title: Both thyroid autoimmunity and increased serum TSH are independent risk factors for malignancy in patients with thyroid nodules.
abstract: OBJECTIVE
  To assess the relevance of thyroid autoimmunity and TSH as risk factors for malignancy in thyroid nodules (TN).
  
  
  METHODS
  Retrospective analysis on 2053 patients with single/prevalent TN submitted to fine needle aspiration cytology (FNAC). Anti-thyroid autoantibodies (ATA) [anti-thyroperoxidase (TPOAb), anti-thyroglobulin (TgAb)] and TSH were measured. Cytology was classified as benign (class II), indeterminate (class III), and suspicious or malignant (class IV). Histology was available in 301 patients. Associations of malignancy with independent variables were determined by multivariate logistic regression analysis.
  
  
  RESULTS
  Higher prevalence of class IV (14.2% vs 6.8%: p<0.001) and class III (23.5% vs 17.1%: p<0.001) were found in ATA+ vs ATA- TN. Histology confirmed increased prevalence of cancer in ATA+ (p<0.05) TN and in those with diffuse lymphocytic thyroid infiltration (p<0.05). Interestingly, the prevalence of malignancies observed in operated class III nodules was strikingly lower in ATA+ (1/20, 5%), than in ATA- patients (34/67, 50.7%; p<0.001). Increased independent odds ratio (OR) for malignancy was conferred by any ATA [OR 2.21; 95% confidence interval (CI)=1.49-3.29, p<0.0001]; TPOAb (OR 2.15; CI=1.42-3.25, p<0.0001) and TgAb (OR 1.67; CI=1.05-2.67, p<0.05), by serum TSH>1.0 μUI/ml (OR 1.95; CI=1.01-3.76, p<0.05), and by young age (10-29 yr: OR 2.09; CI=1.02-4.26, p<0.05). A formula was calculated to assess the relative contribution of ATA, TSH, and age to the risk of TN malignancy.
  
  
  CONCLUSIONS
  Both thyroid autoimmunity and increased TSH represent independent risk factors for TN malignancy.
authors.affiliation: Endocrinology Unit, Department of Medical Sciences M Aresu, University of Cagliari, Cagliari, Italy. francesco.boi@tin.it
authors.forename: F
authors.initials: F
authors.lastname: Boi
authors.forename: L
authors.initials: L
authors.lastname: Minerba
authors.forename: M L
authors.initials: ML
authors.lastname: Lai
authors.forename: B
authors.initials: B
authors.lastname: Marziani
authors.forename: B
authors.initials: B
authors.lastname: Figus
authors.forename: F
authors.initials: F
authors.lastname: Spanu
authors.forename: A
authors.initials: A
authors.lastname: Borghero
authors.forename: S
authors.initials: S
authors.lastname: Mariotti
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D015551:Autoimmunity; D015415:Biomarkers / Q000097:blood; D005260:Female; D006801:Humans; D007558:Italy / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D010903:Pituitary Gland, Anterior / Q000378:metabolism; D015995:Prevalence; D012189:Retrospective Studies; D012307:Risk Factors; D013961:Thyroid Gland / Q000276:immunology* / Q000473:pathology; D013964:Thyroid Neoplasms / Q000453:epidemiology / Q000209:etiology* / Q000276:immunology / Q000473:pathology; D016606:Thyroid Nodule / Q000453:epidemiology / Q000209:etiology* / Q000276:immunology / Q000473:pathology; D013967:Thyroiditis, Autoimmune / Q000097:blood / Q000276:immunology / Q000473:pathology / Q000503:physiopathology*; D013972:Thyrotropin / Q000097:blood* / Q000378:metabolism; D015854:Up-Regulation; D055815:Young Adult
chemical_list: D015415:Biomarkers; D013972:Thyrotropin