title: The changing epidemiology of thyroid cancer: why is incidence increasing?
abstract: OBJECTIVE
  Thyroid cancer incidence is increasing worldwide. Causes are highly debated.
  
  
  RESULTS
  Thyroid cancer increase has been associated to socioeconomic status, better access to healthcare and rising use of thyroid imaging. Therefore, the rise could be apparent because of the useless identification of a large reservoir of subclinical papillary lesions that will never affect patient health (overdiagnosis).However, not all epidemiological and clinical data support this hypothesis. The increasing number of large tumors, the increasing thyroid cancer-related mortality in spite of earlier treatment and the changes in thyroid cancer molecular profile suggest a true increase. Recently increased and thyroid-specific environmental carcinogens could be responsible, such as radiation (mostly medical radiation), increased iodine intake and chronic lymphocytic thyroiditis and environmental pollutants such as nitrates, heavy metals and other compounds largely used in the industrialized society. Possible mechanisms await further investigation.
  
  
  CONCLUSIONS
  The increased incidence of thyroid cancer is the likely result of two coexisting processes: increased detection (apparent increase) and increased number of cases (true increase) due to unrecognized thyroid-specific carcinogens.To identify causal factors and to differentiate stationary cancers from those that will progress are major urgent requirements for both clinical and scientific purposes.
authors.affiliation: aEndocrinology, Garibaldi Hospital Medical Center and Department of Clinical and Molecular Biomedicine, University of Catania bHumanitas, Catania Center of Oncology cMedical Oncology, University of Catania Medical School, Catania, Italy.
authors.forename: Riccardo
authors.initials: R
authors.lastname: Vigneri
authors.forename: Pasqualino
authors.initials: P
authors.lastname: Malandrino
authors.forename: Paolo
authors.initials: P
authors.lastname: Vigneri
mesh_terms: D004032:Diet; D004781:Environmental Exposure / Q000009:adverse effects; D004785:Environmental Pollutants / Q000009:adverse effects; D006801:Humans; D015994:Incidence; D007455:Iodine / Q000009:adverse effects; D008019:Life Style; D012307:Risk Factors; D012959:Socioeconomic Factors; D013964:Thyroid Neoplasms / Q000453:epidemiology* / Q000209:etiology; D014965:X-Rays / Q000009:adverse effects
chemical_list: D004785:Environmental Pollutants; D007455:Iodine