Study establishes epidemiology of thyroid cancer by type, demographic group

Researchers from the National Cancer Institute (NCI) and several U.S. universities recently analyzed state-based thyroid cancer data in order to determine the incidence of each variety of the disease among American demographic groups.

Their results, which appear in the journal Thyroid, indicate that while diagnoses of follicular, medullary and anaplastic thyroid cancers all appear to be on the rise across nearly every age group, papillary thyroid cancer (PTC) is still the most common histological variety of the disease among people of all ages, genders and ethnicities.

Researchers used data taken from the NCI’s Surveillance Epidemiology and End Results 13 Registries Database, which gathered information on diagnoses of thyroid cancer recorded in 13 states between the years 1992 and 2006.

The team found that among women, who are at least twice as likely as men to be diagnosed with PTC, Asian-Americans had the highest incidence of papillary thyroid tumors, with an estimated 164 cases of PTC per 100,000 female patients. Among men, Caucasians had the highest rate of PTC, at just under 54 cases per 100,000 male patients.

Caucasians also had the highest rate of follicular thyroid cancer among men, with nearly nine cases per 100,000 male patients. Among women, however, this form of the disease remained fairly evenly distributed between all ethnicities.

Hispanic patients of both genders had the highest incidence of medullary thyroid cancer - three cases per 100,000 female patients and two and a half cases per 100,000 male patients, respectively.

Finally, Hispanic women and Asian-American men had the highest rates of anaplastic thyroid cancer, the rarest and most lethal variety of the condition. Two and a half cases of anaplastic tumors occurred per 100,000 female Hispanics, while Asian-American men saw approximately one and a half cases of the cancer type per 100,000 male patients.

Overall, the most at-risk thyroid cancer sub-group was Asian-American women around the age of 40, which is the age at which the risk of PTC typically peaks in American females.

Nearly 45,000 cases of thyroid cancer are diagnosed every year in the U.S., according to the NCI.