Benign thyroid disorders include hyperthyroidism (commonly known as “hyperthyroidism”), simple goiter, thyroid adenoma, and nodular changes due to thyroiditis. The most important thing is that they can be “malignant”.
Hyperthyroidism (hyperthyroidism)
It is a disease caused by an overproduction of thyroid hormones. It includes the following types:
Diffuse toxic goiter (Toxic diffuse goiter, Graves’ disease, Graves’ disease)
Also known as primary hyperthyroidism, this is an autoimmune disease that is the most common cause of “hyperthyroidism”. The patient has antibodies against the thyroid gland that slowly and persistently stimulate thyroid proliferation and secretion, and it may also be a trigger for thyroid cancer.
We know that thyrotropin (thyroid stimulating hormone, TSH), secreted by the pituitary gland, is responsible for regulating thyroid cell proliferation and hormone secretion. If thyroid hormone levels decrease, TSH secretion increases.
It has been suggested that thyroid stimulating antibody (TSAb), a type of thyroid autoantibody, acts like TSH and plays an important role in the development and progression of thyroid cancer in patients with Graves’ disease; it may also stimulate angiogenesis and promote tumor development. It has also been found that patients with thyroid nodules who have a history of Graves’ disease have a higher risk of nodal carcinogenesis.
Despite this, there is no clear medical revelation of the relationship between Graves’ disease and thyroid cancer.
Nodular toxic goiter (also known as Plummer’s disease)
It is caused by thyroid nodules that secrete too much thyroid hormone, often on top of multinodular goiter.
At present, the relationship between it and thyroid cancer is unclear. The chance of patients developing thyroid cancer has been reported to be 2.5%, and statistics of 9% have also been reported.
Toxic thyroid adenoma
Also known as a hyperfunctional adenoma, the pathogenesis is unknown, and whether it is malignant has not been reported in the literature.
Nodular goiter
This is an advanced manifestation of simple goiter (commonly known as “big neck disease”). It is associated with chronic stimulation of TSH.
Insufficient iodine or abnormal metabolism in the patient leads to inadequate synthesis of thyroid hormones and increased secretion of TSH; stimulated by TSH, the thyroid gland proliferates and forms nodules.
And long-term TSH stimulation may also increase the chance of cancer. One study reported a 4% to 17% detection rate of thyroid cancer in patients who had surgery for nodular goiter.
Thyroiditis
Thyroiditis is an autoimmune disease that may be associated with the development of thyroid cancer and more closely with papillary cancer. One study examined 9287 thyroid specimens and found that 25% of patients with chronic thyroiditis had thyroid cancer, compared with 2.4% of patients without thyroiditis. It was also found that patients with Hashimoto’s thyroiditis (HT) had three times the risk of thyroid cancer in the general population.
In addition to thyroid cancer, thyroid lymphoma may occur on top of HT.
Thyroid adenoma
Whether thyroid adenoma is malignant has been controversial. It has been reported to have a high malignancy rate of 7% to 38%. Another study followed 354 patients with thyroid adenomas and found that 27 (7.6%) developed cancer.
Summary
There is no conclusive relationship between several common benign thyroid diseases and thyroid cancer, and although a “concomitant” association is sometimes found, it cannot be assumed that there is a causal relationship.
There are often no specific symptoms in the early stages of thyroid cancer, and if you have any of these thyroid conditions, it is recommended that you have an ultrasound of the neck every 6 months to a year.
Co-written by Dr. Shuwen Yang, Cancer Hospital of Fudan University