title: Thyroid surgical practices shaping thyroid cancer incidence in North-Eastern Italy.
abstract: OBJECTIVE
  To investigate the effects of changing surgical practices on thyroid cancer incidence in the Veneto Region (North-Eastern Italy).
  
  
  METHODS
  Hospital discharge records of the period 2000-2010 were analyzed to detect trends in thyroid surgery rates by type of surgery and diagnosis. The association between surgery rates for benign and malignant diseases across the 21 Local Health Units (LHUs) was assessed by Poisson regression. In a second step, clinical and pathological charts of the year 2010 were retrieved from the larger regional surgical center. The proportions of total and incidental papillary thyroid micro carcinoma (PTMC) were compared with historical data. Factors influencing an incidental diagnosis of PTMC were analyzed by logistic regression.
  
  
  RESULTS
  Among 26,000 procedures performed in the Region, there was an increase with time in the proportion of total thyroidectomies (from 67% to 78%) and surgeries with a diagnosis of thyroid cancer (from 17% to 28%). Cancer surgery rates across LHUs resulted associated to surgery rates for benign diseases (P<0.001). In the largest regional center, the proportion of PTMC increased from 35% to 56%, of whom almost 60% were incidental cases. The probability of finding an incidental PTMC was higher in total thyroidectomies than in other procedures (odds ratio=1.84, 95% confidence interval 1.08-3.14).
  
  
  CONCLUSIONS
  Data from the Veneto Region suggest that the increase in PTMC is due to several factors: increased preoperative diagnosis, total gland removal, extensive histological examination. Moreover, geographical variations in cancer incidence were associated to surgery rates for benign diseases.
authors.affiliation: Department of Special Surgical Pathology, University of Padova, Padova, Italy.
authors.forename: Maria Rosa
authors.initials: MR
authors.lastname: Pelizzo
authors.affiliation: Department of Nuclear Medicine, Rovigo Hospital, Rovigo, Italy. Electronic address: domenico.rubello@libero.it.
authors.forename: Domenico
authors.initials: D
authors.lastname: Rubello
authors.affiliation: Department of Special Surgical Pathology, University of Padova, Padova, Italy.
authors.forename: Chiara
authors.initials: C
authors.lastname: Bernardi
authors.affiliation: Department of Special Surgical Pathology, University of Padova, Padova, Italy.
authors.forename: Giancarlo
authors.initials: G
authors.lastname: Gemo
authors.affiliation: Department of Special Surgical Pathology, University of Padova, Padova, Italy.
authors.forename: Loris
authors.initials: L
authors.lastname: Bertazza
authors.affiliation: SER-Epidemiological Department, Veneto Region, Padova, Italy.
authors.forename: Elena
authors.initials: E
authors.lastname: Schievano
authors.affiliation: SER-Epidemiological Department, Veneto Region, Padova, Italy.
authors.forename: Ugo
authors.initials: U
authors.lastname: Fedeli
mesh_terms: D002277:Carcinoma / Q000175:diagnosis / Q000453:epidemiology* / Q000601:surgery; D002291:Carcinoma, Papillary; D005260:Female; D006801:Humans; D015994:Incidence; D033162:Incidental Findings; D007558:Italy / Q000453:epidemiology; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D016012:Poisson Distribution; D012044:Regression Analysis; D012189:Retrospective Studies; D000077273:Thyroid Cancer, Papillary; D013959:Thyroid Diseases / Q000453:epidemiology / Q000601:surgery*; D013964:Thyroid Neoplasms / Q000175:diagnosis / Q000453:epidemiology* / Q000601:surgery; D013965:Thyroidectomy / Q000639:trends*; D013997:Time Factors
keywords: Incidental diagnosis; Papillary microcarcinoma; Thyroid; Thyroid surgical practices; Tumor incidence