title: Papillary thyroid carcinoma in Denmark 1996-2008: an investigation of changes in incidence.
abstract: BACKGROUND
  A rise in the incidence of thyroid cancer has been reported in several countries, and the increase is only seen in the papillary type. Increased detection due to higher resolution ultrasound and fine needle aspiration has been proposed as the explanation, recent registry studies however question this assumption.
  
  
  METHODS
  National, unselected, prospective cohort study of 1350 papillary thyroid cancer patients in Denmark from 1996 to 2008.
  
  
  OBJECTIVE
  To analyze changes in incidence by time and to identify factors which might influence detection rate.
  
  
  RESULTS
  A rise in incidence is seen with age standardized ratios increasing from 1.43 per 100.000 per year in 1996 to 2.16 per 100.000 per year in 2008. The median age at presentation was 46 years and median tumor size was 18 mm. Male/female ratio was 1/2.9. By dichotomizing the material in a time period before and after the 30th of June 2001, no significant change in the proportion of diagnosed tumors smaller than 1 or 2 cm was found, and 42.8% of the rise in incidence was explained by tumors larger than 2 cm. No significant change in diagnostic use of ultrasound or fine needle aspiration was found, and a significant change toward more extensive thyroid surgery could not be confirmed.
  
  
  CONCLUSIONS
  This study shows a significant rise in incidence of papillary thyroid carcinoma in Denmark from 1996 to 2008, which is not explained by increased use of preoperative diagnostic modalities. Other reasons need to be considered.
authors.affiliation: Department of ENT Head & Neck Surgery, Odense University Hospital, Denmark. slondero78@gmail.com
authors.forename: Stefano Christian
authors.initials: SC
authors.lastname: Londero
authors.forename: Annelise
authors.initials: A
authors.lastname: Krogdahl
authors.forename: Lars
authors.initials: L
authors.lastname: Bastholt
authors.forename: Jens
authors.initials: J
authors.lastname: Overgaard
authors.forename: Henrik Baymler
authors.initials: HB
authors.lastname: Pedersen
authors.forename: Thomas
authors.initials: T
authors.lastname: Frisch
authors.forename: Jens
authors.initials: J
authors.lastname: Bentzen
authors.forename: Peter Ulrik
authors.initials: PU
authors.lastname: Pedersen
authors.forename: Peer
authors.initials: P
authors.lastname: Christiansen
authors.forename: Christian
authors.initials: C
authors.lastname: Godballe
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002277:Carcinoma / Q000453:epidemiology* / Q000473:pathology; D002291:Carcinoma, Papillary / Q000453:epidemiology* / Q000473:pathology; D002648:Child; D016208:Databases, Factual; D003718:Denmark / Q000453:epidemiology; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D000077273:Thyroid Cancer, Papillary; D013964:Thyroid Neoplasms / Q000453:epidemiology* / Q000473:pathology; D055815:Young Adult