Thyroid cancer is a cancer that originates from the cells of the thyroid gland. This cancer is much less common than others and the course of the disease is quite good. If the correct diagnosis and treatment is applied, the disease can be completely eliminated. Thus, the person can live for a long time. Its incidence in the community is 4.2%. The lifetime risk of thyroid cancer in women is about 0.7%, and in men it is 025%. As can be seen from these percentages, it is a rare cancer. In the USA, 12 thousand new cases of thyroid cancer occur every year. Thyroid cancer is not a single type. In order of frequency, it is divided into 4 groups as papillary cancer, follicular cancer, medullary cancer and anaplastic cancer.
Types of Thyroid Cancer
Papillary Cancer: It is usually a benign cancer. Approximately 80% of all thyroid cancers are papillary cancer. It may not cause symptoms and may remain in the thyroid gland for many years. In this case, the patient may not have any complaints. It can be seen at any age and is better in young people. It most commonly occurs in the 40s. It can spread to other parts of the body. In this case, the course of the disease is worse.
Follicular cancer: It is the most common thyroid cancer after papillary cancer. However, its incidence is very low compared to papillae. This cancer can also spread. It often spreads to the membrane of the thyroid gland and to the vein. If it spreads to the membrane, its course is better than if it spreads to the vein. This type of cancer most commonly spreads to the lung and bone. There is also the possibility of spreading to neighboring structures, for example the trachea. It most often occurs after the age of 50. Follicular cancer progresses more rapidly and is more likely to recur.
Medullary Cancer: The thyroid gland secretes the hormone calcitonin. This event is carried out by C cells in the thyroid gland. Therefore, the secretion of this hormone is increased in cancer cases. In this cancer, the thyroid gland needs to be removed. If it has spread to the lymph nodes, these glands are also surgically removed. It is less common than the two cancers above. About 1/4 of the patients have familial transmission. In other words, the risk is increased in those with a family history of medullary thyroid cancer.
Anaplastic Cancer: It is the least common type of thyroid cancer. It runs very fast. The mass in the thyroid develops and grows rapidly. In cases where breathing is difficult, the trachea may need to be removed. Radiotherapy and chemotherapy are applied.
Causes of Thyroid Cancer
The reason is not yet fully known. However, according to studies, thyroid cancer has been seen in people exposed to some radioactive substances. The most important of these substances is uranium. For example, with the nuclear power plant accident in Chernobyl, the incidence of thyroid cancer has increased in people living in this region. Genetic mutations are thought to play a role in some thyroid cancers.
One of the common questions is whether some radioactive substances used during diagnosis or treatment cause cancer. The amounts of substances used for this purpose are quite small. Excretion times are much shorter. That’s why they don’t cause cancer.
What are the Symptoms of Thyroid Cancer?
Most thyroid cancers do not have any complaints. The disease does not give any symptoms. In some cases, a mass has occurred in the neck. In a minority of patients, there may be a feeling of discomfort in the throat, pain, difficulty in breathing, hoarseness, and difficulty in swallowing. However, these are seen in a minority of patients. Many thyroid cancers do not show symptoms. In fact, at the time of diagnosis, some of the patients have spread to other organs.
How is Thyroid Cancer Diagnosed?
First, tests are done to determine the amount of hormones in the blood. Whether the hormone levels are high or not, other tests should be done. Because these values are high in some thyroid cancers and normal in others. A mass in the thyroid is seen with ultrasonography. However, it cannot be determined whether this mass is cancer or not. A biopsy is required to make the definitive diagnosis. . It gives information about the appearance of the mass or nodule. Fine-needle aspiration biopsy is also performed. This method is applied to all masses seen in the thyroid. It is quite valuable. The poor type of cancer, the spread of the tumor, its large diameter (>1cm), and late initiation of the treatment lead to a poor prognosis of the disease. The course of the disease is better if the tumor is in a single focus, has not spread, and is small in diameter.
Thyroid Cancer Treatment
Surgery: In all thyroid cancers, the thyroid gland is surgically removed. Rapid microscopic examination is performed during surgery. The entire thyroid gland is removed and the surrounding lymph nodes are also removed. Removal of the entire thyroid gland is essential for effective post-operative treatment. Otherwise, the treatment will be useless. After the surgery, patients with papillary and follicular cancer are exposed to high doses of radioactive iodine in armored hospital rooms. Thus, it is aimed to kill cancer cells that have remained in other parts of the body. The dose of this radioactive iodine varies according to the extent of the cancer’s spread. In some cases, this method may need to be repeated. For this, a period of 6 months is expected to pass.
In medullary cancer, the amount of calcitonin is measured 2-3 months after surgery and removal of the thyroid gland and lymph nodes. If the amount of calcitonin measured during this period is less than 10 pg/ml, the treatment is successful and the tumor has been destroyed. Radioactive iodine treatment is also applied in this type of cancer. In anaplastic cancer, first surgery and radiotherapy, then chemotherapy are applied. After the treatment, patients are given thyroxine hormone. Because TSH level should be lowered. High TSH causes cancer recurrence.