The thyroid is a gland that is located at the bottom of the neck, right below the Adam’s apple. The gland is responsible for releasing hormones that are important to regulate blood pressure, body temperature, heart rate, and body weight. When cancer occurs in thyroid cells, it is referred to as thyroid cancer. Initially, thyroid cancer might not show any symptoms, but as the condition progresses, it can cause swelling and pain in the neck.

What is thyroid and thyroid cancer?

The thyroid is a butterfly-shaped gland that is responsible for the production of the thyroid hormone. This hormone has a lot of important functions to perform, and one of them is regulating the metabolism of the body. The gland contains parafollicular cells that produce the thyroid hormone. 

When the production of the hormone is in excess, it is known as hyperthyroidism. The symptoms of hyperthyroidism include intolerance towards heat, anxiety, loss in body weight, and sweating. 

When the production of the thyroid hormone is too little, the condition is known as hypothyroidism. The symptoms include intolerance towards cold, gain in body weight, and thinning of hair.

The most common endocrine cancer, thyroid cancer, affects over 20,000 people in the country each year. However, that makes for only 1% of the total new cancers diagnosed in the country. 

When there is a mutation in the DNA, which is spontaneous or a result of any exposure to toxic substances, it causes alterations of healthy thyroid cells. These changes lead to the rapid multiplication of the cells and cause any type of cells present in the thyroid gland to mutate and turn cancerous.

Reports from the National Cancer Institute have shown that the cases of thyroid cancer have increased over the last 30 years. However, there hasn’t been any change in the number of deaths that have occurred due to thyroid cancer. 

Signs and symptoms of thyroid cancer

The most common signs and symptoms of thyroid cancer is a nodule or a lump in the part of the neck where the thyroid gland is located. The lump does not cause any pain and in most cases, it is found accidentally. In the majority of these cases, the thyroid gland is functioning properly when the lump is discovered. Patients show no signs or symptoms of thyroid cancer at this stage usually.

When the tumor has grown large enough, it starts affecting the adjoining and nearby parts as well. This can lead to problems such as dysphagia or problems with swallowing. This happens when the tumor starts to put pressure on the esophagus. However, though painful, this is highly uncommon.

In the case of thyroid cancer involving the laryngeal nerve, which regulates vocal cords, the patient might experience hoarseness. This happens due to paralysis of the vocal cords. Lumps in the neck are more commonly found in children. Usually, these lumps are not found in the thyroid gland. Except for swelling of the lymph nodes, which often leads to an ear infection or pharyngitis, no other kind of lump formations should be taken lightly. 

Different types of thyroid cancer

Thyroid cancer is not as common as other types of cancer. It falls on the 10th position in the list of most common types of cancer diagnosed in the country. Thyroid cancer is categorized based on the appearance of the cancer cells. There are well-differentiated and undifferentiated cancerous cells found in thyroid cancer patients. While well-differentiated cells are cancerous cells that look like healthy cells and multiply at a slow rate, undifferentiated cells are found to be growing at a rapid rate.

The various types of thyroid cancer are:

• Papillary thyroid cancer

In this type, well-differentiated cancer cells are found. This is the most common type of thyroid cancer. It is mostly seen in women who are in their childbearing years. This type of cancer is less aggressive, which means it does not spread quickly. It is also easily treatable.

• Medullary thyroid cancer

This is another type of thyroid cancer with well-differentiated cancer cells. In some cases of this type of cancer, a genetic component is found. This makes medullary thyroid cancer a part of endocrine gland cancer-related syndrome. This type of cancer usually begins in cells that are non-thyroid and are located in the thyroid gland. This has a different treatment approach as compared to other thyroid cancer types.

• Follicular thyroid cancer

This type of thyroid cancer usually spreads and has chances of recurring. Hurthle Cell Cancer is an advanced type of follicular thyroid cancer. Additionally, Follicular thyroid cancer is more prevalent in people above 50 years of age.

• Anaplastic thyroid cancer

This is the most aggressive and rare type of thyroid cancer. Although it is not common, it can be extremely difficult to cure.

• Thyroid lymphoma

Another rare form of thyroid cancer that starts in the immune cells that are present in the thyroid gland.

Causes of thyroid cancer

The exact cause of the condition is yet to be known. However, there are certain factors that can be linked to the increased risk of developing thyroid cancer. But even when a person is exposed to these risk factors, it cannot be known for sure if the person will develop thyroid cancer. Patients who do not have any risk factors can also develop thyroid cancer.

Risk factors associated with thyroid cancer

Usually, single thyroid lumps or nodules are non-cancerous. However, if these lumps occur in people who are younger than 30 or above 60 years of age, the chances of thyroid cancer can increase. Also, a single lump found in males has more chances of being cancerous than in women. If a lump is growing aggressively in size, it has a higher chance of being cancerous. This is also a dangerous sign.

Imaging tests such as CT scans and X-rays done on the neck do expose the part of the body to small amounts of radiation. However, these haven’t been found to be the cause for this condition yet. But it is still important to limit exposure to radiation.

Lack of iodine in the diet can also become a cause of thyroid cancer. But this might not be a problem in developed countries since iodine is used as food additives here, reducing the chances of developing thyroid cancer. Moreover, when the diet is low in iodine levels, it can increase the chances of thyroid cancer induced by radiation. Besides, there can also be a link between diabetes that is beyond control and increased chances of developing thyroid cancer.

Kids who have been exposed to radiation around the neck area can also be at a greater risk of developing thyroid cancer. There have been studies that have found that people who were undergoing radiation treatment 50-60 years back, when the ill effects of radiation were not completely known, are now highly susceptible to developing thyroid cancer. 

How is thyroid cancer diagnosed?

The presence of thyroid cancer can be identified through a physical examination or lab tests. During a physical examination, the presence of a small or big lump in the neck area can be revealed. In some cases, enlarged lymph nodes can also be identified. There are various laboratory tests that can be conducted for the diagnosis of thyroid cancer. These include the following:

• Thyroid scan
• Thyroid function tests
• An ultrasound
• Laryngoscopy
• Test to check the level of phosphorus in the blood
• Thyroid biopsy
• Test to check the level of calcium in the blood
• Test to check the level of calcitonin in the blood

Treatment options for thyroid cancer

The treatment course for thyroid cancer most commonly involves surgery to get rid of the tumor. There are a few options available for the patient, and which one is picked will depend on the clinical diagnosis of the patient.

The options include:

• Lobectomy

The thyroid gland consists of two lobes that are joined with each other in the middle with isthmus – a tissue bridge made of fibers. In cases where the tumor is only limited to a small area, the surgery is done to remove the lobe that has been affected.

• Total thyroidectomy

One of the most common surgical procedures to treat thyroid cancer, a total thyroidectomy is done to remove the complete thyroid gland. The surgery is also done to ensure that cancer does not occur again.

• Lymph node resection

In many cases, cancer can affect the lymph nodes. In such cases, the lymph nodes are removed with the help of this surgery. Which lymph nodes have been affected can only be identified during the surgery.

• Thyroid hormone replacement 

When the gland is removed surgically, the body will not be producing thyroid hormone anymore. Therefore, thyroid hormone replacement will be required. The patient will have to undergo regular blood tests to keep track of thyroid hormones available in the body for proper functioning. Patients who have undergone thyroidectomy will need to be on thyroid hormone replacement treatment life-long.

• Radioactive iodine

Thyroid tissue is responsible for absorbing iodine. Once a thyroidectomy is conducted, radioiodine may be given to the patient to make sure if any part of thyroid tissue is remaining it can be destroyed. The need to use this treatment will depend on how much the cancer has spread and how much thyroid-stimulating hormone levels are present. 

• Radiation therapy

In cases where the tumor has not absorbed iodine, radiation therapy can be given instead of radioactive iodine. If iodine has been absorbed by the tissue or not, it can only be known through radioactive iodine uptake tests, which are performed before surgery.

• Chemotherapy 

Although chemotherapy is not a common treatment option for thyroid cancer, in some cases it can be used when the patient does not respond to any other treatment options.

Prevention of thyroid cancer

Since the exact cause of thyroid cancer isn’t known yet, the ways to prevent it are yet to be known. 

One of the types of thyroid cancer, medullary thyroid cancer is genetic. If anyone in the family has suffered or suffers from thyroid cancer, one must consult their doctor. Their physician can recommend a genetic counselor, who will help one know their chances of developing thyroid cancer.

People exposed to nuclear radiation, such as those who reside near nuclear power plants, have a higher chance of developing thyroid cancer as compared to people who do not live nearby. It is important that one consults their doctor and takes potassium iodide pills if one is exposed to nuclear radiation. Also, one should never miss their annual check-ups and consult their doctor if one has been experiencing even the slightest of symptoms. This will help one ensure that if there is any complication, it can be identified and treated at an early stage.

Outlook for patients and cancer recurrence

When thyroid cancer is diagnosed at an early stage, it can be easily treated. Such patients respond better towards the treatment and usually enter the remission phase. Also, there are several types of thyroid cancers that are more recurrent than others. Even after a person goes into remission, it is important to keep going for regular appointments with the doctor. These checkups can be taking place lifelong since the doctor will have to check for any signs of cancer recurring. Routine checkups are also important to ensure that the correct amount of thyroid replacement hormones are received by the patient. The recurrence of thyroid cancer largely depends on how aggressively it has spread. If the spread is limited just to the thyroid gland, then the chances of recurrence reduce. On the other hand, if the cancer has spread and affected adjoining as well as distant body parts, then the chances of recurrence increases.