% to 5% are papillary; if thyroid cancer is transformed from adenoma, most of them should be of follicular type, but in fact, more than half of thyroid cancers are papillary cancers, so it is presumed that the incidence of thyroid adenoma carcinoma is also very small.
5.Estrogen level in women
The incidence rate of thyroid cancer is obviously higher in women than in men, and the ratio of men to women is 1:3. The higher incidence rate in women may be related to the estrogen level of women.
6.The development of medical technology
In addition, the increase of thyroid cancer incidence may also be related to the popularization of color ultrasound technology, the improvement of ultrasonographers’ examination level and the improvement of the accuracy and sensitivity of the instruments.
Prevention: Try not to be exposed to radioactive sources
It is difficult to have a clear regulation on iodine intake in the diet, only a balanced nutrition is needed. In addition, low selenium may also lead to thyroid cancer, so it is important to eat more selenium-rich foods, such as fish, shrimp, crab, sesame and garlic. Meanwhile, try not to contact with radioactive sources and be more cautious when doing radioactive treatment.
Diagnosis and treatment: Surgery is the first choice
Experts say that not all cancers are incurable. Thyroid cancer is the mildest of all malignant tumors. It is not dangerous and develops slowly, and the survival rate of patients can reach over 90% in 8 years after treatment. At present, the main methods of detecting thyroid cancer in China are color ultrasound, fine needle aspiration cytology, intraoperative frozen section, CT scan, PET-CT, isotope scan, endoscopy and serological examination. Color ultrasound is the most used and mainstream detection method, with the advantages of being economical, convenient, non-invasive and with an accuracy of 85% to 90%, and is the preferred method for thyroid nodule evaluation.
So how to treat thyroid cancer after detection?
The most effective and primary treatment for thyroid cancer is surgery; however, a variety of post-operative non-surgical adjuvant treatments are highly relevant to long-term survival. Pharmacological treatment with thyroxine, which is an inhibitory therapy using the negative feedback effect of thyroxine on thyrotropin, can reduce the local recurrence rate and distant metastasis rate of patients. For some tumors that cannot be completely resected, it also has some effect of retarding tumor growth. Isotope therapy also has good efficacy for some thyroid cancers, but it needs to be done after surgery to be most effective. Because of its radioactive nature, it is recommended to be used with caution for patients who are too young. Also, the dose of isotope therapy should be controlled. Interventional treatment is now also available. It is mainly used as an adjuvant, for example, it can be intervened before surgery to create favorable conditions for surgery.
All things considered, surgery for thyroid cancer is still the most ideal choice at present, and standardized treatment makes the five-year survival rate of differentiated thyroid cancer reach over 90%. In the United States, the 20-year survival rate for differentiated thyroid cancer is 24% to 99%.