Thyroid Cancer: Risk Factors and Prevention

Thyroid cancer is the fastest increasing newly diagnosed cancer worldwide regardless of age, sex, race or ethnic background. According to the Mayo Clinic the number of people diagnosed with the condition is rising is rising.  Women are three times more likely than men to be diagnosed with the condition and sadly, childhood cancer survivors are also at an increased risk. The National Cancer Instituted noted that during the year 2011, an estimated 36,550 women were diagnosed with thyroid cancer in the USA, compared to 11,470 men.

RISK FACTORS:  Columbia University Medical Center noted that 20 to 25 percent of patients with medullary thyroid cancer and 5 percent of patients with papillary thyroid cancer have a family member who had thyroid cancer.

One type of medullary thyroid cancer, MEN 2A associated medullary thyroid cancer, usually results from a mutation of the gene RET proto-oncogene. Another type of medullary thyroid cancer, familial medullary thyroid cancer, is passed down through families.

Another genetic condition that increases the risk of thyroid cancer is familial adenomatous polyposis, a condition in which the patient develops multiple benign polyps in her colon that will become malignant if not removed. Cetta et al. noted that papillary thyroid cancer is a rare manifestation of familial adenomatous polyposis.

Exposure to radiation is another risk factor of thyroid cancer, such as radiation therapy that is targeted to the neck. Before the link between radiation and thyroid cancer was known, radiation was used to treat many benign diseases.

MedlinePlus noted that people who had radiation therapy during childhood have an increased risk of thyroid cancer. People exposed to radiation through nuclear plant accidents or nuclear weapons also have a higher risk of developing thyroid cancer.

People who have either had a goiter or who have a family history of goiters also have an increased risk of developing thyroid cancer. A goiter is a noncancerous enlargement of the thyroid gland. Goiters may occur for unknown reasons.

People who do not get enough iodine in their diet may develop colloid goiters, or endemic goiters. MedlinePlus stated that on some occasions, medications such as aminoglutethimide and lithium can cause nontoxic goiters, or sporadic goiters.

PREVENTION: While there is no way to prevent thyroid cancer, people at risk can take certain precautions. For example, the MayoClinic.com noted that people with the genetic mutation that puts them at increased risk for medullary thyroid cancer may choose to have a prophylactic thyroidectomy. Prophylactic thyroidectomy is surgery on the thyroid gland done to prevent medullary thyroid cancer.

In cases of a radiation emergency, people at risk, such as people living near a nuclear power plant, may take potassium iodine to prevent the thyroid gland from taking in radioactive iodine released in the air. The Centers for Disease Control and Prevention warned that potassium iodine is only taken when advised by a physician, emergency management official or public health official.

REFERENCES:

• National Cancer Institute. Cancer of the Thyroid – Surveillance Epidemiology and End Results. Web. 10 January 2012  

• Cetta F, Curia MC, Montalto G, Gori M, Cama A, Battista P and Barbarisi A. “Thyroid Carcinoma Usually Occurs in Patients with Familial Adenomatous Polyposis in the Absence of Biallelic Inactivation of the Adenomatous Polyposis Coli Gene.” The Journal of Clinical Endocrinology and Metabolism, January 2000. Web. 10 January 2012 

• MedlinePlus Medical Encyclopedia. Goiter – Simple. Web. 10 January 2012 

• Columbia University Medical Center. Thyroid Cancer – Risk Factors. Web. 10 January 2012 

• MayoClinic.com. Thyroid Cancer. Web. 10 January 2012 

• MedlinePlus Medical Encyclopedia. Thyroid Cancer. Web. 10 January 2012 

• Centers for Disease Control and Prevention. Potassium Iodine. Web. 10 January 2012 

Reviewed January 10, 2011

by Michele Blacksberg RN