Thyroid Cancer

Arjun Mote, Dr. Lopamudra Das Roy

Published 2021

Abstract:

Thyroid cancer is common in people who have a history of exposure to high doses of radiation. The cancer is formed in the thyroid gland that is located at the base of the throat. Through this study of thyroid cancer, PubMed and other scholarly websites have been used to obtain and analyze information on thyroid cancer.

Discussions:

Through studying many articles, it is shown that if the cancer is caught early, the survival rate is exceptionally high. There is no direct cause for thyroid cancer; however, high radiation and low iodine can lead to thyroid cancer. Women are three times more likely to get thyroid cancer than men. Thyroid cancer is most prominent in older patients.

About the Cancer:

Thyroid Cancer is cancer that is formed in the thyroid gland at the base of the throat. It is below Adam's Apple. This gland is essential as it makes hormones that help control heart rate, blood pressure, body temperature, and weight (4). Thyroid cancer is a type of endocrine cancer that is highly treatable with an excellent cure rate. There are four types of Thyroid Cancer. Each type depends on how progressive the cancer is. These are papillary, follicular, medullary, and anaplastic (1,4).

How common is thyroid cancer?

According to the American Cancer Society (ACS), there will be an estimated 44,280 cases of thyroid cancer next year. There will be an estimated 2,200 deaths next year from thyroid cancer(1).

Causes:

Scientists are not sure what the direct cause of Thyroid Cancer is and why cells become cancerous. They believe that cells become malignant due to radiation exposure, a diet low in iodine, and family history (5).

Risk Factors:

● Gender: Women have three times the chance to get Thyroid Cancer than men.

● Being overweight or obese: According to the International Agency for Research on Cancer (IARC), people who have a higher BMI have a higher risk of developing thyroid cancer.

● Hereditary Conditions: Many different inherited conditions are linked to different types of Thyroid Cancer (1).

○ Familial adenomatous polyposis (FAP)- People with this syndrome are more likely to develop papillary thyroid cancer. This syndrome is most often caused by defects in the gene APC.

○ Cowden disease- Increased risk of thyroid problems and certain benign growths. If diagnosed with cancer, it is usually in the earlier stage. This syndrome is most often caused by defects in the gene PTEN.

○ Carney complex, type I- People with this syndrome may develop a number of benign tumors and hormone problems.

How to prevent:

Prevention is not really possible as Thyroid cancer is formed randomly for most people. However, if you feel you are at risk for Thyroid cancer, you can take Preventive surgery (1,5).

● Genetic tests can determine if you carry a mutation that puts you at risk for the first stage of thyroid cancer. If you have an altered gene, then you can take prophylactic surgery to remove the thyroid gland before the cancer becomes more aggressive.

● Increasing your iodine intake

● Foods that are high in iodine are seaweed, dairy, tuna, shrimp, and eggs (4).

Early Detection Signs and Symptoms:

Figure 1 [14]

● A lump in the neck

● Pain in the front of the neck, sometimes going up to the ears

● Hoarseness or other voice changes that do not go away

● Trouble swallowing

● Trouble breathing

● A constant cough that is not due to a cold (5)

Screening & Diagnosis:

There are several ways to screen for Thyroid Cancer (1,3).

● Neck palpation during a physical examinatio

● Ultrasound, which can identify both palpable and nonpalpable nodules

○ This can find smaller nodules

● Self Examination

○ Touching the neck to notice any unfamiliar bumps/swelling

● Tests of blood levels of thyroid-stimulating hormone

○ Checks the activity of the thyroid gland

● Radioiodine scan

● Computed tomography (CT) scan

● Magnetic resonance imaging (MRI) scan

● Positron emission tomography (PET) scan

Stage and Treatment:

Four stages of Thyroid Cancer

There are four types of Thyroid Cancer. Each type depends on how progressive the

cancer is. These are papillary, follicular, medullary, and anaplastic (1, 4, 5).

Papillary is the most common and most treatable of the four types of Thyroid Cancer.

Follicular and Medullary are also treatable, and there is no major risk of death. Anaplastic is the most aggressive form of Thyroid Cancer. The survival rate of patients with Anaplastic Cancer is meager as the cancer has been in the thyroid gland for quite some time and has grown tremendously. Overall, about one in five people with anaplastic thyroid cancer live at least one year after being diagnosed(2). This aggressive thyroid cancer is the most complex type to treat. It can grow quickly and often spreads into surrounding tissue and other parts of the body.

Treatment

● Surgery

○ Most common form to remove the cancer

● Radioiodine therapy

○ Swallow a pill or liquid containing a higher dose of radioactive iodine. The

radioiodine shrinks and destroys the diseased thyroid gland along with cancer

cells.

● Radiation therapy

○ Radiation kills cancer cells and stops them from growing.

● Chemotherapy

○ Kills cancer cells and stop cancer growth.

● Hormone therapy

○ Blocks the release of hormones that can cause cancer to spread or come back.

Global: Scenario

On a global scale for 2021, an estimated 44,280 adults (12,150 men and 32,130 women) in the United States will be diagnosed with thyroid cancer (2.)

Figure 2

Figure 3[11]

Above, we can see the age distribution of patients having thyroid cancer. As shown, most individuals are diagnosed with cancer in their 40s-49s and 50s-59s. In the charts on the right, thyroid cancer is three times more common in the female gender than in the male gender.

Ethnicity:

A study done in 2014 saw if different races and ethnicities were more likely to get thyroid cancer than other races. The study results revealed that Americans experienced the most significant increase in age-adjusted thyroid cancer incidence by 5.6%, followed by African Americans with 4.8% per year, American Indian/Alaskan natives with 3.2% per year, and Asians/Pacific Islanders with 2.3% per year (9). To conclude with this study, thyroid cancer is more common in Americans than all other races. Each year, the cases of thyroid cancer continue to increase no matter the race and ethnicity.

Is Lifestyle or Environment playing a role? Environment plays more of a role in relation to thyroid cancer. Many groups of chemicals may be hazardous and negatively affect the thyroid gland. The primary chemical pollutant, PCB, is found in coolants and lubricants. This pollutant has adverse effects on the thyroid gland that can lead to cancer. Other environmental factors include living in a volcanic environment, radiation, pollution, and chemical pollutants such as pesticides. Air pollution can come from factories, natural fires, urban traffic. Another dangerous chemical pollutant is Perchlorates. This is found in rocket fuel, fertilizer, smoking, production of ordnance, and fireworks. It restrains the iodine uptake (8).

Developed versus Developing Countries

The rate of thyroid cancer was higher in more developed countries. In wealthier countries, more tests occur, leading to thyroid cancer being diagnosed early and not later on. In Korea, for example, there were 149.8 cases per every 100,000 women. Other high-income countries (HICs) with very high incidence rates in women were Cyprus (48.7), Italy (30.3), the United States (26.8), and France (25.4) (13). In the least developed countries, there were meager incident rates. For example, only four women in India and Iran were diagnosed with thyroid cancer out of every 100,000 women. (13).

Is socio-economic situation playing a role in the treatment scenario?

Thyroid cancer is more commonly diagnosed in patients that have a higher socioeconomic status. However, when lower socioeconomic status groups are diagnosed, their cancer is frequently more advanced and caught in the later stages. This study identified three socioeconomic surrogate variables: insurance type, median income, and educational quartile. Nine thousand five hundred eighty-five children with

well-differentiated thyroid cancer remains were reviewed. The results showed that children with lower income, lower education, and insurance status were associated with a higher stage at diagnosis (6,7).

Conclusion: To conclude with thyroid cancer research, it is very curable in the first three phases, but if found in the anaplastic phase, the survival rate is not as high. Cancer can easily be noticeable by touching around the lower part of the neck. A high recommendation is to take a genetic test to see if you carry a specific mutation that puts you at risk for the first stage of thyroid cancer. Lastly, thyroid cancer can easily be preventable if standard, yearly screening takes place.

Work Cited

1. American Cancer Society. www.cancer.org/cancer/thyroid-cancer.html. Accessed 18 June

2021.

2. “Cancer of the Thyroid - Cancer Stat Facts.” SEER,

seer.cancer.gov/statfacts/html/thyro.html.

3. Lin JS, Aiello Bowles EJ, Williams SB, et al. Screening for Thyroid Cancer: A

Systematic Evidence Review for the U.S. Preventive Services Task Force [Internet].

Rockville (MD): Agency for Healthcare Research and Quality (US); 2017 May.

(Evidence Syntheses, No. 151.) Chapter 1, Introduction. Available from:

https://www.ncbi.nlm.nih.gov/books/NBK447371

4. “Thyroid Cancer-Patient Version.” National Cancer Institute,

www.cancer.gov/types/thyroid.

5. “Thyroid Cancer: Causes, Symptoms, Diagnosis, Treatment & Types.” Cleveland Clinic,

my.clevelandclinic.org/health/diseases/12210-thyroid-cancer.

6. Siu, Stephanie et al. “Is lower socioeconomic status associated with more advanced

thyroid cancer stage at presentation? A study in two Canadian centers.” Thyroid : official

journal of the American Thyroid Association vol. 24,3 (2014): 545-51.

doi:10.1089/thy.2013.0090

7. Garner, Evan F et al. “Effects of socioeconomic status on children with

well-differentiated thyroid cancer.” Surgery vol. 162,3 (2017): 662-669.

doi:10.1016/j.surg.2017.04.008