Brief overview
- Prognosis: Depends on cancer type and progression; poor prognosis in anaplastic form, other forms with therapy have good cure and survival rates
- Symptoms: Initially no symptoms; later hoarseness, difficulty breathing and swallowing; swollen lymph nodes; possibly swelling of neck; medullary form: Cramps, sensory disturbances, severe diarrhea.
- Causes and risk factors: Unknown in many cases; ionizing radiation, release of radioactivity, medical radiation of the neck as risks, also iodine deficiency and goiter; familial inheritance possible
- Diagnosis: medical history, palpation of neck; ultrasound; scintigraphy; x-ray, computed tomography, and magnetic resonance imaging; tissue sample and examination of abnormal structures; blood results
- Treatment: surgery (usually removal of thyroid gland), radioiodine therapy, rarely radiation, rarely chemotherapy, depending on cancer type
- Prevention: Avoid iodine deficiency, e.g. with iodized table salt; protective measures when handling ionizing radiation; iodine tablets, e.g. in case of reactor accidents.
What is thyroid cancer?
What are the different forms?
There are different cell types in the thyroid gland with different tasks. Depending on which cell type the tumor arises from and how it grows, physicians distinguish between different types of thyroid cancer. The majority of all thyroid cancers can be classified as one of the following four types:
- Papillary thyroid cancer: about 60 to 80 percent of all cases of thyroid cancer
- Follicular thyroid carcinoma: Approximately ten to 30 percent
- Medullary thyroid carcinoma (C-cell carcinoma, MTC): About five percent
- Anaplastic thyroid carcinoma: Approximately five percent
Papillary, follicular, and anaplastic thyroid carcinoma all originate from hormone-producing thyroid cells (thyrocytes): The first two tumor types (papillary and follicular thyroid carcinoma) are also referred to as “differentiated.” This is because here the cancer cells still largely resemble healthy thyrocytes. Some cells of the follicular type even still produce thyroid hormones.
In contrast, anaplastic thyroid carcinoma is “undifferentiated”: its cells have lost all resemblance to normal thyroid cells and no longer behave like them.
Papillary thyroid carcinoma
Papillary thyroid carcinoma is the most common type of thyroid cancer, accounting for up to about 80 percent. It is characterized by wart-like outgrowths (papillae). In addition, the cancer cells here spread preferentially through the lymphatic system (lymphogenic metastasis). Therefore, the lymph nodes in the neck are often affected by the cancer.
Women develop papillary thyroid carcinoma significantly more often than men.
Follicular thyroid carcinoma
Follicular thyroid carcinoma is the second most common form of thyroid cancer. In this case, vesicular (follicular) structures form in the thyroid gland. The cancer cells spread primarily through the blood (hematogenous metastasis) – often to the brain or lungs.
Follicular thyroid carcinoma also mainly affects women.
Medullary thyroid carcinoma
Medullary thyroid carcinoma (also called C-cell carcinoma), as mentioned above, does not arise from hormone-producing thyroid cells (thyrocytes), but develops from the so-called C-cells. These are very specialized and produce only the hormone calcitonin, which is very important for the regulation of phosphate and calcium balance.
This type of thyroid cancer affects men and women equally.
Anaplastic thyroid carcinoma
Anaplastic thyroid carcinoma is the rarest type of thyroid cancer and is quite different from the others. The undifferentiated tumor grows very quickly and aggressively and is therefore hardly curable – the life expectancy of those affected is very low. Women and men are equally likely to develop this form of thyroid cancer.
Nodes in the thyroid gland are rarely cancerous
Many people have nodules in the thyroid gland. In most cases, however, they are not thyroid cancer, but a benign tumor (often a thyroid adenoma). Although such a tumor also grows uncontrollably, it does not invade surrounding tissue as a malignant tumor (thyroid cancer) does.
Frequency
In general, diseases of the thyroid gland are common in Germany, Austria and Switzerland. In the vast majority of cases, however, the disease is benign. Thyroid cancer, on the other hand, is rare, and women are significantly more likely to develop thyroid carcinoma than men.
Course of the disease and prognosis
Thyroid cancer cure rates and life expectancy depend on the type of thyroid cancer present and how advanced the disease is.
Papillary thyroid carcinoma has the best prospects of cure compared to the other types of thyroid cancer. Ten years after treatment, more than 90 percent of those affected are still alive.
Follicular thyroid cancer also has a relatively good prognosis: the ten-year survival rate is about 50 to 95 percent – depending on how far the cancer has already spread to surrounding tissue.
People with medullary thyroid cancer have a somewhat worse prognosis. Here, the ten-year survival rate is about 50 percent if there have already been distant metastases. If the cancer is confined to the thyroid gland, ten-year survival rates are up to 95 percent.
Unfortunately, anaplastic thyroid carcinoma is virtually incurable according to current medical knowledge. The median survival time of those affected is only about six months after diagnosis.
It should be noted that all these figures are average values. Life expectancy in individual cases usually differs significantly from the values given here.
Aftercare for thyroid cancer
In addition, various blood values can be measured regularly that are only produced by thyroid tissue – if they can be detected again after complete removal of the thyroid, this indicates renewed tumor growth. These laboratory values are known as tumor markers. Of particular interest are calcitonin (in medullary thyroid carcinoma) and thyroglobulin (in papillary and follicular thyroid cancer).
Symptoms
You can read everything important about the typical signs of thyroid cancer in the article Thyroid Cancer – Symptoms.
Causes and risk factors
Not all causes of thyroid cancer have been completely clarified to date. However, there are some indications for the development of such tumors – also with regard to factors that increase the risk of disease. However, there are differences between the various types of thyroid carcinoma.
In many cases, however, the disease develops spontaneously without any apparent cause.