Thyroid Cancer: Screening -- Adults


General

Grade: D The USPSTF recommends against the service. There is moderate or high certainty that the service has no net benefit or that the harms outweigh the benefits. Discourage the use of this service.

Specific Recommendations

The USPSTF recommends against screening for thyroid cancer in asymptomatic adults. (D recommendation)

Frequency of Service

No information available.

Risk Factor Information

No information available.


Clinical

Patient Population Under Consideration

This recommendation applies to screening in asymptomatic adults. It does not apply to persons who experience hoarseness, pain, difficulty swallowing, or other throat symptoms or persons who have lumps, swelling, asymmetry of the neck, or other reasons for a neck examination. It also does not apply to persons at increased risk of thyroid cancer because of a history of exposure to ionizing radiation (eg, medical treatment or radiation fallout), particularly persons with a diet low in iodine, an inherited genetic syndrome associated with thyroid cancer (eg, familial adenomatous polyposis), or a first-degree relative with a history of thyroid cancer.45

Assessment of Risk

Although the USPSTF recommends against screening in the general asymptomatic adult population, several factors substantially increase the risk for thyroid cancer, including a history of radiation exposure to the head and neck as a child, exposure to radioactive fallout, family history of thyroid cancer in a first-degree relative, and certain genetic conditions, such as familial medullary thyroid cancer or multiple endocrine neoplasia syndrome (type 2A or 2B).4

Screening Tests

Although screening for thyroid cancer using neck palpation and ultrasound of the thyroid has been studied, the USPSTF recommends against screening in the general asymptomatic adult population.

Treatment and Interventions

Surgery (ie, total or partial thyroidectomy, with or without lymphadenectomy) is the main treatment of thyroid cancer. Additional treatment, including radioactive iodine therapy, may be indicated, depending on postoperative disease status, tumor stage, and type of thyroid cancer. External-beam radiation therapy and chemotherapy are not generally used to treat early-stage, differentiated thyroid cancer.


Rationale

Importance

In 2013, the incidence rate of thyroid cancer in the United States was 15.3 cases per 100,000 persons, which is a significant increase from 1975, when the incidence rate was 4.9 cases per 100,000 persons.1 The increase was 6.7% per year from 1997 to 2009, but the rate of increase has slowed to 2.1% per year in recent years (2009–2013).1 Meanwhile, the change in mortality rate has increased by only about 0.7 deaths per 100,000 persons each year.1 Most cases of thyroid cancer have a good prognosis.2 The 5-year survival rate for thyroid cancer overall is 98.1% and varies from 99.9% for localized disease to 55.3% for distant disease.3

Detection

The USPSTF found inadequate evidence to estimate the accuracy of neck palpation or ultrasound as a screening test for thyroid cancer in asymptomatic persons.

Benefits of Early Detection and Treatment

The USPSTF found inadequate direct evidence to determine whether screening for thyroid cancer in asymptomatic persons using neck palpation or ultrasound improves health outcomes. However, the USPSTF determined that the magnitude of benefit can be bounded as no greater than small, based on the relative rarity of thyroid cancer, the apparent lack of difference in outcomes between patients who are treated vs only monitored (ie, for the most common tumor types), and the observational evidence demonstrating no change in mortality over time after introduction of a population-based screening program.

Harms of Early Detection and Treatment

The USPSTF found inadequate direct evidence to assess the harms of screening for thyroid cancer in asymptomatic persons. The USPSTF found adequate evidence to bound the magnitude of the overall harms of screening and treatment as at least moderate, based on adequate evidence of serious harms of treatment of thyroid cancer and evidence that overdiagnosis and overtreatment are likely consequences of screening.

USPSTF Assessment

The USPSTF concludes with moderate certainty that screening for thyroid cancer in asymptomatic persons results in harms that outweigh the benefits.


Others

Other Considerations Research Needs and Gaps The USPSTF found no direct studies that compared screened vs unscreened populations or immediate surgery vs surveillance or observation and reported health outcomes (ie, morbidity, mortality, quality of life, or harms). Trials or well-designed observational studies that address the benefit of screening in high-risk persons (ie, persons with a history of radiation or family history of differentiated thyroid cancer) are important for understanding how to best advise these patients. Trials or well-designed observational studies of early treatment vs surveillance or observation of patients with small, well-differentiated thyroid cancer are also needed to identify patients at greatest risk for clinical deterioration. Finally, risk prediction tools and molecular markers are needed to help understand the prognosis of differentiated thyroid cancer. Recommendations of Others The American Cancer Society does not specifically recommend screening for thyroid cancer using neck palpation or any other method.30 In 1996, the American Academy of Family Physicians recommended against screening for thyroid cancer using neck palpation or ultrasound in asymptomatic persons.31 The Canadian Task Force on the Periodic Health Examination does not include examination of the thyroid in its 2015 Preventive Care Checklist Form.32 The American Thyroid Association33 and the American Association of Clinical Endocrinologists, American College of Endocrinology, and Associazione Medici Endocrinologi34 issued guidelines for the diagnosis and management of thyroid nodules in 2016; these guidelines included no recommendation on screening for thyroid cancer in asymptomatic persons.   Update of Previous USPSTF Recommendation This is an update of the 1996 USPSTF recommendation.29 In 1996, the USPSTF recommended against screening for thyroid cancer in asymptomatic adults using either neck palpation or ultrasound (D recommendation). In addition, using older methodology, the USPSTF issued a C recommendation for screening in asymptomatic adults with a history of radiation of the external upper body (primarily the head and neck) in infancy or childhood; in 1996, a C recommendation was defined as "insufficient evidence to recommend for or against." The USPSTF focused its current recommendation on the general asymptomatic adult population.


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