CLINICAL THYROIDOLOGY FOR PATIENTS
A publication of the American Thyroid Association
Rising thyroid cancer rates are not related to socioeconomic status and access to medical care
ABBREVIATIONS & DEFINITIONS
Thyroid nodule: an abnormal growth of thyroid cells that forms a lump within the thyroid. While most thyroid nodules are non-cancerous (benign), ~5% are cancerous.
Thyroid Ultrasound: a common imaging test used to evaluate the structure of the thyroid gland. Ultrasound uses soundwaves to create a picture of the structure of the thyroid gland and accurately identify and characterize nodules within the thyroid. Ultrasound is also frequently used to guide the needle into a nodule during a thyroid nodule biopsy.
Thyroid fine needle aspiration biopsy (FNAB): a simple procedure that is done in the doctor’s office to determine if a thyroid nodule is benign (non-cancerous) or cancer. The doctor uses a very thin needle to withdraw cells from the thyroid nodule. Patients usually return home or to work after the biopsy without any ill effects.
SEER: Surveillance, Epidemiology and End Results program, a nation-wide anonymous cancer registry generated by the National Cancer Institute that contains information on 26% of the United States population. Website: http://seer.cancer.gov/
Socioeconomic status (SES): an estimated measure of a person’s or group’s social and economic status compared to others in the general population. The information is based on income level, education and occupation.
Thyroid cancer is the fastest rising cancer in women. Indeed, the rates of thyroid cancer in the U.S. have been increasing over the past 30 years. The reason for this increase is largely unknown. Some believe that this is at least partly due to the more frequent use of thyroid ultrasound in recent years, which can detect smaller nodules not easily felt. Also, higher rates of thyroid cancer may be due to the more frequent use of thyroid biopsy of these smaller nodules over the last few decades. However, there has also been an increase in large cancers over the same time period. Access to health care to obtain thyroid exams and ultrasound is likely associated with socioeconomic status (SES). To determine if SES is associated with the recent increases in incidence of thyroid cancer, this study compared thyroid cancer incidence trends between low- and high-SES counties in the United States during the past three decades.
THE FULL ARTICLE TITLE:
Li N et al. Impact of enhanced detection on the increase in thyroid cancer incidence in the United States: review of incidence trends by socioeconomic status within the Surveillance, Epidemiology, and End Results registry, 1980-2008. Thyroid 2013;23:103-10. doi: 10.1089/thy.2012.0392. PMID: 23043274.
SUMMARY OF THE STUDY
This study includes all of the U.S. cases of thyroid cancer reported to the Surveillance, Epidemiology and End Results 9 (SEER 9) database from 1980 to 2008. The SEER database contains cancer information on ~26% of the national population. The SES of these 49,819 thyroid cancer patients was looked at using information from the U.S. Census. The authors found that thyroid cancer rates have risen in the past 30 years without regard to whether patients lived near a big city or what the SES was of the county in which the patient lived.
WHAT ARE THE IMPLICATIONS OF THIS STUDY?
The study shows us that the increasing rate of thyroid cancer in the U.S. is likely real and not a factor related to whether patients have good access to medical care or the level of their SES. However, these implications must be interpreted with caution. Only the information from about a quarter of the U.S. population is recorded in the SEER database and therefore it may not be truly representative of the entire nation. Also, the U.S. Census information provides socioeconomic data only by county, and, thus, is not applicable to an individual person. This study does suggest, however, that rising thyroid cancer rates are not affected by these factors.
— Angela M. Leung, MD, MSc
ATA THYROID BROCHURE LINKS
Thyroid cancer: http://www.thyroid.org/cancer-of-the-thyroid-gland