Screening for thyroid cancer in asymptomatic persons results in more harms than benefits, according to a recommendation statement from the US Preventive Services Task Force (USPSTF) that was published in JAMA.
The USPSTF issued its new statement with moderate certainty (D recommendation), and the recommendation does not apply to patients who have hoarseness, pain, difficulty swallowing, or other throat symptoms or to those who have lumps, swelling, asymmetry of the neck, or other reasons to undergo a neck examination. The recommendation also does not apply to persons who have an increased risk of thyroid cancer due to a history of exposure to ionizing radiation, particularly those with a diet low in iodine, an inherited genetic syndrome associated with thyroid cancer, or a first-degree relative with a history of thyroid cancer.
The new recommendation is an update to the USPSTF’s 1996 statement, in which the task force recommended against screening for thyroid cancer in asymptomatic adults using either neck palpation or ultrasound.
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The task force evaluated the evidence regarding the benefits and harms of screening for thyroid cancer in asymptomatic adults, the diagnostic accuracy of screening, including neck palpation and ultrasound, and the benefits and harms of treatment in patients with screen-detected thyroid cancer.
Although the USPSTF found inadequate direct evidence regarding the benefits of screening, it determined that the magnitude of the overall benefits of screening and treatment “can be bounded as no greater than small, given the relative rarity of thyroid cancer, the apparent lack of difference in outcomes between patients who are treated vs monitored (for the most common tumor types), and observational evidence showing no change in mortality over time after introduction of a mass screening program.”
Furthermore, the task force found inadequate direct evidence on the harms of screening but concluded that “the overall magnitude of the harms of screening and treatment can be bounded as at least moderate, given adequate evidence of harms of treatment and indirect evidence that overdiagnosis and overtreatment are likely to be substantial with population-based screening.” The USPSTF therefore determined that the net benefit of screening for thyroid cancer is negative.
In an editorial in JAMA Otolaryngology–Head and Neck Surgery, Louise Davies, MD, MS, from the Department of Veterans Affairs Medical Center in White River Junction, Vermont, and Luc G. T. Morris, MD, MSc, from Memorial Sloan Kettering Cancer Center in New York City, stated, “The USPSTF recommendation should discourage clinicians from screening for thyroid cancer with neck palpation, ultrasonography, or other techniques. The basis for this recommendation is the absence of evidence that detection of low-risk asymptomatic papillary thyroid cancer is associated with better outcome than detection and treatment of symptomatic patients.
“In addition, given the prevalence of thyroid nodules and the typically slow growth trajectory of the most common form of thyroid cancer, screening programs will be associated with a clinically significant amount of harm. It is hoped that these recommendations will provide support in the United States for the development of monitoring programs for adults with small, incidentally identified cancers, with the ultimate goal of avoiding unnecessary treatments.”
References
- US Preventive Services Task Force. Screening for thyroid cancer. US Preventive Services Task Force Recommendation Statement. JAMA. 2017;317(18):1882-1887. doi:10.1001/jama.2017.4011
- Davies L, Morris LGT. The USPSTF recommendation on thyroid cancer screening. Don’t “check your neck.” JAMA Otolaryngol Head Neck Surg. 2017 May 9 [Epub ahead of print]. doi:10.1001/jamaoto.2017.0502
