What is thyroid cancer?
Thyroid cancer is a type of endocrine cancer that begins in the thyroid gland and actually means the abnormal and out-of-control growth of thyroid cells. Thyroid cancer can occur at any age and gender, and even cases of thyroid cancer in children have been reported. In general, this cancer is a very treatable disease and the treatment success rate is high. Thyroid surgery is one of the main treatments for thyroid cancer and if it is done at the right time and by an experienced doctor, it can completely eradicate thyroid cancer.
Types of thyroid cancer
Health experts classify thyroid cancer based on the type of cells from which the cancer grows. Based on this, there are 4 types of thyroid cancer.
Up to 80% of all thyroid cancers are of the papillary type. This type of cancer progresses slowly. Although papillary thyroid cancer often spreads to the lymph nodes in the neck, the disease responds well to treatment. Papillary cancer is highly treatable and rarely leads to death.
About 2% of thyroid cancers are medullary type. A quarter of people with medullary thyroid cancer have a family history of this disease. A defective gene (genetic mutation) may be the cause of this cancer.
Follicular thyroid cancer accounts for up to 15% of thyroid cancer diagnoses. This cancer is more likely to spread to the bones and organs such as the lungs. If follicular thyroid cancer spreads and turns into metastatic cancer, treatment will be much more difficult.
This aggressive thyroid cancer can progress quickly and often spreads to surrounding tissues and other parts of the body. Anaplastic thyroid cancer is much more difficult to treat than other types of thyroid cancer. The probability of this rare type of cancer is about 2%.
Symptoms of thyroid cancer
Most thyroid cancers do not cause any signs or symptoms in the early stages of the disease. As the cancer progresses, you may notice the following symptoms:
- feeling a mass (nodule) in the neck; Don’t panic if you have a thyroid nodule. Most nodules are benign (not cancerous). Out of 20 thyroid nodules, only 3 cases are cancerous (malignant).
- Feeling of tightness in the collar
- Voice changes; Including hoarseness and harshness of voice
- Difficulty in swallowing
- Swollen lymph nodes in your neck
- Pain in the neck, throat, jaw or ears
If your thyroid cancer has spread to other parts of the body (metastasized), you may experience symptoms such as:
- Fatigue
- Loss of appetite
- nausea and vomiting
- Sudden and unexplained weight loss
What is the cause of thyroid gland cancer?
Thyroid cancer occurs when thyroid cells make changes in their DNA. A cell’s DNA contains instructions that tell the cell what to do. The changes, which doctors call mutations, tell cells to grow and multiply faster. While healthy cells die naturally, mutated cells continue to live.
The accumulation of these cells forms a mass called a tumor. The tumor can grow large enough to invade nearby tissue and spread to the lymph nodes in the neck (metastasize).
For most thyroid cancers, it is not known what causes the DNA changes to cause the cancer.
Which people are more at risk of thyroid cancer?
Certain factors such as exposure to radiation, low iodine diet and defective genes can increase the risk of developing thyroid gland cancer. Other risk factors include:
- Enlargement of the thyroid (goiter)
- Family history of thyroid disease or thyroid gland cancer
- Thyroiditis (inflammation of the thyroid gland)
- Gene mutations or changes that cause endocrine diseases, such as multiple endocrine neoplasia syndrome type A 2 (MEN2A) or type 2B (MEN2B
- Low consumption of iodine
- Obesity (high body mass index)
- Radiation therapy for head and neck cancer; Especially during childhood.
- Exposure to radioactive waves caused by nuclear weapons or power plant accident
Benign thyroid cancer
Maybe hearing the term benign cancer seems strange to you and you think that cancer is not always malignant?! The fact is that lumps or nodules that develop in the thyroid gland are not always cancerous. Most of the time, these thyroid nodules are benign and do not cause problems in thyroid function.
In such cases, you may hear that the person has benign thyroid cancer. If there is a benign thyroid cancer, it does not threaten a person’s life and it is enough to evaluate these masses regularly. In cases where benign thyroid masses become so large that they interfere with swallowing and voice, the doctor may recommend thyroid surgery to remove them.
Malignant thyroid cancer
Malignant thyroid cancer, as its name suggests, are tumors that can invade the surrounding tissue and even spread to other areas of the body. This type of cancer can be treated if diagnosed on time and receiving appropriate treatment. Treatment of malignant thyroid cancer, depending on the severity of the cancer, may include surgery to remove the thyroid gland, treatment with radioactive iodine, and hormone therapy after surgery.
Diagnosis of thyroid cancer
If you have an enlarged thyroid nodule or other symptoms of thyroid gland cancer, your doctor may prescribe one or more of the following tests for a more accurate diagnosis.
Physical examination:
Your neck specialist will examine you to detect thyroid changes such as a lump (nodule) in the thyroid. He may also ask you about cancer risk factors such as previous exposure to radiation and family history of thyroid cancer.
Thyroid function blood test:
Tests that measure levels of thyroid-stimulating hormone (TSH) and the hormones produced by the thyroid gland (T3 and T4) may give your doctor clues about your thyroid health.
Ultrasound imaging:
Ultrasound uses high-frequency sound waves to create images of the body’s structure. To create an image of the thyroid, an ultrasound transducer is placed at the base of your neck. The appearance of the thyroid nodule on the ultrasound image (including size and shape) helps the doctor to determine if there is a possibility of cancer.
Signs that a thyroid nodule is cancerous include calcium deposits (microcalcifications) within the nodule and an irregular border around the nodule. If a nodule is highly likely to be cancerous, more tests are needed to confirm the diagnosis and determine the type of cancer. The doctor may also use ultrasound to create images of lymph nodes in the neck to look for signs of cancer.
Thyroid tissue sample removal:
During a fine-needle aspiration biopsy, your doctor inserts a long, thin needle through your skin into the thyroid nodule. Usually, ultrasound imaging will be used to precisely guide the needle. The doctor will use a needle to remove some thyroid cells, and a sample will be sent to a lab for analysis.
In the laboratory, the pathologist examines the tissue sample under a microscope and determines whether cancer is present. The results are not always clear. In some types of thyroid cancer (especially follicular thyroid cancer), the results may be inconclusive.
In this case, the doctor may recommend another biopsy procedure or an operation to remove the thyroid nodule for testing. Specialized tests of cells to check for gene changes (molecular marker testing) can also be helpful.
An imaging test that uses a radioactive tracer:
A radioactive iodine scan uses a radioactive form of iodine and a special camera to detect thyroid cancer cells in your body. This method is often used after surgery to find cancer cells that may have remained. This test is very useful for papillary and follicular cancers.
Healthy thyroid cells absorb and use iodine from the blood. Some types of thyroid cancer cells also do this. When radioactive iodine is injected into a vein or swallowed, every thyroid cancer cell in the body takes up the iodine. Any cell that takes up iodine will show up in radioactive iodine scans.
Other imaging tests:
Your doctor may order one or more other imaging tests, including ultrasound, CT scan, and MRI, to determine whether the cancer has spread beyond the thyroid gland.
Genetic testing:
Some of the medullary thyroid cancers are caused by hereditary genes that are passed from parents to children. If medullary thyroid cancer is diagnosed, the doctor may recommend a genetic test. Finding out if you have an inherited gene can help you understand your risk of other types of cancer and know if your inherited gene may be passed on to your child.
Does thyroid cancer spread? Metastasis of thyroid cancer
Doctors use a staging system to determine if thyroid cancer has spread and how far it has spread. Generally, when cancer cells metastasize in the thyroid, they first spread to nearby structures and lymph nodes.
After that, the cancer can spread to distant lymph nodes, organs, and bones. Thyroid cancer stages vary from 1 (I) to 4 (IV). Simply put, the higher this number is, the more the cancer has spread.
Thyroid cancer can spread (metastasize) to other parts of the body, such as the liver, lungs, or bones. Diagnosing and treating thyroid cancer in the early stages reduces the risk of metastasis.
Does thyroid cancer come back?
People with thyroid cancer usually have a positive outlook and survival rate if the cancer is diagnosed early, but sometimes the disease may return (recur) even after successful treatment. Because thyroid cancer progresses slowly, it may take up to 20 years for it to recur. In general, cancer recurrence occurs in 30% of cases.
The rate of recurrence may vary depending on its type and stage of diagnosis. According to research, the average recurrence rate of follicular thyroid cancer (the second most common type of thyroid cancer) is about 13.6%. For medullary thyroid cancer, it is estimated that the recurrence rate can be up to 50%; Even if surgical removal of the primary tumor is successful.
Thyroid cancer treatment
Thyroid cancer treatment depends on the size of the tumor and how far the cancer has spread and includes the following:
Thyroid surgery:
Surgery is the most common and main treatment for thyroid cancer. Depending on the size and location of the tumor, the surgeon may remove part of the thyroid gland (lobectomy) or the entire gland (thyroidectomy). The surgeon also removes nearby lymph nodes where the cancer cells have spread.
Treatment with radioactive iodine:
In radioactive iodine therapy, you swallow a pill or liquid that contains a higher dose of radioactive iodine than the amount used in a diagnostic radioactive iodine scan. Radioactive iodine shrinks and destroys thyroid cancer cells.
This treatment is very safe. The thyroid gland absorbs almost all of the radioactive iodine, and the rest of your body will be exposed to minimal radiation.
Radiotherapy:
This method destroys cancer cells and stops their growth. In external radiation therapy, a device is used to send strong beams of energy directly to the tumor site. Internal radiation therapy (brachytherapy) includes placing radioactive seeds inside or around the tumor; In fact, in this method, the main source of radioactive radiation is placed inside or around the tumors.
Chemotherapy:
Intravenous or oral chemotherapy drugs kill cancer cells and stop cancer growth. Very few people with thyroid cancer will need chemotherapy.
Hormone Therapy:
This treatment prevents the release of hormones that can cause the cancer to spread or recur.
Injection of alcohol into the cancerous areas of the thyroid:
Alcohol ablation, also called ethanol ablation, involves using a needle to inject alcohol into small areas of thyroid cancer. In this method, ultrasound imaging will be used to precisely guide the needle. Alcohol causes thyroid cancer cells to shrink.
Prevention of thyroid cancer
Most people with thyroid cancer have no known risk factors for developing it, so prevention is mostly impossible. But if you know you are at risk of developing this cancer, you may be able to take the following steps.
Reducing exposure to radiation:
Exposure to radiation, especially during childhood, is a known risk factor for cancer. For this reason, doctors no longer use radiation to treat less serious diseases. Imaging tests like X-rays and CT scans also expose children to radiation (at much lower doses), so it’s not known how much they might increase the risk of thyroid cancer (or other cancers).
But to be safe, children should not undergo these tests; Unless they are really needed. If needed, these tests should be performed using the lowest radiation dose that still provides a clear image.
Preventive surgery:
Genetic tests can determine whether you carry a changed (mutated) gene that increases your risk of developing thyroid cancer. If you have the faulty gene, you may need to have preventive surgery to remove your thyroid gland before cancer develops.
Potassium iodide:
If you were exposed to radiation during a nuclear disaster, taking potassium iodide within 24 hours of exposure can reduce your risk of cancer. Potassium iodide prevents your thyroid gland from absorbing too much radioiodine, thus keeping your thyroid healthy.
FAQ
Thyroid surgery is the main treatment for thyroid cancer and if it is performed at the right time and by an experienced specialist, it will have a high success rate.
In general, there are 4 types of thyroid cancer, which are papillary, follicular, medullary and anaplastic thyroid cancer.
Yes. In general, there is a possibility of thyroid cancer returning in 30% of cases.
There are various methods to diagnose thyroid cancer, the most important of which are physical examination, thyroid function blood test, ultrasound, CT scan and thyroid sampling.
The exact cause of thyroid cancer is not known, but the existence of some risk factors can increase the probability of getting cancer; including thyroid inflammation, family history of thyroid cancer, exposure to radiation in childhood, ion mutations, low iodine intake, etc.
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