Elsevier

Endocrine Practice

Volume 21, Issue 6, June 2015, Pages 686-696
Endocrine Practice

AACE/ACE Disease State Clinical Review
American Association of Clinical Endocrinologists and American College of Endocrinology Disease State Clinical Review: The Increasing Incidence of Thyroid Cancer

https://doi.org/10.4158/EP14466.DSCRGet rights and content

ABSTRACT

Objective: (1) Describe current epidemiology of thyroid cancer in the United States; (2) evaluate hypothesized causes of the increased incidence of thyroid cancer; and (3) suggest next steps in research and clinical action.

Methods: Analysis of data from Surveillance, Epidemiology and End Results System and the National Center for Vital Statistics. Literature review of published English-language articles through December 31, 2013.

Results: The incidence of thyroid cancer has tripled over the past 30 years, whereas mortality is stable. The increase is mainly comprised of smaller tumors. These facts together suggest the major reason for the increased incidence is detection of subclinical, nonlethal disease. This has likely occurred through: health care system access, incidental detection on imaging, more frequent biopsy, greater volumes of and extent of surgery, and changes in pathology practices. Because larger-size tumors have increased in incidence also, it is possible that there is a concomitant true rise in thyroid cancer incidence. The only clearly identifiable contributor is radiation exposure, which has likely resulted in a few additional cases annually. The contribution of the following causes to the increasing incidence is unclear: iodine excess or insufficiency, diabetes and obesity, and molecular disruptions. The following mechanisms do not currently have strong evidence to support a link with the development of thyroid cancer: estrogen, dietary nitrate, and autoimmune thyroid disease.

Conclusion: Research should focus on illuminating which thyroid cancers need treatment. Patients should be advised of the benefits as well as harms that can occur with treatment of incidentally identified, small, asymptomatic thyroid cancers.

Abbreviations: BMI = body mass index CT = computed tomography SEER = Surveillance, Epidemiology, and End Results

Section snippets

INTRODUCTION

Thyroid cancer has been much in the news lately because of reports of large increases in incidence. However, it is now recognized that not all pathologic entities labeled as cancer act similarly, nor do they all act aggressively. Also, it is increasingly recognized that measures of incidence, mortality, and survival may be fnected by many epidemiologic factors and may not always be reflective of either true increases in disease, treatment successes, or screening efforts (1). A current example

Epidemiologic Data

Data on the incidence of thyroid cancer are from SEER 9 (Surveillance, Epidemiology and End Results) Program, supported by the National Cancer Institute, from 1975 to 2011. SEER 9 covers approximately 10% of the U.S. population and includes the longest contributing sites to the program: Atlanta, Connecticut, Detroit, Hawaii, Iowa, New Mexico, San Francisco-Oakland, Seattle-Puget Sound, and Utah. SEER is the best source of population-based data available in the U.S. for cancer incidence,

Part I: Current Epidemiology of Thyroid Cancer in the U.S.

In 2014, it was estimated that there would be 62,980 new cases of thyroid cancer in the U.S. Thyroid cancer accounts for about 3.8% of new cancers diagnosed each year in the U.S. and is the ninth most common in incidence after prostate, breast, lung, colon, melanoma of the skin, bladder, non-Hodgkin's lymphoma, and renal cancer. Deaths due to thyroid cancer are uncommon. It was estimated that there would be an estimated 1,890 deaths due to thyroid cancer in the U.S. in 2014. The more common

DISCUSSION

The incidence of thyroid cancer has tripled over the past 30 years, with the majority of the rise occurring in the past 15 years. The overwhelming majority of the increase has been due to the increased detection of papillary cancer, a histologic type known to be commonly present at death without ever having caused symptoms. Tumors of all sizes have increased in incidence, but in absolute and relative terms the greatest increase has been observed in cancers less than 2 cm in size. Throughout,

CONCLUSION

Research should focus on illuminating which thyroid cancers need treatment. Patients should be advised of the benefits as well as harms that can occur with treatment of incidentally identified, small, asymptomatic thyroid cancers.

ACKNOWLEDGMENT

Dr. Davies received support from the Department of Veterans fnairs; Dr. Haymart received support from the National Institutes of Health (1K07CA154595-02).

REFERENCES (64)

  • DaviesL. et al.

    Current thyroid cancer trends in the United States

    JAMA Otolaryngol Head Neck Surg

    (2014)
  • JungC.K. et al.

    The increase in thyroid cancer incidence during the last four decades is accompanied by a high frequency of BRAF mutations and a sharp increase in RAS mutations

    J Clin Endocrinol Metab

    (2014)
  • MathurA. et al.

    Higher rate of BRAF mutation in papillary thyroid cancer over time: a single-institution study

    Cancer

    (2011)
  • HarachH.R. et al.

    Occult papillary carcinoma of the thyroid. A “normal” finding in Finland. A systematic autopsy study

    Cancer

    (1985)
  • Martinez-TelloF.J. et al.

    Occult carcinoma of the thyroid. A systematic autopsy study from Spain of two series performed with two different methods

    Cancer

    (1993)
  • MortensenJ.D. et al.

    Gross and microscopic findings in clinically normal thyroid glands

    J Clin Endocrinol Metab

    (1955)
  • WiestP.W. et al.

    Thyroid palpation versus high-resolution thyroid ultrasonography in the detection of nodules

    J Ultrasound Med

    (1998)
  • MorrisL.G. et al.

    The increasing incidence of thyroid cancer: the influence of access to care

    Thyroid

    (2013)
  • KweonS.S. et al.

    Thyroid cancer is the most common cancer in women, based on the data from population-based cancer registries, South Korea

    Jpn J Clin Oncol

    (2013)
  • HanM.A. et al.

    Current status of thyroid cancer screening in Korea: results from a nationwide interview survey

    Asian Pac J Cancer Prev

    (2011)
  • LeeT.J. et al.

    The incidence of thyroid cancer is affected by the characteristics of a healthcare system

    J Korean Med Sci

    (2012)
  • Smith-BindmanR. et al.

    Use of diagnostic imaging studies and associated radiation exposure for patients enrolled in large integrated health care systems, 1996–2010

    JAMA

    (2012)
  • GreenspanF.S.

    Thyroid nodules and thyroid cancer

    West J Med

    (1974)
  • CooperD.S. et al.

    Revised American Thyroid Association management guidelines for patients with thyroid nodules and differentiated thyroid cancer

    Thyroid

    (2009)
  • National Comprehensive Care Network, Guidelines for Thyroid Carcinoma. Available at: http://www.nccn.org. Accessed...
  • SunG.H. et al.

    Epidemiological and economic trends in inpatient and outpatient thyroidectomy in the United States, 1996–2006

    Thyroid

    (2013)
  • SchmidtW.A.

    Principles and Techniques of Surgical Pathology

    (1983)
  • GhosseinR. et al.

    Protocol for the examination of specimens from patients with carcinomas of the thyroid gland

    College of American Pathologists Protocols

    (2012)
  • VerkooijenH.M. et al.

    Diagnostic changes as a reason for the increase in papillary thyroid cancer incidence in Geneva, Switzerland

    Cancer Causes Control

    (2003)
  • LloydR.V. et al.

    Observer variation in the diagnosis of follicular variant of papillary thyroid carcinoma

    Am J Surg Pathol

    (2004)
  • EnewoldL. et al.

    Rising thyroid cancer incidence in the United States by demographic and tumor characteristics, 1980–2005

    Cancer Epidemiol Biomarkers Prev

    (2009)
  • MaloneM.K. et al.

    Thyroid cancers detected by imaging are not necessarily small or early stage

    Thyroid

    (2014)
  • Cited by (0)

    DISCLOSURE

    The authors have no multiplicity of interest to disclose.

    The opinions represented in the AACE/ACE Disease State Clinical Review: The Increasing Incidence of Thyroid Cancer are the expressed opinions of the Endocrine Surgery Scientific Committee of the American Association of Clinical Endocrinologists. AACE/ACE Disease State Clinical Reviews are systematically developed documents written to assist health care professionals in medical decision making for specific clinical conditions, but are in no way a substitute for a medical professional's independent judgment and should not be considered medical advice. Most of the content herein is based on literature reviews. In areas of uncertainty, professional judgment of the authors was applied.

    This review article is a working document that reflects the state of the field at the time of publication. Because rapid changes in this area are expected, periodic revisions are inevitable. We encourage medical professionals to use this information in conjunction with, and not a replacement for, their best clinical judgment. The presented recommendations may not be appropriate in all situations. Any decision by practitioners to apply these guidelines must be made in light of local resources and individual patient circumstances.

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