So far, the etiology of thyroid cancer is not clear. In clinical practice, it is believed that the pathogenesis may be related to the follow
So far, the etiology of thyroid cancer is not clear. In clinical practice, it is believed that the pathogenesis may be related to the following factors.
1 iodine and thyroid cancer
Generally, iodine deficiency causes endemic goiter, thyroid hormone synthesis, thyroid stimulating hormone (TSH) levels, stimulate the thyroid follicular hypertrophy, the incidence of thyroid cancer increased, but more for follicular thyroid carcinoma. In the area of endemic goiter, papillary thyroid carcinoma accounts for 85% of the well differentiated thyroid cancer.
2 radiation and thyroid cancer
With X-ray irradiation in mice can induce animal thyroid, thyroid carcinoma; on the other hand, the thyroid destruction not caused by thyroid hormone, thyroid stimulating hormone (TSH) secretion can promote the development of thyroid cancer cells. The baby had received mediastinal thymic enlargement or neck radiotherapy in children especially prone to thyroid cancer, this is because children and adolescents cell proliferation, radiation is a kind of additional stimulus, to promote the formation of the tumor. The incidence of thyroid cancer has increased in Nagasaki and Hiroshima after the atomic bomb.
3 thyroid stimulating hormone and thyroid carcinoma
The signal transduction pathway of TSH mediated by cAMP regulates thyroid follicular cell growth may occur in thyroid cancer, serum TSH level increased, induced nodular goiter, given mutagen and TSH stimulation can induce the thyroid follicular carcinoma. Clinical studies have shown that TSH inhibition plays an important role in the treatment of differentiated thyroid cancer after surgery, but whether TSH stimulation is a pathogenic factor of thyroid cancer remains to be confirmed.
4 the role of sex hormones and thyroid cancer
The relationship between sex hormones and thyroid cancer is well received in women with well differentiated thyroid cancer. Clinical, usually adolescent tumors are also into the National People's Congress, adolescent thyroid carcinoma cervical lymph node metastasis or distant metastasis earlier than adults, but the prognosis is better than adults, 10 women after the age of incidence increased significantly, may increase with the young people of thyroid cancer estrogen. Thyroid hormone receptors (ER) and progesterone receptor (PR) were found in thyroid tissue, and there were ER in thyroid carcinoma. But the effect of sex hormones on thyroid cancer has not yet been determined.
5 other thyroid diseases and thyroid cancer
(1) nodular goiter: the incidence of thyroid cancer in nodular goiter can be as high as 4% ~ 17%. Nodular goiter is caused by TSH in different parts of the thyroid follicular epithelial hyperplasia, papillary hyperplasia and vascular regeneration, papillary thyroid cancer may occur. With iodine deficiency areas of drinking water and food to feed mice or rats, serum TSH level increased, not only induce nodular goiter, and in which the occurrence of thyroid cancer, is a risk factor for thyroid cancer.
(2) thyroid hyperplasia are congenital hyperplastic goiter long-term without appropriate treatment reported final thyroid cancer, and timely detection of congenital hyperplastic goiter, and treated with thyroid hormone replacement therapy, eliminate long-term stimulation of TSH is very important.
(3) thyroid adenoma: some people think that the incidence of thyroid cancer is related to the solitary thyroid adenoma. If the thyroid carcinoma secondary to thyroid adenoma, its type should be based on the follicular carcinoma, but the fact is that papillary thyroid carcinoma accounted for the vast majority of thyroid cancer patients often have a history of adenoma, but to confirm the relationship between the two is very difficult.
(4) chronic lymphocytic thyroiditis (Hashimoto thyroiditis, HT): Hashimoto's disease. In recent years, more and more reports of thyroid cancer have been found in HT. The incidence of thyroid cancer is 4.3% ~ 24%, HT and thyroid cancer can be the same as the two unrelated diseases. On the other hand, focal HT may also be the body's immune response to thyroid cancer. HT may lead to thyroid follicular cell damage, reduce the secretion of thyroid hormone, feedback caused by increased TSH, TSH continuous stimulation of thyroid follicular cells, hyperplasia and canceration; may also TSH as a contributing factor, at the same time in the carcinogenesis of thyroid cancer gene expression; others think that common autoimmune thyroid carcinoma with HT background.
(5) hyperthyroidism: because of the low level of serum TSH in patients with hyperthyroidism, it is believed that thyroid cancer does not occur in patients with hyperthyroidism. But it is reported that the incidence of thyroid cancer is 2.5% ~ 9.6%. In thyroid cancer, the incidence of hyperthyroidism can reach 3.3% ~ 19%. We should pay more attention to the clinical situation of hyperthyroidism combined with thyroid cancer, and should be alert to the presence of thyroid cancer.
6 family factors and thyroid cancer
Thyroid cancer is not an independent familial syndrome, but it can be used as a part of familial syndrome or hereditary disease.