USPSTF, AAFP: Don't Screen Asymptomatic Adults for Thyroid Cancer

Harms Outweigh Potential Benefits, Say Experts

May 12, 2017 01:58 pm News Staff

On May 9, The U.S. Preventive Services Task Force (USPSTF) published a final recommendation statement(www.uspreventiveservicestaskforce.org) and evidence summary(www.uspreventiveservicestaskforce.org) on screening for thyroid cancer. Based on its review of the evidence, the USPSTF recommended against screening for thyroid cancer in asymptomatic adults -- a "D" recommendation.(www.uspreventiveservicestaskforce.org)

[X-ray of thyroid cancer patient]

In addition, the AAFP has released its own final recommendation, which mirrors that of the USPSTF.

The task force reviewed studies on the benefits and harms of screening and treatment for thyroid cancer and found that for patients asymptomatic for the disease, the harms of screening and treatment are likely to be greater than the benefits.

"While there is very little evidence of the benefits of screening for thyroid cancer, there is considerable evidence of the serious harms of treatment, such as damage to the nerves that control speaking and breathing," said USPSTF member Karina Davison, Ph.D., M.A.Sc., in a news release.(www.uspreventiveservicestaskforce.org) "What limited evidence is available does not suggest that screening enables people to live longer, healthier lives."

Story highlights
  • The U.S. Preventive Services Task Force has released its final recommendation statement against screening asymptomatic adults for thyroid cancer -- a "D" recommendation.
  • The task force reviewed studies on the benefits and harms of screening and treatment for thyroid cancer and found that for patients asymptomatic for the disease, the harms of screening and treatment are likely to be greater than the benefits.
  • In 1996, the task force also recommended against screening for thyroid cancer in asymptomatic adults using either neck palpation or ultrasound.

Data the task force reviewed on the harms of screening also suggested overdiagnosis is likely a substantial issue because it leads to an increase in thyroid cancer diagnoses without affecting the cancer mortality rate.

"Overdiagnosis occurs because screening for thyroid cancer often identifies small or slow growing tumors that might never affect a person during their lifetime," said USPSTF member Seth Landefeld, M.D., in the release. "People who are treated for these small tumors are exposed to serious risks from surgery or radiation, but do not receive any real benefit."

This final recommendation is largely consistent with the USPSTF's 2016 draft recommendation and its 1996 final recommendation. In that earlier recommendation statement, the task force also recommended against screening for thyroid cancer in asymptomatic adults -- specifically, with either neck palpation or ultrasound.

To update its 1996 recommendation, the USPSTF commissioned a systematic evidence review to examine the benefits and harms of screening for thyroid cancer in adults. This review also assessed the diagnostic accuracy of screening methods (including neck palpation and ultrasound) and the benefits and harms of treating screen-detected thyroid cancer -- factors that weren't included in the previous evidence review.

Furthermore, at the time, the USPSTF issued a "C" recommendation for screening asymptomatic adults with a history of upper body irradiation (primarily head and neck) in infancy or childhood. It should be noted that in 1996, a C recommendation meant there was insufficient evidence to recommend for or against a service.

Response to Public Comment

A draft version of the final recommendation statement was posted for public comment on the USPSTF website from Nov. 22 to Dec. 26, 2016.

Many commenters shared similar personal stories of how their physician noticed a lump during physical examination, often prompted by symptoms such as hoarseness or throat pain, and these respondents expressed concern that the recommendation would prevent diagnosis of such cancer cases.

Additionally, some physicians commented that they interpreted the recommendation as discouraging them from performing neck examinations.

In response, the USPSTF expanded the Clinical Considerations(www.uspreventiveservicestaskforce.org) section of the final recommendation statement to clarify that this recommendation does not apply to patients who experience hoarseness, pain, difficulty swallowing or other throat symptoms, or to patients who have lumps, swelling, asymmetry of the neck or other reasons for a neck examination.

Family Physician's Take

In November 2016, when the USPSTF's draft recommendation on this topic was released, Jennifer Frost, M.D., medical director for the AAFP Health of the Public and Science Division, told AAFP News there is no evidence that indicates treating thyroid cancer reduces mortality.

"If treatment doesn't improve outcomes, then early diagnosis through screening doesn't have value," she said, at the time. "Treatment, however, almost always has risks. In this case, the most common serious harms of treatment include hypoparathyroidism and laryngeal nerve palsy.

"Why do widespread screening in order to increase diagnosis when the treatment causes harm without improving mortality?"

Frost emphasized the importance of only recommending a screening program when the potential benefits outweigh the potential harms. "In this case, it's clear the potential harms outweigh any benefit," she said.

Related AAFP News Coverage
News in Brief: Week of March 30-April 3, 2015: USPSTF Says Evidence Insufficient for Thyroid Dysfunction Screening
(4/3/2015)

More From AAFP
American Family Physician: AFP by Topic: Thyroid and Parathyroid Disorders