title: Familial vs sporadic papillary thyroid carcinoma: a matched-case comparative study showing similar clinical/prognostic behaviour.
abstract: OBJECTIVE
  Familial non-medullary thyroid cancer has been proposed as an aggressive clinical entity. Our aim in this study is to investigate potential distinguishing features as well as the biological and clinical aggressiveness of familial vs sporadic papillary thyroid carcinoma (PTC). We assessed clinicopathological characteristics, outcome measures and DNA ploidy.
  
  
  METHODS
  A matched-case comparative study.
  
  
  METHODS
  A series of patients with familial PTC (n=107) and two subgroups, one with three or more affected elements (n=32) and another including index cases only (n=61), were compared with patients with sporadic PTC (n=107), matched by age, gender, pTNM disease extension and approximate follow-up duration. Histological variant, extrathyroidal extension, vascular invasion, tumour multifocality and bilateral growth were evaluated. Ploidy pattern was analysed in available samples by DNA flow cytometry. The probabilities of disease-free survival (DFS) and overall survival (OS) were estimated according to the Kaplan-Meier (K-M) method.
  
  
  RESULTS
  No patient with familial PTC died of disease during follow-up (median, 72 months), contrarily to five patients (4.7%) (P=0.06) with sporadic PTC (median, 90 months). There was a significantly higher tumour multifocality in familial PTC (index cases subgroup) vs sporadic PTC (P=0.035), and a trend, in the familial PTC cohort with three or more affected elements, to show extrathyroidal extension (P=0.054) more frequently. No difference was observed in DNA ploidy status. The K-M analyses showed no significant differences between both entities in relation to DFS or OS.
  
  
  CONCLUSIONS
  Apart from multifocality, familial PTC appears to have similar clinical/prognostic behaviour when compared with sporadic forms of the disease.
authors.affiliation: Serviço de Anatomia Patológica.
authors.forename: António E
authors.initials: AE
authors.lastname: Pinto
authors.forename: Giovani L
authors.initials: GL
authors.lastname: Silva
authors.forename: Rui
authors.initials: R
authors.lastname: Henrique
authors.forename: Francisco D
authors.initials: FD
authors.lastname: Menezes
authors.forename: Manuel R
authors.initials: MR
authors.lastname: Teixeira
authors.forename: Valeriano
authors.initials: V
authors.lastname: Leite
authors.forename: Branca M
authors.initials: BM
authors.lastname: Cavaco
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002277:Carcinoma / Q000235:genetics* / Q000473:pathology; D002291:Carcinoma, Papillary / Q000235:genetics* / Q000473:pathology; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D018572:Disease-Free Survival; D005192:Family Health; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D000077273:Thyroid Cancer, Papillary; D013964:Thyroid Neoplasms / Q000235:genetics* / Q000473:pathology