title: The long-term outcomes of the second generation of familial nonmedullary thyroid carcinoma are more aggressive than sporadic cases.
abstract: BACKGROUND
  Familial nonmedullary thyroid carcinoma (FNMTC) is frequently detected, but the prevalence or the aggressiveness of FNMTC is still unclear. We aimed to investigate the prevalence, clinical characteristics, and prognosis of FNMTC.
  
  
  METHODS
  This study included 3056 nonmedullary thyroid carcinoma (NMTC) patients who were pathologically confirmed to exhibit differentiated thyroid carcinoma from January 1962 through March 2010. The duration of follow-up was 6.2±6.2 years.
  
  
  RESULTS
  The prevalence of FNMTC was 9.6%; 37.9% of the FNMTC patients exhibited a parent-offspring relationship, and 62.1% exhibited a sibling relationship. FNMTC was smaller in tumor size (1.2±0.9 vs. 1.4±1.1 cm) and more multifocal (33.6% vs. 27.0%) than sporadic cases. FNMTC presented higher recurrence rates (29.5% vs. 19.8%) and shorter recurrence-free survival than sporadic NMTC (p=0.046). When we compared sporadic NMTC with parent-offspring or sibling FNMTC separately, parent-offspring FNMTC was more multifocal (39.3% vs. 27.0%), while sibling FNMTC was more prevalent in female patients (89.6% vs. 82.5%) and presented smaller tumors (1.2±0.8 vs. 1.4±1.1 cm) than sporadic NMTC. The recurrence rate was higher than that of sporadic NMTC in parent-offspring FNMTC (35.6% vs. 19.8%) but not in sibling FNMTC. Among the 123 parent-offspring FNMTC cases, the second generation exhibited an earlier age at the diagnosis (38±11 vs. 57±11 years), more extrathyroidal invasion (57.8% vs. 29.4%), a higher recurrence rate (50.0% vs. 19.0%), and shorter recurrence-free survival (p=0.015) than the first generation.
  
  
  CONCLUSIONS
  FNMTC was found to have a very high prevalence in our population. Parent-offspring FNMTC demonstrated higher recurrence than sporadic NMTC; specifically, the second generation of parent-offspring FNMTC cases exhibited more aggressive clinical characteristics than the first generation.
authors.affiliation: Department of Internal Medicine, College of Medicine, Seoul National University, Seoul, Republic of Korea.
authors.forename: Young Joo
authors.initials: YJ
authors.lastname: Park
authors.forename: Hwa Young
authors.initials: HY
authors.lastname: Ahn
authors.forename: Hoon Sung
authors.initials: HS
authors.lastname: Choi
authors.forename: Kyung Won
authors.initials: KW
authors.lastname: Kim
authors.forename: Do Joon
authors.initials: DJ
authors.lastname: Park
authors.forename: Bo Youn
authors.initials: BY
authors.lastname: Cho
mesh_terms: D000328:Adult; D017668:Age of Onset; D000368:Aged; D002291:Carcinoma, Papillary / Q000453:epidemiology / Q000235:genetics* / Q000473:pathology*; D018572:Disease-Free Survival; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D009362:Neoplasm Metastasis / Q000235:genetics; D009364:Neoplasm Recurrence, Local; D009367:Neoplasm Staging; D056910:Republic of Korea / Q000453:epidemiology; D012737:Sex Factors; D013964:Thyroid Neoplasms / Q000453:epidemiology / Q000235:genetics* / Q000473:pathology*; D013966:Thyroiditis / Q000150:complications