- Thyroid Cancer: Causes and Risk Factors
- Types of Thyroid Cancer
- Thyroid Cancer Risk Factors
- Risk Factors that can’t be Changed
- Risk Factors that You Can Keep Under Control
Thyroid Cancer: Causes and Risk Factors
It’s not yet possible to define, for sure, the reason for thyroid cancer. The disease implies that there occur mutations in your thyroid cells. These changes in the genes make the cells grow and multiply really fast. One more thing that’s important here is that the abnormal cells are unable to die, as it usually happens with the normal ones. The abnormal cells start accumulating and, consequently, the tumor appears. Keep in mind that the abnormal cells can also attack the tissues that are located closely and invade other areas of your organism.
Types of Thyroid Cancer
On the basis of the information about your thyroid cancer type, your doctor is able to prescribe you the necessary treatment and give and accurate future prognosis.
There are the following thyroid cancer types:
- Papillary thyroid cancer that is considered to be the most often to occur. It occurs in follicular cells that are responsible for the production and storage of thyroid hormones. Even though this type of cancer can occur at any age, as a rule, it attacks a person who is between 30 and 50 years old.
- Follicular thyroid cancer that, as well, occurs in the follicular cells located in your thyroid. Most often, there are exactly the people who are older than 50 who are diagnosed with it. Hurthle cell cancer is a type of follicular thyroid cancer that is more aggressive in character. However, you should know that cases of this cancer are really very rare.
- Medullary thyroid cancer that starts developing in the C cells (particular thyroid cells). These cells are responsible for the production of calcitonin – a particular hormone. If there is a high level of this hormone in your blood, this may be a sign of medullary cancer that’s yet at the very beginning. Irrespective of the fact that there is, as a rule, no genetic connection to the occurrence of the disease, there are several genetic syndromes that may significantly contribute to the development of the medullary thyroid cancer.
- Anaplastic thyroid cancer that, on the one hand, is very rare to occur and, on the other hand, the cancer that develops rather fast. We should also point out that it’s quite difficult to cure. Usually, it attacks people who are 60 years old or older.
- Thyroid lymphoma that is known to be a rare form of thyroid cancer. It starts developing in the immune system cells located in the thyroid. Besides, this type of cancer develops very fast, however, it attacks old people.
Thyroid Cancer Risk Factors
Anything that can significantly contribute to your chance of facing any disease is considered to be a risk factor. In this article, we are talking about thyroid cancer risk factors in particular. You should bear in mind that there exist risk factors that you are able to keep under control and risk factors you have no responsibility for. For instance, such a bad addiction as smoking refers to the first group while your family history refers to the second.
At the same time, having one or even several risk factors doesn’t necessarily mean that you’ll have the disease in future. In other words, risk factors don’t mean that you’re destined to fighting with cancer. Even if a thyroid cancer patient is said to have a risk factor, it’s quite complicated to measure its influence on the occurrence of the disease. Moreover, sometimes it so happens that people diagnosed with thyroid cancer have either few risk factor or there are some risk factors that are unknown yet.
It has been found out that some risk factors make a person more prone to having the disease.
Risk Factors that can’t be Changed
Your Gender and Age Group
For some unknown reasons, women are more prone to having thyroid cancer. Actually, this can be said almost about all the diseases that attack thyroid.
At the same time, even though thyroid cancer, as a rule, can occur at any age, it occurs earlier in women than men. Women face it in their 40-es or 50-es meanwhile men are usually attacked by it when they are over 60 or 70 years old.
Genetic Risk Factors
It has been stated that thyroid cancer may be caused by several inherited conditions. However, don’t forget that there are people who suffer from the disease irrespective of the fact that they don’t have any cases of thyroid cancer in their families.
If you deal with medullary thyroid cancer, bear in mind that in 8 out of 10 cases such like carcinomas (called MTCs, for short) occur as a result of the gene mutations. Doctors usually use a special term FMTC – familiar medullary thyroid carcinoma for it. These carcinomas can either occur alone or in tandem with other tumors.
When FMTC occurs in tandem with tumors that affect other endocrine glands as well, it’s called MEN 2 or multiple endocrine neoplasia of type 2. There exist 2 types of MEN 2 – MEN 2a and MEN 2b. Both these diseases occur because of the defects in the RET gene.
- If you’re dealing with MEN 2a, it means that there are pheochromocytomas (tumors responsible for the production of adrenaline) and parathyroid gland tumors as well.
- MEN 2b MTC means that there are pheochromocytomas and benign growth of the nerve tissue that occurs on your tongue. This benign tissue can grow anywhere else as well and is called neuroma. MEN 2b are less common to occur compared to MEN 2a.
All these forms of MTC that you inherit from your parents start developing in childhood or yearly adulthood. Besides, they grow very fast. As for MTC, it’s more aggressive in character if it’s about the MEN 2b syndrome. Remember that if there are any cases of MEN 2a or MEN 2b or cases of isolated FMTC in your family, your risk of fighting against MTC increases greatly. For this reason, you’re strongly recommended to make blood tests and undergo ultrasound examinations on a regular basis. This way, your doctor is able to detect any problems and prescribe you genetic tests if there is a necessity.
In case of other thyroid cancers, people who have genetic mutations inherited from parents are also more prone to developing the most frequently occurring forms of thyroid cancer. People suffering from the following syndromes (known as uncommon genetic conditions) have a very high rate of getting the disease:
FAP that’s short for Familial adenomatous polyposis. The syndrome occurs because of the mutations in the APC gene. Here the crux of the matter is that there occur lots of colon polyps and, therefore, a colon cancer may occur. Patients with these syndrome are also more prone to being diagnosed with other cancers, for instance, with papillary thyroid cancer. Gardner syndrome that’s known to be a subtype of FAP, means that there will also occur benign tumors. This syndrome is also caused by changes taking place in the APC gene.
Cowden disease implies that a patient is quite likely to suffer from thyroid problems and particular benign tumors (for instance, hamartomas). These patients are also prone to having thyroid, uterus, breast and other types of cancers. If it’s about thyroid cancer, it will be either papillary or follicular. As a rule, the syndrome occurs if there are changes taking place in the PTEN gene. Doctors also call it Multiple Hamartoma Syndrome or PTEN Hamartoma Tumor Syndrome.
Carney complex of type 1. If you’re diagnosed with the syndrome, it means that there may occur benign tumors in your organism. Besides, you may suffer from hormone problems. Patients with the syndrome also have a bigger risk of developing either papillary or follicular thyroid cancer. The reason for the syndrome are mutations in the PRKAR1A gene.
Familial nonmedullary thyroid carcinoma that seems to run in some families and, as a rule, occurs at an early age. Papillary thyroid cancer is considered to be the cancer that is genetically passed on from parents to a child. There are exactly the genes on the 19th and the 1st chromosome are believed to cause this type of cancers.
If you think that you may have a familial condition that significantly increases your risk of developing a thyroid cancer, talk it over with your doctor. He or she can prescribe you genetic counselling if there is a need.
Cases of Thyroid Cancer in Your Family
If you have a first-degree relative (a parent, brother, sister or child) who is suffering from thyroid cancer, be warned that you have an increased risk of having it as well. This is so even if you don’t have any syndrome that was passed on to you from your relatives. However, it’s yet impossible to say for sure if there is any genetic reason for it.
Risk Factors that You Can Keep Under Control
Being on a Diet that Involves a Low Amount of Iodine
Follicular thyroid cancer occurs more often in those areas of the world where people eat food with low amount of iodine. In the US, this disease doesn’t occur very often because people have enough iodine. It is usually added to table salt and other foods that people eat. If you don’t get enough iodine, you are also more prone to getting papillary cancer if you’re exposed to radiation as well.
Being Exposed to Radiation
It has been proved that a person exposed to radiation has an increased risk for thyroid cancer. Certain drugs as well as radiation fallout from power plants as a result of accidents and nuclear weapons are considered to be the main sources of radiation.
If you had radiation treatments directed to your head or neck when a child, you are prone to having thyroid cancer in future. In this case, your age and amount of radiation are taken into account. In overall, you have a bigger risk if the dose of radiation was high and you were really young when undergoing such like treatment.
Up until 1960-es there was radiation therapy used for treating the diseases that are not treated with it at present. They were the diseases like acne, fungus, infection of the scalp and tonsils or adenoids being enlarged. Later on, people who had undergone such like treatment turned out to have an increased risk for thyroid cancer. Risk factor also increases if a child is prescribed radiation therapy in case he or she is having lymphoma, Wilms tumor and neuroblastoma. However, the fact is that thyroid cancers occurring after radiation therapy are not more dangerous than any other thyroid cancers.
If a child is prescribed imaging tests (X-ray or CT), they can also serve as a source of radiation. At the same time, they expose a person to a low dose of radiation. Therefore, it can’t be said for sure how much these procedures contribute to the development of thyroid and other cancers as well. Even if there is said to be a risk, it’s quite small. Still, to be on the safe side, make sure that your child undergoes them only if it’s really strongly recommended and needed. Even in this case, the dose of radiation should be low. Actually, whether the dosage is high or low has nothing to do with how clear the image is.
According to some studies, children who were exposed to radiation as a result of a radioactive fallout from nuclear weapons and power plants have a higher risk of facing thyroid cancer in future. A vivid example of this are children who lived near Chernobyl. Later on, many of them were diagnosed with thyroid cancer. In 1986 there was a nuclear plant accident that resulted in lots of people being exposed to radiation. Those adults who lived close by or had to clean up the territory after the accident had a significantly higher risk of thyroid cancer. As for children who had enough iodine from foods they ate, their risk was a lot lower.
There also were several radioactive fallout accidents in certain regions of the US. They happened after the testing of nuclear weapons in western states in the 1950-es. However, the exposure rate was considerably lower than the one that occurred in Chernobyl. Scientists yet haven’t found out whether such like low radiation exposure can result in a higher risk of thyroid cancer. If you worry that you may be exposed to a radioactive fallout, talk it over with your doctor.