Like any other organ of the body, the thyroid gland can be affected by cancer. The type of malignant tumor depends on the tissue that is degenerated during the disease. The thyroid epithelial cells (thyroid cells), the follicular epithelium (where the thyroid hormones are stored) and the C-cells – cells that produce the hormone calcitonin – can be the starting point of the thyroid malignoma.
On average, about 30,000 new cases occur every year. The majority of the diseases (80%) consist of so-called follicular and papillary thyroid carcinomas, which develop from thyroid epithelial cells. The cancers just mentioned as well as the medullary thyroid carcinoma from C-cells, are differentiated tumors – they show a low degree of malignancy (degree of malignancy of the tumor) and are therefore easily treatable.
In contrast, anaplastic carcinoma, which is highly undifferentiated, grows very quickly and often does not allow a good prognosis. There are gender-specific differences depending on the original cell type. While most differentiated tumors occur three times more frequently in women, there is an equal distribution in medullary and anaplastic forms.
Causes
The causes for the development of thyroid cancer are in the majority of all cases unexplained. Ionizing radiation is believed to increase the risk of developing a differentiated carcinoma of papillary or follicular type. An iodine deficiency, which can trigger a goiter (enlargement of the thyroid gland), is apparently not a risk factor for tumor development.
However, people in iodine-rich areas tend to develop papillary thyroid cancer, which has a more favorable prognosis. The third differentiated tumor, C-cell carcinoma (medullary thyroid cancer), is due to genetic characteristics in a quarter of cases. Mutations on chromosome 11 are responsible for the tumor.
In the rest of the cases, the cause is again unknown. The anaplastic thyroid carcinoma is the most dangerous tumor due to its undifferentiated nature. It develops extremely quickly from the follicular epithelium, although no cause has been found so far.
